first commit

question/classes/local/bank/action_column_base.php

@@ -0,0 +1,93 @@
+<?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/>.
+
+/**
+ * A base class for actions that are an icon that lets you manipulate the question in some way.
+ *
+ * @package   core_question
+ * @copyright 2009 Tim Hunt
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\local\bank;
+
+/**
+ * A base class for actions that are an icon that lets you manipulate the question in some way.
+ *
+ * @copyright 2009 Tim Hunt
+ * @author    2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @deprecated Since Moodle 4.3 MDL-75125 - Use question_action_base instead.
+ * @todo MDL-78090 This class will be deleted in Moodle 4.7
+ */
+abstract class action_column_base extends column_base {
+
+    /**
+     * @return string
+     * @deprecated Since Moodle 4.3
+     */
+    public function get_title(): string {
+        debugging('The action_column_base class is deprecated. Please use question_action_base instead.', DEBUG_DEVELOPER);
+        return '&#160;';
+    }
+
+    /**
+     * @return string[]
+     * @deprecated Since Moodle 4.3
+     */
+    public function get_extra_classes(): array {
+        debugging('The action_column_base class is deprecated. Please use question_action_base instead.', DEBUG_DEVELOPER);
+
+        return ['iconcol'];
+    }
+
+    /**
+     * @param $icon
+     * @param $title
+     * @param $url
+     * @return void
+     * @deprecated Since Moodle 4.3
+     */
+    protected function print_icon($icon, $title, $url): void {
+        debugging('The action_column_base class is deprecated. Please use question_action_base instead.', DEBUG_DEVELOPER);
+        global $OUTPUT;
+        echo \html_writer::tag('a', $OUTPUT->pix_icon($icon, $title), ['title' => $title, 'href' => $url]);
+    }
+
+    /**
+     * @return string[]
+     * @deprecated Since Moodle 4.3
+     */
+    public function get_extra_joins(): array {
+        debugging('The action_column_base class is deprecated. Please use question_action_base instead.', DEBUG_DEVELOPER);
+        return ['qv' => 'JOIN {question_versions} qv ON qv.questionid = q.id',
+                'qbe' => 'JOIN {question_bank_entries} qbe on qbe.id = qv.questionbankentryid',
+                'qc' => 'JOIN {question_categories} qc ON qc.id = qbe.questioncategoryid'];
+    }
+
+    /**
+     * @return string[]
+     * @deprecated Since Moodle 4.3
+     */
+    public function get_required_fields(): array {
+        debugging('The action_column_base class is deprecated. Please use question_action_base instead.', DEBUG_DEVELOPER);
+        // Createdby is required for permission checks.
+        // Qtype so we can easily avoid applying actions to question types that
+        // are no longer installed.
+        return ['q.id', 'q.qtype', 'q.createdby', 'qc.contextid'];
+    }
+
+}

question/classes/local/bank/bulk_action_base.php

@@ -0,0 +1,78 @@
+<?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_question\local\bank;
+
+/**
+ * Class bulk_action_base is the base class for bulk actions ui.
+ *
+ * Every plugin wants to implement a bulk action, should extend this class, add appropriate values to the methods
+ * and finally pass this object via plugin_feature class.
+ *
+ * @package    core_question
+ * @copyright  2021 Catalyst IT Australia Pty Ltd
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+abstract class bulk_action_base {
+
+    /**
+     * Title of the bulk action.
+     * Every bulk action will have a string to show in the list.
+     *
+     * @return string
+     */
+    abstract public function get_bulk_action_title(): string;
+
+    /**
+     * A unique key for the bulk action, this will be used in the api to identify the action data.
+     * Every bulk must have a unique key to perform the action as a part of the form post in the base view.
+     * When questions are selected, it will post according to the key its selected from the dropdown.
+     *
+     * @return string
+     */
+    abstract function get_key(): string;
+
+    /**
+     * URL of the bulk action redirect page.
+     * Bulk action can be performed by redirecting to a page and doing the appropriate selection
+     * and finally doing the action. The url will be url of the page where users will be redirected to
+     * select what to do with the selected questions.
+     *
+     * @return \moodle_url
+     */
+    abstract public function get_bulk_action_url(): \moodle_url;
+
+    /**
+     * Get the capabilities for the bulk action.
+     * The bulk actions might have some capabilities to action them as a user.
+     * This method helps to get those caps which will be used by the base view before actioning the bulk action.
+     * For ex: ['moodle/question:moveall', 'moodle/question:add']
+     * At least one of the cap need to be true for the user to use this action.
+     *
+     * @return array|null
+     */
+    public function get_bulk_action_capabilities(): ?array {
+        return null;
+    }
+
+    /**
+     * @deprecated since Moodle 4.0
+     */
+    public function get_bulk_action_key() {
+        throw new \coding_exception(__FUNCTION__ . '() has been removed.');
+    }
+}

question/classes/local/bank/checkbox_column.php

@@ -0,0 +1,102 @@
+<?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/>.
+
+/**
+ * A column with a checkbox for each question with name q{questionid}.
+ *
+ * @package   core_question
+ * @copyright 2009 Tim Hunt
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\local\bank;
+
+use core\output\checkbox_toggleall;
+
+/**
+ * A column with a checkbox for each question with name q{questionid}.
+ *
+ * @copyright 2009 Tim Hunt
+ * @author    2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class checkbox_column extends column_base {
+
+    public function get_name(): string {
+        return 'checkbox';
+    }
+
+    public function get_title() {
+        global $OUTPUT;
+
+        $mastercheckbox = new checkbox_toggleall('qbank', true, [
+            'id' => 'qbheadercheckbox',
+            'name' => 'qbheadercheckbox',
+            'value' => '1',
+            'label' => get_string('selectall'),
+            'labelclasses' => 'accesshide',
+        ]);
+
+        return $OUTPUT->render($mastercheckbox);
+    }
+
+    public function get_title_tip() {
+        return get_string('selectquestionsforbulk', 'question');
+    }
+
+    public function display_header(array $columnactions = [], string $width = ''): void {
+        global $PAGE;
+        $renderer = $PAGE->get_renderer('core_question', 'bank');
+
+        $data = [];
+        $data['sortable'] = false;
+        $data['extraclasses'] = $this->get_classes();
+        $name = get_class($this);
+        $data['sorttip'] = true;
+        $data['tiptitle'] = $this->get_title();
+        $data['tip'] = $this->get_title_tip();
+
+        $data['colname'] = $this->get_column_name();
+        $data['columnid'] = $this->get_column_id();
+        $data['name'] = get_string('selectall');
+        $data['class'] = $name;
+        $data['width'] = $width;
+
+        echo $renderer->render_column_header($data);
+    }
+
+    protected function display_content($question, $rowclasses): void {
+        global $OUTPUT;
+
+        $checkbox = new checkbox_toggleall('qbank', false, [
+            'id' => "checkq{$question->id}",
+            'name' => "q{$question->id}",
+            'value' => '1',
+            'label' => get_string('select'),
+            'labelclasses' => 'accesshide',
+        ]);
+
+        echo $OUTPUT->render($checkbox);
+    }
+
+    public function get_required_fields(): array {
+        return ['q.id'];
+    }
+
+    public function get_default_width(): int {
+        return 30;
+    }
+}

question/classes/local/bank/column_action_base.php

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+<?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_question\local\bank;
+
+/**
+ * Base class to implement actions that can be performed on any column.
+ *
+ * A plugin should define subclasses of this for each action it provides, and return an instance of each from
+ * plugin_feature::get_column_actions(). The action returned from {@see get_action_menu_link()} will be displayed in each column
+ * header.
+ *
+ * @package   core_question
+ * @copyright 2023 onwards Catalyst IT EU {@link https://catalyst-eu.net}
+ * @author    Mark Johnson <mark.johnson@catalyst-eu.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+abstract class column_action_base extends view_component {
+    /**
+     * A chance for subclasses to initialise themselves, for example to load lang strings,
+     * without having to override the constructor.
+     */
+    protected function init(): void {
+    }
+
+    /**
+     * Return the action menu link for this action on the supplied column.
+     *
+     * @param column_base $column The column we are providing the action for.
+     * @return ?\action_menu_link The action to display in the column header.
+     */
+    abstract public function get_action_menu_link(column_base $column): ?\action_menu_link;
+}

question/classes/local/bank/column_base.php

@@ -0,0 +1,477 @@
+<?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/>.
+
+/**
+ * Base class for representing a column.
+ *
+ * @package   core_question
+ * @copyright 1999 onwards Martin Dougiamas and others {@link http://moodle.com}
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\local\bank;
+
+/**
+ * Base class for representing a column.
+ *
+ * @copyright 2009 Tim Hunt
+ * @author    2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+abstract class column_base extends view_component {
+
+    /**
+     * @var string A separator for joining column attributes together into a unique ID string.
+     */
+    const ID_SEPARATOR = '-';
+
+    /**
+     * @var view $qbank the question bank view we are helping to render.
+     */
+    protected $qbank;
+
+    /** @var bool determine whether the column is td or th. */
+    protected $isheading = false;
+
+    /** @var bool determine whether the column is visible */
+    public $isvisible = true;
+
+    /**
+     * Return an instance of this column, based on the column name.
+     *
+     * In the case of the base class, we don't actually use the column name since the class represents one specific column.
+     * However, sub-classes may use the column name as an additional constructor to the parameter.
+     *
+     * @param view $view Question bank view
+     * @param string $columnname The column name for this instance, as returned by {@see get_column_name()}
+     * @param bool $ingoremissing Whether to ignore if the class does not exist.
+     * @return column_base|null An instance of this class.
+     */
+    public static function from_column_name(view $view, string $columnname, bool $ingoremissing = false): ?column_base {
+        return new static($view);
+    }
+
+    /**
+     * Set the column as heading
+     */
+    public function set_as_heading(): void {
+        $this->isheading = true;
+    }
+
+    /**
+     * Check if the column is an extra row of not.
+     */
+    public function is_extra_row(): bool {
+        return false;
+    }
+
+    /**
+     * Check if the row has an extra preference to view/hide.
+     */
+    public function has_preference(): bool {
+        return false;
+    }
+
+    /**
+     * Get if the preference key of the row.
+     */
+    public function get_preference_key(): string {
+        return '';
+    }
+
+    /**
+     * Get if the preference of the row.
+     */
+    public function get_preference(): bool {
+        return false;
+    }
+
+    /**
+     * Output the column header cell.
+     *
+     * @param column_action_base[] $columnactions A list of column actions to include in the header.
+     * @param string $width A CSS width property value.
+     */
+    public function display_header(array $columnactions = [], string $width = ''): void {
+        global $PAGE;
+        $renderer = $PAGE->get_renderer('core_question', 'bank');
+
+        $data = [];
+        $data['sortable'] = true;
+        $data['extraclasses'] = $this->get_classes();
+        $sortable = $this->is_sortable();
+        $name = str_replace('\\', '__', get_class($this));
+        $title = $this->get_title();
+        $tip = $this->get_title_tip();
+        $links = [];
+        if (is_array($sortable)) {
+            if ($title) {
+                $data['title'] = $title;
+            }
+            foreach ($sortable as $subsort => $details) {
+                $links[] = $this->make_sort_link($name . '-' . $subsort,
+                        $details['title'], isset($details['tip']) ? $details['tip'] : '', !empty($details['reverse']));
+            }
+            $data['sortlinks'] = implode(' / ', $links);
+        } else if ($sortable) {
+            $data['sortlinks'] = $this->make_sort_link($name, $title, $tip);
+        } else {
+            $data['sortable'] = false;
+            $data['tiptitle'] = $title;
+            if ($tip) {
+                $data['sorttip'] = true;
+                $data['tip'] = $tip;
+            }
+        }
+        $help = $this->help_icon();
+        if ($help) {
+            $data['help'] = $help->export_for_template($renderer);
+        }
+
+        $data['colname'] = $this->get_column_name();
+        $data['columnid'] = $this->get_column_id();
+        $data['name'] = $title;
+        $data['class'] = $name;
+        $data['width'] = $width;
+        if (!empty($columnactions)) {
+            $actions = array_map(fn($columnaction) => $columnaction->get_action_menu_link($this), $columnactions);
+            $actionmenu = new \action_menu($actions);
+            $data['actionmenu'] = $actionmenu->export_for_template($renderer);
+        }
+
+        echo $renderer->render_column_header($data);
+    }
+
+    /**
+     * Title for this column. Not used if is_sortable returns an array.
+     */
+    abstract public function get_title();
+
+    /**
+     * Use this when get_title() returns
+     * something very short, and you want a longer version as a tool tip.
+     *
+     * @return string a fuller version of the name.
+     */
+    public function get_title_tip() {
+        return '';
+    }
+
+    /**
+     * If you return a help icon here, it is shown in the column header after the title.
+     *
+     * @return \help_icon|null help icon to show, if required.
+     */
+    public function help_icon(): ?\help_icon {
+        return null;
+    }
+
+    /**
+     * Get a link that changes the sort order, and indicates the current sort state.
+     *
+     * @param string $sortname the column to sort on.
+     * @param string $title the link text.
+     * @param string $tip the link tool-tip text. If empty, defaults to title.
+     * @param bool $defaultreverse whether the default sort order for this column is descending, rather than ascending.
+     * @return string
+     */
+    protected function make_sort_link($sortname, $title, $tip, $defaultreverse = false): string {
+        global $PAGE;
+        $sortdata = [];
+        $currentsort = $this->qbank->get_primary_sort_order($sortname);
+        $newsortreverse = $defaultreverse;
+        if ($currentsort) {
+            $newsortreverse = $currentsort == SORT_ASC;
+        }
+        if (!$tip) {
+            $tip = $title;
+        }
+        if ($newsortreverse) {
+            $tip = get_string('sortbyxreverse', '', $tip);
+        } else {
+            $tip = get_string('sortbyx', '', $tip);
+        }
+
+        $link = $title;
+        if ($currentsort) {
+            $link .= $this->get_sort_icon($currentsort == SORT_DESC);
+        }
+
+        $sortdata['sorturl'] = $this->qbank->new_sort_url($sortname, $newsortreverse);
+        $sortdata['sortname'] = $sortname;
+        $sortdata['sortcontent'] = $link;
+        $sortdata['sorttip'] = $tip;
+        $sortdata['sortorder'] = $newsortreverse ? SORT_DESC : SORT_ASC;
+        $renderer = $PAGE->get_renderer('core_question', 'bank');
+        return $renderer->render_column_sort($sortdata);
+
+    }
+
+    /**
+     * Get an icon representing the corrent sort state.
+     * @param bool $reverse sort is descending, not ascending.
+     * @return string HTML image tag.
+     */
+    protected function get_sort_icon($reverse): string {
+        global $OUTPUT;
+        if ($reverse) {
+            return $OUTPUT->pix_icon('t/sort_desc', get_string('desc'), '', ['class' => 'iconsort']);
+        } else {
+            return $OUTPUT->pix_icon('t/sort_asc', get_string('asc'), '', ['class' => 'iconsort']);
+        }
+    }
+
+    /**
+     * Output this column.
+     * @param object $question the row from the $question table, augmented with extra information.
+     * @param string $rowclasses CSS class names that should be applied to this row of output.
+     */
+    public function display($question, $rowclasses): void {
+        $this->display_start($question, $rowclasses);
+        $this->display_content($question, $rowclasses);
+        $this->display_end($question, $rowclasses);
+    }
+
+    /**
+     * Output the opening column tag.  If it is set as heading, it will use <th> tag instead of <td>
+     *
+     * @param \stdClass $question
+     * @param string $rowclasses
+     */
+    protected function display_start($question, $rowclasses): void {
+        $tag = 'td';
+        $attr = [
+            'class' => $this->get_classes(),
+            'data-columnid' => $this->get_column_id(),
+        ];
+        if ($this->isheading) {
+            $tag = 'th';
+            $attr['scope'] = 'row';
+        }
+        echo \html_writer::start_tag($tag, $attr);
+    }
+
+    /**
+     * The CSS classes to apply to every cell in this column.
+     *
+     * @return string
+     */
+    protected function get_classes(): string {
+        $classes = $this->get_extra_classes();
+        $classes[] = $this->get_name();
+        return implode(' ', $classes);
+    }
+
+    /**
+     * Get the internal name for this column. Used as a CSS class name,
+     * and to store information about the current sort. Must match PARAM_ALPHA.
+     *
+     * @return string column name.
+     */
+    abstract public function get_name();
+
+    /**
+     * Get the name of this column. This must be unique.
+     * When using the inherited class to make many columns from one parent,
+     * ensure each instance returns a unique value.
+     *
+     * @return string The unique name;
+     */
+    public function get_column_name() {
+        return (new \ReflectionClass($this))->getShortName();
+    }
+
+    /**
+     * Return a unique ID for this column object.
+     *
+     * This is constructed using the class name and get_column_name(), which must be unique.
+     *
+     * The combination of these attributes allows the object to be reconstructed, by splitting the ID into its constituent
+     * parts then calling {@see from_column_name()}, like this:
+     * [$class, $columnname] = explode(column_base::ID_SEPARATOR, $columnid, 2);
+     * $column = $class::from_column_name($qbank, $columnname);
+     * Including 2 as the $limit parameter for explode() is a good idea for safely, in case a plugin defines a column with the
+     * ID_SEPARATOR in the column name.
+     *
+     * @return string The column ID.
+     */
+    final public function get_column_id(): string {
+        return implode(self::ID_SEPARATOR, [static::class, $this->get_column_name()]);
+    }
+
+    /**
+     * Any extra class names you would like applied to every cell in this column.
+     *
+     * @return array
+     */
+    public function get_extra_classes(): array {
+        return [];
+    }
+
+    /**
+     * Return the default column width in pixels.
+     *
+     * @return int
+     */
+    public function get_default_width(): int {
+        return 120;
+    }
+
+    /**
+     * Output the contents of this column.
+     * @param object $question the row from the $question table, augmented with extra information.
+     * @param string $rowclasses CSS class names that should be applied to this row of output.
+     */
+    abstract protected function display_content($question, $rowclasses);
+
+    /**
+     * Output the closing column tag
+     *
+     * @param object $question
+     * @param string $rowclasses
+     */
+    protected function display_end($question, $rowclasses): void {
+        $tag = 'td';
+        if ($this->isheading) {
+            $tag = 'th';
+        }
+        echo \html_writer::end_tag($tag);
+    }
+
+    public function get_extra_joins(): array {
+        return [];
+    }
+
+    public function get_required_fields(): array {
+        return [];
+    }
+
+    /**
+     * If this column requires any aggregated statistics, it should declare that here.
+     *
+     * This is those statistics can be efficiently loaded in bulk.
+     *
+     * The statistics are all loaded just before load_additional_data is called on each column.
+     * The values are then available from $this->qbank->get_aggregate_statistic(...);
+     *
+     * @return string[] the names of the required statistics fields. E.g. ['facility'].
+     */
+    public function get_required_statistics_fields(): array {
+        return [];
+    }
+
+    /**
+     * If this column needs extra data (e.g. tags) then load that here.
+     *
+     * The extra data should be added to the question object in the array.
+     * Probably a good idea to check that another column has not already
+     * loaded the data you want.
+     *
+     * @param \stdClass[] $questions the questions that will be displayed, indexed by question id.
+     */
+    public function load_additional_data(array $questions) {
+    }
+
+    /**
+     * Load the tags for each question.
+     *
+     * Helper that can be used from {@see load_additional_data()};
+     *
+     * @param array $questions
+     */
+    public function load_question_tags(array $questions): void {
+        $firstquestion = reset($questions);
+        if (isset($firstquestion->tags)) {
+            // Looks like tags are already loaded, so don't do it again.
+            return;
+        }
+
+        // Load the tags.
+        $tagdata = \core_tag_tag::get_items_tags('core_question', 'question',
+                array_keys($questions));
+
+        // Add them to the question objects.
+        foreach ($tagdata as $questionid => $tags) {
+            $questions[$questionid]->tags = $tags;
+        }
+    }
+
+    /**
+     * Can this column be sorted on? You can return either:
+     *  + false for no (the default),
+     *  + a field name, if sorting this column corresponds to sorting on that datbase field.
+     *  + an array of subnames to sort on as follows
+     *  return [
+     *      'firstname' => ['field' => 'uc.firstname', 'title' => get_string('firstname')],
+     *      'lastname' => ['field' => 'uc.lastname', 'title' => get_string('lastname')],
+     *  ];
+     * As well as field, and field, you can also add 'revers' => 1 if you want the default sort
+     * order to be DESC.
+     * @return mixed as above.
+     */
+    public function is_sortable() {
+        return false;
+    }
+
+    /**
+     * Helper method for building sort clauses.
+     * @param bool $reverse whether the normal direction should be reversed.
+     * @return string 'ASC' or 'DESC'
+     */
+    protected function sortorder($reverse): string {
+        if ($reverse) {
+            return ' DESC';
+        } else {
+            return ' ASC';
+        }
+    }
+
+    /**
+     * Sorts the expressions.
+     *
+     * @param bool $reverse Whether to sort in the reverse of the default sort order.
+     * @param string $subsort if is_sortable returns an array of subnames, then this will be
+     *      one of those. Otherwise will be empty.
+     * @return string some SQL to go in the order by clause.
+     */
+    public function sort_expression($reverse, $subsort): string {
+        $sortable = $this->is_sortable();
+        if (is_array($sortable)) {
+            if (array_key_exists($subsort, $sortable)) {
+                return $sortable[$subsort]['field'] . $this->sortorder($reverse);
+            } else {
+                throw new \coding_exception('Unexpected $subsort type: ' . $subsort);
+            }
+        } else if ($sortable) {
+            return $sortable . $this->sortorder($reverse);
+        } else {
+            throw new \coding_exception('sort_expression called on a non-sortable column.');
+        }
+    }
+
+    /**
+     * Output the column with an example value.
+     *
+     * By default, this will call $this->display() using whatever dummy data is passed in. Columns can override this
+     * to provide example output without requiring valid data.
+     *
+     * @param \stdClass $question the row from the $question table, augmented with extra information.
+     * @param string $rowclasses CSS class names that should be applied to this row of output.
+     */
+    public function display_preview(\stdClass $question, string $rowclasses): void {
+        $this->display($question, $rowclasses);
+    }
+}

question/classes/local/bank/column_manager_base.php

@@ -0,0 +1,73 @@
+<?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_question\local\bank;
+
+/**
+ * Default column manager class
+ *
+ * This class defines stub methods that can be overridden by a plugin defining its own column manager.
+ *
+ * @package   core_question
+ * @copyright 2023 onwards Catalyst IT EU {@link https://catalyst-eu.net}
+ * @author    Mark Johnson <mark.johnson@catalyst-eu.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class column_manager_base {
+    /**
+     * Sort the list of columns
+     *
+     * Sort the provided list of columns into the order implemented in this column manager.
+     *
+     * @param array $unsortedcolumns Unordered array of columns
+     * @return array Columns in the desired order.
+     */
+    public function get_sorted_columns(array $unsortedcolumns): array {
+        return $unsortedcolumns;
+    }
+
+    /**
+     * Given an array of columns, set the isvisible attribute.
+     *
+     * This base class leave all columns visible.
+     *
+     * @param column_base[] $columns
+     * @return array
+     */
+    public function set_columns_visibility(array $columns): array {
+        return $columns;
+    }
+
+    /**
+     * Return a list of actions to display in an action menu for each column.
+     *
+     * @param view $qbank Question bank view.
+     * @return column_action_base[] A list of column actions.
+     */
+    public function get_column_actions(view $qbank): array {
+        return [];
+    }
+
+    /**
+     * Given a column, return a value for its width CSS property.
+     *
+     * @param column_base $column
+     * @return string CSS width property value.
+     */
+    public function get_column_width(column_base $column): string {
+        return $column->get_default_width() . 'px';
+    }
+}

question/classes/local/bank/condition.php

@@ -0,0 +1,222 @@
+<?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_question\local\bank;
+
+use core\output\datafilter;
+
+/**
+ * An abstract class for filtering/searching questions.
+ *
+ * @package    core_question
+ * @copyright  2013 Ray Morris
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+abstract class condition {
+
+    /** @var int The default filter type */
+    const JOINTYPE_DEFAULT = datafilter::JOINTYPE_ANY;
+
+    /** @var ?array Filter properties for this condition. */
+    public ?array $filter;
+
+    /** @var string SQL fragment to add to the where clause. */
+    protected string $where = '';
+
+    /** @var array query param used in where. */
+    protected array $params = [];
+
+    /**
+     * Return title of the condition
+     *
+     * @return string title of the condition
+     */
+    abstract public function get_title();
+
+    /**
+     * Return filter class associated with this condition
+     *
+     * @return string filter class
+     */
+    abstract public function get_filter_class();
+
+    /**
+     * Extract the required filter from the provided question bank view.
+     *
+     * This will look for the filter matching {@see get_condition_key()}
+     *
+     * @param view|null $qbank
+     */
+    public function __construct(view $qbank = null) {
+        if (is_null($qbank)) {
+            return;
+        }
+        $this->filter = static::get_filter_from_list($qbank->get_pagevars('filter'));
+        // Build where and params.
+        [$this->where, $this->params] = $this->filter ? static::build_query_from_filter($this->filter) : ['', []];
+    }
+
+    /**
+     * Whether customisation is allowed.
+     *
+     * @return bool
+     */
+    public function allow_custom() {
+        return true;
+    }
+
+    /**
+     * Whether multiple values are allowed .
+     *
+     * @return bool
+     */
+    public function allow_multiple() {
+        return true;
+    }
+
+    /**
+     * Initial values of the condition
+     *
+     * @return array
+     */
+    public function get_initial_values() {
+        return [];
+    }
+
+    /**
+     * Extra data specific to this condition.
+     *
+     * @return \stdClass
+     */
+    public function get_filteroptions(): \stdClass {
+        return (object)[];
+    }
+
+    /**
+     * Whether empty value is allowed
+     *
+     * @return bool
+     */
+    public function allow_empty() {
+        return true;
+    }
+
+    /**
+     * Whether this filter is required - if so it cannot be removed from the list of filters.
+     *
+     * @return bool
+     */
+    public function is_required(): bool {
+        return false;
+    }
+
+    /**
+     * Return this condition class
+     *
+     * @return string
+     */
+    public function get_condition_class() {
+        return get_class($this);
+    }
+
+    /**
+     * Each condition will need a unique key to be identified and sequenced by the api.
+     * Use a unique string for the condition identifier, use string directly, dont need to use language pack.
+     * Using language pack might break the filter object for multilingual support.
+     *
+     * @return string
+     */
+    public static function get_condition_key() {
+        return '';
+    }
+
+    /**
+     * Return an SQL fragment to be ANDed into the WHERE clause to filter which questions are shown.
+     *
+     * @return string SQL fragment. Must use named parameters.
+     */
+    public function where() {
+        return $this->where;
+    }
+
+    /**
+     * Return parameters to be bound to the above WHERE clause fragment.
+     * @return array parameter name => value.
+     */
+    public function params() {
+        return $this->params;
+    }
+
+    /**
+     * Display GUI for selecting criteria for this condition. Displayed when Show More is open.
+     *
+     * Compare display_options(), which displays always, whether Show More is open or not.
+     * @return bool|string HTML form fragment
+     * @deprecated since Moodle 4.0 MDL-72321 - please do not use this function any more.
+     * @todo Final deprecation on Moodle 4.1 MDL-72572
+     */
+    public function display_options_adv() {
+        debugging('Function display_options_adv() is deprecated, please use filtering objects', DEBUG_DEVELOPER);
+        return false;
+    }
+
+    /**
+     * Display GUI for selecting criteria for this condition. Displayed always, whether Show More is open or not.
+     *
+     * Compare display_options_adv(), which displays when Show More is open.
+     * @return bool|string HTML form fragment
+     * @deprecated since Moodle 4.0 MDL-72321 - please do not use this function any more.
+     * @todo Final deprecation on Moodle 4.1 MDL-72572
+     */
+    public function display_options() {
+        debugging('Function display_options() is deprecated, please use filtering objects', DEBUG_DEVELOPER);
+        return false;
+    }
+
+    /**
+     * Get the list of available joins for the filter.
+     *
+     * @return array
+     */
+    public function get_join_list(): array {
+        return [
+            datafilter::JOINTYPE_NONE,
+            datafilter::JOINTYPE_ANY,
+            datafilter::JOINTYPE_ALL,
+        ];
+    }
+
+    /**
+     * Given an array of filters, pick the entry that matches the condition key and return it.
+     *
+     * @param array $filters Array of filters, keyed by condition.
+     * @return ?array The filter that matches this condition
+     */
+    public static function get_filter_from_list(array $filters): ?array {
+        return $filters[static::get_condition_key()] ?? null;
+    }
+
+    /**
+     * Build query from filter value
+     *
+     * @param array $filter filter properties
+     * @return array where sql and params
+     */
+    public static function build_query_from_filter(array $filter): array {
+        return ['', []];
+    }
+}

question/classes/local/bank/context_to_string_translator.php

@@ -0,0 +1,98 @@
+<?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_question\local\bank;
+
+/**
+ * Converts contextlevels to strings and back to help with reading/writing contexts to/from import/export files.
+ *
+ * @package   core_question
+ * @copyright 1999 onwards Martin Dougiamas  {@link http://moodle.com}
+ * @author    2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class context_to_string_translator {
+
+    /**
+     * @var array used to translate between contextids and strings for this context.
+     */
+    protected $contexttostringarray = [];
+
+    /**
+     * context_to_string_translator constructor.
+     *
+     * @param \context[] $contexts
+     */
+    public function __construct($contexts) {
+        $this->generate_context_to_string_array($contexts);
+    }
+
+    /**
+     * Context to string.
+     *
+     * @param int $contextid
+     * @return mixed
+     */
+    public function context_to_string($contextid) {
+        return $this->contexttostringarray[$contextid];
+    }
+
+    /**
+     * String to context.
+     *
+     * @param string $contextname
+     * @return false|int|string
+     */
+    public function string_to_context($contextname) {
+        return array_search($contextname, $this->contexttostringarray);
+    }
+
+    /**
+     * Generate context to array.
+     *
+     * @param \context[] $contexts
+     */
+    protected function generate_context_to_string_array($contexts) {
+        if (!$this->contexttostringarray) {
+            $catno = 1;
+            /** @var \context $context */
+            foreach ($contexts as $context) {
+                switch ($context->contextlevel) {
+                    case CONTEXT_MODULE :
+                        $contextstring = 'module';
+                        break;
+                    case CONTEXT_COURSE :
+                        $contextstring = 'course';
+                        break;
+                    case CONTEXT_COURSECAT :
+                        $contextstring = "cat$catno";
+                        $catno++;
+                        break;
+                    case CONTEXT_SYSTEM :
+                        $contextstring = 'system';
+                        break;
+                    default:
+                        throw new \coding_exception('Unexpected context level ' .
+                                \context_helper::get_level_name($context->contextlevel) . ' for context ' .
+                                $context->id . ' in generate_context_to_string_array. ' .
+                                'Questions can never exist in this type of context.');
+                }
+                $this->contexttostringarray[$context->id] = $contextstring;
+            }
+        }
+    }
+
+}

question/classes/local/bank/edit_menu_column.php

@@ -0,0 +1,90 @@
+<?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/>.
+
+/**
+ * A question bank column which gathers together all the actions into a menu.
+ *
+ * @package   core_question
+ * @copyright 2019 The Open University
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\local\bank;
+
+use \core\plugininfo\qbank;
+
+/**
+ * A question bank column which gathers together all the actions into a menu.
+ *
+ * This question bank column, if added to the question bank, will
+ * replace all of the other columns which implement the
+ * {@see menu_action_column_base} interface and replace them with a single
+ * column containing an Edit menu.
+ *
+ * @copyright 2019 The Open University
+ * @author    2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class edit_menu_column extends column_base {
+    public function get_title() {
+        return get_string('actions');
+    }
+
+    public function get_name(): string {
+        return 'editmenu';
+    }
+
+    protected function display_content($question, $rowclasses): void {
+        global $OUTPUT;
+        $actions = $this->qbank->get_question_actions();
+
+        $menu = new \action_menu();
+        $menu->set_menu_trigger(get_string('edit'));
+        $menu->set_boundary('window');
+        foreach ($actions as $action) {
+            $action = $action->get_action_menu_link($question);
+            if ($action) {
+                $menu->add($action);
+            }
+        }
+
+        $qtypeactions = \question_bank::get_qtype($question->qtype, false)
+                ->get_extra_question_bank_actions($question);
+        foreach ($qtypeactions as $action) {
+            $menu->add($action);
+        }
+
+        echo $OUTPUT->render($menu);
+    }
+
+    public function get_required_fields(): array {
+        return ['q.qtype'];
+    }
+
+    /**
+     * Get menuable actions.
+     *
+     * @return menu_action_column_base Menuable actions.
+     */
+    public function get_actions(): array {
+        return $this->actions;
+    }
+
+    public function get_extra_classes(): array {
+        return ['pr-3'];
+    }
+
+}

question/classes/local/bank/filter_condition_manager.php

@@ -0,0 +1,120 @@
+<?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/>.
+
+/**
+ * Functions for managing and manipulating question filter conditions
+ *
+ * @package   core_question
+ * @copyright 2023 onwards Catalyst IT EU {@link https://catalyst-eu.net}
+ * @author    Mark Johnson <mark.johnson@catalyst-eu.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\local\bank;
+
+/**
+ * Static methods for parsing and formatting data related to filter conditions.
+ */
+class filter_condition_manager {
+
+    /**
+     * Extract parameters from args list.
+     *
+     * @param array $args
+     * @return array the param and extra param
+     */
+    public static function extract_parameters_from_fragment_args(array $args): array {
+        $params = [];
+        if (array_key_exists('filter', $args)) {
+            $params['filter'] = json_decode($args['filter'], true);
+        }
+        if (array_key_exists('cmid', $args)) {
+            $params['cmid'] = $args['cmid'];
+        }
+        if (array_key_exists('courseid', $args)) {
+            $params['courseid'] = $args['courseid'];
+        }
+        $params['jointype'] = $args['jointype'] ?? condition::JOINTYPE_DEFAULT;
+        $params['qpage'] = $args['qpage'] ?? 0;
+        $params['qperpage'] = $args['qperpage'] ?? 100;
+        $params['sortdata'] = json_decode($args['sortdata'] ?? '', true);
+        $extraparams = json_decode($args['extraparams'] ?? '', true);
+
+        return [$params, $extraparams];
+    }
+
+    /**
+     * List of condition classes
+     *
+     * @return condition[] condition classes: [condition_key] = class
+     */
+    public static function get_condition_classes(): array {
+        $classes = [];
+        $plugins = \core_component::get_plugin_list_with_class('qbank', 'plugin_feature', 'plugin_feature.php');
+        foreach ($plugins as $componentname => $plugin) {
+            if (\core\plugininfo\qbank::is_plugin_enabled($componentname)) {
+                $pluginentrypointobject = new $plugin();
+                $conditions = $pluginentrypointobject->get_question_filters();
+                foreach ($conditions as $condition) {
+                    $classes[$condition->get_condition_key()] = $condition->get_condition_class();
+                }
+            }
+        }
+        return $classes;
+    }
+
+    /**
+     * Given a JSON-encoded "filter" URL param, create or replace the category filter with the provided category.
+     *
+     * @param string $filterparam The json-encoded filter param from the URL, containing the list of filters.
+     * @param int $newcategoryid The new ID to set for the "category" filter condition's value.
+     * @return string JSON-encoded filter param with the new category.
+     */
+    public static function update_filter_param_to_category(string $filterparam, int $newcategoryid): string {
+        $returnfilters = json_decode($filterparam, true);
+        if (!$returnfilters) {
+            $returnfilters = [
+                'category' => [
+                    'name' => 'category',
+                    'jointype' => \core_question\local\bank\condition::JOINTYPE_DEFAULT,
+                ]
+            ];
+        }
+        $returnfilters['category']['values'] = [$newcategoryid];
+        return json_encode($returnfilters);
+    }
+
+    /**
+     * Unpack filteroptions passed in a request's filter param if required.
+     *
+     * Filteroptions are passed via AJAX as an array of {name:, value:} pairs for compatibility with external functions.
+     *
+     * @param array $filters List of filters, each optionally including an array of filteroptions.
+     * @return array The input array, with filteroptions unpacked from [{name:, value:}, ...] to [name => value, ...].
+     */
+    public static function unpack_filteroptions_param(array $filters): array {
+        foreach ($filters as $name => $filter) {
+            if (!empty($filter['filteroptions']) && isset(reset($filter['filteroptions'])['name'])) {
+                $unpacked = [];
+                foreach ($filter['filteroptions'] as $filteroption) {
+                    $unpacked[$filteroption['name']] = $filteroption['value'];
+                }
+                $filters[$name]['filteroptions'] = $unpacked;
+            }
+        }
+        return $filters;
+    }
+}

question/classes/local/bank/helper.php

@@ -0,0 +1,54 @@
+<?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/>.
+
+/**
+ * Helper class for question bank and its plugins.
+ *
+ * All the functions which has a potential to be used by different features or
+ * plugins, should go here.
+ *
+ * @package    core_question
+ * @copyright  2021 Catalyst IT Australia Pty Ltd
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\local\bank;
+
+/**
+ * Class helper
+ *
+ * @package    core_question
+ * @copyright  2021 Catalyst IT Australia Pty Ltd
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class helper {
+
+    /**
+     * Check the status of a plugin and throw exception if not enabled and called manually.
+     *
+     * Any action plugin having a php script, should call this function for a safer enable/disable implementation.
+     *
+     * @param string $pluginname
+     * @return void
+     */
+    public static function require_plugin_enabled(string $pluginname): void {
+        if (!\core\plugininfo\qbank::is_plugin_enabled($pluginname)) {
+            throw new \moodle_exception('The following plugin is either disabled or missing from disk: ' . $pluginname);
+        }
+    }
+}

question/classes/local/bank/menu_action_column_base.php

@@ -0,0 +1,73 @@
+<?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/>.
+
+/**
+ * Base class to make it easier to implement actions that are menuable_actions.
+ *
+ * @package   core_question
+ * @copyright 2019 Tim Hunt
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\local\bank;
+
+/**
+ * Base class to make it easier to implement actions that are menuable_actions.
+ *
+ * Use this class if your action is simple (defined by just a URL, label and icon).
+ * If your action is not simple enough to fit into the pattern that this
+ * class implements, then you will have to implement the menuable_action
+ * interface yourself.
+ *
+ * @copyright 2019 Tim Hunt
+ * @author    2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @deprecated Since Moodle 4.3 MDL-75125 - Use question_action_base instead.
+ * @todo MDL-78090 This class will be deleted in Moodle 4.7
+ */
+abstract class menu_action_column_base extends action_column_base implements menuable_action {
+
+    /**
+     * Get the information required to display this action either as a menu item or a separate action column.
+     *
+     * If this action cannot apply to this question (e.g. because the user does not have
+     * permission, then return [null, null, null].
+     *
+     * @param \stdClass $question the row from the $question table, augmented with extra information.
+     * @return array with three elements.
+     *      $url - the URL to perform the action.
+     *      $icon - the icon for this action. E.g. 't/delete'.
+     *      $label - text label to display in the UI (either in the menu, or as a tool-tip on the icon)
+     */
+    abstract protected function get_url_icon_and_label(\stdClass $question);
+
+    protected function display_content($question, $rowclasses): void {
+        debugging('The menu_action_column_base class is deprecated. Please use question_action_base instead.', DEBUG_DEVELOPER);
+        [$url, $icon, $label] = $this->get_url_icon_and_label($question);
+        if ($url) {
+            $this->print_icon($icon, $label, $url);
+        }
+    }
+
+    public function get_action_menu_link(\stdClass $question): ?\action_menu_link {
+        debugging('The menu_action_column_base class is deprecated. Please use question_action_base instead.', DEBUG_DEVELOPER);
+        [$url, $icon, $label] = $this->get_url_icon_and_label($question);
+        if (!$url) {
+            return null;
+        }
+        return new \action_menu_link_secondary($url, new \pix_icon($icon, ''), $label);
+    }
+}

question/classes/local/bank/menuable_action.php

@@ -0,0 +1,57 @@
+<?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/>.
+
+/**
+ * Interface to indicate that a question bank column can go in the action menu.
+ *
+ * @package   core_question
+ * @copyright 2019 Tim Hunt
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\local\bank;
+
+/**
+ * Interface to indicate that a question bank column can go in the action menu.
+ *
+ * If a question bank column implements this interface, and if the {@see edit_menu_column}
+ * is present in the question bank view, then the 'column' will be shown as an entry in the
+ * edit menu instead of as a separate column.
+ *
+ * Probably most columns that want to implement this will be subclasses of
+ * {@see action_column_base}, and most such columns should probably implement
+ * this interface.
+ *
+ * If your column is a simple action, you can probably save duplicated code by
+ * using the base class action_column_menuable as an easy way to implement both
+ * action_column_base and this interface.
+ *
+ * @copyright 2019 Tim Hunt
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @deprecated Since Moodle 4.3 MDL-75125 - Use question_action_base instead.
+ * @todo MDL-78090 This interface will be deleted in Moodle 4.7
+ */
+interface menuable_action {
+
+    /**
+     * Return the appropriate action menu link, or null if it does not apply to this question.
+     *
+     * @param \stdClass $question data about the question being displayed in this row.
+     * @return \action_menu_link|null the action, if applicable to this question.
+     * @deprecated Since Moodle 4.3
+     */
+    public function get_action_menu_link(\stdClass $question): ?\action_menu_link;
+}

question/classes/local/bank/navigation_node_base.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/>.
+
+/**
+ * Base class class for navigation node.
+ *
+ * @package    core_question
+ * @copyright  2021 Catalyst IT Australia Pty Ltd
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\local\bank;
+
+/**
+ * Class navigation_node_base is the base class for navigation node.
+ *
+ * @package    core_question
+ * @copyright  2021 Catalyst IT Australia Pty Ltd
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+abstract class navigation_node_base {
+
+    /**
+     * Title for this node.
+     */
+    abstract public function get_navigation_title();
+
+    /**
+     * Key for this node.
+     */
+    abstract public function get_navigation_key();
+
+    /**
+     * URL for this node
+     */
+    abstract public function get_navigation_url();
+
+    /**
+     * Tab capabilities.
+     *
+     * If it has capabilities to be checked, it will return the array of capabilities.
+     *
+     * @return null|array
+     */
+    public function get_navigation_capabilities(): ?array {
+        return null;
+    }
+
+}

question/classes/local/bank/plugin_features_base.php

@@ -0,0 +1,117 @@
+<?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/>.
+
+/**
+ * Base class class for qbank plugins.
+ *
+ * Every qbank plugin must extent this class.
+ *
+ * @package    core_question
+ * @copyright  2021 Catalyst IT Australia Pty Ltd
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\local\bank;
+
+use core\context;
+use qbank_columnsortorder\local\qbank\column_action_move;
+use qbank_columnsortorder\local\qbank\column_action_remove;
+use qbank_columnsortorder\local\qbank\column_action_resize;
+
+/**
+ * Class plugin_features_base is the base class for qbank plugins.
+ *
+ * @package    core_question
+ * @copyright  2021 Catalyst IT Australia Pty Ltd
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class plugin_features_base {
+
+    /**
+     * This method will return the array of objects to be rendered as a part of question bank columns.
+     *
+     * @param view $qbank
+     * @return array
+     */
+    public function get_question_columns(view $qbank): ?array {
+        return [];
+    }
+
+    /**
+     * This method will return the array of objects to be rendered as a part of question bank actions.
+     *
+     * @param view $qbank
+     * @return question_action_base[]
+     */
+    public function get_question_actions(view $qbank): array {
+        return [];
+    }
+
+    /**
+     * This method will return the object for the navigation node.
+     *
+     * @return null|navigation_node_base
+     */
+    public function get_navigation_node(): ?navigation_node_base {
+        return null;
+    }
+
+    /**
+     * This method will return the array objects for the bulk actions ui.
+     *
+     * @return bulk_action_base[]
+     */
+    public function get_bulk_actions() {
+        return [];
+    }
+
+    /**
+     * This method will return a column manager object, if this plugin provides one.
+     *
+     * @return ?column_manager_base
+     */
+    public function get_column_manager(): ?column_manager_base {
+        return null;
+    }
+
+    /**
+     * This method will return an array of renderable objects, for adding additional controls to the question bank screen.
+     *
+     * The array returned can include a numeric index for each object, to indicate the position in which it should be displayed
+     * relative to other controls. If two plugins return controls with the same position, they will be displayed after one another,
+     * based on the alphabetical order of the plugin component names.
+     *
+     * @param view $qbank The question bank view.
+     * @param context $context The current context, for permission checks.
+     * @param int $categoryid The current question category ID.
+     * @return \renderable[]
+     */
+    public function get_question_bank_controls(view $qbank, context $context, int $categoryid): array {
+        return [];
+    }
+
+    /**
+     * Return search conditions for the plugin.
+     *
+     * @param view|null $qbank
+     * @return condition[]
+     */
+    public function get_question_filters(view $qbank = null): array {
+        return [];
+    }
+}

question/classes/local/bank/question_action_base.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/>.
+
+/**
+ * Base class to make it easier to implement actions that are menuable_actions.
+ *
+ * @package   core_question
+ * @copyright 2019 Tim Hunt
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\local\bank;
+
+/**
+ * Base class to make it easier to implement actions that are menuable_actions.
+ *
+ * Use this class if your action is simple (defined by just a URL, label and icon).
+ * If your action is not simple enough to fit into the pattern that this
+ * class implements, then you will have to implement the menuable_action
+ * interface yourself.
+ *
+ * @copyright 2019 Tim Hunt
+ * @author    2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+abstract class question_action_base extends view_component {
+
+    /**
+     * Get the information required to display this action either as a menu item or a separate action column.
+     *
+     * For most actions, it should be sufficient to override just this method. {@see get_action_menu_link()} is the public interface
+     * and handles building a renderable menu link object from this data.
+     *
+     * If this action cannot apply to this question (e.g. because the user does not have
+     * permission, then return [null, null, null].
+     *
+     * @param \stdClass $question the row from the $question table, augmented with extra information.
+     * @return array with three elements.
+     *      $url - the URL to perform the action.
+     *      $icon - the icon for this action. E.g. 't/delete'.
+     *      $label - text label to display in the UI (either in the menu, or as a tool-tip on the icon)
+     */
+    protected function get_url_icon_and_label(\stdClass $question): array {
+        return [null, null, null];
+    }
+
+    /**
+     * Return the action menu link for this action on the supplied question.
+     *
+     * For most actions, you will just need to override {@see get_url_icon_and_label()}. You only need to override
+     * this method if you need to pass additional attributes to {@see action_menu_link_secondary}, or use a different class to
+     * render the link.
+     *
+     * @param \stdClass $question
+     * @return \action_menu_link|null
+     */
+    public function get_action_menu_link(\stdClass $question): ?\action_menu_link {
+        [$url, $icon, $label] = $this->get_url_icon_and_label($question);
+        if (!$url) {
+            return null;
+        }
+        return new \action_menu_link_secondary($url, new \pix_icon($icon, ''), $label);
+    }
+}

question/classes/local/bank/question_edit_contexts.php

@@ -0,0 +1,222 @@
+<?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_question\local\bank;
+
+/**
+ * Tracks all the contexts related to the one we are currently editing questions and provides helper methods to check permissions.
+ *
+ * @package   core_question
+ * @copyright 2007 Jamie Pratt me@jamiep.org
+ * @author    2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class question_edit_contexts {
+
+    /**
+     * @var \string[][] array of the capabilities.
+     */
+    public static $caps = [
+            'editq' => [
+                    'moodle/question:add',
+                    'moodle/question:editmine',
+                    'moodle/question:editall',
+                    'moodle/question:viewmine',
+                    'moodle/question:viewall',
+                    'moodle/question:usemine',
+                    'moodle/question:useall',
+                    'moodle/question:movemine',
+                    'moodle/question:moveall'],
+            'questions' => [
+                    'moodle/question:add',
+                    'moodle/question:editmine',
+                    'moodle/question:editall',
+                    'moodle/question:viewmine',
+                    'moodle/question:viewall',
+                    'moodle/question:movemine',
+                    'moodle/question:moveall'],
+            'categories' => [
+                    'moodle/question:managecategory'],
+            'import' => [
+                    'moodle/question:add'],
+            'export' => [
+                    'moodle/question:viewall',
+                    'moodle/question:viewmine']];
+
+    /**
+     * @var array of contexts.
+     */
+    protected $allcontexts;
+
+    /**
+     * Constructor
+     * @param \context $thiscontext the current context.
+     */
+    public function __construct(\context $thiscontext) {
+        $this->allcontexts = array_values($thiscontext->get_parent_contexts(true));
+    }
+
+    /**
+     * Get all the contexts.
+     *
+     * @return \context[] all parent contexts
+     */
+    public function all() {
+        return $this->allcontexts;
+    }
+
+    /**
+     * Get the lowest context.
+     *
+     * @return \context lowest context which must be either the module or course context
+     */
+    public function lowest() {
+        return $this->allcontexts[0];
+    }
+
+    /**
+     * Get the contexts having cap.
+     *
+     * @param string $cap capability
+     * @return \context[] parent contexts having capability, zero based index
+     */
+    public function having_cap($cap) {
+        $contextswithcap = [];
+        foreach ($this->allcontexts as $context) {
+            if (has_capability($cap, $context)) {
+                $contextswithcap[] = $context;
+            }
+        }
+        return $contextswithcap;
+    }
+
+    /**
+     * Get the contexts having at least one cap.
+     *
+     * @param array $caps capabilities
+     * @return \context[] parent contexts having at least one of $caps, zero based index
+     */
+    public function having_one_cap($caps) {
+        $contextswithacap = [];
+        foreach ($this->allcontexts as $context) {
+            foreach ($caps as $cap) {
+                if (has_capability($cap, $context)) {
+                    $contextswithacap[] = $context;
+                    break; // Done with caps loop.
+                }
+            }
+        }
+        return $contextswithacap;
+    }
+
+    /**
+     * Context having at least one cap.
+     *
+     * @param string $tabname edit tab name
+     * @return \context[] parent contexts having at least one of $caps, zero based index
+     */
+    public function having_one_edit_tab_cap($tabname) {
+        return $this->having_one_cap(self::$caps[$tabname]);
+    }
+
+    /**
+     * Contexts for adding question and also using it.
+     *
+     * @return \context[] those contexts where a user can add a question and then use it.
+     */
+    public function having_add_and_use() {
+        $contextswithcap = [];
+        foreach ($this->allcontexts as $context) {
+            if (!has_capability('moodle/question:add', $context)) {
+                continue;
+            }
+            if (!has_any_capability(['moodle/question:useall', 'moodle/question:usemine'], $context)) {
+                continue;
+            }
+            $contextswithcap[] = $context;
+        }
+        return $contextswithcap;
+    }
+
+    /**
+     * Has at least one parent context got the cap $cap?
+     *
+     * @param string $cap capability
+     * @return boolean
+     */
+    public function have_cap($cap) {
+        return (count($this->having_cap($cap)));
+    }
+
+    /**
+     * Has at least one parent context got one of the caps $caps?
+     *
+     * @param array $caps capability
+     * @return boolean
+     */
+    public function have_one_cap($caps) {
+        foreach ($caps as $cap) {
+            if ($this->have_cap($cap)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Has at least one parent context got one of the caps for actions on $tabname
+     *
+     * @param string $tabname edit tab name
+     * @return boolean
+     */
+    public function have_one_edit_tab_cap($tabname) {
+        return $this->have_one_cap(self::$caps[$tabname]);
+    }
+
+    /**
+     * Throw error if at least one parent context hasn't got the cap $cap
+     *
+     * @param string $cap capability
+     */
+    public function require_cap($cap) {
+        if (!$this->have_cap($cap)) {
+            throw new \moodle_exception('nopermissions', '', '', $cap);
+        }
+    }
+
+    /**
+     * Throw error if at least one parent context hasn't got one of the caps $caps
+     *
+     * @param array $caps capabilities
+     */
+    public function require_one_cap($caps) {
+        if (!$this->have_one_cap($caps)) {
+            $capsstring = join(', ', $caps);
+            throw new \moodle_exception('nopermissions', '', '', $capsstring);
+        }
+    }
+
+    /**
+     * Throw error if at least one parent context hasn't got one of the caps $caps
+     *
+     * @param string $tabname edit tab name
+     */
+    public function require_one_edit_tab_cap($tabname) {
+        if (!$this->have_one_edit_tab_cap($tabname)) {
+            throw new \moodle_exception('nopermissions', '', '', 'access question edit tab '.$tabname);
+        }
+    }
+}

question/classes/local/bank/question_version_status.php

@@ -0,0 +1,43 @@
+<?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_question\local\bank;
+
+/**
+ * Class question_version_status contains the statuses for a question.
+ *
+ * @package    core_question
+ * @copyright  2021 Catalyst IT Australia Pty Ltd
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class question_version_status {
+
+    /**
+     * Const if the question is ready to use.
+     */
+    const QUESTION_STATUS_READY = 'ready';
+
+    /**
+     * Const if the question is hidden.
+     */
+    const QUESTION_STATUS_HIDDEN = 'hidden';
+
+    /**
+     * const if the question is in draft.
+     */
+    const QUESTION_STATUS_DRAFT = 'draft';
+}

question/classes/local/bank/random_question_loader.php

@@ -0,0 +1,609 @@
+<?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/>.
+
+/**
+ * A class for efficiently finds questions at random from the question bank.
+ *
+ * @package   core_question
+ * @copyright 2015 The Open University
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\local\bank;
+
+/**
+ * This class efficiently finds questions at random from the question bank.
+ *
+ * You can ask for questions at random one at a time. Each time you ask, you
+ * pass a category id, and whether to pick from that category and all subcategories
+ * or just that category.
+ *
+ * The number of teams each question has been used is tracked, and we will always
+ * return a question from among those elegible that has been used the fewest times.
+ * So, if there are questions that have not been used yet in the category asked for,
+ * one of those will be returned. However, within one instantiation of this class,
+ * we will never return a given question more than once, and we will never return
+ * questions passed into the constructor as $usedquestions.
+ *
+ * @copyright 2015 The Open University
+ * @author    2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class random_question_loader {
+    /** @var \qubaid_condition which usages to consider previous attempts from. */
+    protected $qubaids;
+
+    /** @var array qtypes that cannot be used by random questions. */
+    protected $excludedqtypes;
+
+    /** @var array categoryid & include subcategories => num previous uses => questionid => 1. */
+    protected $availablequestionscache = [];
+
+    /**
+     * @var array questionid => num recent uses. Questions that have been used,
+     * but that is not yet recorded in the DB.
+     */
+    protected $recentlyusedquestions;
+
+    /**
+     * Constructor.
+     *
+     * @param \qubaid_condition $qubaids the usages to consider when counting previous uses of each question.
+     * @param array $usedquestions questionid => number of times used count. If we should allow for
+     *      further existing uses of a question in addition to the ones in $qubaids.
+     */
+    public function __construct(\qubaid_condition $qubaids, array $usedquestions = []) {
+        $this->qubaids = $qubaids;
+        $this->recentlyusedquestions = $usedquestions;
+
+        foreach (\question_bank::get_all_qtypes() as $qtype) {
+            if (!$qtype->is_usable_by_random()) {
+                $this->excludedqtypes[] = $qtype->name();
+            }
+        }
+    }
+
+    /**
+     * Pick a random question based on filter conditions
+     *
+     * @param array $filters filter array
+     * @return int|null
+     */
+    public function get_next_filtered_question_id(array $filters): ?int {
+        $this->ensure_filtered_questions_loaded($filters);
+
+        $key = $this->get_filtered_questions_key($filters);
+        if (empty($this->availablequestionscache[$key])) {
+            return null;
+        }
+
+        reset($this->availablequestionscache[$key]);
+        $lowestcount = key($this->availablequestionscache[$key]);
+        reset($this->availablequestionscache[$key][$lowestcount]);
+        $questionid = key($this->availablequestionscache[$key][$lowestcount]);
+        $this->use_question($questionid);
+        return $questionid;
+    }
+
+
+    /**
+     * Pick a question at random from the given category, from among those with the fewest uses.
+     * If an array of tag ids are specified, then only the questions that are tagged with ALL those tags will be selected.
+     *
+     * It is up the the caller to verify that the cateogry exists. An unknown category
+     * behaves like an empty one.
+     *
+     * @param int $categoryid the id of a category in the question bank.
+     * @param bool $includesubcategories wether to pick a question from exactly
+     *      that category, or that category and subcategories.
+     * @param array $tagids An array of tag ids. A question has to be tagged with all the provided tagids (if any)
+     *      in order to be eligible for being picked.
+     * @return int|null the id of the question picked, or null if there aren't any.
+     * @deprecated since Moodle 4.3
+     * @todo Final deprecation on Moodle 4.7 MDL-78091
+     */
+    public function get_next_question_id($categoryid, $includesubcategories, $tagids = []): ?int {
+        debugging(
+            'Function get_next_question_id() is deprecated, please use get_next_filtered_question_id() instead.',
+            DEBUG_DEVELOPER
+        );
+
+        $this->ensure_questions_for_category_loaded($categoryid, $includesubcategories, $tagids);
+
+        $categorykey = $this->get_category_key($categoryid, $includesubcategories, $tagids);
+        if (empty($this->availablequestionscache[$categorykey])) {
+            return null;
+        }
+
+        reset($this->availablequestionscache[$categorykey]);
+        $lowestcount = key($this->availablequestionscache[$categorykey]);
+        reset($this->availablequestionscache[$categorykey][$lowestcount]);
+        $questionid = key($this->availablequestionscache[$categorykey][$lowestcount]);
+        $this->use_question($questionid);
+        return $questionid;
+    }
+
+    /**
+     * Key for filtered questions.
+     * This function replace get_category_key
+     *
+     * @param array $filters filter array
+     * @return String
+     */
+    protected function get_filtered_questions_key(array $filters): String {
+        return sha1(json_encode($filters));
+    }
+
+    /**
+     * Get the key into {@see $availablequestionscache} for this combination of options.
+     *
+     * @param int $categoryid the id of a category in the question bank.
+     * @param bool $includesubcategories wether to pick a question from exactly
+     *      that category, or that category and subcategories.
+     * @param array $tagids an array of tag ids.
+     * @return string the cache key.
+     *
+     * @deprecated since Moodle 4.3
+     * @todo Final deprecation on Moodle 4.7 MDL-78091
+     */
+    protected function get_category_key($categoryid, $includesubcategories, $tagids = []): string {
+        debugging(
+            'Function get_category_key() is deprecated, please get_fitlered_questions_key instead.',
+            DEBUG_DEVELOPER
+        );
+        if ($includesubcategories) {
+            $key = $categoryid . '|1';
+        } else {
+            $key = $categoryid . '|0';
+        }
+
+        if (!empty($tagids)) {
+            $key .= '|' . implode('|', $tagids);
+        }
+
+        return $key;
+    }
+
+    /**
+     * Populate {@see $availablequestionscache} according to filter conditions.
+     *
+     * @param array $filters filter array
+     * @return void
+     */
+    protected function ensure_filtered_questions_loaded(array $filters) {
+        global $DB;
+
+        // Check if this is already done.
+        $key = $this->get_filtered_questions_key($filters);
+        if (isset($this->availablequestionscache[$key])) {
+            // Data is already in the cache, nothing to do.
+            return;
+        }
+
+        // Build filter conditions.
+        $params = [];
+        $filterconditions = [];
+        foreach (filter_condition_manager::get_condition_classes() as $conditionclass) {
+            $filter = $conditionclass::get_filter_from_list($filters);
+            if (is_null($filter)) {
+                continue;
+            }
+
+            [$filterwhere, $filterparams] = $conditionclass::build_query_from_filter($filter);
+            if (!empty($filterwhere)) {
+                $filterconditions[] = '(' . $filterwhere . ')';
+            }
+            if (!empty($filterparams)) {
+                $params = array_merge($params, $filterparams);
+            }
+        }
+        $filtercondition = $filterconditions ? 'AND ' . implode(' AND ', $filterconditions) : '';
+
+        // Prepare qtype check.
+        [$qtypecondition, $qtypeparams] = $DB->get_in_or_equal($this->excludedqtypes,
+            SQL_PARAMS_NAMED, 'excludedqtype', false);
+        if ($qtypecondition) {
+            $qtypecondition = 'AND q.qtype ' . $qtypecondition;
+        }
+
+        $questionidsandcounts = $DB->get_records_sql_menu("
+                SELECT q.id,
+                       (
+                           SELECT COUNT(1)
+                             FROM {$this->qubaids->from_question_attempts('qa')}
+                            WHERE qa.questionid = q.id AND {$this->qubaids->where()}
+                       ) AS previous_attempts
+
+                  FROM {question} q
+                  JOIN {question_versions} qv ON qv.questionid = q.id
+                  JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid
+
+                 WHERE q.parent = :noparent
+                   $qtypecondition
+                   $filtercondition
+                   AND qv.version = (
+                           SELECT MAX(version)
+                             FROM {question_versions}
+                            WHERE questionbankentryid = qbe.id
+                              AND status = :ready
+                       )
+
+              ORDER BY previous_attempts
+            ", array_merge(
+                $params,
+                $this->qubaids->from_where_params(),
+                ['noparent' => 0, 'ready' => question_version_status::QUESTION_STATUS_READY],
+                $qtypeparams,
+            ));
+
+        if (!$questionidsandcounts) {
+            // No questions in this category.
+            $this->availablequestionscache[$key] = [];
+            return;
+        }
+
+        // Put all the questions with each value of $prevusecount in separate arrays.
+        $idsbyusecount = [];
+        foreach ($questionidsandcounts as $questionid => $prevusecount) {
+            if (isset($this->recentlyusedquestions[$questionid])) {
+                // Recently used questions are never returned.
+                continue;
+            }
+            $idsbyusecount[$prevusecount][] = $questionid;
+        }
+
+        // Now put that data into our cache. For each count, we need to shuffle
+        // questionids, and make those the keys of an array.
+        $this->availablequestionscache[$key] = [];
+        foreach ($idsbyusecount as $prevusecount => $questionids) {
+            shuffle($questionids);
+            $this->availablequestionscache[$key][$prevusecount] = array_combine(
+                $questionids, array_fill(0, count($questionids), 1));
+        }
+        ksort($this->availablequestionscache[$key]);
+    }
+
+    /**
+     * Populate {@see $availablequestionscache} for this combination of options.
+     *
+     * @param int $categoryid The id of a category in the question bank.
+     * @param bool $includesubcategories Whether to pick a question from exactly
+     *      that category, or that category and subcategories.
+     * @param array $tagids An array of tag ids. If an array is provided, then
+     *      only the questions that are tagged with ALL the provided tagids will be loaded.
+     * @deprecated since Moodle 4.3
+     * @todo Final deprecation on Moodle 4.7 MDL-78091
+     */
+    protected function ensure_questions_for_category_loaded($categoryid, $includesubcategories, $tagids = []): void {
+        debugging(
+            'Function ensure_questions_for_category_loaded() is deprecated, please use the function ' .
+                'ensure_filtered_questions_loaded.',
+            DEBUG_DEVELOPER
+        );
+
+        global $DB;
+
+        $categorykey = $this->get_category_key($categoryid, $includesubcategories, $tagids);
+
+        if (isset($this->availablequestionscache[$categorykey])) {
+            // Data is already in the cache, nothing to do.
+            return;
+        }
+
+        // Load the available questions from the question bank.
+        if ($includesubcategories) {
+            $categoryids = question_categorylist($categoryid);
+        } else {
+            $categoryids = [$categoryid];
+        }
+
+        list($extraconditions, $extraparams) = $DB->get_in_or_equal($this->excludedqtypes,
+                SQL_PARAMS_NAMED, 'excludedqtype', false);
+
+        $questionidsandcounts = \question_bank::get_finder()->get_questions_from_categories_and_tags_with_usage_counts(
+                $categoryids, $this->qubaids, 'q.qtype ' . $extraconditions, $extraparams, $tagids);
+        if (!$questionidsandcounts) {
+            // No questions in this category.
+            $this->availablequestionscache[$categorykey] = [];
+            return;
+        }
+
+        // Put all the questions with each value of $prevusecount in separate arrays.
+        $idsbyusecount = [];
+        foreach ($questionidsandcounts as $questionid => $prevusecount) {
+            if (isset($this->recentlyusedquestions[$questionid])) {
+                // Recently used questions are never returned.
+                continue;
+            }
+            $idsbyusecount[$prevusecount][] = $questionid;
+        }
+
+        // Now put that data into our cache. For each count, we need to shuffle
+        // questionids, and make those the keys of an array.
+        $this->availablequestionscache[$categorykey] = [];
+        foreach ($idsbyusecount as $prevusecount => $questionids) {
+            shuffle($questionids);
+            $this->availablequestionscache[$categorykey][$prevusecount] = array_combine(
+                    $questionids, array_fill(0, count($questionids), 1));
+        }
+        ksort($this->availablequestionscache[$categorykey]);
+    }
+
+    /**
+     * Update the internal data structures to indicate that a given question has
+     * been used one more time.
+     *
+     * @param int $questionid the question that is being used.
+     */
+    protected function use_question($questionid): void {
+        if (isset($this->recentlyusedquestions[$questionid])) {
+            $this->recentlyusedquestions[$questionid] += 1;
+        } else {
+            $this->recentlyusedquestions[$questionid] = 1;
+        }
+
+        foreach ($this->availablequestionscache as $categorykey => $questionsforcategory) {
+            foreach ($questionsforcategory as $numuses => $questionids) {
+                if (!isset($questionids[$questionid])) {
+                    continue;
+                }
+                unset($this->availablequestionscache[$categorykey][$numuses][$questionid]);
+                if (empty($this->availablequestionscache[$categorykey][$numuses])) {
+                    unset($this->availablequestionscache[$categorykey][$numuses]);
+                }
+            }
+        }
+    }
+
+    /**
+     * Get filtered questions.
+     *
+     * @param array $filters filter array
+     * @return array list of filtered questions
+     */
+    protected function get_filtered_question_ids(array $filters): array {
+        $this->ensure_filtered_questions_loaded($filters);
+        $key = $this->get_filtered_questions_key($filters);
+
+        $cachedvalues = $this->availablequestionscache[$key];
+        $questionids = [];
+
+        foreach ($cachedvalues as $usecount => $ids) {
+            $questionids = array_merge($questionids, array_keys($ids));
+        }
+
+        return $questionids;
+    }
+
+    /**
+     * Get the list of available question ids for the given criteria.
+     *
+     * @param int $categoryid The id of a category in the question bank.
+     * @param bool $includesubcategories Whether to pick a question from exactly
+     *      that category, or that category and subcategories.
+     * @param array $tagids An array of tag ids. If an array is provided, then
+     *      only the questions that are tagged with ALL the provided tagids will be loaded.
+     * @return int[] The list of question ids
+     * @deprecated since Moodle 4.3
+     * @todo Final deprecation on Moodle 4.7 MDL-78091
+     */
+    protected function get_question_ids($categoryid, $includesubcategories, $tagids = []): array {
+        debugging(
+            'Function get_question_ids() is deprecated, please use get_filtered_question_ids() instead.',
+            DEBUG_DEVELOPER
+        );
+
+        $this->ensure_questions_for_category_loaded($categoryid, $includesubcategories, $tagids);
+        $categorykey = $this->get_category_key($categoryid, $includesubcategories, $tagids);
+        $cachedvalues = $this->availablequestionscache[$categorykey];
+        $questionids = [];
+
+        foreach ($cachedvalues as $usecount => $ids) {
+            $questionids = array_merge($questionids, array_keys($ids));
+        }
+
+        return $questionids;
+    }
+
+    /**
+     * Check whether a given question is available in a given category. If so, mark it used.
+     * If an optional list of tag ids are provided, then the question must be tagged with
+     * ALL of the provided tags to be considered as available.
+     *
+     * @param array $filters filter array
+     * @param int $questionid the question that is being used.
+     * @return bool whether the question is available in the requested category.
+     */
+    public function is_filtered_question_available(array $filters, int $questionid): bool {
+        $this->ensure_filtered_questions_loaded($filters);
+        $categorykey = $this->get_filtered_questions_key($filters);
+
+        foreach ($this->availablequestionscache[$categorykey] as $questionids) {
+            if (isset($questionids[$questionid])) {
+                $this->use_question($questionid);
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Check whether a given question is available in a given category. If so, mark it used.
+     * If an optional list of tag ids are provided, then the question must be tagged with
+     * ALL of the provided tags to be considered as available.
+     *
+     * @param int $categoryid the id of a category in the question bank.
+     * @param bool $includesubcategories wether to pick a question from exactly
+     *      that category, or that category and subcategories.
+     * @param int $questionid the question that is being used.
+     * @param array $tagids An array of tag ids. Only the questions that are tagged with all the provided tagids can be available.
+     * @return bool whether the question is available in the requested category.
+     * @deprecated since Moodle 4.3
+     * @todo Final deprecation on Moodle 4.7 MDL-78091
+     */
+    public function is_question_available($categoryid, $includesubcategories, $questionid, $tagids = []): bool {
+        debugging(
+            'Function is_question_available() is deprecated, please use is_filtered_question_available() instead.',
+            DEBUG_DEVELOPER
+        );
+        $this->ensure_questions_for_category_loaded($categoryid, $includesubcategories, $tagids);
+        $categorykey = $this->get_category_key($categoryid, $includesubcategories, $tagids);
+
+        foreach ($this->availablequestionscache[$categorykey] as $questionids) {
+            if (isset($questionids[$questionid])) {
+                $this->use_question($questionid);
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Get the list of available questions for the given criteria.
+     *
+     * @param array $filters filter array
+     * @param int $limit Maximum number of results to return.
+     * @param int $offset Number of items to skip from the begging of the result set.
+     * @param string[] $fields The fields to return for each question.
+     * @return \stdClass[] The list of question records
+     */
+    public function get_filtered_questions($filters, $limit = 100, $offset = 0, $fields = []) {
+        global $DB;
+
+        $questionids = $this->get_filtered_question_ids($filters);
+
+        if (empty($questionids)) {
+            return [];
+        }
+
+        if (empty($fields)) {
+            // Return all fields.
+            $fieldsstring = '*';
+        } else {
+            $fieldsstring = implode(',', $fields);
+        }
+
+        // Create the query to get the questions (validate that at least we have a question id. If not, do not execute the sql).
+        $hasquestions = false;
+        if (!empty($questionids)) {
+            $hasquestions = true;
+        }
+        if ($hasquestions) {
+            [$condition, $param] = $DB->get_in_or_equal($questionids, SQL_PARAMS_NAMED, 'questionid');
+            $condition = 'WHERE q.id ' . $condition;
+            $sql = "SELECT {$fieldsstring}
+                      FROM (SELECT q.*, qbe.questioncategoryid as category
+                      FROM {question} q
+                      JOIN {question_versions} qv ON qv.questionid = q.id
+                      JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid
+                      {$condition}) q
+                  ORDER BY q.id";
+
+            return $DB->get_records_sql($sql, $param, $offset, $limit);
+        } else {
+            return [];
+        }
+    }
+
+    /**
+     * Get the list of available questions for the given criteria.
+     *
+     * @param int $categoryid The id of a category in the question bank.
+     * @param bool $includesubcategories Whether to pick a question from exactly
+     *      that category, or that category and subcategories.
+     * @param array $tagids An array of tag ids. If an array is provided, then
+     *      only the questions that are tagged with ALL the provided tagids will be loaded.
+     * @param int $limit Maximum number of results to return.
+     * @param int $offset Number of items to skip from the begging of the result set.
+     * @param string[] $fields The fields to return for each question.
+     * @return \stdClass[] The list of question records
+     * @deprecated since Moodle 4.3
+     * @todo Final deprecation on Moodle 4.7 MDL-78091
+     */
+    public function get_questions($categoryid, $includesubcategories, $tagids = [], $limit = 100, $offset = 0, $fields = []) {
+        debugging(
+            'Function get_questions() is deprecated, please use get_filtered_questions() instead.',
+            DEBUG_DEVELOPER
+        );
+        global $DB;
+
+        $questionids = $this->get_question_ids($categoryid, $includesubcategories, $tagids);
+        if (empty($questionids)) {
+            return [];
+        }
+
+        if (empty($fields)) {
+            // Return all fields.
+            $fieldsstring = '*';
+        } else {
+            $fieldsstring = implode(',', $fields);
+        }
+
+        // Create the query to get the questions (validate that at least we have a question id. If not, do not execute the sql).
+        $hasquestions = false;
+        if (!empty($questionids)) {
+            $hasquestions = true;
+        }
+        if ($hasquestions) {
+            list($condition, $param) = $DB->get_in_or_equal($questionids, SQL_PARAMS_NAMED, 'questionid');
+            $condition = 'WHERE q.id ' . $condition;
+            $sql = "SELECT {$fieldsstring}
+                      FROM (SELECT q.*, qbe.questioncategoryid as category
+                      FROM {question} q
+                      JOIN {question_versions} qv ON qv.questionid = q.id
+                      JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid
+                      {$condition}) q ORDER BY q.id";
+
+            return $DB->get_records_sql($sql, $param, $offset, $limit);
+        } else {
+            return [];
+        }
+    }
+
+    /**
+     * Count number of filtered questions
+     *
+     * @param array $filters filter array
+     * @return int number of question
+     */
+    public function count_filtered_questions(array $filters): int {
+        $questionids = $this->get_filtered_question_ids($filters);
+        return count($questionids);
+    }
+
+    /**
+     * Count the number of available questions for the given criteria.
+     *
+     * @param int $categoryid The id of a category in the question bank.
+     * @param bool $includesubcategories Whether to pick a question from exactly
+     *      that category, or that category and subcategories.
+     * @param array $tagids An array of tag ids. If an array is provided, then
+     *      only the questions that are tagged with ALL the provided tagids will be loaded.
+     * @return int The number of questions matching the criteria.
+     * @deprecated since Moodle 4.3
+     * @todo Final deprecation on Moodle 4.7 MDL-78091
+     */
+    public function count_questions($categoryid, $includesubcategories, $tagids = []): int {
+        debugging(
+            'Function count_questions() is deprecated, please use count_filtered_questions() instead.',
+            DEBUG_DEVELOPER
+        );
+        $questionids = $this->get_question_ids($categoryid, $includesubcategories, $tagids);
+        return count($questionids);
+    }
+}

question/classes/local/bank/row_base.php

@@ -0,0 +1,70 @@
+<?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/>.
+
+/**
+ * Base class for 'columns' that are actually displayed as a row following the main question row.
+ *
+ * @package   core_question
+ * @copyright 2009 Tim Hunt
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\local\bank;
+
+/**
+ * Base class for 'columns' that are actually displayed as a row following the main question row.
+ *
+ * @copyright 2009 Tim Hunt
+ * @author    2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+abstract class row_base extends column_base {
+
+    /**
+     * Check if the column is an extra row of not.
+     */
+    public function is_extra_row(): bool {
+        return true;
+    }
+
+    /**
+     * Output the opening column tag.  If it is set as heading, it will use <th> tag instead of <td>
+     *
+     * @param \stdClass $question
+     * @param string $rowclasses
+     */
+    protected function display_start($question, $rowclasses): void {
+        if ($rowclasses) {
+            echo \html_writer::start_tag('tr', ['class' => $rowclasses]);
+        } else {
+            echo \html_writer::start_tag('tr');
+        }
+        echo \html_writer::start_tag('td',
+                ['colspan' => $this->qbank->get_column_count(), 'class' => $this->get_name()]);
+    }
+
+    /**
+     * Output the closing column tag
+     *
+     * @param object $question
+     * @param string $rowclasses
+     */
+    protected function display_end($question, $rowclasses): void {
+        echo \html_writer::end_tag('td');
+        echo \html_writer::end_tag('tr');
+    }
+
+}

question/classes/local/bank/view_component.php

@@ -0,0 +1,102 @@
+<?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_question\local\bank;
+
+/**
+ * Abstract class to define functionality shared by all pluggable components used in the question bank view.
+ *
+ * @package   core_question
+ * @copyright 2023 onwards Catalyst IT EU {@link https://catalyst-eu.net}
+ * @author    Mark Johnson <mark.johnson@catalyst-eu.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+abstract class view_component {
+    /** @var int value we return from get_menu_position here. Subclasses should override this. */
+    const MENU_POSITION_NOT_SET = 6666;
+
+    /** @var view Question bank view. */
+    protected $qbank;
+
+    /**
+     * Constructor.
+     * @param view $qbank the question bank view we are helping to render.
+     */
+    public function __construct(view $qbank) {
+        $this->qbank = $qbank;
+        $this->init();
+    }
+
+    /**
+     * A chance for subclasses to initialise themselves, for example to load lang strings,
+     * without having to override the constructor.
+     */
+    protected function init(): void {
+    }
+
+    /**
+     * Return an integer to indicate the desired position in the menu for this link, smaller at the top.
+     *
+     * The standard menu items in Moodle core return these numbers:
+     * 100 preview_action
+     * 200 edit_action
+     * 250 copy_action
+     * 300 tags_action
+     * 400 delete_action
+     * 500 history_action
+     * 600 export_xml_action
+     * (So, if you want your action at a particular place in the order, there should be space.)
+     *
+     * If two actions get the same order number, then the tie-break on the sort
+     * is plugin name, then the order returned by get_question_actions for that plugin.
+     *
+     * @return int desired position. Smallest at the top.
+     */
+    public function get_menu_position(): int {
+        // We return a big number by default, which is after all the standard core links,
+        // so they go first. This should be overridden by all plugins, and not overriding will
+        // generate a debugging warning from {@see \core_question\local\bank\view::init_question_actions()}.
+        return self::MENU_POSITION_NOT_SET;
+    }
+
+    /**
+     * Return an array 'table_alias' => 'JOIN clause' to bring in any data that
+     * this feature requires.
+     *
+     * The return values for all the features will be checked. It is OK if two
+     * features join in the same table with the same alias and identical JOIN clauses.
+     * If two features try to use the same alias with different joins, you get an error.
+     * Tables included by default are question (alias q) and those defined in {@see view::get_required_joins()}
+     *
+     * It is importnat that your join simply adds additional data (or NULLs) to the
+     * existing rows of the query. It must not cause additional rows.
+     *
+     * @return string[] 'table_alias' => 'JOIN clause'
+     */
+    public function get_extra_joins(): array {
+        return [];
+    }
+
+    /**
+     * Use table alias 'q' for the question table, or one of the
+     * ones from get_extra_joins. Every field requested must specify a table prefix.
+     *
+     * @return string[] fields required.
+     */
+    public function get_required_fields(): array {
+        return [];
+    }
+}

question/classes/local/statistics/statistics_bulk_loader.php

@@ -0,0 +1,180 @@
+<?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_question\local\statistics;
+
+use core_question\local\bank\column_base;
+use core_question\statistics\questions\all_calculated_for_qubaid_condition;
+use core_component;
+
+/**
+ * Helper to efficiently load all the statistics for a set of questions.
+ *
+ * If you are implementing a question bank column, do not use this method directly.
+ * Instead, override the {@see column_base::get_required_statistics_fields()} method
+ * in your column class, and the question bank view will take care of it for you.
+ *
+ * @package   core_question
+ * @copyright 2023 The Open University
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class statistics_bulk_loader {
+
+    /**
+     * Load and aggregate the requested statistics for all the places where the given questions are used.
+     *
+     * The returned array will contain a values for each questionid and field, which will be null if the value is not available.
+     *
+     * @param int[] $questionids array of question ids.
+     * @param string[] $requiredstatistics array of the fields required, e.g. ['facility', 'discriminationindex'].
+     * @return float[][] if a value is not available, it will be set to null.
+     */
+    public static function load_aggregate_statistics(array $questionids, array $requiredstatistics): array {
+        // Prevent unnecessary statistics calculations.
+        if (empty($requiredstatistics)) {
+            $aggregates = [];
+            foreach ($questionids as $questionid) {
+                $aggregates[$questionid] = [];
+            }
+            return $aggregates;
+        }
+
+        $places = self::get_all_places_where_questions_were_attempted($questionids);
+
+        // Set up blank two-dimensional arrays to store the running totals. Indexed by questionid and field name.
+        $zerovaluesforonequestion = array_combine($requiredstatistics, array_fill(0, count($requiredstatistics), 0));
+        $counts = array_combine($questionids, array_fill(0, count($questionids), $zerovaluesforonequestion));
+        $sums = array_combine($questionids, array_fill(0, count($questionids), $zerovaluesforonequestion));
+
+        // Load the data for each place, and add to the running totals.
+        foreach ($places as $place) {
+            $statistics = self::load_statistics_for_place($place->component,
+                    \context::instance_by_id($place->contextid));
+            if ($statistics === null) {
+                continue;
+            }
+
+            foreach ($questionids as $questionid) {
+                foreach ($requiredstatistics as $item) {
+                    $value = self::extract_item_value($statistics, $questionid, $item);
+                    if ($value === null) {
+                        continue;
+                    }
+
+                    $counts[$questionid][$item] += 1;
+                    $sums[$questionid][$item] += $value;
+                }
+            }
+        }
+
+        // Compute the averages from the final totals.
+        $aggregates = [];
+        foreach ($questionids as $questionid) {
+            $aggregates[$questionid] = [];
+            foreach ($requiredstatistics as $item) {
+                if ($counts[$questionid][$item] > 0) {
+                    $aggregates[$questionid][$item] = $sums[$questionid][$item] / $counts[$questionid][$item];
+                } else {
+                    $aggregates[$questionid][$item] = null;
+                }
+
+            }
+        }
+
+        return $aggregates;
+    }
+
+    /**
+     * For a list of questions find all the places, defined by (component, contextid), where there are attempts.
+     *
+     * @param int[] $questionids array of question ids that we are interested in.
+     * @return \stdClass[] list of objects with fields ->component and ->contextid.
+     */
+    protected static function get_all_places_where_questions_were_attempted(array $questionids): array {
+        global $DB;
+
+        [$questionidcondition, $params] = $DB->get_in_or_equal($questionids);
+        // The MIN(qu.id) is just to ensure that the rows have a unique key.
+        $places = $DB->get_records_sql("
+                SELECT MIN(qu.id) AS somethingunique, qu.component, qu.contextid
+                  FROM {question_usages} qu
+                  JOIN {question_attempts} qatt ON qatt.questionusageid = qu.id
+                  JOIN {context} ctx ON ctx.id = qu.contextid
+                 WHERE qatt.questionid $questionidcondition
+              GROUP BY qu.component, qu.contextid
+              ORDER BY qu.contextid ASC
+                ", $params);
+
+        // Strip out the unwanted ids.
+        $places = array_values($places);
+        foreach ($places as $place) {
+            unset($place->somethingunique);
+        }
+
+        return $places;
+    }
+
+    /**
+     * Load the question statistics for all the attempts belonging to a particular component in a particular context.
+     *
+     * @param string $component frankenstyle component name, e.g. 'mod_quiz'.
+     * @param \context $context the context to load the statistics for.
+     * @return all_calculated_for_qubaid_condition|null question statistics.
+     */
+    protected static function load_statistics_for_place(
+        string $component,
+        \context $context
+    ): ?all_calculated_for_qubaid_condition {
+        // This check is basically if (component_exists).
+        if (empty(core_component::get_component_directory($component))) {
+            return null;
+        }
+
+        if (!component_callback_exists($component, 'calculate_question_stats')) {
+            return null;
+        }
+
+        return component_callback($component, 'calculate_question_stats', [$context]);
+    }
+
+    /**
+     * Extract the value for one question and one type of statistic from a set of statistics.
+     *
+     * @param all_calculated_for_qubaid_condition $statistics the batch of statistics.
+     * @param int $questionid a question id.
+     * @param string $item one of the field names in all_calculated_for_qubaid_condition, e.g. 'facility'.
+     * @return float|null the required value.
+     */
+    protected static function extract_item_value(all_calculated_for_qubaid_condition $statistics,
+            int $questionid, string $item): ?float {
+
+        // Look in main questions.
+        foreach ($statistics->questionstats as $stats) {
+            if ($stats->questionid == $questionid && isset($stats->$item)) {
+                return $stats->$item;
+            }
+        }
+
+        // If not found, look in sub questions.
+        foreach ($statistics->subquestionstats as $stats) {
+            if ($stats->questionid == $questionid && isset($stats->$item)) {
+                return $stats->$item;
+            }
+        }
+
+        return null;
+    }
+}