first commit

lib/form/advcheckbox.php

@@ -0,0 +1,150 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Advanced checkbox type form element
+ *
+ * Contains HTML class for an advcheckbox type form element
+ *
+ * @package   core_form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once('HTML/QuickForm/advcheckbox.php');
+require_once('templatable_form_element.php');
+
+/**
+ * HTML class for an advcheckbox type element
+ *
+ * Overloaded {@link HTML_QuickForm_advcheckbox} with default behavior modified for Moodle.
+ * This will return '0' if not checked and '1' if checked.
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_advcheckbox extends HTML_QuickForm_advcheckbox implements templatable {
+
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+
+    /** @var string html for help button, if empty then no help will icon will be dispalyed. */
+    var $_helpbutton='';
+
+    /** @var string Group to which this checkbox belongs (for select all/select none button) */
+    var $_group;
+
+    /**
+     * constructor
+     *
+     * @param string $elementName (optional) name of the checkbox
+     * @param string $elementLabel (optional) checkbox label
+     * @param string $text (optional) Text to put after the checkbox
+     * @param mixed $attributes (optional) Either a typical HTML attribute string
+     *              or an associative array
+     * @param mixed $values (optional) Values to pass if checked or not checked
+     */
+    public function __construct($elementName=null, $elementLabel=null, $text=null, $attributes=null, $values=null)
+    {
+        if ($values === null){
+            $values = array(0, 1);
+        }
+
+        if (!empty($attributes['group'])) {
+
+            $this->_group = 'checkboxgroup' . $attributes['group'];
+            unset($attributes['group']);
+            if (is_null($attributes)) {
+                $attributes = array();
+                $attributes['class'] .= " $this->_group";
+            } elseif (is_array($attributes)) {
+                if (isset($attributes['class'])) {
+                    $attributes['class'] .= " $this->_group";
+                } else {
+                    $attributes['class'] = $this->_group;
+                }
+            } elseif ($strpos = stripos($attributes, 'class="')) {
+                $attributes = str_ireplace('class="', 'class="' . $this->_group . ' ', $attributes);
+            } else {
+                $attributes .= ' class="' . $this->_group . '"';
+            }
+        }
+
+        parent::__construct($elementName, $elementLabel, $text, $attributes, $values);
+        $this->_type = 'advcheckbox';
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_advcheckbox($elementName=null, $elementLabel=null, $text=null, $attributes=null, $values=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $text, $attributes, $values);
+    }
+
+    /**
+     * get html for help button
+     *
+     * @return string html for help button
+     */
+    function getHelpButton(){
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Returns HTML for advchecbox form element.
+     *
+     * @return string
+     */
+    function toHtml()
+    {
+        return '<span>' . parent::toHtml() . '</span>';
+    }
+
+    /**
+     * Returns the disabled field. Accessibility: the return "[ ]" from parent
+     * class is not acceptable for screenreader users, and we DO want a label.
+     *
+     * @return string
+     */
+    function getFrozenHtml()
+    {
+        //$this->_generateId();
+        $output = '<input type="checkbox" disabled="disabled" id="'.$this->getAttribute('id').'" ';
+        if ($this->getChecked()) {
+            $output .= 'checked="checked" />'.$this->_getPersistantData();
+        } else {
+            $output .= '/>';
+        }
+        return $output;
+    }
+
+    public function export_for_template(renderer_base $output) {
+        $context = $this->export_for_template_base($output);
+
+        $context['selectedvalue'] = $this->_values[1];
+        $context['deselectedvalue'] = $this->_values[0];
+        $context['frozenvalue'] = $this->getValue();
+        return $context;
+    }
+
+}

lib/form/amd/build/changechecker.min.js

@@ -0,0 +1,53 @@
+define("core_form/changechecker",["exports","core_editor/events","core/str"],(function(_exports,_events,_str){Object.defineProperty(_exports,"__esModule",{value:!0}),_exports.watchFormById=_exports.watchForm=_exports.unWatchForm=_exports.startWatching=_exports.resetFormDirtyStateById=_exports.resetFormDirtyState=_exports.resetAllFormDirtyStates=_exports.markFormSubmitted=_exports.markFormChangedFromNode=_exports.markFormAsDirtyById=_exports.markFormAsDirty=_exports.markAllFormsSubmitted=_exports.markAllFormsAsDirty=_exports.isAnyWatchedFormDirty=_exports.disableAllChecks=void 0;
+/**
+   * This module provides change detection to forms, allowing a browser to warn the user before navigating away if changes
+   * have been made.
+   *
+   * Two flags are stored for each form:
+   * * a 'dirty' flag; and
+   * * a 'submitted' flag.
+   *
+   * When the page is unloaded each watched form is checked. If the 'dirty' flag is set for any form, and the 'submitted'
+   * flag is not set for any form, then a warning is shown.
+   *
+   * The 'dirty' flag is set when any form element is modified within a watched form.
+   * The flag can also be set programatically. This may be required for custom form elements.
+   *
+   * It is not possible to customise the warning message in any modern browser.
+   *
+   * Please note that some browsers have controls on when these alerts may or may not be shown.
+   * See {@link https://developer.mozilla.org/en-US/docs/Web/API/WindowEventHandlers/onbeforeunload} for browser-specific
+   * notes and references.
+   *
+   * @module     core_form/changechecker
+   * @copyright  2021 Andrew Lyons <andrew@nicols.co.uk>
+   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+   * @example <caption>Usage where the FormElement is already held</caption>
+   *
+   * import {watchForm} from 'core_form/changechecker';
+   *
+   * // Fetch the form element somehow.
+   * watchForm(formElement);
+   *
+   * @example <caption>Usage from the child of a form - i.e. an input, button, div, etc.</caption>
+   *
+   * import {watchForm} from 'core_form/changechecker';
+   *
+   * // Watch the form by using a child of it.
+   * watchForm(document.querySelector('input[data-foo="bar"]'););
+   *
+   * @example <caption>Usage from within a template</caption>
+   * <form id="mod_example-entry-{{uniqid}}" ...>
+   *   <!--
+   *
+   *   -->
+   * </form>
+   * {{#js}}
+   * require(['core_form/changechecker'], function(changeChecker) {
+   *     watchFormById('mod_example-entry-{{uniqid}}');
+   * });
+   * {{/js}}
+   */
+let warningString,watchedForms=[],formChangeCheckerDisabled=!1;const getFormFromChild=formChild=>formChild.closest("form"),watchForm=formNode=>{(formNode=getFormFromChild(formNode))&&(isWatchingForm(formNode)||watchedForms.push(formNode))};_exports.watchForm=watchForm;_exports.unWatchForm=formNode=>{watchedForms=watchedForms.filter((watchedForm=>!!watchedForm.contains(formNode)))};const resetAllFormDirtyStates=()=>{watchedForms.forEach((watchedForm=>{watchedForm.dataset.formSubmitted="false",watchedForm.dataset.formDirty="false"}))};_exports.resetAllFormDirtyStates=resetAllFormDirtyStates;const resetFormDirtyState=formNode=>{(formNode=getFormFromChild(formNode))&&(formNode.dataset.formSubmitted="false",formNode.dataset.formDirty="false")};_exports.resetFormDirtyState=resetFormDirtyState;_exports.markAllFormsAsDirty=()=>{watchedForms.forEach((watchedForm=>{watchedForm.dataset.formDirty="true"}))};const markFormAsDirty=formNode=>{(formNode=getFormFromChild(formNode))&&(formNode.dataset.formDirty="true")};_exports.markFormAsDirty=markFormAsDirty;const disableAllChecks=()=>{formChangeCheckerDisabled=!0};_exports.disableAllChecks=disableAllChecks;const isAnyWatchedFormDirty=()=>{if(formChangeCheckerDisabled)return!1;if(watchedForms.some((watchedForm=>"true"===watchedForm.dataset.formSubmitted)))return!1;return!!watchedForms.some((watchedForm=>{if(!watchedForm.isConnected)return!1;if("true"===watchedForm.dataset.formDirty)return!0;if(document.activeElement&&document.activeElement.dataset.propertyIsEnumerable("initialValue")){const isActiveElementWatched=isWatchingForm(document.activeElement)&&!shouldIgnoreChangesForNode(document.activeElement),hasValueChanged=document.activeElement.dataset.initialValue!==document.activeElement.value;if(isActiveElementWatched&&hasValueChanged)return!0}return!1}))||!(void 0===window.tinyMCE||!window.tinyMCE.editors||!window.tinyMCE.editors.some((editor=>editor.isDirty())))};_exports.isAnyWatchedFormDirty=isAnyWatchedFormDirty;const isWatchingForm=target=>watchedForms.some((watchedForm=>watchedForm.contains(target))),shouldIgnoreChangesForNode=target=>!!target.closest(".ignoredirty"),markFormChangedFromNode=changedNode=>{if(changedNode.dataset.formChangeCheckerOverride)return void disableAllChecks();if(!isWatchingForm(changedNode))return;if(shouldIgnoreChangesForNode(changedNode))return;var target;(target=changedNode,watchedForms.find((watchedForm=>watchedForm.contains(target)))).dataset.formDirty="true"};_exports.markFormChangedFromNode=markFormChangedFromNode;const markFormSubmitted=formNode=>{(formNode=getFormFromChild(formNode))&&(formNode.dataset.formSubmitted="true")};_exports.markFormSubmitted=markFormSubmitted;_exports.markAllFormsSubmitted=()=>{watchedForms.forEach((watchedForm=>markFormSubmitted(watchedForm)))};const beforeUnloadHandler=e=>isAnyWatchedFormDirty()&&!M.cfg.behatsiterunning?(e.preventDefault(),e.returnValue=warningString,e.returnValue):(window.removeEventListener("beforeunload",beforeUnloadHandler),null),startWatching=()=>{document.addEventListener("change",(e=>{isWatchingForm(e.target)&&markFormChangedFromNode(e.target)})),document.addEventListener("click",(e=>{if(!e.target.closest("[data-formchangechecker-ignore-submit]"))return;const ownerForm=getFormFromChild(e.target);ownerForm&&(ownerForm.dataset.ignoreSubmission="true")})),document.addEventListener("focusin",(e=>{if(e.target.matches("input, textarea, select")){if(e.target.dataset.propertyIsEnumerable("initialValue"))return;e.target.dataset.initialValue=e.target.value}})),document.addEventListener("submit",(e=>{const formNode=getFormFromChild(e.target);formNode&&(formNode.dataset.ignoreSubmission?formNode.dataset.ignoreSubmission="false":markFormSubmitted(formNode))})),document.addEventListener(_events.eventTypes.editorContentRestored,(e=>{e.target!=document?resetFormDirtyState(e.target):resetAllFormDirtyStates()})),(0,_str.getString)("changesmadereallygoaway","moodle").then((changesMadeString=>{warningString=changesMadeString})).catch(),window.addEventListener("beforeunload",beforeUnloadHandler)};_exports.startWatching=startWatching;_exports.watchFormById=formId=>{watchForm(document.getElementById(formId))};_exports.resetFormDirtyStateById=formId=>{resetFormDirtyState(document.getElementById(formId))};_exports.markFormAsDirtyById=formId=>{markFormAsDirty(document.getElementById(formId))},startWatching()}));
+
+//# sourceMappingURL=changechecker.min.js.map

lib/form/amd/build/choicedropdown.min.js

@@ -0,0 +1,19 @@
+define("core_form/choicedropdown",["exports","core/local/dropdown/status","core_form/changechecker"],(function(_exports,_status,_changechecker){Object.defineProperty(_exports,"__esModule",{value:!0}),_exports.init=void 0;
+/**
+   * Field controller for choicedropdown field.
+   *
+   * @module core_form/choicedropdown
+   * @copyright 2023 Ferran Recio <ferran@moodle.com>
+   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+   */
+const Classes_hidden="d-none";
+/**
+   * Internal form element class.
+   *
+   * @private
+   * @class     FieldController
+   * @copyright  2023 Ferran Recio <ferran@moodle.com>
+   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+   */class FieldController{constructor(elementId){this.elementId=elementId,this.mainSelect=document.getElementById(this.elementId),this.dropdown=(0,_status.getDropdownStatus)('[data-form-controls="'.concat(this.elementId,'"]')),this.dropdown.getElement().classList.remove(Classes_hidden)}addEventListeners(){this.dropdown.getElement().addEventListener("change",this.updateSelect.bind(this)),this.dropdown.getElement().addEventListener("click",(event=>event.preventDefault())),this.mainSelect.addEventListener("change",this.updateDropdown.bind(this));new MutationObserver((mutations=>{mutations.forEach((mutation=>{"attributes"===mutation.type&&"disabled"===mutation.attributeName&&this.updateDropdown()}))})).observe(this.mainSelect,{attributeFilter:["disabled"]})}isDisabled(){var _this$mainSelect;return null===(_this$mainSelect=this.mainSelect)||void 0===_this$mainSelect?void 0:_this$mainSelect.hasAttribute("disabled")}async updateDropdown(){this.dropdown.setButtonDisabled(this.isDisabled()),this.dropdown.getSelectedValue()!=this.mainSelect.value&&this.dropdown.setSelectedValue(this.mainSelect.value)}async updateSelect(){this.dropdown.getSelectedValue()!=this.mainSelect.value&&(this.mainSelect.value=this.dropdown.getSelectedValue(),(0,_changechecker.markFormAsDirty)(this.mainSelect.closest("form")),this.mainSelect.dispatchEvent(new Event("change")))}disableInteractiveDialog(){var _this$mainSelect2;null===(_this$mainSelect2=this.mainSelect)||void 0===_this$mainSelect2||_this$mainSelect2.classList.remove(Classes_hidden);this.dropdown.getElement().classList.add(Classes_hidden)}hasForceDialog(){var _this$mainSelect3;return!(null===(_this$mainSelect3=this.mainSelect)||void 0===_this$mainSelect3||!_this$mainSelect3.dataset.forceDialog)}}_exports.init=elementId=>{const field=new FieldController(elementId);!document.body.classList.contains("behat-site")||field.hasForceDialog()?field.addEventListeners():field.disableInteractiveDialog()}}));
+
+//# sourceMappingURL=choicedropdown.min.js.map

lib/form/amd/build/collapsesections.min.js

@@ -0,0 +1,11 @@
+define("core_form/collapsesections",["exports","jquery","core/pending"],(function(_exports,_jquery,_pending){function _interopRequireDefault(obj){return obj&&obj.__esModule?obj:{default:obj}}
+/**
+   * Collapse or expand all form sections on clicking the expand all / collapse al link.
+   *
+   * @module core_form/collapsesections
+   * @copyright 2021 Bas Brands
+   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+   * @since 4.0
+   */Object.defineProperty(_exports,"__esModule",{value:!0}),_exports.init=void 0,_jquery=_interopRequireDefault(_jquery),_pending=_interopRequireDefault(_pending);const SELECTORS_FORM=".mform",SELECTORS_FORMHEADER=".fheader",SELECTORS_FORMCONTAINER="fieldset > .fcontainer",CLASSES_SHOW="show",CLASSES_COLLAPSED="collapsed",CLASSES_HIDDEN="d-none";_exports.init=collapsesections=>{const pendingPromise=new _pending.default("core_form/collapsesections"),collapsemenu=document.querySelector(collapsesections),formParent=collapsemenu.closest(SELECTORS_FORM),formContainers=formParent.querySelectorAll(SELECTORS_FORMCONTAINER);collapsemenu.addEventListener("keydown",(e=>{"Enter"!==e.key&&" "!==e.key||(e.preventDefault(),collapsemenu.click())}));let formcontainercount=0,expandedcount=0;formContainers.forEach((container=>{container.parentElement.classList.contains(CLASSES_HIDDEN)||formcontainercount++,container.classList.contains(CLASSES_SHOW)&&expandedcount++})),formcontainercount===expandedcount&&(collapsemenu.classList.remove(CLASSES_COLLAPSED),collapsemenu.setAttribute("aria-expanded",!0)),collapsemenu.addEventListener("click",(()=>{let action="hide";collapsemenu.classList.contains(CLASSES_COLLAPSED)&&(action="show"),formContainers.forEach((container=>(0,_jquery.default)(container).collapse(action)))}));const collapseElementIds=[...formParent.querySelectorAll(SELECTORS_FORMHEADER)].map(((element,index)=>(element.id=element.id||"collapseElement-".concat(index),element.id)));collapsemenu.setAttribute("aria-controls",collapseElementIds.join(" ")),(0,_jquery.default)(SELECTORS_FORMCONTAINER).on("hidden.bs.collapse",(()=>{[...formContainers].every((container=>!container.classList.contains(CLASSES_SHOW)))&&(collapsemenu.classList.add(CLASSES_COLLAPSED),collapsemenu.setAttribute("aria-expanded",!1))})),(0,_jquery.default)(SELECTORS_FORMCONTAINER).on("shown.bs.collapse",(()=>{[...formContainers].every((container=>container.classList.contains(CLASSES_SHOW)))&&(collapsemenu.classList.remove(CLASSES_COLLAPSED),collapsemenu.setAttribute("aria-expanded",!0))})),pendingPromise.resolve()}}));
+
+//# sourceMappingURL=collapsesections.min.js.map

lib/form/amd/build/configtext_maxlength.min.js

@@ -0,0 +1,3 @@
+define("core_form/configtext_maxlength",["exports","core/str","core/templates","core/notification","core/prefetch"],(function(_exports,_str,_templates,_notification,_prefetch){function _interopRequireDefault(obj){return obj&&obj.__esModule?obj:{default:obj}}Object.defineProperty(_exports,"__esModule",{value:!0}),_exports.init=void 0,_templates=_interopRequireDefault(_templates),_notification=_interopRequireDefault(_notification);let registered=!1;_exports.init=()=>{registered||((0,_prefetch.prefetchStrings)("core",["maximumchars"]),(0,_prefetch.prefetchTemplates)(["core_form/setting_validation_failure"]),registered=!0,document.addEventListener("input",(e=>{const maxLengthField=e.target.closest("[data-validation-max-length]");if(maxLengthField)if(maxLengthField.value.length>maxLengthField.dataset.validationMaxLength)maxLengthField.form.addEventListener("submit",submissionCheck),(0,_str.get_string)("maximumchars","core",maxLengthField.dataset.validationMaxLength).then((errorMessage=>_templates.default.renderForPromise("core_form/setting_validation_failure",{fieldid:maxLengthField.id,message:errorMessage}))).then((errorTemplate=>{if(!maxLengthField.dataset.validationFailureId){const formWrapper=maxLengthField.closest(".form-text");_templates.default.prependNodeContents(formWrapper,errorTemplate.html,errorTemplate.js),maxLengthField.dataset.validationFailureId="maxlength_error_".concat(maxLengthField.id),updateSubmitButton()}})).then((()=>{maxLengthField.setAttribute("aria-invalid",!0);const errorField=document.getElementById(maxLengthField.dataset.validationFailureId);errorField&&errorField.setAttribute("aria-describedby",maxLengthField.id)})).catch(_notification.default.exception);else{const validationMessage=document.getElementById(maxLengthField.dataset.validationFailureId);validationMessage&&(validationMessage.parentElement.remove(),delete maxLengthField.dataset.validationFailureId,maxLengthField.removeAttribute("aria-invalid"),updateSubmitButton())}})))};const submissionCheck=e=>{const maxLengthFields=e.target.querySelectorAll("[data-validation-max-length]");Array.from(maxLengthFields).some((maxLengthField=>maxLengthField.value.length>maxLengthField.dataset.validationMaxLength&&(e.preventDefault(),maxLengthField.focus(),!0)))},updateSubmitButton=()=>{const shouldDisable=document.querySelector("form#adminsettings .error");document.querySelector('form#adminsettings button[type="submit"]').disabled=!!shouldDisable}}));
+
+//# sourceMappingURL=configtext_maxlength.min.js.map

lib/form/amd/build/defaultcustom.min.js

@@ -0,0 +1,11 @@
+/**
+ * Functionality for the form element defaultcustom
+ *
+ * @module     core_form/defaultcustom
+ * @copyright  2017 Marina Glancy
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @since      3.3
+ */
+define("core_form/defaultcustom",["jquery"],(function($){$("body").on("change","input[data-defaultcustom=true]",(function(event){var element=$(event.target),defaultvalue=JSON.parse(element.attr("data-defaultvalue")),customvalue=JSON.parse(element.attr("data-customvalue")),type=element.attr("data-type"),form=element.closest("form"),elementName=element.attr("name").replace(/\[customize\]$/,"[value]"),newvalue=element.prop("checked")?customvalue:defaultvalue;"text"===type?form.find('[name="'+elementName+'"]').val(newvalue):"date_selector"===type?(form.find('[name="'+elementName+'[day]"]').val(newvalue.day),form.find('[name="'+elementName+'[month]"]').val(newvalue.month),form.find('[name="'+elementName+'[year]"]').val(newvalue.year)):"date_time_selector"===type&&(form.find('[name="'+elementName+'[day]"]').val(newvalue.day),form.find('[name="'+elementName+'[month]"]').val(newvalue.month),form.find('[name="'+elementName+'[year]"]').val(newvalue.year),form.find('[name="'+elementName+'[hour]"]').val(newvalue.hour),form.find('[name="'+elementName+'[minute]"]').val(newvalue.minute))}))}));
+
+//# sourceMappingURL=defaultcustom.min.js.map

lib/form/amd/build/defaultcustom.min.js.map

@@ -0,0 +1 @@
+{"version":3,"file":"defaultcustom.min.js","sources":["../src/defaultcustom.js"],"sourcesContent":["// This file is part of Moodle - http://moodle.org/\n//\n// Moodle is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n//\n// Moodle is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n//\n// You should have received a copy of the GNU General Public License\n// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.\n\n/**\n * Functionality for the form element defaultcustom\n *\n * @module     core_form/defaultcustom\n * @copyright  2017 Marina Glancy\n * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later\n * @since      3.3\n */\ndefine(['jquery'], function($) {\n    var onChangeSelect = function(event) {\n        var element = $(event.target),\n            defaultvalue = JSON.parse(element.attr('data-defaultvalue')),\n            customvalue = JSON.parse(element.attr('data-customvalue')),\n            type = element.attr('data-type'),\n            form = element.closest('form'),\n            elementName = element.attr('name').replace(/\\[customize\\]$/, '[value]'),\n            newvalue = element.prop('checked') ? customvalue : defaultvalue;\n\n        if (type === 'text') {\n            form.find('[name=\"' + elementName + '\"]').val(newvalue);\n        } else if (type === 'date_selector') {\n            form.find('[name=\"' + elementName + '[day]\"]').val(newvalue.day);\n            form.find('[name=\"' + elementName + '[month]\"]').val(newvalue.month);\n            form.find('[name=\"' + elementName + '[year]\"]').val(newvalue.year);\n        } else if (type === 'date_time_selector') {\n            form.find('[name=\"' + elementName + '[day]\"]').val(newvalue.day);\n            form.find('[name=\"' + elementName + '[month]\"]').val(newvalue.month);\n            form.find('[name=\"' + elementName + '[year]\"]').val(newvalue.year);\n            form.find('[name=\"' + elementName + '[hour]\"]').val(newvalue.hour);\n            form.find('[name=\"' + elementName + '[minute]\"]').val(newvalue.minute);\n        }\n    };\n\n    var selector = 'input[data-defaultcustom=true]';\n    $('body').on('change', selector, onChangeSelect);\n});\n"],"names":["define","$","on","event","element","target","defaultvalue","JSON","parse","attr","customvalue","type","form","closest","elementName","replace","newvalue","prop","find","val","day","month","year","hour","minute"],"mappings":";;;;;;;;AAuBAA,iCAAO,CAAC,WAAW,SAASC,GA0BxBA,EAAE,QAAQC,GAAG,SADE,kCAxBM,SAASC,WACtBC,QAAUH,EAAEE,MAAME,QAClBC,aAAeC,KAAKC,MAAMJ,QAAQK,KAAK,sBACvCC,YAAcH,KAAKC,MAAMJ,QAAQK,KAAK,qBACtCE,KAAOP,QAAQK,KAAK,aACpBG,KAAOR,QAAQS,QAAQ,QACvBC,YAAcV,QAAQK,KAAK,QAAQM,QAAQ,iBAAkB,WAC7DC,SAAWZ,QAAQa,KAAK,WAAaP,YAAcJ,aAE1C,SAATK,KACAC,KAAKM,KAAK,UAAYJ,YAAc,MAAMK,IAAIH,UAC9B,kBAATL,MACPC,KAAKM,KAAK,UAAYJ,YAAc,WAAWK,IAAIH,SAASI,KAC5DR,KAAKM,KAAK,UAAYJ,YAAc,aAAaK,IAAIH,SAASK,OAC9DT,KAAKM,KAAK,UAAYJ,YAAc,YAAYK,IAAIH,SAASM,OAC7C,uBAATX,OACPC,KAAKM,KAAK,UAAYJ,YAAc,WAAWK,IAAIH,SAASI,KAC5DR,KAAKM,KAAK,UAAYJ,YAAc,aAAaK,IAAIH,SAASK,OAC9DT,KAAKM,KAAK,UAAYJ,YAAc,YAAYK,IAAIH,SAASM,MAC7DV,KAAKM,KAAK,UAAYJ,YAAc,YAAYK,IAAIH,SAASO,MAC7DX,KAAKM,KAAK,UAAYJ,YAAc,cAAcK,IAAIH,SAASQ"}

lib/form/amd/build/encryptedpassword.min.js

@@ -0,0 +1,11 @@
+define("core_form/encryptedpassword",["exports"],(function(_exports){Object.defineProperty(_exports,"__esModule",{value:!0}),_exports.EncryptedPassword=void 0;
+/**
+   * Encrypted password functionality.
+   *
+   * @module core_form/encryptedpassword
+   * @copyright 2019 The Open University
+   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+   */
+const EncryptedPassword=function(elementId){const wrapper=document.querySelector('div[data-encryptedpasswordid="'+elementId+'"]');this.spanOrLink=wrapper.querySelector("span, a"),this.input=wrapper.querySelector("input"),this.editButtonOrLink=wrapper.querySelector("button[data-editbutton], a"),this.cancelButton=wrapper.querySelector("button[data-cancelbutton]");var editHandler=e=>{e.stopImmediatePropagation(),e.preventDefault(),this.startEditing(!0)};this.editButtonOrLink.addEventListener("click",editHandler),"A"===this.editButtonOrLink.nodeName&&wrapper.parentElement.previousElementSibling.querySelector("label").addEventListener("click",editHandler),this.cancelButton.addEventListener("click",(e=>{e.stopImmediatePropagation(),e.preventDefault(),this.cancelEditing()})),"y"===wrapper.dataset.novalue&&(this.startEditing(!1),this.cancelButton.style.display="none")};_exports.EncryptedPassword=EncryptedPassword,EncryptedPassword.prototype.startEditing=function(moveFocus){this.input.style.display="inline",this.input.disabled=!1,this.spanOrLink.style.display="none",this.editButtonOrLink.style.display="none",this.cancelButton.style.display="inline";const id=this.editButtonOrLink.id;this.editButtonOrLink.removeAttribute("id"),this.input.id=id,moveFocus&&this.input.focus()},EncryptedPassword.prototype.cancelEditing=function(){this.input.style.display="none",this.input.value="",this.input.disabled=!0,this.spanOrLink.style.display="inline",this.editButtonOrLink.style.display="inline",this.cancelButton.style.display="none";const id=this.input.id;this.input.removeAttribute("id"),this.editButtonOrLink.id=id}}));
+
+//# sourceMappingURL=encryptedpassword.min.js.map

lib/form/amd/build/events.min.js

@@ -0,0 +1,19 @@
+define("core_form/events",["exports","core/str","core/event_dispatcher","jquery","core/yui"],(function(_exports,_str,_event_dispatcher,_jquery,_yui){function _interopRequireDefault(obj){return obj&&obj.__esModule?obj:{default:obj}}
+/**
+   * Javascript events for the `core_form` subsystem.
+   *
+   * @module core_form/events
+   * @copyright 2021 Huong Nguyen <huongnv13@gmail.com>
+   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+   * @since 3.10
+   *
+   * @example <caption>Example of listening to a form event.</caption>
+   * import {eventTypes as formEventTypes} from 'core_form/events';
+   *
+   * document.addEventListener(formEventTypes.formSubmittedByJavascript, e => {
+   *     window.console.log(e.target); // The form that was submitted.
+   *     window.console.log(e.detail.skipValidation); // Whether form validation was skipped.
+   * });
+   */let changesMadeString;Object.defineProperty(_exports,"__esModule",{value:!0}),_exports.types=_exports.triggerUploadStarted=_exports.triggerUploadCompleted=_exports.notifyUploadStarted=_exports.notifyUploadCompleted=_exports.notifyUploadChanged=_exports.notifyFormSubmittedByJavascript=_exports.notifyFormError=_exports.notifyFieldValidationFailure=_exports.notifyFieldStructureChanged=_exports.eventTypes=void 0,_jquery=_interopRequireDefault(_jquery),_yui=_interopRequireDefault(_yui);const changesMadeCheck=e=>{e&&(e.returnValue=changesMadeString)},eventTypes={formError:"core_form/error",formSubmittedByJavascript:"core_form/submittedByJavascript",formFieldValidationFailed:"core_form/fieldValidationFailed",uploadStarted:"core_form/uploadStarted",uploadCompleted:"core_form/uploadCompleted",uploadChanged:"core_form/uploadChanged",fieldStructureChanged:"core_form/fieldStructureChanged"};_exports.eventTypes=eventTypes;_exports.notifyFormError=field=>(0,_event_dispatcher.dispatchEvent)(eventTypes.formError,{},field);_exports.notifyFormSubmittedByJavascript=function(form){let skipValidation=arguments.length>1&&void 0!==arguments[1]&&arguments[1],fallbackHandled=arguments.length>2&&void 0!==arguments[2]&&arguments[2];skipValidation&&(window.skipClientValidation=!0);const customEvent=(0,_event_dispatcher.dispatchEvent)(eventTypes.formSubmittedByJavascript,{skipValidation:skipValidation,fallbackHandled:fallbackHandled},form);return skipValidation&&(window.skipClientValidation=!1),customEvent};_exports.notifyFieldValidationFailure=(field,message)=>(0,_event_dispatcher.dispatchEvent)(eventTypes.formFieldValidationFailed,{message:message},field,{cancelable:!0});const notifyUploadStarted=async elementId=>(changesMadeString=await(0,_str.getString)("changesmadereallygoaway","moodle"),window.addEventListener("beforeunload",changesMadeCheck),(0,_event_dispatcher.dispatchEvent)(eventTypes.uploadStarted,{},document.getElementById(elementId),{bubbles:!0,cancellable:!1}));_exports.notifyUploadStarted=notifyUploadStarted;const notifyUploadCompleted=elementId=>(window.removeEventListener("beforeunload",changesMadeCheck),(0,_event_dispatcher.dispatchEvent)(eventTypes.uploadCompleted,{},document.getElementById(elementId),{bubbles:!0,cancellable:!1}));_exports.notifyUploadCompleted=notifyUploadCompleted;const triggerUploadStarted=notifyUploadStarted;_exports.triggerUploadStarted=triggerUploadStarted;const triggerUploadCompleted=notifyUploadCompleted;_exports.triggerUploadCompleted=triggerUploadCompleted;_exports.types={uploadStarted:"core_form/uploadStarted",uploadCompleted:"core_form/uploadCompleted"};let legacyEventsRegistered=!1;legacyEventsRegistered||(_yui.default.use("event","moodle-core-event",(()=>{document.addEventListener(eventTypes.formError,(e=>{const element=_yui.default.one(e.target),formElement=_yui.default.one(e.target.closest("form"));_yui.default.Global.fire(M.core.globalEvents.FORM_ERROR,{formid:formElement.generateID(),elementid:element.generateID()})})),document.addEventListener(eventTypes.formSubmittedByJavascript,(e=>{if(e.detail.fallbackHandled)return;e.skipValidation&&(window.skipClientValidation=!0);const form=_yui.default.one(e.target);form.fire(M.core.event.FORM_SUBMIT_AJAX,{currentTarget:form,fallbackHandled:!0}),e.skipValidation&&(window.skipClientValidation=!1)}))})),document.addEventListener(eventTypes.formFieldValidationFailed,(e=>{const legacyEvent=_jquery.default.Event("core_form-field-validation");(0,_jquery.default)(e.target).trigger(legacyEvent,e.detail.message)})),legacyEventsRegistered=!0);_exports.notifyUploadChanged=elementId=>(0,_event_dispatcher.dispatchEvent)(eventTypes.uploadChanged,{},document.getElementById(elementId),{bubbles:!0,cancellable:!1});_exports.notifyFieldStructureChanged=elementId=>(0,_event_dispatcher.dispatchEvent)(eventTypes.fieldStructureChanged,{},document.getElementById(elementId),{bubbles:!0,cancellable:!1})}));
+
+//# sourceMappingURL=events.min.js.map

lib/form/amd/build/passwordunmask.min.js

@@ -0,0 +1,11 @@
+/**
+ * Password Unmask functionality.
+ *
+ * @module     core_form/passwordunmask
+ * @copyright  2016 Andrew Nicols <andrew@nicols.co.uk>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @since      3.2
+ */
+define("core_form/passwordunmask",["jquery","core/templates"],(function($,Template){var PasswordUnmask=function(elementid){this.wrapperSelector='[data-passwordunmask="wrapper"][data-passwordunmaskid="'+elementid+'"]',this.wrapper=$(this.wrapperSelector),this.editorSpace=this.wrapper.find('[data-passwordunmask="editor"]'),this.editLink=this.wrapper.find('a[data-passwordunmask="edit"]'),this.editInstructions=this.wrapper.find('[data-passwordunmask="instructions"]'),this.displayValue=this.wrapper.find('[data-passwordunmask="displayvalue"]'),this.inputFieldLabel=$('label[for="'+elementid+'"]'),this.inputField=this.editorSpace.find(document.getElementById(elementid)),this.inputField.addClass("d-none"),this.inputField.removeClass("hiddenifjs"),this.editInstructions.attr("id")||this.editInstructions.attr("id",elementid+"_instructions"),this.editInstructions.hide(),this.setDisplayValue(),this.addListeners()};return PasswordUnmask.prototype.addListeners=function(){return this.wrapper.on("click keypress",'[data-passwordunmask="edit"]',$.proxy((function(e){"keypress"===e.type&&13!==e.keyCode||(e.stopImmediatePropagation(),e.preventDefault(),this.isEditing()?"click"===e.type||$(e.relatedTarget).is(":input")?this.turnEditingOff(!1):this.turnEditingOff(!0):this.turnEditingOn())}),this)),this.wrapper.on("click keypress",'[data-passwordunmask="unmask"]',$.proxy((function(e){"keypress"===e.type&&13!==e.keyCode||(e.stopImmediatePropagation(),e.preventDefault(),this.wrapper.data("unmasked",!this.wrapper.data("unmasked")),this.setDisplayValue())}),this)),this.wrapper.on("keydown","input",$.proxy((function(e){"keydown"===e.type&&13!==e.keyCode||(e.stopImmediatePropagation(),e.preventDefault(),this.turnEditingOff(!0))}),this)),this.inputFieldLabel.on("click",$.proxy((function(e){e.preventDefault(),this.turnEditingOn()}),this)),this},PasswordUnmask.prototype.checkFocusOut=function(e){this.isEditing()&&window.setTimeout($.proxy((function(){var relatedTarget=e.relatedTarget||document.activeElement;this.wrapper.has($(relatedTarget)).length||this.turnEditingOff(!$(relatedTarget).is(":input,a"))}),this),100)},PasswordUnmask.prototype.passwordVisible=function(){return!!this.wrapper.data("unmasked")},PasswordUnmask.prototype.isEditing=function(){return this.inputField.hasClass("d-inline-block")},PasswordUnmask.prototype.turnEditingOn=function(){var value=this.getDisplayValue();return this.passwordVisible()?this.inputField.attr("type","text"):this.inputField.attr("type","password"),this.inputField.val(value),this.inputField.attr("size",this.inputField.attr("data-size")),this.inputField.addClass("d-inline-block"),this.editInstructions.length&&(this.inputField.attr("aria-describedby",this.editInstructions.attr("id")),this.editInstructions.show()),this.wrapper.attr("data-passwordunmask-visible",1),this.editLink.hide(),this.inputField.focus().select(),$("body").on("focusout",this.wrapperSelector,$.proxy(this.checkFocusOut,this)),this},PasswordUnmask.prototype.turnEditingOff=function(focusOnEditLink){$("body").off("focusout",this.wrapperSelector,this.checkFocusOut);var value=this.getDisplayValue();return this.inputField.attr("aria-describedby",null),this.inputField.val(value),this.inputField.removeClass("d-inline-block"),this.editInstructions.hide(),this.wrapper.removeAttr("data-passwordunmask-visible"),this.inputField.removeAttr("size"),this.editLink.show(),this.setDisplayValue(),focusOnEditLink&&this.editLink.focus(),this},PasswordUnmask.prototype.getDisplayValue=function(){return this.inputField.val()},PasswordUnmask.prototype.setDisplayValue=function(){var value=this.getDisplayValue();return this.isEditing()&&(this.wrapper.data("unmasked")?this.inputField.attr("type","text"):this.inputField.attr("type","password"),this.inputField.val(value)),value&&this.wrapper.data("unmasked")?this.displayValue.text(value):(value||(value=""),Template.render("core_form/element-passwordunmask-fill",{element:{frozen:this.inputField.is("[readonly]"),value:value,valuechars:value.split("")}}).done($.proxy((function(html,js){this.displayValue.html(html),Template.runTemplateJS(js)}),this))),this},PasswordUnmask}));
+
+//# sourceMappingURL=passwordunmask.min.js.map

lib/form/amd/build/showadvanced.min.js

@@ -0,0 +1,10 @@
+/**
+ * A class to help show and hide advanced form content.
+ *
+ * @module     core_form/showadvanced
+ * @copyright  2016 Damyon Wiese <damyon@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+define("core_form/showadvanced",["jquery","core/log","core/str","core/notification"],(function($,Log,Strings,Notification){var SELECTORS_FIELDSETCONTAINSADVANCED="fieldset.containsadvancedelements",SELECTORS_DIVFITEMADVANCED="div.fitem.advanced",SELECTORS_DIVADVANCEDSECTION="div#form-advanced-div",SELECTORS_MORELESSLINK="fieldset.containsadvancedelements .moreless-toggler",CSS_SHOW="show",CSS_MORELESSACTIONS="moreless-actions",CSS_MORELESSTOGGLER="moreless-toggler",CSS_SHOWLESS="moreless-less",WRAPPERS_FITEM='<div class="fitem"></div>',WRAPPERS_FELEMENT='<div class="felement"></div>',WRAPPERS_ADVANCEDDIV='<div id="form-advanced-div"></div>',uniqIdSeed=0,ShowAdvanced=function(id){this.id=id;var form=$(document.getElementById(id));this.enhanceForm(form)};return ShowAdvanced.prototype.id="",ShowAdvanced.prototype.enhanceForm=function(form){return form.find(SELECTORS_FIELDSETCONTAINSADVANCED).each(function(index,item){this.enhanceFieldset($(item))}.bind(this)),form.on("click",SELECTORS_MORELESSLINK,this.switchState),form.on("keydown",SELECTORS_MORELESSLINK,function(e){return 13!=e.which&&32!=e.which||this.switchState(e)}.bind(this)),this},ShowAdvanced.prototype.generateId=function(node){var id=node.prop("id");return void 0===id&&(id="showadvancedid-"+uniqIdSeed++,node.prop("id",id)),id},ShowAdvanced.prototype.enhanceFieldset=function(fieldset){var statuselement=$("input[name=mform_showmore_"+fieldset.prop("id")+"]");return statuselement.length?(Strings.get_strings([{key:"showmore",component:"core_form"},{key:"showless",component:"core_form"}]).then(function(results){var showmore=results[0],showless=results[1],morelesslink=$('<a href="#"></a>');morelesslink.addClass(CSS_MORELESSTOGGLER),"0"===statuselement.val()?(morelesslink.html(showmore),morelesslink.attr("aria-expanded","false")):(morelesslink.html(showless),morelesslink.attr("aria-expanded","true"),morelesslink.addClass(CSS_SHOWLESS),fieldset.find(SELECTORS_DIVFITEMADVANCED).addClass(CSS_SHOW));var idlist=[];fieldset.find(SELECTORS_DIVFITEMADVANCED).each(function(index,node){idlist[idlist.length]=this.generateId($(node))}.bind(this)),morelesslink.attr("role","button"),morelesslink.attr("aria-controls","form-advanced-div");var formadvancedsection=$(WRAPPERS_ADVANCEDDIV);fieldset.find(SELECTORS_DIVFITEMADVANCED).wrapAll(formadvancedsection);var fitem=$(WRAPPERS_FITEM);fitem.addClass(CSS_MORELESSACTIONS);var felement=$(WRAPPERS_FELEMENT);return felement.append(morelesslink),fitem.append(felement),fieldset.find(SELECTORS_DIVADVANCEDSECTION).before(fitem),!0}.bind(this)).fail(Notification.exception),this):(Log.debug("M.form.showadvanced::processFieldset was called on an fieldset without a status field: '"+fieldset.prop("id")+"'"),this)},ShowAdvanced.prototype.switchState=function(e){return e.preventDefault(),Strings.get_strings([{key:"showmore",component:"core_form"},{key:"showless",component:"core_form"}]).then((function(results){var showmore=results[0],showless=results[1],fieldset=$(e.target).closest(SELECTORS_FIELDSETCONTAINSADVANCED);fieldset.find(SELECTORS_DIVFITEMADVANCED).toggleClass(CSS_SHOW);var statuselement=$("input[name=mform_showmore_"+fieldset.prop("id")+"]");return"0"===statuselement.val()?(statuselement.val(1),$(e.target).addClass(CSS_SHOWLESS),$(e.target).html(showless),$(e.target).attr("aria-expanded","true")):(statuselement.val(0),$(e.target).removeClass(CSS_SHOWLESS),$(e.target).html(showmore),$(e.target).attr("aria-expanded","false")),!0})).fail(Notification.exception),this},{init:function(formid){return new ShowAdvanced(formid)}}}));
+
+//# sourceMappingURL=showadvanced.min.js.map

lib/form/amd/build/submit.min.js

@@ -0,0 +1,13 @@
+define("core_form/submit",["exports","core_form/events"],(function(_exports,_events){Object.defineProperty(_exports,"__esModule",{value:!0}),_exports.init=void 0;
+/**
+   * Submit button JavaScript. All submit buttons will be automatically disabled once the form is
+   * submitted, unless that submission results in an error/cancelling the submit.
+   *
+   * @module core_form/submit
+   * @copyright 2019 The Open University
+   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+   * @since 3.8
+   */
+let cookieListener=0;const cookieListeningButtons=[];let currentUploadCount=0;const uploadListeningButtons=[];let uploadListenersRegistered=!1;const getCookieName=()=>"moodledownload_"+M.cfg.sesskey,clearDownloadCookie=()=>{document.cookie=encodeURIComponent(getCookieName())+"=deleted; expires="+new Date(0).toUTCString()},checkUploadCount=()=>{currentUploadCount?uploadListeningButtons.forEach((button=>{button.disabled=!0})):uploadListeningButtons.forEach((button=>{button.disabled=!1}))};_exports.init=elementId=>{const button=document.getElementById(elementId);null!==button&&(button.disabled||uploadListeningButtons.push(button),uploadListenersRegistered||(document.addEventListener(_events.eventTypes.uploadStarted,(()=>{currentUploadCount++,checkUploadCount()})),document.addEventListener(_events.eventTypes.uploadCompleted,(()=>{currentUploadCount--,checkUploadCount()})),uploadListenersRegistered=!0),"off"!==button.form.dataset.doubleSubmitProtection&&button.form.addEventListener("submit",(function(event){const disableAction=function(){event.defaultPrevented||button.disabled||(button.disabled=!0,clearDownloadCookie(),(button=>{cookieListeningButtons.push(button),cookieListener||(cookieListener=setInterval((()=>{2==document.cookie.split(getCookieName()+"=").length&&(clearDownloadCookie(),clearInterval(cookieListener),cookieListener=0,cookieListeningButtons.forEach((button=>{button.disabled=!1})))}),500))})(button))};window.addEventListener("beforeunload",disableAction),setTimeout((function(){window.removeEventListener("beforeunload",disableAction)}),1)}),!1))}}));
+
+//# sourceMappingURL=submit.min.js.map

lib/form/amd/build/util.min.js

@@ -0,0 +1,3 @@
+define("core_form/util",["exports"],(function(_exports){Object.defineProperty(_exports,"__esModule",{value:!0}),_exports.serialize=void 0;const serialize=function(data){let prefix=arguments.length>1&&void 0!==arguments[1]?arguments[1]:"";return[...Object.entries(data).map((_ref=>{let[index,value]=_ref;const key=prefix?"".concat(prefix,"[").concat(index,"]"):index;return null!==value&&"object"==typeof value?serialize(value,key):"".concat(key,"=").concat(encodeURIComponent(value))}))].join("&")};_exports.serialize=serialize}));
+
+//# sourceMappingURL=util.min.js.map

lib/form/amd/build/util.min.js.map

@@ -0,0 +1 @@
+{"version":3,"file":"util.min.js","sources":["../src/util.js"],"sourcesContent":["// This file is part of Moodle - http://moodle.org/\n//\n// Moodle is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n//\n// Moodle is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n//\n// You should have received a copy of the GNU General Public License\n// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.\n\n/**\n * Serialize form values into a string.\n *\n * This must be used instead of URLSearchParams, which does not correctly encode nested values such as arrays.\n *\n * @param {Object} data The form values to serialize\n * @param {string} prefix The prefix to use for key names\n * @returns {string}\n */\nexport const serialize = (data, prefix = '') => [\n    ...Object.entries(data).map(([index, value]) => {\n        const key = prefix ? `${prefix}[${index}]` : index;\n        return (value !== null && typeof value === \"object\") ? serialize(value, key) : `${key}=${encodeURIComponent(value)}`;\n    })\n].join(\"&\");\n"],"names":["serialize","data","prefix","Object","entries","map","_ref","index","value","key","encodeURIComponent","join"],"mappings":"gJAwBaA,UAAY,SAACC,UAAMC,8DAAS,SAAO,IACzCC,OAAOC,QAAQH,MAAMI,KAAIC,WAAEC,MAAOC,kBAC3BC,IAAMP,iBAAYA,mBAAUK,WAAWA,aAC3B,OAAVC,OAAmC,iBAAVA,MAAsBR,UAAUQ,MAAOC,eAAUA,gBAAOC,mBAAmBF,YAElHG,KAAK"}

lib/form/amd/src/changechecker.js

@@ -0,0 +1,516 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * This module provides change detection to forms, allowing a browser to warn the user before navigating away if changes
+ * have been made.
+ *
+ * Two flags are stored for each form:
+ * * a 'dirty' flag; and
+ * * a 'submitted' flag.
+ *
+ * When the page is unloaded each watched form is checked. If the 'dirty' flag is set for any form, and the 'submitted'
+ * flag is not set for any form, then a warning is shown.
+ *
+ * The 'dirty' flag is set when any form element is modified within a watched form.
+ * The flag can also be set programatically. This may be required for custom form elements.
+ *
+ * It is not possible to customise the warning message in any modern browser.
+ *
+ * Please note that some browsers have controls on when these alerts may or may not be shown.
+ * See {@link https://developer.mozilla.org/en-US/docs/Web/API/WindowEventHandlers/onbeforeunload} for browser-specific
+ * notes and references.
+ *
+ * @module     core_form/changechecker
+ * @copyright  2021 Andrew Lyons <andrew@nicols.co.uk>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @example <caption>Usage where the FormElement is already held</caption>
+ *
+ * import {watchForm} from 'core_form/changechecker';
+ *
+ * // Fetch the form element somehow.
+ * watchForm(formElement);
+ *
+ * @example <caption>Usage from the child of a form - i.e. an input, button, div, etc.</caption>
+ *
+ * import {watchForm} from 'core_form/changechecker';
+ *
+ * // Watch the form by using a child of it.
+ * watchForm(document.querySelector('input[data-foo="bar"]'););
+ *
+ * @example <caption>Usage from within a template</caption>
+ * <form id="mod_example-entry-{{uniqid}}" ...>
+ *   <!--
+ *
+ *   -->
+ * </form>
+ * {{#js}}
+ * require(['core_form/changechecker'], function(changeChecker) {
+ *     watchFormById('mod_example-entry-{{uniqid}}');
+ * });
+ * {{/js}}
+ */
+
+import {eventTypes} from 'core_editor/events';
+import {getString} from 'core/str';
+
+/**
+ * @property {Bool} initialised Whether the change checker has been initialised
+ * @private
+ */
+let initialised = false;
+
+/**
+ * @property {String} warningString The warning string to show on form change failure
+ * @private
+ */
+let warningString;
+
+/**
+ * @property {Array} watchedForms The list of watched forms
+ * @private
+ */
+let watchedForms = [];
+
+/**
+ * @property {Bool} formChangeCheckerDisabled Whether the form change checker has been actively disabled
+ * @private
+ */
+let formChangeCheckerDisabled = false;
+
+/**
+ * Get the nearest form element from a child element.
+ *
+ * @param {HTMLElement} formChild
+ * @returns {HTMLFormElement|null}
+ * @private
+ */
+const getFormFromChild = formChild => formChild.closest('form');
+
+/**
+ * Watch the specified form for changes.
+ *
+ * @method
+ * @param   {HTMLElement} formNode
+ */
+export const watchForm = formNode => {
+    // Normalise the formNode.
+    formNode = getFormFromChild(formNode);
+
+    if (!formNode) {
+         // No form found.
+         return;
+    }
+
+    if (isWatchingForm(formNode)) {
+        // This form is already watched.
+        return;
+    }
+
+    watchedForms.push(formNode);
+};
+
+/**
+ * Stop watching the specified form for changes.
+ *
+ * If the form was not watched, then no change is made.
+ *
+ * A child of the form may be passed instead.
+ *
+ * @method
+ * @param   {HTMLElement} formNode
+ * @example <caption>Stop watching a form for changes</caption>
+ * import {unWatchForm} from 'core_form/changechecker';
+ *
+ * // ...
+ * document.addEventListener('click', e => {
+ *     if (e.target.closest('[data-action="changePage"]')) {
+ *         unWatchForm(e.target);
+ *     }
+ * });
+ */
+export const unWatchForm = formNode => {
+    watchedForms = watchedForms.filter(watchedForm => !!watchedForm.contains(formNode));
+};
+
+/**
+ * Reset the 'dirty' flag for all watched forms.
+ *
+ * If a form was previously marked as 'dirty', then this flag will be cleared and when the page is unloaded no warning
+ * will be shown.
+ *
+ * @method
+ */
+export const resetAllFormDirtyStates = () => {
+    watchedForms.forEach(watchedForm => {
+        watchedForm.dataset.formSubmitted = "false";
+        watchedForm.dataset.formDirty = "false";
+    });
+};
+
+/**
+ * Reset the 'dirty' flag of the specified form.
+ *
+ * @method
+ * @param   {HTMLElement} formNode
+ */
+export const resetFormDirtyState = formNode => {
+    formNode = getFormFromChild(formNode);
+
+    if (!formNode) {
+         return;
+    }
+
+    formNode.dataset.formSubmitted = "false";
+    formNode.dataset.formDirty = "false";
+};
+
+/**
+ * Mark all forms as dirty.
+ *
+ * This function is only for backwards-compliance with the old YUI module and should not be used in any other situation.
+ * It will be removed in Moodle 4.4.
+ *
+ * @method
+ */
+export const markAllFormsAsDirty = () => {
+    watchedForms.forEach(watchedForm => {
+        watchedForm.dataset.formDirty = "true";
+    });
+};
+
+/**
+ * Mark a specific form as dirty.
+ *
+ * This behaviour may be required for custom form elements which are not caught by the standard change listeners.
+ *
+ * @method
+ * @param   {HTMLElement} formNode
+ */
+export const markFormAsDirty = formNode => {
+    formNode = getFormFromChild(formNode);
+
+    if (!formNode) {
+         return;
+    }
+
+    // Mark it as dirty.
+    formNode.dataset.formDirty = "true";
+};
+
+/**
+ * Actively disable the form change checker.
+ *
+ * Please note that it cannot be re-enabled once disabled.
+ *
+ * @method
+ */
+export const disableAllChecks = () => {
+    formChangeCheckerDisabled = true;
+};
+
+/**
+ * Check whether any watched from is dirty.
+ *
+ * @method
+ * @returns {Bool}
+ */
+export const isAnyWatchedFormDirty = () => {
+    if (formChangeCheckerDisabled) {
+        // The form change checker is disabled.
+        return false;
+    }
+
+    const hasSubmittedForm = watchedForms.some(watchedForm => watchedForm.dataset.formSubmitted === "true");
+    if (hasSubmittedForm) {
+        // Do not warn about submitted forms, ever.
+        return false;
+    }
+
+    const hasDirtyForm = watchedForms.some(watchedForm => {
+        if (!watchedForm.isConnected) {
+            // The watched form is not connected to the DOM.
+            return false;
+        }
+
+        if (watchedForm.dataset.formDirty === "true") {
+            // The form has been marked as dirty.
+            return true;
+        }
+
+        // Elements currently holding focus will not have triggered change detection.
+        // Check whether the value matches the original value upon form load.
+        if (document.activeElement && document.activeElement.dataset.propertyIsEnumerable('initialValue')) {
+            const isActiveElementWatched = isWatchingForm(document.activeElement)
+                && !shouldIgnoreChangesForNode(document.activeElement);
+            const hasValueChanged = document.activeElement.dataset.initialValue !== document.activeElement.value;
+
+            if (isActiveElementWatched && hasValueChanged) {
+                return true;
+            }
+        }
+
+        return false;
+    });
+
+    if (hasDirtyForm) {
+        // At least one form is dirty.
+        return true;
+    }
+
+    // Handle TinyMCE editor instances.
+    // TinyMCE forms may not have been initialised at the time that startWatching is called.
+    // Check whether any tinyMCE editor is dirty.
+    if (typeof window.tinyMCE !== 'undefined' && window.tinyMCE.editors) {
+        if (window.tinyMCE.editors.some(editor => editor.isDirty())) {
+            return true;
+        }
+    }
+
+    // No dirty forms detected.
+    return false;
+};
+
+/**
+ * Get the watched form for the specified target.
+ *
+ * @method
+ * @param   {HTMLNode} target
+ * @returns {HTMLFormElement}
+ * @private
+ */
+const getFormForNode = target => watchedForms.find(watchedForm => watchedForm.contains(target));
+
+/**
+ * Whether the specified target is a watched form.
+ *
+ * @method
+ * @param   {HTMLNode} target
+ * @returns {Bool}
+ * @private
+ */
+const isWatchingForm = target => watchedForms.some(watchedForm => watchedForm.contains(target));
+
+/**
+ * Whether the specified target should ignore changes or not.
+ *
+ * @method
+ * @param   {HTMLNode} target
+ * @returns {Bool}
+ * @private
+ */
+const shouldIgnoreChangesForNode = target => !!target.closest('.ignoredirty');
+
+/**
+ * Mark a form as changed.
+ *
+ * @method
+ * @param   {HTMLElement} changedNode An element in the form which was changed
+ */
+export const markFormChangedFromNode = changedNode => {
+    if (changedNode.dataset.formChangeCheckerOverride) {
+        // Changes to this form node disable the form change checker entirely.
+        // This is intended for select fields which cause an immediate redirect.
+        disableAllChecks();
+        return;
+    }
+
+    if (!isWatchingForm(changedNode)) {
+        return;
+    }
+
+    if (shouldIgnoreChangesForNode(changedNode)) {
+        return;
+    }
+
+    // Mark the form as dirty.
+    const formNode = getFormForNode(changedNode);
+    formNode.dataset.formDirty = "true";
+};
+
+/**
+ * Mark a form as submitted.
+ *
+ * @method
+ * @param   {HTMLElement} formNode An element in the form to mark as submitted
+ */
+export const markFormSubmitted = formNode => {
+    formNode = getFormFromChild(formNode);
+
+    if (!formNode) {
+         return;
+    }
+
+    formNode.dataset.formSubmitted = "true";
+};
+
+/**
+ * Mark all forms as submitted.
+ *
+ * This function is only for backwards-compliance with the old YUI module and should not be used in any other situation.
+ * It will be removed in Moodle 4.4.
+ *
+ * @method
+ */
+export const markAllFormsSubmitted = () => {
+    watchedForms.forEach(watchedForm => markFormSubmitted(watchedForm));
+};
+
+/**
+ * Handle the beforeunload event.
+ *
+ * @method
+ * @param   {Event} e
+ * @returns {string|null}
+ * @private
+ */
+const beforeUnloadHandler = e => {
+    // Please note: The use of Promises in this function is forbidden.
+    // This is an event handler and _cannot_ be asynchronous.
+    let warnBeforeUnload = isAnyWatchedFormDirty() && !M.cfg.behatsiterunning;
+    if (warnBeforeUnload) {
+        // According to the specification, to show the confirmation dialog an event handler should call preventDefault()
+        // on the event.
+        e.preventDefault();
+
+        // However note that not all browsers support this method, and some instead require the event handler to
+        // implement one of two legacy methods:
+        // * assigning a string to the event's returnValue property; and
+        // * returning a string from the event handler.
+
+        // Assigning a string to the event's returnValue property.
+        e.returnValue = warningString;
+
+        // Returning a string from the event handler.
+        return e.returnValue;
+    }
+
+    // Attaching an event handler/listener to window or document's beforeunload event prevents browsers from using
+    // in-memory page navigation caches, like Firefox's Back-Forward cache or WebKit's Page Cache.
+    // Remove the handler.
+    window.removeEventListener('beforeunload', beforeUnloadHandler);
+
+    return null;
+};
+
+/**
+ * Start watching for form changes.
+ *
+ * This function is called on module load, and should not normally be called.
+ *
+ * @method
+ * @protected
+ */
+export const startWatching = () => {
+    if (initialised) {
+        return;
+    }
+
+    document.addEventListener('change', e => {
+        if (!isWatchingForm(e.target)) {
+            return;
+        }
+
+        markFormChangedFromNode(e.target);
+    });
+
+    document.addEventListener('click', e => {
+        const ignoredButton = e.target.closest('[data-formchangechecker-ignore-submit]');
+        if (!ignoredButton) {
+            return;
+        }
+
+        const ownerForm = getFormFromChild(e.target);
+        if (ownerForm) {
+            ownerForm.dataset.ignoreSubmission = "true";
+        }
+    });
+
+    document.addEventListener('focusin', e => {
+        if (e.target.matches('input, textarea, select')) {
+            if (e.target.dataset.propertyIsEnumerable('initialValue')) {
+                // The initial value has already been set.
+                return;
+            }
+            e.target.dataset.initialValue = e.target.value;
+        }
+    });
+
+    document.addEventListener('submit', e => {
+        const formNode = getFormFromChild(e.target);
+        if (!formNode) {
+            // Weird, but watch for this anyway.
+            return;
+        }
+
+        if (formNode.dataset.ignoreSubmission) {
+            // This form was submitted by a button which requested that the form checked should not mark it as submitted.
+            formNode.dataset.ignoreSubmission = "false";
+            return;
+        }
+
+        markFormSubmitted(formNode);
+    });
+
+    document.addEventListener(eventTypes.editorContentRestored, e => {
+        if (e.target != document) {
+            resetFormDirtyState(e.target);
+        } else {
+            resetAllFormDirtyStates();
+        }
+    });
+
+    getString('changesmadereallygoaway', 'moodle')
+    .then(changesMadeString => {
+        warningString = changesMadeString;
+        return;
+    })
+    .catch();
+
+    window.addEventListener('beforeunload', beforeUnloadHandler);
+};
+
+/**
+ * Watch the form matching the specified ID for changes.
+ *
+ * @method
+ * @param   {String} formId
+ */
+export const watchFormById = formId => {
+    watchForm(document.getElementById(formId));
+};
+
+/**
+ * Reset the dirty state of the form matching the specified ID..
+ *
+ * @method
+ * @param   {String} formId
+ */
+export const resetFormDirtyStateById = formId => {
+    resetFormDirtyState(document.getElementById(formId));
+};
+
+/**
+ * Mark the form matching the specified ID as dirty.
+ *
+ * @method
+ * @param   {String} formId
+ */
+export const markFormAsDirtyById = formId => {
+    markFormAsDirty(document.getElementById(formId));
+};
+
+// Configure all event listeners.
+startWatching();

lib/form/amd/src/choicedropdown.js

@@ -0,0 +1,158 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Field controller for choicedropdown field.
+ *
+ * @module core_form/choicedropdown
+ * @copyright 2023 Ferran Recio <ferran@moodle.com>
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+import {getDropdownStatus} from 'core/local/dropdown/status';
+import {markFormAsDirty} from 'core_form/changechecker';
+
+const Classes = {
+    notClickable: 'not-clickable',
+    hidden: 'd-none',
+};
+
+/**
+ * Internal form element class.
+ *
+ * @private
+ * @class     FieldController
+ * @copyright  2023 Ferran Recio <ferran@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class FieldController {
+    /**
+     * Class constructor.
+     *
+     * @param {String} elementId Form element id
+     */
+    constructor(elementId) {
+        this.elementId = elementId;
+        this.mainSelect = document.getElementById(this.elementId);
+        this.dropdown = getDropdownStatus(`[data-form-controls="${this.elementId}"]`);
+        this.dropdown.getElement().classList.remove(Classes.hidden);
+    }
+
+    /**
+     * Add form element event listener.
+     */
+    addEventListeners() {
+        this.dropdown.getElement().addEventListener(
+            'change',
+            this.updateSelect.bind(this)
+        );
+        // Click on a dropdown link can trigger a wrong dirty form reload warning.
+        this.dropdown.getElement().addEventListener(
+            'click',
+            (event) => event.preventDefault()
+        );
+        this.mainSelect.addEventListener(
+            'change',
+            this.updateDropdown.bind(this)
+        );
+        // Enabling or disabling the select does not trigger any JS event.
+        const observerCallback = (mutations) => {
+            mutations.forEach((mutation) => {
+                if (mutation.type !== 'attributes' || mutation.attributeName !== 'disabled') {
+                    return;
+                }
+                this.updateDropdown();
+            });
+        };
+        new MutationObserver(observerCallback).observe(
+            this.mainSelect,
+            {attributeFilter: ['disabled']}
+        );
+    }
+
+    /**
+     * Check if the field is disabled.
+     * @returns {Boolean}
+     */
+    isDisabled() {
+        return this.mainSelect?.hasAttribute('disabled');
+    }
+
+    /**
+     * Update selected option preview in form.
+     */
+    async updateDropdown() {
+        this.dropdown.setButtonDisabled(this.isDisabled());
+        if (this.dropdown.getSelectedValue() == this.mainSelect.value) {
+            return;
+        }
+        this.dropdown.setSelectedValue(this.mainSelect.value);
+    }
+
+    /**
+     * Update selected option preview in form.
+     */
+    async updateSelect() {
+        if (this.dropdown.getSelectedValue() == this.mainSelect.value) {
+            return;
+        }
+        this.mainSelect.value = this.dropdown.getSelectedValue();
+        markFormAsDirty(this.mainSelect.closest('form'));
+        // Change the select element via JS does not trigger the standard change event.
+        this.mainSelect.dispatchEvent(new Event('change'));
+    }
+
+    /**
+     * Disable the choice dialog and convert it into a regular select field.
+     */
+    disableInteractiveDialog() {
+        this.mainSelect?.classList.remove(Classes.hidden);
+        const dropdownElement = this.dropdown.getElement();
+        dropdownElement.classList.add(Classes.hidden);
+    }
+
+    /**
+     * Check if the field has a force dialog attribute.
+    //  *
+     * The force dialog is a setting to force the javascript control even in
+     * behat test.
+     *
+     * @returns {Boolean} if the dialog modal should be forced or not
+     */
+    hasForceDialog() {
+        return !!this.mainSelect?.dataset.forceDialog;
+    }
+}
+
+/**
+ * Initialises a choice dialog field.
+ *
+ * @method init
+ * @param {String} elementId Form element id
+ * @listens event:uploadStarted
+ * @listens event:uploadCompleted
+ */
+export const init = (elementId) => {
+    const field = new FieldController(elementId);
+    // This field is just a select wrapper. To optimize tests, we don't want to keep behat
+    // waiting for extra loadings in this case. The set field steps are about testing other
+    // stuff, not to test fancy javascript form fields. However, we keep the possibility of
+    // testing the javascript part using behat when necessary.
+    if (document.body.classList.contains('behat-site') && !field.hasForceDialog()) {
+        field.disableInteractiveDialog();
+        return;
+    }
+    field.addEventListeners();
+};

lib/form/amd/src/collapsesections.js

@@ -0,0 +1,112 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Collapse or expand all form sections on clicking the expand all / collapse al link.
+ *
+ * @module core_form/collapsesections
+ * @copyright 2021 Bas Brands
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @since 4.0
+ */
+
+import $ from 'jquery';
+import Pending from 'core/pending';
+
+const SELECTORS = {
+    FORM: '.mform',
+    FORMHEADER: '.fheader',
+    FORMCONTAINER: 'fieldset > .fcontainer',
+};
+
+const CLASSES = {
+    SHOW: 'show',
+    COLLAPSED: 'collapsed',
+    HIDDEN: 'd-none'
+};
+
+/**
+ * Initialises the form section collapse / expand action.
+ *
+ * @param {string} collapsesections the collapse/expand link id.
+ */
+export const init = collapsesections => {
+    // All jQuery in this code can be replaced when MDL-71979 is integrated (move to Bootstrap 5).
+    const pendingPromise = new Pending('core_form/collapsesections');
+    const collapsemenu = document.querySelector(collapsesections);
+
+    const formParent = collapsemenu.closest(SELECTORS.FORM);
+    const formContainers = formParent.querySelectorAll(SELECTORS.FORMCONTAINER);
+
+    collapsemenu.addEventListener('keydown', e => {
+        if (e.key === 'Enter' || e.key === ' ') {
+            e.preventDefault();
+            collapsemenu.click();
+        }
+    });
+
+    // Override default collapse class if all visible containers are expanded on page load
+    let formcontainercount = 0;
+    let expandedcount = 0;
+    formContainers.forEach(container => {
+        const parentFieldset = container.parentElement;
+        if (!parentFieldset.classList.contains(CLASSES.HIDDEN)) {
+            formcontainercount++;
+        }
+        if (container.classList.contains(CLASSES.SHOW)) {
+            expandedcount++;
+        }
+    });
+
+    if (formcontainercount === expandedcount) {
+        collapsemenu.classList.remove(CLASSES.COLLAPSED);
+        collapsemenu.setAttribute('aria-expanded', true);
+    }
+
+    // When the collapse menu is toggled, update each form container to match.
+    collapsemenu.addEventListener('click', () => {
+        let action = 'hide';
+        if (collapsemenu.classList.contains(CLASSES.COLLAPSED)) {
+            action = 'show';
+        }
+
+        formContainers.forEach(container => $(container).collapse(action));
+    });
+
+    // Ensure collapse menu button adds aria-controls attribute referring to each collapsible element.
+    const collapseElements = formParent.querySelectorAll(SELECTORS.FORMHEADER);
+    const collapseElementIds = [...collapseElements].map((element, index) => {
+        element.id = element.id || `collapseElement-${index}`;
+        return element.id;
+    });
+    collapsemenu.setAttribute('aria-controls', collapseElementIds.join(' '));
+
+    // When any form container is toggled, re-calculate collapse menu state.
+    $(SELECTORS.FORMCONTAINER).on('hidden.bs.collapse', () => {
+        const allCollapsed = [...formContainers].every(container => !container.classList.contains(CLASSES.SHOW));
+        if (allCollapsed) {
+            collapsemenu.classList.add(CLASSES.COLLAPSED);
+            collapsemenu.setAttribute('aria-expanded', false);
+        }
+    });
+    $(SELECTORS.FORMCONTAINER).on('shown.bs.collapse', () => {
+        const allExpanded = [...formContainers].every(container => container.classList.contains(CLASSES.SHOW));
+        if (allExpanded) {
+            collapsemenu.classList.remove(CLASSES.COLLAPSED);
+            collapsemenu.setAttribute('aria-expanded', true);
+        }
+    });
+    pendingPromise.resolve();
+};

lib/form/amd/src/configtext_maxlength.js

@@ -0,0 +1,121 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Validation for configtext_maxlength.
+ *
+ * @module     core_form/configtext-maxlength
+ * @copyright  2021 The Open University
+ */
+import {get_string as getString} from 'core/str';
+import Templates from 'core/templates';
+import Notification from 'core/notification';
+import {prefetchStrings, prefetchTemplates} from 'core/prefetch';
+
+let registered = false;
+
+/**
+ * Initialisation function.
+ */
+export const init = () => {
+    if (registered) {
+        return;
+    }
+    prefetchStrings('core', [
+        'maximumchars',
+    ]);
+
+    prefetchTemplates([
+        'core_form/setting_validation_failure',
+    ]);
+
+    registered = true;
+
+    document.addEventListener('input', e => {
+        const maxLengthField = e.target.closest('[data-validation-max-length]');
+        if (!maxLengthField) {
+            return;
+        }
+
+        if (maxLengthField.value.length > maxLengthField.dataset.validationMaxLength) {
+            // Disable the form for this field.
+            maxLengthField.form.addEventListener('submit', submissionCheck);
+            // Display an error.
+            getString('maximumchars', 'core', maxLengthField.dataset.validationMaxLength)
+                .then(errorMessage => {
+                    return Templates.renderForPromise('core_form/setting_validation_failure', {
+                        fieldid: maxLengthField.id,
+                        message: errorMessage,
+                    });
+                })
+                .then(errorTemplate => {
+                    if (!maxLengthField.dataset.validationFailureId) {
+                        const formWrapper = maxLengthField.closest('.form-text');
+                        Templates.prependNodeContents(formWrapper, errorTemplate.html, errorTemplate.js);
+                        maxLengthField.dataset.validationFailureId = `maxlength_error_${maxLengthField.id}`;
+                        // Disable submit button when the message is displayed.
+                        updateSubmitButton();
+                    }
+                    return;
+                })
+                .then(() => {
+                    maxLengthField.setAttribute('aria-invalid', true);
+                    const errorField = document.getElementById(maxLengthField.dataset.validationFailureId);
+                    if (errorField) {
+                        errorField.setAttribute('aria-describedby', maxLengthField.id);
+                    }
+                    return;
+                })
+                .catch(Notification.exception);
+        } else {
+            // Remove the old message.
+            const validationMessage = document.getElementById(maxLengthField.dataset.validationFailureId);
+            if (validationMessage) {
+                validationMessage.parentElement.remove();
+                delete maxLengthField.dataset.validationFailureId;
+                maxLengthField.removeAttribute('aria-invalid');
+                // Enable submit button when the message was removed.
+                updateSubmitButton();
+            }
+        }
+    });
+};
+
+/**
+ * Handle form submission.
+ *
+ * @param {Event} e The event.
+ */
+const submissionCheck = e => {
+    const maxLengthFields = e.target.querySelectorAll('[data-validation-max-length]');
+    const maxLengthFieldsArray = Array.from(maxLengthFields);
+    maxLengthFieldsArray.some(maxLengthField => {
+        // Focus on the first validation failure.
+        if (maxLengthField.value.length > maxLengthField.dataset.validationMaxLength) {
+            e.preventDefault();
+            maxLengthField.focus();
+            return true;
+        }
+        return false;
+    });
+};
+
+/**
+ * Update submit button.
+ */
+const updateSubmitButton = () => {
+    const shouldDisable = document.querySelector('form#adminsettings .error');
+    document.querySelector('form#adminsettings button[type="submit"]').disabled = !!shouldDisable;
+};

lib/form/amd/src/defaultcustom.js

@@ -0,0 +1,51 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Functionality for the form element defaultcustom
+ *
+ * @module     core_form/defaultcustom
+ * @copyright  2017 Marina Glancy
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @since      3.3
+ */
+define(['jquery'], function($) {
+    var onChangeSelect = function(event) {
+        var element = $(event.target),
+            defaultvalue = JSON.parse(element.attr('data-defaultvalue')),
+            customvalue = JSON.parse(element.attr('data-customvalue')),
+            type = element.attr('data-type'),
+            form = element.closest('form'),
+            elementName = element.attr('name').replace(/\[customize\]$/, '[value]'),
+            newvalue = element.prop('checked') ? customvalue : defaultvalue;
+
+        if (type === 'text') {
+            form.find('[name="' + elementName + '"]').val(newvalue);
+        } else if (type === 'date_selector') {
+            form.find('[name="' + elementName + '[day]"]').val(newvalue.day);
+            form.find('[name="' + elementName + '[month]"]').val(newvalue.month);
+            form.find('[name="' + elementName + '[year]"]').val(newvalue.year);
+        } else if (type === 'date_time_selector') {
+            form.find('[name="' + elementName + '[day]"]').val(newvalue.day);
+            form.find('[name="' + elementName + '[month]"]').val(newvalue.month);
+            form.find('[name="' + elementName + '[year]"]').val(newvalue.year);
+            form.find('[name="' + elementName + '[hour]"]').val(newvalue.hour);
+            form.find('[name="' + elementName + '[minute]"]').val(newvalue.minute);
+        }
+    };
+
+    var selector = 'input[data-defaultcustom=true]';
+    $('body').on('change', selector, onChangeSelect);
+});

lib/form/amd/src/dynamicform.js

@@ -0,0 +1,377 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Display an embedded form, it is only loaded and reloaded inside its container
+ *
+ *
+ * @module     core_form/dynamicform
+ * @copyright  2019 Marina Glancy
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * See also https://docs.moodle.org/dev/Modal_and_AJAX_forms
+ *
+ * @example
+ *    import DynamicForm from 'core_form/dynamicform';
+ *
+ *    const dynamicForm = new DynamicForm(document.querySelector('#mycontainer', 'pluginname\\form\\formname');
+ *    dynamicForm.addEventListener(dynamicForm.events.FORM_SUBMITTED, e => {
+ *        e.preventDefault();
+ *        window.console.log(e.detail);
+ *        dynamicForm.container.innerHTML = 'Thank you, your form is submitted!';
+ *    });
+ *    dynamicForm.load();
+ *
+ */
+
+import * as FormChangeChecker from 'core_form/changechecker';
+import * as FormEvents from 'core_form/events';
+import Ajax from 'core/ajax';
+import Fragment from 'core/fragment';
+import Notification from 'core/notification';
+import Pending from 'core/pending';
+import Templates from 'core/templates';
+import {getStrings} from 'core/str';
+import {serialize} from './util';
+
+/**
+ * @class core_form/dynamicform
+ */
+export default class DynamicForm {
+
+    /**
+     * Various events that can be observed.
+     *
+     * @type {Object}
+     */
+    events = {
+        // Form was successfully submitted - the response is passed to the event listener.
+        // Cancellable (in order to prevent default behavior to clear the container).
+        FORM_SUBMITTED: 'core_form_dynamicform_formsubmitted',
+        // Cancel button was pressed.
+        // Cancellable (in order to prevent default behavior to clear the container).
+        FORM_CANCELLED: 'core_form_dynamicform_formcancelled',
+        // User attempted to submit the form but there was client-side validation error.
+        CLIENT_VALIDATION_ERROR: 'core_form_dynamicform_clientvalidationerror',
+        // User attempted to submit the form but server returned validation error.
+        SERVER_VALIDATION_ERROR: 'core_form_dynamicform_validationerror',
+        // Error occurred while performing request to the server.
+        // Cancellable (by default calls Notification.exception).
+        ERROR: 'core_form_dynamicform_error',
+        // Right after user pressed no-submit button,
+        // listen to this event if you want to add JS validation or processing for no-submit button.
+        // Cancellable.
+        NOSUBMIT_BUTTON_PRESSED: 'core_form_dynamicform_nosubmitbutton',
+        // Right after user pressed submit button,
+        // listen to this event if you want to add additional JS validation or confirmation dialog.
+        // Cancellable.
+        SUBMIT_BUTTON_PRESSED: 'core_form_dynamicform_submitbutton',
+        // Right after user pressed cancel button,
+        // listen to this event if you want to add confirmation dialog.
+        // Cancellable.
+        CANCEL_BUTTON_PRESSED: 'core_form_dynamicform_cancelbutton',
+    };
+
+    /**
+     * Constructor
+     *
+     * Creates an instance
+     *
+     * @param {Element} container - the parent element for the form
+     * @param {string} formClass full name of the php class that extends \core_form\modal , must be in autoloaded location
+     */
+    constructor(container, formClass) {
+        this.formClass = formClass;
+        this.container = container;
+
+        // Ensure strings required for shortforms are always available.
+        getStrings([
+            {key: 'collapseall', component: 'moodle'},
+            {key: 'expandall', component: 'moodle'}
+        ]).catch(Notification.exception);
+
+        // Register delegated events handlers in vanilla JS.
+        this.container.addEventListener('click', e => {
+            if (e.target.matches('form input[type=submit][data-cancel]')) {
+                e.preventDefault();
+                const event = this.trigger(this.events.CANCEL_BUTTON_PRESSED, e.target);
+                if (!event.defaultPrevented) {
+                    this.processCancelButton();
+                }
+            } else if (e.target.matches('form input[type=submit][data-no-submit="1"]')) {
+                e.preventDefault();
+                const event = this.trigger(this.events.NOSUBMIT_BUTTON_PRESSED, e.target);
+                if (!event.defaultPrevented) {
+                    this.processNoSubmitButton(e.target);
+                }
+            }
+        });
+
+        this.container.addEventListener('submit', e => {
+            if (e.target.matches('form')) {
+                e.preventDefault();
+                const event = this.trigger(this.events.SUBMIT_BUTTON_PRESSED);
+                if (!event.defaultPrevented) {
+                    this.submitFormAjax();
+                }
+            }
+        });
+    }
+
+    /**
+     * Loads the form via AJAX and shows it inside a given container
+     *
+     * @param {Object} args
+     * @return {Promise}
+     * @public
+     */
+    load(args = null) {
+        const formData = serialize(args || {});
+        const pendingPromise = new Pending('core_form/dynamicform:load');
+        return this.getBody(formData)
+        .then((resp) => this.updateForm(resp))
+        .then(pendingPromise.resolve);
+    }
+
+    /**
+     * Triggers a custom event
+     *
+     * @private
+     * @param {String} eventName
+     * @param {*} detail
+     * @param {Boolean} cancelable
+     * @return {CustomEvent<unknown>}
+     */
+    trigger(eventName, detail = null, cancelable = true) {
+        const e = new CustomEvent(eventName, {detail, cancelable});
+        this.container.dispatchEvent(e);
+        return e;
+    }
+
+    /**
+     * Add listener for an event
+     *
+     * @param {array} args
+     * @example:
+     *    const dynamicForm = new DynamicForm(...);
+     *    dynamicForm.addEventListener(dynamicForm.events.FORM_SUBMITTED, e => {
+     *        e.preventDefault();
+     *        window.console.log(e.detail);
+     *        dynamicForm.container.innerHTML = 'Thank you, your form is submitted!';
+     *    });
+     */
+    addEventListener(...args) {
+        this.container.addEventListener(...args);
+    }
+
+    /**
+     * Get form body
+     *
+     * @param {String} formDataString form data in format of a query string
+     * @private
+     * @return {Promise}
+     */
+    getBody(formDataString) {
+        return Ajax.call([{
+            methodname: 'core_form_dynamic_form',
+            args: {
+                formdata: formDataString,
+                form: this.formClass,
+            }
+        }])[0]
+        .then(response => {
+            return {html: response.html, js: Fragment.processCollectedJavascript(response.javascript)};
+        });
+    }
+
+    /**
+     * On form submit
+     *
+     * @param {*} response Response received from the form's "process" method
+     */
+    onSubmitSuccess(response) {
+        const event = this.trigger(this.events.FORM_SUBMITTED, response);
+        if (event.defaultPrevented) {
+            return;
+        }
+
+        // Default implementation is to remove the form. Event listener should either remove or reload the form
+        // since its contents is no longer correct. For example, if an element was created as a result of
+        // form submission, the "id" in the form would be still zero. Also the server-side validation
+        // errors from the previous submission may still be present.
+        this.container.innerHTML = '';
+    }
+
+    /**
+     * On exception during form processing
+     *
+     * @private
+     * @param {Object} exception
+     */
+    onSubmitError(exception) {
+        const event = this.trigger(this.events.ERROR, exception);
+        if (event.defaultPrevented) {
+            return;
+        }
+
+        Notification.exception(exception);
+    }
+
+    /**
+     * Click on a "submit" button that is marked in the form as registerNoSubmitButton()
+     *
+     * @method submitButtonPressed
+     * @param {Element} button that was pressed
+     * @fires event:formSubmittedByJavascript
+     */
+    processNoSubmitButton(button) {
+        const pendingPromise = new Pending('core_form/dynamicform:nosubmit');
+        const form = this.getFormNode();
+        const formData = new URLSearchParams([...(new FormData(form)).entries()]);
+        formData.append(button.getAttribute('name'), button.getAttribute('value'));
+
+        FormEvents.notifyFormSubmittedByJavascript(form, true);
+
+        // Add the button name to the form data and submit it.
+        this.disableButtons();
+
+        this.getBody(formData.toString())
+        .then(resp => this.updateForm(resp))
+        .then(pendingPromise.resolve)
+        .catch(exception => this.onSubmitError(exception));
+    }
+
+    /**
+     * Get the form node from the Dialogue.
+     *
+     * @returns {HTMLFormElement}
+     */
+    getFormNode() {
+        return this.container.querySelector('form');
+    }
+
+    /**
+     * Notifies listeners that form dirty state should be reset.
+     *
+     * @fires event:formSubmittedByJavascript
+     */
+    notifyResetFormChanges() {
+        FormEvents.notifyFormSubmittedByJavascript(this.getFormNode(), true);
+        FormChangeChecker.resetFormDirtyState(this.getFormNode());
+    }
+
+    /**
+     * Click on a "cancel" button
+     */
+    processCancelButton() {
+        // Notify listeners that the form is about to be submitted (this will reset atto autosave).
+        this.notifyResetFormChanges();
+
+        const event = this.trigger(this.events.FORM_CANCELLED);
+        if (!event.defaultPrevented) {
+            // By default removes the form from the DOM.
+            this.container.innerHTML = '';
+        }
+    }
+
+    /**
+     * Update form contents
+     *
+     * @param {object} param
+     * @param {string} param.html
+     * @param {string} param.js
+     * @returns {Promise}
+     */
+    updateForm({html, js}) {
+        return Templates.replaceNodeContents(this.container, html, js);
+    }
+
+    /**
+     * Validate form elements
+     * @return {Boolean} Whether client-side validation has passed, false if there are errors
+     * @fires event:formSubmittedByJavascript
+     */
+    validateElements() {
+        // Notify listeners that the form is about to be submitted (this will reset atto autosave).
+        FormEvents.notifyFormSubmittedByJavascript(this.getFormNode());
+
+        // Now the change events have run, see if there are any "invalid" form fields.
+        const invalid = [...this.container.querySelectorAll('[aria-invalid="true"], .error')];
+
+        // If we found invalid fields, focus on the first one and do not submit via ajax.
+        if (invalid.length) {
+            invalid[0].focus();
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * Disable buttons during form submission
+     */
+    disableButtons() {
+        this.container.querySelectorAll('form input[type="submit"]')
+            .forEach(el => el.setAttribute('disabled', true));
+    }
+
+    /**
+     * Enable buttons after form submission (on validation error)
+     */
+    enableButtons() {
+        this.container.querySelectorAll('form input[type="submit"]')
+            .forEach(el => el.removeAttribute('disabled'));
+    }
+
+    /**
+     * Submit the form via AJAX call to the core_form_dynamic_form WS
+     */
+    async submitFormAjax() {
+        // If we found invalid fields, focus on the first one and do not submit via ajax.
+        if (!(await this.validateElements())) {
+            this.trigger(this.events.CLIENT_VALIDATION_ERROR, null, false);
+            return;
+        }
+        this.disableButtons();
+
+        // Convert all the form elements values to a serialised string.
+        const form = this.container.querySelector('form');
+        const formData = new URLSearchParams([...(new FormData(form)).entries()]);
+
+        // Now we can continue...
+        Ajax.call([{
+            methodname: 'core_form_dynamic_form',
+            args: {
+                formdata: formData.toString(),
+                form: this.formClass
+            }
+        }])[0]
+        .then((response) => {
+            if (!response.submitted) {
+                // Form was not submitted, it could be either because validation failed or because no-submit button was pressed.
+                this.updateForm({html: response.html, js: Fragment.processCollectedJavascript(response.javascript)});
+                this.enableButtons();
+                this.trigger(this.events.SERVER_VALIDATION_ERROR, null, false);
+            } else {
+                // Form was submitted properly.
+                const data = JSON.parse(response.data);
+                this.enableButtons();
+                this.notifyResetFormChanges();
+                this.onSubmitSuccess(data);
+            }
+            return null;
+        })
+        .catch(exception => this.onSubmitError(exception));
+    }
+}

lib/form/amd/src/encryptedpassword.js

@@ -0,0 +1,103 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Encrypted password functionality.
+ *
+ * @module core_form/encryptedpassword
+ * @copyright 2019 The Open University
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+/**
+ * Constructor for EncryptedPassword.
+ *
+ * @class core_form/encryptedpassword
+ * @param {String} elementId The element to apply the encrypted password JS to
+ */
+export const EncryptedPassword = function(elementId) {
+    const wrapper = document.querySelector('div[data-encryptedpasswordid="' + elementId + '"]');
+    this.spanOrLink = wrapper.querySelector('span, a');
+    this.input = wrapper.querySelector('input');
+    this.editButtonOrLink = wrapper.querySelector('button[data-editbutton], a');
+    this.cancelButton = wrapper.querySelector('button[data-cancelbutton]');
+
+    // Edit button action.
+    var editHandler = (e) => {
+        e.stopImmediatePropagation();
+        e.preventDefault();
+        this.startEditing(true);
+    };
+    this.editButtonOrLink.addEventListener('click', editHandler);
+
+    // When it's a link, do some magic to make the label work as well.
+    if (this.editButtonOrLink.nodeName === 'A') {
+        wrapper.parentElement.previousElementSibling.querySelector('label').addEventListener('click', editHandler);
+    }
+
+    // Cancel button action.
+    this.cancelButton.addEventListener('click', (e) => {
+        e.stopImmediatePropagation();
+        e.preventDefault();
+        this.cancelEditing();
+    });
+
+    // If the value is not set yet, start editing and remove the cancel option - so that
+    // it saves something in the config table and doesn't keep repeat showing it as a new
+    // admin setting...
+    if (wrapper.dataset.novalue === 'y') {
+        this.startEditing(false);
+        this.cancelButton.style.display = 'none';
+    }
+};
+
+/**
+ * Starts editing.
+ *
+ * @param {Boolean} moveFocus If true, sets focus to the edit box
+ */
+EncryptedPassword.prototype.startEditing = function(moveFocus) {
+    this.input.style.display = 'inline';
+    this.input.disabled = false;
+    this.spanOrLink.style.display = 'none';
+    this.editButtonOrLink.style.display = 'none';
+    this.cancelButton.style.display = 'inline';
+
+    // Move the id around, which changes what happens when you click the label.
+    const id = this.editButtonOrLink.id;
+    this.editButtonOrLink.removeAttribute('id');
+    this.input.id = id;
+
+    if (moveFocus) {
+        this.input.focus();
+    }
+};
+
+/**
+ * Cancels editing.
+ */
+EncryptedPassword.prototype.cancelEditing = function() {
+    this.input.style.display = 'none';
+    this.input.value = '';
+    this.input.disabled = true;
+    this.spanOrLink.style.display = 'inline';
+    this.editButtonOrLink.style.display = 'inline';
+    this.cancelButton.style.display = 'none';
+
+    // Move the id around, which changes what happens when you click the label.
+    const id = this.input.id;
+    this.input.removeAttribute('id');
+    this.editButtonOrLink.id = id;
+};

lib/form/amd/src/events.js

@@ -0,0 +1,367 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Javascript events for the `core_form` subsystem.
+ *
+ * @module core_form/events
+ * @copyright 2021 Huong Nguyen <huongnv13@gmail.com>
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @since 3.10
+ *
+ * @example <caption>Example of listening to a form event.</caption>
+ * import {eventTypes as formEventTypes} from 'core_form/events';
+ *
+ * document.addEventListener(formEventTypes.formSubmittedByJavascript, e => {
+ *     window.console.log(e.target); // The form that was submitted.
+ *     window.console.log(e.detail.skipValidation); // Whether form validation was skipped.
+ * });
+ */
+
+import {getString} from 'core/str';
+import {dispatchEvent} from 'core/event_dispatcher';
+
+let changesMadeString;
+
+/**
+ * Prevent user navigate away when upload progress still running.
+ * @param {Event} e The event
+ */
+const changesMadeCheck = e => {
+    if (e) {
+        e.returnValue = changesMadeString;
+    }
+};
+
+/**
+ * Events for `core_form`.
+ *
+ * @constant
+ * @property {String} formError See {@link event:core_form/error}
+ * @property {String} formFieldValidationFailed See {@link event:core_form/fieldValidationFailed}
+ * @property {String} formSubmittedByJavascript See {@link event:core_form/submittedByJavascript}
+ * @property {String} uploadChanged See {@link event:core_form/uploadChanged}
+ * @property {String} fieldStructureChanged See {@link event:core_form/fieldStructureChanged}
+ */
+export const eventTypes = {
+    /**
+     * An event triggered when a form contains an error
+     *
+     * @event formError
+     * @type {CustomEvent}
+     * @property {HTMLElement} target The form field which errored
+     */
+    formError: 'core_form/error',
+
+    /**
+     * An event triggered when an mform is about to be submitted via javascript.
+     *
+     * @event core_form/submittedByJavascript
+     * @type {CustomEvent}
+     * @property {HTMLElement} target The form that was submitted
+     * @property {object} detail
+     * @property {boolean} detail.skipValidation Whether the form was submitted without validation (i.e. via a Cancel button)
+     * @property {boolean} detail.fallbackHandled Whether the legacy YUI event has been handled
+     */
+    formSubmittedByJavascript: 'core_form/submittedByJavascript',
+
+    /**
+     * An event triggered upon form field validation failure.
+     *
+     * @event core_form/fieldValidationFailed
+     * @type {CustomEvent}
+     * @property {HTMLElement} target The field that failed validation
+     * @property {object} detail
+     * @property {String} detail.message The message displayed upon failure
+     */
+    formFieldValidationFailed: 'core_form/fieldValidationFailed',
+
+    /**
+     * An event triggered when an upload is started
+     *
+     * @event core_form/uploadStarted
+     * @type {CustomEvent}
+     * @property {HTMLElement} target The location where the upload began
+     */
+    uploadStarted: 'core_form/uploadStarted',
+
+    /**
+     * An event triggered when an upload completes
+     *
+     * @event core_form/uploadCompleted
+     * @type {CustomEvent}
+     * @property {HTMLElement} target The location where the upload completed
+     */
+    uploadCompleted: 'core_form/uploadCompleted',
+
+    /**
+     * An event triggered when a file upload field has been changed.
+     *
+     * @event core_form/uploadChanged
+     * @type {CustomEvent}
+     * @property {HTMLElement} target The form field which was changed
+     */
+    uploadChanged: 'core_form/uploadChanged',
+
+    /**
+     * An event triggered when a form field structure has changed.
+     *
+     * @event core_form/fieldStructureChanged
+     * @type {CustomEvent}
+     * @property {HTMLElement} target The form field that has changed
+     */
+    fieldStructureChanged: 'core_form/fieldStructureChanged',
+};
+
+// These are only imported for legacy.
+import jQuery from 'jquery';
+import Y from 'core/yui';
+
+/**
+ * Trigger an event to indicate that a form field contained an error.
+ *
+ * @method notifyFormError
+ * @param {HTMLElement} field The form field causing the error
+ * @returns {CustomEvent}
+ * @fires formError
+ */
+export const notifyFormError = field => dispatchEvent(eventTypes.formError, {}, field);
+
+/**
+ * Trigger an event to indiciate that a form was submitted by Javascript.
+ *
+ * @method
+ * @param {HTMLElement} form The form that was submitted
+ * @param {Boolean} skipValidation Submit the form without validation. E.g. "Cancel".
+ * @param {Boolean} fallbackHandled The legacy YUI event has been handled
+ * @returns {CustomEvent}
+ * @fires formSubmittedByJavascript
+ */
+export const notifyFormSubmittedByJavascript = (form, skipValidation = false, fallbackHandled = false) => {
+    if (skipValidation) {
+        window.skipClientValidation = true;
+    }
+
+    const customEvent = dispatchEvent(
+        eventTypes.formSubmittedByJavascript,
+        {
+            skipValidation,
+            fallbackHandled,
+        },
+        form
+    );
+
+    if (skipValidation) {
+        window.skipClientValidation = false;
+    }
+
+    return customEvent;
+};
+
+/**
+ * Trigger an event to indicate that a form field contained an error.
+ *
+ * @method notifyFieldValidationFailure
+ * @param {HTMLElement} field The field which failed validation
+ * @param {String} message The message displayed
+ * @returns {CustomEvent}
+ * @fires formFieldValidationFailed
+ */
+export const notifyFieldValidationFailure = (field, message) => dispatchEvent(
+    eventTypes.formFieldValidationFailed,
+    {
+        message,
+    },
+    field,
+    {
+        cancelable: true
+    }
+);
+
+/**
+ * Trigger an event to indicate that an upload was started.
+ *
+ * @method
+ * @param {String} elementId The element which was uploaded to
+ * @returns {CustomEvent}
+ * @fires uploadStarted
+ */
+export const notifyUploadStarted = async elementId => {
+    // Add an additional check for changes made.
+    changesMadeString = await getString('changesmadereallygoaway', 'moodle');
+    window.addEventListener('beforeunload', changesMadeCheck);
+
+    return dispatchEvent(
+        eventTypes.uploadStarted,
+        {},
+        document.getElementById(elementId),
+        {
+            bubbles: true,
+            cancellable: false,
+        }
+    );
+};
+
+/**
+ * Trigger an event to indicate that an upload was completed.
+ *
+ * @method
+ * @param {String} elementId The element which was uploaded to
+ * @returns {CustomEvent}
+ * @fires uploadCompleted
+ */
+export const notifyUploadCompleted = elementId => {
+    // Remove the additional check for changes made.
+    window.removeEventListener('beforeunload', changesMadeCheck);
+
+    return dispatchEvent(
+        eventTypes.uploadCompleted,
+        {},
+        document.getElementById(elementId),
+        {
+            bubbles: true,
+            cancellable: false,
+        }
+    );
+};
+
+/**
+ * Trigger upload start event.
+ *
+ * @method
+ * @param {String} elementId
+ * @returns {CustomEvent}
+ * @fires uploadStarted
+ * @deprecated Since Moodle 4.0 See {@link module:core_form/events.notifyUploadStarted notifyUploadStarted}
+ */
+export const triggerUploadStarted = notifyUploadStarted;
+
+/**
+ * Trigger upload complete event.
+ *
+ * @method
+ * @param {String} elementId
+ * @returns {CustomEvent}
+ * @fires uploadCompleted
+ * @deprecated Since Moodle 4.0 See {@link module:core_form/events.notifyUploadCompleted notifyUploadCompleted}
+ */
+export const triggerUploadCompleted = notifyUploadCompleted;
+
+/**
+ * List of the events.
+ *
+ * @deprecated since Moodle 4.0. See {@link module:core_form/events.eventTypes eventTypes} instead.
+ **/
+export const types = {
+    uploadStarted: 'core_form/uploadStarted',
+    uploadCompleted: 'core_form/uploadCompleted',
+};
+
+let legacyEventsRegistered = false;
+if (!legacyEventsRegistered) {
+    // The following event triggers are legacy and will be removed in the future.
+    // The following approach provides a backwards-compatability layer for the new events.
+    // Code should be updated to make use of native events.
+    Y.use('event', 'moodle-core-event', () => {
+
+        // Watch for the new native formError event, and trigger the legacy YUI event.
+        document.addEventListener(eventTypes.formError, e => {
+            const element = Y.one(e.target);
+            const formElement = Y.one(e.target.closest('form'));
+
+            Y.Global.fire(
+                M.core.globalEvents.FORM_ERROR,
+                {
+                    formid: formElement.generateID(),
+                    elementid: element.generateID(),
+                }
+            );
+        });
+
+        // Watch for the new native formSubmittedByJavascript event, and trigger the legacy YUI event.
+        document.addEventListener(eventTypes.formSubmittedByJavascript, e => {
+            if (e.detail.fallbackHandled) {
+                // This event was originally generated by a YUI event.
+                // Do not generate another as this will recurse.
+                return;
+            }
+
+            if (e.skipValidation) {
+                window.skipClientValidation = true;
+            }
+
+            // Trigger the legacy YUI event.
+            const form = Y.one(e.target);
+            form.fire(
+                M.core.event.FORM_SUBMIT_AJAX,
+                {
+                    currentTarget: form,
+                    fallbackHandled: true,
+                }
+            );
+
+            if (e.skipValidation) {
+                window.skipClientValidation = false;
+            }
+        });
+    });
+
+    // Watch for the new native formFieldValidationFailed event, and trigger the legacy jQuery event.
+    document.addEventListener(eventTypes.formFieldValidationFailed, e => {
+        // Note: The "core_form-field-validation" event is hard-coded in core/event.
+        // This is not included to prevent cyclic module dependencies.
+        const legacyEvent = jQuery.Event("core_form-field-validation");
+
+        jQuery(e.target).trigger(legacyEvent, e.detail.message);
+    });
+
+    legacyEventsRegistered = true;
+}
+
+/**
+ * Trigger an event to notify the file upload field has been changed.
+ *
+ * @method
+ * @param {string} elementId The element which was changed
+ * @returns {CustomEvent}
+ * @fires uploadChanged
+ */
+export const notifyUploadChanged = elementId => dispatchEvent(
+    eventTypes.uploadChanged,
+    {},
+    document.getElementById(elementId),
+    {
+        bubbles: true,
+        cancellable: false,
+    }
+);
+
+/**
+ * Trigger an event to notify the field structure has changed.
+ *
+ * @method
+ * @param {string} elementId The element which was changed
+ * @returns {CustomEvent}
+ * @fires fieldStructureChanged
+ */
+export const notifyFieldStructureChanged = elementId => dispatchEvent(
+    eventTypes.fieldStructureChanged,
+    {},
+    document.getElementById(elementId),
+    {
+        bubbles: true,
+        cancellable: false,
+    }
+);

lib/form/amd/src/filetypes.js

@@ -0,0 +1,304 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * This module allows to enhance the form elements MoodleQuickForm_filetypes
+ *
+ * @module     core_form/filetypes
+ * @copyright  2017 David Mudrak <david@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @since      3.3
+ */
+define(['jquery', 'core/log', 'core/modal_events', 'core/modal_save_cancel', 'core/ajax',
+        'core/templates', 'core/tree'],
+    function($, Log, ModalEvents, ModalSaveCancel, Ajax, Templates, Tree) {
+
+    "use strict";
+
+    /**
+     * Constructor of the FileTypes instances.
+     *
+     * @constructor
+     * @param {String} elementId The id of the form element to enhance
+     * @param {String} elementLabel The label of the form element used as the modal selector title
+     * @param {String} onlyTypes Limit the list of offered types to this
+     * @param {Bool} allowAll Allow presence of the "All file types" item
+     */
+    var FileTypes = function(elementId, elementLabel, onlyTypes, allowAll) {
+
+        this.elementId = elementId;
+        this.elementLabel = elementLabel;
+        this.onlyTypes = onlyTypes;
+        this.allowAll = allowAll;
+
+        this.inputField = $('#' + elementId);
+        this.wrapperBrowserTrigger = $('[data-filetypesbrowser="' + elementId + '"]');
+        this.wrapperDescriptions = $('[data-filetypesdescriptions="' + elementId + '"]');
+
+        if (!this.wrapperBrowserTrigger.length) {
+            // This is a valid case. Most probably the element is frozen and
+            // the filetypes browser should not be available.
+            return;
+        }
+
+        if (!this.inputField.length || !this.wrapperDescriptions.length) {
+            Log.error('core_form/filetypes: Unexpected DOM structure, unable to enhance filetypes field ' + elementId);
+            return;
+        }
+
+        this.prepareBrowserTrigger()
+            .then(function() {
+                return this.prepareBrowserModal();
+            }.bind(this))
+
+            .then(function() {
+                return this.prepareBrowserTree();
+            }.bind(this));
+    };
+
+    /**
+     * Create and set the browser trigger widget (this.browserTrigger).
+     *
+     * @method prepareBrowserTrigger
+     * @returns {Promise}
+     */
+    FileTypes.prototype.prepareBrowserTrigger = function() {
+        return Templates.render('core_form/filetypes-trigger', {})
+            .then(function(html) {
+                this.wrapperBrowserTrigger.html(html);
+                this.browserTrigger = this.wrapperBrowserTrigger.find('[data-filetypeswidget="browsertrigger"]');
+            }.bind(this));
+    };
+
+    /**
+     * Create and set the modal for displaying the browser (this.browserModal).
+     *
+     * @method prepareBrowserModal
+     * @returns {Promise}
+     */
+    FileTypes.prototype.prepareBrowserModal = function() {
+        return ModalSaveCancel.create({
+            title: this.elementLabel,
+        })
+        .then(function(modal) {
+            this.browserModal = modal;
+            return modal;
+        }.bind(this))
+        .then(function() {
+            // Because we have custom conditional modal trigger, we need to
+            // handle the focus after closing ourselves, too.
+            this.browserModal.getRoot().on(ModalEvents.hidden, function() {
+                this.browserTrigger.focus();
+            }.bind(this));
+
+            this.browserModal.getRoot().on(ModalEvents.save, function() {
+                this.saveBrowserModal();
+            }.bind(this));
+        }.bind(this));
+
+    };
+
+    /**
+     * Create and set the tree in the browser modal's body.
+     *
+     * @method prepareBrowserTree
+     * @returns {Promise}
+     */
+    FileTypes.prototype.prepareBrowserTree = function() {
+
+        this.browserTrigger.on('click', function(e) {
+            e.preventDefault();
+
+            // We want to display the browser modal only when the associated input
+            // field is not frozen (disabled).
+            if (this.inputField.is('[disabled]')) {
+                return;
+            }
+
+            var bodyContent = this.loadBrowserModalBody();
+
+            bodyContent.then(function() {
+
+                // Turn the list of groups and extensions into the tree.
+                this.browserTree = new Tree(this.browserModal.getBody());
+
+                // Override the behaviour of the Enter and Space keys to toggle our checkbox,
+                // rather than toggle the tree node expansion status.
+                this.browserTree.handleKeyDown = function(item, e) {
+                    if (e.keyCode == this.browserTree.keys.enter || e.keyCode == this.browserTree.keys.space) {
+                        e.preventDefault();
+                        e.stopPropagation();
+                        this.toggleCheckbox(item.attr('data-filetypesbrowserkey'));
+                    } else {
+                        Tree.prototype.handleKeyDown.call(this.browserTree, item, e);
+                    }
+                }.bind(this);
+
+                if (this.allowAll) {
+                    // Hide all other items if "All file types" is enabled.
+                    this.hideOrShowItemsDependingOnAllowAll(this.browserModal.getRoot()
+                        .find('input[type="checkbox"][data-filetypesbrowserkey="*"]').first());
+                    // And do the same whenever we click that checkbox.
+                    this.browserModal.getRoot().on('change', 'input[type="checkbox"][data-filetypesbrowserkey="*"]', function(e) {
+                        this.hideOrShowItemsDependingOnAllowAll($(e.currentTarget));
+                    }.bind(this));
+                }
+
+                // Synchronize checked status if the file extension is present in multiple groups.
+                this.browserModal.getRoot().on('change', 'input[type="checkbox"][data-filetypesbrowserkey]', function(e) {
+                    var checkbox = $(e.currentTarget);
+                    var key = checkbox.attr('data-filetypesbrowserkey');
+                    this.browserModal.getRoot().find('input[type="checkbox"][data-filetypesbrowserkey="' + key + '"]')
+                        .prop('checked', checkbox.prop('checked'));
+                }.bind(this));
+
+            }.bind(this))
+
+            .then(function() {
+                this.browserModal.show();
+            }.bind(this));
+
+            this.browserModal.setBody(bodyContent);
+
+        }.bind(this));
+
+        // Return a resolved promise.
+        return $.when();
+    };
+
+    /**
+     * Load the browser modal body contents.
+     *
+     * @returns {Promise}
+     */
+    FileTypes.prototype.loadBrowserModalBody = function() {
+
+        var args = {
+            onlytypes: this.onlyTypes.join(),
+            allowall: this.allowAll,
+            current: this.inputField.val()
+        };
+
+        return Ajax.call([{
+            methodname: 'core_form_get_filetypes_browser_data',
+            args: args
+
+        }])[0].then(function(browserData) {
+            return Templates.render('core_form/filetypes-browser', {
+                elementid: this.elementId,
+                groups: browserData.groups
+            });
+        }.bind(this));
+    };
+
+    /**
+     * Change the checked status of the given file type (group or extension).
+     *
+     * @method toggleCheckbox
+     * @param {String} key
+     */
+    FileTypes.prototype.toggleCheckbox = function(key) {
+
+        var checkbox = this.browserModal.getRoot().find('input[type="checkbox"][data-filetypesbrowserkey="' + key + '"]').first();
+
+        checkbox.prop('checked', !checkbox.prop('checked'));
+    };
+
+    /**
+     * Update the associated input field with selected file types.
+     *
+     * @method saveBrowserModal
+     */
+    FileTypes.prototype.saveBrowserModal = function() {
+
+        // Check the "All file types" first.
+        if (this.allowAll) {
+            var allcheckbox = this.browserModal.getRoot().find('input[type="checkbox"][data-filetypesbrowserkey="*"]');
+            if (allcheckbox.length && allcheckbox.prop('checked')) {
+                this.inputField.val('*');
+                this.updateDescriptions(['*']);
+                return;
+            }
+        }
+
+        // Iterate over all checked boxes and populate the list.
+        var newvalue = [];
+
+        this.browserModal.getRoot().find('input[type="checkbox"]').each(/** @this represents the checkbox */ function() {
+            var checkbox = $(this);
+            var key = checkbox.attr('data-filetypesbrowserkey');
+
+            if (checkbox.prop('checked')) {
+                newvalue.push(key);
+            }
+        });
+
+        // Remove duplicates (e.g. file types present in multiple groups).
+        newvalue = newvalue.filter(function(x, i, a) {
+            return a.indexOf(x) == i;
+        });
+
+        this.inputField.val(newvalue.join(' '));
+        this.updateDescriptions(newvalue);
+    };
+
+    /**
+     * Describe the selected filetypes in the form when saving the browser.
+     *
+     * @param {Array} keys List of keys to describe
+     * @returns {Promise}
+     */
+    FileTypes.prototype.updateDescriptions = function(keys) {
+
+        var descriptions = [];
+
+        keys.forEach(function(key) {
+            descriptions.push({
+                description: this.browserModal.getRoot().find('[data-filetypesname="' + key + '"]').first().text().trim(),
+                extensions: this.browserModal.getRoot().find('[data-filetypesextensions="' + key + '"]').first().text().trim()
+            });
+        }.bind(this));
+
+        var templatedata = {
+            hasdescriptions: (descriptions.length > 0),
+            descriptions: descriptions
+        };
+
+        return Templates.render('core_form/filetypes-descriptions', templatedata)
+            .then(function(html) {
+                this.wrapperDescriptions.html(html);
+            }.bind(this));
+    };
+
+    /**
+     * If "All file types" is checked, all other browser items are made hidden, and vice versa.
+     *
+     * @param {jQuery} allcheckbox The "All file types" checkbox.
+     */
+    FileTypes.prototype.hideOrShowItemsDependingOnAllowAll = function(allcheckbox) {
+        var others = this.browserModal.getRoot().find('[role="treeitem"][data-filetypesbrowserkey!="*"]');
+        if (allcheckbox.prop('checked')) {
+            others.hide();
+        } else {
+            others.show();
+        }
+    };
+
+    return {
+        init: function(elementId, elementLabel, onlyTypes, allowAll) {
+            new FileTypes(elementId, elementLabel, onlyTypes, allowAll);
+        }
+    };
+});

lib/form/amd/src/modalform.js

@@ -0,0 +1,432 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Display a form in a modal dialogue
+ *
+ * Example:
+ *    import ModalForm from 'core_form/modalform';
+ *
+ *    const modalForm = new ModalForm({
+ *        formClass: 'pluginname\\form\\formname',
+ *        modalConfig: {title: 'Here comes the title'},
+ *        args: {categoryid: 123},
+ *        returnFocus: e.target,
+ *    });
+ *    modalForm.addEventListener(modalForm.events.FORM_SUBMITTED, (c) => window.console.log(c.detail));
+ *    modalForm.show();
+ *
+ * See also https://docs.moodle.org/dev/Modal_and_AJAX_forms
+ *
+ * @module     core_form/modalform
+ * @copyright  2018 Mitxel Moriana <mitxel@tresipunt.>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+import Ajax from 'core/ajax';
+import * as FormChangeChecker from 'core_form/changechecker';
+import * as FormEvents from 'core_form/events';
+import Fragment from 'core/fragment';
+import ModalEvents from 'core/modal_events';
+import Notification from 'core/notification';
+import Pending from 'core/pending';
+import {serialize} from './util';
+
+export default class ModalForm {
+
+    /**
+     * Various events that can be observed.
+     *
+     * @type {Object}
+     */
+    events = {
+        // Form was successfully submitted - the response is passed to the event listener.
+        // Cancellable (but it's hardly ever needed to cancel this event).
+        FORM_SUBMITTED: 'core_form_modalform_formsubmitted',
+        // Cancel button was pressed.
+        // Cancellable (but it's hardly ever needed to cancel this event).
+        FORM_CANCELLED: 'core_form_modalform_formcancelled',
+        // User attempted to submit the form but there was client-side validation error.
+        CLIENT_VALIDATION_ERROR: 'core_form_modalform_clientvalidationerror',
+        // User attempted to submit the form but server returned validation error.
+        SERVER_VALIDATION_ERROR: 'core_form_modalform_validationerror',
+        // Error occurred while performing request to the server.
+        // Cancellable (by default calls Notification.exception).
+        ERROR: 'core_form_modalform_error',
+        // Right after user pressed no-submit button,
+        // listen to this event if you want to add JS validation or processing for no-submit button.
+        // Cancellable.
+        NOSUBMIT_BUTTON_PRESSED: 'core_form_modalform_nosubmitbutton',
+        // Right after user pressed submit button,
+        // listen to this event if you want to add additional JS validation or confirmation dialog.
+        // Cancellable.
+        SUBMIT_BUTTON_PRESSED: 'core_form_modalform_submitbutton',
+        // Right after user pressed cancel button,
+        // listen to this event if you want to add confirmation dialog.
+        // Cancellable.
+        CANCEL_BUTTON_PRESSED: 'core_form_modalform_cancelbutton',
+        // Modal was loaded and this.modal is available (but the form content may not be loaded yet).
+        LOADED: 'core_form_modalform_loaded',
+    };
+
+    /**
+     * Constructor
+     *
+     * Shows the required form inside a modal dialogue
+     *
+     * @param {Object} config parameters for the form and modal dialogue:
+     * @paramy {String} config.formClass PHP class name that handles the form (should extend \core_form\modal )
+     * @paramy {String} config.moduleName module name to use if different to core/modal_save_cancel (optional)
+     * @paramy {Object} config.modalConfig modal config - title, header, footer, etc.
+     *              Default: {removeOnClose: true, large: true}
+     * @paramy {Object} config.args Arguments for the initial form rendering (for example, id of the edited entity)
+     * @paramy {String} config.saveButtonText the text to display on the Modal "Save" button (optional)
+     * @paramy {String} config.saveButtonClasses additional CSS classes for the Modal "Save" button
+     * @paramy {HTMLElement} config.returnFocus element to return focus to after the dialogue is closed
+     */
+    constructor(config) {
+        this.modal = null;
+        this.config = config;
+        this.config.modalConfig = {
+            removeOnClose: true,
+            large: true,
+            ...(this.config.modalConfig || {}),
+        };
+        this.config.args = this.config.args || {};
+        this.futureListeners = [];
+    }
+
+    /**
+     * Loads the modal module and creates an instance
+     *
+     * @returns {Promise}
+     */
+    getModalModule() {
+        if (!this.config.moduleName && this.config.modalConfig.type && this.config.modalConfig.type !== 'SAVE_CANCEL') {
+            // Legacy loader for plugins that were not updated with Moodle 4.3 changes.
+            window.console.warn(
+                'Passing config.modalConfig.type to ModalForm has been deprecated since Moodle 4.3. ' +
+                'Please pass config.modalName instead with the full module name.',
+            );
+            return import('core/modal_factory')
+                .then((ModalFactory) => ModalFactory.create(this.config.modalConfig));
+        } else {
+            // New loader for Moodle 4.3 and above.
+            const moduleName = this.config.moduleName ?? 'core/modal_save_cancel';
+            return import(moduleName)
+                .then((module) => module.create(this.config.modalConfig));
+        }
+    }
+
+    /**
+     * Initialise the modal and shows it
+     *
+     * @return {Promise}
+     */
+    show() {
+        const pendingPromise = new Pending('core_form/modalform:init');
+
+        return this.getModalModule()
+        .then((modal) => {
+            this.modal = modal;
+
+            // Retrieve the form and set the modal body. We can not set the body in the modalConfig,
+            // we need to make sure that the modal already exists when we render the form. Some form elements
+            // such as date_selector inspect the existing elements on the page to find the highest z-index.
+            const formParams = serialize(this.config.args || {});
+            const bodyContent = this.getBody(formParams);
+            this.modal.setBodyContent(bodyContent);
+            bodyContent.catch(Notification.exception);
+
+            // After successfull submit, when we press "Cancel" or close the dialogue by clicking on X in the top right corner.
+            this.modal.getRoot().on(ModalEvents.hidden, () => {
+                this.notifyResetFormChanges();
+                this.modal.destroy();
+                // Focus on the element that actually launched the modal.
+                if (this.config.returnFocus) {
+                    this.config.returnFocus.focus();
+                }
+            });
+
+            // Add the class to the modal dialogue.
+            this.modal.getModal().addClass('modal-form-dialogue');
+
+            // We catch the press on submit buttons in the forms.
+            this.modal.getRoot().on('click', 'form input[type=submit][data-no-submit]',
+                (e) => {
+                    e.preventDefault();
+                    const event = this.trigger(this.events.NOSUBMIT_BUTTON_PRESSED, e.target);
+                    if (!event.defaultPrevented) {
+                        this.processNoSubmitButton(e.target);
+                    }
+                });
+
+            // We catch the form submit event and use it to submit the form with ajax.
+            this.modal.getRoot().on('submit', 'form', (e) => {
+                e.preventDefault();
+                const event = this.trigger(this.events.SUBMIT_BUTTON_PRESSED);
+                if (!event.defaultPrevented) {
+                    this.submitFormAjax();
+                }
+            });
+
+            // Change the text for the save button.
+            if (typeof this.config.saveButtonText !== 'undefined' &&
+                typeof this.modal.setSaveButtonText !== 'undefined') {
+                this.modal.setSaveButtonText(this.config.saveButtonText);
+            }
+            // Set classes for the save button.
+            if (typeof this.config.saveButtonClasses !== 'undefined') {
+                this.setSaveButtonClasses(this.config.saveButtonClasses);
+            }
+            // When Save button is pressed - submit the form.
+            this.modal.getRoot().on(ModalEvents.save, (e) => {
+                e.preventDefault();
+                this.modal.getRoot().find('form').submit();
+            });
+
+            // When Cancel button is pressed - allow to intercept.
+            this.modal.getRoot().on(ModalEvents.cancel, (e) => {
+                const event = this.trigger(this.events.CANCEL_BUTTON_PRESSED);
+                if (event.defaultPrevented) {
+                    e.preventDefault();
+                }
+            });
+            this.futureListeners.forEach(args => this.modal.getRoot()[0].addEventListener(...args));
+            this.futureListeners = [];
+            this.trigger(this.events.LOADED, null, false);
+            return this.modal.show();
+        })
+        .then(pendingPromise.resolve);
+    }
+
+    /**
+     * Triggers a custom event
+     *
+     * @private
+     * @param {String} eventName
+     * @param {*} detail
+     * @param {Boolean} cancelable
+     * @return {CustomEvent<unknown>}
+     */
+    trigger(eventName, detail = null, cancelable = true) {
+        const e = new CustomEvent(eventName, {detail, cancelable});
+        this.modal.getRoot()[0].dispatchEvent(e);
+        return e;
+    }
+
+    /**
+     * Add listener for an event
+     *
+     * @param {array} args
+     * @example:
+     *    const modalForm = new ModalForm(...);
+     *    dynamicForm.addEventListener(modalForm.events.FORM_SUBMITTED, e => {
+     *        window.console.log(e.detail);
+     *    });
+     */
+    addEventListener(...args) {
+        if (!this.modal) {
+            this.futureListeners.push(args);
+        } else {
+            this.modal.getRoot()[0].addEventListener(...args);
+        }
+    }
+
+    /**
+     * Get form contents (to be used in ModalForm.setBodyContent())
+     *
+     * @param {String} formDataString form data in format of a query string
+     * @method getBody
+     * @private
+     * @return {Promise}
+     */
+    getBody(formDataString) {
+        const params = {
+            formdata: formDataString,
+            form: this.config.formClass
+        };
+        const pendingPromise = new Pending('core_form/modalform:form_body');
+        return Ajax.call([{
+            methodname: 'core_form_dynamic_form',
+            args: params
+        }])[0]
+        .then(response => {
+            pendingPromise.resolve();
+            return {html: response.html, js: Fragment.processCollectedJavascript(response.javascript)};
+        })
+        .catch(exception => this.onSubmitError(exception));
+    }
+
+    /**
+     * On exception during form processing or initial rendering. Caller may override.
+     *
+     * @param {Object} exception
+     */
+    onSubmitError(exception) {
+        const event = this.trigger(this.events.ERROR, exception);
+        if (event.defaultPrevented) {
+            return;
+        }
+
+        Notification.exception(exception);
+    }
+
+    /**
+     * Notifies listeners that form dirty state should be reset.
+     *
+     * @fires event:formSubmittedByJavascript
+     */
+    notifyResetFormChanges() {
+        const form = this.getFormNode();
+        if (!form) {
+            return;
+        }
+
+        FormEvents.notifyFormSubmittedByJavascript(form, true);
+
+        FormChangeChecker.resetFormDirtyState(form);
+    }
+
+    /**
+     * Get the form node from the Dialogue.
+     *
+     * @returns {HTMLFormElement}
+     */
+    getFormNode() {
+        return this.modal.getRoot().find('form')[0];
+    }
+
+    /**
+     * Click on a "submit" button that is marked in the form as registerNoSubmitButton()
+     *
+     * @param {Element} button button that was pressed
+     * @fires event:formSubmittedByJavascript
+     */
+    processNoSubmitButton(button) {
+        const form = this.getFormNode();
+        if (!form) {
+            return;
+        }
+
+        FormEvents.notifyFormSubmittedByJavascript(form, true);
+
+        // Add the button name to the form data and submit it.
+        let formData = this.modal.getRoot().find('form').serialize();
+        formData = formData + '&' + encodeURIComponent(button.getAttribute('name')) + '=' +
+            encodeURIComponent(button.getAttribute('value'));
+
+        const bodyContent = this.getBody(formData);
+        this.modal.setBodyContent(bodyContent);
+        bodyContent.catch(Notification.exception);
+    }
+
+    /**
+     * Validate form elements
+     * @return {Boolean} Whether client-side validation has passed, false if there are errors
+     * @fires event:formSubmittedByJavascript
+     */
+    validateElements() {
+        FormEvents.notifyFormSubmittedByJavascript(this.getFormNode());
+
+        // Now the change events have run, see if there are any "invalid" form fields.
+        /** @var {jQuery} list of elements with errors */
+        const invalid = this.modal.getRoot().find('[aria-invalid="true"], .error');
+
+        // If we found invalid fields, focus on the first one and do not submit via ajax.
+        if (invalid.length) {
+            invalid.first().focus();
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * Disable buttons during form submission
+     */
+    disableButtons() {
+        this.modal.getFooter().find('[data-action]').attr('disabled', true);
+    }
+
+    /**
+     * Enable buttons after form submission (on validation error)
+     */
+    enableButtons() {
+        this.modal.getFooter().find('[data-action]').removeAttr('disabled');
+    }
+
+    /**
+     * Submit the form via AJAX call to the core_form_dynamic_form WS
+     */
+    async submitFormAjax() {
+        // If we found invalid fields, focus on the first one and do not submit via ajax.
+        if (!this.validateElements()) {
+            this.trigger(this.events.CLIENT_VALIDATION_ERROR, null, false);
+            return;
+        }
+        this.disableButtons();
+
+        // Convert all the form elements values to a serialised string.
+        const form = this.modal.getRoot().find('form');
+        const formData = form.serialize();
+
+        // Now we can continue...
+        Ajax.call([{
+            methodname: 'core_form_dynamic_form',
+            args: {
+                formdata: formData,
+                form: this.config.formClass
+            }
+        }])[0]
+        .then((response) => {
+            if (!response.submitted) {
+                // Form was not submitted because validation failed.
+                const promise = new Promise(
+                    resolve => resolve({html: response.html, js: Fragment.processCollectedJavascript(response.javascript)}));
+                this.modal.setBodyContent(promise);
+                this.enableButtons();
+                this.trigger(this.events.SERVER_VALIDATION_ERROR);
+            } else {
+                // Form was submitted properly. Hide the modal and execute callback.
+                const data = JSON.parse(response.data);
+                FormChangeChecker.markFormSubmitted(form[0]);
+                const event = this.trigger(this.events.FORM_SUBMITTED, data);
+                if (!event.defaultPrevented) {
+                    this.modal.hide();
+                }
+            }
+            return null;
+        })
+        .catch(exception => {
+            this.enableButtons();
+            this.onSubmitError(exception);
+        });
+    }
+
+    /**
+     * Set the classes for the 'save' button.
+     *
+     * @method setSaveButtonClasses
+     * @param {(String)} value The 'save' button classes.
+     */
+    setSaveButtonClasses(value) {
+        const button = this.modal.getFooter().find("[data-action='save']");
+        if (!button) {
+            throw new Error("Unable to find the 'save' button");
+        }
+        button.removeClass().addClass(value);
+    }
+}

lib/form/amd/src/passwordunmask.js

@@ -0,0 +1,299 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Password Unmask functionality.
+ *
+ * @module     core_form/passwordunmask
+ * @copyright  2016 Andrew Nicols <andrew@nicols.co.uk>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @since      3.2
+ */
+define(['jquery', 'core/templates'], function($, Template) {
+
+    /**
+     * Constructor for PasswordUnmask.
+     *
+     * @class core_form/passwordunmask
+     * @param   {String}    elementid   The element to apply the PasswordUnmask to
+     */
+    var PasswordUnmask = function(elementid) {
+        // Setup variables.
+        this.wrapperSelector = '[data-passwordunmask="wrapper"][data-passwordunmaskid="' + elementid + '"]';
+        this.wrapper = $(this.wrapperSelector);
+        this.editorSpace = this.wrapper.find('[data-passwordunmask="editor"]');
+        this.editLink = this.wrapper.find('a[data-passwordunmask="edit"]');
+        this.editInstructions = this.wrapper.find('[data-passwordunmask="instructions"]');
+        this.displayValue = this.wrapper.find('[data-passwordunmask="displayvalue"]');
+        this.inputFieldLabel = $('label[for="' + elementid + '"]');
+
+        this.inputField = this.editorSpace.find(document.getElementById(elementid));
+        // Hide the field.
+        this.inputField.addClass('d-none');
+        this.inputField.removeClass('hiddenifjs');
+
+        if (!this.editInstructions.attr('id')) {
+            this.editInstructions.attr('id', elementid + '_instructions');
+        }
+        this.editInstructions.hide();
+
+        this.setDisplayValue();
+
+        // Add the listeners.
+        this.addListeners();
+    };
+
+    /**
+     * Add the event listeners required for PasswordUnmask.
+     *
+     * @method  addListeners
+     * @return  {PasswordUnmask}
+     * @chainable
+     */
+    PasswordUnmask.prototype.addListeners = function() {
+        this.wrapper.on('click keypress', '[data-passwordunmask="edit"]', $.proxy(function(e) {
+            if (e.type === 'keypress' && e.keyCode !== 13) {
+                return;
+            }
+            e.stopImmediatePropagation();
+            e.preventDefault();
+
+            if (this.isEditing()) {
+                // Only focus on the edit link if the event was not a click, and the new target is not an input field.
+                if (e.type !== 'click' && !$(e.relatedTarget).is(':input')) {
+                    this.turnEditingOff(true);
+                } else {
+                    this.turnEditingOff(false);
+                }
+            } else {
+                this.turnEditingOn();
+            }
+        }, this));
+
+        this.wrapper.on('click keypress', '[data-passwordunmask="unmask"]', $.proxy(function(e) {
+            if (e.type === 'keypress' && e.keyCode !== 13) {
+                return;
+            }
+            e.stopImmediatePropagation();
+            e.preventDefault();
+
+            // Toggle the data attribute.
+            this.wrapper.data('unmasked', !this.wrapper.data('unmasked'));
+
+            this.setDisplayValue();
+        }, this));
+
+        this.wrapper.on('keydown', 'input', $.proxy(function(e) {
+            if (e.type === 'keydown' && e.keyCode !== 13) {
+                return;
+            }
+
+            e.stopImmediatePropagation();
+            e.preventDefault();
+
+            this.turnEditingOff(true);
+        }, this));
+
+        this.inputFieldLabel.on('click', $.proxy(function(e) {
+            e.preventDefault();
+
+            this.turnEditingOn();
+        }, this));
+
+        return this;
+    };
+
+    /**
+     * Check whether focus was lost from the PasswordUnmask and turn editing off if required.
+     *
+     * @method  checkFocusOut
+     * @param   {EventFacade}   e       The EventFacade generating the suspsected Focus Out
+     */
+    PasswordUnmask.prototype.checkFocusOut = function(e) {
+        if (!this.isEditing()) {
+            // Ignore - not editing.
+            return;
+        }
+
+        window.setTimeout($.proxy(function() {
+            // Firefox does not have the focusout event. Instead jQuery falls back to the 'blur' event.
+            // The blur event does not have a relatedTarget, so instead we use a timeout and the new activeElement.
+            var relatedTarget = e.relatedTarget || document.activeElement;
+            if (this.wrapper.has($(relatedTarget)).length) {
+                // Ignore, some part of the element is still active.
+                return;
+            }
+
+            // Only focus on the edit link if the new related target is not an input field or anchor.
+            this.turnEditingOff(!$(relatedTarget).is(':input,a'));
+        }, this), 100);
+    };
+
+    /**
+     * Whether the password is currently visible (unmasked).
+     *
+     * @method  passwordVisible
+     * @return  {Boolean}            True if the password is unmasked
+     */
+    PasswordUnmask.prototype.passwordVisible = function() {
+        return !!this.wrapper.data('unmasked');
+    };
+
+    /**
+     * Whether the user is currently editing the field.
+     *
+     * @method  isEditing
+     * @return  {Boolean}            True if edit mode is enabled
+     */
+    PasswordUnmask.prototype.isEditing = function() {
+        return this.inputField.hasClass('d-inline-block');
+    };
+
+    /**
+     * Enable the editing functionality.
+     *
+     * @method  turnEditingOn
+     * @return  {PasswordUnmask}
+     * @chainable
+     */
+    PasswordUnmask.prototype.turnEditingOn = function() {
+        var value = this.getDisplayValue();
+        if (this.passwordVisible()) {
+            this.inputField.attr('type', 'text');
+        } else {
+            this.inputField.attr('type', 'password');
+        }
+        this.inputField.val(value);
+        this.inputField.attr('size', this.inputField.attr('data-size'));
+        // Show the field.
+        this.inputField.addClass('d-inline-block');
+
+        if (this.editInstructions.length) {
+            this.inputField.attr('aria-describedby', this.editInstructions.attr('id'));
+            this.editInstructions.show();
+        }
+
+        this.wrapper.attr('data-passwordunmask-visible', 1);
+
+        this.editLink.hide();
+        this.inputField
+            .focus()
+            .select();
+
+        // Note, this cannot be added as a delegated listener on init because Firefox does not support the FocusOut
+        // event (https://bugzilla.mozilla.org/show_bug.cgi?id=687787) and the blur event does not identify the
+        // relatedTarget.
+        // The act of focusing the this.inputField means that in Firefox the focusout will be triggered on blur of the edit
+        // link anchor.
+        $('body').on('focusout', this.wrapperSelector, $.proxy(this.checkFocusOut, this));
+
+        return this;
+    };
+
+    /**
+     * Disable the editing functionality, optionally focusing on the edit link.
+     *
+     * @method  turnEditingOff
+     * @param   {Boolean}       focusOnEditLink     Whether to focus on the edit link after disabling the editor
+     * @return  {PasswordUnmask}
+     * @chainable
+     */
+    PasswordUnmask.prototype.turnEditingOff = function(focusOnEditLink) {
+        $('body').off('focusout', this.wrapperSelector, this.checkFocusOut);
+        var value = this.getDisplayValue();
+        this.inputField
+            // Ensure that the aria-describedby is removed.
+            .attr('aria-describedby', null);
+        this.inputField.val(value);
+        // Hide the field again.
+        this.inputField.removeClass('d-inline-block');
+
+        this.editInstructions.hide();
+
+        // Remove the visible attr.
+        this.wrapper.removeAttr('data-passwordunmask-visible');
+
+        // Remove the size attr.
+        this.inputField.removeAttr('size');
+
+        this.editLink.show();
+        this.setDisplayValue();
+
+        if (focusOnEditLink) {
+            this.editLink.focus();
+        }
+
+        return this;
+    };
+
+    /**
+     * Get the currently value.
+     *
+     * @method  getDisplayValue
+     * @return  {String}
+     */
+    PasswordUnmask.prototype.getDisplayValue = function() {
+        return this.inputField.val();
+    };
+
+    /**
+     * Set the currently value in the display, taking into account the current settings.
+     *
+     * @method  setDisplayValue
+     * @return  {PasswordUnmask}
+     * @chainable
+     */
+    PasswordUnmask.prototype.setDisplayValue = function() {
+        var value = this.getDisplayValue();
+        if (this.isEditing()) {
+            if (this.wrapper.data('unmasked')) {
+                this.inputField.attr('type', 'text');
+            } else {
+                this.inputField.attr('type', 'password');
+            }
+            this.inputField.val(value);
+        }
+
+        // Update the display value.
+        // Note: This must always be updated.
+        // The unmask value can be changed whilst editing and the editing can then be disabled.
+        if (value && this.wrapper.data('unmasked')) {
+            // There is a value, and we will show it.
+            this.displayValue.text(value);
+        } else {
+            if (!value) {
+                value = "";
+            }
+            // There is a value, but it will be disguised.
+            // We use the passwordunmask-fill to allow modification of the fill and to ensure that the display does not
+            // change as the page loads the JS.
+            Template.render('core_form/element-passwordunmask-fill', {
+                element: {
+                    frozen:     this.inputField.is('[readonly]'),
+                    value:      value,
+                    valuechars: value.split(''),
+                },
+            }).done($.proxy(function(html, js) {
+                this.displayValue.html(html);
+
+                Template.runTemplateJS(js);
+            }, this));
+        }
+
+        return this;
+    };
+
+    return PasswordUnmask;
+});

lib/form/amd/src/showadvanced.js

@@ -0,0 +1,227 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * A class to help show and hide advanced form content.
+ *
+ * @module     core_form/showadvanced
+ * @copyright  2016 Damyon Wiese <damyon@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+define(['jquery', 'core/log', 'core/str', 'core/notification'], function($, Log, Strings, Notification) {
+
+    var SELECTORS = {
+            FIELDSETCONTAINSADVANCED: 'fieldset.containsadvancedelements',
+            DIVFITEMADVANCED: 'div.fitem.advanced',
+            DIVADVANCEDSECTION: 'div#form-advanced-div',
+            DIVFCONTAINER: 'div.fcontainer',
+            MORELESSLINK: 'fieldset.containsadvancedelements .moreless-toggler'
+        },
+        CSS = {
+            SHOW: 'show',
+            MORELESSACTIONS: 'moreless-actions',
+            MORELESSTOGGLER: 'moreless-toggler',
+            SHOWLESS: 'moreless-less'
+        },
+        WRAPPERS = {
+            FITEM: '<div class="fitem"></div>',
+            FELEMENT: '<div class="felement"></div>',
+            ADVANCEDDIV: '<div id="form-advanced-div"></div>'
+        },
+        IDPREFIX = 'showadvancedid-';
+
+    /** @property {Integer} uniqIdSeed Auto incrementing number used to generate ids. */
+    var uniqIdSeed = 0;
+
+    /**
+     * ShowAdvanced behaviour class.
+     *
+     * @class core_form/showadvanced
+     * @param {String} id The id of the form.
+     */
+    var ShowAdvanced = function(id) {
+        this.id = id;
+
+        var form = $(document.getElementById(id));
+        this.enhanceForm(form);
+    };
+
+    /** @property {String} id The form id to enhance. */
+    ShowAdvanced.prototype.id = '';
+
+    /**
+     * @method enhanceForm
+     * @param {JQuery} form JQuery selector representing the form
+     * @return {ShowAdvanced}
+     */
+    ShowAdvanced.prototype.enhanceForm = function(form) {
+        var fieldsets = form.find(SELECTORS.FIELDSETCONTAINSADVANCED);
+
+        // Enhance each fieldset in the form matching the selector.
+        fieldsets.each(function(index, item) {
+            this.enhanceFieldset($(item));
+        }.bind(this));
+
+        // Attach some event listeners.
+        // Subscribe more/less links to click event.
+        form.on('click', SELECTORS.MORELESSLINK, this.switchState);
+
+        // Subscribe to key events but filter for space or enter.
+        form.on('keydown', SELECTORS.MORELESSLINK, function(e) {
+            // Enter or space.
+            if (e.which == 13 || e.which == 32) {
+                return this.switchState(e);
+            }
+            return true;
+        }.bind(this));
+        return this;
+    };
+
+
+    /**
+     * Generates a uniq id for the dom element it's called on unless the element already has an id.
+     * The id is set on the dom node before being returned.
+     *
+     * @method generateId
+     * @param {JQuery} node JQuery selector representing a single DOM Node.
+     * @return {String}
+     */
+    ShowAdvanced.prototype.generateId = function(node) {
+        var id = node.prop('id');
+        if (typeof id === 'undefined') {
+            id = IDPREFIX + (uniqIdSeed++);
+            node.prop('id', id);
+        }
+        return id;
+    };
+
+    /**
+     * @method enhanceFieldset
+     * @param {JQuery} fieldset JQuery selector representing a fieldset
+     * @return {ShowAdvanced}
+     */
+    ShowAdvanced.prototype.enhanceFieldset = function(fieldset) {
+        var statuselement = $('input[name=mform_showmore_' + fieldset.prop('id') + ']');
+        if (!statuselement.length) {
+            Log.debug("M.form.showadvanced::processFieldset was called on an fieldset without a status field: '" +
+                fieldset.prop('id') + "'");
+            return this;
+        }
+
+        // Fetch some strings.
+        Strings.get_strings([{
+            key: 'showmore',
+            component: 'core_form'
+        }, {
+            key: 'showless',
+            component: 'core_form'
+        }]).then(function(results) {
+            var showmore = results[0],
+                showless = results[1];
+
+            // Generate more/less links.
+            var morelesslink = $('<a href="#"></a>');
+            morelesslink.addClass(CSS.MORELESSTOGGLER);
+            if (statuselement.val() === '0') {
+                morelesslink.html(showmore);
+                morelesslink.attr('aria-expanded', 'false');
+            } else {
+                morelesslink.html(showless);
+                morelesslink.attr('aria-expanded', 'true');
+                morelesslink.addClass(CSS.SHOWLESS);
+                fieldset.find(SELECTORS.DIVFITEMADVANCED).addClass(CSS.SHOW);
+            }
+            // Build a list of advanced fieldsets.
+            var idlist = [];
+            fieldset.find(SELECTORS.DIVFITEMADVANCED).each(function(index, node) {
+                idlist[idlist.length] = this.generateId($(node));
+            }.bind(this));
+
+            // Set aria attributes.
+            morelesslink.attr('role', 'button');
+            morelesslink.attr('aria-controls', 'form-advanced-div');
+
+            var formadvancedsection = $(WRAPPERS.ADVANCEDDIV);
+            fieldset.find(SELECTORS.DIVFITEMADVANCED).wrapAll(formadvancedsection);
+            // Add elements to the DOM.
+            var fitem = $(WRAPPERS.FITEM);
+            fitem.addClass(CSS.MORELESSACTIONS);
+            var felement = $(WRAPPERS.FELEMENT);
+            felement.append(morelesslink);
+            fitem.append(felement);
+
+            fieldset.find(SELECTORS.DIVADVANCEDSECTION).before(fitem);
+            return true;
+        }.bind(this)).fail(Notification.exception);
+
+        return this;
+    };
+
+    /**
+     * @method switchState
+     * @param {Event} e Event that triggered this action.
+     * @return {Boolean}
+     */
+    ShowAdvanced.prototype.switchState = function(e) {
+        e.preventDefault();
+
+        // Fetch some strings.
+        Strings.get_strings([{
+            key: 'showmore',
+            component: 'core_form'
+        }, {
+            key: 'showless',
+            component: 'core_form'
+        }]).then(function(results) {
+            var showmore = results[0],
+                showless = results[1],
+                fieldset = $(e.target).closest(SELECTORS.FIELDSETCONTAINSADVANCED);
+
+            // Toggle collapsed class.
+            fieldset.find(SELECTORS.DIVFITEMADVANCED).toggleClass(CSS.SHOW);
+
+            // Get corresponding hidden variable.
+            var statuselement = $('input[name=mform_showmore_' + fieldset.prop('id') + ']');
+
+            // Invert it and change the link text.
+            if (statuselement.val() === '0') {
+                statuselement.val(1);
+                $(e.target).addClass(CSS.SHOWLESS);
+                $(e.target).html(showless);
+                $(e.target).attr('aria-expanded', 'true');
+            } else {
+                statuselement.val(0);
+                $(e.target).removeClass(CSS.SHOWLESS);
+                $(e.target).html(showmore);
+                $(e.target).attr('aria-expanded', 'false');
+            }
+            return true;
+        }).fail(Notification.exception);
+
+        return this;
+    };
+
+    return {
+        /**
+         * Initialise this module.
+         * @method init
+         * @param {String} formid
+         * @return {ShowAdvanced}
+         */
+        init: function(formid) {
+            return new ShowAdvanced(formid);
+        }
+    };
+});

lib/form/amd/src/submit.js

@@ -0,0 +1,165 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Submit button JavaScript. All submit buttons will be automatically disabled once the form is
+ * submitted, unless that submission results in an error/cancelling the submit.
+ *
+ * @module core_form/submit
+ * @copyright 2019 The Open University
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @since 3.8
+ */
+
+import {eventTypes} from 'core_form/events';
+
+/** @property {number} ID for setInterval used when polling for download cookie */
+let cookieListener = 0;
+
+/** @property {Array} Array of buttons that need re-enabling if we get a download cookie */
+const cookieListeningButtons = [];
+
+/** @property {number} Number of files uploading. */
+let currentUploadCount = 0;
+
+/** @property {Array} Array of buttons that need re-enabling if we get a upload process. */
+const uploadListeningButtons = [];
+
+/** @property {Boolean} Is upload listeners registered? */
+let uploadListenersRegistered = false;
+
+/**
+ * Listens in case a download cookie is provided.
+ *
+ * This function is used to detect file downloads. If there is a file download then we get a
+ * beforeunload event, but the page is never unloaded and when the file download completes we
+ * should re-enable the buttons. We detect this by watching for a specific cookie.
+ *
+ * PHP function \core_form\util::form_download_complete() can be used to send this cookie.
+ *
+ * @param {HTMLElement} button Button to re-enable
+ */
+const listenForDownloadCookie = (button) => {
+    cookieListeningButtons.push(button);
+    if (!cookieListener) {
+        cookieListener = setInterval(() => {
+            // Look for cookie.
+            const parts = document.cookie.split(getCookieName() + '=');
+            if (parts.length == 2) {
+                // We found the cookie, so the file is ready. Expire the cookie and cancel polling.
+                clearDownloadCookie();
+                clearInterval(cookieListener);
+                cookieListener = 0;
+
+                // Re-enable all the buttons.
+                cookieListeningButtons.forEach((button) => {
+                    button.disabled = false;
+                });
+            }
+        }, 500);
+    }
+};
+
+/**
+ * Gets a unique name for the download cookie.
+ *
+ * @returns {string} Cookie name
+ */
+const getCookieName = () => {
+    return 'moodledownload_' + M.cfg.sesskey;
+};
+
+/**
+ * Clears the download cookie if there is one.
+ */
+const clearDownloadCookie = () => {
+    document.cookie = encodeURIComponent(getCookieName()) + '=deleted; expires=' + new Date(0).toUTCString();
+};
+
+/**
+ * Enable submit buttons when all files are uploaded.
+ */
+const checkUploadCount = () => {
+    if (currentUploadCount) {
+        uploadListeningButtons.forEach(button => {
+            button.disabled = true;
+        });
+    } else {
+        uploadListeningButtons.forEach(button => {
+            button.disabled = false;
+        });
+    }
+};
+
+/**
+ * Initialises submit buttons.
+ *
+ * @param {String} elementId Form button element
+ * @listens event:uploadStarted
+ * @listens event:uploadCompleted
+ */
+export const init = (elementId) => {
+    const button = document.getElementById(elementId);
+    if (button === null) {
+        // Exit early if invalid element id passed.
+        return;
+    }
+
+    // If buttons are disabled by default, we do not enable them when file upload completed event is fired.
+    if (!button.disabled) {
+        uploadListeningButtons.push(button);
+    }
+
+    if (!uploadListenersRegistered) {
+        // Add event listener for file upload start.
+        document.addEventListener(eventTypes.uploadStarted, () => {
+            currentUploadCount++;
+            checkUploadCount();
+        });
+
+        // Add event listener for file upload complete.
+        document.addEventListener(eventTypes.uploadCompleted, () => {
+            currentUploadCount--;
+            checkUploadCount();
+        });
+        uploadListenersRegistered = true;
+    }
+
+    // If the form has double submit protection disabled, do nothing.
+    if (button.form.dataset.doubleSubmitProtection === 'off') {
+        return;
+    }
+    button.form.addEventListener('submit', function(event) {
+        // Only disable it if the browser is really going to another page as a result of the
+        // submit.
+        const disableAction = function() {
+            // If the submit was cancelled, or the button is already disabled, don't do anything.
+            if (event.defaultPrevented || button.disabled) {
+                return;
+            }
+
+            button.disabled = true;
+            clearDownloadCookie();
+            listenForDownloadCookie(button);
+        };
+        window.addEventListener('beforeunload', disableAction);
+        // If there is no beforeunload event as a result of this form submit, then the form
+        // submit must have been cancelled, so don't disable the button if the page is
+        // unloaded later.
+        setTimeout(function() {
+            window.removeEventListener('beforeunload', disableAction);
+        }, 1);
+    }, false);
+};

lib/form/amd/src/util.js

@@ -0,0 +1,30 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Serialize form values into a string.
+ *
+ * This must be used instead of URLSearchParams, which does not correctly encode nested values such as arrays.
+ *
+ * @param {Object} data The form values to serialize
+ * @param {string} prefix The prefix to use for key names
+ * @returns {string}
+ */
+export const serialize = (data, prefix = '') => [
+    ...Object.entries(data).map(([index, value]) => {
+        const key = prefix ? `${prefix}[${index}]` : index;
+        return (value !== null && typeof value === "object") ? serialize(value, key) : `${key}=${encodeURIComponent(value)}`;
+    })
+].join("&");

lib/form/autocomplete.php

@@ -0,0 +1,257 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * autocomplete type form element
+ *
+ * Contains HTML class for a autocomplete type element
+ *
+ * @package   core_form
+ * @copyright 2015 Damyon Wiese <damyon@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+
+require_once($CFG->libdir . '/form/select.php');
+
+/**
+ * Autocomplete as you type form element
+ *
+ * HTML class for a autocomplete type element
+ *
+ * @package   core_form
+ * @copyright 2015 Damyon Wiese <damyon@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_autocomplete extends MoodleQuickForm_select {
+
+    /** @var boolean $tags Should we allow typing new entries to the field? */
+    protected $tags = false;
+    /** @var string $ajax Name of an AMD module to send/process ajax requests. */
+    protected $ajax = '';
+    /** @var string $placeholder Placeholder text for an empty list. */
+    protected $placeholder = '';
+    /** @var bool $casesensitive Whether the search has to be case-sensitive. */
+    protected $casesensitive = false;
+    /** @var bool $showsuggestions Show suggestions by default - but this can be turned off. */
+    protected $showsuggestions = true;
+    /** @var string $noselectionstring String that is shown when there are no selections. */
+    protected $noselectionstring = '';
+    /** @var callable|null Function to call (with existing value) to render it to HTML */
+    protected $valuehtmlcallback = null;
+
+    /**
+     * constructor
+     *
+     * @param string $elementName Select name attribute
+     * @param mixed $elementLabel Label(s) for the select
+     * @param mixed $options Data to be used to populate options
+     * @param mixed $attributes Either a typical HTML attribute string or an associative array. Special options
+     *                          "tags", "placeholder", "ajax", "multiple", "casesensitive" are supported.
+     */
+    public function __construct($elementName=null, $elementLabel=null, $options=null, $attributes=null) {
+        // Even if the constructor gets called twice we do not really want 2x options (crazy forms!).
+        $this->_options = array();
+        if ($attributes === null) {
+            $attributes = array();
+        }
+        if (isset($attributes['tags'])) {
+            $this->tags = $attributes['tags'];
+            unset($attributes['tags']);
+        }
+        if (isset($attributes['showsuggestions'])) {
+            $this->showsuggestions = $attributes['showsuggestions'];
+            unset($attributes['showsuggestions']);
+        }
+        $this->placeholder = get_string('search');
+        if (isset($attributes['placeholder'])) {
+            $this->placeholder = $attributes['placeholder'];
+            unset($attributes['placeholder']);
+        }
+        $this->noselectionstring = get_string('noselection', 'form');
+        if (isset($attributes['noselectionstring'])) {
+            $this->noselectionstring = $attributes['noselectionstring'];
+            unset($attributes['noselectionstring']);
+        }
+
+        if (isset($attributes['ajax'])) {
+            $this->ajax = $attributes['ajax'];
+            unset($attributes['ajax']);
+        }
+        if (isset($attributes['casesensitive'])) {
+            $this->casesensitive = $attributes['casesensitive'] ? true : false;
+            unset($attributes['casesensitive']);
+        }
+        if (isset($attributes['valuehtmlcallback'])) {
+            $this->valuehtmlcallback = $attributes['valuehtmlcallback'];
+            unset($attributes['valuehtmlcallback']);
+        }
+        parent::__construct($elementName, $elementLabel, $options, $attributes);
+
+        $this->_type = 'autocomplete';
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_autocomplete($elementName=null, $elementLabel=null, $options=null, $attributes=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $options, $attributes);
+    }
+
+    /**
+     * Returns HTML for select form element.
+     *
+     * @return string
+     */
+    function toHtml(){
+        global $PAGE;
+
+        // Enhance the select with javascript.
+        $this->_generateId();
+        $id = $this->getAttribute('id');
+
+        if (!$this->isFrozen()) {
+            $PAGE->requires->js_call_amd('core/form-autocomplete', 'enhance', $params = array('#' . $id, $this->tags, $this->ajax,
+                $this->placeholder, $this->casesensitive, $this->showsuggestions, $this->noselectionstring));
+        }
+
+        $html = parent::toHTML();
+
+        // Hacky bodge to add in the HTML code to the option tag. There is a nicer
+        // version of this code in the new template version (see export_for_template).
+        if ($this->valuehtmlcallback) {
+            $html = preg_replace_callback('~value="([^"]+)"~', function($matches) {
+                $value = html_entity_decode($matches[1], ENT_COMPAT);
+                $htmlvalue = call_user_func($this->valuehtmlcallback, $value);
+                if ($htmlvalue !== false) {
+                    return $matches[0] . ' data-html="' . s($htmlvalue) . '"';
+                } else {
+                    return $matches[0];
+                }
+            }, $html);
+        }
+
+        return $html;
+    }
+
+    /**
+     * Search the current list of options to see if there are any options with this value.
+     * @param  string $value to search
+     * @return boolean
+     */
+    function optionExists($value) {
+        foreach ($this->_options as $option) {
+            if (isset($option['attr']['value']) && ($option['attr']['value'] == $value)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Set the value of this element. If values can be added or are unknown, we will
+     * make sure they exist in the options array.
+     * @param  mixed string|array $value The value to set.
+     * @return boolean
+     */
+    function setValue($value) {
+        $values = (array) $value;
+        foreach ($values as $onevalue) {
+            if (($this->tags || $this->ajax) &&
+                    (!$this->optionExists($onevalue)) &&
+                    ($onevalue !== '_qf__force_multiselect_submission')) {
+                $this->addOption($onevalue, $onevalue);
+            }
+        }
+        return parent::setValue($value);
+    }
+
+    /**
+     * Returns a 'safe' element's value
+     *
+     * @param  array   array of submitted values to search
+     * @param  bool    whether to return the value as associative array
+     * @access public
+     * @return mixed
+     */
+    function exportValue(&$submitValues, $assoc = false) {
+        if ($this->ajax || $this->tags) {
+            // When this was an ajax request, we do not know the allowed list of values.
+            $value = $this->_findValue($submitValues);
+            if (null === $value) {
+                $value = $this->getValue();
+            }
+            // Quickforms inserts a duplicate element in the form with
+            // this value so that a value is always submitted for this form element.
+            // Normally this is cleaned as a side effect of it not being a valid option,
+            // but in this case we need to detect and skip it manually.
+            if ($value === '_qf__force_multiselect_submission' || $value === null) {
+                $value = $this->getMultiple() ? [] : '';
+            }
+            return $this->_prepareValue($value, $assoc);
+        } else {
+            return parent::exportValue($submitValues, $assoc);
+        }
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return bool
+     */
+    function onQuickFormEvent($event, $arg, &$caller)
+    {
+        switch ($event) {
+            case 'createElement':
+                $caller->setType($arg[0], PARAM_TAGLIST);
+                break;
+        }
+        return parent::onQuickFormEvent($event, $arg, $caller);
+    }
+
+    public function export_for_template(renderer_base $output) {
+        $this->_generateId();
+        $context = parent::export_for_template($output);
+        $context['tags'] = !empty($this->tags);
+        $context['ajax'] = $this->ajax;
+        $context['placeholder'] = $this->placeholder;
+        $context['casesensitive'] = !empty($this->casesensitive);
+        $context['showsuggestions'] = !empty($this->showsuggestions);
+        $context['noselectionstring'] = $this->noselectionstring;
+        if ($this->valuehtmlcallback) {
+            foreach ($context['options'] as &$option) {
+                $value = $option['value'];
+                $html = call_user_func($this->valuehtmlcallback, $value);
+                if ($html !== false) {
+                    $option['html'] = $html;
+                    if ($this->isFrozen()) {
+                        $option['text'] = $html;
+                    }
+                }
+            }
+        }
+
+        return $context;
+    }
+}

lib/form/button.php

@@ -0,0 +1,131 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Button form element
+ *
+ * Contains HTML class for a button type element
+ *
+ * @package   core_form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once("HTML/QuickForm/button.php");
+require_once(__DIR__ . '/../outputcomponents.php');
+require_once('templatable_form_element.php');
+
+/**
+ * HTML class for a button type element
+ *
+ * Overloaded {@link HTML_QuickForm_button} to add help button
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_button extends HTML_QuickForm_button implements templatable
+{
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+
+    /** @var string html for help button, if empty then no help */
+    var $_helpbutton='';
+
+    /** @var bool if true label will be hidden. */
+    protected $_hiddenLabel = false;
+
+    /**
+     * Any class apart from 'btn' would be overridden with this content.
+     *
+     * By default, buttons will utilize the btn-secondary class. However, there are cases where we
+     * require a button with different stylings (e.g. btn-primary). In these cases, $customclassoverride will override
+     * the defaults mentioned previously and utilize the provided class(es).
+     *
+     * @var null|string $customclassoverride Custom class override for the input element
+     */
+    protected $customclassoverride;
+
+    /**
+     * constructor
+     *
+     * @param string $elementName (optional) name for the button
+     * @param string $value (optional) value for the button
+     * @param mixed $attributes (optional) Either a typical HTML attribute string
+     *              or an associative array
+     * @param array $options Options to further customise the button. Currently accepted options are:
+     *                  customclassoverride String The CSS class to use for the button instead of the standard
+     *                                             btn-primary and btn-secondary classes.
+     */
+    public function __construct($elementName=null, $value=null, $attributes=null, $options = []) {
+        parent::__construct($elementName, $value, $attributes);
+
+        $this->customclassoverride = $options['customclassoverride'] ?? null;
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_button($elementName=null, $value=null, $attributes=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $value, $attributes);
+    }
+
+    /**
+     * get html for help button
+     *
+     * @return string html for help button
+     */
+    function getHelpButton(){
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Slightly different container template when frozen.
+     *
+     * @return string
+     */
+    function getElementTemplateType(){
+        if ($this->_flagFrozen){
+            return 'nodisplay';
+        } else {
+            return 'default';
+        }
+    }
+
+    /**
+     * Sets label to be hidden
+     *
+     * @param bool $hiddenLabel sets if label should be hidden
+     */
+    public function setHiddenLabel($hiddenLabel) {
+        $this->_hiddenLabel = $hiddenLabel;
+    }
+
+    public function export_for_template(renderer_base $output) {
+        $context = $this->export_for_template_base($output);
+
+        if ($this->customclassoverride) {
+            $context['customclassoverride'] = $this->customclassoverride;
+        }
+        return $context;
+    }
+}

lib/form/cancel.php

@@ -0,0 +1,114 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Button form element
+ *
+ * Contains HTML class for a button type element
+ *
+ * @package   core_form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+if (!defined('MOODLE_INTERNAL')) {
+    die('Direct access to this script is forbidden.');    //  It must be included from a Moodle page
+}
+
+global $CFG;
+require_once($CFG->libdir.'/form/submit.php');
+
+/**
+ * HTML class for a submit cancel type element
+ *
+ * Overloaded {@link MoodleQuickForm_submit} with default behavior modified to cancel a form.
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_cancel extends MoodleQuickForm_submit
+{
+    /**
+     * constructor
+     *
+     * @param string $elementName (optional) name of the checkbox
+     * @param string $value (optional) value for the button
+     * @param mixed $attributes (optional) Either a typical HTML attribute string
+     *              or an associative array
+     */
+    public function __construct($elementName=null, $value=null, $attributes=null)
+    {
+        if ($elementName==null){
+            $elementName='cancel';
+        }
+        if ($value==null){
+            $value=get_string('cancel');
+        }
+        parent::__construct($elementName, $value, $attributes);
+        $this->updateAttributes(array('data-skip-validation' => 1, 'data-cancel' => 1,
+            'onclick' => 'skipClientValidation = true; return true;'));
+
+        // Add the class btn-cancel.
+        $class = $this->getAttribute('class');
+        if (empty($class)) {
+            $class = '';
+        }
+        $this->updateAttributes(array('class' => $class . ' btn-cancel'));
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_cancel($elementName=null, $value=null, $attributes=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $value, $attributes);
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return bool
+     */
+    function onQuickFormEvent($event, $arg, &$caller)
+    {
+        switch ($event) {
+            case 'createElement':
+                parent::onQuickFormEvent($event, $arg, $caller);
+                $caller->_registerCancelButton($this->getName());
+                return true;
+                break;
+        }
+        return parent::onQuickFormEvent($event, $arg, $caller);
+    }
+
+    /**
+     * Returns the value of field without HTML tags
+     *
+     * @return string
+     */
+    function getFrozenHtml(){
+        return HTML_QuickForm_submit::getFrozenHtml();
+    }
+
+}

lib/form/checkbox.php

@@ -0,0 +1,153 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * checkbox form element
+ *
+ * Contains HTML class for a checkbox type element
+ *
+ * @package   core_form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once('HTML/QuickForm/checkbox.php');
+require_once('templatable_form_element.php');
+
+/**
+ * HTML class for a checkbox type element
+ *
+ * Overloaded {@link HTML_QuickForm_checkbox} to add help button. Also, fixes bug in quickforms
+ * checkbox, which lets previous set value override submitted value if checkbox is not checked
+ * and no value is submitted
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_checkbox extends HTML_QuickForm_checkbox implements templatable {
+
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+
+    /** @var string html for help button, if empty then no help */
+    var $_helpbutton='';
+
+    /**
+     * Constructor
+     *
+     * @param string $elementName (optional) name of the checkbox
+     * @param string $elementLabel (optional) checkbox label
+     * @param string $text (optional) Text to put after the checkbox
+     * @param mixed $attributes (optional) Either a typical HTML attribute string
+     *              or an associative array
+     */
+    public function __construct($elementName=null, $elementLabel=null, $text='', $attributes=null) {
+        parent::__construct($elementName, $elementLabel, $text, $attributes);
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_checkbox($elementName=null, $elementLabel=null, $text='', $attributes=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $text, $attributes);
+    }
+
+    /**
+     * get html for help button
+     *
+     * @return string html for help button
+     */
+    function getHelpButton(){
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return bool
+     */
+    function onQuickFormEvent($event, $arg, &$caller)
+    {
+        //fixes bug in quickforms which lets previous set value override submitted value if checkbox is not checked
+        // and no value is submitted
+        switch ($event) {
+            case 'updateValue':
+                // constant values override both default and submitted ones
+                // default values are overriden by submitted
+                $value = $this->_findValue($caller->_constantValues);
+                if (null === $value) {
+                    // if no boxes were checked, then there is no value in the array
+                    // yet we don't want to display default value in this case
+                    if ($caller->isSubmitted() && !$caller->is_new_repeat($this->getName())) {
+                        $value = $this->_findValue($caller->_submitValues);
+                    } else {
+
+                        $value = $this->_findValue($caller->_defaultValues);
+                    }
+                }
+                //fix here. setChecked should not be conditional
+                $this->setChecked($value);
+                break;
+            default:
+                parent::onQuickFormEvent($event, $arg, $caller);
+        }
+        return true;
+    }
+
+    /**
+     * Returns HTML for checbox form element.
+     *
+     * @return string
+     */
+    function toHtml()
+    {
+        return '<span>' . parent::toHtml() . '</span>';
+    }
+
+    /**
+     * Returns the disabled field. Accessibility: the return "[ ]" from parent
+     * class is not acceptable for screenreader users, and we DO want a label.
+     *
+     * @return string
+     */
+    function getFrozenHtml()
+    {
+        //$this->_generateId();
+        $output = '<input type="checkbox" disabled="disabled" id="'.$this->getAttribute('id').'" ';
+        if ($this->getChecked()) {
+            $output .= 'checked="checked" />'.$this->_getPersistantData();
+        } else {
+            $output .= '/>';
+        }
+        return $output;
+    }
+
+    public function export_for_template(renderer_base $output) {
+        $context = $this->export_for_template_base($output);
+        $context['frozenvalue'] = $this->getValue();
+        return $context;
+    }
+}

lib/form/choicedropdown.php

@@ -0,0 +1,210 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+defined('MOODLE_INTERNAL') || die();
+
+use core\output\choicelist;
+use core\output\local\dropdown\status;
+
+require_once('HTML/QuickForm/select.php');
+require_once('templatable_form_element.php');
+
+/**
+ * User choice using a dropdown type form element.
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2023 Ferran Recio <ferran@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_choicedropdown extends HTML_QuickForm_select implements templatable {
+
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+
+    /**
+     * @var string html for help button, if empty then no help.
+     */
+    protected string $_helpbutton = '';
+
+    /**
+     * @var bool if true label will be hidden.
+     */
+    protected bool $_hiddenLabel = false;
+
+    /**
+     * @var choicelist the user choices.
+     */
+    protected ?choicelist $choice = null;
+
+    /**
+     * @var string[] Dropdown dialog width.
+     */
+    public const WIDTH = status::WIDTH;
+
+    /**
+     * @var string the dropdown width (from core\output\local\dropdown\status::WIDTH).
+     */
+    protected string $dropdownwidth = status::WIDTH['small'];
+
+    /**
+     * Constructor.
+     *
+     * @param string $elementname Select name attribute
+     * @param mixed $elementlabel Label(s) for the select
+     * @param choicelist $options Data to be used to populate options
+     * @param mixed $attributes Either a typical HTML attribute string or an associative array
+     */
+    public function __construct(
+        $elementname = null,
+        $elementlabel = null,
+        choicelist $options = null,
+        $attributes = null
+    ) {
+        parent::__construct($elementname, $elementlabel, $options, $attributes);
+        $this->_type = 'choicedropdown';
+    }
+
+    /**
+     * Set the dropdown width.
+     *
+     * @param string $width
+     */
+    public function set_dialog_width(string $width) {
+        $this->dropdownwidth = $width;
+    }
+
+    /**
+     * Loads options from a choicelist.
+     *
+     * @param choicelist $choice Options source currently supports assoc array or DB_result
+     * @param string|null $value optional value (in case it is not defined in the choicelist)
+     * @param string|null $unused2 unused
+     * @param string|null $unused3 unused
+     * @param string|null $unused4 unused
+     * @return bool
+     */
+    public function load(&$choice, $value = null, $unused2 = null, $unused3 = null, $unused4 = null): bool {
+        if (!$choice instanceof choicelist) {
+            throw new coding_exception('Choice must be instance of choicelist');
+        }
+        $this->choice = $choice;
+        $this->choice->set_allow_empty(false);
+        if ($value !== null && is_string($value)) {
+            $choice->set_selected_value($value);
+        }
+        $this->setSelected($choice->get_selected_value());
+        return true;
+    }
+
+    /**
+     * Sets label to be hidden
+     *
+     * @param bool $hiddenLabel sets if label should be hidden
+     */
+    public function setHiddenLabel($hiddenLabel) {
+        $this->_hiddenLabel = $hiddenLabel;
+    }
+
+    /**
+     * Returns HTML for select form element.
+     *
+     * This method is only needed when forms renderer is forces via
+     * $GLOBALS['_HTML_QuickForm_default_renderer']. Otherwise the
+     * renderer will use mustache templates.
+     *
+     * @return string
+     */
+    public function toHtml(): string {
+        $html = '';
+        if ($this->_hiddenLabel) {
+            $this->_generateId();
+            $html .= '<label class="accesshide" for="'.$this->getAttribute('id').'" >'.$this->getLabel().'</label>';
+        }
+        $html .= parent::toHtml();
+        return $html;
+    }
+
+    /**
+     * get html for help button
+     *
+     * @return string html for help button
+     */
+    public function getHelpButton(): string {
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Slightly different container template when frozen. Don't want to use a label tag
+     * with a for attribute in that case for the element label but instead use a div.
+     * Templates are defined in renderer constructor.
+     *
+     * @return string
+     */
+    public function getElementTemplateType(): string {
+        if ($this->_flagFrozen) {
+            return 'static';
+        } else {
+            return 'default';
+        }
+    }
+
+    /**
+     * We check the options and return only the values that _could_ have been
+     * selected. We also return a scalar value if select is not "multiple"
+     *
+     * @param string $submitvalues submitted values
+     * @param bool $assoc if true the returned value is associated array
+     * @return string|null
+     */
+    public function exportValue(&$submitvalues, $assoc = false) {
+        $value = $this->_findValue($submitvalues) ?? $this->getValue();
+        if (is_array($value)) {
+            $value = reset($value);
+        }
+        if ($value === null) {
+            return $this->_prepareValue($value, $assoc);
+        }
+        if (!$this->choice->has_value($value)) {
+            $value = $this->choice->get_selected_value();
+        }
+        return $this->_prepareValue($value, $assoc);
+    }
+
+    public function export_for_template(renderer_base $output): array {
+        $context = $this->export_for_template_base($output);
+
+        if (!empty($this->_values)) {
+            $this->choice->set_selected_value(reset($this->_values));
+        }
+
+        $dialog = new status(
+            $this->choice->get_selected_content($output),
+            $this->choice,
+            [
+                'extras' => ['data-form-controls' => $context['id']],
+                'buttonsync' => true,
+                'updatestatus' => true,
+                'dialogwidth' => $this->dropdownwidth,
+            ]
+        );
+        $context['dropdown'] = $dialog->export_for_template($output);
+        $context['select'] = $this->choice->export_for_template($output);
+        $context['nameraw'] = $this->getName();
+        return $context;
+    }
+}

lib/form/classes/dynamic_form.php

@@ -0,0 +1,149 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace core_form;
+
+use context;
+use core_external\external_api;
+use moodle_url;
+
+defined('MOODLE_INTERNAL') || die();
+
+global $CFG;
+require_once($CFG->libdir . '/formslib.php');
+
+/**
+ * Class modal
+ *
+ * Extend this class to create a form that can be used in a modal dialogue.
+ *
+ * @package     core_form
+ * @copyright   2020 Marina Glancy
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+abstract class dynamic_form extends \moodleform {
+
+    /**
+     * Constructor for modal forms can not be overridden, however the same form can be used both in AJAX and normally
+     *
+     * @param string $action
+     * @param array $customdata
+     * @param string $method
+     * @param string $target
+     * @param array $attributes
+     * @param bool $editable
+     * @param array $ajaxformdata Forms submitted via ajax, must pass their data here, instead of relying on _GET and _POST.
+     * @param bool $isajaxsubmission whether the form is called from WS and it needs to validate user access and set up context
+     */
+    final public function __construct(
+        ?string $action = null,
+        ?array $customdata = null,
+        string $method = 'post',
+        string $target = '',
+        ?array $attributes = [],
+        bool $editable = true,
+        ?array $ajaxformdata = null,
+        bool $isajaxsubmission = false
+    ) {
+        global $PAGE, $CFG;
+
+        $this->_ajaxformdata = $ajaxformdata;
+        if ($isajaxsubmission) {
+            // This form was created from the WS that needs to validate user access to it and set page context.
+            // It has to be done before calling parent constructor because elements definitions may need to use
+            // format_string functions and other methods that expect the page to be set up.
+            external_api::validate_context($this->get_context_for_dynamic_submission());
+            $PAGE->set_url($this->get_page_url_for_dynamic_submission());
+            $this->check_access_for_dynamic_submission();
+        }
+        $attributes = ['data-random-ids' => 1] + ($attributes ?: []);
+        parent::__construct($action, $customdata, $method, $target, $attributes, $editable, $ajaxformdata);
+    }
+
+    /**
+     * Returns context where this form is used
+     *
+     * This context is validated in {@see external_api::validate_context()}
+     *
+     * If context depends on the form data, it is available in $this->_ajaxformdata or
+     * by calling $this->optional_param()
+     *
+     * Example:
+     *     $cmid = $this->optional_param('cmid', 0, PARAM_INT);
+     *     return context_module::instance($cmid);
+     *
+     * @return context
+     */
+    abstract protected function get_context_for_dynamic_submission(): context;
+
+    /**
+     * Checks if current user has access to this form, otherwise throws exception
+     *
+     * Sometimes permission check may depend on the action and/or id of the entity.
+     * If necessary, form data is available in $this->_ajaxformdata or
+     * by calling $this->optional_param()
+     *
+     * Example:
+     *     require_capability('dosomething', $this->get_context_for_dynamic_submission());
+     */
+    abstract protected function check_access_for_dynamic_submission(): void;
+
+    /**
+     * Process the form submission, used if form was submitted via AJAX
+     *
+     * This method can return scalar values or arrays that can be json-encoded, they will be passed to the caller JS.
+     *
+     * Submission data can be accessed as: $this->get_data()
+     *
+     * Example:
+     *     $data = $this->get_data();
+     *     file_postupdate_standard_filemanager($data, ....);
+     *     api::save_entity($data); // Save into the DB, trigger event, etc.
+     *
+     * @return mixed
+     */
+    abstract public function process_dynamic_submission();
+
+    /**
+     * Load in existing data as form defaults
+     *
+     * Can be overridden to retrieve existing values from db by entity id and also
+     * to preprocess editor and filemanager elements
+     *
+     * Example:
+     *     $id = $this->optional_param('id', 0, PARAM_INT);
+     *     $data = api::get_entity($id); // For example, retrieve a row from the DB.
+     *     file_prepare_standard_filemanager($data, ...);
+     *     $this->set_data($data);
+     */
+    abstract public function set_data_for_dynamic_submission(): void;
+
+    /**
+     * Returns url to set in $PAGE->set_url() when form is being rendered or submitted via AJAX
+     *
+     * This is used in the form elements sensitive to the page url, such as Atto autosave in 'editor'
+     *
+     * If the form has arguments (such as 'id' of the element being edited), the URL should
+     * also have respective argument.
+     *
+     * Example:
+     *     $id = $this->optional_param('id', 0, PARAM_INT);
+     *     return new moodle_url('/my/page/where/form/is/used.php', ['id' => $id]);
+     *
+     * @return moodle_url
+     */
+    abstract protected function get_page_url_for_dynamic_submission(): moodle_url;
+}

lib/form/classes/external.php

@@ -0,0 +1,104 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Provides the {@link core_form\external} class.
+ *
+ * @package     core_form
+ * @category    external
+ * @copyright   2017 David Mudrák <david@moodle.com>
+ * @copyright   2016 Jonathon Fowler <fowlerj@usq.edu.au>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_form;
+
+use core_external\external_api;
+use core_external\external_function_parameters;
+use core_external\external_multiple_structure;
+use core_external\external_single_structure;
+use core_external\external_value;
+
+/**
+ * Implements the external functions provided by the core_form subsystem.
+ *
+ * @copyright 2017 David Mudrak <david@moodle.com>
+ * @copyright 2016 Jonathon Fowler <fowlerj@usq.edu.au>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class external extends external_api {
+
+    /**
+     * Describes the input paramaters of the get_filetypes_browser_data external function.
+     *
+     * @return \core_external\external_description
+     */
+    public static function get_filetypes_browser_data_parameters() {
+        return new external_function_parameters([
+            'onlytypes' => new external_value(PARAM_RAW, 'Limit the browser to the given groups and extensions', VALUE_DEFAULT, ''),
+            'allowall' => new external_value(PARAM_BOOL, 'Allows to select All file types, does not apply with onlytypes are set.',
+                VALUE_DEFAULT, true),
+            'current' => new external_value(PARAM_RAW, 'Current types that should be selected.', VALUE_DEFAULT, ''),
+        ]);
+    }
+
+    /**
+     * Implements the get_filetypes_browser_data external function.
+     *
+     * @param string $onlytypes Allow selection from these file types only; for example 'web_image'.
+     * @param bool $allowall Allow to select 'All file types'. Does not apply if onlytypes is set.
+     * @param string $current Current values that should be selected.
+     * @return object
+     */
+    public static function get_filetypes_browser_data($onlytypes, $allowall, $current) {
+
+        $params = self::validate_parameters(self::get_filetypes_browser_data_parameters(),
+            compact('onlytypes', 'allowall', 'current'));
+
+        $util = new filetypes_util();
+
+        return ['groups' => $util->data_for_browser($params['onlytypes'], $params['allowall'], $params['current'])];
+    }
+
+    /**
+     * Describes the output of the get_filetypes_browser_data external function.
+     *
+     * @return \core_external\external_description
+     */
+    public static function get_filetypes_browser_data_returns() {
+
+        $type = new external_single_structure([
+            'key' => new external_value(PARAM_RAW, 'The file type identifier'),
+            'name' => new external_value(PARAM_RAW, 'The file type name'),
+            'selected' => new external_value(PARAM_BOOL, 'Should it be marked as selected'),
+            'ext' => new external_value(PARAM_RAW, 'The file extension associated with the file type'),
+        ]);
+
+        $group = new external_single_structure([
+            'key' => new external_value(PARAM_RAW, 'The file type group identifier'),
+            'name' => new external_value(PARAM_RAW, 'The file type group name'),
+            'selectable' => new external_value(PARAM_BOOL, 'Can it be marked as selected'),
+            'selected' => new external_value(PARAM_BOOL, 'Should it be marked as selected'),
+            'ext' => new external_value(PARAM_RAW, 'The list of file extensions associated with the group'),
+            'expanded' => new external_value(PARAM_BOOL, 'Should the group start as expanded or collapsed'),
+            'types' => new external_multiple_structure($type, 'List of file types in the group'),
+        ]);
+
+        return new external_single_structure([
+            'groups' => new external_multiple_structure($group, 'List of file type groups'),
+        ]);
+    }
+}

lib/form/classes/external/dynamic_form.php

@@ -0,0 +1,127 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace core_form\external;
+
+use core_external\external_api;
+use core_external\external_function_parameters;
+use core_external\external_single_structure;
+use core_external\external_value;
+
+/**
+ * Implements the external functions provided by the core_form subsystem.
+ *
+ * @copyright 2020 Marina Glancy
+ * @package   core_form
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class dynamic_form extends external_api {
+
+    /**
+     * Parameters for modal form
+     *
+     * @return external_function_parameters
+     */
+    public static function execute_parameters(): external_function_parameters {
+        return new external_function_parameters([
+            'form' => new external_value(PARAM_RAW_TRIMMED, 'Form class', VALUE_REQUIRED),
+            'formdata' => new external_value(PARAM_RAW, 'url-encoded form data', VALUE_REQUIRED),
+        ]);
+    }
+
+    /**
+     * Submit a form from a modal dialogue.
+     *
+     * @param string $formclass
+     * @param string $formdatastr
+     * @return array
+     * @throws \moodle_exception
+     */
+    public static function execute(string $formclass, string $formdatastr): array {
+        global $PAGE, $OUTPUT;
+
+        $params = self::validate_parameters(self::execute_parameters(), [
+            'form' => $formclass,
+            'formdata' => $formdatastr,
+        ]);
+        $formclass = $params['form'];
+        parse_str($params['formdata'], $formdata);
+
+        self::autoload_block_edit_form($formclass);
+
+        if (!class_exists($formclass) || !is_subclass_of($formclass, \core_form\dynamic_form::class)) {
+            // For security reason we don't throw exception "class does not exist" but rather an access exception.
+            throw new \moodle_exception('nopermissionform', 'core_form');
+        }
+
+        /** @var \core_form\dynamic_form $form */
+        $form = new $formclass(null, null, 'post', '', [], true, $formdata, true);
+        $form->set_data_for_dynamic_submission();
+        if (!$form->is_cancelled() && $form->is_submitted() && $form->is_validated()) {
+            // Form was properly submitted, process and return results of processing. No need to render it again.
+            return ['submitted' => true, 'data' => json_encode($form->process_dynamic_submission())];
+        }
+
+        // Render actual form.
+
+        if ($form->no_submit_button_pressed()) {
+            // If form has not been submitted, we have to recreate the form for being able to properly handle non-submit action
+            // like "repeat elements" to include additional JS.
+            /** @var \core_form\dynamic_form $form */
+            $form = new $formclass(null, null, 'post', '', [], true, $formdata, true);
+            $form->set_data_for_dynamic_submission();
+        }
+        // Hack alert: Forcing bootstrap_renderer to initiate moodle page.
+        $OUTPUT->header();
+
+        $PAGE->start_collecting_javascript_requirements();
+        $data = $form->render();
+        $jsfooter = $PAGE->requires->get_end_code();
+        $output = ['submitted' => false, 'html' => $data, 'javascript' => $jsfooter];
+        return $output;
+    }
+
+    /**
+     * Special autoloading for block forms.
+     *
+     * @param string $formclass
+     * @return void
+     */
+    protected static function autoload_block_edit_form(string $formclass): void {
+        global $CFG;
+        if (preg_match('/^block_([\w_]+)_edit_form$/', $formclass, $matches)) {
+            \block_manager::get_block_edit_form_class($matches[1]);
+        }
+        if ($formclass === 'block_edit_form') {
+            require_once($CFG->dirroot . '/blocks/edit_form.php');
+        }
+    }
+
+    /**
+     * Return for modal
+     * @return external_single_structure
+     */
+    public static function execute_returns(): external_single_structure {
+        return new external_single_structure(
+            array(
+                'submitted' => new external_value(PARAM_BOOL, 'If form was submitted and validated'),
+                'data' => new external_value(PARAM_RAW, 'JSON-encoded return data from form processing method', VALUE_OPTIONAL),
+                'html' => new external_value(PARAM_RAW, 'HTML fragment of the form', VALUE_OPTIONAL),
+                'javascript' => new external_value(PARAM_RAW, 'JavaScript fragment of the form', VALUE_OPTIONAL)
+            )
+        );
+    }
+}

lib/form/classes/filetypes_util.php

@@ -0,0 +1,537 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Provides the {@link core_form\filetypes_util} class.
+ *
+ * @package     core_form
+ * @copyright   2017 David Mudrák <david@moodle.com>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_form;
+
+use core_collator;
+use core_filetypes;
+use core_text;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Utility class for handling with file types in the forms.
+ *
+ * This class is supposed to serve as a helper class for {@link MoodleQuickForm_filetypes}
+ * and {@link admin_setting_filetypes} classes.
+ *
+ * The file types can be specified in a syntax compatible with what filepicker
+ * and filemanager support via the "accepted_types" option: a list of extensions
+ * (e.g. ".doc"), mimetypes ("image/png") or groups ("audio").
+ *
+ * @copyright 2017 David Mudrak <david@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class filetypes_util {
+
+    /** @var array Cache of all file type groups for the {@link self::get_groups_info()}. */
+    protected $cachegroups = null;
+
+    /**
+     * Converts the argument into an array (list) of file types.
+     *
+     * The list can be separated by whitespace, end of lines, commas, colons and semicolons.
+     * Empty values are not returned. Values are converted to lowercase.
+     * Duplicates are removed. Glob evaluation is not supported.
+     *
+     * The return value can be used as the accepted_types option for the filepicker.
+     *
+     * @param string|array $types List of file extensions, groups or mimetypes
+     * @return array of strings
+     */
+    public function normalize_file_types($types) {
+
+        if ($types === '' || $types === null) {
+            return [];
+        }
+
+        // Turn string into a list.
+        if (!is_array($types)) {
+            $types = preg_split('/[\s,;:"\']+/', $types, -1, PREG_SPLIT_NO_EMPTY);
+        }
+
+        // Fix whitespace and normalize the syntax a bit.
+        foreach ($types as $i => $type) {
+            $type = str_replace('*.', '.', $type);
+            $type = core_text::strtolower($type);
+            $type = trim($type);
+
+            if ($type === '*') {
+                return ['*'];
+            }
+
+            $types[$i] = $type;
+        }
+
+        // Do not make the user think that globs (like ".doc?") would work.
+        foreach ($types as $i => $type) {
+            if (strpos($type, '*') !== false or strpos($type, '?') !== false) {
+                unset($types[$i]);
+            }
+        }
+
+        foreach ($types as $i => $type) {
+            if (substr($type, 0, 1) === '.') {
+                // It looks like an extension.
+                $type = '.'.ltrim($type, '.');
+                $types[$i] = clean_param($type, PARAM_FILE);
+            } else if ($this->looks_like_mimetype($type)) {
+                // All good, it looks like a mimetype.
+                continue;
+            } else if ($this->is_filetype_group($type)) {
+                // All good, it is a known type group.
+                continue;
+            } else {
+                // We assume the user typed something like "png" so we consider
+                // it an extension.
+                $types[$i] = '.'.$type;
+            }
+        }
+
+        $types = array_filter($types, 'strlen');
+        $types = array_keys(array_flip($types));
+
+        return $types;
+    }
+
+    /**
+     * Does the given file type looks like a valid MIME type?
+     *
+     * This does not check of the MIME type is actually registered here/known.
+     *
+     * @param string $type
+     * @return bool
+     */
+    public function looks_like_mimetype($type) {
+        return (bool)preg_match('~^[-\.a-z0-9]+/[a-z0-9]+([-\.\+][a-z0-9]+)*$~', $type);
+    }
+
+    /**
+     * Is the given string a known filetype group?
+     *
+     * @param string $type
+     * @return bool|object false or the group info
+     */
+    public function is_filetype_group($type) {
+
+        $info = $this->get_groups_info();
+
+        if (isset($info[$type])) {
+            return $info[$type];
+
+        } else {
+            return false;
+        }
+    }
+
+    /**
+     * Provides a list of all known file type groups and their properties.
+     *
+     * @return array
+     */
+    public function get_groups_info() {
+
+        if ($this->cachegroups !== null) {
+            return $this->cachegroups;
+        }
+
+        $groups = [];
+
+        foreach (core_filetypes::get_types() as $ext => $info) {
+            if (isset($info['groups']) && is_array($info['groups'])) {
+                foreach ($info['groups'] as $group) {
+                    if (!isset($groups[$group])) {
+                        $groups[$group] = (object) [
+                            'extensions' => [],
+                            'mimetypes' => [],
+                        ];
+                    }
+                    $groups[$group]->extensions['.'.$ext] = true;
+                    if (isset($info['type'])) {
+                        $groups[$group]->mimetypes[$info['type']] = true;
+                    }
+                }
+            }
+        }
+
+        foreach ($groups as $group => $info) {
+            $info->extensions = array_keys($info->extensions);
+            $info->mimetypes = array_keys($info->mimetypes);
+        }
+
+        $this->cachegroups = $groups;
+        return $this->cachegroups;
+    }
+
+    /**
+     * Return a human readable name of the filetype group.
+     *
+     * @param string $group
+     * @return string
+     */
+    public function get_group_description($group) {
+
+        if (get_string_manager()->string_exists('group:'.$group, 'core_mimetypes')) {
+            return get_string('group:'.$group, 'core_mimetypes');
+        } else {
+            return s($group);
+        }
+    }
+
+    /**
+     * Describe the list of file types for human user.
+     *
+     * Given the list of file types, return a list of human readable
+     * descriptive names of relevant groups, types or file formats.
+     *
+     * @param string|array $types
+     * @return object
+     */
+    public function describe_file_types($types) {
+
+        $descriptions = [];
+        $types = $this->normalize_file_types($types);
+
+        foreach ($types as $type) {
+            if ($type === '*') {
+                $desc = get_string('filetypesany', 'core_form');
+                $descriptions[$desc] = [];
+            } else if ($group = $this->is_filetype_group($type)) {
+                $desc = $this->get_group_description($type);
+                $descriptions[$desc] = $group->extensions;
+
+            } else if ($this->looks_like_mimetype($type)) {
+                $desc = get_mimetype_description($type);
+                $descriptions[$desc] = file_get_typegroup('extension', [$type]);
+
+            } else {
+                $desc = get_mimetype_description(['filename' => 'fakefile'.$type]);
+                if (isset($descriptions[$desc])) {
+                    $descriptions[$desc][] = $type;
+                } else {
+                    $descriptions[$desc] = [$type];
+                }
+            }
+        }
+
+        $data = [];
+
+        foreach ($descriptions as $desc => $exts) {
+            sort($exts);
+            $data[] = (object)[
+                'description' => $desc,
+                'extensions' => join(' ', $exts),
+            ];
+        }
+
+        core_collator::asort_objects_by_property($data, 'description', core_collator::SORT_NATURAL);
+
+        return (object)[
+            'hasdescriptions' => !empty($data),
+            'descriptions' => array_values($data),
+        ];
+    }
+
+    /**
+     * Prepares data for the filetypes-browser.mustache
+     *
+     * @param string|array $onlytypes Allow selection from these file types only; for example 'web_image'.
+     * @param bool $allowall Allow to select 'All file types'. Does not apply with onlytypes are set.
+     * @param string|array $current Current values that should be selected.
+     * @return array
+     */
+    public function data_for_browser($onlytypes=null, $allowall=true, $current=null) {
+
+        $groups = [];
+        $current = $this->normalize_file_types($current);
+
+        // Firstly populate the tree of extensions categorized into groups.
+
+        foreach ($this->get_groups_info() as $groupkey => $groupinfo) {
+            if (empty($groupinfo->extensions)) {
+                continue;
+            }
+
+            $group = (object) [
+                'key' => $groupkey,
+                'name' => $this->get_group_description($groupkey),
+                'selectable' => true,
+                'selected' => in_array($groupkey, $current),
+                'ext' => implode(' ', $groupinfo->extensions),
+                'expanded' => false,
+            ];
+
+            $types = [];
+
+            foreach ($groupinfo->extensions as $extension) {
+                if ($onlytypes && !$this->is_listed($extension, $onlytypes)) {
+                    $group->selectable = false;
+                    $group->expanded = true;
+                    $group->ext = '';
+                    continue;
+                }
+
+                $desc = get_mimetype_description(['filename' => 'fakefile'.$extension]);
+
+                if ($selected = in_array($extension, $current)) {
+                    $group->expanded = true;
+                }
+
+                $types[] = (object) [
+                    'key' => $extension,
+                    'name' => get_mimetype_description(['filename' => 'fakefile'.$extension]),
+                    'selected' => $selected,
+                    'ext' => $extension,
+                ];
+            }
+
+            if (empty($types)) {
+                continue;
+            }
+
+            core_collator::asort_objects_by_property($types, 'name', core_collator::SORT_NATURAL);
+
+            $group->types = array_values($types);
+            $groups[] = $group;
+        }
+
+        core_collator::asort_objects_by_property($groups, 'name', core_collator::SORT_NATURAL);
+
+        // Append all other uncategorized extensions.
+
+        $others = [];
+
+        foreach (core_filetypes::get_types() as $extension => $info) {
+            // Reserved for unknown file types. Not available here.
+            if ($extension === 'xxx') {
+                continue;
+            }
+            $extension = '.'.$extension;
+            if ($onlytypes && !$this->is_listed($extension, $onlytypes)) {
+                continue;
+            }
+            if (!isset($info['groups']) || empty($info['groups'])) {
+                $others[] = (object) [
+                    'key' => $extension,
+                    'name' => get_mimetype_description(['filename' => 'fakefile'.$extension]),
+                    'selected' => in_array($extension, $current),
+                    'ext' => $extension,
+                ];
+            }
+        }
+
+        core_collator::asort_objects_by_property($others, 'name', core_collator::SORT_NATURAL);
+
+        if (!empty($others)) {
+            $groups[] = (object) [
+                'key' => '',
+                'name' => get_string('filetypesothers', 'core_form'),
+                'selectable' => false,
+                'selected' => false,
+                'ext' => '',
+                'types' => array_values($others),
+                'expanded' => true,
+            ];
+        }
+
+        if (empty($onlytypes) and $allowall) {
+            array_unshift($groups, (object) [
+                'key' => '*',
+                'name' => get_string('filetypesany', 'core_form'),
+                'selectable' => true,
+                'selected' => in_array('*', $current),
+                'ext' => null,
+                'types' => [],
+                'expanded' => false,
+            ]);
+        }
+
+        $groups = array_values($groups);
+
+        return $groups;
+    }
+
+    /**
+     * Expands the file types into the list of file extensions.
+     *
+     * The groups and mimetypes are expanded into the list of their associated file
+     * extensions. Depending on the $keepgroups and $keepmimetypes, the groups
+     * and mimetypes themselves are either kept in the list or removed.
+     *
+     * @param string|array $types
+     * @param bool $keepgroups Keep the group item in the list after expansion
+     * @param bool $keepmimetypes Keep the mimetype item in the list after expansion
+     * @return array list of extensions and eventually groups and types
+     */
+    public function expand($types, $keepgroups=false, $keepmimetypes=false) {
+
+        $expanded = [];
+
+        foreach ($this->normalize_file_types($types) as $type) {
+            if ($group = $this->is_filetype_group($type)) {
+                foreach ($group->extensions as $ext) {
+                    $expanded[$ext] = true;
+                }
+                if ($keepgroups) {
+                    $expanded[$type] = true;
+                }
+
+            } else if ($this->looks_like_mimetype($type)) {
+                // A mime type expands to the associated extensions.
+                foreach (file_get_typegroup('extension', [$type]) as $ext) {
+                    $expanded[$ext] = true;
+                }
+                if ($keepmimetypes) {
+                    $expanded[$type] = true;
+                }
+
+            } else {
+                // Single extension expands to itself.
+                $expanded[$type] = true;
+            }
+        }
+
+        return array_keys($expanded);
+    }
+
+    /**
+     * Should the file type be considered as a part of the given list.
+     *
+     * If multiple types are provided, all of them must be part of the list. Empty type is part of any list.
+     * Any type is part of an empty list.
+     *
+     * @param string|array $types File type or list of types to be checked.
+     * @param string|array $list An array or string listing the types to check against.
+     * @return boolean
+     */
+    public function is_listed($types, $list) {
+        return empty($this->get_not_listed($types, $list));
+    }
+
+    /**
+     * @deprecated since Moodle 3.10 MDL-69050 - please use {@see is_listed} instead.
+     */
+    public function is_whitelisted() {
+        throw new \coding_exception('\core_form\filetypes_util::is_whitelisted() has been removed.');
+    }
+
+    /**
+     * Returns all types that are not part of the given list.
+     *
+     * This is similar check to the {@see self::is_listed()} but this one actually returns the extra types.
+     *
+     * @param string|array $types File type or list of types to be checked.
+     * @param string|array $list An array or string listing the types to check against.
+     * @return array Types not present in the list.
+     */
+    public function get_not_listed($types, $list) {
+
+        $listedtypes = $this->expand($list, true, true);
+
+        if (empty($listedtypes) || $listedtypes == ['*']) {
+            return [];
+        }
+
+        $giventypes = $this->normalize_file_types($types);
+
+        if (empty($giventypes)) {
+            return [];
+        }
+
+        return array_diff($giventypes, $listedtypes);
+    }
+
+    /**
+     * @deprecated since Moodle 3.10 MDL-69050 - please use {@see get_not_listed} instead.
+     */
+    public function get_not_whitelisted() {
+        throw new \coding_exception('\core_form\filetypes_util::get_not_whitelisted() has been removed.');
+    }
+
+    /**
+     * Is the given filename of an allowed file type?
+     *
+     * Empty allowlist is interpreted as "any file type is allowed" rather
+     * than "no file can be uploaded".
+     *
+     * @param string $filename the file name
+     * @param string|array $allowlist list of allowed file extensions
+     * @return boolean True if the file type is allowed, false if not
+     */
+    public function is_allowed_file_type($filename, $allowlist) {
+
+        $allowedextensions = $this->expand($allowlist);
+
+        if (empty($allowedextensions) || $allowedextensions == ['*']) {
+            return true;
+        }
+
+        $haystack = strrev(trim(core_text::strtolower($filename)));
+
+        foreach ($allowedextensions as $extension) {
+            if (strpos($haystack, strrev($extension)) === 0) {
+                // The file name ends with the extension.
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Returns file types from the list that are not recognized
+     *
+     * @param string|array $types list of user-defined file types
+     * @return array A list of unknown file types.
+     */
+    public function get_unknown_file_types($types) {
+        $unknown = [];
+
+        foreach ($this->normalize_file_types($types) as $type) {
+            if ($type === '*') {
+                // Any file is considered as a known type.
+                continue;
+            } else if ($type === '.xxx') {
+                $unknown[$type] = true;
+            } else if ($this->is_filetype_group($type)) {
+                // The type is a group that exists.
+                continue;
+            } else if ($this->looks_like_mimetype($type)) {
+                // If there's no extension associated with that mimetype, we consider it unknown.
+                if (empty(file_get_typegroup('extension', [$type]))) {
+                    $unknown[$type] = true;
+                }
+            } else {
+                $coretypes = core_filetypes::get_types();
+                $typecleaned = str_replace(".", "", $type);
+                if (empty($coretypes[$typecleaned])) {
+                    // If there's no extension, it doesn't exist.
+                    $unknown[$type] = true;
+                }
+            }
+        }
+
+        return array_keys($unknown);
+    }
+}

lib/form/classes/privacy/provider.php

@@ -0,0 +1,86 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Provides {@link \core_form\privacy\provider} class.
+ *
+ * @package     core_form
+ * @category    privacy
+ * @copyright   2018 David Mudrák <david@moodle.com>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_form\privacy;
+
+use core_privacy\local\metadata\collection;
+use core_privacy\local\request\writer;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Implements the privacy API for the core_form subsystem.
+ *
+ * @package   core_files
+ * @copyright 2018 David Mudrák <david@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class provider implements
+        // The forms subsystem does not store any data itself, it has no database tables.
+        \core_privacy\local\metadata\provider,
+
+        // The forms subsystem has user preferences.
+        \core_privacy\local\request\user_preference_provider {
+
+    /**
+     * Returns meta data about this system.
+     *
+     * @param collection $collection The initialised collection to add items to.
+     * @return collection A listing of user data stored through this system.
+     */
+    public static function get_metadata(collection $collection): collection {
+
+        $collection->add_user_preference('filemanager_recentviewmode', 'privacy:metadata:preference:filemanager_recentviewmode');
+
+        return $collection;
+    }
+
+    /**
+     * Export all user preferences for the subsystem.
+     *
+     * @param int $userid The ID of the user whose data is to be exported.
+     */
+    public static function export_user_preferences(int $userid) {
+        $preference = get_user_preferences('filemanager_recentviewmode', null, $userid);
+        if ($preference !== null) {
+            switch ($preference) {
+                case 1:
+                    $value = get_string('displayasicons', 'core_repository');
+                    break;
+                case 2:
+                    $value = get_string('displayastree', 'core_repository');
+                    break;
+                case 3:
+                    $value = get_string('displaydetails', 'core_repository');
+                    break;
+                default:
+                    $value = $preference;
+            }
+
+            $desc = get_string('privacy:preference:filemanager_recentviewmode', 'core_form', $value);
+            writer::export_user_preference('core_form', 'filemanager_recentviewmode', $preference, $desc);
+        }
+    }
+}

lib/form/classes/util.php

@@ -0,0 +1,64 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Provides the {@link core_form\util} class.
+ *
+ * @package core_form
+ * @copyright 2019 The Open University
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_form;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * General utility class for form-related methods.
+ *
+ * @copyright 2019 The Open University
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class util {
+    /**
+     * This function should be called if a form submit results in a file download (i.e. with the
+     * Content-Disposition: attachment header) instead of navigating to a new page, before the
+     * file download is sent. It will set a cookie which is used to inform page javascript in
+     * submit.js.
+     *
+     * You may call this function in scripts which might not necessarily be called from forms; it
+     * will only set the cookie if there is a POST request from a form.
+     *
+     * This is automatically called from various points in Moodle such as send_file_xx functions
+     * in filelib.php.
+     */
+    public static function form_download_complete() {
+        // If this doesn't look like a Moodle QuickForms request, ignore.
+        $quickform = false;
+        foreach ($_POST as $name => $value) {
+            if (preg_match('~^_qf__~', $name)) {
+                $quickform = true;
+                break;
+            }
+        }
+        if (!$quickform) {
+            return;
+        }
+
+        // Set a session cookie.
+        setcookie('moodledownload_' . sesskey(), time());
+    }
+}

lib/form/cohort.php

@@ -0,0 +1,151 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Course selector field.
+ *
+ * Allows auto-complete ajax searching for cohort.
+ *
+ * @package   core_form
+ * @copyright 2015 Damyon Wiese <damyon@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+require_once($CFG->libdir . '/form/autocomplete.php');
+require_once($CFG->dirroot . '/cohort/lib.php');
+
+/**
+ * Form field type for choosing a cohort.
+ *
+ * Allows auto-complete ajax searching for cohort.
+ *
+ * @package   core_form
+ * @copyright 2016 Damyon Wiese <damyon@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_cohort extends MoodleQuickForm_autocomplete {
+
+    /**
+     * @var array $exclude Exclude a list of cohorts from the list (e.g. the current cohort).
+     */
+    protected $exclude = array();
+
+    /**
+     * @var int $contextid The context id to fetch cohorts in.
+     */
+    protected $contextid = 0;
+
+    /**
+     * @var boolean $allowmultiple Allow selecting more than one cohort.
+     */
+    protected $multiple = false;
+
+    /**
+     * @var array $requiredcapabilities Array of extra capabilities to check at the cohort context.
+     */
+    protected $requiredcapabilities = array();
+
+    /**
+     * Constructor
+     *
+     * @param string $elementname Element name
+     * @param mixed $elementlabel Label(s) for an element
+     * @param array $options Options to control the element's display
+     *                       Valid options are:
+     *                       'multiple' - boolean multi select
+     *                       'exclude' - array or int, list of course ids to never show
+     *                       'requiredcapabilities' - array of capabilities. Uses ANY to combine them.
+     */
+    public function __construct($elementname = null, $elementlabel = null, $options = array()) {
+        if (isset($options['multiple'])) {
+            $this->multiple = $options['multiple'];
+        }
+        if (isset($options['contextid'])) {
+            $this->contextid = $options['contextid'];
+        } else {
+            $this->contextid = context_system::instance()->id;
+        }
+        if (isset($options['exclude'])) {
+            $this->exclude = $options['exclude'];
+            if (!is_array($this->exclude)) {
+                $this->exclude = array($this->exclude);
+            }
+        }
+        if (isset($options['requiredcapabilities'])) {
+            $this->requiredcapabilities = $options['requiredcapabilities'];
+        }
+
+        $validattributes = array(
+            'ajax' => 'core/form-cohort-selector',
+            'data-exclude' => implode(',', $this->exclude),
+            'data-contextid' => (int)$this->contextid
+        );
+        if ($this->multiple) {
+            $validattributes['multiple'] = 'multiple';
+        }
+        if (isset($options['noselectionstring'])) {
+            $validattributes['noselectionstring'] = $options['noselectionstring'];
+        }
+        if (isset($options['placeholder'])) {
+            $validattributes['placeholder'] = $options['placeholder'];
+        }
+
+        parent::__construct($elementname, $elementlabel, array(), $validattributes);
+    }
+
+    /**
+     * Set the value of this element. If values can be added or are unknown, we will
+     * make sure they exist in the options array.
+     * @param string|array $value The value to set.
+     * @return boolean
+     */
+    public function setValue($value) {
+        global $DB;
+        $values = (array) $value;
+        $cohortstofetch = array();
+
+        foreach ($values as $onevalue) {
+            if ($onevalue && !$this->optionExists($onevalue) &&
+                    ($onevalue !== '_qf__force_multiselect_submission')) {
+                array_push($cohortstofetch, $onevalue);
+            }
+        }
+
+        if (empty($cohortstofetch)) {
+            $this->setSelected($values);
+            return true;
+        }
+
+        list($whereclause, $params) = $DB->get_in_or_equal($cohortstofetch, SQL_PARAMS_NAMED, 'id');
+
+        $list = $DB->get_records_select('cohort', 'id ' . $whereclause, $params, 'name');
+
+        $currentcontext = context_helper::instance_by_id($this->contextid);
+        foreach ($list as $cohort) {
+            // Make sure we can see the cohort.
+            if (!cohort_can_view_cohort($cohort, $currentcontext)) {
+                continue;
+            }
+            $label = format_string($cohort->name, true, ['context' => $currentcontext]);
+            $this->addOption($label, $cohort->id);
+        }
+
+        $this->setSelected($values);
+        return true;
+    }
+}

lib/form/course.php

@@ -0,0 +1,167 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Course selector field.
+ *
+ * Allows auto-complete ajax searching for courses and can restrict by enrolment, permissions, viewhidden...
+ *
+ * @package   core_form
+ * @copyright 2015 Damyon Wiese <damyon@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+require_once($CFG->libdir . '/form/autocomplete.php');
+
+/**
+ * Form field type for choosing a course.
+ *
+ * Allows auto-complete ajax searching for courses and can restrict by enrolment, permissions, viewhidden...
+ *
+ * @package   core_form
+ * @copyright 2015 Damyon Wiese <damyon@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_course extends MoodleQuickForm_autocomplete {
+
+    /**
+     * @var array $exclude Exclude a list of courses from the list (e.g. the current course).
+     */
+    protected $exclude = array();
+
+    /**
+     * @var boolean $allowmultiple Allow selecting more than one course.
+     */
+    protected $multiple = false;
+
+    /**
+     * @var array $requiredcapabilities Array of extra capabilities to check at the course context.
+     */
+    protected $requiredcapabilities = array();
+
+    /**
+     * @var bool $limittoenrolled Only allow enrolled courses.
+     */
+    protected $limittoenrolled = false;
+
+    /**
+     * Constructor
+     *
+     * @param string $elementname Element name
+     * @param mixed $elementlabel Label(s) for an element
+     * @param mixed $attributes Array of typical HTML attributes plus additional options, such as:
+     *                       'multiple' - boolean multi select
+     *                       'exclude' - array or int, list of course ids to never show
+     *                       'requiredcapabilities' - array of capabilities. Uses ANY to combine them.
+     *                       'limittoenrolled' - boolean Limits to enrolled courses.
+     *                       'includefrontpage' - boolean Enables the frontpage to be selected.
+     *                       'onlywithcompletion' - boolean Limits to courses where completion is enabled.
+     */
+    public function __construct($elementname = null, $elementlabel = null, $attributes = array()) {
+        if (!is_array($attributes)) {
+            $attributes = [];
+        }
+        if (isset($attributes['multiple'])) {
+            $this->multiple = $attributes['multiple'];
+        }
+        if (isset($attributes['exclude'])) {
+            $this->exclude = $attributes['exclude'];
+            if (!is_array($this->exclude)) {
+                $this->exclude = array($this->exclude);
+            }
+            unset($attributes['exclude']);
+        }
+        if (isset($attributes['requiredcapabilities'])) {
+            $this->requiredcapabilities = $attributes['requiredcapabilities'];
+            unset($attributes['requiredcapabilities']);
+        }
+        if (isset($attributes['limittoenrolled'])) {
+            $this->limittoenrolled = $attributes['limittoenrolled'];
+            unset($attributes['limittoenrolled']);
+        }
+
+        $attributes += array(
+            'ajax' => 'core/form-course-selector',
+            'data-requiredcapabilities' => implode(',', $this->requiredcapabilities),
+            'data-exclude' => implode(',', $this->exclude),
+            'data-limittoenrolled' => (int)$this->limittoenrolled
+        );
+        if (!empty($attributes['includefrontpage'])) {
+            $attributes['data-includefrontpage'] = SITEID;
+            unset($attributes['includefrontpage']);
+        }
+        if (!empty($attributes['onlywithcompletion'])) {
+            $attributes['data-onlywithcompletion'] = 1;
+            unset($attributes['onlywithcompletion']);
+        }
+
+        parent::__construct($elementname, $elementlabel, array(), $attributes);
+    }
+
+    /**
+     * Set the value of this element. If values can be added or are unknown, we will
+     * make sure they exist in the options array.
+     * @param string|array $value The value to set.
+     * @return boolean
+     */
+    public function setValue($value) {
+        global $DB;
+        $values = (array) $value;
+        $coursestofetch = array();
+
+        foreach ($values as $onevalue) {
+            if ($onevalue && !$this->optionExists($onevalue) &&
+                    ($onevalue !== '_qf__force_multiselect_submission')) {
+                array_push($coursestofetch, $onevalue);
+            }
+        }
+
+        if (empty($coursestofetch)) {
+            return $this->setSelected($values);
+        }
+
+        // There is no API function to load a list of course from a list of ids.
+        $ctxselect = context_helper::get_preload_record_columns_sql('ctx');
+        $fields = array('c.id', 'c.category', 'c.sortorder',
+                        'c.shortname', 'c.fullname', 'c.idnumber',
+                        'c.startdate', 'c.visible', 'c.cacherev');
+        list($whereclause, $params) = $DB->get_in_or_equal($coursestofetch, SQL_PARAMS_NAMED, 'id');
+
+        $sql = "SELECT ". join(',', $fields). ", $ctxselect
+                FROM {course} c
+                JOIN {context} ctx ON c.id = ctx.instanceid AND ctx.contextlevel = :contextcourse
+                WHERE c.id ". $whereclause." ORDER BY c.sortorder";
+        $list = $DB->get_records_sql($sql, array('contextcourse' => CONTEXT_COURSE) + $params);
+
+        $mycourses = enrol_get_my_courses(null, null, 0, array_keys($list));
+        $coursestoselect = array();
+        foreach ($list as $course) {
+            context_helper::preload_from_record($course);
+            $context = context_course::instance($course->id);
+            // Make sure we can see the course.
+            if (!array_key_exists($course->id, $mycourses) && !core_course_category::can_view_course_info($course)) {
+                continue;
+            }
+            $label = format_string(get_course_display_name_for_list($course), true, ['context' => $context]);
+            $this->addOption($label, $course->id);
+            array_push($coursestoselect, $course->id);
+        }
+
+        return $this->setSelected($values);
+    }
+}

lib/form/dateselector.php

@@ -0,0 +1,307 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Group of date input element
+ *
+ * Contains class for a group of elements used to input a date.
+ *
+ * @package   core_form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+require_once($CFG->libdir . '/form/group.php');
+require_once($CFG->libdir . '/formslib.php');
+
+/**
+ * Class for a group of elements used to input a date.
+ *
+ * Emulates moodle print_date_selector function
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_date_selector extends MoodleQuickForm_group {
+
+    /**
+     * Control the fieldnames for form elements.
+     *
+     * startyear => int start of range of years that can be selected
+     * stopyear => int last year that can be selected
+     * timezone => int|float|string (optional) timezone modifier used for edge case only.
+     *      If not specified, then date is caclulated based on current user timezone.
+     *      Note: dst will be calculated for string timezones only
+     *      {@link https://moodledev.io/docs/apis/subsystems/time#timezone}
+     * optional => if true, show a checkbox beside the date to turn it on (or off)
+     * @var array
+     */
+    protected $_options = array();
+
+    /**
+     * @var array These complement separators, they are appended to the resultant HTML.
+     */
+    protected $_wrap = array('', '');
+
+    /**
+     * @var null|bool Keeps track of whether the date selector was initialised using createElement
+     *                or addElement. If true, createElement was used signifying the element has been
+     *                added to a group - see MDL-39187.
+     */
+    protected $_usedcreateelement = true;
+
+    /**
+     * constructor
+     *
+     * @param string $elementName Element's name
+     * @param mixed $elementLabel Label(s) for an element
+     * @param array $options Options to control the element's display
+     * @param mixed $attributes Either a typical HTML attribute string or an associative array
+     */
+    public function __construct($elementName = null, $elementLabel = null, $options = array(), $attributes = null) {
+        // Get the calendar type used - see MDL-18375.
+        $calendartype = \core_calendar\type_factory::get_calendar_instance();
+        $this->_options = array('startyear' => $calendartype->get_min_year(), 'stopyear' => $calendartype->get_max_year(),
+            'defaulttime' => 0, 'timezone' => 99, 'step' => 1, 'optional' => false);
+        // TODO MDL-52313 Replace with the call to parent::__construct().
+        HTML_QuickForm_element::__construct($elementName, $elementLabel, $attributes);
+        $this->_persistantFreeze = true;
+        $this->_appendName = true;
+        $this->_type = 'date_selector';
+        // set the options, do not bother setting bogus ones
+        if (is_array($options)) {
+            foreach ($options as $name => $value) {
+                if (isset($this->_options[$name])) {
+                    if (is_array($value) && is_array($this->_options[$name])) {
+                        $this->_options[$name] = @array_merge($this->_options[$name], $value);
+                    } else {
+                        $this->_options[$name] = $value;
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_date_selector($elementName = null, $elementLabel = null, $options = array(), $attributes = null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $options, $attributes);
+    }
+
+    /**
+     * This will create date group element constisting of day, month and year.
+     *
+     * @access private
+     */
+    function _createElements() {
+        global $OUTPUT;
+
+        // Get the calendar type used - see MDL-18375.
+        $calendartype = \core_calendar\type_factory::get_calendar_instance();
+
+        $this->_elements = array();
+
+        $dateformat = $calendartype->get_date_order($this->_options['startyear'], $this->_options['stopyear']);
+        // Reverse date element (Day, Month, Year), in RTL mode.
+        if (right_to_left()) {
+            $dateformat = array_reverse($dateformat);
+        }
+        // If optional we add a checkbox which the user can use to turn if on.
+        if ($this->_options['optional']) {
+            $this->_elements[] = $this->createFormElement('checkbox', 'enabled', null,
+                get_string('enable'), $this->getAttributesForFormElement(), true);
+        }
+        foreach ($dateformat as $key => $value) {
+            // E_STRICT creating elements without forms is nasty because it internally uses $this
+            $this->_elements[] = $this->createFormElement('select', $key, get_string($key, 'form'), $value,
+                $this->getAttributesForFormElement(), true);
+        }
+        // The YUI2 calendar only supports the gregorian calendar type so only display the calendar image if this is being used.
+        if ($calendartype->get_name() === 'gregorian') {
+            $image = $OUTPUT->pix_icon('i/calendar', get_string('calendar', 'calendar'), 'moodle');
+            $this->_elements[] = $this->createFormElement('link', 'calendar',
+                    null, '#', $image);
+        }
+        foreach ($this->_elements as $element){
+            if (method_exists($element, 'setHiddenLabel')){
+                $element->setHiddenLabel(true);
+            }
+        }
+
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return bool
+     */
+    function onQuickFormEvent($event, $arg, &$caller) {
+        $this->setMoodleForm($caller);
+        switch ($event) {
+            case 'updateValue':
+                // Constant values override both default and submitted ones
+                // default values are overriden by submitted.
+                $value = $this->_findValue($caller->_constantValues);
+                if (null === $value) {
+                    // If no boxes were checked, then there is no value in the array
+                    // yet we don't want to display default value in this case.
+                    if ($caller->isSubmitted() && !$caller->is_new_repeat($this->getName())) {
+                        $value = $this->_findValue($caller->_submitValues);
+                    } else {
+                        $value = $this->_findValue($caller->_defaultValues);
+                    }
+                }
+                $requestvalue=$value;
+                if ($value == 0) {
+                    $value = time();
+                }
+                if (!is_array($value)) {
+                    $calendartype = \core_calendar\type_factory::get_calendar_instance();
+                    $currentdate = $calendartype->timestamp_to_date_array($value, $this->_options['timezone']);
+                    $value = array(
+                        'day' => $currentdate['mday'],
+                        'month' => $currentdate['mon'],
+                        'year' => $currentdate['year']);
+                    // If optional, default to off, unless a date was provided.
+                    if ($this->_options['optional']) {
+                        $value['enabled'] = $requestvalue != 0;
+                    }
+                } else {
+                    $value['enabled'] = isset($value['enabled']);
+                }
+                if (null !== $value) {
+                    $this->setValue($value);
+                }
+                break;
+            case 'createElement':
+                // Optional is an optional param, if its set we need to add a disabledIf rule.
+                // If its empty or not specified then its not an optional dateselector.
+                if (!empty($arg[2]['optional']) && !empty($arg[0])) {
+                    // When using the function addElement, rather than createElement, we still
+                    // enter this case, making this check necessary.
+                    if ($this->_usedcreateelement) {
+                        $caller->disabledIf($arg[0] . '[day]', $arg[0] . '[enabled]');
+                        $caller->disabledIf($arg[0] . '[month]', $arg[0] . '[enabled]');
+                        $caller->disabledIf($arg[0] . '[year]', $arg[0] . '[enabled]');
+                    } else {
+                        $caller->disabledIf($arg[0], $arg[0] . '[enabled]');
+                    }
+                }
+                return parent::onQuickFormEvent($event, $arg, $caller);
+                break;
+            case 'addElement':
+                $this->_usedcreateelement = false;
+                return parent::onQuickFormEvent($event, $arg, $caller);
+                break;
+            default:
+                return parent::onQuickFormEvent($event, $arg, $caller);
+        }
+    }
+
+    /**
+     * Returns HTML for advchecbox form element.
+     *
+     * @return string
+     */
+    function toHtml() {
+        include_once('HTML/QuickForm/Renderer/Default.php');
+        $renderer = new HTML_QuickForm_Renderer_Default();
+        $renderer->setElementTemplate('{element}');
+        parent::accept($renderer);
+
+        $html = $this->_wrap[0];
+        if ($this->_usedcreateelement) {
+            $html .= html_writer::tag('span', $renderer->toHtml(), array('class' => 'fdate_selector'));
+        } else {
+            $html .= $renderer->toHtml();
+        }
+        $html .= $this->_wrap[1];
+
+        return $html;
+    }
+
+    /**
+     * Accepts a renderer
+     *
+     * @param HTML_QuickForm_Renderer $renderer An HTML_QuickForm_Renderer object
+     * @param bool $required Whether a group is required
+     * @param string $error An error message associated with a group
+     */
+    function accept(&$renderer, $required = false, $error = null) {
+        form_init_date_js();
+        $renderer->renderElement($this, $required, $error);
+    }
+
+    /**
+     * Export for template
+     *
+     * @param renderer_base $output
+     * @return array|stdClass
+     */
+    public function export_for_template(renderer_base $output) {
+        form_init_date_js();
+        return parent::export_for_template($output);
+    }
+
+    /**
+     * Output a timestamp. Give it the name of the group.
+     *
+     * @param array $submitValues values submitted.
+     * @param bool $assoc specifies if returned array is associative
+     * @return array
+     */
+    function exportValue(&$submitValues, $assoc = false) {
+        $valuearray = array();
+        foreach ($this->_elements as $element){
+            $thisexport = $element->exportValue($submitValues[$this->getName()], true);
+            if ($thisexport!=null){
+                $valuearray += $thisexport;
+            }
+        }
+        if (count($valuearray) && isset($valuearray['year'])) {
+            if($this->_options['optional']) {
+                // If checkbox is on, the value is zero, so go no further
+                if(empty($valuearray['enabled'])) {
+                    return $this->_prepareValue(0, $assoc);
+                }
+            }
+            // Get the calendar type used - see MDL-18375.
+            $calendartype = \core_calendar\type_factory::get_calendar_instance();
+            $gregoriandate = $calendartype->convert_to_gregorian($valuearray['year'], $valuearray['month'], $valuearray['day']);
+            $value = make_timestamp($gregoriandate['year'],
+                                                      $gregoriandate['month'],
+                                                      $gregoriandate['day'],
+                                                      0, 0, 0,
+                                                      $this->_options['timezone'],
+                                                      true);
+
+            return $this->_prepareValue($value, $assoc);
+        } else {
+            return null;
+        }
+    }
+}

lib/form/datetimeselector.php

@@ -0,0 +1,339 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Group of date and time input element
+ *
+ * Contains class for a group of elements used to input a date and time.
+ *
+ * @package   core_form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+require_once($CFG->libdir . '/form/group.php');
+require_once($CFG->libdir . '/formslib.php');
+
+/**
+ * Element used to input a date and time.
+ *
+ * Class for a group of elements used to input a date and time.
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_date_time_selector extends MoodleQuickForm_group {
+
+    /**
+     * Options for the element.
+     *
+     * startyear => int start of range of years that can be selected
+     * stopyear => int last year that can be selected
+     * defaulttime => default time value if the field is currently not set
+     * timezone => int|float|string (optional) timezone modifier used for edge case only.
+     *      If not specified, then date is caclulated based on current user timezone.
+     *      Note: dst will be calculated for string timezones only
+     *      {@link https://moodledev.io/docs/apis/subsystems/time#timezone}
+     * step => step to increment minutes by
+     * optional => if true, show a checkbox beside the date to turn it on (or off)
+     * @var array
+     */
+    protected $_options = array();
+
+    /**
+     * @var array These complement separators, they are appended to the resultant HTML.
+     */
+    protected $_wrap = array('', '');
+
+    /**
+     * @var null|bool Keeps track of whether the date selector was initialised using createElement
+     *                or addElement. If true, createElement was used signifying the element has been
+     *                added to a group - see MDL-39187.
+     */
+    protected $_usedcreateelement = true;
+
+    /**
+     * Class constructor
+     *
+     * @param string $elementName Element's name
+     * @param mixed $elementLabel Label(s) for an element
+     * @param array $options Options to control the element's display
+     * @param mixed $attributes Either a typical HTML attribute string or an associative array
+     */
+    public function __construct($elementName = null, $elementLabel = null, $options = array(), $attributes = null) {
+        // Get the calendar type used - see MDL-18375.
+        $calendartype = \core_calendar\type_factory::get_calendar_instance();
+        $this->_options = array('startyear' => $calendartype->get_min_year(), 'stopyear' => $calendartype->get_max_year(),
+            'defaulttime' => 0, 'timezone' => 99, 'step' => 1, 'optional' => false);
+
+        // TODO MDL-52313 Replace with the call to parent::__construct().
+        HTML_QuickForm_element::__construct($elementName, $elementLabel, $attributes);
+        $this->_persistantFreeze = true;
+        $this->_appendName = true;
+        $this->_type = 'date_time_selector';
+        // set the options, do not bother setting bogus ones
+        if (is_array($options)) {
+            foreach ($options as $name => $value) {
+                if (isset($this->_options[$name])) {
+                    if (is_array($value) && is_array($this->_options[$name])) {
+                        $this->_options[$name] = @array_merge($this->_options[$name], $value);
+                    } else {
+                        $this->_options[$name] = $value;
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_date_time_selector($elementName = null, $elementLabel = null, $options = array(), $attributes = null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $options, $attributes);
+    }
+
+    /**
+     * This will create date group element constisting of day, month and year.
+     *
+     * @access private
+     */
+    function _createElements() {
+        global $OUTPUT;
+
+        // Get the calendar type used - see MDL-18375.
+        $calendartype = \core_calendar\type_factory::get_calendar_instance();
+
+        for ($i = 0; $i <= 23; $i++) {
+            $hours[$i] = sprintf("%02d", $i);
+        }
+        for ($i = 0; $i < 60; $i += $this->_options['step']) {
+            $minutes[$i] = sprintf("%02d", $i);
+        }
+
+        $this->_elements = array();
+        // If optional we add a checkbox which the user can use to turn if on.
+        if ($this->_options['optional']) {
+            $this->_elements[] = $this->createFormElement('checkbox', 'enabled', null,
+                get_string('enable'), $this->getAttributesForFormElement(), true);
+        }
+        $dateformat = $calendartype->get_date_order($this->_options['startyear'], $this->_options['stopyear']);
+        if (right_to_left()) {   // Display time to the right of date, in RTL mode.
+            $this->_elements[] = $this->createFormElement('select', 'minute', get_string('minute', 'form'),
+                $minutes, $this->getAttributesForFormElement(), true);
+            $this->_elements[] = $this->createFormElement('select', 'hour', get_string('hour', 'form'),
+                $hours, $this->getAttributesForFormElement(), true);
+            // Reverse date element (Should be: Day, Month, Year), in RTL mode.
+            $dateformat = array_reverse($dateformat);
+        }
+        foreach ($dateformat as $key => $date) {
+            // E_STRICT creating elements without forms is nasty because it internally uses $this
+            $this->_elements[] = $this->createFormElement('select', $key, get_string($key, 'form'), $date,
+                $this->getAttributesForFormElement(), true);
+        }
+        if (!right_to_left()) {   // Display time to the left of date, in LTR mode.
+            $this->_elements[] = $this->createFormElement('select', 'hour', get_string('hour', 'form'), $hours,
+                $this->getAttributesForFormElement(), true);
+            $this->_elements[] = $this->createFormElement('select', 'minute', get_string('minute', 'form'), $minutes,
+                $this->getAttributesForFormElement(), true);
+        }
+        // The YUI2 calendar only supports the gregorian calendar type so only display the calendar image if this is being used.
+        if ($calendartype->get_name() === 'gregorian') {
+            $image = $OUTPUT->pix_icon('i/calendar', get_string('calendar', 'calendar'), 'moodle');
+            $this->_elements[] = $this->createFormElement('link', 'calendar',
+                    null, '#', $image);
+        }
+        foreach ($this->_elements as $element){
+            if (method_exists($element, 'setHiddenLabel')){
+                $element->setHiddenLabel(true);
+            }
+        }
+
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return bool
+     */
+    function onQuickFormEvent($event, $arg, &$caller) {
+        $this->setMoodleForm($caller);
+        switch ($event) {
+            case 'updateValue':
+                // Constant values override both default and submitted ones
+                // default values are overriden by submitted.
+                $value = $this->_findValue($caller->_constantValues);
+                if (null === $value) {
+                    // If no boxes were checked, then there is no value in the array
+                    // yet we don't want to display default value in this case.
+                    if ($caller->isSubmitted() && !$caller->is_new_repeat($this->getName())) {
+                        $value = $this->_findValue($caller->_submitValues);
+                    } else {
+                        $value = $this->_findValue($caller->_defaultValues);
+                    }
+                }
+                $requestvalue=$value;
+                if ($value == 0 || $value === '') {
+                    $value = $this->_options['defaulttime'];
+                    if (!$value) {
+                        $value = time();
+                    }
+                }
+                if (!is_array($value)) {
+                    $calendartype = \core_calendar\type_factory::get_calendar_instance();
+                    $currentdate = $calendartype->timestamp_to_date_array($value, $this->_options['timezone']);
+                    // Round minutes to the previous multiple of step.
+                    $currentdate['minutes'] -= $currentdate['minutes'] % $this->_options['step'];
+                    $value = array(
+                        'minute' => $currentdate['minutes'],
+                        'hour' => $currentdate['hours'],
+                        'day' => $currentdate['mday'],
+                        'month' => $currentdate['mon'],
+                        'year' => $currentdate['year']);
+                    // If optional, default to off, unless a date was provided.
+                    if ($this->_options['optional']) {
+                        $value['enabled'] = $requestvalue != 0;
+                    }
+                } else {
+                    $value['enabled'] = isset($value['enabled']);
+                }
+                if (null !== $value) {
+                    $this->setValue($value);
+                }
+                break;
+            case 'createElement':
+                if (isset($arg[2]['optional']) && $arg[2]['optional']) {
+                    // When using the function addElement, rather than createElement, we still
+                    // enter this case, making this check necessary.
+                    if ($this->_usedcreateelement) {
+                        $caller->disabledIf($arg[0] . '[day]', $arg[0] . '[enabled]');
+                        $caller->disabledIf($arg[0] . '[month]', $arg[0] . '[enabled]');
+                        $caller->disabledIf($arg[0] . '[year]', $arg[0] . '[enabled]');
+                        $caller->disabledIf($arg[0] . '[hour]', $arg[0] . '[enabled]');
+                        $caller->disabledIf($arg[0] . '[minute]', $arg[0] . '[enabled]');
+                    } else {
+                        $caller->disabledIf($arg[0], $arg[0] . '[enabled]');
+                    }
+                }
+                return parent::onQuickFormEvent($event, $arg, $caller);
+                break;
+            case 'addElement':
+                $this->_usedcreateelement = false;
+                return parent::onQuickFormEvent($event, $arg, $caller);
+                break;
+            default:
+                return parent::onQuickFormEvent($event, $arg, $caller);
+        }
+    }
+
+    /**
+     * Returns HTML for advchecbox form element.
+     *
+     * @return string
+     */
+    function toHtml() {
+        include_once('HTML/QuickForm/Renderer/Default.php');
+        $renderer = new HTML_QuickForm_Renderer_Default();
+        $renderer->setElementTemplate('{element}');
+        parent::accept($renderer);
+
+        $html = $this->_wrap[0];
+        if ($this->_usedcreateelement) {
+            $html .= html_writer::tag('span', $renderer->toHtml(), array('class' => 'fdate_time_selector'));
+        } else {
+            $html .= $renderer->toHtml();
+        }
+        $html .= $this->_wrap[1];
+
+        return $html;
+    }
+
+    /**
+     * Accepts a renderer
+     *
+     * @param HTML_QuickForm_Renderer $renderer An HTML_QuickForm_Renderer object
+     * @param bool $required Whether a group is required
+     * @param string $error An error message associated with a group
+     */
+    function accept(&$renderer, $required = false, $error = null) {
+        form_init_date_js();
+        $renderer->renderElement($this, $required, $error);
+    }
+
+    /**
+     * Export for template
+     *
+     * @param renderer_base $output
+     * @return array|stdClass
+     */
+    public function export_for_template(renderer_base $output) {
+        form_init_date_js();
+        return parent::export_for_template($output);
+    }
+
+    /**
+     * Output a timestamp. Give it the name of the group.
+     *
+     * @param array $submitValues values submitted.
+     * @param bool $assoc specifies if returned array is associative
+     * @return array
+     */
+    function exportValue(&$submitValues, $assoc = false) {
+        $valuearray = array();
+        foreach ($this->_elements as $element){
+            $thisexport = $element->exportValue($submitValues[$this->getName()], true);
+            if ($thisexport!=null){
+                $valuearray += $thisexport;
+            }
+        }
+        if (count($valuearray)){
+            if($this->_options['optional']) {
+                // If checkbox is on, the value is zero, so go no further
+                if(empty($valuearray['enabled'])) {
+                    return $this->_prepareValue(0, $assoc);
+                }
+            }
+            // Get the calendar type used - see MDL-18375.
+            $calendartype = \core_calendar\type_factory::get_calendar_instance();
+            $gregoriandate = $calendartype->convert_to_gregorian($valuearray['year'],
+                                                                 $valuearray['month'],
+                                                                 $valuearray['day'],
+                                                                 $valuearray['hour'],
+                                                                 $valuearray['minute']);
+            $value = make_timestamp($gregoriandate['year'],
+                                                      $gregoriandate['month'],
+                                                      $gregoriandate['day'],
+                                                      $gregoriandate['hour'],
+                                                      $gregoriandate['minute'],
+                                                      0,
+                                                      $this->_options['timezone'],
+                                                      true);
+
+            return $this->_prepareValue($value, $assoc);
+        } else {
+            return null;
+        }
+    }
+}

lib/form/defaultcustom.php

@@ -0,0 +1,279 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Creates an element with a dropdown Default/Custom and an input for the value (text or date_selector)
+ *
+ * @package   core_form
+ * @copyright 2017 Marina Glancy
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+require_once($CFG->libdir . '/form/group.php');
+require_once($CFG->libdir . '/formslib.php');
+
+/**
+ * Creates an element with a dropdown Default/Custom and an input for the value (text or date_selector)
+ *
+ * @package   core_form
+ * @copyright 2017 Marina Glancy
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_defaultcustom extends MoodleQuickForm_group {
+
+    /**
+     * @var array These complement separators, they are appended to the resultant HTML.
+     */
+    protected $_wrap = array('', '');
+
+    /**
+     * @var null|bool Keeps track of whether the date selector was initialised using createElement
+     *                or addElement. If true, createElement was used signifying the element has been
+     *                added to a group - see MDL-39187.
+     */
+    protected $_usedcreateelement = true;
+
+    /** @var array */
+    protected $_options;
+
+    /**
+     * Constructor
+     *
+     * @param string $elementname Element's name
+     * @param mixed $elementlabel Label(s) for an element
+     * @param array $options Options to control the element's display
+     * @param mixed $attributes Either a typical HTML attribute string or an associative array
+     */
+    public function __construct($elementname = null, $elementlabel = null, $options = array(), $attributes = null) {
+        parent::__construct($elementname, $elementlabel);
+        $this->setAttributes($attributes);
+
+        $this->_appendName = true;
+        $this->_type = 'defaultcustom';
+
+        $calendartype = \core_calendar\type_factory::get_calendar_instance();
+        $this->_options = [
+            'type' => 'text', // Type of the element. Supported are 'text' and 'date_selector'.
+            'defaultvalue' => null, // Value to be used when not overridden.
+            'customvalue' => null, // Value to be used when overwriting.
+            'customlabel' => get_string('custom', 'form'), // Label for 'customize' checkbox
+            // Other options are the same as the ones that can be passed to 'date_selector' element.
+            'timezone' => 99,
+            'startyear' => $calendartype->get_min_year(),
+            'stopyear' => $calendartype->get_max_year(),
+            'defaulttime' => 0,
+            'step' => 1,
+            'optional' => false,
+        ];
+
+        if (is_array($options)) {
+            foreach ($options as $name => $value) {
+                if (array_key_exists($name, $this->_options)) {
+                    if ($name === 'type' && !in_array($value, ['text', 'date_selector', 'date_time_selector'])) {
+                        throw new coding_exception('Only text, date_selector, and date_time_selector elements are supported in ' . $this->_type);
+                    }
+                    if ($name === 'optional' && $value) {
+                        throw new coding_exception('Date selector can not be optional in ' . $this->_type);
+                    }
+                    $this->_options[$name] = $value;
+                }
+            }
+        }
+    }
+
+    /**
+     * Converts timestamp to the day/month/year array in the current calendar format
+     * @param int $value
+     * @return array
+     */
+    protected function timestamp_to_date_array($value) {
+        $calendartype = \core_calendar\type_factory::get_calendar_instance();
+        $currentdate = $calendartype->timestamp_to_date_array((int)$value, $this->_options['timezone']);
+        return array(
+            'minute' => $currentdate['minutes'],
+            'hour' => $currentdate['hours'],
+            'day' => $currentdate['mday'],
+            'month' => $currentdate['mon'],
+            'year' => $currentdate['year']);
+    }
+
+    /**
+     * Should this element have default/custom switch?
+     *
+     * @return bool
+     */
+    protected function has_customize_switch() {
+        return $this->_options['defaultvalue'] !== null;
+    }
+
+    /**
+     * This will create all elements in the group
+     */
+    public function _createElements() {
+        if (!$this->has_customize_switch()) {
+            $element = $this->createFormElement('hidden', 'customize', 1);
+        } else {
+            $element = $this->createFormElement('advcheckbox', 'customize', '', $this->_options['customlabel']);
+        }
+        $this->_elements[] = $element;
+
+        if ($this->_options['type'] === 'text') {
+            $element = $this->createFormElement($this->_options['type'], 'value',
+                get_string('newvaluefor', 'form', $this->getLabel()), $this->getAttributes());
+            $element->setHiddenLabel(true);
+        } else if ($this->_options['type'] === 'date_selector') {
+            $element = $this->createFormElement($this->_options['type'], 'value', '', $this->_options,
+                $this->getAttributes());
+        } else if ($this->_options['type'] === 'date_time_selector') {
+            $element = $this->createFormElement($this->_options['type'], 'value', '', $this->_options,
+                $this->getAttributes());
+        }
+        $this->_elements[] = $element;
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return bool
+     */
+    public function onQuickFormEvent($event, $arg, &$caller) {
+        $this->setMoodleForm($caller);
+        switch ($event) {
+            case 'updateValue':
+                // Constant values override both default and submitted ones
+                // default values are overriden by submitted.
+                $value = $this->_findValue($caller->_constantValues);
+                if (null === $value) {
+                    // If no boxes were checked, then there is no value in the array
+                    // yet we don't want to display default value in this case.
+                    if ($caller->isSubmitted()) {
+                        $value = $this->_findValue($caller->_submitValues);
+                    } else {
+                        $value = $this->_findValue($caller->_defaultValues);
+                    }
+                }
+                if (!is_array($value)) {
+                    $customize = ($value !== false || !$this->has_customize_switch());
+                    if ($this->_options['type'] === 'text') {
+                        $elementvalue = $customize ? $value : $this->_options['defaultvalue'];
+                    } else {
+                        $elementvalue = $this->timestamp_to_date_array($customize ? $value : $this->_options['defaultvalue']);
+                    }
+                    $value = [
+                        'customize' => $customize,
+                        'value' => $elementvalue
+                    ];
+                }
+                $this->setValue($value);
+                break;
+            case 'createElement':
+                $rv = parent::onQuickFormEvent($event, $arg, $caller);
+                if ($this->has_customize_switch()) {
+                    if ($this->_options['type'] === 'text') {
+                        $caller->disabledIf($arg[0] . '[value]', $arg[0] . '[customize]', 'notchecked');
+                    } else if ($this->_options['type'] === 'date_selector') {
+                        $caller->disabledIf($arg[0] . '[value][day]', $arg[0] . '[customize]', 'notchecked');
+                        $caller->disabledIf($arg[0] . '[value][month]', $arg[0] . '[customize]', 'notchecked');
+                        $caller->disabledIf($arg[0] . '[value][year]', $arg[0] . '[customize]', 'notchecked');
+                    } else {
+                        // Date / Time selector.
+                        $caller->disabledIf($arg[0] . '[value][day]', $arg[0] . '[customize]', 'notchecked');
+                        $caller->disabledIf($arg[0] . '[value][month]', $arg[0] . '[customize]', 'notchecked');
+                        $caller->disabledIf($arg[0] . '[value][year]', $arg[0] . '[customize]', 'notchecked');
+                        $caller->disabledIf($arg[0] . '[value][hour]', $arg[0] . '[customize]', 'notchecked');
+                        $caller->disabledIf($arg[0] . '[value][minute]', $arg[0] . '[customize]', 'notchecked');
+                    }
+                }
+                return $rv;
+            case 'addElement':
+                $this->_usedcreateelement = false;
+                return parent::onQuickFormEvent($event, $arg, $caller);
+                break;
+            default:
+                return parent::onQuickFormEvent($event, $arg, $caller);
+        }
+    }
+
+    public function freeze() {
+        parent::freeze();
+        $this->setPersistantFreeze(true);
+    }
+
+    public function toHtml() {
+        include_once('HTML/QuickForm/Renderer/Default.php');
+        $renderer = new HTML_QuickForm_Renderer_Default();
+        $renderer->setElementTemplate('{element}');
+        parent::accept($renderer);
+
+        $html = $this->_wrap[0];
+        if ($this->_usedcreateelement) {
+            $html .= html_writer::tag('span', $renderer->toHtml(), array('class' => 'fdefaultcustom'));
+        } else {
+            $html .= $renderer->toHtml();
+        }
+        $html .= $this->_wrap[1];
+
+        return $html;
+    }
+
+    public function accept(&$renderer, $required = false, $error = null) {
+        global $PAGE;
+
+        if (!$this->_flagFrozen && $this->has_customize_switch()) {
+            // Add JS to the default/custom switch.
+            $firstelement = reset($this->_elements);
+            $defaultvalue = $this->_options['defaultvalue'];
+            $customvalue = $this->_options['customvalue'];
+            if ($this->_options['type'] === 'date_selector' || $this->_options['type'] === 'date_time_selector') {
+                $defaultvalue = $this->timestamp_to_date_array($defaultvalue);
+                $customvalue = $this->timestamp_to_date_array($customvalue);
+            }
+            $firstelement->updateAttributes(['data-defaultcustom' => 'true',
+                'data-type' => $this->_options['type'],
+                'data-defaultvalue' => json_encode($defaultvalue),
+                'data-customvalue' => json_encode($customvalue)]);
+            $PAGE->requires->js_amd_inline("require(['core_form/defaultcustom'], function() {});");
+        }
+
+        $renderer->renderElement($this, $required, $error);
+    }
+
+    /**
+     * Output a value. Give it the name of the group. In case of "default" return false.
+     *
+     * @param array $submitvalues values submitted.
+     * @param bool $assoc specifies if returned array is associative
+     * @return array
+     */
+    public function exportValue(&$submitvalues, $assoc = false) {
+        $valuearray = array();
+        foreach ($this->_elements as $element) {
+            $thisexport = $element->exportValue($submitvalues[$this->getName()], true);
+            if ($thisexport != null) {
+                $valuearray += $thisexport;
+            }
+        }
+        if (empty($valuearray['customize'])) {
+            return $this->_prepareValue(false, $assoc);
+        }
+        return array_key_exists('value', $valuearray) ? $this->_prepareValue($valuearray['value'], $assoc) : [];
+    }
+}

lib/form/duration.php

@@ -0,0 +1,303 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Duration form element
+ *
+ * Contains class to create length of time for element.
+ *
+ * @package   core_form
+ * @copyright 2009 Tim Hunt
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+require_once($CFG->libdir . '/form/group.php');
+require_once($CFG->libdir . '/formslib.php');
+require_once($CFG->libdir . '/form/text.php');
+
+/**
+ * Duration element
+ *
+ * HTML class for a length of time. For example, 30 minutes of 4 days. The
+ * values returned to PHP is the duration in seconds (an int rounded to the nearest second).
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2009 Tim Hunt
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_duration extends MoodleQuickForm_group {
+    /**
+     * Control the field names for form elements
+     * optional => if true, show a checkbox beside the element to turn it on (or off)
+     * defaultunit => which unit is default when the form is blank (default Minutes).
+     * @var array
+     */
+    protected $_options = ['optional' => false, 'defaultunit' => MINSECS];
+
+    /** @var array associative array of time units (days, hours, minutes, seconds) */
+    private $_units = null;
+
+   /**
+    * constructor
+    *
+    * @param ?string $elementName Element's name
+    * @param mixed $elementLabel Label(s) for an element
+    * @param array $options Options to control the element's display. Recognised values are
+    *      'optional' => true/false - whether to display an 'enabled' checkbox next to the element.
+    *      'defaultunit' => 1|MINSECS|HOURSECS|DAYSECS|WEEKSECS - the default unit to display when
+    *              the time is blank. If not specified, minutes is used.
+    *      'units' => array containing some or all of 1, MINSECS, HOURSECS, DAYSECS and WEEKSECS
+    *              which unit choices to offer.
+    * @param mixed $attributes Either a typical HTML attribute string or an associative array
+    */
+    public function __construct($elementName = null, $elementLabel = null,
+            $options = [], $attributes = null) {
+        parent::__construct($elementName, $elementLabel, $attributes);
+        $this->_persistantFreeze = true;
+        $this->_appendName = true;
+        $this->_type = 'duration';
+
+        // Set the options, do not bother setting bogus ones
+        if (!is_array($options)) {
+            $options = [];
+        }
+        $this->_options['optional'] = !empty($options['optional']);
+        if (isset($options['defaultunit'])) {
+            if (!array_key_exists($options['defaultunit'], $this->get_units())) {
+                throw new coding_exception($options['defaultunit'] .
+                        ' is not a recognised unit in MoodleQuickForm_duration.');
+            }
+            $this->_options['defaultunit'] = $options['defaultunit'];
+        }
+        if (isset($options['units'])) {
+            if (!is_array($options['units'])) {
+                throw new coding_exception(
+                        'When creating a duration form field, units option must be an array.');
+            }
+            // Validate and register requested units.
+            $availableunits = $this->get_units();
+            $displayunits = [];
+            foreach ($options['units'] as $requestedunit) {
+                if (!isset($availableunits[$requestedunit])) {
+                    throw new coding_exception($requestedunit .
+                            ' is not a recognised unit in MoodleQuickForm_duration.');
+                }
+                $displayunits[$requestedunit] = $availableunits[$requestedunit];
+            }
+            krsort($displayunits, SORT_NUMERIC);
+            $this->_options['units'] = $displayunits;
+        }
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_duration($elementName = null, $elementLabel = null,
+            $options = [], $attributes = null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $options, $attributes);
+    }
+
+    /**
+     * Returns time associative array of unit length.
+     *
+     * @return array unit length in seconds => string unit name.
+     */
+    public function get_units() {
+        if (is_null($this->_units)) {
+            $this->_units = [
+                WEEKSECS => get_string('weeks'),
+                DAYSECS => get_string('days'),
+                HOURSECS => get_string('hours'),
+                MINSECS => get_string('minutes'),
+                1 => get_string('seconds'),
+            ];
+        }
+        return $this->_units;
+    }
+
+    /**
+     * Get the units to be used for this field.
+     *
+     * The ones specified in the options passed to the constructor, or all by default.
+     *
+     * @return array number of seconds => lang string.
+     */
+    protected function get_units_used() {
+        if (!empty($this->_options['units'])) {
+            return $this->_options['units'];
+        } else {
+            return $this->get_units();
+        }
+    }
+
+    /**
+     * Converts seconds to the best possible time unit. for example
+     * 1800 -> [30, MINSECS] = 30 minutes.
+     *
+     * @param int $seconds an amout of time in seconds.
+     * @return array associative array ($number => $unit)
+     */
+    public function seconds_to_unit($seconds) {
+        if (empty($seconds)) {
+            return [0, $this->_options['defaultunit']];
+        }
+        foreach ($this->get_units_used() as $unit => $notused) {
+            if (fmod($seconds, $unit) == 0) {
+                return [$seconds / $unit, $unit];
+            }
+        }
+        return [$seconds, 1];
+    }
+
+    /**
+     * Override of standard quickforms method to create this element.
+     */
+    function _createElements() {
+        $attributes = $this->getAttributesForFormElement();
+        if (!isset($attributes['size'])) {
+            $attributes['size'] = 3;
+        }
+        $this->_elements = [];
+        // E_STRICT creating elements without forms is nasty because it internally uses $this
+        $number = $this->createFormElement('text', 'number',
+                get_string('time', 'form'), $attributes, true);
+        $number->set_force_ltr(true);
+        $this->_elements[] = $number;
+        unset($attributes['size']);
+        $this->_elements[] = $this->createFormElement('select', 'timeunit',
+                get_string('timeunit', 'form'), $this->get_units_used(), $attributes, true);
+        // If optional we add a checkbox which the user can use to turn if on
+        if($this->_options['optional']) {
+            $this->_elements[] = $this->createFormElement('checkbox', 'enabled', null,
+                    get_string('enable'), $attributes, true);
+        }
+        foreach ($this->_elements as $element){
+            if (method_exists($element, 'setHiddenLabel')){
+                $element->setHiddenLabel(true);
+            }
+        }
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param MoodleQuickForm $caller calling object
+     * @return bool
+     */
+    function onQuickFormEvent($event, $arg, &$caller) {
+        $this->setMoodleForm($caller);
+        switch ($event) {
+            case 'updateValue':
+                // constant values override both default and submitted ones
+                // default values are overriden by submitted
+                $value = $this->_findValue($caller->_constantValues);
+                if (null === $value) {
+                    // if no boxes were checked, then there is no value in the array
+                    // yet we don't want to display default value in this case
+                    if ($caller->isSubmitted() && !$caller->is_new_repeat($this->getName())) {
+                        $value = $this->_findValue($caller->_submitValues);
+                    } else {
+                        $value = $this->_findValue($caller->_defaultValues);
+                    }
+                }
+                if (!is_array($value)) {
+                    list($number, $unit) = $this->seconds_to_unit($value);
+                    $value = ['number' => $number, 'timeunit' => $unit];
+                    // If optional, default to off, unless a date was provided
+                    if ($this->_options['optional']) {
+                        $value['enabled'] = $number != 0;
+                    }
+                } else {
+                    $value['enabled'] = isset($value['enabled']);
+                }
+                if (null !== $value){
+                    $this->setValue($value);
+                }
+                break;
+
+            case 'createElement':
+                if (!empty($arg[2]['optional'])) {
+                    $caller->disabledIf($arg[0], $arg[0] . '[enabled]');
+                }
+                $caller->setType($arg[0] . '[number]', PARAM_FLOAT);
+                return parent::onQuickFormEvent($event, $arg, $caller);
+
+            default:
+                return parent::onQuickFormEvent($event, $arg, $caller);
+        }
+    }
+
+    /**
+     * Returns HTML for advchecbox form element.
+     *
+     * @return string
+     */
+    function toHtml() {
+        include_once('HTML/QuickForm/Renderer/Default.php');
+        $renderer = new HTML_QuickForm_Renderer_Default();
+        $renderer->setElementTemplate('{element}');
+        parent::accept($renderer);
+        return $renderer->toHtml();
+    }
+
+    /**
+     * Accepts a renderer
+     *
+     * @param HTML_QuickForm_Renderer $renderer An HTML_QuickForm_Renderer object
+     * @param bool $required Whether a group is required
+     * @param ?string $error An error message associated with a group
+     */
+    function accept(&$renderer, $required = false, $error = null) {
+        $renderer->renderElement($this, $required, $error);
+    }
+
+    /**
+     * Output a timestamp. Give it the name of the group.
+     * Override of standard quickforms method.
+     *
+     * @param  array $submitValues
+     * @param  bool  $assoc  whether to return the value as associative array
+     * @return array field name => value. The value is the time interval in seconds.
+     */
+    function exportValue(&$submitValues, $assoc = false) {
+        // Get the values from all the child elements.
+        $valuearray = [];
+        foreach ($this->_elements as $element) {
+            $thisexport = $element->exportValue($submitValues[$this->getName()], true);
+            if (!is_null($thisexport)) {
+                $valuearray += $thisexport;
+            }
+        }
+
+        // Convert the value to an integer number of seconds.
+        if (empty($valuearray)) {
+            return null;
+        }
+        if ($this->_options['optional'] && empty($valuearray['enabled'])) {
+            return $this->_prepareValue(0, $assoc);
+        }
+        return $this->_prepareValue(
+                (int) round($valuearray['number'] * $valuearray['timeunit']), $assoc);
+    }
+}

lib/form/editor.php

@@ -0,0 +1,522 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Editor input element
+ *
+ * Contains class to create preffered editor form element
+ *
+ * @package   core_form
+ * @copyright 2009 Petr Skoda {@link http://skodak.org}
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+
+require_once('HTML/QuickForm/element.php');
+require_once($CFG->dirroot.'/lib/filelib.php');
+require_once($CFG->dirroot.'/repository/lib.php');
+require_once('templatable_form_element.php');
+
+/**
+ * Editor element
+ *
+ * It creates preffered editor (textbox/Tiny) form element for the format (Text/HTML) selected.
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2009 Petr Skoda {@link http://skodak.org}
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @todo      MDL-29421 element Freezing
+ * @todo      MDL-29426 ajax format conversion
+ */
+class MoodleQuickForm_editor extends HTML_QuickForm_element implements templatable {
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+
+    /** @var string html for help button, if empty then no help will icon will be dispalyed. */
+    public $_helpbutton = '';
+
+    /** @var string defines the type of editor */
+    public $_type       = 'editor';
+
+    /** @var array options provided to initalize filepicker */
+    protected $_options = array('subdirs' => 0, 'maxbytes' => 0, 'maxfiles' => 0, 'changeformat' => 0,
+            'areamaxbytes' => FILE_AREA_MAX_BYTES_UNLIMITED, 'context' => null, 'noclean' => 0, 'trusttext' => 0,
+            'return_types' => 15, 'enable_filemanagement' => true, 'removeorphaneddrafts' => false, 'autosave' => true);
+    // 15 is $_options['return_types'] = FILE_INTERNAL | FILE_EXTERNAL | FILE_REFERENCE | FILE_CONTROLLED_LINK.
+
+    /** @var array values for editor */
+    protected $_values     = array('text'=>null, 'format'=>null, 'itemid'=>null);
+
+    /** @var bool if true label will be hidden */
+    protected $_hiddenLabel = false;
+
+    /**
+     * Constructor
+     *
+     * @param string $elementName (optional) name of the editor
+     * @param string $elementLabel (optional) editor label
+     * @param array $attributes (optional) Either a typical HTML attribute string
+     *              or an associative array
+     * @param array $options set of options to initalize filepicker
+     */
+    public function __construct($elementName=null, $elementLabel=null, $attributes=null, $options=null) {
+        global $CFG, $PAGE;
+
+        $options = (array)$options;
+        foreach ($options as $name=>$value) {
+            if (array_key_exists($name, $this->_options)) {
+                $this->_options[$name] = $value;
+            }
+        }
+        if (!empty($options['maxbytes'])) {
+            $this->_options['maxbytes'] = get_max_upload_file_size($CFG->maxbytes, $options['maxbytes']);
+        }
+        if (!$this->_options['context']) {
+            // trying to set context to the current page context to make legacy files show in filepicker (e.g. forum post)
+            if (!empty($PAGE->context->id)) {
+                $this->_options['context'] = $PAGE->context;
+            } else {
+                $this->_options['context'] = context_system::instance();
+            }
+        }
+        $this->_options['trusted'] = trusttext_trusted($this->_options['context']);
+        parent::__construct($elementName, $elementLabel, $attributes);
+
+        // Note: for some reason the code using this setting does not like bools.
+        $this->_options['subdirs'] = (int)($this->_options['subdirs'] == 1);
+
+        editors_head_setup();
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_editor($elementName=null, $elementLabel=null, $attributes=null, $options=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $attributes, $options);
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return bool
+     */
+    function onQuickFormEvent($event, $arg, &$caller)
+    {
+        switch ($event) {
+            case 'createElement':
+                $caller->setType($arg[0] . '[format]', PARAM_ALPHANUM);
+                $caller->setType($arg[0] . '[itemid]', PARAM_INT);
+                break;
+        }
+        return parent::onQuickFormEvent($event, $arg, $caller);
+    }
+
+    /**
+     * Sets name of editor
+     *
+     * @param string $name name of the editor
+     */
+    function setName($name) {
+        $this->updateAttributes(array('name'=>$name));
+    }
+
+    /**
+     * Returns name of element
+     *
+     * @return string
+     */
+    function getName() {
+        return $this->getAttribute('name');
+    }
+
+    /**
+     * Updates editor values, if part of $_values
+     *
+     * @param array $values associative array of values to set
+     */
+    function setValue($values) {
+        $values = (array)$values;
+        foreach ($values as $name=>$value) {
+            if (array_key_exists($name, $this->_values)) {
+                $this->_values[$name] = $value;
+            }
+        }
+    }
+
+    /**
+     * Returns editor values
+     *
+     * @return array
+     */
+    function getValue() {
+        return $this->_values;
+    }
+
+    /**
+     * Returns maximum file size which can be uploaded
+     *
+     * @return int
+     */
+    function getMaxbytes() {
+        return $this->_options['maxbytes'];
+    }
+
+    /**
+     * Sets maximum file size which can be uploaded
+     *
+     * @param int $maxbytes file size
+     */
+    function setMaxbytes($maxbytes) {
+        global $CFG;
+        $this->_options['maxbytes'] = get_max_upload_file_size($CFG->maxbytes, $maxbytes);
+    }
+
+     /**
+     * Returns the maximum size of the area.
+     *
+     * @return int
+     */
+    function getAreamaxbytes() {
+        return $this->_options['areamaxbytes'];
+    }
+
+    /**
+     * Sets the maximum size of the area.
+     *
+     * @param int $areamaxbytes size limit
+     */
+    function setAreamaxbytes($areamaxbytes) {
+        $this->_options['areamaxbytes'] = $areamaxbytes;
+    }
+
+    /**
+     * Returns maximum number of files which can be uploaded
+     *
+     * @return int
+     */
+    function getMaxfiles() {
+        return $this->_options['maxfiles'];
+    }
+
+    /**
+     * Sets maximum number of files which can be uploaded.
+     *
+     * @param int $num number of files
+     */
+    function setMaxfiles($num) {
+        $this->_options['maxfiles'] = $num;
+    }
+
+    /**
+     * Returns true if subdirectoy can be created, else false
+     *
+     * @return bool
+     */
+    function getSubdirs() {
+        return $this->_options['subdirs'];
+    }
+
+    /**
+     * Set option to create sub directory, while uploading  file
+     *
+     * @param bool $allow true if sub directory can be created.
+     */
+    function setSubdirs($allow) {
+        $this->_options['subdirs'] = (int)($allow == 1);
+    }
+
+    /**
+     * Returns editor text content
+     *
+     * @return string Text content
+     */
+    public function get_text(): string {
+        return $this->_values['text'];
+    }
+
+    /**
+     * Returns editor format
+     *
+     * @return int.
+     */
+    function getFormat() {
+        return $this->_values['format'];
+    }
+
+    /**
+     * Checks if editor used is a required field
+     *
+     * @return bool true if required field.
+     */
+    function isRequired() {
+        return (isset($this->_options['required']) && $this->_options['required']);
+    }
+
+    /**
+     * @deprecated since Moodle 2.0
+     */
+    function setHelpButton($_helpbuttonargs, $function='_helpbutton') {
+        throw new coding_exception('setHelpButton() can not be used any more, please see MoodleQuickForm::addHelpButton().');
+    }
+
+    /**
+     * Returns html for help button.
+     *
+     * @return string html for help button
+     */
+    function getHelpButton() {
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Returns type of editor element
+     *
+     * @return string
+     */
+    function getElementTemplateType() {
+        if ($this->_flagFrozen){
+            return 'nodisplay';
+        } else {
+            return 'default';
+        }
+    }
+
+    /**
+     * Returns HTML for editor form element.
+     *
+     * @return string
+     */
+    function toHtml() {
+        global $CFG, $PAGE, $OUTPUT;
+        require_once($CFG->dirroot.'/repository/lib.php');
+
+        if ($this->_flagFrozen) {
+            return $this->getFrozenHtml();
+        }
+
+        $ctx = $this->_options['context'];
+
+        $id           = $this->_attributes['id'];
+        $elname       = $this->_attributes['name'];
+
+        $subdirs      = $this->_options['subdirs'];
+        $maxbytes     = $this->_options['maxbytes'];
+        $areamaxbytes = $this->_options['areamaxbytes'];
+        $maxfiles     = $this->_options['maxfiles'];
+        $changeformat = $this->_options['changeformat']; // TO DO: implement as ajax calls
+
+        $text         = $this->_values['text'];
+        $format       = $this->_values['format'];
+        $draftitemid  = $this->_values['itemid'];
+
+        // security - never ever allow guest/not logged in user to upload anything
+        if (isguestuser() or !isloggedin()) {
+            $maxfiles = 0;
+        }
+
+        $str = $this->_getTabs();
+        $str .= '<div>';
+
+        $editor = editors_get_preferred_editor($format);
+        $strformats = format_text_menu();
+        $formats =  $editor->get_supported_formats();
+        foreach ($formats as $fid) {
+            $formats[$fid] = $strformats[$fid];
+        }
+
+        // get filepicker info
+        //
+        $fpoptions = array();
+        if ($maxfiles != 0 ) {
+            if (empty($draftitemid)) {
+                // no existing area info provided - let's use fresh new draft area
+                require_once("$CFG->libdir/filelib.php");
+                $this->setValue(array('itemid'=>file_get_unused_draft_itemid()));
+                $draftitemid = $this->_values['itemid'];
+            }
+
+            $args = new stdClass();
+            // need these three to filter repositories list
+            $args->accepted_types = array('web_image');
+            $args->return_types = $this->_options['return_types'];
+            $args->context = $ctx;
+            $args->env = 'filepicker';
+            // advimage plugin
+            $image_options = initialise_filepicker($args);
+            $image_options->context = $ctx;
+            $image_options->client_id = uniqid();
+            $image_options->maxbytes = $this->_options['maxbytes'];
+            $image_options->areamaxbytes = $this->_options['areamaxbytes'];
+            $image_options->env = 'editor';
+            $image_options->itemid = $draftitemid;
+
+            // moodlemedia plugin
+            $args->accepted_types = array('video', 'audio');
+            $media_options = initialise_filepicker($args);
+            $media_options->context = $ctx;
+            $media_options->client_id = uniqid();
+            $media_options->maxbytes  = $this->_options['maxbytes'];
+            $media_options->areamaxbytes  = $this->_options['areamaxbytes'];
+            $media_options->env = 'editor';
+            $media_options->itemid = $draftitemid;
+
+            // advlink plugin
+            $args->accepted_types = '*';
+            $link_options = initialise_filepicker($args);
+            $link_options->context = $ctx;
+            $link_options->client_id = uniqid();
+            $link_options->maxbytes  = $this->_options['maxbytes'];
+            $link_options->areamaxbytes  = $this->_options['areamaxbytes'];
+            $link_options->env = 'editor';
+            $link_options->itemid = $draftitemid;
+
+            $args->accepted_types = array('.vtt');
+            $subtitle_options = initialise_filepicker($args);
+            $subtitle_options->context = $ctx;
+            $subtitle_options->client_id = uniqid();
+            $subtitle_options->maxbytes  = $this->_options['maxbytes'];
+            $subtitle_options->areamaxbytes  = $this->_options['areamaxbytes'];
+            $subtitle_options->env = 'editor';
+            $subtitle_options->itemid = $draftitemid;
+
+            if (has_capability('moodle/h5p:deploy', $ctx)) {
+                // Only set H5P Plugin settings if the user can deploy new H5P content.
+                // H5P plugin.
+                $args->accepted_types = array('.h5p');
+                $h5poptions = initialise_filepicker($args);
+                $h5poptions->context = $ctx;
+                $h5poptions->client_id = uniqid();
+                $h5poptions->maxbytes  = $this->_options['maxbytes'];
+                $h5poptions->areamaxbytes  = $this->_options['areamaxbytes'];
+                $h5poptions->env = 'editor';
+                $h5poptions->itemid = $draftitemid;
+                $fpoptions['h5p'] = $h5poptions;
+            }
+
+            $fpoptions['image'] = $image_options;
+            $fpoptions['media'] = $media_options;
+            $fpoptions['link'] = $link_options;
+            $fpoptions['subtitle'] = $subtitle_options;
+        }
+
+        // TODO Remove this in MDL-77334 for Moodle 4.6.
+        // If editor is required and tinymce, then set required_tinymce option to initalize tinymce validation.
+        if (($editor instanceof tinymce_texteditor)  && !is_null($this->getAttribute('onchange'))) {
+            $this->_options['required'] = true;
+        }
+
+        // print text area - TODO: add on-the-fly switching, size configuration, etc.
+        $editor->set_text($text);
+        $editor->use_editor($id, $this->_options, $fpoptions);
+
+        $rows = empty($this->_attributes['rows']) ? 15 : $this->_attributes['rows'];
+        $cols = empty($this->_attributes['cols']) ? 80 : $this->_attributes['cols'];
+
+        //Apply editor validation if required field
+        $context = [];
+        $context['rows'] = $rows;
+        $context['cols'] = $cols;
+        $context['frozen'] = $this->_flagFrozen;
+        foreach ($this->getAttributes() as $name => $value) {
+            $context[$name] = $value;
+        }
+        $context['hasformats'] = count($formats) > 1;
+        $context['formats'] = [];
+        if (($format === '' || $format === null) && count($formats)) {
+            $format = key($formats);
+        }
+        foreach ($formats as $formatvalue => $formattext) {
+            $context['formats'][] = ['value' => $formatvalue, 'text' => $formattext, 'selected' => ($formatvalue == $format)];
+        }
+        $context['id'] = $id;
+        $context['value'] = $text;
+        $context['format'] = $format;
+        $context['formatlabel'] = get_string('editorxformat', 'editor', $this->_label);
+
+        if (!is_null($this->getAttribute('onblur')) && !is_null($this->getAttribute('onchange'))) {
+            $context['changelistener'] = true;
+        }
+
+        $str .= $OUTPUT->render_from_template('core_form/editor_textarea', $context);
+
+        // during moodle installation, user area doesn't exist
+        // so we need to disable filepicker here.
+        if (!during_initial_install() && empty($CFG->adminsetuppending)) {
+            // 0 means no files, -1 unlimited
+            if ($maxfiles != 0 ) {
+                $str .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => $elname.'[itemid]',
+                        'value' => $draftitemid));
+
+                // used by non js editor only
+                $editorurl = new moodle_url("$CFG->wwwroot/repository/draftfiles_manager.php", array(
+                    'action'=>'browse',
+                    'env'=>'editor',
+                    'itemid'=>$draftitemid,
+                    'subdirs'=>$subdirs,
+                    'maxbytes'=>$maxbytes,
+                    'areamaxbytes' => $areamaxbytes,
+                    'maxfiles'=>$maxfiles,
+                    'ctx_id'=>$ctx->id,
+                    'course'=>$PAGE->course->id,
+                    'sesskey'=>sesskey(),
+                    ));
+                $str .= '<noscript>';
+                $str .= "<div><object type='text/html' data='$editorurl' height='160' width='600' style='border:1px solid #000'></object></div>";
+                $str .= '</noscript>';
+            }
+        }
+
+
+        $str .= '</div>';
+
+        return $str;
+    }
+
+    public function export_for_template(renderer_base $output) {
+        $context = $this->export_for_template_base($output);
+        $context['html'] = $this->toHtml();
+        return $context;
+    }
+
+    /**
+     * Returns the formatted value. The return from parent class is not acceptable.
+     *
+     * @return string
+     */
+    public function getFrozenHtml(): string {
+        return format_text($this->get_text(), $this->getFormat()) . $this->_getPersistantData();
+    }
+
+    /**
+     * Sets label to be hidden.
+     *
+     * @param bool $hiddenLabel Whether the label should be hidden or not.
+     * @return void
+     */
+    function setHiddenLabel($hiddenLabel) {
+        $this->_hiddenLabel = $hiddenLabel;
+    }
+}

lib/form/filemanager.php

@@ -0,0 +1,483 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * FileManager form element
+ *
+ * Contains HTML class for a filemanager form element
+ *
+ * @package   core_form
+ * @copyright 2009 Dongsheng Cai <dongsheng@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+
+require_once('HTML/QuickForm/element.php');
+require_once($CFG->dirroot.'/lib/filelib.php');
+require_once($CFG->dirroot.'/repository/lib.php');
+require_once('templatable_form_element.php');
+
+/**
+ * Filemanager form element
+ *
+ * FilemaneManager lets user to upload/manage multiple files
+ * @package   core_form
+ * @category  form
+ * @copyright 2009 Dongsheng Cai <dongsheng@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_filemanager extends HTML_QuickForm_element implements templatable {
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+
+    /** @var string html for help button, if empty then no help will icon will be dispalyed. */
+    public $_helpbutton = '';
+
+    /** @var array options provided to initalize filemanager */
+    // PHP doesn't support 'key' => $value1 | $value2 in class definition
+    // We cannot do $_options = array('return_types'=> FILE_INTERNAL | FILE_REFERENCE);
+    // So I have to set null here, and do it in constructor
+    protected $_options = array('mainfile' => '', 'subdirs' => 1, 'maxbytes' => -1, 'maxfiles' => -1,
+            'accepted_types' => '*', 'return_types' =>  null, 'areamaxbytes' => FILE_AREA_MAX_BYTES_UNLIMITED);
+
+    /**
+     * Constructor
+     *
+     * @param string $elementName (optional) name of the filemanager
+     * @param string $elementLabel (optional) filemanager label
+     * @param array $attributes (optional) Either a typical HTML attribute string
+     *              or an associative array
+     * @param array|stdClass $options set of options to initalize filemanager
+     */
+    public function __construct($elementName=null, $elementLabel=null, $attributes=null, $options=null) {
+        global $CFG, $PAGE;
+
+        $options = (array)$options;
+        foreach ($options as $name=>$value) {
+            if (array_key_exists($name, $this->_options)) {
+                $this->_options[$name] = $value;
+            }
+        }
+        if (!empty($options['maxbytes'])) {
+            $this->_options['maxbytes'] = get_user_max_upload_file_size($PAGE->context, $CFG->maxbytes, $options['maxbytes']);
+        }
+        if (empty($options['return_types'])) {
+            $this->_options['return_types'] = (FILE_INTERNAL | FILE_REFERENCE | FILE_CONTROLLED_LINK);
+        }
+        $this->_type = 'filemanager';
+        parent::__construct($elementName, $elementLabel, $attributes);
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_filemanager($elementName=null, $elementLabel=null, $attributes=null, $options=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $attributes, $options);
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return bool
+     */
+    function onQuickFormEvent($event, $arg, &$caller)
+    {
+        switch ($event) {
+            case 'createElement':
+                $caller->setType($arg[0], PARAM_INT);
+                break;
+        }
+        return parent::onQuickFormEvent($event, $arg, $caller);
+    }
+
+    /**
+     * Sets name of filemanager
+     *
+     * @param string $name name of the filemanager
+     */
+    function setName($name) {
+        $this->updateAttributes(array('name'=>$name));
+    }
+
+    /**
+     * Returns name of filemanager
+     *
+     * @return string
+     */
+    function getName() {
+        return $this->getAttribute('name');
+    }
+
+    /**
+     * Updates filemanager attribute value
+     *
+     * @param string $value value to set
+     */
+    function setValue($value) {
+        $this->updateAttributes(array('value'=>$value));
+    }
+
+    /**
+     * Returns filemanager attribute value
+     *
+     * @return string
+     */
+    function getValue() {
+        return $this->getAttribute('value');
+    }
+
+    /**
+     * Returns maximum file size which can be uploaded
+     *
+     * @return int
+     */
+    function getMaxbytes() {
+        return $this->_options['maxbytes'];
+    }
+
+    /**
+     * Sets maximum file size which can be uploaded
+     *
+     * @param int $maxbytes file size
+     */
+    function setMaxbytes($maxbytes) {
+        global $CFG, $PAGE;
+        $this->_options['maxbytes'] = get_user_max_upload_file_size($PAGE->context, $CFG->maxbytes, $maxbytes);
+    }
+
+    /**
+     * Returns the maximum size of the area.
+     *
+     * @return int
+     */
+    function getAreamaxbytes() {
+        return $this->_options['areamaxbytes'];
+    }
+
+    /**
+     * Sets the maximum size of the area.
+     *
+     * @param int $areamaxbytes size limit
+     */
+    function setAreamaxbytes($areamaxbytes) {
+        $this->_options['areamaxbytes'] = $areamaxbytes;
+    }
+
+    /**
+     * Returns true if subdirectoy can be created, else false
+     *
+     * @return bool
+     */
+    function getSubdirs() {
+        return $this->_options['subdirs'];
+    }
+
+    /**
+     * Set option to create sub directory, while uploading  file
+     *
+     * @param bool $allow true if sub directory can be created.
+     */
+    function setSubdirs($allow) {
+        $this->_options['subdirs'] = $allow;
+    }
+
+    /**
+     * Returns maximum number of files which can be uploaded
+     *
+     * @return int
+     */
+    function getMaxfiles() {
+        return $this->_options['maxfiles'];
+    }
+
+    /**
+     * Sets maximum number of files which can be uploaded.
+     *
+     * @param int $num number of files
+     */
+    function setMaxfiles($num) {
+        $this->_options['maxfiles'] = $num;
+    }
+
+    /**
+     * Returns html for help button.
+     *
+     * @return string html for help button
+     */
+    function getHelpButton() {
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Returns type of filemanager element
+     *
+     * @return string
+     */
+    function getElementTemplateType() {
+        if ($this->_flagFrozen){
+            return 'nodisplay';
+        } else {
+            return 'default';
+        }
+    }
+
+    /**
+     * Returns HTML for filemanager form element.
+     *
+     * @return string
+     */
+    function toHtml() {
+        global $CFG, $USER, $COURSE, $PAGE, $OUTPUT;
+        require_once("$CFG->dirroot/repository/lib.php");
+
+        // security - never ever allow guest/not logged in user to upload anything or use this element!
+        if (isguestuser() or !isloggedin()) {
+            throw new \moodle_exception('noguest');
+        }
+
+        if ($this->_flagFrozen) {
+            return $this->getFrozenHtml();
+        }
+
+        $id          = $this->_attributes['id'];
+        $elname      = $this->_attributes['name'];
+        $subdirs     = $this->_options['subdirs'];
+        $maxbytes    = $this->_options['maxbytes'];
+        $draftitemid = $this->getValue();
+        $accepted_types = $this->_options['accepted_types'];
+
+        if (empty($draftitemid)) {
+            // no existing area info provided - let's use fresh new draft area
+            require_once("$CFG->libdir/filelib.php");
+            $this->setValue(file_get_unused_draft_itemid());
+            $draftitemid = $this->getValue();
+        }
+
+        $client_id = uniqid();
+
+        // filemanager options
+        $options = new stdClass();
+        $options->mainfile  = $this->_options['mainfile'];
+        $options->maxbytes  = $this->_options['maxbytes'];
+        $options->maxfiles  = $this->getMaxfiles();
+        $options->client_id = $client_id;
+        $options->itemid    = $draftitemid;
+        $options->subdirs   = $this->_options['subdirs'];
+        $options->target    = $id;
+        $options->accepted_types = $accepted_types;
+        $options->return_types = $this->_options['return_types'];
+        $options->context = $PAGE->context;
+        $options->areamaxbytes = $this->_options['areamaxbytes'];
+
+        $html = $this->_getTabs();
+        $fm = new form_filemanager($options);
+        $output = $PAGE->get_renderer('core', 'files');
+        $html .= $output->render($fm);
+
+        $html .= html_writer::empty_tag('input', array('value' => $draftitemid, 'name' => $elname, 'type' => 'hidden', 'id' => $id));
+
+        if (!empty($options->accepted_types) && $options->accepted_types != '*') {
+            $html .= html_writer::tag('p', get_string('filesofthesetypes', 'form'));
+            $util = new \core_form\filetypes_util();
+            $filetypes = $options->accepted_types;
+            $filetypedescriptions = $util->describe_file_types($filetypes);
+            $html .= $OUTPUT->render_from_template('core_form/filetypes-descriptions', $filetypedescriptions);
+        }
+
+        return $html;
+    }
+
+    public function export_for_template(renderer_base $output) {
+        $context = $this->export_for_template_base($output);
+        $context['html'] = $this->toHtml();
+        return $context;
+    }
+
+    /**
+     * Check that all files have the allowed type.
+     *
+     * @param int $value Draft item id with the uploaded files.
+     * @return string|null Validation error message or null.
+     */
+    public function validateSubmitValue($value) {
+
+        if (empty($value)) {
+            return;
+        }
+
+        $filetypesutil = new \core_form\filetypes_util();
+        $allowlist = $filetypesutil->normalize_file_types($this->_options['accepted_types']);
+
+        if (empty($allowlist) || $allowlist === ['*']) {
+            // Any file type is allowed, nothing to check here.
+            return;
+        }
+
+        $draftfiles = file_get_all_files_in_draftarea($value);
+        $wrongfiles = array();
+
+        if (empty($draftfiles)) {
+            // No file uploaded, nothing to check here.
+            return;
+        }
+
+        foreach ($draftfiles as $file) {
+            if (!$filetypesutil->is_allowed_file_type($file->filename, $allowlist)) {
+                $wrongfiles[] = $file->filename;
+            }
+        }
+
+        if ($wrongfiles) {
+            $a = array(
+                'allowlist' => implode(', ', $allowlist),
+                'wrongfiles' => implode(', ', $wrongfiles),
+            );
+            return get_string('err_wrongfileextension', 'core_form', $a);
+        }
+
+        return;
+    }
+}
+
+/**
+ * Data structure representing a file manager.
+ *
+ * This class defines the data structure for file mnager
+ *
+ * @package   core_form
+ * @copyright 2010 Dongsheng Cai
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @todo      do not use this abstraction (skodak)
+ */
+class form_filemanager implements renderable {
+    /** @var stdClass $options options for filemanager */
+    public $options;
+
+    /**
+     * Constructor
+     *
+     * @param stdClass $options options for filemanager
+     *   default options are:
+     *       maxbytes=>-1,
+     *       areamaxbytes => FILE_AREA_MAX_BYTES_UNLIMITED,
+     *       maxfiles=>-1,
+     *       itemid=>0,
+     *       subdirs=>false,
+     *       client_id=>uniqid(),
+     *       acepted_types=>'*',
+     *       return_types=>FILE_INTERNAL,
+     *       context=>$PAGE->context,
+     *       author=>fullname($USER),
+     *       licenses=>array build from $CFG->licenses,
+     *       defaultlicense=>$CFG->sitedefaultlicense
+     */
+    public function __construct(stdClass $options) {
+        global $CFG, $USER, $PAGE;
+        require_once($CFG->dirroot. '/repository/lib.php');
+        require_once($CFG->libdir . '/licenselib.php');
+        $defaults = array(
+            'maxbytes'=>-1,
+            'areamaxbytes' => FILE_AREA_MAX_BYTES_UNLIMITED,
+            'maxfiles'=>-1,
+            'itemid'=>0,
+            'subdirs'=>0,
+            'client_id'=>uniqid(),
+            'accepted_types'=>'*',
+            'return_types'=>FILE_INTERNAL,
+            'context'=>$PAGE->context,
+            'author'=>fullname($USER),
+            'licenses'=>array()
+            );
+
+        $defaults['licenses'] = license_manager::get_licenses();
+
+        if (!empty($CFG->sitedefaultlicense)) {
+            $defaults['defaultlicense'] = $CFG->sitedefaultlicense;
+        }
+        foreach ($defaults as $key=>$value) {
+            // Using !isset() prevents us from overwriting falsey values with defaults (as empty() did).
+            if (!isset($options->$key)) {
+                $options->$key = $value;
+            }
+        }
+
+        $fs = get_file_storage();
+
+        // initilise options, getting files in root path
+        $this->options = file_get_drafarea_files($options->itemid, '/');
+
+        // calculate file count
+        $usercontext = context_user::instance($USER->id);
+        $files = $fs->get_area_files($usercontext->id, 'user', 'draft', $options->itemid, 'id', false);
+        $filecount = count($files);
+        $this->options->filecount = $filecount;
+
+        // copying other options
+        foreach ($options as $name=>$value) {
+            $this->options->$name = $value;
+        }
+
+        // calculate the maximum file size as minimum from what is specified in filepicker options,
+        // course options, global configuration and php settings
+        $coursebytes = $maxbytes = 0;
+        list($context, $course, $cm) = get_context_info_array($this->options->context->id);
+        if (is_object($course)) {
+            $coursebytes = $course->maxbytes;
+        }
+        if (!empty($this->options->maxbytes) && $this->options->maxbytes > 0) {
+            $maxbytes = $this->options->maxbytes;
+        }
+        $this->options->maxbytes = get_user_max_upload_file_size($context, $CFG->maxbytes, $coursebytes, $maxbytes);
+
+        $this->options->userprefs = array();
+        $this->options->userprefs['recentviewmode'] = get_user_preferences('filemanager_recentviewmode', '');
+
+        // building file picker options
+        $params = new stdClass();
+        $params->accepted_types = $options->accepted_types;
+        $params->return_types = $options->return_types;
+        $params->context = $options->context;
+        $params->env = 'filemanager';
+        $params->disable_types = !empty($options->disable_types)?$options->disable_types:array();
+        $filepicker_options = initialise_filepicker($params);
+        $this->options->filepicker = $filepicker_options;
+    }
+
+    public function get_nonjsurl() {
+        global $PAGE;
+        return new moodle_url('/repository/draftfiles_manager.php', array(
+            'env'=>'filemanager',
+            'action'=>'browse',
+            'itemid'=>$this->options->itemid,
+            'subdirs'=>$this->options->subdirs,
+            'maxbytes'=>$this->options->maxbytes,
+            'areamaxbytes' => $this->options->areamaxbytes,
+            'maxfiles'=>$this->options->maxfiles,
+            'ctx_id'=>$PAGE->context->id, // TODO ?
+            'course'=>$PAGE->course->id, // TODO ?
+            'sesskey'=>sesskey(),
+            ));
+    }
+}

lib/form/filepicker.js

@@ -0,0 +1,64 @@
+
+M.form_filepicker = {};
+M.form_filepicker.Y = null;
+M.form_filepicker.instances = [];
+
+M.form_filepicker.callback = function(params) {
+    var html = '<a href="'+params['url']+'">'+params['file']+'</a>';
+    html += '<div class="dndupload-progressbars"></div>';
+    M.form_filepicker.Y.one('#file_info_'+params['client_id'] + ' .filepicker-filename').setContent(html);
+    //When file is added then set status of global variable to true
+    var elementid = M.core_filepicker.instances[params['client_id']].options.elementid;
+    M.form_filepicker.instances[elementid].fileadded = true;
+    //generate event to indicate changes which will be used by disable if or validation code
+    M.form_filepicker.Y.one('#'+elementid).simulate('change');
+};
+
+/**
+ * This fucntion is called for each file picker on page.
+ */
+M.form_filepicker.init = function(Y, options) {
+    //Keep reference of YUI, so that it can be used in callback.
+    M.form_filepicker.Y = Y;
+
+    //For client side validation, initialize file status for this filepicker
+    M.form_filepicker.instances[options.elementid] = {};
+    M.form_filepicker.instances[options.elementid].fileadded = false;
+
+    //Set filepicker callback
+    options.formcallback = M.form_filepicker.callback;
+
+    if (!M.core_filepicker.instances[options.client_id]) {
+        M.core_filepicker.init(Y, options);
+    }
+    Y.on('click', function(e, client_id) {
+        e.preventDefault();
+        if (this.ancestor('.fitem.disabled') == null) {
+            M.core_filepicker.instances[client_id].show();
+        }
+    }, '#filepicker-button-'+options.client_id, null, options.client_id);
+
+    var item = document.getElementById('nonjs-filepicker-'+options.client_id);
+    if (item) {
+        item.parentNode.removeChild(item);
+    }
+    item = document.getElementById('filepicker-wrapper-'+options.client_id);
+    if (item) {
+        item.style.display = '';
+    }
+
+    var dndoptions = {
+        clientid: options.client_id,
+        acceptedtypes: options.accepted_types,
+        author: options.author,
+        maxfiles: -1,
+        maxbytes: options.maxbytes,
+        itemid: options.itemid,
+        repositories: options.repositories,
+        formcallback: options.formcallback,
+        containerprefix: '#file_info_',
+        containerid: 'file_info_'+options.client_id,
+        contextid: options.context.id
+    };
+    M.form_dndupload.init(Y, dndoptions);
+};

lib/form/filepicker.php

@@ -0,0 +1,281 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Filepicker form element
+ *
+ * Contains HTML class for a single filepicker form element
+ *
+ * @package   core_form
+ * @copyright 2009 Dongsheng Cai <dongsheng@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+
+require_once("HTML/QuickForm/button.php");
+require_once($CFG->dirroot.'/repository/lib.php');
+require_once('templatable_form_element.php');
+
+/**
+ * Filepicker form element
+ *
+ * HTML class for a single filepicker element (based on button)
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2009 Dongsheng Cai <dongsheng@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_filepicker extends HTML_QuickForm_input implements templatable {
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+    /** @var string html for help button, if empty then no help will icon will be dispalyed. */
+    public $_helpbutton = '';
+
+    /** @var array options provided to initalize filemanager */
+    // PHP doesn't support 'key' => $value1 | $value2 in class definition
+    // We cannot do $_options = array('return_types'=> FILE_INTERNAL | FILE_REFERENCE);
+    // So I have to set null here, and do it in constructor
+    protected $_options    = array('maxbytes'=>0, 'accepted_types'=>'*', 'return_types'=>null);
+
+    /**
+     * Constructor
+     *
+     * @param string $elementName (optional) name of the filepicker
+     * @param string $elementLabel (optional) filepicker label
+     * @param array $attributes (optional) Either a typical HTML attribute string
+     *              or an associative array
+     * @param array $options set of options to initalize filepicker
+     */
+    public function __construct($elementName=null, $elementLabel=null, $attributes=null, $options=null) {
+        global $CFG, $PAGE;
+
+        $options = (array)$options;
+        foreach ($options as $name=>$value) {
+            if (array_key_exists($name, $this->_options)) {
+                $this->_options[$name] = $value;
+            }
+        }
+        if (empty($options['return_types'])) {
+            $this->_options['return_types'] = FILE_INTERNAL;
+        }
+        $fpmaxbytes = 0;
+        if (!empty($options['maxbytes'])) {
+            $fpmaxbytes = $options['maxbytes'];
+        }
+        $coursemaxbytes = 0;
+        if (!empty($PAGE->course->maxbytes)) {
+            $coursemaxbytes = $PAGE->course->maxbytes;
+        }
+        $this->_options['maxbytes'] = get_user_max_upload_file_size($PAGE->context, $CFG->maxbytes, $coursemaxbytes, $fpmaxbytes);
+        $this->_type = 'filepicker';
+        parent::__construct($elementName, $elementLabel, $attributes);
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_filepicker($elementName=null, $elementLabel=null, $attributes=null, $options=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $attributes, $options);
+    }
+
+    /**
+     * Returns html for help button.
+     *
+     * @return string html for help button
+     */
+    function getHelpButton() {
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Returns type of filepicker element
+     *
+     * @return string
+     */
+    function getElementTemplateType() {
+        if ($this->_flagFrozen){
+            return 'nodisplay';
+        } else {
+            return 'default';
+        }
+    }
+
+    /**
+     * Returns HTML for filepicker form element.
+     *
+     * @return string
+     */
+    function toHtml() {
+        global $CFG, $COURSE, $USER, $PAGE, $OUTPUT;
+        $id     = $this->_attributes['id'];
+        $elname = $this->_attributes['name'];
+
+        if ($this->_flagFrozen) {
+            return $this->getFrozenHtml();
+        }
+        if (!$draftitemid = (int)$this->getValue()) {
+            // no existing area info provided - let's use fresh new draft area
+            $draftitemid = file_get_unused_draft_itemid();
+            $this->setValue($draftitemid);
+        }
+
+        if ($COURSE->id == SITEID) {
+            $context = context_system::instance();
+        } else {
+            $context = context_course::instance($COURSE->id);
+        }
+
+        $client_id = uniqid();
+
+        $args = new stdClass();
+        // need these three to filter repositories list
+        $args->accepted_types = $this->_options['accepted_types']?$this->_options['accepted_types']:'*';
+        $args->return_types = $this->_options['return_types'];
+        $args->itemid = $draftitemid;
+        $args->maxbytes = $this->_options['maxbytes'];
+        $args->context = $PAGE->context;
+        $args->buttonname = $elname.'choose';
+        $args->elementid = $id;
+
+        $html = $this->_getTabs();
+        $fp = new file_picker($args);
+        $options = $fp->options;
+        $options->context = $PAGE->context;
+        $html .= $OUTPUT->render($fp);
+        $html .= '<input type="hidden" name="'.$elname.'" id="'.$id.'" value="'.$draftitemid.'" class="filepickerhidden"/>';
+
+        $module = array('name'=>'form_filepicker', 'fullpath'=>'/lib/form/filepicker.js', 'requires'=>array('core_filepicker', 'node', 'node-event-simulate', 'core_dndupload'));
+        $PAGE->requires->js_init_call('M.form_filepicker.init', array($fp->options), true, $module);
+
+        $nonjsfilepicker = new moodle_url('/repository/draftfiles_manager.php', array(
+            'env'=>'filepicker',
+            'action'=>'browse',
+            'itemid'=>$draftitemid,
+            'subdirs'=>0,
+            'maxbytes'=>$options->maxbytes,
+            'maxfiles'=>1,
+            'ctx_id'=>$PAGE->context->id,
+            'course'=>$PAGE->course->id,
+            'sesskey'=>sesskey(),
+            ));
+
+        // non js file picker
+        $html .= '<noscript>';
+        $html .= "<div><object type='text/html' data='$nonjsfilepicker' height='160' width='600' style='border:1px solid #000'></object></div>";
+        $html .= '</noscript>';
+
+        if (!empty($args->accepted_types) && $args->accepted_types != '*') {
+            $html .= html_writer::tag('p', get_string('filesofthesetypes', 'form'));
+            $util = new \core_form\filetypes_util();
+            $filetypedescriptions = $util->describe_file_types($args->accepted_types);
+            $html .= $OUTPUT->render_from_template('core_form/filetypes-descriptions', $filetypedescriptions);
+        }
+
+        return $html;
+    }
+
+    /**
+     * export uploaded file
+     *
+     * @param array $submitValues values submitted.
+     * @param bool $assoc specifies if returned array is associative
+     * @return array
+     */
+    function exportValue(&$submitValues, $assoc = false) {
+        global $USER;
+
+        $draftitemid = $this->_findValue($submitValues);
+        if (null === $draftitemid) {
+            $draftitemid = $this->getValue();
+        }
+
+        // make sure max one file is present and it is not too big
+        if (!is_null($draftitemid)) {
+            $fs = get_file_storage();
+            $usercontext = context_user::instance($USER->id);
+            if ($files = $fs->get_area_files($usercontext->id, 'user', 'draft', $draftitemid, 'id DESC', false)) {
+                $file = array_shift($files);
+                if ($this->_options['maxbytes']
+                    and $this->_options['maxbytes'] !== USER_CAN_IGNORE_FILE_SIZE_LIMITS
+                    and $file->get_filesize() > $this->_options['maxbytes']) {
+
+                    // bad luck, somebody tries to sneak in oversized file
+                    $file->delete();
+                }
+                foreach ($files as $file) {
+                    // only one file expected
+                    $file->delete();
+                }
+            }
+        }
+
+        return $this->_prepareValue($draftitemid, true);
+    }
+
+    public function export_for_template(renderer_base $output) {
+        $context = $this->export_for_template_base($output);
+        $context['html'] = $this->toHtml();
+        return $context;
+    }
+
+    /**
+     * Check that the file has the allowed type.
+     *
+     * @param array $value Draft item id with the uploaded files.
+     * @return string|null Validation error message or null.
+     */
+    public function validateSubmitValue($value) {
+
+        $filetypesutil = new \core_form\filetypes_util();
+        $allowlist = $filetypesutil->normalize_file_types($this->_options['accepted_types']);
+
+        if (empty($allowlist) || $allowlist === ['*']) {
+            // Any file type is allowed, nothing to check here.
+            return;
+        }
+
+        $draftfiles = file_get_drafarea_files($value);
+        $wrongfiles = array();
+
+        if (empty($draftfiles)) {
+            // No file uploaded, nothing to check here.
+            return;
+        }
+
+        foreach ($draftfiles->list as $file) {
+            if (!$filetypesutil->is_allowed_file_type($file->filename, $allowlist)) {
+                $wrongfiles[] = $file->filename;
+            }
+        }
+
+        if ($wrongfiles) {
+            $a = array(
+                'allowlist' => implode(', ', $allowlist),
+                'wrongfiles' => implode(', ', $wrongfiles),
+            );
+            return get_string('err_wrongfileextension', 'core_form', $a);
+        }
+
+        return;
+    }
+}

lib/form/filetypes.php

@@ -0,0 +1,254 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Provides the {@link MoodleQuickForm_filetypes} class.
+ *
+ * @package   core_form
+ * @copyright 2016 Jonathon Fowler <fowlerj@usq.edu.au>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+use core_form\filetypes_util;
+
+defined('MOODLE_INTERNAL') || die;
+
+global $CFG;
+require_once($CFG->dirroot.'/lib/form/group.php');
+
+/**
+ * File types and type groups selection form element.
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2016 Jonathon Fowler <fowlerj@usq.edu.au>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_filetypes extends MoodleQuickForm_group {
+
+    /** @var array Allow selection from these file types only. */
+    protected $onlytypes = [];
+
+    /** @var bool Allow selection of 'All file types' (will be stored as '*'). */
+    protected $allowall = true;
+
+    /** @var bool Skip implicit validation against known file types. */
+    protected $allowunknown = false;
+
+    /** @var core_form\filetypes_util instance to use as a helper. */
+    protected $util = null;
+
+    /**
+     * Constructor
+     *
+     * @param string $elementname Element's name
+     * @param string $elementlabel Label(s) for an element
+     * @param array $options element options:
+     *   'onlytypes': Allow selection from these file types only; for example ['onlytypes' => ['web_image']].
+     *   'allowall': Allow to select 'All file types', defaults to true. Does not apply with onlytypes are set.
+     *   'allowunknown': Skip implicit validation against the list of known file types.
+     * @param array|string $attributes Either a typical HTML attribute string or an associative array
+     */
+    public function __construct($elementname = null, $elementlabel = null, $options = null, $attributes = null) {
+
+        parent::__construct($elementname, $elementlabel);
+        $this->_type = 'filetypes';
+
+        // Hard-frozen elements do not get the name populated automatically,
+        // which leads to PHP notice. Add it explicitly here.
+        $this->setAttributes(array('name' => $elementname));
+        $this->updateAttributes($attributes);
+
+        if (is_array($options) && $options) {
+            if (array_key_exists('onlytypes', $options) && is_array($options['onlytypes'])) {
+                $this->onlytypes = $options['onlytypes'];
+            }
+            if (!$this->onlytypes && array_key_exists('allowall', $options)) {
+                $this->allowall = (bool)$options['allowall'];
+            }
+            if (array_key_exists('allowunknown', $options)) {
+                $this->allowunknown = (bool)$options['allowunknown'];
+            }
+        }
+
+        $this->util = new filetypes_util();
+    }
+
+    /**
+     * Assemble the elements of the form control.
+     */
+    public function _createElements() {
+
+        $this->_generateId();
+
+        $this->setElements([
+            $this->createFormElement('text', 'filetypes', $this->getLabel(), [
+                'id' => $this->getAttribute('id'),
+            ]),
+
+            $this->createFormElement('static', 'browser', null,
+                '<span data-filetypesbrowser="'.$this->getAttribute('id').'"></span>'),
+
+            $this->createFormElement('static', 'descriptions', null,
+                '<div data-filetypesdescriptions="'.$this->getAttribute('id').'"></div>')
+        ]);
+    }
+
+    /**
+     * Return the selected file types.
+     *
+     * @param array $submitted submitted values
+     * @param bool $assoc if true the retured value is associated array
+     * @return array
+     */
+    public function exportValue(&$submitted, $assoc = false) {
+
+        $value = '';
+        $filetypeselement = null;
+
+        foreach ($this->_elements as $key => $element) {
+            if ($element->_attributes['name'] === 'filetypes') {
+                $filetypeselement = $this->_elements[$key];
+            }
+        }
+
+        if ($filetypeselement) {
+            $formval = $filetypeselement->exportValue($submitted[$this->getName()], false);
+            if ($formval) {
+                $value = $this->util->normalize_file_types($formval);
+                if ($value === ['*'] && !$this->allowall) {
+                    $value = [];
+                }
+                $value = implode(',', $value);
+            }
+        }
+
+        return $this->_prepareValue($value, $assoc);
+    }
+
+    /**
+     * Accepts a renderer (called shortly before the renderer's toHtml() method).
+     *
+     * @param HTML_QuickForm_Renderer $renderer An HTML_QuickForm_Renderer object
+     * @param bool $required Whether a group is required
+     * @param string $error An error message associated with a group
+     */
+    public function accept(&$renderer, $required = false, $error = null) {
+        global $PAGE;
+
+        $PAGE->requires->js_call_amd('core_form/filetypes', 'init', [
+            $this->getAttribute('id'),
+            $this->getLabel(),
+            $this->onlytypes,
+            $this->allowall,
+        ]);
+
+        if ($this->isFrozen()) {
+            // Don't render the choose button if the control is frozen.
+            foreach ($this->_elements as $key => $element) {
+                if ($element->_attributes['name'] === 'browser') {
+                    unset($this->_elements[$key]);
+                }
+            }
+        }
+
+        parent::accept($renderer, $required, $error);
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return bool
+     */
+    public function onQuickFormEvent($event, $arg, &$caller) {
+        global $OUTPUT;
+
+        switch ($event) {
+            case 'updateValue':
+                $value = $this->_findValue($caller->_constantValues);
+                if (null === $value) {
+                    if ($caller->isSubmitted()) {
+                        $value = $this->_findValue($caller->_submitValues);
+                    } else {
+                        $value = (string)$this->_findValue($caller->_defaultValues);
+                    }
+                }
+                if (!is_array($value)) {
+                    $value = array('filetypes' => $value);
+                }
+                if ($value['filetypes'] !== null) {
+                    $filetypes = $this->util->normalize_file_types($value['filetypes']);
+                    if ($filetypes === ['*'] && !$this->allowall) {
+                        $filetypes = [];
+                    }
+                    $value['descriptions'] = '<div data-filetypesdescriptions="'.$this->getAttribute('id').'">' .
+                        $OUTPUT->render_from_template('core_form/filetypes-descriptions',
+                            $this->util->describe_file_types($filetypes)).'</div>';
+                }
+                $this->setValue($value);
+                return true;
+                break;
+
+        }
+
+        return parent::onQuickFormEvent($event, $arg, $caller);
+    }
+
+    /**
+     * Check that the submitted list contains only known and allowed file types.
+     *
+     * The validation obeys the element options 'allowall', 'allowunknown' and
+     * 'onlytypes' passed when creating the element.
+     *
+     * @param array $value Submitted value.
+     * @return string|null Validation error message or null.
+     */
+    public function validateSubmitValue($value) {
+
+        $value = $value ?? ['filetypes' => null]; // A null $value can arrive here. Coalesce, creating the default array.
+
+        if (!$this->allowall) {
+            // Assert that there is an actual list provided.
+            $normalized = $this->util->normalize_file_types($value['filetypes']);
+            if (empty($normalized) || $normalized == ['*']) {
+                return get_string('filetypesnotall', 'core_form');
+            }
+        }
+
+        if (!$this->allowunknown) {
+            // Assert that all file types are known.
+            $unknown = $this->util->get_unknown_file_types($value['filetypes']);
+
+            if ($unknown) {
+                return get_string('filetypesunknown', 'core_form', implode(', ', $unknown));
+            }
+        }
+
+        if ($this->onlytypes) {
+            // Assert that all file types are allowed here.
+            $notlisted = $this->util->get_not_listed($value['filetypes'], $this->onlytypes);
+
+            if ($notlisted) {
+                return get_string('filetypesnotallowed', 'core_form', implode(', ', $notlisted));
+            }
+        }
+
+        return;
+    }
+}

lib/form/float.php

@@ -0,0 +1,193 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Float type form element
+ *
+ * Contains HTML class for a float type element
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2019 Shamim Rezaie <shamim@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+global $CFG;
+require_once($CFG->libdir . '/form/text.php');
+
+/**
+ * Float type form element.
+ *
+ * This is preferred over the text element when working with float numbers, and takes care of the fact that different languages
+ * may use different symbols as the decimal separator.
+ * Using this element, submitted float numbers will be automatically translated from the localised format into the computer format,
+ * and vice versa when they are being displayed.
+ *
+ * @copyright 2019 Shamim Rezaie <shamim@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_float extends MoodleQuickForm_text {
+
+    /**
+     * MoodleQuickForm_float constructor.
+     *
+     * @param string $elementName (optional) name of the float field
+     * @param string $elementLabel (optional) float field label
+     * @param string $attributes (optional) Either a typical HTML attribute string or an associative array
+     */
+    public function __construct($elementName = null, $elementLabel = null, $attributes = null) {
+        parent::__construct($elementName, $elementLabel, $attributes);
+        $this->_type = 'float';
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element.
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return bool
+     */
+    public function onQuickFormEvent($event, $arg, &$caller) {
+        switch ($event) {
+            case 'updateValue':
+                if ($value = $this->_findValue($caller->_constantValues)) {
+                    $value = $this->format_float($value);
+                }
+                if (null === $value) {
+                    $value = $this->_findValue($caller->_submitValues);
+                    if (null === $value) {
+                        if ($value = $this->_findValue($caller->_defaultValues)) {
+                            $value = $this->format_float($value);
+                        }
+                    }
+                }
+                if (null !== $value) {
+                    parent::setValue($value);
+                }
+                return true;
+            case 'createElement':
+                $caller->setType($arg[0], PARAM_RAW_TRIMMED);
+            default:
+                return parent::onQuickFormEvent($event, $arg, $caller);
+        }
+    }
+
+    /**
+     * Checks that the submitted value is a valid float number.
+     *
+     * @param string $value The localised float number that is submitted.
+     * @return string|null Validation error message or null.
+     */
+    public function validateSubmitValue($value) {
+        if (false === unformat_float($value, true)) {
+            return get_string('err_numeric', 'core_form');
+        }
+    }
+
+    /**
+     * Sets the value of the form element.
+     *
+     * @param string $value Default value of the form element
+     */
+    public function setValue($value) {
+        $value = $this->format_float($value);
+        parent::setValue($value);
+    }
+
+    /**
+     * Returns the value of the form element.
+     *
+     * @return false|float
+     */
+    public function getValue() {
+        $value = parent::getValue();
+        if ($value) {
+            $value = unformat_float($value, true);
+        }
+        return $value;
+    }
+
+    /**
+     * Returns a 'safe' element's value.
+     *
+     * @param  array   $submitValues array of submitted values to search
+     * @param  bool    $assoc whether to return the value as associative array
+     * @return mixed
+     */
+    public function exportValue(&$submitValues, $assoc = false) {
+        $value = $this->_findValue($submitValues);
+        if (null === $value) {
+            $value = $this->getValue();
+        } else if ($value) {
+            $value = unformat_float($value, true);
+        }
+        return $this->_prepareValue($value, $assoc);
+    }
+
+    /**
+     * Used by getFrozenHtml() to pass the element's value if _persistantFreeze is on.
+     *
+     * @return string
+     */
+    public function _getPersistantData() {
+        if (!$this->_persistantFreeze) {
+            return '';
+        } else {
+            $id = $this->getAttribute('id');
+            if (isset($id)) {
+                // Id of persistant input is different then the actual input.
+                $id = array('id' => $id . '_persistant');
+            } else {
+                $id = array();
+            }
+
+            return '<input' . $this->_getAttrString(array(
+                        'type'  => 'hidden',
+                        'name'  => $this->getAttribute('name'),
+                        'value' => $this->getAttribute('value')
+                    ) + $id) . ' />';
+        }
+    }
+
+    /**
+     * Given a float, prints it nicely.
+     * This function reserves the number of decimal places.
+     *
+     * @param float|null $value The float number to format
+     * @return string Localised float
+     */
+    private function format_float($value) {
+        if (is_numeric($value)) {
+            // We want to keep trailing zeros after the decimal point if there is any.
+            // Therefore we cannot just call format_float() and pass -1 as the number of decimal points.
+            $pieces = preg_split('/E/i', $value); // In case it is in the scientific format.
+            $decimalpos = strpos($pieces[0], '.');
+            if ($decimalpos !== false) {
+                $decimalpart = substr($pieces[0], $decimalpos + 1);
+                $decimals = strlen($decimalpart);
+            } else {
+                $decimals = 0;
+            }
+            $pieces[0] = format_float($pieces[0], $decimals);
+            $value = implode('E', $pieces);
+        }
+        return $value;
+    }
+}

lib/form/form.js

@@ -0,0 +1,743 @@
+/**
+ * This file contains JS functionality required by mforms and is included automatically
+ * when required.
+ */
+
+// Namespace for the form bits and bobs
+M.form = M.form || {};
+
+if (typeof M.form.dependencyManager === 'undefined') {
+    var dependencyManager = function() {
+        dependencyManager.superclass.constructor.apply(this, arguments);
+    };
+    Y.extend(dependencyManager, Y.Base, {
+        _locks: null,
+        _hides: null,
+        _dirty: null,
+        _nameCollections: null,
+        _fileinputs: null,
+        _staticElements: null,
+        _editors: null,
+        _editorNameSuffix: '[text]',
+
+        initializer: function() {
+            // Setup initial values for complex properties.
+            this._locks = {};
+            this._hides = {};
+            this._dirty = {};
+
+            // Setup event handlers.
+            Y.Object.each(this.get('dependencies'), function(value, i) {
+                var elements = this.elementsByName(i);
+                elements.each(function(node) {
+                    var nodeName = node.get('nodeName').toUpperCase();
+                    if (nodeName == 'INPUT') {
+                        if (node.getAttribute('type').match(/^(button|submit|radio|checkbox)$/)) {
+                            node.on('click', this.updateEventDependencies, this);
+                        } else {
+                            node.on('blur', this.updateEventDependencies, this);
+                        }
+                        node.on('change', this.updateEventDependencies, this);
+                    } else if (nodeName == 'SELECT') {
+                        node.on('change', this.updateEventDependencies, this);
+                    } else {
+                        node.on('click', this.updateEventDependencies, this);
+                        node.on('blur', this.updateEventDependencies, this);
+                        node.on('change', this.updateEventDependencies, this);
+                    }
+                }, this);
+            }, this);
+
+            // Handle the reset button.
+            this.get('form').get('elements').each(function(input) {
+                if (input.getAttribute('type') == 'reset') {
+                    input.on('click', function() {
+                        this.get('form').reset();
+                        this.updateAllDependencies();
+                    }, this);
+                }
+            }, this);
+
+            this.updateAllDependencies();
+        },
+
+        /**
+         * Initializes the mapping from element name to YUI NodeList
+         */
+        initElementsByName: function() {
+            var names = {}; // Form elements with a given name.
+            var allnames = {}; // Form elements AND outer elements for groups with a given name.
+
+            // Collect element names.
+            Y.Object.each(this.get('dependencies'), function(conditions, i) {
+                names[i] = new Y.NodeList();
+                allnames[i] = new Y.NodeList();
+                for (var condition in conditions) {
+                    for (var value in conditions[condition]) {
+                        for (var hide in conditions[condition][value]) {
+                            for (var ei in conditions[condition][value][hide]) {
+                                names[conditions[condition][value][hide][ei]] = new Y.NodeList();
+                                allnames[conditions[condition][value][hide][ei]] = new Y.NodeList();
+                            }
+                        }
+                    }
+                }
+            });
+
+            // Locate elements for each name.
+            this.get('form').get('elements').each(function(node) {
+                var name = node.getAttribute('name');
+                if (({}).hasOwnProperty.call(names, name)) {
+                    names[name].push(node);
+                    allnames[name].push(node);
+                } else if (this.isEditor(name)) {
+                    // If this is an editor, we need to remove the suffix.
+                    name = name.replace(this._editorNameSuffix, '');
+                    if (({}).hasOwnProperty.call(names, name)) {
+                        names[name].push(node);
+                        allnames[name].push(node);
+                    }
+                }
+            }, this);
+            // Locate any groups with the given name.
+            this.get('form').all('.fitem').each(function(node) {
+                var name = node.getData('groupname');
+                if (name && ({}).hasOwnProperty.call(allnames, name)) {
+                    allnames[name].push(node);
+                }
+            });
+            // Locate any static elements for each name.
+            this.get('form').all('.form-control-static').each(function(node) {
+                var name = node.getData('name');
+                if (({}).hasOwnProperty.call(allnames, name)) {
+                    names[name].push(node);
+                    allnames[name].push(node);
+                }
+            });
+            this._nameCollections = {names: names, allnames: allnames};
+        },
+
+        /**
+         * Gets all elements in the form by their name and returns
+         * a YUI NodeList
+         *
+         * @param {String} name The form element name.
+         * @param {Boolean} includeGroups (optional - default false) Should the outer element for groups be included?
+         * @return {Y.NodeList}
+         */
+        elementsByName: function(name, includeGroups) {
+            if (includeGroups === undefined) {
+                includeGroups = false;
+            }
+            var collection = (includeGroups ? 'allnames' : 'names');
+
+            if (!this._nameCollections) {
+                this.initElementsByName();
+            }
+            if (!({}).hasOwnProperty.call(this._nameCollections[collection], name)) {
+                return new Y.NodeList();
+            }
+            return this._nameCollections[collection][name];
+        },
+
+        /**
+         * Checks the dependencies the form has an makes any changes to the
+         * form that are required.
+         *
+         * Changes are made by functions title _dependency{Dependencytype}
+         * and more can easily be introduced by defining further functions.
+         *
+         * @param {EventFacade | null} e The event, if any.
+         * @param {String} dependon The form element name to check dependencies against.
+         * @return {Boolean}
+         */
+        checkDependencies: function(e, dependon) {
+            var dependencies = this.get('dependencies'),
+                tohide = {},
+                tolock = {},
+                condition, value, isHide, lock, hide,
+                checkfunction, result, elements;
+            if (!({}).hasOwnProperty.call(dependencies, dependon)) {
+                return true;
+            }
+            elements = this.elementsByName(dependon);
+            for (condition in dependencies[dependon]) {
+                for (value in dependencies[dependon][condition]) {
+                    for (isHide in dependencies[dependon][condition][value]) {
+                        checkfunction = '_dependency' + condition[0].toUpperCase() + condition.slice(1);
+                        if (Y.Lang.isFunction(this[checkfunction])) {
+                            result = this[checkfunction].apply(this, [elements, value, (isHide === "1"), e]);
+                        } else {
+                            result = this._dependencyDefault(elements, value, (isHide === "1"), e);
+                        }
+                        lock = result.lock || false;
+                        hide = result.hide || false;
+                        for (var ei in dependencies[dependon][condition][value][isHide]) {
+                            var eltolock = dependencies[dependon][condition][value][isHide][ei];
+                            if (({}).hasOwnProperty.call(tohide, eltolock)) {
+                                tohide[eltolock] = tohide[eltolock] || hide;
+                            } else {
+                                tohide[eltolock] = hide;
+                            }
+
+                            if (({}).hasOwnProperty.call(tolock, eltolock)) {
+                                tolock[eltolock] = tolock[eltolock] || lock;
+                            } else {
+                                tolock[eltolock] = lock;
+                            }
+                        }
+                    }
+                }
+            }
+
+            for (var el in tolock) {
+                var needsupdate = false;
+                if (!({}).hasOwnProperty.call(this._locks, el)) {
+                    this._locks[el] = {};
+                }
+                if (({}).hasOwnProperty.call(tolock, el) && tolock[el]) {
+                    if (!({}).hasOwnProperty.call(this._locks[el], dependon) || this._locks[el][dependon]) {
+                        this._locks[el][dependon] = true;
+                        needsupdate = true;
+                    }
+                } else if (({}).hasOwnProperty.call(this._locks[el], dependon) && this._locks[el][dependon]) {
+                    delete this._locks[el][dependon];
+                    needsupdate = true;
+                }
+
+                if (!({}).hasOwnProperty.call(this._hides, el)) {
+                    this._hides[el] = {};
+                }
+                if (({}).hasOwnProperty.call(tohide, el) && tohide[el]) {
+                    if (!({}).hasOwnProperty.call(this._hides[el], dependon) || this._hides[el][dependon]) {
+                        this._hides[el][dependon] = true;
+                        needsupdate = true;
+                    }
+                } else if (({}).hasOwnProperty.call(this._hides[el], dependon) && this._hides[el][dependon]) {
+                    delete this._hides[el][dependon];
+                    needsupdate = true;
+                }
+
+                if (needsupdate) {
+                    this._dirty[el] = true;
+                }
+            }
+
+            return true;
+        },
+        /**
+         * Update all dependencies in form
+         */
+        updateAllDependencies: function() {
+            Y.Object.each(this.get('dependencies'), function(value, name) {
+                this.checkDependencies(null, name);
+            }, this);
+
+            this.updateForm();
+        },
+        /**
+         * Update dependencies associated with event
+         *
+         * @param {Event} e The event.
+         */
+        updateEventDependencies: function(e) {
+            var el = e.target.getAttribute('name');
+            this.checkDependencies(e, el);
+            this.updateForm();
+        },
+        /**
+         * Flush pending changes to the form
+         */
+        updateForm: function() {
+            var el;
+            for (el in this._dirty) {
+                if (({}).hasOwnProperty.call(this._locks, el)) {
+                    this._disableElement(el, !Y.Object.isEmpty(this._locks[el]));
+                }
+                if (({}).hasOwnProperty.call(this._hides, el)) {
+                    this._hideElement(el, !Y.Object.isEmpty(this._hides[el]));
+                }
+            }
+
+            this._dirty = {};
+        },
+        /**
+         * Disables or enables all form elements with the given name
+         *
+         * @param {String} name The form element name.
+         * @param {Boolean} disabled True to disable, false to enable.
+         */
+        _disableElement: function(name, disabled) {
+            const els = this.elementsByName(name),
+                filepicker = this.isFilePicker(name),
+                editors = this.get('form').all('.fitem [data-fieldtype="editor"] textarea[name="' + name + '[text]"]'),
+                staticElement = this.isStaticElement(name);
+
+            els.each(function(node) {
+                const fitem = node.ancestor('.fitem');
+                if (disabled) {
+                    node.setAttribute('disabled', 'disabled');
+                } else {
+                    node.removeAttribute('disabled');
+                }
+                // Enable/Disable static elements if exist.
+                if (staticElement) {
+                    const disabledNonTextElements = 'INPUT,SELECT,TEXTAREA,BUTTON,A';
+                    if (disabled) {
+                        // Mute the text inside the current static element.
+                        fitem.addClass('text-muted');
+                        // Disabled non-text elements in the static if exist.
+                        fitem.all(disabledNonTextElements).each(function(disabledElement) {
+                            if (disabledElement.get('tagName').toUpperCase() === "A") {
+                                disabledElement.addClass('disabled');
+                            } else {
+                                disabledElement.setAttribute('disabled', 'disabled');
+                            }
+                        });
+                    } else {
+                        // Unmute the text inside the current static element.
+                        fitem.removeClass('text-muted');
+                        // Enabled non-text elements in the static if exist.
+                        fitem.all(disabledNonTextElements).each(function(disabledElement) {
+                            if (disabledElement.get('tagName').toUpperCase() === "A") {
+                                disabledElement.removeClass('disabled');
+                            } else {
+                                disabledElement.removeAttribute('disabled', 'disabled');
+                            }
+                        });
+                    }
+                }
+                // Extra code to disable filepicker or filemanager form elements
+                if (filepicker) {
+                    if (fitem) {
+                        if (disabled) {
+                            fitem.addClass('disabled');
+                        } else {
+                            fitem.removeClass('disabled');
+                        }
+                    }
+                }
+            });
+            editors.each(function(editor) {
+                if (disabled) {
+                    editor.setAttribute('readonly', 'readonly');
+                } else {
+                    editor.removeAttribute('readonly', 'readonly');
+                }
+                editor.getDOMNode().dispatchEvent(new Event('form:editorUpdated'));
+            });
+        },
+        /**
+         * Hides or shows all form elements with the given name.
+         *
+         * @param {String} name The form element name.
+         * @param {Boolean} hidden True to hide, false to show.
+         */
+        _hideElement: function(name, hidden) {
+            var els = this.elementsByName(name, true);
+            els.each(function(node) {
+                var e = node.ancestor('.fitem', true);
+                var label = null,
+                    id = null;
+                if (e) {
+                    // Cope with differences between clean and boost themes.
+                    if (e.hasClass('fitem_fgroup')) {
+                        // Items within groups are not wrapped in div.fitem in theme_clean, so
+                        // we need to hide the input, not the div.fitem.
+                        e = node;
+                    }
+
+                    if (hidden) {
+                        e.setAttribute('hidden', 'hidden');
+                    } else {
+                        e.removeAttribute('hidden');
+                    }
+                    e.setStyles({
+                        display: (hidden) ? 'none' : ''
+                    });
+
+                    // Hide/unhide the label as well.
+                    id = node.get('id');
+                    if (id) {
+                        label = Y.all('label[for="' + id + '"]');
+                        if (label) {
+                            if (hidden) {
+                                label.setAttribute('hidden', 'hidden');
+                            } else {
+                                label.removeAttribute('hidden');
+                            }
+                            label.setStyles({
+                                display: (hidden) ? 'none' : ''
+                            });
+                        }
+                    }
+                }
+            });
+        },
+        /**
+         * Is the form element inside a filepicker or filemanager?
+         *
+         * @param {String} el The form element name.
+         * @return {Boolean}
+         */
+        isFilePicker: function(el) {
+            if (!this._fileinputs) {
+                var fileinputs = {};
+                var selector = '.fitem [data-fieldtype="filepicker"] input,.fitem [data-fieldtype="filemanager"] input';
+                // Include a selector where the filemanager input is nested in a group.
+                selector += ',.fitem [data-fieldtype="group"] input[id*="filemanager"]';
+                var els = this.get('form').all(selector);
+                els.each(function(node) {
+                    fileinputs[node.getAttribute('name')] = true;
+                });
+                this._fileinputs = fileinputs;
+            }
+
+            if (({}).hasOwnProperty.call(this._fileinputs, el)) {
+                return this._fileinputs[el] || false;
+            }
+
+            return false;
+        },
+        /**
+         * Checks if a form element with the given name is static.
+         *
+         * @param {string} el - The name of the form element to check.
+         * @returns {boolean} - Returns true if the form element is static, otherwise false.
+         */
+        isStaticElement: function(el) {
+            if (!this._staticElements) {
+                const staticElements = {};
+                const els = this.get('form').all('.fitem [data-fieldtype="static"] .form-control-static');
+                els.each(function(node) {
+                    if (node.getData('name') === el) {
+                        staticElements[node.getData('name')] = true;
+                    }
+                });
+                this._staticElements = staticElements;
+            }
+            if (({}).hasOwnProperty.call(this._staticElements, el)) {
+                return this._staticElements[el] || false;
+            }
+            return false;
+        },
+        _dependencyNotchecked: function(elements, value, isHide) {
+            var lock = false;
+            elements.each(function() {
+                if (this.getAttribute('type').toLowerCase() == 'hidden' &&
+                        !this.siblings('input[type=checkbox][name="' + this.get('name') + '"]').isEmpty()) {
+                    // This is the hidden input that is part of an advcheckbox.
+                    return;
+                }
+                if (this.getAttribute('type').toLowerCase() == 'radio' && this.get('value') != value) {
+                    return;
+                }
+                lock = lock || !Y.Node.getDOMNode(this).checked;
+            });
+            return {
+                lock: lock,
+                hide: isHide ? lock : false
+            };
+        },
+        _dependencyChecked: function(elements, value, isHide) {
+            var lock = false;
+            elements.each(function() {
+                if (this.getAttribute('type').toLowerCase() == 'hidden' &&
+                        !this.siblings('input[type=checkbox][name="' + this.get('name') + '"]').isEmpty()) {
+                    // This is the hidden input that is part of an advcheckbox.
+                    return;
+                }
+                if (this.getAttribute('type').toLowerCase() == 'radio' && this.get('value') != value) {
+                    return;
+                }
+                lock = lock || Y.Node.getDOMNode(this).checked;
+            });
+            return {
+                lock: lock,
+                hide: isHide ? lock : false
+            };
+        },
+        _dependencyNoitemselected: function(elements, value, isHide) {
+            var lock = false;
+            elements.each(function() {
+                lock = lock || this.get('selectedIndex') == -1;
+            });
+            return {
+                lock: lock,
+                hide: isHide ? lock : false
+            };
+        },
+        _dependencyEq: function(elements, value, isHide) {
+            var lock = false;
+            var hiddenVal = false;
+            var options, v, selected, values;
+            elements.each(function() {
+                if (this.getAttribute('type').toLowerCase() == 'radio' && !Y.Node.getDOMNode(this).checked) {
+                    return;
+                } else if (this.getAttribute('type').toLowerCase() == 'hidden' &&
+                        !this.siblings('input[type=checkbox][name="' + this.get('name') + '"]').isEmpty()) {
+                    // This is the hidden input that is part of an advcheckbox.
+                    hiddenVal = (this.get('value') == value);
+                    return;
+                } else if (this.getAttribute('type').toLowerCase() == 'checkbox' && !Y.Node.getDOMNode(this).checked) {
+                    lock = lock || hiddenVal;
+                    return;
+                }
+                if (this.getAttribute('class').toLowerCase() == 'filepickerhidden') {
+                    // Check for filepicker status.
+                    var elementname = this.getAttribute('name');
+                    if (elementname && M.form_filepicker.instances[elementname].fileadded) {
+                        lock = false;
+                    } else {
+                        lock = true;
+                    }
+                } else if (this.get('nodeName').toUpperCase() === 'SELECT' && this.get('multiple') === true) {
+                    // Multiple selects can have one or more value assigned. A pipe (|) is used as a value separator
+                    // when multiple values have to be selected at the same time.
+                    values = value.split('|');
+                    selected = [];
+                    options = this.get('options');
+                    options.each(function() {
+                        if (this.get('selected')) {
+                            selected[selected.length] = this.get('value');
+                        }
+                    });
+                    if (selected.length > 0 && selected.length === values.length) {
+                        for (var i in selected) {
+                            v = selected[i];
+                            if (values.indexOf(v) > -1) {
+                                lock = true;
+                            } else {
+                                lock = false;
+                                return;
+                            }
+                        }
+                    } else {
+                        lock = false;
+                    }
+                } else {
+                    lock = lock || this.get('value') == value;
+                }
+            });
+            return {
+                lock: lock,
+                hide: isHide ? lock : false
+            };
+        },
+        /**
+         * Lock the given field if the field value is in the given set of values.
+         *
+         * @param {Array} elements
+         * @param {String} values Single value or pipe (|) separated values when multiple
+         * @returns {{lock: boolean, hide: boolean}}
+         * @private
+         */
+        _dependencyIn: function(elements, values, isHide) {
+            // A pipe (|) is used as a value separator
+            // when multiple values have to be passed on at the same time.
+            values = values.split('|');
+            var lock = false;
+            var hiddenVal = false;
+            var options, v, selected, value;
+            elements.each(function() {
+                if (this.getAttribute('type').toLowerCase() == 'radio' && !Y.Node.getDOMNode(this).checked) {
+                    return;
+                } else if (this.getAttribute('type').toLowerCase() == 'hidden' &&
+                        !this.siblings('input[type=checkbox][name="' + this.get('name') + '"]').isEmpty()) {
+                    // This is the hidden input that is part of an advcheckbox.
+                    hiddenVal = (values.indexOf(this.get('value')) > -1);
+                    return;
+                } else if (this.getAttribute('type').toLowerCase() == 'checkbox' && !Y.Node.getDOMNode(this).checked) {
+                    lock = lock || hiddenVal;
+                    return;
+                }
+                if (this.getAttribute('class').toLowerCase() == 'filepickerhidden') {
+                    // Check for filepicker status.
+                    var elementname = this.getAttribute('name');
+                    if (elementname && M.form_filepicker.instances[elementname].fileadded) {
+                        lock = false;
+                    } else {
+                        lock = true;
+                    }
+                } else if (this.get('nodeName').toUpperCase() === 'SELECT' && this.get('multiple') === true) {
+                    // Multiple selects can have one or more value assigned.
+                    selected = [];
+                    options = this.get('options');
+                    options.each(function() {
+                        if (this.get('selected')) {
+                            selected[selected.length] = this.get('value');
+                        }
+                    });
+                    if (selected.length > 0 && selected.length === values.length) {
+                        for (var i in selected) {
+                            v = selected[i];
+                            if (values.indexOf(v) > -1) {
+                                lock = true;
+                            } else {
+                                lock = false;
+                                return;
+                            }
+                        }
+                    } else {
+                        lock = false;
+                    }
+                } else {
+                    value = this.get('value');
+                    lock = lock || (values.indexOf(value) > -1);
+                }
+            });
+            return {
+                lock: lock,
+                hide: isHide ? lock : false
+            };
+        },
+        _dependencyHide: function(elements, value) {
+            return {
+                lock: false,
+                hide: true
+            };
+        },
+        _dependencyDefault: function(elements, value, isHide) {
+            var lock = false,
+                hiddenVal = false,
+                values
+                ;
+            elements.each(function() {
+                var selected;
+                if (this.getAttribute('type').toLowerCase() == 'radio' && !Y.Node.getDOMNode(this).checked) {
+                    return;
+                } else if (this.getAttribute('type').toLowerCase() == 'hidden' &&
+                        !this.siblings('input[type=checkbox][name="' + this.get('name') + '"]').isEmpty()) {
+                    // This is the hidden input that is part of an advcheckbox.
+                    hiddenVal = (this.get('value') != value);
+                    return;
+                } else if (this.getAttribute('type').toLowerCase() == 'checkbox' && !Y.Node.getDOMNode(this).checked) {
+                    lock = lock || hiddenVal;
+                    return;
+                }
+                // Check for filepicker status.
+                if (this.getAttribute('class').toLowerCase() == 'filepickerhidden') {
+                    var elementname = this.getAttribute('name');
+                    if (elementname && M.form_filepicker.instances[elementname].fileadded) {
+                        lock = true;
+                    } else {
+                        lock = false;
+                    }
+                } else if (this.get('nodeName').toUpperCase() === 'SELECT' && this.get('multiple') === true) {
+                    // Multiple selects can have one or more value assigned. A pipe (|) is used as a value separator
+                    // when multiple values have to be selected at the same time.
+                    values = value.split('|');
+                    selected = [];
+                    this.get('options').each(function() {
+                        if (this.get('selected')) {
+                            selected[selected.length] = this.get('value');
+                        }
+                    });
+                    if (selected.length > 0 && selected.length === values.length) {
+                        for (var i in selected) {
+                            if (values.indexOf(selected[i]) > -1) {
+                                lock = false;
+                            } else {
+                                lock = true;
+                                return;
+                            }
+                        }
+                    } else {
+                        lock = true;
+                    }
+                } else {
+                    lock = lock || this.get('value') != value;
+                }
+            });
+            return {
+                lock: lock,
+                hide: isHide ? lock : false
+            };
+        },
+        /**
+         * Is the form element an editor?
+         *
+         * @param {String} el The form element name.
+         * @return {Boolean}
+         */
+        isEditor: function(el) {
+            if (!this._editors) {
+                let editors = {};
+                const selector = '.fitem [data-fieldtype="editor"] textarea';
+                const els = this.get('form').all(selector);
+                els.each(function(node) {
+                    editors[node.getAttribute('name')] = true;
+                });
+                this._editors = editors;
+            }
+
+            return this._editors[el] || false;
+        },
+    }, {
+        NAME: 'mform-dependency-manager',
+        ATTRS: {
+            form: {
+                setter: function(value) {
+                    return Y.one('#' + value);
+                },
+                value: null
+            },
+
+            dependencies: {
+                value: {}
+            }
+        }
+    });
+
+    M.form.dependencyManager = dependencyManager;
+}
+
+/**
+ * Stores a list of the dependencyManager for each form on the page.
+ */
+M.form.dependencyManagers = {};
+
+/**
+ * Initialises a manager for a forms dependencies.
+ * This should happen once per form.
+ *
+ * @param {YUI} Y YUI3 instance
+ * @param {String} formid ID of the form
+ * @param {Array} dependencies array
+ * @return {M.form.dependencyManager}
+ */
+M.form.initFormDependencies = function(Y, formid, dependencies) {
+
+    // If the dependencies isn't an array or object we don't want to
+    // know about it
+    if (!Y.Lang.isArray(dependencies) && !Y.Lang.isObject(dependencies)) {
+        return false;
+    }
+
+    /**
+     * Fixes an issue with YUI's processing method of form.elements property
+     * in Internet Explorer.
+     *     http://yuilibrary.com/projects/yui3/ticket/2528030
+     */
+    Y.Node.ATTRS.elements = {
+        getter: function() {
+            return Y.all(new Y.Array(this._node.elements, 0, true));
+        }
+    };
+
+    M.form.dependencyManagers[formid] = new M.form.dependencyManager({form: formid, dependencies: dependencies});
+    return M.form.dependencyManagers[formid];
+};
+
+/**
+ * Update the state of a form. You need to call this after, for example, changing
+ * the state of some of the form input elements in your own code, in order that
+ * things like the disableIf state of elements can be updated.
+ *
+ * @param {String} formid ID of the form
+ */
+M.form.updateFormState = function(formid) {
+    if (formid in M.form.dependencyManagers) {
+        M.form.dependencyManagers[formid].updateAllDependencies();
+    }
+};

lib/form/grading.php

@@ -0,0 +1,173 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Advance grading form element
+ *
+ * Element-container for advanced grading custom input
+ *
+ * @package   core_form
+ * @copyright 2011 Marina Glancy
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+require_once("HTML/QuickForm/element.php");
+require_once($CFG->dirroot.'/grade/grading/form/lib.php');
+require_once('templatable_form_element.php');
+
+if (class_exists('HTML_QuickForm')) {
+    HTML_QuickForm::registerRule('gradingvalidated', 'callback', '_validate', 'MoodleQuickForm_grading');
+}
+
+/**
+ * Advance grading form element
+ *
+ * HTML class for a grading element. This is a wrapper for advanced grading plugins.
+ * When adding the 'grading' element to the form, developer must pass an object of
+ * class gradingform_instance as $attributes['gradinginstance']. Otherwise an exception will be
+ * thrown.
+ * This object is responsible for implementing functions to render element html and validate it
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2011 Marina Glancy
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_grading extends HTML_QuickForm_input implements templatable {
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+
+    /** @var string html for help button, if empty then no help */
+    var $_helpbutton='';
+
+    /** @var array Stores attributes passed to the element */
+    private $gradingattributes;
+
+    /**
+     * Class constructor
+     *
+     * @param string $elementName Input field name attribute
+     * @param mixed $elementLabel Label(s) for the input field
+     * @param mixed $attributes Either a typical HTML attribute string or an associative array
+     */
+    public function __construct($elementName=null, $elementLabel=null, $attributes=null) {
+        parent::__construct($elementName, $elementLabel, $attributes);
+        $this->_type = 'grading';
+        $this->gradingattributes = $attributes;
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_grading($elementName=null, $elementLabel=null, $attributes=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $attributes);
+    }
+
+    /**
+     * Helper function to retrieve gradingform_instance passed in element attributes
+     *
+     * @return gradingform_instance
+     */
+    public function get_gradinginstance() {
+        if (is_array($this->gradingattributes) && array_key_exists('gradinginstance', $this->gradingattributes)) {
+            return $this->gradingattributes['gradinginstance'];
+        } else {
+            return null;
+        }
+    }
+
+    /**
+     * Returns the input field in HTML
+     *
+     * @return string
+     */
+    public function toHtml(){
+        global $PAGE;
+        return $this->get_gradinginstance()->render_grading_element($PAGE, $this);
+    }
+
+    /**
+     * get html for help button
+     *
+     * @return string html for help button
+     */
+    public function getHelpButton(){
+        return $this->_helpbutton;
+    }
+
+    /**
+     * The renderer of gradingform_instance will take care itself about different display
+     * in normal and frozen states
+     *
+     * @return string
+     */
+    public function getElementTemplateType(){
+        return 'default';
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element.
+     * Adds necessary rules to the element and checks that coorenct instance of gradingform_instance
+     * is passed in attributes
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return bool
+     * @throws moodle_exception
+     */
+    public function onQuickFormEvent($event, $arg, &$caller) {
+        if ($event == 'createElement') {
+            $attributes = $arg[2];
+            if (!is_array($attributes) || !array_key_exists('gradinginstance', $attributes) || !($attributes['gradinginstance'] instanceof gradingform_instance)) {
+                throw new moodle_exception('exc_gradingformelement', 'grading');
+            }
+        }
+
+        $name = $this->getName();
+        if ($name && $caller->elementExists($name)) {
+            $caller->addRule($name, $this->get_gradinginstance()->default_validation_error_message(), 'gradingvalidated', $this->gradingattributes);
+        }
+        return parent::onQuickFormEvent($event, $arg, $caller);
+    }
+
+    /**
+     * Function registered as rule for this element and is called when this element is being validated.
+     * This is a wrapper to pass the validation to the method gradingform_instance::validate_grading_element
+     *
+     * @param mixed $elementvalue value of element to be validated
+     * @param array $attributes element attributes
+     * @return MoodleQuickForm_grading
+     */
+    public static function _validate($elementvalue, $attributes = null) {
+        if (!$attributes['gradinginstance']->is_empty_form($elementvalue)) {
+            return $attributes['gradinginstance']->validate_grading_element($elementvalue);
+        }
+        return true;
+    }
+
+    public function export_for_template(renderer_base $output) {
+        $context = $this->export_for_template_base($output);
+        $context['html'] = $this->toHtml();
+        return $context;
+    }
+}

lib/form/group.php

@@ -0,0 +1,310 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Form element group
+ *
+ * Contains HTML class for group form element
+ *
+ * @package   core_form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once("HTML/QuickForm/group.php");
+require_once('templatable_form_element.php');
+
+/**
+ * HTML class for a form element group
+ *
+ * Overloaded {@link HTML_QuickForm_group} with default behavior modified for Moodle.
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_group extends HTML_QuickForm_group implements templatable {
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+
+    /** @var string html for help button, if empty then no help */
+    var $_helpbutton='';
+
+    /** @var bool if true label will be hidden. */
+    protected $_hiddenLabel = false;
+
+    /** @var MoodleQuickForm */
+    protected $_mform = null;
+
+    protected $_renderedfromtemplate = false;
+
+    /**
+     * constructor
+     *
+     * @param string $elementName (optional) name of the group
+     * @param string $elementLabel (optional) group label
+     * @param array $elements (optional) array of HTML_QuickForm_element elements to group
+     * @param string|array $separator (optional) Use a string for one separator, or use an array to alternate the separators
+     * @param string $appendName (optional) string to appened to grouped elements.
+     * @param mixed $attributes (optional) Either a typical HTML attribute string
+     *              or an associative array
+     */
+    public function __construct(
+        $elementName = null,
+        $elementLabel = null,
+        $elements = null,
+        $separator = null,
+        $appendName = true,
+        $attributes = null
+    ) {
+        parent::__construct($elementName, $elementLabel, $elements, $separator, $appendName, $attributes);
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_group($elementName=null, $elementLabel=null, $elements=null, $separator=null, $appendName = true) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $elements, $separator, $appendName);
+    }
+
+    /** @var string template type, would cause problems with client side validation so will leave for now */
+    //var $_elementTemplateType='fieldset';
+
+    /**
+     * set html for help button
+     */
+    function getHelpButton(){
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Returns element template, nodisplay/static/fieldset
+     *
+     * @return string
+     */
+    function getElementTemplateType(){
+        if ($this->_flagFrozen){
+            if ($this->getGroupType() == 'submit'){
+                return 'nodisplay';
+            } else {
+                return 'static';
+            }
+        } else {
+            if ($this->getGroupType() == 'submit') {
+                return 'actionbuttons';
+            }
+            return 'fieldset';
+        }
+    }
+
+    /**
+     * Sets label to be hidden
+     *
+     * @param bool $hiddenLabel sets if label should be hidden
+     */
+    public function setHiddenLabel($hiddenLabel) {
+        $this->_hiddenLabel = $hiddenLabel;
+    }
+
+    /**
+     * Sets the grouped elements and hides label
+     *
+     * @param array $elements
+     */
+    function setElements($elements){
+        parent::setElements($elements);
+        foreach ($this->_elements as $element){
+            if (method_exists($element, 'setHiddenLabel')){
+                $element->setHiddenLabel(true);
+            }
+        }
+    }
+
+    /**
+     * Stores the form this element was added to
+     * This object is later used by {@link MoodleQuickForm_group::createElement()}
+     * @param null|MoodleQuickForm $mform
+     */
+    public function setMoodleForm($mform) {
+        if ($mform && $mform instanceof MoodleQuickForm) {
+            $this->_mform = $mform;
+        }
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * If this function is overridden and parent is not called the element must be responsible for
+     * storing the MoodleQuickForm object, see {@link MoodleQuickForm_group::setMoodleForm()}
+     *
+     * @param     string $event Name of event
+     * @param     mixed $arg event arguments
+     * @param     mixed $caller calling object
+     * @return    ?bool
+     */
+    public function onQuickFormEvent($event, $arg, &$caller) {
+        $this->setMoodleForm($caller);
+        return parent::onQuickFormEvent($event, $arg, $caller);
+    }
+
+    /**
+     * Creates an element to add to the group
+     * Expects the same arguments as MoodleQuickForm::createElement()
+     */
+    public function createFormElement() {
+        if (!$this->_mform) {
+            throw new coding_exception('You can not call createFormElement() on the group element that was not yet added to a form.');
+        }
+        return call_user_func_array([$this->_mform, 'createElement'], func_get_args());
+    }
+
+    /**
+     * Return attributes suitable for passing to {@see createFormElement}, comprised of all group attributes without ID in
+     * order to ensure uniqueness of that value within the group
+     *
+     * @return array
+     */
+    public function getAttributesForFormElement(): array {
+        return array_diff_key((array) $this->getAttributes(), array_flip(['id']));
+    }
+
+    public function export_for_template(renderer_base $output) {
+        global $OUTPUT;
+
+        $context = $this->export_for_template_base($output);
+
+        $this->_renderedfromtemplate = true;
+
+        include_once('HTML/QuickForm/Renderer/Default.php');
+
+        $elements = [];
+        $name = $this->getName();
+        $i = 0;
+        foreach ($this->_elements as $key => $element) {
+            $elementname = '';
+            if ($this->_appendName) {
+                $elementname = $element->getName();
+                if (isset($elementname)) {
+                    $element->setName($name . '['. (strlen($elementname) ? $elementname : $key) .']');
+                } else {
+                    $element->setName($name);
+                }
+            }
+            $element->_generateId();
+
+            $out = $OUTPUT->mform_element($element, false, false, '', true);
+
+            if (empty($out)) {
+                $renderer = new HTML_QuickForm_Renderer_Default();
+                $renderer->setElementTemplate('{element}');
+                $element->accept($renderer);
+                $out = $renderer->toHtml();
+            }
+
+            // Replicates the separator logic from 'pear/HTML/QuickForm/Renderer/Default.php'.
+            $separator = '';
+            if ($i > 0) {
+                if (is_array($this->_separator)) {
+                    $separator = $this->_separator[($i - 1) % count($this->_separator)];
+                } else if ($this->_separator === null) {
+                    $separator = '&nbsp;';
+                } else {
+                    $separator = (string) $this->_separator;
+                }
+            }
+
+            $elements[] = [
+                'separator' => $separator,
+                'html' => $out
+            ];
+
+            // Restore the element's name.
+            if ($this->_appendName) {
+                $element->setName($elementname);
+            }
+
+            $i++;
+        }
+
+        $context['groupname'] = $name;
+        $context['elements'] = $elements;
+        return $context;
+    }
+
+    /**
+     * Accepts a renderer
+     *
+     * @param object     An HTML_QuickForm_Renderer object
+     * @param bool       Whether a group is required
+     * @param string     An error message associated with a group
+     * @access public
+     * @return void
+     */
+    public function accept(&$renderer, $required = false, $error = null) {
+        $this->_createElementsIfNotExist();
+        $renderer->startGroup($this, $required, $error);
+        if (!$this->_renderedfromtemplate) {
+            // Backwards compatible path - only do this if we didn't render the sub-elements already.
+            $name = $this->getName();
+            foreach (array_keys($this->_elements) as $key) {
+                $element =& $this->_elements[$key];
+                $elementname = '';
+                if ($this->_appendName) {
+                    $elementname = $element->getName();
+                    if (isset($elementname)) {
+                        $element->setName($name . '['. (strlen($elementname) ? $elementname : $key) .']');
+                    } else {
+                        $element->setName($name);
+                    }
+                }
+
+                $required = !$element->isFrozen() && in_array($element->getName(), $this->_required);
+
+                $element->accept($renderer, $required);
+
+                // Restore the element's name.
+                if ($this->_appendName) {
+                    $element->setName($elementname);
+                }
+            }
+        }
+        $renderer->finishGroup($this);
+    }
+
+    /**
+     * Calls the validateSubmitValue function for the containing elements and returns an error string as soon as it finds one.
+     *
+     * @param array $values Values of the containing elements.
+     * @return string|null Validation error message or null.
+     */
+    public function validateSubmitValue($values) {
+        foreach ($this->_elements as $element) {
+            if (method_exists($element, 'validateSubmitValue')) {
+                $value = $values[$element->getName()] ?? null;
+                $result = $element->validateSubmitValue($value);
+                if (!empty($result) && is_string($result)) {
+                    return $result;
+                }
+            }
+        }
+    }
+}

lib/form/header.php

@@ -0,0 +1,83 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Header form element
+ *
+ * Contains a pseudo-element used for adding headers to form
+ *
+ * @package   core_form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once 'HTML/QuickForm/header.php';
+
+/**
+ * Header form element
+ *
+ * A pseudo-element used for adding headers to form
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_header extends HTML_QuickForm_header
+{
+    /** @var string html for help button, if empty then no help */
+    var $_helpbutton='';
+
+    /**
+     * constructor
+     *
+     * @param string $elementName name of the header element
+     * @param string $text text displayed in header element
+     */
+    public function __construct($elementName = null, $text = null) {
+        parent::__construct($elementName, $text);
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_header($elementName = null, $text = null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $text);
+    }
+
+   /**
+    * Accepts a renderer
+    *
+    * @param HTML_QuickForm_Renderer $renderer a HTML_QuickForm_Renderer object
+    */
+    function accept(&$renderer, $required=false, $error=null)
+    {
+        $renderer->renderHeader($this);
+    }
+
+    /**
+     * get html for help button
+     *
+     * @return string html for help button
+     */
+    function getHelpButton(){
+        return $this->_helpbutton;
+    }
+}

lib/form/hidden.php

@@ -0,0 +1,81 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Hidden type form element
+ *
+ * Contains HTML class for a hidden type element
+ *
+ * @package   core_form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once('HTML/QuickForm/hidden.php');
+
+/**
+ * Hidden type form element
+ *
+ * HTML class for a hidden type element
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_hidden extends HTML_QuickForm_hidden{
+    /** @var string html for help button, if empty then no help */
+    var $_helpbutton='';
+
+    /**
+     * Constructor
+     *
+     * @param string $elementName (optional) name of the hidden element
+     * @param string $value (optional) value of the element
+     * @param mixed  $attributes (optional) Either a typical HTML attribute string
+     *               or an associative array
+     */
+    public function __construct($elementName=null, $value='', $attributes=null) {
+        parent::__construct($elementName, $value, $attributes);
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_hidden($elementName=null, $value='', $attributes=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        return self::__construct($elementName, $value, $attributes);
+    }
+
+    /**
+     * @deprecated since Moodle 2.0
+     */
+    function setHelpButton($helpbuttonargs, $function='helpbutton'){
+        throw new coding_exception('setHelpButton() can not be used any more, please see MoodleQuickForm::addHelpButton().');
+    }
+
+    /**
+     * get html for help button
+     *
+     * @return string html for help button
+     */
+    function getHelpButton(){
+        return '';
+    }
+}

lib/form/listing.php

@@ -0,0 +1,161 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Listing form element.
+ *
+ * Contains HTML class for a listing form element.
+ *
+ * @package   core_form
+ * @copyright 2012 Jerome Mouneyrac
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+if (!defined('MOODLE_INTERNAL')) {
+    die('Direct access to this script is forbidden.');
+}
+
+require_once("HTML/QuickForm/input.php");
+
+/**
+* The listing element is a simple customizable "select" without the input type=select.
+* One main div contains the "large" html of an item.
+* A show/hide div shows a hidden div containing the list of all items.
+* This list is composed by the "small" html of each item.
+*
+* How to use it:
+* The options parameter is an array containing:
+*   - items => array of object: the key is the value of the form input
+*                               $item->rowhtml => small html
+*                               $item->mainhtml => large html
+*   - showall/hideall => string for the Show/Hide button
+*
+* WARNINGS: The form lets you display HTML. So it is subject to CROSS-SCRIPTING if you send it uncleaned HTML.
+*           Don't forget to escape your HTML as soon as one string comes from an input/external source.
+*
+* How to customize it:
+*   You can change the css in core.css. For example if you remove float:left; from .formlistingrow,
+*   then the item list is not display as tabs but as rows.
+*
+* @package   core_form
+* @copyright 2012 Jerome Mouneyrac
+* @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+*/
+class MoodleQuickForm_listing extends HTML_QuickForm_input {
+
+    /** @var array items to display. */
+    protected $items = array();
+
+    /** @var string language string for Show All. */
+    protected $showall;
+
+    /** @var string language string for Hide. */
+    protected $hideall;
+
+    /**
+     * Constructor.
+     *
+     * @param string $elementName (optional) name of the listing.
+     * @param string $elementLabel (optional) listing label.
+     * @param array $attributes (optional) Either a typical HTML attribute string or an associative array.
+     * @param array $options set of options to initalize listing.
+     */
+    public function __construct($elementName=null, $elementLabel=null, $attributes=null, $options=array()) {
+
+       $this->_type = 'listing';
+        if (!empty($options['items'])) {
+            $this->items = $options['items'];
+        }
+        if (!empty($options['showall'])) {
+            $this->showall = $options['showall'];
+        } else {
+            $this->showall = get_string('showall');
+        }
+        if (!empty($options['hideall'])) {
+            $this->hideall = $options['hideall'];
+        } else {
+            $this->hideall = get_string('hide');
+        }
+        parent::__construct($elementName, $elementLabel, $attributes);
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_listing($elementName=null, $elementLabel=null, $attributes=null, $options=array()) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $attributes, $options);
+    }
+
+    /**
+     * Returns HTML for listing form element.
+     *
+     * @return string the HTML.
+     */
+    function toHtml() {
+        global $CFG, $PAGE;
+
+        $this->_generateId();
+        $elementid = $this->getAttribute('id');
+        $mainhtml = html_writer::tag('div', $this->items[$this->getValue()]->mainhtml,
+                array('id' => $elementid . '_items_main', 'class' => 'formlistingmain'));
+
+        // Add the main div containing the selected item (+ the caption: "More items").
+        $html = html_writer::tag('div', $mainhtml .
+                    html_writer::tag('div', $this->showall,
+                        array('id' => $elementid . '_items_caption', 'class' => 'formlistingmore')),
+                    array('id' => $elementid . '_items', 'class' => 'formlisting hide'));
+
+        // Add collapsible region: all the items.
+        $itemrows = '';
+        $html .= html_writer::tag('div', $itemrows,
+                array('id' => $elementid . '_items_all', 'class' => 'formlistingall'));
+
+        // Add radio buttons for non javascript support.
+        $radiobuttons = '';
+        foreach ($this->items as $itemid => $item) {
+            $radioparams = array('name' => $this->getName(), 'value' => $itemid,
+                    'id' => 'id_'.$itemid, 'class' => 'formlistinginputradio', 'type' => 'radio');
+            if ($itemid == $this->getValue()) {
+                $radioparams['checked'] = 'checked';
+            }
+            $radiobuttons .= html_writer::tag('div', html_writer::tag('input',
+                html_writer::tag('div', $item->rowhtml, array('class' => 'formlistingradiocontent')), $radioparams),
+                array('class' => 'formlistingradio'));
+        }
+
+        // Container for the hidden hidden input which will contain the selected item.
+        $html .= html_writer::tag('div', $radiobuttons,
+                array('id' => 'formlistinginputcontainer_' . $elementid, 'class' => 'formlistinginputcontainer'));
+
+        $module = array('name'=>'form_listing', 'fullpath'=>'/lib/form/yui/listing/listing.js',
+            'requires'=>array('node', 'event', 'transition', 'escape'));
+
+        $PAGE->requires->js_init_call('M.form_listing.init',
+                 array(array(
+                'elementid' => $elementid.'_items',
+                'hideall' => $this->hideall,
+                'showall' => $this->showall,
+                'hiddeninputid' => $this->getAttribute('id'),
+                'items' => $this->items,
+                'inputname' => $elementid,
+                'currentvalue' => $this->getValue())), true, $module);
+
+        return $html;
+    }
+}

lib/form/modgrade.php

@@ -0,0 +1,551 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Drop down form element to select the grade
+ *
+ * Contains HTML class for a drop down element to select the grade for an activity,
+ * used in mod update form
+ *
+ * @package   core_form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+require_once "$CFG->libdir/form/select.php";
+require_once("HTML/QuickForm/element.php");
+require_once($CFG->dirroot.'/lib/form/group.php');
+require_once($CFG->dirroot.'/lib/grade/grade_scale.php');
+
+/**
+ * Drop down form element to select the grade
+ *
+ * HTML class for a drop down element to select the grade for an activity,
+ * used in mod update form
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_modgrade extends MoodleQuickForm_group {
+
+    /** @var boolean $isupdate Is this an add or an update ? */
+    public $isupdate = false;
+
+    /** @var float $currentgrade The current grademax for the grade_item */
+    public $currentgrade = false;
+
+    /** @var boolean $hasgrades Has this grade_item got any real grades (with values) */
+    public $hasgrades = false;
+
+    /** @var boolean $canrescale Does this activity support rescaling grades? */
+    public $canrescale = false;
+
+    /** @var int $currentscaleid The current scale id */
+    public $currentscaleid = null;
+
+    /** @var string $currentgradetype The current gradetype - can either be 'none', 'scale', or 'point' */
+    public $currentgradetype = 'none';
+
+    /** @var boolean $useratings Set to true if the activity is using ratings, false otherwise */
+    public $useratings = false;
+
+    /** @var MoodleQuickForm_select $gradetypeformelement */
+    private $gradetypeformelement;
+
+    /** @var MoodleQuickForm_select $scaleformelement */
+    private $scaleformelement;
+
+    /** @var MoodleQuickForm_text $maxgradeformelement */
+    private $maxgradeformelement;
+
+    /**
+     * Constructor
+     *
+     * @param string $elementname Element's name
+     * @param mixed $elementlabel Label(s) for an element
+     * @param array $options Options to control the element's display. Required - must contain the following options:
+     *              'isupdate' - is this a new module or are we editing an existing one?
+     *              'currentgrade' - the current grademax in the database for this gradeitem
+     *              'hasgrades' - whether or not the grade_item has existing grade_grades
+     *              'canrescale' - whether or not the activity supports rescaling grades
+     * @param mixed $attributes Either a typical HTML attribute string or an associative array
+     */
+    public function __construct($elementname = null, $elementlabel = null, $options = array(), $attributes = null) {
+        // TODO MDL-52313 Replace with the call to parent::__construct().
+        HTML_QuickForm_element::__construct($elementname, $elementlabel, $attributes);
+        $this->_persistantFreeze = true;
+        $this->_appendName = true;
+        $this->_type = 'modgrade';
+        $this->isupdate = !empty($options['isupdate']);
+        if (isset($options['currentgrade'])) {
+            $this->currentgrade = $options['currentgrade'];
+        }
+        if (isset($options['currentgradetype'])) {
+            $gradetype = $options['currentgradetype'];
+            switch ($gradetype) {
+                case GRADE_TYPE_NONE :
+                    $this->currentgradetype = 'none';
+                    break;
+                case GRADE_TYPE_SCALE :
+                    $this->currentgradetype = 'scale';
+                    break;
+                case GRADE_TYPE_VALUE :
+                    $this->currentgradetype = 'point';
+                    break;
+            }
+        }
+        if (isset($options['currentscaleid'])) {
+            $this->currentscaleid = $options['currentscaleid'];
+        }
+        $this->hasgrades = !empty($options['hasgrades']);
+        $this->canrescale = !empty($options['canrescale']);
+        $this->useratings = !empty($options['useratings']);
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_modgrade($elementname = null, $elementlabel = null, $options = array(), $attributes = null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementname, $elementlabel, $options, $attributes);
+    }
+
+    /**
+     * Create elements for this group.
+     */
+    public function _createElements() {
+        global $COURSE, $CFG, $OUTPUT;
+        $attributes = $this->getAttributes();
+        if (is_null($attributes)) {
+            $attributes = array();
+        }
+
+        $this->_elements = array();
+
+        // Create main elements
+        // We have to create the scale and point elements first, as we need their IDs.
+
+        // Grade scale select box.
+        $scales = get_scales_menu($COURSE->id);
+        $langscale = get_string('modgradetypescale', 'grades');
+        $this->scaleformelement = $this->createFormElement('select', 'modgrade_scale', $langscale,
+            $scales, $attributes);
+        $this->scaleformelement->setHiddenLabel(true);
+        $scaleformelementid = $this->generate_modgrade_subelement_id('modgrade_scale');
+        $this->scaleformelement->updateAttributes(array('id' => $scaleformelementid));
+
+        // Maximum grade textbox.
+        $langmaxgrade = get_string('modgrademaxgrade', 'grades');
+        $this->maxgradeformelement = $this->createFormElement('text', 'modgrade_point', $langmaxgrade, array());
+        $this->maxgradeformelement->setHiddenLabel(true);
+        $maxgradeformelementid = $this->generate_modgrade_subelement_id('modgrade_point');
+        $this->maxgradeformelement->updateAttributes(array('id' => $maxgradeformelementid));
+
+        // Grade type select box.
+        $gradetype = array(
+            'none' => get_string('modgradetypenone', 'grades'),
+            'scale' => get_string('modgradetypescale', 'grades'),
+            'point' => get_string('modgradetypepoint', 'grades'),
+        );
+        $langtype = get_string('modgradetype', 'grades');
+        $this->gradetypeformelement = $this->createFormElement('select', 'modgrade_type', $langtype, $gradetype,
+            $attributes, true);
+        $this->gradetypeformelement->setHiddenLabel(true);
+        $gradetypeformelementid = $this->generate_modgrade_subelement_id('modgrade_type');
+        $this->gradetypeformelement->updateAttributes(array('id' => $gradetypeformelementid));
+
+        if ($this->isupdate && $this->hasgrades) {
+            $this->gradetypeformelement->updateAttributes(array('disabled' => 'disabled'));
+            $this->scaleformelement->updateAttributes(array('disabled' => 'disabled'));
+
+            // Check box for options for processing existing grades.
+            if ($this->canrescale) {
+                $langrescalegrades = get_string('modgraderescalegrades', 'grades');
+                $choices = array();
+                $choices[''] = get_string('choose');
+                $choices['no'] = get_string('no');
+                $choices['yes'] = get_string('yes');
+                $rescalegradesselect = $this->createFormElement('select',
+                    'modgrade_rescalegrades',
+                    $langrescalegrades,
+                    $choices);
+                $rescalegradesselect->setHiddenLabel(true);
+                $rescalegradesselectid = $this->generate_modgrade_subelement_id('modgrade_rescalegrades');
+                $rescalegradesselect->updateAttributes(array('id' => $rescalegradesselectid));
+            }
+        }
+
+        // Add elements.
+        if ($this->isupdate && $this->hasgrades) {
+            // Set a message so the user knows why they can not alter the grade type or scale.
+            if ($this->currentgradetype == 'scale') {
+                $gradesexistmsg = get_string('modgradecantchangegradetyporscalemsg', 'grades');
+            } else if ($this->canrescale) {
+                $gradesexistmsg = get_string('modgradecantchangegradetypemsg', 'grades');
+            } else {
+                $gradesexistmsg = get_string('modgradecantchangegradetype', 'grades');
+            }
+
+            $gradesexisthtml = '<div class=\'alert alert-warning\'>' . $gradesexistmsg . '</div>';
+            $this->_elements[] = $this->createFormElement('static', 'gradesexistmsg', '', $gradesexisthtml);
+        }
+
+        // Grade type select box.
+        $label = html_writer::tag('label', $this->gradetypeformelement->getLabel(),
+            array('for' => $this->gradetypeformelement->getAttribute('id')));
+        $this->_elements[] = $this->createFormElement('static', 'gradetypelabel', '', '&nbsp;'.$label);
+        $this->_elements[] = $this->gradetypeformelement;
+        $this->_elements[] = $this->createFormElement('static', 'gradetypespacer', '', '<br />');
+
+        // Only show the grade scale select box when applicable.
+        if (!$this->isupdate || !$this->hasgrades || $this->currentgradetype == 'scale') {
+            $label = html_writer::tag('label', $this->scaleformelement->getLabel(),
+                array('for' => $this->scaleformelement->getAttribute('id')));
+            $this->_elements[] = $this->createFormElement('static', 'scalelabel', '', $label);
+            $this->_elements[] = $this->scaleformelement;
+            $this->_elements[] = $this->createFormElement('static', 'scalespacer', '', '<br />');
+        }
+
+        if ($this->isupdate && $this->hasgrades && $this->canrescale && $this->currentgradetype == 'point') {
+            // We need to know how to apply any changes to maxgrade - ie to either update, or don't touch exising grades.
+            $label = html_writer::tag('label', $rescalegradesselect->getLabel(),
+                array('for' => $rescalegradesselect->getAttribute('id')));
+            $labelhelp = new help_icon('modgraderescalegrades', 'grades');
+            $this->_elements[] = $this->createFormElement('static', 'scalelabel', '', $label . $OUTPUT->render($labelhelp));
+            $this->_elements[] = $rescalegradesselect;
+            $this->_elements[] = $this->createFormElement('static', 'scalespacer', '', '<br />');
+        }
+
+        // Only show the max points form element when applicable.
+        if (!$this->isupdate || !$this->hasgrades || $this->currentgradetype == 'point') {
+            $label = html_writer::tag('label', $this->maxgradeformelement->getLabel(),
+                array('for' => $this->maxgradeformelement->getAttribute('id')));
+            $this->_elements[] = $this->createFormElement('static', 'pointlabel', '', $label);
+
+            // Check if there are grades and if so then disable maxgradeformelement.
+            if ($this->hasgrades) {
+                // If it has grades then disable it.
+                $this->maxgradeformelement->updateAttributes(['disabled' => 'disabled']);
+            }
+
+            $this->_elements[] = $this->maxgradeformelement;
+            $this->_elements[] = $this->createFormElement('static', 'pointspacer', '', '<br />');
+        }
+    }
+
+    /**
+     * Calculate the output value for the element as a whole.
+     *
+     * @param array $submitvalues The incoming values from the form.
+     * @param bool $notused Not used.
+     * @return array Return value for the element, formatted like field name => value.
+     */
+    public function exportValue(&$submitvalues, $notused = false) {
+        global $COURSE;
+
+        // Get the values from all the child elements.
+        $vals = array();
+        foreach ($this->_elements as $element) {
+            $thisexport = $element->exportValue($submitvalues[$this->getName()], true);
+            if (!is_null($thisexport)) {
+                $vals += $thisexport;
+            }
+        }
+
+        $type = (isset($vals['modgrade_type'])) ? $vals['modgrade_type'] : 'none';
+        $point = (isset($vals['modgrade_point'])) ? $vals['modgrade_point'] : null;
+        $scale = (isset($vals['modgrade_scale'])) ? $vals['modgrade_scale'] : null;
+        $rescalegrades = (isset($vals['modgrade_rescalegrades'])) ? $vals['modgrade_rescalegrades'] : null;
+
+        $return = $this->process_value($type, $scale, $point, $rescalegrades);
+        return array($this->getName() => $return, $this->getName() . '_rescalegrades' => $rescalegrades);
+    }
+
+    /**
+     * Process the value for the group based on the selected grade type, and the input for the scale and point elements.
+     *
+     * @param  string $type The value of the grade type select box. Can be 'none', 'scale', or 'point'
+     * @param  string|int $scale The value of the scale select box.
+     * @param  string|int $point The value of the point grade textbox.
+     * @param  string $rescalegrades The value of the rescalegrades select.
+     * @return int The resulting value
+     */
+    protected function process_value($type='none', $scale=null, $point=null, $rescalegrades=null) {
+        global $COURSE;
+        $val = 0;
+
+        // If the maxgrade field is disabled with javascript, no value is sent with the form and mform assumes the default.
+        if ($this->isupdate && $this->hasgrades && $this->currentgradetype == 'point') {
+            // If the user cannot rescale, then return the original.
+            $returnoriginal = !$this->canrescale;
+
+            // If the user was forced to choose a rescale option - and they haven't - prevent any changes to the max grade.
+            $returnoriginal = $returnoriginal || ($this->canrescale && empty($rescalegrades));
+
+            if ($returnoriginal) {
+                return (string)unformat_float($this->currentgrade);
+            }
+        }
+        switch ($type) {
+            case 'point':
+                if ($this->validate_point($point) === true) {
+                    $val = (int)$point;
+                }
+                break;
+
+            case 'scale':
+                if ($this->validate_scale($scale)) {
+                    $val = (int)(-$scale);
+                }
+                break;
+        }
+        return $val;
+    }
+
+    /**
+     * Determines whether a given value is a valid scale selection.
+     *
+     * @param string|int $val The value to test.
+     * @return bool Valid or invalid
+     */
+    protected function validate_scale($val) {
+        global $COURSE;
+        $scales = get_scales_menu($COURSE->id);
+        return (!empty($val) && isset($scales[(int)$val])) ? true : false;
+    }
+
+    /**
+     * Determines whether a given value is a valid point selection.
+     *
+     * @param string|int $val The value to test.
+     * @return bool Valid or invalid
+     */
+    protected function validate_point($val) {
+        if (empty($val)) {
+            return false;
+        }
+        $maxgrade = (int)get_config('core', 'gradepointmax');
+        $isintlike = ((string)(int)$val === $val) ? true : false;
+        return ($isintlike === true && $val > 0 && $val <= $maxgrade) ? true : false;
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element.
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param MoodleQuickForm $caller calling object
+     * @return mixed
+     */
+    public function onQuickFormEvent($event, $arg, &$caller) {
+        $this->setMoodleForm($caller);
+        switch ($event) {
+            case 'createElement':
+                // The first argument is the name.
+                $name = $arg[0];
+
+                // Set disable actions.
+                $caller->hideIf($name.'[modgrade_scale]', $name.'[modgrade_type]', 'neq', 'scale');
+                $caller->hideIf($name.'[modgrade_point]', $name.'[modgrade_type]', 'neq', 'point');
+                $caller->hideIf($name.'[modgrade_rescalegrades]', $name.'[modgrade_type]', 'neq', 'point');
+
+                // Set validation rules for the sub-elements belonging to this element.
+                // A handy note: the parent scope of a closure is the function in which the closure was declared.
+                // Because of this using $this is safe despite the closures being called statically.
+                // A nasty magic hack!
+                $checkgradetypechange = function($val) {
+                    // Nothing is affected by changes to the grade type if there are no grades yet.
+                    if (!$this->hasgrades) {
+                        return true;
+                    }
+                    // Check if we are changing the grade type when grades are present.
+                    if (isset($val['modgrade_type']) && $val['modgrade_type'] !== $this->currentgradetype) {
+                        return false;
+                    }
+                    return true;
+                };
+                $checkscalechange = function($val) {
+                    // Nothing is affected by changes to the scale if there are no grades yet.
+                    if (!$this->hasgrades) {
+                        return true;
+                    }
+                    // Check if we are changing the scale type when grades are present.
+                    // If modgrade_type is empty then use currentgradetype.
+                    $gradetype = isset($val['modgrade_type']) ? $val['modgrade_type'] : $this->currentgradetype;
+                    if ($gradetype === 'scale') {
+                        if (isset($val['modgrade_scale']) && ($val['modgrade_scale'] !== $this->currentscaleid)) {
+                            return false;
+                        }
+                    }
+                    return true;
+                };
+                $checkmaxgradechange = function($val) {
+                    // Nothing is affected by changes to the max grade if there are no grades yet.
+                    if (!$this->hasgrades) {
+                        return true;
+                    }
+                    // If we are not using ratings we can change the max grade.
+                    if (!$this->useratings) {
+                        return true;
+                    }
+                    // Check if we are changing the max grade if we are using ratings and there is a grade.
+                    // If modgrade_type is empty then use currentgradetype.
+                    $gradetype = isset($val['modgrade_type']) ? $val['modgrade_type'] : $this->currentgradetype;
+                    if ($gradetype === 'point') {
+                        if (isset($val['modgrade_point']) &&
+                            grade_floats_different($this->currentgrade, $val['modgrade_point'])) {
+                            return false;
+                        }
+                    }
+                    return true;
+                };
+                $checkmaxgrade = function($val) {
+                    // Closure to validate a max points value. See the note above about scope if this confuses you.
+                    // If modgrade_type is empty then use currentgradetype.
+                    $gradetype = isset($val['modgrade_type']) ? $val['modgrade_type'] : $this->currentgradetype;
+                    if ($gradetype === 'point') {
+                        if (isset($val['modgrade_point'])) {
+                            return $this->validate_point($val['modgrade_point']);
+                        }
+                    }
+                    return true;
+                };
+                $checkvalidscale = function($val) {
+                    // Closure to validate a scale value. See the note above about scope if this confuses you.
+                    // If modgrade_type is empty then use currentgradetype.
+                    $gradetype = isset($val['modgrade_type']) ? $val['modgrade_type'] : $this->currentgradetype;
+                    if ($gradetype === 'scale') {
+                        if (isset($val['modgrade_scale'])) {
+                            return $this->validate_scale($val['modgrade_scale']);
+                        }
+                    }
+                    return true;
+                };
+
+                $checkrescale = function($val) {
+                    // Nothing is affected by changes to grademax if there are no grades yet.
+                    if (!$this->isupdate || !$this->hasgrades || !$this->canrescale) {
+                        return true;
+                    }
+                    // Closure to validate a scale value. See the note above about scope if this confuses you.
+                    // If modgrade_type is empty then use currentgradetype.
+                    $gradetype = isset($val['modgrade_type']) ? $val['modgrade_type'] : $this->currentgradetype;
+                    if ($gradetype === 'point' && isset($val['modgrade_point'])) {
+                        // Work out if the value was actually changed in the form.
+                        if (grade_floats_different($this->currentgrade, $val['modgrade_point'])) {
+                            if (empty($val['modgrade_rescalegrades'])) {
+                                // This was an "edit", the grademax was changed and the process existing setting was not set.
+                                return false;
+                            }
+                        }
+                    }
+                    return true;
+                };
+
+                $cantchangegradetype = get_string('modgradecantchangegradetype', 'grades');
+                $cantchangemaxgrade = get_string('modgradecantchangeratingmaxgrade', 'grades');
+                $maxgradeexceeded = get_string('modgradeerrorbadpoint', 'grades', get_config('core', 'gradepointmax'));
+                $invalidscale = get_string('modgradeerrorbadscale', 'grades');
+                $cantchangescale = get_string('modgradecantchangescale', 'grades');
+                $mustchooserescale = get_string('mustchooserescaleyesorno', 'grades');
+                // When creating the rules the sixth arg is $force, we set it to true because otherwise the form
+                // will attempt to validate the existence of the element, we don't want this because the element
+                // is being created right now and doesn't actually exist as a registered element yet.
+                $caller->addRule($name, $cantchangegradetype, 'callback', $checkgradetypechange, 'server', false, true);
+                $caller->addRule($name, $cantchangemaxgrade, 'callback', $checkmaxgradechange, 'server', false, true);
+                $caller->addRule($name, $maxgradeexceeded, 'callback', $checkmaxgrade, 'server', false, true);
+                $caller->addRule($name, $invalidscale, 'callback', $checkvalidscale, 'server', false, true);
+                $caller->addRule($name, $cantchangescale, 'callback', $checkscalechange, 'server', false, true);
+                $caller->addRule($name, $mustchooserescale, 'callback', $checkrescale, 'server', false, true);
+
+                break;
+
+            case 'updateValue':
+                // As this is a group element with no value of its own we are only interested in situations where the
+                // default value or a constant value are being provided to the actual element.
+                // In this case we expect an int that is going to translate to a scale if negative, or to max points
+                // if positive.
+
+                // Set the maximum points field to disabled if the rescale option has not been chosen and there are grades.
+                $caller->disabledIf($this->getName() . '[modgrade_point]', $this->getName() .
+                        '[modgrade_rescalegrades]', 'eq', '');
+
+                // A constant value should be given as an int.
+                // The default value should be an int and be either $CFG->gradepointdefault or whatever was set in set_data().
+                $value = $this->_findValue($caller->_constantValues);
+                if (null === $value) {
+                    if ($caller->isSubmitted() && $this->_findValue($caller->_submitValues) !== null) {
+                        // Submitted values are array, one value for each individual element in this group.
+                        // When there is submitted data let parent::onQuickFormEvent() process it.
+                        break;
+                    }
+                    $value = $this->_findValue($caller->_defaultValues);
+                }
+
+                if (!is_null($value) && !is_scalar($value)) {
+                    // Something unexpected (likely an array of subelement values) has been given - this will be dealt
+                    // with somewhere else - where exactly... likely the subelements.
+                    debugging('An invalid value (type '.gettype($value).') has arrived at '.__METHOD__, DEBUG_DEVELOPER);
+                    break;
+                }
+
+                // Set element state for existing data.
+                // This is really a pretty hacky thing to do, when data is being set the group element is called
+                // with the data first and the subelements called afterwards.
+                // This means that the subelements data (inc const and default values) can be overridden by form code.
+                // So - when we call this code really we can't be sure that will be the end value for the element.
+                if (!empty($this->_elements)) {
+                    if (!empty($value)) {
+                        if ($value < 0) {
+                            $this->gradetypeformelement->setValue('scale');
+                            $this->scaleformelement->setValue(($value * -1));
+                        } else if ($value > 0) {
+                            $this->gradetypeformelement->setValue('point');
+                            $maxvalue = !empty($this->currentgrade) ? (string)unformat_float($this->currentgrade) : $value;
+                            $this->maxgradeformelement->setValue($maxvalue);
+                        }
+                    } else {
+                        $this->gradetypeformelement->setValue('none');
+                        $this->maxgradeformelement->setValue(100);
+                    }
+                }
+                break;
+        }
+
+        // Always let the parent do its thing!
+        return parent::onQuickFormEvent($event, $arg, $caller);
+    }
+
+    /**
+     * Generates the id attribute for the subelement of the modgrade group.
+     *
+     * Uses algorithm similar to what {@link HTML_QuickForm_element::_generateId()}
+     * does but takes the name of the wrapping modgrade group into account.
+     *
+     * @param string $subname the name of the HTML_QuickForm_element in this modgrade group
+     * @return string
+     */
+    protected function generate_modgrade_subelement_id($subname) {
+        $gid = str_replace(array('[', ']'), array('_', ''), $this->getName());
+        return clean_param('id_'.$gid.'_'.$subname, PARAM_ALPHANUMEXT);
+    }
+}

lib/form/modvisible.php

@@ -0,0 +1,156 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Drop down form element to select visibility in an activity mod update form
+ *
+ * Contains HTML class for a drop down element to select visibility in an activity mod update form
+ *
+ * @package   core_form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+require_once "$CFG->libdir/form/select.php";
+
+/**
+ * Drop down form element to select visibility in an activity mod update form
+ *
+ * HTML class for a drop down element to select visibility in an activity mod update form
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_modvisible extends MoodleQuickForm_select{
+
+    /** @var int activity state: visible=0, visibleoncoursepage=any */
+    const HIDE = 0;
+
+    /** @var int activity state: visible=1, visibleoncoursepage=1 */
+    const SHOW = 1;
+
+    /** @var int activity state: visible=1, visibleoncoursepage=0 */
+    const STEALTH = -1;
+
+    /**
+     * Class constructor
+     *
+     * @param string $elementName Select name attribute
+     * @param mixed $elementLabel Label(s) for the select
+     * @param mixed $attributes Either a typical HTML attribute string or an associative array
+     * @param array $options ignored
+     */
+    public function __construct($elementName=null, $elementLabel=null, $attributes=null, $options=null) {
+        parent::__construct($elementName, $elementLabel, null, $attributes);
+        $this->_type = 'modvisible';
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_modvisible($elementName=null, $elementLabel=null, $attributes=null, $options=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $attributes, $options);
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return bool
+     */
+    public function onQuickFormEvent($event, $arg, &$caller) {
+        switch ($event) {
+            case 'createElement':
+                $options = is_array($arg[3]) ? $arg[3] : [];
+                $sectionvisible = array_key_exists('sectionvisible', $options) ? $options['sectionvisible'] : 1;
+                $cm = !empty($options['cm']) ? cm_info::create($options['cm']) : null;
+                $choices = array();
+                if (!$sectionvisible) {
+                    // If section is not visible the activity is hidden by default but it can also be made available.
+                    $choices[self::HIDE] = get_string('hidefromstudents');
+                    if (!$cm || $cm->has_view()) {
+                        $choices[self::SHOW] = get_string('hideoncoursepage');
+                    }
+                } else {
+                    $choices[self::SHOW] = get_string('showoncoursepage');
+                    $choices[self::HIDE] = get_string('hidefromstudents');
+                    if (!empty($options['allowstealth']) && (!$cm || $cm->has_view())) {
+                        // If allowed in this course/section, add a third visibility option
+                        // "Available but not displayed on course page".
+                        $choices[self::STEALTH] = get_string('hideoncoursepage');
+                    }
+                }
+                $this->load($choices);
+                break;
+            case 'updateValue':
+                // Given two bool values of 'visible' and 'visibleoncoursepage' convert to a single
+                // three-state value (show, hide, hide-on-course-page).
+                $name = $this->getName();
+                $value = $this->_findValue($caller->_constantValues);
+                if (!empty($value) && isset($caller->_constantValues[$name.'oncoursepage']) &&
+                        !$caller->_constantValues[$name.'oncoursepage']) {
+                    $value = self::STEALTH;
+                }
+                if (null === $value) {
+                    if ($caller->isSubmitted()) {
+                        break;
+                    }
+                    $value = $this->_findValue($caller->_defaultValues);
+                    if (!empty($value) && isset($caller->_defaultValues[$name.'oncoursepage']) &&
+                            !$caller->_defaultValues[$name.'oncoursepage']) {
+                        $value = self::STEALTH;
+                    }
+                }
+                if ($value !== null) {
+                    $this->setSelected($value);
+                }
+                return true;
+
+        }
+        return parent::onQuickFormEvent($event, $arg, $caller);
+    }
+
+    /**
+     * As usual, to get the group's value we access its elements and call
+     * their exportValue() methods
+     *
+     * @param array $submitvalues submitted values
+     * @param bool $assoc if true the retured value is associated array
+     * @return mixed
+     */
+    public function exportValue(&$submitvalues, $assoc = false) {
+        if ($assoc) {
+            $value = parent::exportValue($submitvalues, $assoc);
+            $key = key($value);
+            $v = $value[$key];
+            // Convert three-state dropdown value (show, hide, hide-on-course-page) into the array of two bool values:
+            // array('visible' => x, 'visibleoncoursepage' => y).
+            return array($key => ($v == self::HIDE ? 0 : 1),
+                $key . 'oncoursepage' => ($v == self::STEALTH ? 0 : 1));
+        } else {
+            return parent::exportValue($submitvalues, $assoc);
+        }
+    }
+}

lib/form/password.php

@@ -0,0 +1,106 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Password type form element
+ *
+ * Contains HTML class for a password type element
+ *
+ * @package   core_form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once('HTML/QuickForm/password.php');
+require_once('templatable_form_element.php');
+
+/**
+ * Password type form element
+ *
+ * HTML class for a password type element
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_password extends HTML_QuickForm_password implements templatable {
+    use templatable_form_element;
+
+    /** @var string, html for help button, if empty then no help */
+    var $_helpbutton='';
+
+    /** @var bool if true label will be hidden. */
+    protected $_hiddenLabel = false;
+
+    /**
+     * constructor
+     *
+     * @param string $elementName (optional) name of the password element
+     * @param string $elementLabel (optional) label for password element
+     * @param mixed $attributes (optional) Either a typical HTML attribute string
+     *              or an associative array
+     */
+    public function __construct($elementName=null, $elementLabel=null, $attributes=null) {
+        global $CFG;
+
+        // No standard mform in moodle should allow autocomplete of passwords.
+        if (empty($attributes)) {
+            $attributes = ['autocomplete' => 'new-password'];
+        } else if (is_array($attributes) && empty($attributes['autocomplete'])) {
+            $attributes['autocomplete'] = 'new-password';
+        } else if (is_array($attributes) && $attributes['autocomplete'] === 'off') {
+            // A value of 'off' is ignored in all modern browsers and password
+            // managers and should be new-password instead.
+            $attributes['autocomplete'] = 'new-password';
+        } else if (is_string($attributes)) {
+            if (strpos($attributes, 'autocomplete') === false) {
+                $attributes .= ' autocomplete="new-password" ';
+            }
+        }
+
+        parent::__construct($elementName, $elementLabel, $attributes);
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_password($elementName=null, $elementLabel=null, $attributes=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $attributes);
+    }
+
+    /**
+     * get html for help button
+     *
+     * @return string html for help button
+     */
+    function getHelpButton(){
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Sets label to be hidden
+     *
+     * @param bool $hiddenLabel sets if label should be hidden
+     */
+    public function setHiddenLabel($hiddenLabel) {
+        $this->_hiddenLabel = $hiddenLabel;
+    }
+}

lib/form/passwordunmask.php

@@ -0,0 +1,100 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Password type form element with unmask option
+ *
+ * Contains HTML class for a password type element with unmask option
+ *
+ * @package   core_form
+ * @copyright 2009 Petr Skoda
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+if (!defined('MOODLE_INTERNAL')) {
+    die('Direct access to this script is forbidden.');    ///  It must be included from a Moodle page
+}
+
+global $CFG;
+require_once($CFG->libdir.'/form/password.php');
+
+/**
+ * Password type form element with unmask option
+ *
+ * HTML class for a password type element with unmask option
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2009 Petr Skoda {@link http://skodak.org}
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_passwordunmask extends MoodleQuickForm_password {
+    /**
+     * constructor
+     *
+     * @param string $elementName (optional) name of the password element
+     * @param string $elementLabel (optional) label for password element
+     * @param mixed $attributes (optional) Either a typical HTML attribute string
+     *              or an associative array
+     */
+    public function __construct($elementName=null, $elementLabel=null, $attributes=null) {
+        $this->_persistantFreeze = true;
+
+        parent::__construct($elementName, $elementLabel, $attributes);
+        $this->setType('passwordunmask');
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_passwordunmask($elementName=null, $elementLabel=null, $attributes=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $attributes);
+    }
+
+    /**
+     * Function to export the renderer data in a format that is suitable for a mustache template.
+     *
+     * @param renderer_base $output Used to do a final render of any components that need to be rendered for export.
+     * @return stdClass|array
+     */
+    public function export_for_template(renderer_base $output) {
+        $context = parent::export_for_template($output);
+        $context['valuechars'] = array_fill(0, strlen($context['value'] ?? ''), 'x');
+
+        return $context;
+    }
+
+    /**
+     * Check that there is no whitespace at the beginning and end of the password.
+     *
+     * It turned out that wrapping whitespace can easily be pasted by accident when copying the text from elsewhere.
+     * Such a mistake is very hard to debug as the whitespace is not displayed.
+     *
+     * @param string $value Submitted value.
+     * @return string|null Validation error message or null.
+     */
+    public function validateSubmitValue($value) {
+        if ($value !== null && $value !== trim($value)) {
+            return get_string('err_wrappingwhitespace', 'core_form');
+        }
+
+        return;
+    }
+}

lib/form/questioncategory.php

@@ -0,0 +1,77 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Drop down for question categories.
+ *
+ * Contains HTML class for a drop down element to select a question category.
+ *
+ * @package   core_form
+ * @copyright 2007 Tim Hunt
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+use qbank_managecategories\helper;
+require_once("$CFG->libdir/form/selectgroups.php");
+require_once("$CFG->libdir/questionlib.php");
+
+/**
+ * Drop down for question categories.
+ *
+ * HTML class for a drop down element to select a question category.
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2007 Tim Hunt
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_questioncategory extends MoodleQuickForm_selectgroups {
+    /** @var array default options for question categories */
+    var $_options = array('top'=>false, 'currentcat'=>0, 'nochildrenof' => -1);
+
+    /**
+     * Constructor
+     *
+     * @param string $elementName Select name attribute
+     * @param mixed $elementLabel Label(s) for the select
+     * @param array $options additional options. Recognised options are courseid, published and
+     *              only_editable, corresponding to the arguments of question_category_options
+     *              from moodlelib.php.
+     * @param mixed $attributes Either a typical HTML attribute string or an associative array
+     */
+    public function __construct($elementName = null, $elementLabel = null, $options = null, $attributes = null) {
+        parent::__construct($elementName, $elementLabel, array(), $attributes);
+        $this->_type = 'questioncategory';
+        if (is_array($options)) {
+            $this->_options = $options + $this->_options;
+            $this->loadArrayOptGroups(
+                        helper::question_category_options($this->_options['contexts'], $this->_options['top'],
+                            $this->_options['currentcat'], false, $this->_options['nochildrenof'], false));
+        }
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_questioncategory($elementName = null, $elementLabel = null, $options = null, $attributes = null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $options, $attributes);
+    }
+}

lib/form/radio.php

@@ -0,0 +1,130 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * radio type form element
+ *
+ * Contains HTML class for a radio type element
+ *
+ * @package   core_form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once('HTML/QuickForm/radio.php');
+require_once('templatable_form_element.php');
+/**
+ * radio type form element
+ *
+ * HTML class for a radio type element
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_radio extends HTML_QuickForm_radio implements templatable {
+    use templatable_form_element;
+
+    /** @var string html for help button, if empty then no help */
+    var $_helpbutton='';
+
+    /** @var bool if true label will be hidden. */
+    protected $_hiddenLabel = false;
+
+    /**
+     * constructor
+     *
+     * @param string $elementName (optional) name of the radio element
+     * @param string $elementLabel (optional) label for radio element
+     * @param string $text (optional) Text to put after the radio element
+     * @param string $value (optional) default value
+     * @param mixed $attributes (optional) Either a typical HTML attribute string
+     *              or an associative array
+     */
+    public function __construct($elementName=null, $elementLabel=null, $text=null, $value=null, $attributes=null) {
+        parent::__construct($elementName, $elementLabel, $text, $value, $attributes);
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_radio($elementName=null, $elementLabel=null, $text=null, $value=null, $attributes=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $text, $value, $attributes);
+    }
+
+    /**
+     * get html for help button
+     *
+     * @return string html for help button
+     */
+    function getHelpButton(){
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Slightly different container template when frozen.
+     *
+     * @return string
+     */
+    function getElementTemplateType(){
+        if ($this->_flagFrozen){
+            return 'static';
+        } else {
+            return 'default';
+        }
+    }
+
+    /**
+     * Returns the disabled field. Accessibility: the return "( )" from parent
+     * class is not acceptable for screenreader users, and we DO want a label.
+     *
+     * @return string
+     */
+    function getFrozenHtml()
+    {
+        $output = '<input type="radio" disabled="disabled" id="'.$this->getAttribute('id').'" ';
+        if ($this->getChecked()) {
+            $output .= 'checked="checked" />'.$this->_getPersistantData();
+        } else {
+            $output .= '/>';
+        }
+        return $output;
+    }
+
+    /**
+     * Returns HTML for advchecbox form element.
+     *
+     * @return string
+     */
+    function toHtml()
+    {
+        return '<span>' . parent::toHtml() . '</span>';
+    }
+
+    /**
+     * Sets label to be hidden
+     *
+     * @param bool $hiddenLabel sets if label should be hidden
+     */
+    public function setHiddenLabel($hiddenLabel) {
+        $this->_hiddenLabel = $hiddenLabel;
+    }
+}

lib/form/recaptcha.php

@@ -0,0 +1,129 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * recaptcha type form element
+ *
+ * Contains HTML class for a recaptcha type element
+ *
+ * @package   core_form
+ * @copyright 2008 Nicolas Connault <nicolasconnault@gmail.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once('HTML/QuickForm/input.php');
+require_once('templatable_form_element.php');
+
+/**
+ * recaptcha type form element
+ *
+ * HTML class for a recaptcha type element
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2008 Nicolas Connault <nicolasconnault@gmail.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_recaptcha extends HTML_QuickForm_input implements templatable {
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+
+    /** @var string html for help button, if empty then no help */
+    var $_helpbutton='';
+
+    /**
+     * constructor
+     *
+     * @param string $elementName (optional) name of the recaptcha element
+     * @param string $elementLabel (optional) label for recaptcha element
+     * @param mixed $attributes (optional) Either a typical HTML attribute string
+     *              or an associative array
+     */
+    public function __construct($elementName = null, $elementLabel = null, $attributes = null) {
+        parent::__construct($elementName, $elementLabel, $attributes);
+        $this->_type = 'recaptcha';
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_recaptcha($elementName = null, $elementLabel = null, $attributes = null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $attributes);
+    }
+
+    /**
+     * Returns the reCAPTCHA element in HTML
+     *
+     * @return string The HTML to render
+     */
+    public function toHtml() {
+        global $CFG;
+        require_once($CFG->libdir . '/recaptchalib_v2.php');
+
+        return recaptcha_get_challenge_html(RECAPTCHA_API_URL, $CFG->recaptchapublickey);
+    }
+
+    /**
+     * get html for help button
+     *
+     * @return string html for help button
+     */
+    function getHelpButton(){
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Checks recaptcha response with Google.
+     *
+     * @param string $responsestr
+     * @return bool
+     */
+    public function verify($responsestr) {
+        global $CFG;
+        require_once($CFG->libdir . '/recaptchalib_v2.php');
+
+        $response = recaptcha_check_response(RECAPTCHA_VERIFY_URL, $CFG->recaptchaprivatekey,
+                                           getremoteaddr(), $responsestr);
+        if (!$response['isvalid']) {
+            $attributes = $this->getAttributes();
+            $attributes['error_message'] = $response['error'];
+            $this->setAttributes($attributes);
+            return $response['error'];
+        }
+        return true;
+    }
+
+    public function export_for_template(renderer_base $output) {
+        $context = $this->export_for_template_base($output);
+        $context['html'] = $this->toHtml();
+        return $context;
+    }
+
+    /**
+     * Get force LTR option.
+     *
+     * @return bool
+     */
+    public function get_force_ltr() {
+        return true;
+    }
+
+}

lib/form/searchableselector.php

@@ -0,0 +1,65 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Searchable selector field (alias for autocomplete).
+ *
+ * Allows auto-complete selector.
+ *
+ * @package   core_form
+ * @copyright 2015 Damyon Wiese <damyon@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+require_once($CFG->libdir . '/form/autocomplete.php');
+
+/**
+ * Form field type for selecting from a list of options.
+ *
+ * Allows auto-complete ajax searching.
+ *
+ * @package   core_form
+ * @copyright 2015 Damyon Wiese <damyon@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_searchableselector extends MoodleQuickForm_autocomplete {
+
+    /**
+     * Constructor
+     *
+     * @param string $elementname Element name
+     * @param mixed $elementlabel Label(s) for an element
+     * @param array $options List of valid options for the select
+     * @param array $attributes List of HTML attributes for the select
+     */
+    public function __construct($elementname = null, $elementlabel = null, $options = [], $attributes = []) {
+        unset($options['']);
+        $options = ['' => get_string('noselection', 'form')] + $options;
+        parent::__construct($elementname, $elementlabel, $options, $attributes);
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_searchableselector($elementName=null, $elementLabel=null, $options=null, $attributes=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $options, $attributes);
+    }
+}

lib/form/select.php

@@ -0,0 +1,238 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * select type form element
+ *
+ * Contains HTML class for a select type element
+ *
+ * @package   core_form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once('HTML/QuickForm/select.php');
+require_once('templatable_form_element.php');
+
+/**
+ * select type form element
+ *
+ * HTML class for a select type element
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_select extends HTML_QuickForm_select implements templatable {
+
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+
+    /** @var string html for help button, if empty then no help */
+    var $_helpbutton='';
+
+    /** @var bool if true label will be hidden */
+    var $_hiddenLabel=false;
+
+    /**
+     * constructor
+     *
+     * @param string $elementName Select name attribute
+     * @param mixed $elementLabel Label(s) for the select
+     * @param mixed $options Data to be used to populate options
+     * @param mixed $attributes Either a typical HTML attribute string or an associative array
+     */
+    public function __construct($elementName=null, $elementLabel=null, $options=null, $attributes=null) {
+        parent::__construct($elementName, $elementLabel, $options, $attributes);
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_select($elementName=null, $elementLabel=null, $options=null, $attributes=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $options, $attributes);
+    }
+
+    /**
+     * Sets label to be hidden
+     *
+     * @param bool $hiddenLabel sets if label should be hidden
+     */
+    function setHiddenLabel($hiddenLabel){
+        $this->_hiddenLabel = $hiddenLabel;
+    }
+
+    /**
+     * Returns HTML for select form element.
+     *
+     * @return string
+     */
+    function toHtml(){
+        $html = '';
+        if ($this->getMultiple()) {
+            // Adding an hidden field forces the browser to send an empty data even though the user did not
+            // select any element. This value will be cleaned up in self::exportValue() as it will not be part
+            // of the select options.
+            $html .= '<input type="hidden" name="'.$this->getName().'" value="_qf__force_multiselect_submission">';
+        }
+        if ($this->_hiddenLabel){
+            $this->_generateId();
+            $html .= '<label class="accesshide" for="'.$this->getAttribute('id').'" >'.$this->getLabel().'</label>';
+        }
+        $html .= parent::toHtml();
+        return $html;
+    }
+
+    /**
+     * get html for help button
+     *
+     * @return string html for help button
+     */
+    function getHelpButton(){
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Removes an OPTION from the SELECT
+     *
+     * @param string $value Value for the OPTION to remove
+     * @return void
+     */
+    function removeOption($value)
+    {
+        $key=array_search($value, $this->_values);
+        if ($key!==FALSE and $key!==null) {
+            unset($this->_values[$key]);
+        }
+        foreach ($this->_options as $key=>$option){
+            if ($option['attr']['value']==$value){
+                unset($this->_options[$key]);
+                // we must reindex the options because the ugly code in quickforms' select.php expects that keys are 0,1,2,3... !?!?
+                $this->_options = array_merge($this->_options);
+                return;
+            }
+        }
+    }
+
+    /**
+     * Removes all OPTIONs from the SELECT
+     */
+    function removeOptions()
+    {
+        $this->_options = array();
+    }
+
+    /**
+     * Slightly different container template when frozen. Don't want to use a label tag
+     * with a for attribute in that case for the element label but instead use a div.
+     * Templates are defined in renderer constructor.
+     *
+     * @return string
+     */
+    function getElementTemplateType(){
+        if ($this->_flagFrozen){
+            return 'static';
+        } else {
+            return 'default';
+        }
+    }
+
+   /**
+    * We check the options and return only the values that _could_ have been
+    * selected. We also return a scalar value if select is not "multiple"
+    *
+    * @param array $submitValues submitted values
+    * @param bool $assoc if true the retured value is associated array
+    * @return mixed
+    */
+    function exportValue(&$submitValues, $assoc = false)
+    {
+        $emptyvalue = $this->getMultiple() ? [] : null;
+        if (empty($this->_options)) {
+            return $this->_prepareValue($emptyvalue, $assoc);
+        }
+
+        $value = $this->_findValue($submitValues);
+        if (is_null($value)) {
+            $value = $this->getValue();
+        }
+        $value = (array)$value;
+
+        $cleaned = array();
+        foreach ($value as $v) {
+            foreach ($this->_options as $option) {
+                if ((string)$option['attr']['value'] === (string)$v) {
+                    $cleaned[] = (string)$option['attr']['value'];
+                    break;
+                }
+            }
+        }
+
+        if (empty($cleaned)) {
+            return $this->_prepareValue($emptyvalue, $assoc);
+        }
+        if ($this->getMultiple()) {
+            return $this->_prepareValue($cleaned, $assoc);
+        } else {
+            return $this->_prepareValue($cleaned[0], $assoc);
+        }
+    }
+
+    public function export_for_template(renderer_base $output) {
+        // For multi-selects, if there is not already a size set, then set a sensible default.
+        if ($this->getMultiple()) {
+            if (!isset($this->_attributes['size'])) {
+                $this->_attributes['size'] = min(count($this->_options), 10);
+            }
+        }
+
+        $context = $this->export_for_template_base($output);
+
+        $options = [];
+        // Standard option attributes.
+        $standardoptionattributes = ['text', 'value', 'selected', 'disabled'];
+        foreach ($this->_options as $option) {
+            if (is_array($this->_values) && in_array( (string) $option['attr']['value'], $this->_values)) {
+                $this->_updateAttrArray($option['attr'], ['selected' => 'selected']);
+            }
+            $o = [
+                'text' => $option['text'],
+                'value' => $option['attr']['value'],
+                'selected' => !empty($option['attr']['selected']),
+                'disabled' => !empty($option['attr']['disabled']),
+            ];
+            // Set other attributes.
+            $otheroptionattributes = [];
+            foreach ($option['attr'] as $attr => $value) {
+                if (!in_array($attr, $standardoptionattributes) && $attr != 'class' && !is_object($value)) {
+                    $otheroptionattributes[] = $attr . '="' . s($value) . '"';
+                }
+            }
+            $o['optionattributes'] = implode(' ', $otheroptionattributes);
+            $options[] = $o;
+        }
+        $context['options'] = $options;
+        $context['nameraw'] = $this->getName();
+
+        return $context;
+    }
+}

lib/form/selectgroups.php

@@ -0,0 +1,570 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * select type form element
+ *
+ * Class to dynamically create an HTML SELECT with all options grouped in optgroups
+ *
+ * @package   core_form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once('HTML/QuickForm/element.php');
+require_once('templatable_form_element.php');
+
+/**
+ * select type form element
+ *
+ * Class to dynamically create an HTML SELECT with all options grouped in optgroups
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2007 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_selectgroups extends HTML_QuickForm_element implements templatable {
+
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+
+    /** @var bool add choose option */
+    var $showchoose = false;
+
+    /** @var array Contains the select optgroups */
+    var $_optGroups = array();
+
+    /** @var array Default values of the SELECT */
+    var $_values = null;
+
+    /** @var string html for help button, if empty then no help */
+    var $_helpbutton='';
+
+    /** @var bool if true label will be hidden */
+    var $_hiddenLabel=false;
+
+    /**
+     * Class constructor
+     *
+     * @param string $elementName Select name attribute
+     * @param mixed $elementLabel Label(s) for the select
+     * @param array $optgrps Data to be used to populate options
+     * @param mixed $attributes Either a typical HTML attribute string or an associative array
+     * @param bool $showchoose add standard moodle "Choose..." option as first item
+     */
+    public function __construct($elementName=null, $elementLabel=null, $optgrps=null, $attributes=null, $showchoose=false)
+    {
+        $this->showchoose = $showchoose;
+        parent::__construct($elementName, $elementLabel, $attributes);
+        $this->_persistantFreeze = true;
+        $this->_type = 'selectgroups';
+        if (isset($optgrps)) {
+            $this->loadArrayOptGroups($optgrps);
+        }
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_selectgroups($elementName=null, $elementLabel=null, $optgrps=null, $attributes=null, $showchoose=false) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $optgrps, $attributes, $showchoose);
+    }
+
+    /**
+     * Sets the default values of the select box
+     *
+     * @param mixed $values Array or comma delimited string of selected values
+     */
+    function setSelected($values)
+    {
+        if (is_string($values) && $this->getMultiple()) {
+            $values = preg_split("/[ ]?,[ ]?/", $values);
+        }
+        if (is_array($values)) {
+            $this->_values = array_values($values);
+        } else {
+            $this->_values = array($values);
+        }
+    }
+
+    /**
+     * Returns an array of the selected values
+     *
+     * @return array of selected values
+     */
+    function getSelected()
+    {
+        return $this->_values;
+    }
+
+    /**
+     * Sets the input field name
+     *
+     * @param string $name Input field name attribute
+     */
+    function setName($name)
+    {
+        $this->updateAttributes(array('name' => $name));
+    }
+
+    /**
+     * Returns the element name
+     *
+     * @return string
+     */
+    function getName()
+    {
+        return $this->getAttribute('name');
+    }
+
+    /**
+     * Returns the element name (possibly with brackets appended)
+     *
+     * @return string
+     */
+    function getPrivateName()
+    {
+        if ($this->getAttribute('multiple')) {
+            return $this->getName() . '[]';
+        } else {
+            return $this->getName();
+        }
+    }
+
+    /**
+     * Sets the value of the form element
+     *
+     * @param mixed $value Array or comma delimited string of selected values
+     */
+    function setValue($value)
+    {
+        $this->setSelected($value);
+    }
+
+    /**
+     * Returns an array of the selected values
+     *
+     * @return array of selected values
+     */
+    function getValue()
+    {
+        return $this->_values;
+    }
+
+    /**
+     * Sets the select field size, only applies to 'multiple' selects
+     *
+     * @param int $size Size of select  field
+     */
+    function setSize($size)
+    {
+        $this->updateAttributes(array('size' => $size));
+    }
+
+    /**
+     * Returns the select field size
+     *
+     * @return int
+     */
+    function getSize()
+    {
+        return $this->getAttribute('size');
+    }
+
+    /**
+     * Sets the select mutiple attribute
+     *
+     * @param bool $multiple Whether the select supports multi-selections
+     */
+    function setMultiple($multiple)
+    {
+        if ($multiple) {
+            $this->updateAttributes(array('multiple' => 'multiple'));
+        } else {
+            $this->removeAttribute('multiple');
+        }
+    }
+
+    /**
+     * Returns the select mutiple attribute
+     *
+     * @return bool true if multiple select, false otherwise
+     */
+    function getMultiple()
+    {
+        return (bool)$this->getAttribute('multiple');
+    }
+
+    /**
+     * Loads the options from an associative array
+     *
+     * @param array $arr Associative array of options
+     * @param mixed $values (optional) Array or comma delimited string of selected values
+     * @return PEAR_Error|bool on error or true
+     * @throws PEAR_Error
+     */
+    function loadArrayOptGroups($arr, $values=null)
+    {
+        if (!is_array($arr)) {
+            return self::raiseError('Argument 1 of HTML_Select::loadArrayOptGroups is not a valid array');
+        }
+        if (isset($values)) {
+            $this->setSelected($values);
+        }
+        foreach ($arr as $key => $val) {
+            // Warning: new API since release 2.3
+            $this->addOptGroup($key, $val);
+        }
+        return true;
+    }
+
+    /**
+     * Adds a new OPTION to the SELECT
+     *
+     * @param string $text Display text for the OPTION
+     * @param string $value Value for the OPTION
+     * @param mixed $attributes Either a typical HTML attribute string
+     *              or an associative array
+     */
+    function addOptGroup($text, $value, $attributes=null)
+    {
+        if (null === $attributes) {
+            $attributes = array('label' => $text);
+        } else {
+            $attributes = $this->_parseAttributes($attributes);
+            $this->_updateAttrArray($attributes, array('label' => $text));
+        }
+        $index = count($this->_optGroups);
+        $this->_optGroups[$index] = array('attr' => $attributes);
+        $this->loadArrayOptions($index, $value);
+    }
+
+    /**
+     * Loads the options from an associative array
+     *
+     * @param string $optgroup name of the options group
+     * @param array $arr Associative array of options
+     * @param mixed $values (optional) Array or comma delimited string of selected values
+     * @return PEAR_Error|bool on error or true
+     * @throws PEAR_Error
+     */
+    function loadArrayOptions($optgroup, $arr, $values=null)
+    {
+        if (!is_array($arr)) {
+            return self::raiseError('Argument 1 of HTML_Select::loadArray is not a valid array');
+        }
+        if (isset($values)) {
+            $this->setSelected($values);
+        }
+        foreach ($arr as $key => $val) {
+            // Warning: new API since release 2.3
+            $this->addOption($optgroup, $val, $key);
+        }
+        return true;
+    }
+
+    /**
+     * Adds a new OPTION to an optgroup
+     *
+     * @param string $optgroup name of the option group
+     * @param string $text Display text for the OPTION
+     * @param string $value Value for the OPTION
+     * @param mixed $attributes Either a typical HTML attribute string
+     *              or an associative array
+     */
+    function addOption($optgroup, $text, $value, $attributes=null)
+    {
+        if (null === $attributes) {
+            $attributes = array('value' => $value);
+        } else {
+            $attributes = $this->_parseAttributes($attributes);
+            if (isset($attributes['selected'])) {
+                // the 'selected' attribute will be set in toHtml()
+                $this->_removeAttr('selected', $attributes);
+                if (is_null($this->_values)) {
+                    $this->_values = array($value);
+                } elseif (!in_array($value, $this->_values)) {
+                    $this->_values[] = $value;
+                }
+            }
+            $this->_updateAttrArray($attributes, array('value' => $value));
+        }
+        $this->_optGroups[$optgroup]['options'][] = array('text' => $text, 'attr' => $attributes);
+    }
+
+    /**
+     * Returns the SELECT in HTML
+     *
+     * @return string
+     */
+    function toHtml()
+    {
+        if ($this->_flagFrozen) {
+            return $this->getFrozenHtml();
+        } else {
+            $tabs    = $this->_getTabs();
+            $strHtml = '';
+
+            if ($this->getComment() != '') {
+                $strHtml .= $tabs . '<!-- ' . $this->getComment() . " //-->\n";
+            }
+
+            if (!$this->getMultiple()) {
+                $attrString = $this->_getAttrString($this->_attributes);
+            } else {
+                $myName = $this->getName();
+                $this->setName($myName . '[]');
+                $attrString = $this->_getAttrString($this->_attributes);
+                $this->setName($myName);
+            }
+            $strHtml .= $tabs;
+            if ($this->_hiddenLabel){
+                $this->_generateId();
+                $strHtml .= '<label class="accesshide" for="'.$this->getAttribute('id').'" >'.
+                            $this->getLabel().'</label>';
+            }
+            $strHtml .=  '<select' . $attrString . ">\n";
+            if ($this->showchoose) {
+                $strHtml .= $tabs . "\t\t<option value=\"\">" . get_string('choose') . "...</option>\n";
+            }
+            foreach ($this->_optGroups as $optGroup) {
+                if (empty($optGroup['options'])) {
+                    //xhtml strict
+                    continue;
+                }
+                $strHtml .= $tabs . "\t<optgroup" . ($this->_getAttrString($optGroup['attr'])) . '>';
+                foreach ($optGroup['options'] as $option){
+                    if (is_array($this->_values) && in_array((string)$option['attr']['value'], $this->_values)) {
+                        $this->_updateAttrArray($option['attr'], array('selected' => 'selected'));
+                    }
+                    $strHtml .= $tabs . "\t\t<option" . $this->_getAttrString($option['attr']) . '>' .
+                                $option['text'] . "</option>\n";
+                }
+                $strHtml .= $tabs . "\t</optgroup>\n";
+            }
+            return $strHtml . $tabs . '</select>';
+        }
+    }
+
+    /**
+     * Returns the value of field without HTML tags
+     *
+     * @return string
+     */
+    function getFrozenHtml()
+    {
+        $value = array();
+        if (is_array($this->_values)) {
+            foreach ($this->_values as $key => $val) {
+                foreach ($this->_optGroups as $optGroup) {
+                    if (empty($optGroup['options'])) {
+                        continue;
+                    }
+                    for ($i = 0, $optCount = count($optGroup['options']); $i < $optCount; $i++) {
+                        if ((string)$val == (string)$optGroup['options'][$i]['attr']['value']) {
+                            $value[$key] = $optGroup['options'][$i]['text'];
+                            break;
+                        }
+                    }
+                }
+            }
+        }
+        $html = empty($value)? '&nbsp;': join('<br />', $value);
+        if ($this->_persistantFreeze) {
+            $name = $this->getPrivateName();
+            // Only use id attribute if doing single hidden input
+            if (1 == count($value)) {
+                $id     = $this->getAttribute('id');
+                $idAttr = isset($id)? array('id' => $id): array();
+            } else {
+                $idAttr = array();
+            }
+            foreach ($value as $key => $item) {
+                $html .= '<input' . $this->_getAttrString(array(
+                             'type'  => 'hidden',
+                             'name'  => $name,
+                             'value' => $this->_values[$key]
+                         ) + $idAttr) . ' />';
+            }
+        }
+        return $html;
+    }
+
+   /**
+    * We check the options and return only the values that _could_ have been
+    * selected. We also return a scalar value if select is not "multiple"
+    *
+    * @param array $submitValues submitted values
+    * @param bool $assoc if true the retured value is associated array
+    * @return mixed
+    */
+    function exportValue(&$submitValues, $assoc = false)
+    {
+        if (empty($this->_optGroups)) {
+            return $this->_prepareValue(null, $assoc);
+        }
+
+        $value = $this->_findValue($submitValues);
+        if (is_null($value)) {
+            $value = $this->getValue();
+        }
+        $value = (array)$value;
+
+        $cleaned = array();
+        foreach ($value as $v) {
+            foreach ($this->_optGroups as $optGroup){
+                if (empty($optGroup['options'])) {
+                    continue;
+                }
+                foreach ($optGroup['options'] as $option) {
+                    if ((string)$option['attr']['value'] === (string)$v) {
+                        $cleaned[] = (string)$option['attr']['value'];
+                        break;
+                    }
+                }
+            }
+        }
+
+        if (empty($cleaned)) {
+            return $this->_prepareValue(null, $assoc);
+        }
+        if ($this->getMultiple()) {
+            return $this->_prepareValue($cleaned, $assoc);
+        } else {
+            return $this->_prepareValue($cleaned[0], $assoc);
+        }
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return bool
+     */
+    function onQuickFormEvent($event, $arg, &$caller)
+    {
+        if ('updateValue' == $event) {
+            $value = $this->_findValue($caller->_constantValues);
+            if (null === $value) {
+                $value = $this->_findValue($caller->_submitValues);
+                // Fix for bug #4465 & #5269
+                // XXX: should we push this to element::onQuickFormEvent()?
+                if (null === $value && (!$caller->isSubmitted() || !$this->getMultiple())) {
+                    $value = $this->_findValue($caller->_defaultValues);
+                }
+            }
+            if (null !== $value) {
+                $this->setValue($value);
+            }
+            return true;
+        } else {
+            return parent::onQuickFormEvent($event, $arg, $caller);
+        }
+    }
+
+    /**
+     * Sets label to be hidden
+     *
+     * @param bool $hiddenLabel sets if label should be hidden
+     */
+    function setHiddenLabel($hiddenLabel){
+        $this->_hiddenLabel = $hiddenLabel;
+    }
+
+    /**
+     * get html for help button
+     *
+     * @return string html for help button
+     */
+    function getHelpButton(){
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Slightly different container template when frozen. Don't want to use a label tag
+     * with a for attribute in that case for the element label but instead use a div.
+     * Templates are defined in renderer constructor.
+     *
+     * @return string
+     */
+    function getElementTemplateType(){
+        if ($this->_flagFrozen){
+            return 'static';
+        } else {
+            return 'default';
+        }
+    }
+
+    public function export_for_template(renderer_base $output) {
+        $context = $this->export_for_template_base($output);
+        $optiongroups = [];
+        if ($this->showchoose) {
+            $optionsgroups[] = [
+                'text' => get_string('choosedots')
+            ];
+        }
+
+        // Standard option attributes.
+        $standardoptionattributes = ['text', 'value', 'selected', 'disabled'];
+        foreach ($this->_optGroups as $group) {
+            $options = [];
+
+            if (empty($group['options'])) {
+                continue;
+            }
+            foreach ($group['options'] as $option) {
+                $o = ['value' => (string)$option['attr']['value']];
+                if (is_array($this->_values) && in_array($o['value'], $this->_values)) {
+                    $o['selected'] = true;
+                } else {
+                    $o['selected'] = false;
+                }
+                $o['text'] = $option['text'];
+                $o['disabled'] = !empty($option['attr']['disabled']);
+                // Set other attributes.
+                $otheroptionattributes = [];
+                foreach ($option['attr'] as $attr => $value) {
+                    if (!in_array($attr, $standardoptionattributes) && $attr != 'class' && !is_object($value)) {
+                        $otheroptionattributes[] = $attr . '="' . s($value) . '"';
+                    }
+                }
+                $o['optionattributes'] = implode(' ', $otheroptionattributes);
+                $options[] = $o;
+            }
+
+            $og = [
+                'text' => $group['attr']['label'],
+                'options' => $options
+            ];
+
+            $optiongroups[] = $og;
+        }
+        $context['optiongroups'] = $optiongroups;
+        // If the select is a static element and does not allow the user to change the value (Ex: Auth method),
+        // we need to change the label to static.
+        $context['staticlabel'] = $this->_flagFrozen;
+
+        return $context;
+    }
+}

lib/form/selectwithlink.php

@@ -0,0 +1,275 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * select type form element
+ *
+ * Contains HTML class for a select type element with options containing link
+ *
+ * @package   core_form
+ * @copyright 2008 Nicolas Connault <nicolasconnault@gmail.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once('HTML/QuickForm/select.php');
+require_once('templatable_form_element.php');
+
+/**
+ * select type form element
+ *
+ * HTML class for a select type element with options containing link
+ *
+ * @deprecated since 3.2
+ * @package   core_form
+ * @category  form
+ * @copyright 2008 Nicolas Connault <nicolasconnault@gmail.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_selectwithlink extends HTML_QuickForm_select implements templatable {
+
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+    /** @var string html for help button, if empty then no help */
+    var $_helpbutton='';
+
+    /** @var bool if true label will be hidden */
+    var $_hiddenLabel=false;
+
+    /** @var string url to which select option will be posted */
+    var $_link=null;
+
+    /** @var string data which will be posted to link */
+    var $_linklabel=null;
+
+    /** @var string url return link */
+    var $_linkreturn=null;
+
+    /**
+     * constructor
+     *
+     * @param string $elementName Select name attribute
+     * @param mixed $elementLabel Label(s) for the select
+     * @param array $options Data to be used to populate options
+     * @param mixed $attributes Either a typical HTML attribute string or an associative array
+     * @param bool $linkdata data to be posted
+     */
+    public function __construct($elementName=null, $elementLabel=null, $options=null, $attributes=null, $linkdata=null) {
+        if (!empty($linkdata['link']) && !empty($linkdata['label'])) {
+            $this->_link = $linkdata['link'];
+            $this->_linklabel = $linkdata['label'];
+        }
+
+        if (!empty($linkdata['return'])) {
+            $this->_linkreturn = $linkdata['return'];
+        }
+
+        parent::__construct($elementName, $elementLabel, $options, $attributes);
+
+        $this->_type = 'selectwithlink';
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_selectwithlink($elementName=null, $elementLabel=null, $options=null, $attributes=null, $linkdata=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $options, $attributes, $linkdata);
+    }
+
+    /**
+     * Sets label to be hidden
+     *
+     * @param bool $hiddenLabel sets if label should be hidden
+     */
+    function setHiddenLabel($hiddenLabel){
+        $this->_hiddenLabel = $hiddenLabel;
+    }
+
+    /**
+     * Returns the SELECT in HTML
+     *
+     * @return string
+     */
+    function toHtml(){
+        $retval = '';
+        if ($this->_hiddenLabel){
+            $this->_generateId();
+            $retval = '<label class="accesshide" for="'.$this->getAttribute('id').'" >'.
+                        $this->getLabel().'</label>'.parent::toHtml();
+        } else {
+             $retval = parent::toHtml();
+        }
+
+        if (!empty($this->_link)) {
+            if (!empty($this->_linkreturn) && is_array($this->_linkreturn)) {
+                $appendchar = '?';
+                if (strstr($this->_link, '?')) {
+                    $appendchar = '&amp;';
+                }
+
+                foreach ($this->_linkreturn as $key => $val) {
+                    $this->_link .= $appendchar."$key=$val";
+                    $appendchar = '&amp;';
+                }
+            }
+
+            $retval .= '<a style="margin-left: 5px" href="'.$this->_link.'">'.$this->_linklabel.'</a>';
+        }
+
+        return $retval;
+    }
+
+    /**
+     * get html for help button
+     *
+     * @return string html for help button
+     */
+    function getHelpButton(){
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Removes an OPTION from the SELECT
+     *
+     * @param string $value Value for the OPTION to remove
+     */
+    function removeOption($value)
+    {
+        $key=array_search($value, $this->_values);
+        if ($key!==FALSE and $key!==null) {
+            unset($this->_values[$key]);
+        }
+        foreach ($this->_options as $key=>$option){
+            if ($option['attr']['value']==$value){
+                unset($this->_options[$key]);
+                return;
+            }
+        }
+    }
+
+    /**
+     * Removes all OPTIONs from the SELECT
+     */
+    function removeOptions()
+    {
+        $this->_options = array();
+    }
+
+    /**
+     * Slightly different container template when frozen. Don't want to use a label tag
+     * with a for attribute in that case for the element label but instead use a div.
+     * Templates are defined in renderer constructor.
+     *
+     * @return string
+     */
+    function getElementTemplateType(){
+        if ($this->_flagFrozen){
+            return 'static';
+        } else {
+            return 'default';
+        }
+    }
+
+   /**
+    * We check the options and return only the values that _could_ have been
+    * selected. We also return a scalar value if select is not "multiple"
+    *
+    * @param array $submitValues submitted values
+    * @param bool $assoc if true the retured value is associated array
+    * @return mixed
+    */
+    function exportValue(&$submitValues, $assoc = false)
+    {
+        if (empty($this->_options)) {
+            return $this->_prepareValue(null, $assoc);
+        }
+
+        $value = $this->_findValue($submitValues);
+        if (is_null($value)) {
+            $value = $this->getValue();
+        }
+        $value = (array)$value;
+
+        $cleaned = array();
+        foreach ($value as $v) {
+            foreach ($this->_options as $option) {
+                if ((string)$option['attr']['value'] === (string)$v) {
+                    $cleaned[] = (string)$option['attr']['value'];
+                    break;
+                }
+            }
+        }
+
+        if (empty($cleaned)) {
+            return $this->_prepareValue(null, $assoc);
+        }
+        if ($this->getMultiple()) {
+            return $this->_prepareValue($cleaned, $assoc);
+        } else {
+            return $this->_prepareValue($cleaned[0], $assoc);
+        }
+    }
+
+    public function export_for_template(renderer_base $output) {
+        $context = $this->export_for_template_base($output);
+
+        $options = [];
+        // Standard option attributes.
+        $standardoptionattributes = ['text', 'value', 'selected', 'disabled'];
+        foreach ($this->_options as $option) {
+            if (is_array($this->_values) && in_array( (string) $option['attr']['value'], $this->_values)) {
+                $this->_updateAttrArray($option['attr'], ['selected' => 'selected']);
+            }
+            $o = [
+                'text' => $option['text'],
+                'value' => $option['attr']['value'],
+                'selected' => !empty($option['attr']['selected']),
+                'disabled' => !empty($option['attr']['disabled']),
+            ];
+            // Set other attributes.
+            $otheroptionattributes = [];
+            foreach ($option['attr'] as $attr => $value) {
+                if (!in_array($attr, $standardoptionattributes) && $attr != 'class' && !is_object($value)) {
+                    $otheroptionattributes[] = $attr . '="' . s($value) . '"';
+                }
+            }
+            $o['optionattributes'] = implode(' ', $otheroptionattributes);
+            $options[] = $o;
+        }
+        $context['options'] = $options;
+        if (!empty($this->_link)) {
+            if (!empty($this->_linkreturn) && is_array($this->_linkreturn)) {
+                $appendchar = '?';
+                if (strstr($this->_link, '?')) {
+                    $appendchar = '&amp;';
+                }
+
+                foreach ($this->_linkreturn as $key => $val) {
+                    $this->_link .= $appendchar."$key=$val";
+                    $appendchar = '&amp;';
+                }
+            }
+        }
+        $context['link'] = $this->_link;
+        $context['linklabel'] = $this->_linklabel;
+
+        return $context;
+    }
+}

lib/form/selectyesno.php

@@ -0,0 +1,88 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Yes/No drop down type form element
+ *
+ * Contains HTML class for a simple yes/ no drop down element
+ *
+ * @package   core_form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+require_once "$CFG->libdir/form/select.php";
+
+/**
+ * Yes/No drop down type form element
+ *
+ * HTML class for a simple yes/ no drop down element
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_selectyesno extends MoodleQuickForm_select{
+    /**
+     * Class constructor
+     *
+     * @param string $elementName Select name attribute
+     * @param mixed $elementLabel Label(s) for the select
+     * @param mixed $attributes Either a typical HTML attribute string or an associative array
+     * @param mixed $options ignored, not used.
+     */
+    public function __construct($elementName=null, $elementLabel=null, $attributes=null, $options=null) {
+        // TODO MDL-52313 Replace with the call to parent::__construct().
+        HTML_QuickForm_element::__construct($elementName, $elementLabel, $attributes, null);
+        $this->_type = 'selectyesno';
+        $this->_persistantFreeze = true;
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_selectyesno($elementName=null, $elementLabel=null, $attributes=null, $options=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $attributes, $options);
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return mixed
+     */
+    function onQuickFormEvent($event, $arg, &$caller)
+    {
+        switch ($event) {
+            case 'createElement':
+                $choices=array();
+                $choices[0] = get_string('no');
+                $choices[1] = get_string('yes');
+                $this->load($choices);
+                break;
+        }
+        return parent::onQuickFormEvent($event, $arg, $caller);
+    }
+
+}

lib/form/static.php

@@ -0,0 +1,97 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Text type form element
+ *
+ * Contains HTML class for a text type element
+ *
+ * @package   core_form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once("HTML/QuickForm/static.php");
+require_once('templatable_form_element.php');
+
+/**
+ * Text type element
+ *
+ * HTML class for a text type element
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_static extends HTML_QuickForm_static implements templatable {
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+
+    /** @var string Form element type */
+    var $_elementTemplateType='static';
+
+    /** @var string html for help button, if empty then no help */
+    var $_helpbutton='';
+
+    /**
+     * constructor
+     *
+     * @param string $elementName (optional) name of the text field
+     * @param string $elementLabel (optional) text field label
+     * @param string $text (optional) Text to put in text field
+     */
+    public function __construct($elementName=null, $elementLabel=null, $text=null) {
+        parent::__construct($elementName, $elementLabel, $text);
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_static($elementName=null, $elementLabel=null, $text=null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $text);
+    }
+
+    /**
+     * get html for help button
+     *
+     * @return string html for help button
+     */
+    function getHelpButton(){
+        return $this->_helpbutton;
+    }
+
+    /**
+     * Gets the type of form element
+     *
+     * @return string
+     */
+    function getElementTemplateType(){
+        return $this->_elementTemplateType;
+    }
+
+    public function export_for_template(renderer_base $output) {
+        $context = $this->export_for_template_base($output);
+        $context['html'] = $this->toHtml();
+        $context['staticlabel'] = true;
+        return $context;
+    }
+}

lib/form/submit.php

@@ -0,0 +1,156 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * submit type form element
+ *
+ * Contains HTML class for a submit type element
+ *
+ * @package   core_form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once("HTML/QuickForm/submit.php");
+require_once('templatable_form_element.php');
+
+/**
+ * submit type form element
+ *
+ * HTML class for a submit type element
+ *
+ * @package   core_form
+ * @category  form
+ * @copyright 2006 Jamie Pratt <me@jamiep.org>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_submit extends HTML_QuickForm_submit implements templatable {
+    use templatable_form_element {
+        export_for_template as export_for_template_base;
+    }
+
+    /**
+     * @var bool $primary Is this button a primary button?
+     */
+    protected $primary;
+
+    /**
+     * Any class apart from 'btn' would be overridden with this content.
+     *
+     * By default, submit buttons will utilize the btn-primary OR btn-secondary classes. However there are cases where we
+     * require a submit button with different stylings (e.g. btn-link). In these cases, $customclassoverride will override
+     * the defaults mentioned previously and utilize the provided class(es).
+     *
+     * @var string $customclassoverride Custom class override for the input element
+     */
+    protected $customclassoverride;
+
+    /**
+     * constructor
+     *
+     * @param string $elementName (optional) name of the field
+     * @param string $value (optional) field label
+     * @param string $attributes (optional) Either a typical HTML attribute string or an associative array
+     * @param bool|null $primary Is this button a primary button?
+     * @param array $options Options to further customise the submit button. Currently accepted options are:
+     *                  customclassoverride String The CSS class to use for the button instead of the standard
+     *                                             btn-primary and btn-secondary classes.
+     */
+    public function __construct($elementName=null, $value=null, $attributes=null, $primary = null, $options = []) {
+        parent::__construct($elementName, $value, $attributes);
+
+        // Fallback to legacy behaviour if no value specified.
+        if (is_null($primary)) {
+            $this->primary = $this->getName() != 'cancel';
+        } else {
+            $this->primary = $primary;
+        }
+
+        $this->customclassoverride = $options['customclassoverride'] ?? false;
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_submit($elementName=null, $value=null, $attributes=null, $primary = null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $value, $attributes, $primary);
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     */
+    function onQuickFormEvent($event, $arg, &$caller)
+    {
+        switch ($event) {
+            case 'createElement':
+                parent::onQuickFormEvent($event, $arg, $caller);
+                if ($caller->isNoSubmitButton($arg[0])){
+                    //need this to bypass client validation
+                    //for buttons that submit but do not process the
+                    //whole form.
+                    $onClick = $this->getAttribute('onclick');
+                    $skip = 'skipClientValidation = true;';
+                    $onClick = ($onClick !== null)?$skip.' '.$onClick:$skip;
+                    $this->updateAttributes(array('data-skip-validation' => 1, 'data-no-submit' => 1, 'onclick' => $onClick));
+                }
+                return true;
+                break;
+        }
+        return parent::onQuickFormEvent($event, $arg, $caller);
+
+    }
+
+    /**
+     * Slightly different container template when frozen. Don't want to display a submit
+     * button if the form is frozen.
+     *
+     * @return string
+     */
+    function getElementTemplateType(){
+        if ($this->_flagFrozen){
+            return 'nodisplay';
+        } else {
+            return 'actionbuttons';
+        }
+    }
+
+    /**
+     * Freeze the element so that only its value is returned
+     */
+    function freeze(){
+        $this->_flagFrozen = true;
+    }
+
+    public function export_for_template(renderer_base $output) {
+        $context = $this->export_for_template_base($output);
+        if (!$this->primary) {
+            $context['secondary'] = true;
+        }
+
+        if ($this->customclassoverride) {
+            $context['customclassoverride'] = $this->customclassoverride;
+        }
+        return $context;
+    }
+}

lib/form/tags.php

@@ -0,0 +1,274 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+
+/**
+ * Tag autocomplete field.
+ *
+ * Contains HTML class for editing tags, both standard and not.
+ *
+ * @package   core_form
+ * @copyright 2009 Tim Hunt
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+global $CFG;
+require_once($CFG->libdir . '/form/autocomplete.php');
+
+/**
+ * Form field type for editing tags.
+ *
+ * HTML class for editing tags, both standard and not.
+ *
+ * @package   core_form
+ * @copyright 2009 Tim Hunt
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class MoodleQuickForm_tags extends MoodleQuickForm_autocomplete {
+    /**
+     * Inidcates that the user should be the usual interface, with the official
+     * tags listed seprately, and a text box where they can type anything.
+     * @deprecated since 3.1
+     * @var int
+     */
+    const DEFAULTUI = 'defaultui';
+
+    /**
+     * Indicates that the user should only be allowed to select official tags.
+     * @deprecated since 3.1
+     * @var int
+     */
+    const ONLYOFFICIAL = 'onlyofficial';
+
+    /**
+     * Indicates that the user should just be given a text box to type in (they
+     * can still type official tags though.
+     * @deprecated since 3.1
+     * @var int
+     */
+    const NOOFFICIAL = 'noofficial';
+
+    /**
+     * @var boolean $showstandard Standard tags suggested? (if not, then don't show link to manage standard tags).
+     */
+    protected $showstandard = false;
+
+    /**
+     * Options passed when creating an element.
+     * @var array
+     */
+    protected $tagsoptions = array();
+
+    /**
+     * Constructor
+     *
+     * @param string $elementName Element name
+     * @param mixed $elementLabel Label(s) for an element
+     * @param array $options Options to control the element's display
+     * @param mixed $attributes Either a typical HTML attribute string or an associative array.
+     */
+    public function __construct($elementName = null, $elementLabel = null, $options = array(), $attributes = null) {
+        $validoptions = array();
+
+        if (!empty($options)) {
+            // Only execute it when the element was created and $options has values set by user.
+            // In onQuickFormEvent() we make sure that $options is not empty even if developer left it empty.
+            $showstandard = core_tag_tag::BOTH_STANDARD_AND_NOT;
+            if (isset($options['showstandard'])) {
+                $showstandard = $options['showstandard'];
+            } else if (isset($options['display'])) {
+                debugging('Option "display" is deprecated, each tag area can be configured to show standard tags or not ' .
+                    'by admin or manager. If it is necessary for the developer to override it, please use "showstandard" option',
+                    DEBUG_DEVELOPER);
+                if ($options['display'] === self::NOOFFICIAL) {
+                    $showstandard = core_tag_tag::HIDE_STANDARD;
+                } else if ($options['display'] === self::ONLYOFFICIAL) {
+                    $showstandard = core_tag_tag::STANDARD_ONLY;
+                }
+            } else if (!empty($options['component']) && !empty($options['itemtype'])) {
+                $showstandard = core_tag_area::get_showstandard($options['component'], $options['itemtype']);
+            }
+
+            $this->tagsoptions = $options;
+
+            $this->showstandard = ($showstandard != core_tag_tag::HIDE_STANDARD);
+            if ($this->showstandard) {
+                $validoptions = $this->load_standard_tags();
+            }
+            // Option 'tags' allows us to type new tags.
+            $attributes['tags'] = ($showstandard != core_tag_tag::STANDARD_ONLY);
+            $attributes['multiple'] = 'multiple';
+            $attributes['placeholder'] = get_string('entertags', 'tag');
+            $attributes['showsuggestions'] = $this->showstandard;
+        }
+
+
+        parent::__construct($elementName, $elementLabel, $validoptions, $attributes);
+        $this->_type = 'tags';
+    }
+
+    /**
+     * Called by HTML_QuickForm whenever form event is made on this element
+     *
+     * @param string $event Name of event
+     * @param mixed $arg event arguments
+     * @param object $caller calling object
+     * @return bool
+     */
+    public function onQuickFormEvent($event, $arg, &$caller) {
+        if ($event === 'createElement') {
+            if (!is_array($arg[2])) {
+                $arg[2] = [];
+            }
+            $arg[2] += array('itemtype' => '', 'component' => '');
+        }
+        return parent::onQuickFormEvent($event, $arg, $caller);
+    }
+
+    /**
+     * Checks if tagging is enabled for this itemtype
+     *
+     * @return boolean
+     */
+    protected function is_tagging_enabled() {
+        if (!empty($this->tagsoptions['itemtype']) && !empty($this->tagsoptions['component'])) {
+            $enabled = core_tag_tag::is_enabled($this->tagsoptions['component'], $this->tagsoptions['itemtype']);
+            if ($enabled === false) {
+                return false;
+            }
+        }
+        // Backward compatibility with code developed before Moodle 3.0 where itemtype/component were not specified.
+        return true;
+    }
+
+    /**
+     * Old syntax of class constructor. Deprecated in PHP7.
+     *
+     * @deprecated since Moodle 3.1
+     */
+    public function MoodleQuickForm_tags($elementName = null, $elementLabel = null, $options = array(), $attributes = null) {
+        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
+        self::__construct($elementName, $elementLabel, $options, $attributes);
+    }
+
+    /**
+     * Finds the tag collection to use for standard tag selector
+     *
+     * @return int
+     */
+    protected function get_tag_collection() {
+        if (empty($this->tagsoptions['tagcollid']) && (empty($this->tagsoptions['itemtype']) ||
+                empty($this->tagsoptions['component']))) {
+            debugging('You need to specify \'itemtype\' and \'component\' of the tagged '
+                    . 'area in the tags form element options',
+                    DEBUG_DEVELOPER);
+        }
+        if (!empty($this->tagsoptions['tagcollid'])) {
+            return $this->tagsoptions['tagcollid'];
+        }
+        if ($this->tagsoptions['itemtype']) {
+            $this->tagsoptions['tagcollid'] = core_tag_area::get_collection($this->tagsoptions['component'],
+                    $this->tagsoptions['itemtype']);
+        } else {
+            $this->tagsoptions['tagcollid'] = core_tag_collection::get_default();
+        }
+        return $this->tagsoptions['tagcollid'];
+    }
+
+    /**
+     * Returns HTML for select form element.
+     *
+     * @return string
+     */
+    function toHtml(){
+        global $OUTPUT;
+
+        $managelink = '';
+        if (has_capability('moodle/tag:manage', context_system::instance()) && $this->showstandard) {
+            $url = new moodle_url('/tag/manage.php', array('tc' => $this->get_tag_collection()));
+            $managelink = ' ' . $OUTPUT->action_link($url, get_string('managestandardtags', 'tag'));
+        }
+
+        return parent::toHTML() . $managelink;
+    }
+
+    /**
+     * Accepts a renderer
+     *
+     * @param HTML_QuickForm_Renderer $renderer An HTML_QuickForm_Renderer object
+     * @param bool $required Whether a group is required
+     * @param string $error An error message associated with a group
+     */
+    public function accept(&$renderer, $required = false, $error = null) {
+        if ($this->is_tagging_enabled()) {
+            $renderer->renderElement($this, $required, $error);
+        } else {
+            $renderer->renderHidden($this);
+        }
+    }
+
+    /**
+     * Internal function to load standard tags
+     */
+    protected function load_standard_tags() {
+        global $CFG, $DB;
+        if (!$this->is_tagging_enabled()) {
+            return array();
+        }
+        $namefield = empty($CFG->keeptagnamecase) ? 'name' : 'rawname';
+        $tags = $DB->get_records_menu('tag',
+            array('isstandard' => 1, 'tagcollid' => $this->get_tag_collection()),
+            $namefield, 'id,' . $namefield);
+        return array_combine($tags, $tags);
+    }
+
+    /**
+     * Returns a 'safe' element's value
+     *
+     * @param  array  $submitValues array of submitted values to search
+     * @param  bool   $assoc        whether to return the value as associative array
+     * @return mixed
+     */
+    public function exportValue(&$submitValues, $assoc = false) {
+        if (!$this->is_tagging_enabled()) {
+            return $this->_prepareValue([], $assoc);
+        }
+        if ($this->_findValue($submitValues) === '_qf__force_multiselect_submission') {
+            // Nothing was selected.
+            return $this->_prepareValue([], $assoc);
+        }
+
+        // Submitted tag data will be encoded, we want original text.
+        if (array_key_exists($this->getName(), $submitValues)) {
+            array_walk($submitValues[$this->getName()], static function(string &$tag): void {
+                $tag = html_entity_decode($tag, ENT_COMPAT);
+            });
+        }
+
+        return parent::exportValue($submitValues, $assoc);
+    }
+
+    public function export_for_template(renderer_base $output) {
+
+        $context = parent::export_for_template($output);
+        if (has_capability('moodle/tag:manage', context_system::instance()) && $this->showstandard) {
+            $url = new moodle_url('/tag/manage.php', array('tc' => $this->get_tag_collection()));
+            $context['managestandardtagsurl'] = $url->out(false);
+        }
+
+        return $context;
+    }
+}

lib/form/templatable_form_element.php

@@ -0,0 +1,97 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Adds export_for_template behaviour to an mform element in a consistent and predictable way.
+ *
+ * @package   core_form
+ * @copyright 2016 Damyon Wiese
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+defined('MOODLE_INTERNAL') || die();
+
+// Some form elements are used before $CFG is created - do not rely on it here.
+require_once(__DIR__ . '/../outputcomponents.php');
+
+/**
+ * templatable_form_element trait.
+ *
+ * @package   core_form
+ * @copyright 2016 Damyon Wiese
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+trait templatable_form_element {
+
+    /**
+     * Function to export the renderer data in a format that is suitable for a
+     * mustache template. This means:
+     * 1. No complex types - only stdClass, array, int, string, float, bool
+     * 2. Any additional info that is required for the template is pre-calculated (e.g. capability checks).
+     *
+     * This trait can be used as-is for simple form elements - or imported with a different name
+     * so it can be extended with additional context variables before being returned.
+     *
+     * @param renderer_base $output Used to do a final render of any components that need to be rendered for export.
+     * @return stdClass|array
+     */
+    public function export_for_template(renderer_base $output) {
+        $context = [];
+
+        // Not all elements have all of these attributes - but they are common enough to be valid for a few.
+        $standardattributes = ['id', 'name', 'label', 'multiple', 'checked', 'error', 'size', 'value', 'type'];
+        $standardproperties = ['helpbutton', 'hiddenLabel'];
+
+        // Standard attributes.
+        foreach ($standardattributes as $attrname) {
+            $value = $this->getAttribute($attrname);
+            $context[$attrname] = $value;
+        }
+
+        // Standard class properties.
+        foreach ($standardproperties as $propname) {
+            $classpropname = '_' . $propname;
+            $context[strtolower($propname)] = isset($this->$classpropname) ? $this->$classpropname : false;
+        }
+        $extraclasses = $this->getAttribute('class');
+        $parentonlyclasses = $this->getAttribute('parentclass');
+
+        // Special wierd named property.
+        $context['frozen'] = !empty($this->_flagFrozen);
+        $context['hardfrozen'] = !empty($this->_flagFrozen) && empty($this->_persistantFreeze);
+
+        // Other attributes.
+        $otherattributes = [];
+        foreach ($this->getAttributes() as $attr => $value) {
+            if (!in_array($attr, $standardattributes) && $attr != 'class' && $attr != 'parentclass' && !is_object($value)) {
+                $otherattributes[] = $attr . '="' . s($value) . '"';
+            }
+        }
+        $context['extraclasses'] = $extraclasses;
+        $context['parentclasses'] = $parentonlyclasses;
+        $context['type'] = $this->getType();
+        $context['attributes'] = implode(' ', $otherattributes);
+        $context['emptylabel'] = ($this->getLabel() === '');
+        $context['iderror'] = preg_replace('/_id_/', '_id_error_', $context['id']);
+        $context['iderror'] = preg_replace('/^id_/', 'id_error_', $context['iderror']);
+
+        // Elements with multiple values need array syntax.
+        if ($this->getAttribute('multiple')) {
+            $context['name'] = $context['name'] . '[]';
+        }
+
+        return $context;
+    }
+}

lib/form/templates/collapsesections.mustache

@@ -0,0 +1,37 @@
+{{!
+    This file is part of Moodle - http://moodle.org/
+
+    Moodle is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Moodle is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+}}
+{{!
+    @template core_form/collapsesections
+
+    Renders a form section header
+
+    Example context (json):
+    {
+    }
+}}
+<div class="collapsible-actions">
+    <a id="collapsesections{{uniqid}}" href="#" aria-expanded="false" class="btn btn-link p-1 collapseexpand collapsemenu collapsed"{{!
+            }} role="button">
+        <span class="collapseall">{{#str}}collapseall{{/str}}</span>
+        <span class="expandall">{{#str}}expandall{{/str}}</span>
+    </a>
+</div>
+{{#js}}
+require(['core_form/collapsesections'], function(Collapsesections) {
+    Collapsesections.init('#collapsesections{{uniqid}}');
+});
+{{/js}}

lib/form/templates/editor_textarea.mustache

@@ -0,0 +1,48 @@
+{{!
+    This file is part of Moodle - http://moodle.org/
+
+    Moodle is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Moodle is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+}}
+{{!
+    @template core_form/editor_textarea
+
+    Displays an editor field in a form.
+
+    Example context (json):
+    {
+        "name": "test",
+        "id": "test0",
+        "rows": 4,
+        "cols": 20,
+        "value": "Sample text",
+        "format": 3
+    }
+}}
+<div>
+<textarea id="{{id}}" name="{{name}}[text]" class="form-control" rows="{{rows}}" cols="{{cols}}" spellcheck="true" {{#changelistener}} onblur="{{onblur}}"
+    onchange="{{onchange}}" {{/changelistener}}>{{value}}</textarea>
+</div>
+<div>
+    {{#hasformats}}
+        <label for="menu{{name}}format" class="sr-only">{{formatlabel}}</label>
+        <select name="{{name}}[format]" id="menu{{name}}format" class="custom-select">
+        {{#formats}}
+            <option value="{{value}}" {{#selected}}selected{{/selected}}>{{text}}</option>
+        {{/formats}}
+        </select>
+    {{/hasformats}}
+    {{^hasformats}}
+        <input name="{{name}}[format]" id="menu{{name}}format" type="hidden" value="{{format}}"/>
+    {{/hasformats}}
+</div>

lib/form/templates/element-advcheckbox-inline.mustache

@@ -0,0 +1,41 @@
+<label class="form-check-inline {{#error}}has-danger{{/error}} fitem {{#advanced}}advanced{{/advanced}} {{{element.extraclasses}}}">
+{{^element.hardfrozen}}
+    {{^element.frozen}}
+        <input type="hidden" name="{{element.name}}" value="{{element.deselectedvalue}}">
+    {{/element.frozen}}
+    {{#element.frozen}}
+        <input type="hidden" name="{{element.name}}" value="{{element.frozenvalue}}">
+    {{/element.frozen}}
+{{/element.hardfrozen}}
+<input type="checkbox" name="{{element.name}}" class="form-check-input {{element.extraclasses}}"
+    id="{{element.id}}"
+    {{#element.selectedvalue}}
+        value="{{element.selectedvalue}}"
+    {{/element.selectedvalue}}
+    {{#element.checked}}checked{{/element.checked}}
+    {{#error}}
+        autofocus aria-describedby="{{element.iderror}}"
+    {{/error}}
+    {{#required}}
+       aria-required="true"
+    {{/required}}
+    {{#element.frozen}}
+        disabled
+    {{/element.frozen}}
+    {{{element.attributes}}} >
+    {{{label}}}
+</label>
+{{#text}}
+    <em>{{{.}}}</em>
+{{/text}}
+{{{helpbutton}}}
+<span class="form-control-feedback invalid-feedback" id="{{element.iderror}}" {{#error}} style="display: block;"{{/error}}>
+    {{{error}}}
+</span>
+{{^element.frozen}}
+{{#js}}
+require(['theme_boost/form-display-errors'], function(module) {
+    module.enhance({{#quote}}{{element.id}}{{/quote}});
+});
+{{/js}}
+{{/element.frozen}}

lib/form/templates/element-advcheckbox.mustache

@@ -0,0 +1,71 @@
+<div class="mb-3 row {{#error}}has-danger{{/error}} fitem {{#advanced}}advanced{{/advanced}} {{{element.extraclasses}}} {{{element.parentclasses}}}">
+    <div class="col-md-3 col-form-label pb-0 pt-0">
+        {{#text}}
+            <label class="d-inline word-break" for="{{element.id}}">
+                {{{label}}}
+            </label>
+        {{/text}}
+    </div>
+    <div class="col-md-9 checkbox">
+        <div class="form-check d-flex">
+            {{^element.hardfrozen}}
+                {{^element.frozen}}
+                    <input type="hidden" name="{{element.name}}" value="{{element.deselectedvalue}}">
+                {{/element.frozen}}
+                {{#element.frozen}}
+                    <input type="hidden" name="{{element.name}}" value="{{element.frozenvalue}}">
+                {{/element.frozen}}
+            {{/element.hardfrozen}}
+            <input type="checkbox"
+                name="{{element.name}}"
+                class="form-check-input {{element.extraclasses}}"
+                {{#element.selectedvalue}}
+                    value="{{element.selectedvalue}}"
+                {{/element.selectedvalue}}
+                id="{{element.id}}" {{#element.checked}}checked{{/element.checked}}
+                {{#error}}
+                    autofocus aria-describedby="{{#text}}{{element.id}}_description {{/text}}{{element.iderror}}"
+                {{/error}}
+                {{^error}}
+                    {{#text}}
+                        aria-describedby="{{element.id}}_description"
+                    {{/text}}
+                {{/error}}
+                {{#required}}
+                   aria-required="true"
+                {{/required}}
+                {{#element.frozen}}
+                    disabled
+                {{/element.frozen}}
+                {{{element.attributes}}} >
+            {{#text}}
+                <span id="{{element.id}}_description">
+                    {{{.}}}
+                </span>
+            {{/text}}
+            {{^text}}
+                <label for="{{element.id}}">
+                    {{{label}}}
+                </label>
+            {{/text}}
+            <div class="ml-2 d-flex align-items-center align-self-start">
+                {{#required}}
+                    <div class="text-danger" title="{{#str}}required{{/str}}">
+                    {{#pix}}req, core, {{#str}}required{{/str}}{{/pix}}
+                    </div>
+                {{/required}}
+                {{{helpbutton}}}
+            </div>
+        </div>
+        <div class="form-control-feedback invalid-feedback" id="{{element.iderror}}" {{#error}} style="display: block;"{{/error}}>
+            {{{error}}}
+        </div>
+    </div>
+</div>
+{{^element.frozen}}
+{{#js}}
+require(['theme_boost/form-display-errors'], function(module) {
+    module.enhance({{#quote}}{{element.id}}{{/quote}});
+});
+{{/js}}
+{{/element.frozen}}

lib/form/templates/element-autocomplete-inline.mustache

@@ -0,0 +1,46 @@
+{{< core_form/element-template-inline }}
+    {{$element}}
+        {{^element.frozen}}
+        {{#element.multiple}}
+            <input type="hidden" name="{{element.nameraw}}" value="_qf__force_multiselect_submission">
+        {{/element.multiple}}
+        <select class="custom-select {{#error}}is-invalid{{/error}}" name="{{element.name}}"
+            id="{{element.id}}"
+            {{#element.multiple}}multiple{{/element.multiple}}
+            {{#error}}
+                autofocus aria-describedby="{{element.iderror}}"
+            {{/error}}
+            {{#required}}
+                aria-required="true"
+            {{/required}}
+            {{{element.attributes}}} >
+            {{#element.options}}
+            <option value="{{value}}" {{#selected}}selected{{/selected}}{{#html}} data-html="{{html}}"{{/html}}>{{{text}}}</option>
+            {{/element.options}}
+        </select>
+        {{/element.frozen}}
+        {{#element.frozen}}
+            {{#element.options}}
+                {{#selected}}
+                    {{{text}}}
+                    {{^element.hardfrozen}}
+                        <input type="hidden" name="{{element.name}}" value="{{value}}">
+                    {{/element.hardfrozen}}
+                {{/selected}}
+            {{/element.options}}
+        {{/element.frozen}}
+    {{/element}}
+{{/ core_form/element-template-inline }}
+{{^element.frozen}}
+{{#js}}
+require(['core/form-autocomplete'], function(module) {
+    module.enhance({{#quote}}#{{element.id}}{{/quote}},
+                   {{element.tags}},
+                   {{#quote}}{{element.ajax}}{{/quote}},
+                   {{#quote}}{{element.placeholder}}{{/quote}},
+                   {{element.casesensitive}},
+                   {{element.showsuggestions}},
+                   {{#quote}}{{element.noselectionstring}}{{/quote}});
+});
+{{/js}}
+{{/element.frozen}}

lib/form/templates/element-autocomplete.mustache

@@ -0,0 +1,46 @@
+{{< core_form/element-template }}
+    {{$element}}
+        {{^element.frozen}}
+        {{#element.multiple}}
+            <input type="hidden" name="{{element.nameraw}}" value="_qf__force_multiselect_submission">
+        {{/element.multiple}}
+        <select class="custom-select {{#error}}is-invalid{{/error}}" name="{{element.name}}"
+            id="{{element.id}}"
+            {{#element.multiple}}multiple{{/element.multiple}}
+            {{#error}}
+                autofocus aria-describedby="{{element.iderror}}"
+            {{/error}}
+            {{#required}}
+                aria-required="true"
+            {{/required}}
+            {{{element.attributes}}} >
+            {{#element.options}}
+            <option value="{{value}}" {{#selected}}selected{{/selected}}{{#html}} data-html="{{html}}"{{/html}}>{{{text}}}</option>
+            {{/element.options}}
+        </select>
+        {{/element.frozen}}
+        {{#element.frozen}}
+            {{#element.options}}
+                {{#selected}}
+                    {{{text}}}
+                    {{^element.hardfrozen}}
+                        <input type="hidden" name="{{element.name}}" value="{{value}}">
+                    {{/element.hardfrozen}}
+                {{/selected}}
+            {{/element.options}}
+        {{/element.frozen}}
+    {{/element}}
+{{/ core_form/element-template }}
+{{^element.frozen}}
+{{#js}}
+require(['core/form-autocomplete'], function(module) {
+    module.enhance({{#quote}}#{{element.id}}{{/quote}},
+                   {{element.tags}},
+                   {{#quote}}{{element.ajax}}{{/quote}},
+                   {{#quote}}{{element.placeholder}}{{/quote}},
+                   {{element.casesensitive}},
+                   {{element.showsuggestions}},
+                   {{#quote}}{{element.noselectionstring}}{{/quote}});
+});
+{{/js}}
+{{/element.frozen}}

lib/form/templates/element-button-inline.mustache

@@ -0,0 +1,20 @@
+{{< core_form/element-template-inline }}
+    {{$element}}
+        {{^element.frozen}}
+            <button
+                class="btn
+                {{^element.customclassoverride}}btn-secondary{{/element.customclassoverride}}
+                {{#element.customclassoverride}}{{.}}{{/element.customclassoverride}}"
+                name="{{element.name}}"
+                id="{{element.id}}"
+                type="button"
+                {{#error}}
+                    autofocus aria-describedby="{{element.iderror}}"
+                {{/error}}
+                {{{element.attributes}}}
+                >
+                {{{element.value}}}
+            </button>
+        {{/element.frozen}}
+    {{/element}}
+{{/ core_form/element-template-inline }}

lib/form/templates/element-button.mustache

@@ -0,0 +1,19 @@
+{{< core_form/element-template }}
+    {{$element}}
+        {{^element.frozen}}
+        <button
+                class="btn
+                {{^element.customclassoverride}}btn-secondary ml-0{{/element.customclassoverride}}
+                {{#element.customclassoverride}}{{.}}{{/element.customclassoverride}}"
+                name="{{element.name}}"
+                id="{{element.id}}"
+                type="button"
+                {{#error}}
+                    autofocus aria-describedby="{{element.iderror}}"
+                {{/error}}
+                {{{element.attributes}}}>
+                {{{element.value}}}
+                </button>
+        {{/element.frozen}}
+    {{/element}}
+{{/ core_form/element-template }}

lib/form/templates/element-checkbox-inline.mustache

@@ -0,0 +1,41 @@
+<label data-fieldtype="checkbox" class="form-check {{#error}}has-danger{{/error}} fitem {{#advanced}}advanced{{/advanced}} {{{element.extraclasses}}}">
+{{^element.hardfrozen}}
+    {{#element.frozen}}
+        <input type="hidden" name="{{element.name}}" value="{{element.frozenvalue}}">
+    {{/element.frozen}}
+{{/element.hardfrozen}}
+<input type="checkbox" name="{{element.name}}" class="form-check-input {{element.extraclasses}}"
+    id="{{element.id}}"
+    {{#element.value}}
+        value="{{element.value}}"
+    {{/element.value}}
+    {{^element.value}}
+        value="1"
+    {{/element.value}}
+    {{#element.checked}}checked{{/element.checked}}
+    {{#error}}
+        autofocus aria-describedby="{{element.iderror}}"
+    {{/error}}
+    {{#required}}
+       aria-required="true"
+    {{/required}}
+    {{#element.frozen}}
+        disabled
+    {{/element.frozen}}
+    {{{element.attributes}}} >
+    {{{label}}}
+</label>
+{{#text}}
+    <em>{{{.}}}</em>
+{{/text}}
+{{{helpbutton}}}
+<span class="form-control-feedback invalid-feedback" id="{{element.iderror}}" {{#error}} style="display: block;"{{/error}}>
+    {{{error}}}
+</span>
+{{^element.frozen}}
+{{#js}}
+require(['theme_boost/form-display-errors'], function(module) {
+    module.enhance({{#quote}}{{element.id}}{{/quote}});
+});
+{{/js}}
+{{/element.frozen}}

lib/form/templates/element-checkbox.mustache

@@ -0,0 +1,72 @@
+<div class="mb-3 row {{#error}}has-danger{{/error}} fitem {{#advanced}}advanced{{/advanced}} {{{element.extraclasses}}} {{{element.parentclasses}}}">
+    <div class="col-md-3 col-form-label pb-0 pt-0">
+        {{#text}}
+            <label class="d-inline word-break" for="{{element.id}}">
+                {{{label}}}
+            </label>
+        {{/text}}
+    </div>
+    <div class="col-md-9 checkbox">
+        <div class="form-check d-flex">
+            {{^element.hardfrozen}}
+                {{#element.frozen}}
+                    <input type="hidden" name="{{element.name}}" value="{{element.frozenvalue}}">
+                {{/element.frozen}}
+            {{/element.hardfrozen}}
+            <input type="checkbox"
+                name="{{element.name}}"
+                class="form-check-input {{element.extraclasses}}"
+                {{#element.value}}
+                    value="{{element.value}}"
+                {{/element.value}}
+                {{^element.value}}
+                    value="1"
+                {{/element.value}}
+                id="{{element.id}}" {{#element.checked}}checked{{/element.checked}}
+                {{#error}}
+                    autofocus aria-describedby="{{#text}}{{element.id}}_description {{/text}}{{element.iderror}}"
+                {{/error}}
+                {{^error}}
+                    {{#text}}
+                        aria-describedby="{{element.id}}_description"
+                    {{/text}}
+                {{/error}}
+                {{#required}}
+                   aria-required="true"
+                {{/required}}
+                {{#element.frozen}}
+                    disabled
+                {{/element.frozen}}
+                {{{element.attributes}}} >
+            {{#text}}
+                <span id="{{element.id}}_description">
+                    {{{.}}}
+                </span>
+            {{/text}}
+            {{^text}}
+                <label for="{{element.id}}">
+                    {{{label}}}
+                </label>
+            {{/text}}
+            <div class="ml-2 d-flex align-items-center align-self-start">
+                {{#required}}
+                    <div class="text-danger" title="{{#str}}required{{/str}}">
+                    {{#pix}}req, core, {{#str}}required{{/str}}{{/pix}}
+                    </div>
+                {{/required}}
+                {{{helpbutton}}}
+            </div>
+        </div>
+        <div class="form-control-feedback invalid-feedback" id="{{element.iderror}}" {{#error}} style="display: block;"{{/error}}>
+            {{{error}}}
+        </div>
+    </div>
+</div>
+{{^element.frozen}}
+
+{{#js}}
+require(['theme_boost/form-display-errors'], function(module) {
+    module.enhance({{#quote}}{{element.id}}{{/quote}});
+});
+{{/js}}
+{{/element.frozen}}