first commit

lib/classes/navigation/output/more_menu.php

@@ -0,0 +1,92 @@
+<?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\navigation\output;
+
+use renderable;
+use renderer_base;
+use templatable;
+use custom_menu;
+
+/**
+ * more menu navigation renderable
+ *
+ * @package     core
+ * @category    navigation
+ * @copyright   2021 onwards Adrian Greeve
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class more_menu implements renderable, templatable {
+
+    protected $content;
+    protected $navbarstyle;
+    protected $haschildren;
+    protected $istablist;
+
+    /**
+     * Constructor for this class.
+     *
+     * @param object $content Navigation objects.
+     * @param string $navbarstyle class name.
+     * @param bool $haschildren The content has children.
+     * @param bool $istablist When true, the more menu should be rendered and behave with a tablist ARIA role.
+     *                        If false, it's rendered with a menubar ARIA role. Defaults to false.
+     */
+    public function __construct(object $content, string $navbarstyle, bool $haschildren = true, bool $istablist = false) {
+        $this->content = $content;
+        $this->navbarstyle = $navbarstyle;
+        $this->haschildren = $haschildren;
+        $this->istablist = $istablist;
+    }
+
+    /**
+     * Return data for rendering a template.
+     *
+     * @param renderer_base $output The output
+     * @return array Data for rendering a template
+     */
+    public function export_for_template(renderer_base $output): array {
+        $data = [
+            'navbarstyle' => $this->navbarstyle,
+            'istablist' => $this->istablist,
+        ];
+        if ($this->haschildren) {
+            // The node collection doesn't have anything to render so exit now.
+            if (!isset($this->content->children) || count($this->content->children) == 0) {
+                return [];
+            }
+            // Find all nodes that have children and are defined to show the children in a submenu.
+            // For each of these nodes we would like to display a dropdown menu and in order to achieve that
+            // (as required by the template) we need to set the node's property 'moremenuid' to a new unique value and
+            // 'haschildren' to true.
+            foreach ($this->content->children as &$item) {
+                if ($item->showchildreninsubmenu && isset($this->content->children) &&
+                        count($this->content->children) > 0) {
+                    $item->moremenuid = uniqid();
+                    $item->haschildren = true;
+                }
+            }
+
+            $data['nodecollection'] = $this->content;
+        } else {
+            $data['nodearray'] = (array) $this->content;
+        }
+        $data['moremenuid'] = uniqid();
+
+        return $data;
+    }
+
+}

lib/classes/navigation/output/primary.php

@@ -0,0 +1,357 @@
+<?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\navigation\output;
+
+use renderable;
+use renderer_base;
+use templatable;
+use custom_menu;
+
+/**
+ * Primary navigation renderable
+ *
+ * This file combines primary nav, custom menu, lang menu and
+ * usermenu into a standardized format for the frontend
+ *
+ * @package     core
+ * @category    navigation
+ * @copyright   2021 onwards Peter Dias
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class primary implements renderable, templatable {
+    /** @var \moodle_page $page the moodle page that the navigation belongs to */
+    private $page = null;
+
+    /**
+     * primary constructor.
+     * @param \moodle_page $page
+     */
+    public function __construct($page) {
+        $this->page = $page;
+    }
+
+    /**
+     * Combine the various menus into a standardized output.
+     *
+     * @param renderer_base|null $output
+     * @return array
+     */
+    public function export_for_template(?renderer_base $output = null): array {
+        if (!$output) {
+            $output = $this->page->get_renderer('core');
+        }
+
+        $menudata = (object) $this->merge_primary_and_custom($this->get_primary_nav(), $this->get_custom_menu($output));
+        $moremenu = new \core\navigation\output\more_menu($menudata, 'navbar-nav', false);
+        $mobileprimarynav = $this->merge_primary_and_custom($this->get_primary_nav(), $this->get_custom_menu($output), true);
+
+        $languagemenu = new \core\output\language_menu($this->page);
+
+        return [
+            'mobileprimarynav' => $mobileprimarynav,
+            'moremenu' => $moremenu->export_for_template($output),
+            'lang' => !isloggedin() || isguestuser() ? $languagemenu->export_for_template($output) : [],
+            'user' => $this->get_user_menu($output),
+        ];
+    }
+
+    /**
+     * Get the primary nav object and standardize the output
+     *
+     * @param \navigation_node|null $parent used for nested nodes, by default the primarynav node
+     * @return array
+     */
+    protected function get_primary_nav($parent = null): array {
+        if ($parent === null) {
+            $parent = $this->page->primarynav;
+        }
+        $nodes = [];
+        foreach ($parent->children as $node) {
+            $children = $this->get_primary_nav($node);
+            $activechildren = array_filter($children, function($child) {
+                return !empty($child['isactive']);
+            });
+            if ($node->preceedwithhr && count($nodes) && empty($nodes[count($nodes) - 1]['divider'])) {
+                $nodes[] = ['divider' => true];
+            }
+            $nodes[] = [
+                'title' => $node->get_title(),
+                'url' => $node->action(),
+                'text' => $node->text,
+                'icon' => $node->icon,
+                'isactive' => $node->isactive || !empty($activechildren),
+                'key' => $node->key,
+                'children' => $children,
+                'haschildren' => !empty($children) ? 1 : 0,
+            ];
+        }
+
+        return $nodes;
+    }
+
+    /**
+     * Custom menu items reside on the same level as the original nodes.
+     * Fetch and convert the nodes to a standardised array.
+     *
+     * @param renderer_base $output
+     * @return array
+     */
+    protected function get_custom_menu(renderer_base $output): array {
+        global $CFG;
+
+        // Early return if a custom menu does not exists.
+        if (empty($CFG->custommenuitems)) {
+            return [];
+        }
+
+        $custommenuitems = $CFG->custommenuitems;
+        $currentlang = current_language();
+        $custommenunodes = custom_menu::convert_text_to_menu_nodes($custommenuitems, $currentlang);
+        $nodes = [];
+        foreach ($custommenunodes as $node) {
+            $nodes[] = $node->export_for_template($output);
+        }
+
+        return $nodes;
+    }
+
+    /**
+     * When defining custom menu items, the active flag is not obvserved correctly. Therefore, the merge of the primary
+     * and custom navigation must be handled a bit smarter. Change the "isactive" flag of the nodes (this may set by
+     * default in the primary nav nodes but is entirely missing in the custom nav nodes).
+     * Set the $expandedmenu argument to true when the menu for the mobile template is build.
+     *
+     * @param array $primary
+     * @param array $custom
+     * @param bool $expandedmenu
+     * @return array
+     */
+    protected function merge_primary_and_custom(array $primary, array $custom, bool $expandedmenu = false): array {
+        if (empty($custom)) {
+            return $primary; // No custom nav, nothing to merge.
+        }
+        // Remember the amount of primary nodes and whether we changed the active flag in the custom menu nodes.
+        $primarylen = count($primary);
+        $changed = false;
+        foreach (array_keys($custom) as $i) {
+            if (!$changed) {
+                if ($this->flag_active_nodes($custom[$i], $expandedmenu)) {
+                    $changed = true;
+                }
+            }
+            $primary[] = $custom[$i];
+        }
+        // In case some custom node is active, mark all primary nav elements as inactive.
+        if ($changed) {
+            for ($i = 0; $i < $primarylen; $i++) {
+                $primary[$i]['isactive'] = false;
+            }
+        }
+        return $primary;
+    }
+
+    /**
+     * Recursive checks if any of the children is active. If that's the case this node (the parent) is active as
+     * well. If the node has no children, check if the node itself is active. Use pass by reference for the node
+     * object because we actively change/set the "isactive" flag inside the method and this needs to be kept at the
+     * callers side.
+     * Set $expandedmenu to true, if the mobile menu is done, in this case the active flag gets the node that is
+     * actually active, while the parent hierarchy of the active node gets the flag isopen.
+     *
+     * @param object $node
+     * @param bool $expandedmenu
+     * @return bool
+     */
+    protected function flag_active_nodes(object $node, bool $expandedmenu = false): bool {
+        global $FULLME;
+        $active = false;
+        foreach (array_keys($node->children ?? []) as $c) {
+            if ($this->flag_active_nodes($node->children[$c], $expandedmenu)) {
+                $active = true;
+            }
+        }
+        // One of the children is active, so this node (the parent) is active as well.
+        if ($active) {
+            if ($expandedmenu) {
+                $node->isopen = true;
+            } else {
+                $node->isactive = true;
+            }
+            return true;
+        }
+
+        // By default, the menu item node to check is not active.
+        $node->isactive = false;
+
+        // Check if the node url matches the called url. The node url may omit the trailing index.php, therefore check
+        // this as well.
+        if (empty($node->url)) {
+            // Current menu node has no url set, so it can't be active.
+            return false;
+        }
+        $nodeurl = parse_url($node->url);
+        $current = parse_url($FULLME ?? '');
+
+        $pathmatches = false;
+
+        // Exact match of the path of node and current url.
+        $nodepath = $nodeurl['path'] ?? '/';
+        $currentpath = $current['path'] ?? '/';
+        if ($nodepath === $currentpath) {
+            $pathmatches = true;
+        }
+        // The current url may be trailed by a index.php, otherwise it's the same as the node path.
+        if (!$pathmatches && $nodepath . 'index.php' === $currentpath) {
+            $pathmatches = true;
+        }
+        // No path did match, so the node can't be active.
+        if (!$pathmatches) {
+            return false;
+        }
+        // We are here because the path matches, so now look at the query string.
+        $nodequery = $nodeurl['query'] ?? '';
+        $currentquery = $current['query'] ?? '';
+        // If the node has no query string defined, then the patch match is sufficient.
+        if (empty($nodeurl['query'])) {
+            $node->isactive = true;
+            return true;
+        }
+        // If the node contains a query string then also the current url must match this query.
+        if ($nodequery === $currentquery) {
+            $node->isactive = true;
+        }
+        return $node->isactive;
+    }
+
+    /**
+     * Get/Generate the user menu.
+     *
+     * This is leveraging the data from user_get_user_navigation_info and the logic in $OUTPUT->user_menu()
+     *
+     * @param renderer_base $output
+     * @return array
+     */
+    public function get_user_menu(renderer_base $output): array {
+        global $CFG, $USER, $PAGE;
+        require_once($CFG->dirroot . '/user/lib.php');
+
+        $usermenudata = [];
+        $submenusdata = [];
+        $info = user_get_user_navigation_info($USER, $PAGE);
+        if (isset($info->unauthenticateduser)) {
+            $info->unauthenticateduser['content'] = get_string($info->unauthenticateduser['content']);
+            $info->unauthenticateduser['url'] = get_login_url();
+            return (array) $info;
+        }
+        // Gather all the avatar data to be displayed in the user menu.
+        $usermenudata['avatardata'][] = [
+            'content' => $info->metadata['useravatar'],
+            'classes' => 'current'
+        ];
+        $usermenudata['userfullname'] = $info->metadata['realuserfullname'] ?? $info->metadata['userfullname'];
+
+        // Logged in as someone else.
+        if ($info->metadata['asotheruser']) {
+            $usermenudata['avatardata'][] = [
+                'content' => $info->metadata['realuseravatar'],
+                'classes' => 'realuser'
+            ];
+            $usermenudata['metadata'][] = [
+                'content' => get_string('loggedinas', 'moodle', $info->metadata['userfullname']),
+                'classes' => 'viewingas'
+            ];
+        }
+
+        // Gather all the meta data to be displayed in the user menu.
+        $metadata = [
+            'asotherrole' => [
+                'value' => 'rolename',
+                'class' => 'role role-##GENERATEDCLASS##',
+            ],
+            'userloginfail' => [
+                'value' => 'userloginfail',
+                'class' => 'loginfailures',
+            ],
+            'asmnetuser' => [
+                'value' => 'mnetidprovidername',
+                'class' => 'mnet mnet-##GENERATEDCLASS##',
+            ],
+        ];
+        foreach ($metadata as $key => $value) {
+            if (!empty($info->metadata[$key])) {
+                $content = $info->metadata[$value['value']] ?? '';
+                $generatedclass = strtolower(preg_replace('#[ ]+#', '-', trim($content)));
+                $customclass = str_replace('##GENERATEDCLASS##', $generatedclass, ($value['class'] ?? ''));
+                $usermenudata['metadata'][] = [
+                    'content' => $content,
+                    'classes' => $customclass
+                ];
+            }
+        }
+
+        $modifiedarray = array_map(function($value) {
+            $value->divider = $value->itemtype == 'divider';
+            $value->link = $value->itemtype == 'link';
+            if (isset($value->pix) && !empty($value->pix)) {
+                $value->pixicon = $value->pix;
+                unset($value->pix);
+            }
+            return $value;
+        }, $info->navitems);
+
+        // Include the language menu as a submenu within the user menu.
+        $languagemenu = new \core\output\language_menu($this->page);
+        $langmenu = $languagemenu->export_for_template($output);
+        if (!empty($langmenu)) {
+            $languageitems = $langmenu['items'];
+            // If there are available languages, generate the data for the the language selector submenu.
+            if (!empty($languageitems)) {
+                $langsubmenuid = uniqid();
+                // Generate the data for the link to language selector submenu.
+                $language = (object) [
+                    'itemtype' => 'submenu-link',
+                    'submenuid' => $langsubmenuid,
+                    'title' => get_string('language'),
+                    'divider' => false,
+                    'submenulink' => true,
+                ];
+
+                // Place the link before the 'Log out' menu item which is either the last item in the menu or
+                // second to last when 'Switch roles' is available.
+                $menuposition = count($modifiedarray) - 1;
+                if (has_capability('moodle/role:switchroles', $PAGE->context)) {
+                    $menuposition = count($modifiedarray) - 2;
+                }
+                array_splice($modifiedarray, $menuposition, 0, [$language]);
+
+                // Generate the data for the language selector submenu.
+                $submenusdata[] = (object)[
+                    'id' => $langsubmenuid,
+                    'title' => get_string('languageselector'),
+                    'items' => $languageitems,
+                ];
+            }
+        }
+
+        // Add divider before the last item.
+        $modifiedarray[count($modifiedarray) - 2]->divider = true;
+        $usermenudata['items'] = $modifiedarray;
+        $usermenudata['submenus'] = array_values($submenusdata);
+
+        return $usermenudata;
+    }
+}

lib/classes/navigation/views/primary.php

@@ -0,0 +1,197 @@
+<?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\navigation\views;
+
+use navigation_node;
+
+/**
+ * Class primary.
+ *
+ * The primary navigation view is a combination of few components - navigation, output->navbar,
+ *
+ * @package     core
+ * @category    navigation
+ * @copyright   2021 onwards Peter Dias
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class primary extends view {
+    /**
+     * Initialise the primary navigation node
+     */
+    public function initialise(): void {
+        global $CFG;
+
+        if (during_initial_install() || $this->initialised) {
+            return;
+        }
+        $this->id = 'primary_navigation';
+
+        $showhomenode = empty($this->page->theme->removedprimarynavitems) ||
+            !in_array('home', $this->page->theme->removedprimarynavitems);
+        // We do not need to change the text for the home/dashboard depending on the set homepage.
+        if ($showhomenode) {
+            $sitehome = $this->add(get_string('home'), new \moodle_url('/'), self::TYPE_SYSTEM,
+                null, 'home', new \pix_icon('i/home', ''));
+        }
+        if (isloggedin() && !isguestuser()) {
+            $homepage = get_home_page();
+            if ($homepage == HOMEPAGE_MY || $homepage == HOMEPAGE_MYCOURSES) {
+                // We need to stop automatic redirection.
+                if ($showhomenode) {
+                    $sitehome->action->param('redirect', '0');
+                }
+            }
+
+            // Add the dashboard link.
+            $showmyhomenode = !empty($CFG->enabledashboard) && (empty($this->page->theme->removedprimarynavitems) ||
+                !in_array('myhome', $this->page->theme->removedprimarynavitems));
+            if ($showmyhomenode) {
+                $this->add(get_string('myhome'), new \moodle_url('/my/'),
+                    self::TYPE_SETTING, null, 'myhome', new \pix_icon('i/dashboard', ''));
+            }
+
+            // Add the mycourses link.
+            $showcoursesnode = empty($this->page->theme->removedprimarynavitems) ||
+                !in_array('courses', $this->page->theme->removedprimarynavitems);
+            if ($showcoursesnode) {
+                $this->add(get_string('mycourses'), new \moodle_url('/my/courses.php'), self::TYPE_ROOTNODE, null, 'mycourses');
+            }
+        }
+
+        $showsiteadminnode = empty($this->page->theme->removedprimarynavitems) ||
+            !in_array('siteadminnode', $this->page->theme->removedprimarynavitems);
+
+        if ($showsiteadminnode && $node = $this->get_site_admin_node()) {
+            // We don't need everything from the node just the initial link.
+            $this->add($node->text, $node->action(), self::TYPE_SITE_ADMIN, null, 'siteadminnode', $node->icon);
+        }
+
+        // Allow plugins to add nodes to the primary navigation.
+        $hook = new \core\hook\navigation\primary_extend($this);
+        \core\di::get(\core\hook\manager::class)->dispatch($hook);
+
+        // Search and set the active node.
+        $this->set_active_node();
+        $this->initialised = true;
+    }
+
+    /**
+     * Get the site admin node if available.
+     *
+     * @return navigation_node|null
+     */
+    private function get_site_admin_node(): ?navigation_node {
+        // Add the site admin node. We are using the settingsnav so as to avoid rechecking permissions again.
+        $settingsnav = $this->page->settingsnav;
+        $node = $settingsnav->find('siteadministration', self::TYPE_SITE_ADMIN);
+        if (!$node) {
+            // Try again. This node can exist with 2 different keys.
+            $node = $settingsnav->find('root', self::TYPE_SITE_ADMIN);
+        }
+
+        return $node ?: null;
+    }
+
+    /**
+     * Find and set the active node. Initially searches based on URL/explicitly set active node.
+     * If nothing is found, it checks the following:
+     *      - If the node is a site page, set 'Home' as active
+     *      - If within a course context, set 'My courses' as active
+     *      - If within a course category context, set 'Site Admin' (if available) else set 'Home'
+     *      - Else if available set site admin as active
+     *      - Fallback, set 'Home' as active
+     */
+    private function set_active_node(): void {
+        global $SITE;
+        $activenode = $this->search_and_set_active_node($this);
+        // If we haven't found an active node based on the standard search. Follow the criteria above.
+        if (!$activenode) {
+            $children = $this->get_children_key_list();
+            $navactivenode = $this->page->navigation->find_active_node();
+            $activekey = 'home';
+            if (isset($navactivenode->parent) && $navactivenode->parent->text == get_string('sitepages')) {
+                $activekey = 'home';
+            } else if (in_array($this->context->contextlevel, [CONTEXT_COURSE, CONTEXT_MODULE])) {
+                if ($this->page->course->id != $SITE->id) {
+                    $activekey = 'courses';
+                }
+            } else if (in_array('siteadminnode', $children) && $node = $this->get_site_admin_node()) {
+                if ($this->context->contextlevel == CONTEXT_COURSECAT || $node->search_for_active_node(URL_MATCH_EXACT)) {
+                    $activekey = 'siteadminnode';
+                }
+            }
+
+            if ($activekey && $activenode = $this->find($activekey, null)) {
+                $activenode->make_active();
+            }
+        }
+    }
+
+    /**
+     * Searches all children for the matching active node
+     *
+     * This method recursively traverse through the node tree to
+     * find the node to activate/highlight:
+     * 1. If the user had set primary node key to highlight, it
+     *    tries to match this key with the node(s). Hence it would
+     *    travel all the nodes.
+     * 2. If no primary key is provided by the dev, then it would
+     *    check for the active node set in the tree.
+     *
+     * @param navigation_node $node
+     * @param array $actionnodes navigation nodes array to set active and inactive.
+     * @return navigation_node|null
+     */
+    private function search_and_set_active_node(navigation_node $node,
+        array &$actionnodes = []): ?navigation_node {
+        global $PAGE;
+
+        $activekey = $PAGE->get_primary_activate_tab();
+        if ($activekey) {
+            if ($node->key && ($activekey === $node->key)) {
+                return $node;
+            }
+        } else if ($node->check_if_active()) {
+            return $node;
+        }
+
+        foreach ($node->children as $child) {
+            $outcome = $this->search_and_set_active_node($child, $actionnodes);
+            if ($outcome !== null) {
+                $outcome->make_active();
+                $actionnodes['active'] = $outcome;
+                if ($activekey === null) {
+                    return $actionnodes['active'];
+                }
+            } else {
+                // If the child is active then make it inactive.
+                if ($child->isactive) {
+                    $actionnodes['set_inactive'][] = $child;
+                }
+            }
+        }
+
+        // If we have successfully found an active node then reset any other nodes to inactive.
+        if (isset($actionnodes['set_inactive']) && isset($actionnodes['active'])) {
+            foreach ($actionnodes['set_inactive'] as $inactivenode) {
+                $inactivenode->make_inactive();
+            }
+            $actionnodes['set_inactive'] = [];
+        }
+        return ($actionnodes['active'] ?? null);
+    }
+}

lib/classes/navigation/views/view.php

@@ -0,0 +1,153 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace core\navigation\views;
+
+use navigation_node;
+use navigation_node_collection;
+
+/**
+ * Class view.
+ *
+ * The base view class which expands on the navigation_node,
+ *
+ * @package     core
+ * @category    navigation
+ * @copyright   2021 onwards Peter Dias
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+abstract class view extends navigation_node {
+    /** @var \stdClass $context the current context */
+    protected $context;
+    /** @var \moodle_page $page the moodle page that the navigation belongs to */
+    protected $page;
+    /** @var bool $initialised A switch to see if the navigation node is initialised */
+    protected $initialised = false;
+    /** @var navigation_node $activenode A string identifier for the active node*/
+    public $activenode;
+
+    /**
+     * Function to initialise the respective view
+     * @return void
+     */
+    abstract public function initialise(): void;
+
+    /**
+     * navigation constructor.
+     * @param \moodle_page $page
+     */
+    public function __construct(\moodle_page $page) {
+        global $FULLME;
+
+        if (during_initial_install()) {
+            return false;
+        }
+
+        $this->page = $page;
+        $this->context = $this->page->context;
+        $this->children = new navigation_node_collection();
+    }
+
+    /**
+     * Get the leaf nodes for the nav view
+     *
+     * @param navigation_node $source The settingsnav OR navigation object
+     * @param array $nodes An array of nodes to fetch from the source which specifies the node type and final order
+     * @return array $nodesordered The fetched nodes ordered based on final specification.
+     */
+    protected function get_leaf_nodes(navigation_node $source, array $nodes): array {
+        $nodesordered = [];
+        foreach ($nodes as $type => $leaves) {
+            foreach ($leaves as $leaf => $location) {
+                if ($node = $source->find($leaf, $type)) {
+                    $nodesordered["$location"] = $nodesordered["$location"] ?? $node;
+                }
+            }
+        }
+
+        return $nodesordered;
+    }
+
+    /**
+     * Scan the given node for the active node. It starts first with a strict search and then switches to a base search if
+     * required.
+     *
+     * @param navigation_node $node The node to scan.
+     * @return navigation_node|null The active node or null.
+     */
+    protected function scan_for_active_node(navigation_node $node): ?navigation_node {
+        $result = $this->active_node_scan($node);
+        if (!is_null($result)) {
+            return $result;
+        } else {
+            return $this->active_node_scan($node, URL_MATCH_BASE);
+        }
+    }
+
+    /**
+     * This function recursively scans nodes until it finds the active node or there
+     * are no more nodes. We are using a custom implementation here to adjust the strictness
+     * and also because we need the parent node and not the specific child node in the new views.
+     * e.g. Structure for site admin,
+     *      SecondaryNav
+     *          - Site Admin
+     *          - Users
+     *              - User policies
+     *          - Courses
+     * In the above example, if we are on the 'User Policies' page, the active node should be 'Users'
+     *
+     * @param navigation_node $node
+     * @param int $strictness How stict to be with the scan for the active node.
+     * @return navigation_node|null
+     */
+    protected function active_node_scan(navigation_node $node,
+        int $strictness = URL_MATCH_EXACT): ?navigation_node {
+
+        $result = null;
+        $activekey = $this->page->get_secondary_active_tab();
+        if ($activekey) {
+            if ($node->key && $activekey === $node->key) {
+                return $node;
+            }
+        } else if ($node->check_if_active($strictness)) {
+            return $node; // No need to continue, exit function.
+        }
+
+        foreach ($node->children as $child) {
+            if ($this->active_node_scan($child, $strictness)) {
+                // If node is one of the new views then set the active node to the child.
+                if (!$node instanceof view) {
+                    $node->make_active();
+                    $result = $node;
+                } else {
+                    $child->make_active();
+                    $this->activenode = $child;
+                    $result = $child;
+                }
+
+                // If the secondary active tab not set then just return the result (fallback).
+                if ($activekey === null) {
+                    return $result;
+                }
+            } else {
+                // Make sure to reset the active state.
+                $child->make_inactive();
+            }
+        }
+
+        return $result;
+    }
+}