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See Release Notes

  • Bug fixes for general core bugs in 3.11.x will end 14 Nov 2022 (12 months plus 6 months extension).
  • Bug fixes for security issues in 3.11.x will end 13 Nov 2023 (18 months plus 12 months extension).
  • PHP version: minimum PHP 7.3.0 Note: minimum PHP version has increased since Moodle 3.10. PHP 7.4.x is supported too.

Differences Between: [Versions 310 and 311] [Versions 311 and 400] [Versions 311 and 401] [Versions 38 and 311] [Versions 39 and 311]

   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * This file contains classes used to manage the navigation structures within Moodle.
  19   *
  20   * @since      Moodle 2.0
  21   * @package    core
  22   * @copyright  2009 Sam Hemelryk
  23   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24   */
  25  
  26  defined('MOODLE_INTERNAL') || die();
  27  
  28  /**
  29   * The name that will be used to separate the navigation cache within SESSION
  30   */
  31  define('NAVIGATION_CACHE_NAME', 'navigation');
  32  define('NAVIGATION_SITE_ADMIN_CACHE_NAME', 'navigationsiteadmin');
  33  
  34  /**
  35   * This class is used to represent a node in a navigation tree
  36   *
  37   * This class is used to represent a node in a navigation tree within Moodle,
  38   * the tree could be one of global navigation, settings navigation, or the navbar.
  39   * Each node can be one of two types either a Leaf (default) or a branch.
  40   * When a node is first created it is created as a leaf, when/if children are added
  41   * the node then becomes a branch.
  42   *
  43   * @package   core
  44   * @category  navigation
  45   * @copyright 2009 Sam Hemelryk
  46   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  47   */
  48  class navigation_node implements renderable {
  49      /** @var int Used to identify this node a leaf (default) 0 */
  50      const NODETYPE_LEAF =   0;
  51      /** @var int Used to identify this node a branch, happens with children  1 */
  52      const NODETYPE_BRANCH = 1;
  53      /** @var null Unknown node type null */
  54      const TYPE_UNKNOWN =    null;
  55      /** @var int System node type 0 */
  56      const TYPE_ROOTNODE =   0;
  57      /** @var int System node type 1 */
  58      const TYPE_SYSTEM =     1;
  59      /** @var int Category node type 10 */
  60      const TYPE_CATEGORY =   10;
  61      /** var int Category displayed in MyHome navigation node */
  62      const TYPE_MY_CATEGORY = 11;
  63      /** @var int Course node type 20 */
  64      const TYPE_COURSE =     20;
  65      /** @var int Course Structure node type 30 */
  66      const TYPE_SECTION =    30;
  67      /** @var int Activity node type, e.g. Forum, Quiz 40 */
  68      const TYPE_ACTIVITY =   40;
  69      /** @var int Resource node type, e.g. Link to a file, or label 50 */
  70      const TYPE_RESOURCE =   50;
  71      /** @var int A custom node type, default when adding without specifing type 60 */
  72      const TYPE_CUSTOM =     60;
  73      /** @var int Setting node type, used only within settings nav 70 */
  74      const TYPE_SETTING =    70;
  75      /** @var int site admin branch node type, used only within settings nav 71 */
  76      const TYPE_SITE_ADMIN = 71;
  77      /** @var int Setting node type, used only within settings nav 80 */
  78      const TYPE_USER =       80;
  79      /** @var int Setting node type, used for containers of no importance 90 */
  80      const TYPE_CONTAINER =  90;
  81      /** var int Course the current user is not enrolled in */
  82      const COURSE_OTHER = 0;
  83      /** var int Course the current user is enrolled in but not viewing */
  84      const COURSE_MY = 1;
  85      /** var int Course the current user is currently viewing */
  86      const COURSE_CURRENT = 2;
  87      /** var string The course index page navigation node */
  88      const COURSE_INDEX_PAGE = 'courseindexpage';
  89  
  90      /** @var int Parameter to aid the coder in tracking [optional] */
  91      public $id = null;
  92      /** @var string|int The identifier for the node, used to retrieve the node */
  93      public $key = null;
  94      /** @var string The text to use for the node */
  95      public $text = null;
  96      /** @var string Short text to use if requested [optional] */
  97      public $shorttext = null;
  98      /** @var string The title attribute for an action if one is defined */
  99      public $title = null;
 100      /** @var string A string that can be used to build a help button */
 101      public $helpbutton = null;
 102      /** @var moodle_url|action_link|null An action for the node (link) */
 103      public $action = null;
 104      /** @var pix_icon The path to an icon to use for this node */
 105      public $icon = null;
 106      /** @var int See TYPE_* constants defined for this class */
 107      public $type = self::TYPE_UNKNOWN;
 108      /** @var int See NODETYPE_* constants defined for this class */
 109      public $nodetype = self::NODETYPE_LEAF;
 110      /** @var bool If set to true the node will be collapsed by default */
 111      public $collapse = false;
 112      /** @var bool If set to true the node will be expanded by default */
 113      public $forceopen = false;
 114      /** @var array An array of CSS classes for the node */
 115      public $classes = array();
 116      /** @var navigation_node_collection An array of child nodes */
 117      public $children = array();
 118      /** @var bool If set to true the node will be recognised as active */
 119      public $isactive = false;
 120      /** @var bool If set to true the node will be dimmed */
 121      public $hidden = false;
 122      /** @var bool If set to false the node will not be displayed */
 123      public $display = true;
 124      /** @var bool If set to true then an HR will be printed before the node */
 125      public $preceedwithhr = false;
 126      /** @var bool If set to true the the navigation bar should ignore this node */
 127      public $mainnavonly = false;
 128      /** @var bool If set to true a title will be added to the action no matter what */
 129      public $forcetitle = false;
 130      /** @var navigation_node A reference to the node parent, you should never set this directly you should always call set_parent */
 131      public $parent = null;
 132      /** @var bool Override to not display the icon even if one is provided **/
 133      public $hideicon = false;
 134      /** @var bool Set to true if we KNOW that this node can be expanded.  */
 135      public $isexpandable = false;
 136      /** @var array */
 137      protected $namedtypes = array(0 => 'system', 10 => 'category', 20 => 'course', 30 => 'structure', 40 => 'activity',
 138                                    50 => 'resource', 60 => 'custom', 70 => 'setting', 71 => 'siteadmin', 80 => 'user',
 139                                    90 => 'container');
 140      /** @var moodle_url */
 141      protected static $fullmeurl = null;
 142      /** @var bool toogles auto matching of active node */
 143      public static $autofindactive = true;
 144      /** @var bool should we load full admin tree or rely on AJAX for performance reasons */
 145      protected static $loadadmintree = false;
 146      /** @var mixed If set to an int, that section will be included even if it has no activities */
 147      public $includesectionnum = false;
 148      /** @var bool does the node need to be loaded via ajax */
 149      public $requiresajaxloading = false;
 150      /** @var bool If set to true this node will be added to the "flat" navigation */
 151      public $showinflatnavigation = false;
 152  
 153      /**
 154       * Constructs a new navigation_node
 155       *
 156       * @param array|string $properties Either an array of properties or a string to use
 157       *                     as the text for the node
 158       */
 159      public function __construct($properties) {
 160          if (is_array($properties)) {
 161              // Check the array for each property that we allow to set at construction.
 162              // text         - The main content for the node
 163              // shorttext    - A short text if required for the node
 164              // icon         - The icon to display for the node
 165              // type         - The type of the node
 166              // key          - The key to use to identify the node
 167              // parent       - A reference to the nodes parent
 168              // action       - The action to attribute to this node, usually a URL to link to
 169              if (array_key_exists('text', $properties)) {
 170                  $this->text = $properties['text'];
 171              }
 172              if (array_key_exists('shorttext', $properties)) {
 173                  $this->shorttext = $properties['shorttext'];
 174              }
 175              if (!array_key_exists('icon', $properties)) {
 176                  $properties['icon'] = new pix_icon('i/navigationitem', '');
 177              }
 178              $this->icon = $properties['icon'];
 179              if ($this->icon instanceof pix_icon) {
 180                  if (empty($this->icon->attributes['class'])) {
 181                      $this->icon->attributes['class'] = 'navicon';
 182                  } else {
 183                      $this->icon->attributes['class'] .= ' navicon';
 184                  }
 185              }
 186              if (array_key_exists('type', $properties)) {
 187                  $this->type = $properties['type'];
 188              } else {
 189                  $this->type = self::TYPE_CUSTOM;
 190              }
 191              if (array_key_exists('key', $properties)) {
 192                  $this->key = $properties['key'];
 193              }
 194              // This needs to happen last because of the check_if_active call that occurs
 195              if (array_key_exists('action', $properties)) {
 196                  $this->action = $properties['action'];
 197                  if (is_string($this->action)) {
 198                      $this->action = new moodle_url($this->action);
 199                  }
 200                  if (self::$autofindactive) {
 201                      $this->check_if_active();
 202                  }
 203              }
 204              if (array_key_exists('parent', $properties)) {
 205                  $this->set_parent($properties['parent']);
 206              }
 207          } else if (is_string($properties)) {
 208              $this->text = $properties;
 209          }
 210          if ($this->text === null) {
 211              throw new coding_exception('You must set the text for the node when you create it.');
 212          }
 213          // Instantiate a new navigation node collection for this nodes children
 214          $this->children = new navigation_node_collection();
 215      }
 216  
 217      /**
 218       * Checks if this node is the active node.
 219       *
 220       * This is determined by comparing the action for the node against the
 221       * defined URL for the page. A match will see this node marked as active.
 222       *
 223       * @param int $strength One of URL_MATCH_EXACT, URL_MATCH_PARAMS, or URL_MATCH_BASE
 224       * @return bool
 225       */
 226      public function check_if_active($strength=URL_MATCH_EXACT) {
 227          global $FULLME, $PAGE;
 228          // Set fullmeurl if it hasn't already been set
 229          if (self::$fullmeurl == null) {
 230              if ($PAGE->has_set_url()) {
 231                  self::override_active_url(new moodle_url($PAGE->url));
 232              } else {
 233                  self::override_active_url(new moodle_url($FULLME));
 234              }
 235          }
 236  
 237          // Compare the action of this node against the fullmeurl
 238          if ($this->action instanceof moodle_url && $this->action->compare(self::$fullmeurl, $strength)) {
 239              $this->make_active();
 240              return true;
 241          }
 242          return false;
 243      }
 244  
 245      /**
 246       * True if this nav node has siblings in the tree.
 247       *
 248       * @return bool
 249       */
 250      public function has_siblings() {
 251          if (empty($this->parent) || empty($this->parent->children)) {
 252              return false;
 253          }
 254          if ($this->parent->children instanceof navigation_node_collection) {
 255              $count = $this->parent->children->count();
 256          } else {
 257              $count = count($this->parent->children);
 258          }
 259          return ($count > 1);
 260      }
 261  
 262      /**
 263       * Get a list of sibling navigation nodes at the same level as this one.
 264       *
 265       * @return bool|array of navigation_node
 266       */
 267      public function get_siblings() {
 268          // Returns a list of the siblings of the current node for display in a flat navigation element. Either
 269          // the in-page links or the breadcrumb links.
 270          $siblings = false;
 271  
 272          if ($this->has_siblings()) {
 273              $siblings = [];
 274              foreach ($this->parent->children as $child) {
 275                  if ($child->display) {
 276                      $siblings[] = $child;
 277                  }
 278              }
 279          }
 280          return $siblings;
 281      }
 282  
 283      /**
 284       * This sets the URL that the URL of new nodes get compared to when locating
 285       * the active node.
 286       *
 287       * The active node is the node that matches the URL set here. By default this
 288       * is either $PAGE->url or if that hasn't been set $FULLME.
 289       *
 290       * @param moodle_url $url The url to use for the fullmeurl.
 291       * @param bool $loadadmintree use true if the URL point to administration tree
 292       */
 293      public static function override_active_url(moodle_url $url, $loadadmintree = false) {
 294          // Clone the URL, in case the calling script changes their URL later.
 295          self::$fullmeurl = new moodle_url($url);
 296          // True means we do not want AJAX loaded admin tree, required for all admin pages.
 297          if ($loadadmintree) {
 298              // Do not change back to false if already set.
 299              self::$loadadmintree = true;
 300          }
 301      }
 302  
 303      /**
 304       * Use when page is linked from the admin tree,
 305       * if not used navigation could not find the page using current URL
 306       * because the tree is not fully loaded.
 307       */
 308      public static function require_admin_tree() {
 309          self::$loadadmintree = true;
 310      }
 311  
 312      /**
 313       * Creates a navigation node, ready to add it as a child using add_node
 314       * function. (The created node needs to be added before you can use it.)
 315       * @param string $text
 316       * @param moodle_url|action_link $action
 317       * @param int $type
 318       * @param string $shorttext
 319       * @param string|int $key
 320       * @param pix_icon $icon
 321       * @return navigation_node
 322       */
 323      public static function create($text, $action=null, $type=self::TYPE_CUSTOM,
 324              $shorttext=null, $key=null, pix_icon $icon=null) {
 325          // Properties array used when creating the new navigation node
 326          $itemarray = array(
 327              'text' => $text,
 328              'type' => $type
 329          );
 330          // Set the action if one was provided
 331          if ($action!==null) {
 332              $itemarray['action'] = $action;
 333          }
 334          // Set the shorttext if one was provided
 335          if ($shorttext!==null) {
 336              $itemarray['shorttext'] = $shorttext;
 337          }
 338          // Set the icon if one was provided
 339          if ($icon!==null) {
 340              $itemarray['icon'] = $icon;
 341          }
 342          // Set the key
 343          $itemarray['key'] = $key;
 344          // Construct and return
 345          return new navigation_node($itemarray);
 346      }
 347  
 348      /**
 349       * Adds a navigation node as a child of this node.
 350       *
 351       * @param string $text
 352       * @param moodle_url|action_link $action
 353       * @param int $type
 354       * @param string $shorttext
 355       * @param string|int $key
 356       * @param pix_icon $icon
 357       * @return navigation_node
 358       */
 359      public function add($text, $action=null, $type=self::TYPE_CUSTOM, $shorttext=null, $key=null, pix_icon $icon=null) {
 360          // Create child node
 361          $childnode = self::create($text, $action, $type, $shorttext, $key, $icon);
 362  
 363          // Add the child to end and return
 364          return $this->add_node($childnode);
 365      }
 366  
 367      /**
 368       * Adds a navigation node as a child of this one, given a $node object
 369       * created using the create function.
 370       * @param navigation_node $childnode Node to add
 371       * @param string $beforekey
 372       * @return navigation_node The added node
 373       */
 374      public function add_node(navigation_node $childnode, $beforekey=null) {
 375          // First convert the nodetype for this node to a branch as it will now have children
 376          if ($this->nodetype !== self::NODETYPE_BRANCH) {
 377              $this->nodetype = self::NODETYPE_BRANCH;
 378          }
 379          // Set the parent to this node
 380          $childnode->set_parent($this);
 381  
 382          // Default the key to the number of children if not provided
 383          if ($childnode->key === null) {
 384              $childnode->key = $this->children->count();
 385          }
 386  
 387          // Add the child using the navigation_node_collections add method
 388          $node = $this->children->add($childnode, $beforekey);
 389  
 390          // If added node is a category node or the user is logged in and it's a course
 391          // then mark added node as a branch (makes it expandable by AJAX)
 392          $type = $childnode->type;
 393          if (($type == self::TYPE_CATEGORY) || (isloggedin() && ($type == self::TYPE_COURSE)) || ($type == self::TYPE_MY_CATEGORY) ||
 394                  ($type === self::TYPE_SITE_ADMIN)) {
 395              $node->nodetype = self::NODETYPE_BRANCH;
 396          }
 397          // If this node is hidden mark it's children as hidden also
 398          if ($this->hidden) {
 399              $node->hidden = true;
 400          }
 401          // Return added node (reference returned by $this->children->add()
 402          return $node;
 403      }
 404  
 405      /**
 406       * Return a list of all the keys of all the child nodes.
 407       * @return array the keys.
 408       */
 409      public function get_children_key_list() {
 410          return $this->children->get_key_list();
 411      }
 412  
 413      /**
 414       * Searches for a node of the given type with the given key.
 415       *
 416       * This searches this node plus all of its children, and their children....
 417       * If you know the node you are looking for is a child of this node then please
 418       * use the get method instead.
 419       *
 420       * @param int|string $key The key of the node we are looking for
 421       * @param int $type One of navigation_node::TYPE_*
 422       * @return navigation_node|false
 423       */
 424      public function find($key, $type) {
 425          return $this->children->find($key, $type);
 426      }
 427  
 428      /**
 429       * Walk the tree building up a list of all the flat navigation nodes.
 430       *
 431       * @param flat_navigation $nodes List of the found flat navigation nodes.
 432       * @param boolean $showdivider Show a divider before the first node.
 433       * @param string $label A label for the collection of navigation links.
 434       */
 435      public function build_flat_navigation_list(flat_navigation $nodes, $showdivider = false, $label = '') {
 436          if ($this->showinflatnavigation) {
 437              $indent = 0;
 438              if ($this->type == self::TYPE_COURSE || $this->key === self::COURSE_INDEX_PAGE) {
 439                  $indent = 1;
 440              }
 441              $flat = new flat_navigation_node($this, $indent);
 442              $flat->set_showdivider($showdivider, $label);
 443              $nodes->add($flat);
 444          }
 445          foreach ($this->children as $child) {
 446              $child->build_flat_navigation_list($nodes, false);
 447          }
 448      }
 449  
 450      /**
 451       * Get the child of this node that has the given key + (optional) type.
 452       *
 453       * If you are looking for a node and want to search all children + their children
 454       * then please use the find method instead.
 455       *
 456       * @param int|string $key The key of the node we are looking for
 457       * @param int $type One of navigation_node::TYPE_*
 458       * @return navigation_node|false
 459       */
 460      public function get($key, $type=null) {
 461          return $this->children->get($key, $type);
 462      }
 463  
 464      /**
 465       * Removes this node.
 466       *
 467       * @return bool
 468       */
 469      public function remove() {
 470          return $this->parent->children->remove($this->key, $this->type);
 471      }
 472  
 473      /**
 474       * Checks if this node has or could have any children
 475       *
 476       * @return bool Returns true if it has children or could have (by AJAX expansion)
 477       */
 478      public function has_children() {
 479          return ($this->nodetype === navigation_node::NODETYPE_BRANCH || $this->children->count()>0 || $this->isexpandable);
 480      }
 481  
 482      /**
 483       * Marks this node as active and forces it open.
 484       *
 485       * Important: If you are here because you need to mark a node active to get
 486       * the navigation to do what you want have you looked at {@link navigation_node::override_active_url()}?
 487       * You can use it to specify a different URL to match the active navigation node on
 488       * rather than having to locate and manually mark a node active.
 489       */
 490      public function make_active() {
 491          $this->isactive = true;
 492          $this->add_class('active_tree_node');
 493          $this->force_open();
 494          if ($this->parent !== null) {
 495              $this->parent->make_inactive();
 496          }
 497      }
 498  
 499      /**
 500       * Marks a node as inactive and recusised back to the base of the tree
 501       * doing the same to all parents.
 502       */
 503      public function make_inactive() {
 504          $this->isactive = false;
 505          $this->remove_class('active_tree_node');
 506          if ($this->parent !== null) {
 507              $this->parent->make_inactive();
 508          }
 509      }
 510  
 511      /**
 512       * Forces this node to be open and at the same time forces open all
 513       * parents until the root node.
 514       *
 515       * Recursive.
 516       */
 517      public function force_open() {
 518          $this->forceopen = true;
 519          if ($this->parent !== null) {
 520              $this->parent->force_open();
 521          }
 522      }
 523  
 524      /**
 525       * Adds a CSS class to this node.
 526       *
 527       * @param string $class
 528       * @return bool
 529       */
 530      public function add_class($class) {
 531          if (!in_array($class, $this->classes)) {
 532              $this->classes[] = $class;
 533          }
 534          return true;
 535      }
 536  
 537      /**
 538       * Removes a CSS class from this node.
 539       *
 540       * @param string $class
 541       * @return bool True if the class was successfully removed.
 542       */
 543      public function remove_class($class) {
 544          if (in_array($class, $this->classes)) {
 545              $key = array_search($class,$this->classes);
 546              if ($key!==false) {
 547                  // Remove the class' array element.
 548                  unset($this->classes[$key]);
 549                  // Reindex the array to avoid failures when the classes array is iterated later in mustache templates.
 550                  $this->classes = array_values($this->classes);
 551  
 552                  return true;
 553              }
 554          }
 555          return false;
 556      }
 557  
 558      /**
 559       * Sets the title for this node and forces Moodle to utilise it.
 560       * @param string $title
 561       */
 562      public function title($title) {
 563          $this->title = $title;
 564          $this->forcetitle = true;
 565      }
 566  
 567      /**
 568       * Resets the page specific information on this node if it is being unserialised.
 569       */
 570      public function __wakeup(){
 571          $this->forceopen = false;
 572          $this->isactive = false;
 573          $this->remove_class('active_tree_node');
 574      }
 575  
 576      /**
 577       * Checks if this node or any of its children contain the active node.
 578       *
 579       * Recursive.
 580       *
 581       * @return bool
 582       */
 583      public function contains_active_node() {
 584          if ($this->isactive) {
 585              return true;
 586          } else {
 587              foreach ($this->children as $child) {
 588                  if ($child->isactive || $child->contains_active_node()) {
 589                      return true;
 590                  }
 591              }
 592          }
 593          return false;
 594      }
 595  
 596      /**
 597       * To better balance the admin tree, we want to group all the short top branches together.
 598       *
 599       * This means < 8 nodes and no subtrees.
 600       *
 601       * @return bool
 602       */
 603      public function is_short_branch() {
 604          $limit = 8;
 605          if ($this->children->count() >= $limit) {
 606              return false;
 607          }
 608          foreach ($this->children as $child) {
 609              if ($child->has_children()) {
 610                  return false;
 611              }
 612          }
 613          return true;
 614      }
 615  
 616      /**
 617       * Finds the active node.
 618       *
 619       * Searches this nodes children plus all of the children for the active node
 620       * and returns it if found.
 621       *
 622       * Recursive.
 623       *
 624       * @return navigation_node|false
 625       */
 626      public function find_active_node() {
 627          if ($this->isactive) {
 628              return $this;
 629          } else {
 630              foreach ($this->children as &$child) {
 631                  $outcome = $child->find_active_node();
 632                  if ($outcome !== false) {
 633                      return $outcome;
 634                  }
 635              }
 636          }
 637          return false;
 638      }
 639  
 640      /**
 641       * Searches all children for the best matching active node
 642       * @return navigation_node|false
 643       */
 644      public function search_for_active_node() {
 645          if ($this->check_if_active(URL_MATCH_BASE)) {
 646              return $this;
 647          } else {
 648              foreach ($this->children as &$child) {
 649                  $outcome = $child->search_for_active_node();
 650                  if ($outcome !== false) {
 651                      return $outcome;
 652                  }
 653              }
 654          }
 655          return false;
 656      }
 657  
 658      /**
 659       * Gets the content for this node.
 660       *
 661       * @param bool $shorttext If true shorttext is used rather than the normal text
 662       * @return string
 663       */
 664      public function get_content($shorttext=false) {
 665          $navcontext = \context_helper::get_navigation_filter_context(null);
 666          $options = !empty($navcontext) ? ['context' => $navcontext] : null;
 667  
 668          if ($shorttext && $this->shorttext!==null) {
 669              return format_string($this->shorttext, null, $options);
 670          } else {
 671              return format_string($this->text, null, $options);
 672          }
 673      }
 674  
 675      /**
 676       * Gets the title to use for this node.
 677       *
 678       * @return string
 679       */
 680      public function get_title() {
 681          if ($this->forcetitle || $this->action != null){
 682              return $this->title;
 683          } else {
 684              return '';
 685          }
 686      }
 687  
 688      /**
 689       * Used to easily determine if this link in the breadcrumbs has a valid action/url.
 690       *
 691       * @return boolean
 692       */
 693      public function has_action() {
 694          return !empty($this->action);
 695      }
 696  
 697      /**
 698       * Used to easily determine if this link in the breadcrumbs is hidden.
 699       *
 700       * @return boolean
 701       */
 702      public function is_hidden() {
 703          return $this->hidden;
 704      }
 705  
 706      /**
 707       * Gets the CSS class to add to this node to describe its type
 708       *
 709       * @return string
 710       */
 711      public function get_css_type() {
 712          if (array_key_exists($this->type, $this->namedtypes)) {
 713              return 'type_'.$this->namedtypes[$this->type];
 714          }
 715          return 'type_unknown';
 716      }
 717  
 718      /**
 719       * Finds all nodes that are expandable by AJAX
 720       *
 721       * @param array $expandable An array by reference to populate with expandable nodes.
 722       */
 723      public function find_expandable(array &$expandable) {
 724          foreach ($this->children as &$child) {
 725              if ($child->display && $child->has_children() && $child->children->count() == 0) {
 726                  $child->id = 'expandable_branch_'.$child->type.'_'.clean_param($child->key, PARAM_ALPHANUMEXT);
 727                  $this->add_class('canexpand');
 728                  $child->requiresajaxloading = true;
 729                  $expandable[] = array('id' => $child->id, 'key' => $child->key, 'type' => $child->type);
 730              }
 731              $child->find_expandable($expandable);
 732          }
 733      }
 734  
 735      /**
 736       * Finds all nodes of a given type (recursive)
 737       *
 738       * @param int $type One of navigation_node::TYPE_*
 739       * @return array
 740       */
 741      public function find_all_of_type($type) {
 742          $nodes = $this->children->type($type);
 743          foreach ($this->children as &$node) {
 744              $childnodes = $node->find_all_of_type($type);
 745              $nodes = array_merge($nodes, $childnodes);
 746          }
 747          return $nodes;
 748      }
 749  
 750      /**
 751       * Removes this node if it is empty
 752       */
 753      public function trim_if_empty() {
 754          if ($this->children->count() == 0) {
 755              $this->remove();
 756          }
 757      }
 758  
 759      /**
 760       * Creates a tab representation of this nodes children that can be used
 761       * with print_tabs to produce the tabs on a page.
 762       *
 763       * call_user_func_array('print_tabs', $node->get_tabs_array());
 764       *
 765       * @param array $inactive
 766       * @param bool $return
 767       * @return array Array (tabs, selected, inactive, activated, return)
 768       */
 769      public function get_tabs_array(array $inactive=array(), $return=false) {
 770          $tabs = array();
 771          $rows = array();
 772          $selected = null;
 773          $activated = array();
 774          foreach ($this->children as $node) {
 775              $tabs[] = new tabobject($node->key, $node->action, $node->get_content(), $node->get_title());
 776              if ($node->contains_active_node()) {
 777                  if ($node->children->count() > 0) {
 778                      $activated[] = $node->key;
 779                      foreach ($node->children as $child) {
 780                          if ($child->contains_active_node()) {
 781                              $selected = $child->key;
 782                          }
 783                          $rows[] = new tabobject($child->key, $child->action, $child->get_content(), $child->get_title());
 784                      }
 785                  } else {
 786                      $selected = $node->key;
 787                  }
 788              }
 789          }
 790          return array(array($tabs, $rows), $selected, $inactive, $activated, $return);
 791      }
 792  
 793      /**
 794       * Sets the parent for this node and if this node is active ensures that the tree is properly
 795       * adjusted as well.
 796       *
 797       * @param navigation_node $parent
 798       */
 799      public function set_parent(navigation_node $parent) {
 800          // Set the parent (thats the easy part)
 801          $this->parent = $parent;
 802          // Check if this node is active (this is checked during construction)
 803          if ($this->isactive) {
 804              // Force all of the parent nodes open so you can see this node
 805              $this->parent->force_open();
 806              // Make all parents inactive so that its clear where we are.
 807              $this->parent->make_inactive();
 808          }
 809      }
 810  
 811      /**
 812       * Hides the node and any children it has.
 813       *
 814       * @since Moodle 2.5
 815       * @param array $typestohide Optional. An array of node types that should be hidden.
 816       *      If null all nodes will be hidden.
 817       *      If an array is given then nodes will only be hidden if their type mtatches an element in the array.
 818       *          e.g. array(navigation_node::TYPE_COURSE) would hide only course nodes.
 819       */
 820      public function hide(array $typestohide = null) {
 821          if ($typestohide === null || in_array($this->type, $typestohide)) {
 822              $this->display = false;
 823              if ($this->has_children()) {
 824                  foreach ($this->children as $child) {
 825                      $child->hide($typestohide);
 826                  }
 827              }
 828          }
 829      }
 830  
 831      /**
 832       * Get the action url for this navigation node.
 833       * Called from templates.
 834       *
 835       * @since Moodle 3.2
 836       */
 837      public function action() {
 838          if ($this->action instanceof moodle_url) {
 839              return $this->action;
 840          } else if ($this->action instanceof action_link) {
 841              return $this->action->url;
 842          }
 843          return $this->action;
 844      }
 845  
 846      /**
 847       * Add the menu item to handle locking and unlocking of a conext.
 848       *
 849       * @param \navigation_node $node Node to add
 850       * @param \context $context The context to be locked
 851       */
 852      protected function add_context_locking_node(\navigation_node $node, \context $context) {
 853          global $CFG;
 854          // Manage context locking.
 855          if (!empty($CFG->contextlocking) && has_capability('moodle/site:managecontextlocks', $context)) {
 856              $parentcontext = $context->get_parent_context();
 857              if (empty($parentcontext) || !$parentcontext->locked) {
 858                  if ($context->locked) {
 859                      $lockicon = 'i/unlock';
 860                      $lockstring = get_string('managecontextunlock', 'admin');
 861                  } else {
 862                      $lockicon = 'i/lock';
 863                      $lockstring = get_string('managecontextlock', 'admin');
 864                  }
 865                  $node->add(
 866                      $lockstring,
 867                      new moodle_url(
 868                          '/admin/lock.php',
 869                          [
 870                              'id' => $context->id,
 871                          ]
 872                      ),
 873                      self::TYPE_SETTING,
 874                      null,
 875                      'contextlocking',
 876                       new pix_icon($lockicon, '')
 877                  );
 878              }
 879          }
 880  
 881      }
 882  }
 883  
 884  /**
 885   * Navigation node collection
 886   *
 887   * This class is responsible for managing a collection of navigation nodes.
 888   * It is required because a node's unique identifier is a combination of both its
 889   * key and its type.
 890   *
 891   * Originally an array was used with a string key that was a combination of the two
 892   * however it was decided that a better solution would be to use a class that
 893   * implements the standard IteratorAggregate interface.
 894   *
 895   * @package   core
 896   * @category  navigation
 897   * @copyright 2010 Sam Hemelryk
 898   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 899   */
 900  class navigation_node_collection implements IteratorAggregate, Countable {
 901      /**
 902       * A multidimensional array to where the first key is the type and the second
 903       * key is the nodes key.
 904       * @var array
 905       */
 906      protected $collection = array();
 907      /**
 908       * An array that contains references to nodes in the same order they were added.
 909       * This is maintained as a progressive array.
 910       * @var array
 911       */
 912      protected $orderedcollection = array();
 913      /**
 914       * A reference to the last node that was added to the collection
 915       * @var navigation_node
 916       */
 917      protected $last = null;
 918      /**
 919       * The total number of items added to this array.
 920       * @var int
 921       */
 922      protected $count = 0;
 923  
 924      /**
 925       * Label for collection of nodes.
 926       * @var string
 927       */
 928      protected $collectionlabel = '';
 929  
 930      /**
 931       * Adds a navigation node to the collection
 932       *
 933       * @param navigation_node $node Node to add
 934       * @param string $beforekey If specified, adds before a node with this key,
 935       *   otherwise adds at end
 936       * @return navigation_node Added node
 937       */
 938      public function add(navigation_node $node, $beforekey=null) {
 939          global $CFG;
 940          $key = $node->key;
 941          $type = $node->type;
 942  
 943          // First check we have a 2nd dimension for this type
 944          if (!array_key_exists($type, $this->orderedcollection)) {
 945              $this->orderedcollection[$type] = array();
 946          }
 947          // Check for a collision and report if debugging is turned on
 948          if ($CFG->debug && array_key_exists($key, $this->orderedcollection[$type])) {
 949              debugging('Navigation node intersect: Adding a node that already exists '.$key, DEBUG_DEVELOPER);
 950          }
 951  
 952          // Find the key to add before
 953          $newindex = $this->count;
 954          $last = true;
 955          if ($beforekey !== null) {
 956              foreach ($this->collection as $index => $othernode) {
 957                  if ($othernode->key === $beforekey) {
 958                      $newindex = $index;
 959                      $last = false;
 960                      break;
 961                  }
 962              }
 963              if ($newindex === $this->count) {
 964                  debugging('Navigation node add_before: Reference node not found ' . $beforekey .
 965                          ', options: ' . implode(' ', $this->get_key_list()), DEBUG_DEVELOPER);
 966              }
 967          }
 968  
 969          // Add the node to the appropriate place in the by-type structure (which
 970          // is not ordered, despite the variable name)
 971          $this->orderedcollection[$type][$key] = $node;
 972          if (!$last) {
 973              // Update existing references in the ordered collection (which is the
 974              // one that isn't called 'ordered') to shuffle them along if required
 975              for ($oldindex = $this->count; $oldindex > $newindex; $oldindex--) {
 976                  $this->collection[$oldindex] = $this->collection[$oldindex - 1];
 977              }
 978          }
 979          // Add a reference to the node to the progressive collection.
 980          $this->collection[$newindex] = $this->orderedcollection[$type][$key];
 981          // Update the last property to a reference to this new node.
 982          $this->last = $this->orderedcollection[$type][$key];
 983  
 984          // Reorder the array by index if needed
 985          if (!$last) {
 986              ksort($this->collection);
 987          }
 988          $this->count++;
 989          // Return the reference to the now added node
 990          return $node;
 991      }
 992  
 993      /**
 994       * Return a list of all the keys of all the nodes.
 995       * @return array the keys.
 996       */
 997      public function get_key_list() {
 998          $keys = array();
 999          foreach ($this->collection as $node) {
1000              $keys[] = $node->key;
1001          }
1002          return $keys;
1003      }
1004  
1005      /**
1006       * Set a label for this collection.
1007       *
1008       * @param string $label
1009       */
1010      public function set_collectionlabel($label) {
1011          $this->collectionlabel = $label;
1012      }
1013  
1014      /**
1015       * Return a label for this collection.
1016       *
1017       * @return string
1018       */
1019      public function get_collectionlabel() {
1020          return $this->collectionlabel;
1021      }
1022  
1023      /**
1024       * Fetches a node from this collection.
1025       *
1026       * @param string|int $key The key of the node we want to find.
1027       * @param int $type One of navigation_node::TYPE_*.
1028       * @return navigation_node|null
1029       */
1030      public function get($key, $type=null) {
1031          if ($type !== null) {
1032              // If the type is known then we can simply check and fetch
1033              if (!empty($this->orderedcollection[$type][$key])) {
1034                  return $this->orderedcollection[$type][$key];
1035              }
1036          } else {
1037              // Because we don't know the type we look in the progressive array
1038              foreach ($this->collection as $node) {
1039                  if ($node->key === $key) {
1040                      return $node;
1041                  }
1042              }
1043          }
1044          return false;
1045      }
1046  
1047      /**
1048       * Searches for a node with matching key and type.
1049       *
1050       * This function searches both the nodes in this collection and all of
1051       * the nodes in each collection belonging to the nodes in this collection.
1052       *
1053       * Recursive.
1054       *
1055       * @param string|int $key  The key of the node we want to find.
1056       * @param int $type  One of navigation_node::TYPE_*.
1057       * @return navigation_node|null
1058       */
1059      public function find($key, $type=null) {
1060          if ($type !== null && array_key_exists($type, $this->orderedcollection) && array_key_exists($key, $this->orderedcollection[$type])) {
1061              return $this->orderedcollection[$type][$key];
1062          } else {
1063              $nodes = $this->getIterator();
1064              // Search immediate children first
1065              foreach ($nodes as &$node) {
1066                  if ($node->key === $key && ($type === null || $type === $node->type)) {
1067                      return $node;
1068                  }
1069              }
1070              // Now search each childs children
1071              foreach ($nodes as &$node) {
1072                  $result = $node->children->find($key, $type);
1073                  if ($result !== false) {
1074                      return $result;
1075                  }
1076              }
1077          }
1078          return false;
1079      }
1080  
1081      /**
1082       * Fetches the last node that was added to this collection
1083       *
1084       * @return navigation_node
1085       */
1086      public function last() {
1087          return $this->last;
1088      }
1089  
1090      /**
1091       * Fetches all nodes of a given type from this collection
1092       *
1093       * @param string|int $type  node type being searched for.
1094       * @return array ordered collection
1095       */
1096      public function type($type) {
1097          if (!array_key_exists($type, $this->orderedcollection)) {
1098              $this->orderedcollection[$type] = array();
1099          }
1100          return $this->orderedcollection[$type];
1101      }
1102      /**
1103       * Removes the node with the given key and type from the collection
1104       *
1105       * @param string|int $key The key of the node we want to find.
1106       * @param int $type
1107       * @return bool
1108       */
1109      public function remove($key, $type=null) {
1110          $child = $this->get($key, $type);
1111          if ($child !== false) {
1112              foreach ($this->collection as $colkey => $node) {
1113                  if ($node->key === $key && (is_null($type) || $node->type == $type)) {
1114                      unset($this->collection[$colkey]);
1115                      $this->collection = array_values($this->collection);
1116                      break;
1117                  }
1118              }
1119              unset($this->orderedcollection[$child->type][$child->key]);
1120              $this->count--;
1121              return true;
1122          }
1123          return false;
1124      }
1125  
1126      /**
1127       * Gets the number of nodes in this collection
1128       *
1129       * This option uses an internal count rather than counting the actual options to avoid
1130       * a performance hit through the count function.
1131       *
1132       * @return int
1133       */
1134      public function count() {
1135          return $this->count;
1136      }
1137      /**
1138       * Gets an array iterator for the collection.
1139       *
1140       * This is required by the IteratorAggregator interface and is used by routines
1141       * such as the foreach loop.
1142       *
1143       * @return ArrayIterator
1144       */
1145      public function getIterator() {
1146          return new ArrayIterator($this->collection);
1147      }
1148  }
1149  
1150  /**
1151   * The global navigation class used for... the global navigation
1152   *
1153   * This class is used by PAGE to store the global navigation for the site
1154   * and is then used by the settings nav and navbar to save on processing and DB calls
1155   *
1156   * See
1157   * {@link lib/pagelib.php} {@link moodle_page::initialise_theme_and_output()}
1158   * {@link lib/ajax/getnavbranch.php} Called by ajax
1159   *
1160   * @package   core
1161   * @category  navigation
1162   * @copyright 2009 Sam Hemelryk
1163   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1164   */
1165  class global_navigation extends navigation_node {
1166      /** @var moodle_page The Moodle page this navigation object belongs to. */
1167      protected $page;
1168      /** @var bool switch to let us know if the navigation object is initialised*/
1169      protected $initialised = false;
1170      /** @var array An array of course information */
1171      protected $mycourses = array();
1172      /** @var navigation_node[] An array for containing  root navigation nodes */
1173      protected $rootnodes = array();
1174      /** @var bool A switch for whether to show empty sections in the navigation */
1175      protected $showemptysections = true;
1176      /** @var bool A switch for whether courses should be shown within categories on the navigation. */
1177      protected $showcategories = null;
1178      /** @var null@var bool A switch for whether or not to show categories in the my courses branch. */
1179      protected $showmycategories = null;
1180      /** @var array An array of stdClasses for users that the navigation is extended for */
1181      protected $extendforuser = array();
1182      /** @var navigation_cache */
1183      protected $cache;
1184      /** @var array An array of course ids that are present in the navigation */
1185      protected $addedcourses = array();
1186      /** @var bool */
1187      protected $allcategoriesloaded = false;
1188      /** @var array An array of category ids that are included in the navigation */
1189      protected $addedcategories = array();
1190      /** @var int expansion limit */
1191      protected $expansionlimit = 0;
1192      /** @var int userid to allow parent to see child's profile page navigation */
1193      protected $useridtouseforparentchecks = 0;
1194      /** @var cache_session A cache that stores information on expanded courses */
1195      protected $cacheexpandcourse = null;
1196  
1197      /** Used when loading categories to load all top level categories [parent = 0] **/
1198      const LOAD_ROOT_CATEGORIES = 0;
1199      /** Used when loading categories to load all categories **/
1200      const LOAD_ALL_CATEGORIES = -1;
1201  
1202      /**
1203       * Constructs a new global navigation
1204       *
1205       * @param moodle_page $page The page this navigation object belongs to
1206       */
1207      public function __construct(moodle_page $page) {
1208          global $CFG, $SITE, $USER;
1209  
1210          if (during_initial_install()) {
1211              return;
1212          }
1213  
1214          if (get_home_page() == HOMEPAGE_SITE) {
1215              // We are using the site home for the root element
1216              $properties = array(
1217                  'key' => 'home',
1218                  'type' => navigation_node::TYPE_SYSTEM,
1219                  'text' => get_string('home'),
1220                  'action' => new moodle_url('/'),
1221                  'icon' => new pix_icon('i/home', '')
1222              );
1223          } else {
1224              // We are using the users my moodle for the root element
1225              $properties = array(
1226                  'key' => 'myhome',
1227                  'type' => navigation_node::TYPE_SYSTEM,
1228                  'text' => get_string('myhome'),
1229                  'action' => new moodle_url('/my/'),
1230                  'icon' => new pix_icon('i/dashboard', '')
1231              );
1232          }
1233  
1234          // Use the parents constructor.... good good reuse
1235          parent::__construct($properties);
1236          $this->showinflatnavigation = true;
1237  
1238          // Initalise and set defaults
1239          $this->page = $page;
1240          $this->forceopen = true;
1241          $this->cache = new navigation_cache(NAVIGATION_CACHE_NAME);
1242      }
1243  
1244      /**
1245       * Mutator to set userid to allow parent to see child's profile
1246       * page navigation. See MDL-25805 for initial issue. Linked to it
1247       * is an issue explaining why this is a REALLY UGLY HACK thats not
1248       * for you to use!
1249       *
1250       * @param int $userid userid of profile page that parent wants to navigate around.
1251       */
1252      public function set_userid_for_parent_checks($userid) {
1253          $this->useridtouseforparentchecks = $userid;
1254      }
1255  
1256  
1257      /**
1258       * Initialises the navigation object.
1259       *
1260       * This causes the navigation object to look at the current state of the page
1261       * that it is associated with and then load the appropriate content.
1262       *
1263       * This should only occur the first time that the navigation structure is utilised
1264       * which will normally be either when the navbar is called to be displayed or
1265       * when a block makes use of it.
1266       *
1267       * @return bool
1268       */
1269      public function initialise() {
1270          global $CFG, $SITE, $USER;
1271          // Check if it has already been initialised
1272          if ($this->initialised || during_initial_install()) {
1273              return true;
1274          }
1275          $this->initialised = true;
1276  
1277          // Set up the five base root nodes. These are nodes where we will put our
1278          // content and are as follows:
1279          // site: Navigation for the front page.
1280          // myprofile: User profile information goes here.
1281          // currentcourse: The course being currently viewed.
1282          // mycourses: The users courses get added here.
1283          // courses: Additional courses are added here.
1284          // users: Other users information loaded here.
1285          $this->rootnodes = array();
1286          if (get_home_page() == HOMEPAGE_SITE) {
1287              // The home element should be my moodle because the root element is the site
1288              if (isloggedin() && !isguestuser()) {  // Makes no sense if you aren't logged in
1289                  $this->rootnodes['home'] = $this->add(get_string('myhome'), new moodle_url('/my/'),
1290                      self::TYPE_SETTING, null, 'myhome', new pix_icon('i/dashboard', ''));
1291                  $this->rootnodes['home']->showinflatnavigation = true;
1292              }
1293          } else {
1294              // The home element should be the site because the root node is my moodle
1295              $this->rootnodes['home'] = $this->add(get_string('sitehome'), new moodle_url('/'),
1296                  self::TYPE_SETTING, null, 'home', new pix_icon('i/home', ''));
1297              $this->rootnodes['home']->showinflatnavigation = true;
1298              if (!empty($CFG->defaulthomepage) && ($CFG->defaulthomepage == HOMEPAGE_MY)) {
1299                  // We need to stop automatic redirection
1300                  $this->rootnodes['home']->action->param('redirect', '0');
1301              }
1302          }
1303          $this->rootnodes['site'] = $this->add_course($SITE);
1304          $this->rootnodes['myprofile'] = $this->add(get_string('profile'), null, self::TYPE_USER, null, 'myprofile');
1305          $this->rootnodes['currentcourse'] = $this->add(get_string('currentcourse'), null, self::TYPE_ROOTNODE, null, 'currentcourse');
1306          $this->rootnodes['mycourses'] = $this->add(get_string('mycourses'), null, self::TYPE_ROOTNODE, null, 'mycourses', new pix_icon('i/course', ''));
1307          $this->rootnodes['courses'] = $this->add(get_string('courses'), new moodle_url('/course/index.php'), self::TYPE_ROOTNODE, null, 'courses');
1308          if (!core_course_category::user_top()) {
1309              $this->rootnodes['courses']->hide();
1310          }
1311          $this->rootnodes['users'] = $this->add(get_string('users'), null, self::TYPE_ROOTNODE, null, 'users');
1312  
1313          // We always load the frontpage course to ensure it is available without
1314          // JavaScript enabled.
1315          $this->add_front_page_course_essentials($this->rootnodes['site'], $SITE);
1316          $this->load_course_sections($SITE, $this->rootnodes['site']);
1317  
1318          $course = $this->page->course;
1319          $this->load_courses_enrolled();
1320  
1321          // $issite gets set to true if the current pages course is the sites frontpage course
1322          $issite = ($this->page->course->id == $SITE->id);
1323  
1324          // Determine if the user is enrolled in any course.
1325          $enrolledinanycourse = enrol_user_sees_own_courses();
1326  
1327          $this->rootnodes['currentcourse']->mainnavonly = true;
1328          if ($enrolledinanycourse) {
1329              $this->rootnodes['mycourses']->isexpandable = true;
1330              $this->rootnodes['mycourses']->showinflatnavigation = true;
1331              if ($CFG->navshowallcourses) {
1332                  // When we show all courses we need to show both the my courses and the regular courses branch.
1333                  $this->rootnodes['courses']->isexpandable = true;
1334              }
1335          } else {
1336              $this->rootnodes['courses']->isexpandable = true;
1337          }
1338          $this->rootnodes['mycourses']->forceopen = true;
1339  
1340          $canviewcourseprofile = true;
1341  
1342          // Next load context specific content into the navigation
1343          switch ($this->page->context->contextlevel) {
1344              case CONTEXT_SYSTEM :
1345                  // Nothing left to do here I feel.
1346                  break;
1347              case CONTEXT_COURSECAT :
1348                  // This is essential, we must load categories.
1349                  $this->load_all_categories($this->page->context->instanceid, true);
1350                  break;
1351              case CONTEXT_BLOCK :
1352              case CONTEXT_COURSE :
1353                  if ($issite) {
1354                      // Nothing left to do here.
1355                      break;
1356                  }
1357  
1358                  // Load the course associated with the current page into the navigation.
1359                  $coursenode = $this->add_course($course, false, self::COURSE_CURRENT);
1360                  // If the course wasn't added then don't try going any further.
1361                  if (!$coursenode) {
1362                      $canviewcourseprofile = false;
1363                      break;
1364                  }
1365  
1366                  // If the user is not enrolled then we only want to show the
1367                  // course node and not populate it.
1368  
1369                  // Not enrolled, can't view, and hasn't switched roles
1370                  if (!can_access_course($course, null, '', true)) {
1371                      if ($coursenode->isexpandable === true) {
1372                          // Obviously the situation has changed, update the cache and adjust the node.
1373                          // This occurs if the user access to a course has been revoked (one way or another) after
1374                          // initially logging in for this session.
1375                          $this->get_expand_course_cache()->set($course->id, 1);
1376                          $coursenode->isexpandable = true;
1377                          $coursenode->nodetype = self::NODETYPE_BRANCH;
1378                      }
1379                      // Very ugly hack - do not force "parents" to enrol into course their child is enrolled in,
1380                      // this hack has been propagated from user/view.php to display the navigation node. (MDL-25805)
1381                      if (!$this->current_user_is_parent_role()) {
1382                          $coursenode->make_active();
1383                          $canviewcourseprofile = false;
1384                          break;
1385                      }
1386                  } else if ($coursenode->isexpandable === false) {
1387                      // Obviously the situation has changed, update the cache and adjust the node.
1388                      // This occurs if the user has been granted access to a course (one way or another) after initially
1389                      // logging in for this session.
1390                      $this->get_expand_course_cache()->set($course->id, 1);
1391                      $coursenode->isexpandable = true;
1392                      $coursenode->nodetype = self::NODETYPE_BRANCH;
1393                  }
1394  
1395                  // Add the essentials such as reports etc...
1396                  $this->add_course_essentials($coursenode, $course);
1397                  // Extend course navigation with it's sections/activities
1398                  $this->load_course_sections($course, $coursenode);
1399                  if (!$coursenode->contains_active_node() && !$coursenode->search_for_active_node()) {
1400                      $coursenode->make_active();
1401                  }
1402  
1403                  break;
1404              case CONTEXT_MODULE :
1405                  if ($issite) {
1406                      // If this is the site course then most information will have
1407                      // already been loaded.
1408                      // However we need to check if there is more content that can
1409                      // yet be loaded for the specific module instance.
1410                      $activitynode = $this->rootnodes['site']->find($this->page->cm->id, navigation_node::TYPE_ACTIVITY);
1411                      if ($activitynode) {
1412                          $this->load_activity($this->page->cm, $this->page->course, $activitynode);
1413                      }
1414                      break;
1415                  }
1416  
1417                  $course = $this->page->course;
1418                  $cm = $this->page->cm;
1419  
1420                  // Load the course associated with the page into the navigation
1421                  $coursenode = $this->add_course($course, false, self::COURSE_CURRENT);
1422  
1423                  // If the course wasn't added then don't try going any further.
1424                  if (!$coursenode) {
1425                      $canviewcourseprofile = false;
1426                      break;
1427                  }
1428  
1429                  // If the user is not enrolled then we only want to show the
1430                  // course node and not populate it.
1431                  if (!can_access_course($course, null, '', true)) {
1432                      $coursenode->make_active();
1433                      $canviewcourseprofile = false;
1434                      break;
1435                  }
1436  
1437                  $this->add_course_essentials($coursenode, $course);
1438  
1439                  // Load the course sections into the page
1440                  $this->load_course_sections($course, $coursenode, null, $cm);
1441                  $activity = $coursenode->find($cm->id, navigation_node::TYPE_ACTIVITY);
1442                  if (!empty($activity)) {
1443                      // Finally load the cm specific navigaton information
1444                      $this->load_activity($cm, $course, $activity);
1445                      // Check if we have an active ndoe
1446                      if (!$activity->contains_active_node() && !$activity->search_for_active_node()) {
1447                          // And make the activity node active.
1448                          $activity->make_active();
1449                      }
1450                  }
1451                  break;
1452              case CONTEXT_USER :
1453                  if ($issite) {
1454                      // The users profile information etc is already loaded
1455                      // for the front page.
1456                      break;
1457                  }
1458                  $course = $this->page->course;
1459                  // Load the course associated with the user into the navigation
1460                  $coursenode = $this->add_course($course, false, self::COURSE_CURRENT);
1461  
1462                  // If the course wasn't added then don't try going any further.
1463                  if (!$coursenode) {
1464                      $canviewcourseprofile = false;
1465                      break;
1466                  }
1467  
1468                  // If the user is not enrolled then we only want to show the
1469                  // course node and not populate it.
1470                  if (!can_access_course($course, null, '', true)) {
1471                      $coursenode->make_active();
1472                      $canviewcourseprofile = false;
1473                      break;
1474                  }
1475                  $this->add_course_essentials($coursenode, $course);
1476                  $this->load_course_sections($course, $coursenode);
1477                  break;
1478          }
1479  
1480          // Load for the current user
1481          $this->load_for_user();
1482          if ($this->page->context->contextlevel >= CONTEXT_COURSE && $this->page->context->instanceid != $SITE->id && $canviewcourseprofile) {
1483              $this->load_for_user(null, true);
1484          }
1485          // Load each extending user into the navigation.
1486          foreach ($this->extendforuser as $user) {
1487              if ($user->id != $USER->id) {
1488                  $this->load_for_user($user);
1489              }
1490          }
1491  
1492          // Give the local plugins a chance to include some navigation if they want.
1493          $this->load_local_plugin_navigation();
1494  
1495          // Remove any empty root nodes
1496          foreach ($this->rootnodes as $node) {
1497              // Dont remove the home node
1498              /** @var navigation_node $node */
1499              if (!in_array($node->key, ['home', 'myhome']) && !$node->has_children() && !$node->isactive) {
1500                  $node->remove();
1501              }
1502          }
1503  
1504          if (!$this->contains_active_node()) {
1505              $this->search_for_active_node();
1506          }
1507  
1508          // If the user is not logged in modify the navigation structure as detailed
1509          // in {@link http://docs.moodle.org/dev/Navigation_2.0_structure}
1510          if (!isloggedin()) {
1511              $activities = clone($this->rootnodes['site']->children);
1512              $this->rootnodes['site']->remove();
1513              $children = clone($this->children);
1514              $this->children = new navigation_node_collection();
1515              foreach ($activities as $child) {
1516                  $this->children->add($child);
1517              }
1518              foreach ($children as $child) {
1519                  $this->children->add($child);
1520              }
1521          }
1522          return true;
1523      }
1524  
1525      /**
1526       * This function gives local plugins an opportunity to modify navigation.
1527       */
1528      protected function load_local_plugin_navigation() {
1529          foreach (get_plugin_list_with_function('local', 'extend_navigation') as $function) {
1530              $function($this);
1531          }
1532      }
1533  
1534      /**
1535       * Returns true if the current user is a parent of the user being currently viewed.
1536       *
1537       * If the current user is not viewing another user, or if the current user does not hold any parent roles over the
1538       * other user being viewed this function returns false.
1539       * In order to set the user for whom we are checking against you must call {@link set_userid_for_parent_checks()}
1540       *
1541       * @since Moodle 2.4
1542       * @return bool
1543       */
1544      protected function current_user_is_parent_role() {
1545          global $USER, $DB;
1546          if ($this->useridtouseforparentchecks && $this->useridtouseforparentchecks != $USER->id) {
1547              $usercontext = context_user::instance($this->useridtouseforparentchecks, MUST_EXIST);
1548              if (!has_capability('moodle/user:viewdetails', $usercontext)) {
1549                  return false;
1550              }
1551              if ($DB->record_exists('role_assignments', array('userid' => $USER->id, 'contextid' => $usercontext->id))) {
1552                  return true;
1553              }
1554          }
1555          return false;
1556      }
1557  
1558      /**
1559       * Returns true if courses should be shown within categories on the navigation.
1560       *
1561       * @param bool $ismycourse Set to true if you are calculating this for a course.
1562       * @return bool
1563       */
1564      protected function show_categories($ismycourse = false) {
1565          global $CFG, $DB;
1566          if ($ismycourse) {
1567              return $this->show_my_categories();
1568          }
1569          if ($this->showcategories === null) {
1570              $show = false;
1571              if ($this->page->context->contextlevel == CONTEXT_COURSECAT) {
1572                  $show = true;
1573              } else if (!empty($CFG->navshowcategories) && $DB->count_records('course_categories') > 1) {
1574                  $show = true;
1575              }
1576              $this->showcategories = $show;
1577          }
1578          return $this->showcategories;
1579      }
1580  
1581      /**
1582       * Returns true if we should show categories in the My Courses branch.
1583       * @return bool
1584       */
1585      protected function show_my_categories() {
1586          global $CFG;
1587          if ($this->showmycategories === null) {
1588              $this->showmycategories = !empty($CFG->navshowmycoursecategories) && !core_course_category::is_simple_site();
1589          }
1590          return $this->showmycategories;
1591      }
1592  
1593      /**
1594       * Loads the courses in Moodle into the navigation.
1595       *
1596       * @global moodle_database $DB
1597       * @param string|array $categoryids An array containing categories to load courses
1598       *                     for, OR null to load courses for all categories.
1599       * @return array An array of navigation_nodes one for each course
1600       */
1601      protected function load_all_courses($categoryids = null) {
1602          global $CFG, $DB, $SITE;
1603  
1604          // Work out the limit of courses.
1605          $limit = 20;
1606          if (!empty($CFG->navcourselimit)) {
1607              $limit = $CFG->navcourselimit;
1608          }
1609  
1610          $toload = (empty($CFG->navshowallcourses))?self::LOAD_ROOT_CATEGORIES:self::LOAD_ALL_CATEGORIES;
1611  
1612          // If we are going to show all courses AND we are showing categories then
1613          // to save us repeated DB calls load all of the categories now
1614          if ($this->show_categories()) {
1615              $this->load_all_categories($toload);
1616          }
1617  
1618          // Will be the return of our efforts
1619          $coursenodes = array();
1620  
1621          // Check if we need to show categories.
1622          if ($this->show_categories()) {
1623              // Hmmm we need to show categories... this is going to be painful.
1624              // We now need to fetch up to $limit courses for each category to
1625              // be displayed.
1626              if ($categoryids !== null) {
1627                  if (!is_array($categoryids)) {
1628                      $categoryids = array($categoryids);
1629                  }
1630                  list($categorywhere, $categoryparams) = $DB->get_in_or_equal($categoryids, SQL_PARAMS_NAMED, 'cc');
1631                  $categorywhere = 'WHERE cc.id '.$categorywhere;
1632              } else if ($toload == self::LOAD_ROOT_CATEGORIES) {
1633                  $categorywhere = 'WHERE cc.depth = 1 OR cc.depth = 2';
1634                  $categoryparams = array();
1635              } else {
1636                  $categorywhere = '';
1637                  $categoryparams = array();
1638              }
1639  
1640              // First up we are going to get the categories that we are going to
1641              // need so that we can determine how best to load the courses from them.
1642              $sql = "SELECT cc.id, COUNT(c.id) AS coursecount
1643                          FROM {course_categories} cc
1644                      LEFT JOIN {course} c ON c.category = cc.id
1645                              {$categorywhere}
1646                      GROUP BY cc.id";
1647              $categories = $DB->get_recordset_sql($sql, $categoryparams);
1648              $fullfetch = array();
1649              $partfetch = array();
1650              foreach ($categories as $category) {
1651                  if (!$this->can_add_more_courses_to_category($category->id)) {
1652                      continue;
1653                  }
1654                  if ($category->coursecount > $limit * 5) {
1655                      $partfetch[] = $category->id;
1656                  } else if ($category->coursecount > 0) {
1657                      $fullfetch[] = $category->id;
1658                  }
1659              }
1660              $categories->close();
1661  
1662              if (count($fullfetch)) {
1663                  // First up fetch all of the courses in categories where we know that we are going to
1664                  // need the majority of courses.
1665                  list($categoryids, $categoryparams) = $DB->get_in_or_equal($fullfetch, SQL_PARAMS_NAMED, 'lcategory');
1666                  $ccselect = ', ' . context_helper::get_preload_record_columns_sql('ctx');
1667                  $ccjoin = "LEFT JOIN {context} ctx ON (ctx.instanceid = c.id AND ctx.contextlevel = :contextlevel)";
1668                  $categoryparams['contextlevel'] = CONTEXT_COURSE;
1669                  $sql = "SELECT c.id, c.sortorder, c.visible, c.fullname, c.shortname, c.category $ccselect
1670                              FROM {course} c
1671                                  $ccjoin
1672                              WHERE c.category {$categoryids}
1673                          ORDER BY c.sortorder ASC";
1674                  $coursesrs = $DB->get_recordset_sql($sql, $categoryparams);
1675                  foreach ($coursesrs as $course) {
1676                      if ($course->id == $SITE->id) {
1677                          // This should not be necessary, frontpage is not in any category.
1678                          continue;
1679                      }
1680                      if (array_key_exists($course->id, $this->addedcourses)) {
1681                          // It is probably better to not include the already loaded courses
1682                          // directly in SQL because inequalities may confuse query optimisers
1683                          // and may interfere with query caching.
1684                          continue;
1685                      }
1686                      if (!$this->can_add_more_courses_to_category($course->category)) {
1687                          continue;
1688                      }
1689                      context_helper::preload_from_record($course);
1690                      if (!$course->visible && !is_role_switched($course->id) && !has_capability('moodle/course:viewhiddencourses', context_course::instance($course->id))) {
1691                          continue;
1692                      }
1693                      $coursenodes[$course->id] = $this->add_course($course);
1694                  }
1695                  $coursesrs->close();
1696              }
1697  
1698              if (count($partfetch)) {
1699                  // Next we will work our way through the categories where we will likely only need a small
1700                  // proportion of the courses.
1701                  foreach ($partfetch as $categoryid) {
1702                      $ccselect = ', ' . context_helper::get_preload_record_columns_sql('ctx');
1703                      $ccjoin = "LEFT JOIN {context} ctx ON (ctx.instanceid = c.id AND ctx.contextlevel = :contextlevel)";
1704                      $sql = "SELECT c.id, c.sortorder, c.visible, c.fullname, c.shortname, c.category $ccselect
1705                                  FROM {course} c
1706                                      $ccjoin
1707                                  WHERE c.category = :categoryid
1708                              ORDER BY c.sortorder ASC";
1709                      $courseparams = array('categoryid' => $categoryid, 'contextlevel' => CONTEXT_COURSE);
1710                      $coursesrs = $DB->get_recordset_sql($sql, $courseparams, 0, $limit * 5);
1711                      foreach ($coursesrs as $course) {
1712                          if ($course->id == $SITE->id) {
1713                              // This should not be necessary, frontpage is not in any category.
1714                              continue;
1715                          }
1716                          if (array_key_exists($course->id, $this->addedcourses)) {
1717                              // It is probably better to not include the already loaded courses
1718                              // directly in SQL because inequalities may confuse query optimisers
1719                              // and may interfere with query caching.
1720                              // This also helps to respect expected $limit on repeated executions.
1721                              continue;
1722                          }
1723                          if (!$this->can_add_more_courses_to_category($course->category)) {
1724                              break;
1725                          }
1726                          context_helper::preload_from_record($course);
1727                          if (!$course->visible && !is_role_switched($course->id) && !has_capability('moodle/course:viewhiddencourses', context_course::instance($course->id))) {
1728                              continue;
1729                          }
1730                          $coursenodes[$course->id] = $this->add_course($course);
1731                      }
1732                      $coursesrs->close();
1733                  }
1734              }
1735          } else {
1736              // Prepare the SQL to load the courses and their contexts
1737              list($courseids, $courseparams) = $DB->get_in_or_equal(array_keys($this->addedcourses), SQL_PARAMS_NAMED, 'lc', false);
1738              $ccselect = ', ' . context_helper::get_preload_record_columns_sql('ctx');
1739              $ccjoin = "LEFT JOIN {context} ctx ON (ctx.instanceid = c.id AND ctx.contextlevel = :contextlevel)";
1740              $courseparams['contextlevel'] = CONTEXT_COURSE;
1741              $sql = "SELECT c.id, c.sortorder, c.visible, c.fullname, c.shortname, c.category $ccselect
1742                          FROM {course} c
1743                              $ccjoin
1744                          WHERE c.id {$courseids}
1745                      ORDER BY c.sortorder ASC";
1746              $coursesrs = $DB->get_recordset_sql($sql, $courseparams);
1747              foreach ($coursesrs as $course) {
1748                  if ($course->id == $SITE->id) {
1749                      // frotpage is not wanted here
1750                      continue;
1751                  }
1752                  if ($this->page->course && ($this->page->course->id == $course->id)) {
1753                      // Don't include the currentcourse in this nodelist - it's displayed in the Current course node
1754                      continue;
1755                  }
1756                  context_helper::preload_from_record($course);
1757                  if (!$course->visible && !is_role_switched($course->id) && !has_capability('moodle/course:viewhiddencourses', context_course::instance($course->id))) {
1758                      continue;
1759                  }
1760                  $coursenodes[$course->id] = $this->add_course($course);
1761                  if (count($coursenodes) >= $limit) {
1762                      break;
1763                  }
1764              }
1765              $coursesrs->close();
1766          }
1767  
1768          return $coursenodes;
1769      }
1770  
1771      /**
1772       * Returns true if more courses can be added to the provided category.
1773       *
1774       * @param int|navigation_node|stdClass $category
1775       * @return bool
1776       */
1777      protected function can_add_more_courses_to_category($category) {
1778          global $CFG;
1779          $limit = 20;
1780          if (!empty($CFG->navcourselimit)) {
1781              $limit = (int)$CFG->navcourselimit;
1782          }
1783          if (is_numeric($category)) {
1784              if (!array_key_exists($category, $this->addedcategories)) {
1785                  return true;
1786              }
1787              $coursecount = count($this->addedcategories[$category]->children->type(self::TYPE_COURSE));
1788          } else if ($category instanceof navigation_node) {
1789              if (($category->type != self::TYPE_CATEGORY) || ($category->type != self::TYPE_MY_CATEGORY)) {
1790                  return false;
1791              }
1792              $coursecount = count($category->children->type(self::TYPE_COURSE));
1793          } else if (is_object($category) && property_exists($category,'id')) {
1794              $coursecount = count($this->addedcategories[$category->id]->children->type(self::TYPE_COURSE));
1795          }
1796          return ($coursecount <= $limit);
1797      }
1798  
1799      /**
1800       * Loads all categories (top level or if an id is specified for that category)
1801       *
1802       * @param int $categoryid The category id to load or null/0 to load all base level categories
1803       * @param bool $showbasecategories If set to true all base level categories will be loaded as well
1804       *        as the requested category and any parent categories.
1805       * @return navigation_node|void returns a navigation node if a category has been loaded.
1806       */
1807      protected function load_all_categories($categoryid = self::LOAD_ROOT_CATEGORIES, $showbasecategories = false) {
1808          global $CFG, $DB;
1809  
1810          // Check if this category has already been loaded
1811          if ($this->allcategoriesloaded || ($categoryid < 1 && $this->is_category_fully_loaded($categoryid))) {
1812              return true;
1813          }
1814  
1815          $catcontextsql = context_helper::get_preload_record_columns_sql('ctx');
1816          $sqlselect = "SELECT cc.*, $catcontextsql
1817                        FROM {course_categories} cc
1818                        JOIN {context} ctx ON cc.id = ctx.instanceid";
1819          $sqlwhere = "WHERE ctx.contextlevel = ".CONTEXT_COURSECAT;
1820          $sqlorder = "ORDER BY cc.depth ASC, cc.sortorder ASC, cc.id ASC";
1821          $params = array();
1822  
1823          $categoriestoload = array();
1824          if ($categoryid == self::LOAD_ALL_CATEGORIES) {
1825              // We are going to load all categories regardless... prepare to fire
1826              // on the database server!
1827          } else if ($categoryid == self::LOAD_ROOT_CATEGORIES) { // can be 0
1828              // We are going to load all of the first level categories (categories without parents)
1829              $sqlwhere .= " AND cc.parent = 0";
1830          } else if (array_key_exists($categoryid, $this->addedcategories)) {
1831              // The category itself has been loaded already so we just need to ensure its subcategories
1832              // have been loaded
1833              $addedcategories = $this->addedcategories;
1834              unset($addedcategories[$categoryid]);
1835              if (count($addedcategories) > 0) {
1836                  list($sql, $params) = $DB->get_in_or_equal(array_keys($addedcategories), SQL_PARAMS_NAMED, 'parent', false);
1837                  if ($showbasecategories) {
1838                      // We need to include categories with parent = 0 as well
1839                      $sqlwhere .= " AND (cc.parent = :categoryid OR cc.parent = 0) AND cc.parent {$sql}";
1840                  } else {
1841                      // All we need is categories that match the parent
1842                      $sqlwhere .= " AND cc.parent = :categoryid AND cc.parent {$sql}";
1843                  }
1844              }
1845              $params['categoryid'] = $categoryid;
1846          } else {
1847              // This category hasn't been loaded yet so we need to fetch it, work out its category path
1848              // and load this category plus all its parents and subcategories
1849              $category = $DB->get_record('course_categories', array('id' => $categoryid), 'path', MUST_EXIST);
1850              $categoriestoload = explode('/', trim($category->path, '/'));
1851              list($select, $params) = $DB->get_in_or_equal($categoriestoload);
1852              // We are going to use select twice so double the params
1853              $params = array_merge($params, $params);
1854              $basecategorysql = ($showbasecategories)?' OR cc.depth = 1':'';
1855              $sqlwhere .= " AND (cc.id {$select} OR cc.parent {$select}{$basecategorysql})";
1856          }
1857  
1858          $categoriesrs = $DB->get_recordset_sql("$sqlselect $sqlwhere $sqlorder", $params);
1859          $categories = array();
1860          foreach ($categoriesrs as $category) {
1861              // Preload the context.. we'll need it when adding the category in order
1862              // to format the category name.
1863              context_helper::preload_from_record($category);
1864              if (array_key_exists($category->id, $this->addedcategories)) {
1865                  // Do nothing, its already been added.
1866              } else if ($category->parent == '0') {
1867                  // This is a root category lets add it immediately
1868                  $this->add_category($category, $this->rootnodes['courses']);
1869              } else if (array_key_exists($category->parent, $this->addedcategories)) {
1870                  // This categories parent has already been added we can add this immediately
1871                  $this->add_category($category, $this->addedcategories[$category->parent]);
1872              } else {
1873                  $categories[] = $category;
1874              }
1875          }
1876          $categoriesrs->close();
1877  
1878          // Now we have an array of categories we need to add them to the navigation.
1879          while (!empty($categories)) {
1880              $category = reset($categories);
1881              if (array_key_exists($category->id, $this->addedcategories)) {
1882                  // Do nothing
1883              } else if ($category->parent == '0') {
1884                  $this->add_category($category, $this->rootnodes['courses']);
1885              } else if (array_key_exists($category->parent, $this->addedcategories)) {
1886                  $this->add_category($category, $this->addedcategories[$category->parent]);
1887              } else {
1888                  // This category isn't in the navigation and niether is it's parent (yet).
1889                  // We need to go through the category path and add all of its components in order.
1890                  $path = explode('/', trim($category->path, '/'));
1891                  foreach ($path as $catid) {
1892                      if (!array_key_exists($catid, $this->addedcategories)) {
1893                          // This category isn't in the navigation yet so add it.
1894                          $subcategory = $categories[$catid];
1895                          if ($subcategory->parent == '0') {
1896                              // Yay we have a root category - this likely means we will now be able
1897                              // to add categories without problems.
1898                              $this->add_category($subcategory, $this->rootnodes['courses']);
1899                          } else if (array_key_exists($subcategory->parent, $this->addedcategories)) {
1900                              // The parent is in the category (as we'd expect) so add it now.
1901                              $this->add_category($subcategory, $this->addedcategories[$subcategory->parent]);
1902                              // Remove the category from the categories array.
1903                              unset($categories[$catid]);
1904                          } else {
1905                              // We should never ever arrive here - if we have then there is a bigger
1906                              // problem at hand.
1907                              throw new coding_exception('Category path order is incorrect and/or there are missing categories');
1908                          }
1909                      }
1910                  }
1911              }
1912              // Remove the category from the categories array now that we know it has been added.
1913              unset($categories[$category->id]);
1914          }
1915          if ($categoryid === self::LOAD_ALL_CATEGORIES) {
1916              $this->allcategoriesloaded = true;
1917          }
1918          // Check if there are any categories to load.
1919          if (count($categoriestoload) > 0) {
1920              $readytoloadcourses = array();
1921              foreach ($categoriestoload as $category) {
1922                  if ($this->can_add_more_courses_to_category($category)) {
1923                      $readytoloadcourses[] = $category;
1924                  }
1925              }
1926              if (count($readytoloadcourses)) {
1927                  $this->load_all_courses($readytoloadcourses);
1928              }
1929          }
1930  
1931          // Look for all categories which have been loaded
1932          if (!empty($this->addedcategories)) {
1933              $categoryids = array();
1934              foreach ($this->addedcategories as $category) {
1935                  if ($this->can_add_more_courses_to_category($category)) {
1936                      $categoryids[] = $category->key;
1937                  }
1938              }
1939              if ($categoryids) {
1940                  list($categoriessql, $params) = $DB->get_in_or_equal($categoryids, SQL_PARAMS_NAMED);
1941                  $params['limit'] = (!empty($CFG->navcourselimit))?$CFG->navcourselimit:20;
1942                  $sql = "SELECT cc.id, COUNT(c.id) AS coursecount
1943                            FROM {course_categories} cc
1944                            JOIN {course} c ON c.category = cc.id
1945                           WHERE cc.id {$categoriessql}
1946                        GROUP BY cc.id
1947                          HAVING COUNT(c.id) > :limit";
1948                  $excessivecategories = $DB->get_records_sql($sql, $params);
1949                  foreach ($categories as &$category) {
1950                      if (array_key_exists($category->key, $excessivecategories) && !$this->can_add_more_courses_to_category($category)) {
1951                          $url = new moodle_url('/course/index.php', array('categoryid' => $category->key));
1952                          $category->add(get_string('viewallcourses'), $url, self::TYPE_SETTING);
1953                      }
1954                  }
1955              }
1956          }
1957      }
1958  
1959      /**
1960       * Adds a structured category to the navigation in the correct order/place
1961       *
1962       * @param stdClass $category category to be added in navigation.
1963       * @param navigation_node $parent parent navigation node
1964       * @param int $nodetype type of node, if category is under MyHome then it's TYPE_MY_CATEGORY
1965       * @return void.
1966       */
1967      protected function add_category(stdClass $category, navigation_node $parent, $nodetype = self::TYPE_CATEGORY) {
1968          global $CFG;
1969          if (array_key_exists($category->id, $this->addedcategories)) {
1970              return;
1971          }
1972          $canview = core_course_category::can_view_category($category);
1973          $url = $canview ? new moodle_url('/course/index.php', array('categoryid' => $category->id)) : null;
1974          $context = \context_helper::get_navigation_filter_context(context_coursecat::instance($category->id));
1975          $categoryname = $canview ? format_string($category->name, true, ['context' => $context]) :
1976              get_string('categoryhidden');
1977          $categorynode = $parent->add($categoryname, $url, $nodetype, $categoryname, $category->id);
1978          if (!$canview) {
1979              // User does not have required capabilities to view category.
1980              $categorynode->display = false;
1981          } else if (!$category->visible) {
1982              // Category is hidden but user has capability to view hidden categories.
1983              $categorynode->hidden = true;
1984          }
1985          $this->addedcategories[$category->id] = $categorynode;
1986      }
1987  
1988      /**
1989       * Loads the given course into the navigation
1990       *
1991       * @param stdClass $course
1992       * @return navigation_node
1993       */
1994      protected function load_course(stdClass $course) {
1995          global $SITE;
1996          if ($course->id == $SITE->id) {
1997              // This is always loaded during initialisation
1998              return $this->rootnodes['site'];
1999          } else if (array_key_exists($course->id, $this->addedcourses)) {
2000              // The course has already been loaded so return a reference
2001              return $this->addedcourses[$course->id];
2002          } else {
2003              // Add the course
2004              return $this->add_course($course);
2005          }
2006      }
2007  
2008      /**
2009       * Loads all of the courses section into the navigation.
2010       *
2011       * This function calls method from current course format, see
2012       * {@link format_base::extend_course_navigation()}
2013       * If course module ($cm) is specified but course format failed to create the node,
2014       * the activity node is created anyway.
2015       *
2016       * By default course formats call the method {@link global_navigation::load_generic_course_sections()}
2017       *
2018       * @param stdClass $course Database record for the course
2019       * @param navigation_node $coursenode The course node within the navigation
2020       * @param null|int $sectionnum If specified load the contents of section with this relative number
2021       * @param null|cm_info $cm If specified make sure that activity node is created (either
2022       *    in containg section or by calling load_stealth_activity() )
2023       */
2024      protected function load_course_sections(stdClass $course, navigation_node $coursenode, $sectionnum = null, $cm = null) {
2025          global $CFG, $SITE;
2026          require_once($CFG->dirroot.'/course/lib.php');
2027          if (isset($cm->sectionnum)) {
2028              $sectionnum = $cm->sectionnum;
2029          }
2030          if ($sectionnum !== null) {
2031              $this->includesectionnum = $sectionnum;
2032          }
2033          course_get_format($course)->extend_course_navigation($this, $coursenode, $sectionnum, $cm);
2034          if (isset($cm->id)) {
2035              $activity = $coursenode->find($cm->id, self::TYPE_ACTIVITY);
2036              if (empty($activity)) {
2037                  $activity = $this->load_stealth_activity($coursenode, get_fast_modinfo($course));
2038              }
2039          }
2040     }
2041  
2042      /**
2043       * Generates an array of sections and an array of activities for the given course.
2044       *
2045       * This method uses the cache to improve performance and avoid the get_fast_modinfo call
2046       *
2047       * @param stdClass $course
2048       * @return array Array($sections, $activities)
2049       */
2050      protected function generate_sections_and_activities(stdClass $course) {
2051          global $CFG;
2052          require_once($CFG->dirroot.'/course/lib.php');
2053  
2054          $modinfo = get_fast_modinfo($course);
2055          $sections = $modinfo->get_section_info_all();
2056  
2057          // For course formats using 'numsections' trim the sections list
2058          $courseformatoptions = course_get_format($course)->get_format_options();
2059          if (isset($courseformatoptions['numsections'])) {
2060              $sections = array_slice($sections, 0, $courseformatoptions['numsections']+1, true);
2061          }
2062  
2063          $activities = array();
2064  
2065          foreach ($sections as $key => $section) {
2066              // Clone and unset summary to prevent $SESSION bloat (MDL-31802).
2067              $sections[$key] = clone($section);
2068              unset($sections[$key]->summary);
2069              $sections[$key]->hasactivites = false;
2070              if (!array_key_exists($section->section, $modinfo->sections)) {
2071                  continue;
2072              }
2073              foreach ($modinfo->sections[$section->section] as $cmid) {
2074                  $cm = $modinfo->cms[$cmid];
2075                  $activity = new stdClass;
2076                  $activity->id = $cm->id;
2077                  $activity->course = $course->id;
2078                  $activity->section = $section->section;
2079                  $activity->name = $cm->name;
2080                  $activity->icon = $cm->icon;
2081                  $activity->iconcomponent = $cm->iconcomponent;
2082                  $activity->hidden = (!$cm->visible);
2083                  $activity->modname = $cm->modname;
2084                  $activity->nodetype = navigation_node::NODETYPE_LEAF;
2085                  $activity->onclick = $cm->onclick;
2086                  $url = $cm->url;
2087                  if (!$url) {
2088                      $activity->url = null;
2089                      $activity->display = false;
2090                  } else {
2091                      $activity->url = $url->out();
2092                      $activity->display = $cm->is_visible_on_course_page() ? true : false;
2093                      if (self::module_extends_navigation($cm->modname)) {
2094                          $activity->nodetype = navigation_node::NODETYPE_BRANCH;
2095                      }
2096                  }
2097                  $activities[$cmid] = $activity;
2098                  if ($activity->display) {
2099                      $sections[$key]->hasactivites = true;
2100                  }
2101              }
2102          }
2103  
2104          return array($sections, $activities);
2105      }
2106  
2107      /**
2108       * Generically loads the course sections into the course's navigation.
2109       *
2110       * @param stdClass $course
2111       * @param navigation_node $coursenode
2112       * @return array An array of course section nodes
2113       */
2114      public function load_generic_course_sections(stdClass $course, navigation_node $coursenode) {
2115          global $CFG, $DB, $USER, $SITE;
2116          require_once($CFG->dirroot.'/course/lib.php');
2117  
2118          list($sections, $activities) = $this->generate_sections_and_activities($course);
2119  
2120          $navigationsections = array();
2121          foreach ($sections as $sectionid => $section) {
2122              $section = clone($section);
2123              if ($course->id == $SITE->id) {
2124                  $this->load_section_activities($coursenode, $section->section, $activities);
2125              } else {
2126                  if (!$section->uservisible || (!$this->showemptysections &&
2127                          !$section->hasactivites && $this->includesectionnum !== $section->section)) {
2128                      continue;
2129                  }
2130  
2131                  $sectionname = get_section_name($course, $section);
2132                  $url = course_get_url($course, $section->section, array('navigation' => true));
2133  
2134                  $sectionnode = $coursenode->add($sectionname, $url, navigation_node::TYPE_SECTION,
2135                      null, $section->id, new pix_icon('i/section', ''));
2136                  $sectionnode->nodetype = navigation_node::NODETYPE_BRANCH;
2137                  $sectionnode->hidden = (!$section->visible || !$section->available);
2138                  if ($this->includesectionnum !== false && $this->includesectionnum == $section->section) {
2139                      $this->load_section_activities($sectionnode, $section->section, $activities);
2140                  }
2141                  $section->sectionnode = $sectionnode;
2142                  $navigationsections[$sectionid] = $section;
2143              }
2144          }
2145          return $navigationsections;
2146      }
2147  
2148      /**
2149       * Loads all of the activities for a section into the navigation structure.
2150       *
2151       * @param navigation_node $sectionnode
2152       * @param int $sectionnumber
2153       * @param array $activities An array of activites as returned by {@link global_navigation::generate_sections_and_activities()}
2154       * @param stdClass $course The course object the section and activities relate to.
2155       * @return array Array of activity nodes
2156       */
2157      protected function load_section_activities(navigation_node $sectionnode, $sectionnumber, array $activities, $course = null) {
2158          global $CFG, $SITE;
2159          // A static counter for JS function naming
2160          static $legacyonclickcounter = 0;
2161  
2162          $activitynodes = array();
2163          if (empty($activities)) {
2164              return $activitynodes;
2165          }
2166  
2167          if (!is_object($course)) {
2168              $activity = reset($activities);
2169              $courseid = $activity->course;
2170          } else {
2171              $courseid = $course->id;
2172          }
2173          $showactivities = ($courseid != $SITE->id || !empty($CFG->navshowfrontpagemods));
2174  
2175          foreach ($activities as $activity) {
2176              if ($activity->section != $sectionnumber) {
2177                  continue;
2178              }
2179              if ($activity->icon) {
2180                  $icon = new pix_icon($activity->icon, get_string('modulename', $activity->modname), $activity->iconcomponent);
2181              } else {
2182                  $icon = new pix_icon('icon', get_string('modulename', $activity->modname), $activity->modname);
2183              }
2184  
2185              // Prepare the default name and url for the node
2186              $displaycontext = \context_helper::get_navigation_filter_context(context_module::instance($activity->id));
2187              $activityname = format_string($activity->name, true, ['context' => $displaycontext]);
2188              $action = new moodle_url($activity->url);
2189  
2190              // Check if the onclick property is set (puke!)
2191              if (!empty($activity->onclick)) {
2192                  // Increment the counter so that we have a unique number.
2193                  $legacyonclickcounter++;
2194                  // Generate the function name we will use
2195                  $functionname = 'legacy_activity_onclick_handler_'.$legacyonclickcounter;
2196                  $propogrationhandler = '';
2197                  // Check if we need to cancel propogation. Remember inline onclick
2198                  // events would return false if they wanted to prevent propogation and the
2199                  // default action.
2200                  if (strpos($activity->onclick, 'return false')) {
2201                      $propogrationhandler = 'e.halt();';
2202                  }
2203                  // Decode the onclick - it has already been encoded for display (puke)
2204                  $onclick = htmlspecialchars_decode($activity->onclick, ENT_QUOTES);
2205                  // Build the JS function the click event will call
2206                  $jscode = "function {$functionname}(e) { $propogrationhandler $onclick }";
2207                  $this->page->requires->js_amd_inline($jscode);
2208                  // Override the default url with the new action link
2209                  $action = new action_link($action, $activityname, new component_action('click', $functionname));
2210              }
2211  
2212              $activitynode = $sectionnode->add($activityname, $action, navigation_node::TYPE_ACTIVITY, null, $activity->id, $icon);
2213              $activitynode->title(get_string('modulename', $activity->modname));
2214              $activitynode->hidden = $activity->hidden;
2215              $activitynode->display = $showactivities && $activity->display;
2216              $activitynode->nodetype = $activity->nodetype;
2217              $activitynodes[$activity->id] = $activitynode;
2218          }
2219  
2220          return $activitynodes;
2221      }
2222      /**
2223       * Loads a stealth module from unavailable section
2224       * @param navigation_node $coursenode
2225       * @param stdClass $modinfo
2226       * @return navigation_node or null if not accessible
2227       */
2228      protected function load_stealth_activity(navigation_node $coursenode, $modinfo) {
2229          if (empty($modinfo->cms[$this->page->cm->id])) {
2230              return null;
2231          }
2232          $cm = $modinfo->cms[$this->page->cm->id];
2233          if ($cm->icon) {
2234              $icon = new pix_icon($cm->icon, get_string('modulename', $cm->modname), $cm->iconcomponent);
2235          } else {
2236              $icon = new pix_icon('icon', get_string('modulename', $cm->modname), $cm->modname);
2237          }
2238          $url = $cm->url;
2239          $activitynode = $coursenode->add(format_string($cm->name), $url, navigation_node::TYPE_ACTIVITY, null, $cm->id, $icon);
2240          $activitynode->title(get_string('modulename', $cm->modname));
2241          $activitynode->hidden = (!$cm->visible);
2242          if (!$cm->is_visible_on_course_page()) {
2243              // Do not show any error here, let the page handle exception that activity is not visible for the current user.
2244              // Also there may be no exception at all in case when teacher is logged in as student.
2245              $activitynode->display = false;
2246          } else if (!$url) {
2247              // Don't show activities that don't have links!
2248              $activitynode->display = false;
2249          } else if (self::module_extends_navigation($cm->modname)) {
2250              $activitynode->nodetype = navigation_node::NODETYPE_BRANCH;
2251          }
2252          return $activitynode;
2253      }
2254      /**
2255       * Loads the navigation structure for the given activity into the activities node.
2256       *
2257       * This method utilises a callback within the modules lib.php file to load the
2258       * content specific to activity given.
2259       *
2260       * The callback is a method: {modulename}_extend_navigation()
2261       * Examples:
2262       *  * {@link forum_extend_navigation()}
2263       *  * {@link workshop_extend_navigation()}
2264       *
2265       * @param cm_info|stdClass $cm
2266       * @param stdClass $course
2267       * @param navigation_node $activity
2268       * @return bool
2269       */
2270      protected function load_activity($cm, stdClass $course, navigation_node $activity) {
2271          global $CFG, $DB;
2272  
2273          // make sure we have a $cm from get_fast_modinfo as this contains activity access details
2274          if (!($cm instanceof cm_info)) {
2275              $modinfo = get_fast_modinfo($course);
2276              $cm = $modinfo->get_cm($cm->id);
2277          }
2278          $activity->nodetype = navigation_node::NODETYPE_LEAF;
2279          $activity->make_active();
2280          $file = $CFG->dirroot.'/mod/'.$cm->modname.'/lib.php';
2281          $function = $cm->modname.'_extend_navigation';
2282  
2283          if (file_exists($file)) {
2284              require_once($file);
2285              if (function_exists($function)) {
2286                  $activtyrecord = $DB->get_record($cm->modname, array('id' => $cm->instance), '*', MUST_EXIST);
2287                  $function($activity, $course, $activtyrecord, $cm);
2288              }
2289          }
2290  
2291          // Allow the active advanced grading method plugin to append module navigation
2292          $featuresfunc = $cm->modname.'_supports';
2293          if (function_exists($featuresfunc) && $featuresfunc(FEATURE_ADVANCED_GRADING)) {
2294              require_once($CFG->dirroot.'/grade/grading/lib.php');
2295              $gradingman = get_grading_manager($cm->context,  'mod_'.$cm->modname);
2296              $gradingman->extend_navigation($this, $activity);
2297          }
2298  
2299          return $activity->has_children();
2300      }
2301      /**
2302       * Loads user specific information into the navigation in the appropriate place.
2303       *
2304       * If no user is provided the current user is assumed.
2305       *
2306       * @param stdClass $user
2307       * @param bool $forceforcontext probably force something to be loaded somewhere (ask SamH if not sure what this means)
2308       * @return bool
2309       */
2310      protected function load_for_user($user=null, $forceforcontext=false) {
2311          global $DB, $CFG, $USER, $SITE;
2312  
2313          require_once($CFG->dirroot . '/course/lib.php');
2314  
2315          if ($user === null) {
2316              // We can't require login here but if the user isn't logged in we don't
2317              // want to show anything
2318              if (!isloggedin() || isguestuser()) {
2319                  return false;
2320              }
2321              $user = $USER;
2322          } else if (!is_object($user)) {
2323              // If the user is not an object then get them from the database
2324              $select = context_helper::get_preload_record_columns_sql('ctx');
2325              $sql = "SELECT u.*, $select
2326                        FROM {user} u
2327                        JOIN {context} ctx ON u.id = ctx.instanceid
2328                       WHERE u.id = :userid AND
2329                             ctx.contextlevel = :contextlevel";
2330              $user = $DB->get_record_sql($sql, array('userid' => (int)$user, 'contextlevel' => CONTEXT_USER), MUST_EXIST);
2331              context_helper::preload_from_record($user);
2332          }
2333  
2334          $iscurrentuser = ($user->id == $USER->id);
2335  
2336          $usercontext = context_user::instance($user->id);
2337  
2338          // Get the course set against the page, by default this will be the site
2339          $course = $this->page->course;
2340          $baseargs = array('id'=>$user->id);
2341          if ($course->id != $SITE->id && (!$iscurrentuser || $forceforcontext)) {
2342              $coursenode = $this->add_course($course, false, self::COURSE_CURRENT);
2343              $baseargs['course'] = $course->id;
2344              $coursecontext = context_course::instance($course->id);
2345              $issitecourse = false;
2346          } else {
2347              // Load all categories and get the context for the system
2348              $coursecontext = context_system::instance();
2349              $issitecourse = true;
2350          }
2351  
2352          // Create a node to add user information under.
2353          $usersnode = null;
2354          if (!$issitecourse) {
2355              // Not the current user so add it to the participants node for the current course.
2356              $usersnode = $coursenode->get('participants', navigation_node::TYPE_CONTAINER);
2357              $userviewurl = new moodle_url('/user/view.php', $baseargs);
2358          } else if ($USER->id != $user->id) {
2359              // This is the site so add a users node to the root branch.
2360              $usersnode = $this->rootnodes['users'];
2361              if (course_can_view_participants($coursecontext)) {
2362                  $usersnode->action = new moodle_url('/user/index.php', array('id' => $course->id));
2363              }
2364              $userviewurl = new moodle_url('/user/profile.php', $baseargs);
2365          }
2366          if (!$usersnode) {
2367              // We should NEVER get here, if the course hasn't been populated
2368              // with a participants node then the navigaiton either wasn't generated
2369              // for it (you are missing a require_login or set_context call) or
2370              // you don't have access.... in the interests of no leaking informatin
2371              // we simply quit...
2372              return false;
2373          }
2374          // Add a branch for the current user.
2375          // Only reveal user details if $user is the current user, or a user to which the current user has access.
2376          $viewprofile = true;
2377          if (!$iscurrentuser) {
2378              require_once($CFG->dirroot . '/user/lib.php');
2379              if ($this->page->context->contextlevel == CONTEXT_USER && !has_capability('moodle/user:viewdetails', $usercontext) ) {
2380                  $viewprofile = false;
2381              } else if ($this->page->context->contextlevel != CONTEXT_USER && !user_can_view_profile($user, $course, $usercontext)) {
2382                  $viewprofile = false;
2383              }
2384              if (!$viewprofile) {
2385                  $viewprofile = user_can_view_profile($user, null, $usercontext);
2386              }
2387          }
2388  
2389          // Now, conditionally add the user node.
2390          if ($viewprofile) {
2391              $canseefullname = has_capability('moodle/site:viewfullnames', $coursecontext);
2392              $usernode = $usersnode->add(fullname($user, $canseefullname), $userviewurl, self::TYPE_USER, null, 'user' . $user->id);
2393          } else {
2394              $usernode = $usersnode->add(get_string('user'));
2395          }
2396  
2397          if ($this->page->context->contextlevel == CONTEXT_USER && $user->id == $this->page->context->instanceid) {
2398              $usernode->make_active();
2399          }
2400  
2401          // Add user information to the participants or user node.
2402          if ($issitecourse) {
2403  
2404              // If the user is the current user or has permission to view the details of the requested
2405              // user than add a view profile link.
2406              if ($iscurrentuser || has_capability('moodle/user:viewdetails', $coursecontext) ||
2407                      has_capability('moodle/user:viewdetails', $usercontext)) {
2408                  if ($issitecourse || ($iscurrentuser && !$forceforcontext)) {
2409                      $usernode->add(get_string('viewprofile'), new moodle_url('/user/profile.php', $baseargs));
2410                  } else {
2411                      $usernode->add(get_string('viewprofile'), new moodle_url('/user/view.php', $baseargs));
2412                  }
2413              }
2414  
2415              if (!empty($CFG->navadduserpostslinks)) {
2416                  // Add nodes for forum posts and discussions if the user can view either or both
2417                  // There are no capability checks here as the content of the page is based
2418                  // purely on the forums the current user has access too.
2419                  $forumtab = $usernode->add(get_string('forumposts', 'forum'));
2420                  $forumtab->add(get_string('posts', 'forum'), new moodle_url('/mod/forum/user.php', $baseargs));
2421                  $forumtab->add(get_string('discussions', 'forum'), new moodle_url('/mod/forum/user.php',
2422                          array_merge($baseargs, array('mode' => 'discussions'))));
2423              }
2424  
2425              // Add blog nodes.
2426              if (!empty($CFG->enableblogs)) {
2427                  if (!$this->cache->cached('userblogoptions'.$user->id)) {
2428                      require_once($CFG->dirroot.'/blog/lib.php');
2429                      // Get all options for the user.
2430                      $options = blog_get_options_for_user($user);
2431                      $this->cache->set('userblogoptions'.$user->id, $options);
2432                  } else {
2433                      $options = $this->cache->{'userblogoptions'.$user->id};
2434                  }
2435  
2436                  if (count($options) > 0) {
2437                      $blogs = $usernode->add(get_string('blogs', 'blog'), null, navigation_node::TYPE_CONTAINER);
2438                      foreach ($options as $type => $option) {
2439                          if ($type == "rss") {
2440                              $blogs->add($option['string'], $option['link'], settings_navigation::TYPE_SETTING, null, null,
2441                                      new pix_icon('i/rss', ''));
2442                          } else {
2443                              $blogs->add($option['string'], $option['link']);
2444                          }
2445                      }
2446                  }
2447              }
2448  
2449              // Add the messages link.
2450              // It is context based so can appear in the user's profile and in course participants information.
2451              if (!empty($CFG->messaging)) {
2452                  $messageargs = array('user1' => $USER->id);
2453                  if ($USER->id != $user->id) {
2454                      $messageargs['user2'] = $user->id;
2455                  }
2456                  $url = new moodle_url('/message/index.php', $messageargs);
2457                  $usernode->add(get_string('messages', 'message'), $url, self::TYPE_SETTING, null, 'messages');
2458              }
2459  
2460              // Add the "My private files" link.
2461              // This link doesn't have a unique display for course context so only display it under the user's profile.
2462              if ($issitecourse && $iscurrentuser && has_capability('moodle/user:manageownfiles', $usercontext)) {
2463                  $url = new moodle_url('/user/files.php');
2464                  $usernode->add(get_string('privatefiles'), $url, self::TYPE_SETTING, null, 'privatefiles');
2465              }
2466  
2467              // Add a node to view the users notes if permitted.
2468              if (!empty($CFG->enablenotes) &&
2469                      has_any_capability(array('moodle/notes:manage', 'moodle/notes:view'), $coursecontext)) {
2470                  $url = new moodle_url('/notes/index.php', array('user' => $user->id));
2471                  if ($coursecontext->instanceid != SITEID) {
2472                      $url->param('course', $coursecontext->instanceid);
2473                  }
2474                  $usernode->add(get_string('notes', 'notes'), $url);
2475              }
2476  
2477              // Show the grades node.
2478              if (($issitecourse && $iscurrentuser) || has_capability('moodle/user:viewdetails', $usercontext)) {
2479                  require_once($CFG->dirroot . '/user/lib.php');
2480                  // Set the grades node to link to the "Grades" page.
2481                  if ($course->id == SITEID) {
2482                      $url = user_mygrades_url($user->id, $course->id);
2483                  } else { // Otherwise we are in a course and should redirect to the user grade report (Activity report version).
2484                      $url = new moodle_url('/course/user.php', array('mode' => 'grade', 'id' => $course->id, 'user' => $user->id));
2485                  }
2486                  if ($USER->id != $user->id) {
2487                      $usernode->add(get_string('grades', 'grades'), $url, self::TYPE_SETTING, null, 'usergrades');
2488                  } else {
2489                      $usernode->add(get_string('grades', 'grades'), $url);
2490                  }
2491              }
2492  
2493              // If the user is the current user add the repositories for the current user.
2494              $hiddenfields = array_flip(explode(',', $CFG->hiddenuserfields));
2495              if (!$iscurrentuser &&
2496                      $course->id == $SITE->id &&
2497                      has_capability('moodle/user:viewdetails', $usercontext) &&
2498                      (!in_array('mycourses', $hiddenfields) || has_capability('moodle/user:viewhiddendetails', $coursecontext))) {
2499  
2500                  // Add view grade report is permitted.
2501                  $reports = core_component::get_plugin_list('gradereport');
2502                  arsort($reports); // User is last, we want to test it first.
2503  
2504                  $userscourses = enrol_get_users_courses($user->id, false, '*');
2505                  $userscoursesnode = $usernode->add(get_string('courses'));
2506  
2507                  $count = 0;
2508                  foreach ($userscourses as $usercourse) {
2509                      if ($count === (int)$CFG->navcourselimit) {
2510                          $url = new moodle_url('/user/profile.php', array('id' => $user->id, 'showallcourses' => 1));
2511                          $userscoursesnode->add(get_string('showallcourses'), $url);
2512                          break;
2513                      }
2514                      $count++;
2515                      $usercoursecontext = context_course::instance($usercourse->id);
2516                      $usercourseshortname = format_string($usercourse->shortname, true, array('context' => $usercoursecontext));
2517                      $usercoursenode = $userscoursesnode->add($usercourseshortname, new moodle_url('/user/view.php',
2518                              array('id' => $user->id, 'course' => $usercourse->id)), self::TYPE_CONTAINER);
2519  
2520                      $gradeavailable = has_capability('moodle/grade:view', $usercoursecontext);
2521                      if (!$gradeavailable && !empty($usercourse->showgrades) && is_array($reports) && !empty($reports)) {
2522                          foreach ($reports as $plugin => $plugindir) {
2523                              if (has_capability('gradereport/'.$plugin.':view', $usercoursecontext)) {
2524                                  // Stop when the first visible plugin is found.
2525                                  $gradeavailable = true;
2526                                  break;
2527                              }
2528                          }
2529                      }
2530  
2531                      if ($gradeavailable) {
2532                          $url = new moodle_url('/grade/report/index.php', array('id' => $usercourse->id));
2533                          $usercoursenode->add(get_string('grades'), $url, self::TYPE_SETTING, null, null,
2534                                  new pix_icon('i/grades', ''));
2535                      }
2536  
2537                      // Add a node to view the users notes if permitted.
2538                      if (!empty($CFG->enablenotes) &&
2539                              has_any_capability(array('moodle/notes:manage', 'moodle/notes:view'), $usercoursecontext)) {
2540                          $url = new moodle_url('/notes/index.php', array('user' => $user->id, 'course' => $usercourse->id));
2541                          $usercoursenode->add(get_string('notes', 'notes'), $url, self::TYPE_SETTING);
2542                      }
2543  
2544                      if (can_access_course($usercourse, $user->id, '', true)) {
2545                          $usercoursenode->add(get_string('entercourse'), new moodle_url('/course/view.php',
2546                                  array('id' => $usercourse->id)), self::TYPE_SETTING, null, null, new pix_icon('i/course', ''));
2547                      }
2548  
2549                      $reporttab = $usercoursenode->add(get_string('activityreports'));
2550  
2551                      $reportfunctions = get_plugin_list_with_function('report', 'extend_navigation_user', 'lib.php');
2552                      foreach ($reportfunctions as $reportfunction) {
2553                          $reportfunction($reporttab, $user, $usercourse);
2554                      }
2555  
2556                      $reporttab->trim_if_empty();
2557                  }
2558              }
2559  
2560              // Let plugins hook into user navigation.
2561              $pluginsfunction = get_plugins_with_function('extend_navigation_user', 'lib.php');
2562              foreach ($pluginsfunction as $plugintype => $plugins) {
2563                  if ($plugintype != 'report') {
2564                      foreach ($plugins as $pluginfunction) {
2565                          $pluginfunction($usernode, $user, $usercontext, $course, $coursecontext);
2566                      }
2567                  }
2568              }
2569          }
2570          return true;
2571      }
2572  
2573      /**
2574       * This method simply checks to see if a given module can extend the navigation.
2575       *
2576       * @todo (MDL-25290) A shared caching solution should be used to save details on what extends navigation.
2577       *
2578       * @param string $modname
2579       * @return bool
2580       */
2581      public static function module_extends_navigation($modname) {
2582          global $CFG;
2583          static $extendingmodules = array();
2584          if (!array_key_exists($modname, $extendingmodules)) {
2585              $extendingmodules[$modname] = false;
2586              $file = $CFG->dirroot.'/mod/'.$modname.'/lib.php';
2587              if (file_exists($file)) {
2588                  $function = $modname.'_extend_navigation';
2589                  require_once($file);
2590                  $extendingmodules[$modname] = (function_exists($function));
2591              }
2592          }
2593          return $extendingmodules[$modname];
2594      }
2595      /**
2596       * Extends the navigation for the given user.
2597       *
2598       * @param stdClass $user A user from the database
2599       */
2600      public function extend_for_user($user) {
2601          $this->extendforuser[] = $user;
2602      }
2603  
2604      /**
2605       * Returns all of the users the navigation is being extended for
2606       *
2607       * @return array An array of extending users.
2608       */
2609      public function get_extending_users() {
2610          return $this->extendforuser;
2611      }
2612      /**
2613       * Adds the given course to the navigation structure.
2614       *
2615       * @param stdClass $course
2616       * @param bool $forcegeneric
2617       * @param bool $ismycourse
2618       * @return navigation_node
2619       */
2620      public function add_course(stdClass $course, $forcegeneric = false, $coursetype = self::COURSE_OTHER) {
2621          global $CFG, $SITE;
2622  
2623          // We found the course... we can return it now :)
2624          if (!$forcegeneric && array_key_exists($course->id, $this->addedcourses)) {
2625              return $this->addedcourses[$course->id];
2626          }
2627  
2628          $coursecontext = context_course::instance($course->id);
2629  
2630          if ($coursetype != self::COURSE_MY && $coursetype != self::COURSE_CURRENT && $course->id != $SITE->id) {
2631              if (is_role_switched($course->id)) {
2632                  // user has to be able to access course in order to switch, let's skip the visibility test here
2633              } else if (!core_course_category::can_view_course_info($course)) {
2634                  return false;
2635              }
2636          }
2637  
2638          $issite = ($course->id == $SITE->id);
2639          $displaycontext = \context_helper::get_navigation_filter_context($coursecontext);
2640          $shortname = format_string($course->shortname, true, ['context' => $displaycontext]);
2641          $fullname = format_string($course->fullname, true, ['context' => $displaycontext]);
2642          // This is the name that will be shown for the course.
2643          $coursename = empty($CFG->navshowfullcoursenames) ? $shortname : $fullname;
2644  
2645          if ($coursetype == self::COURSE_CURRENT) {
2646              if ($coursenode = $this->rootnodes['mycourses']->find($course->id, self::TYPE_COURSE)) {
2647                  return $coursenode;
2648              } else {
2649                  $coursetype = self::COURSE_OTHER;
2650              }
2651          }
2652  
2653          // Can the user expand the course to see its content.
2654          $canexpandcourse = true;
2655          if ($issite) {
2656              $parent = $this;
2657              $url = null;
2658              if (empty($CFG->usesitenameforsitepages)) {
2659                  $coursename = get_string('sitepages');
2660              }
2661          } else if ($coursetype == self::COURSE_CURRENT) {
2662              $parent = $this->rootnodes['currentcourse'];
2663              $url = new moodle_url('/course/view.php', array('id'=>$course->id));
2664              $canexpandcourse = $this->can_expand_course($course);
2665          } else if ($coursetype == self::COURSE_MY && !$forcegeneric) {
2666              if (!empty($CFG->navshowmycoursecategories) && ($parent = $this->rootnodes['mycourses']->find($course->category, self::TYPE_MY_CATEGORY))) {
2667                  // Nothing to do here the above statement set $parent to the category within mycourses.
2668              } else {
2669                  $parent = $this->rootnodes['mycourses'];
2670              }
2671              $url = new moodle_url('/course/view.php', array('id'=>$course->id));
2672          } else {
2673              $parent = $this->rootnodes['courses'];
2674              $url = new moodle_url('/course/view.php', array('id'=>$course->id));
2675              // They can only expand the course if they can access it.
2676              $canexpandcourse = $this->can_expand_course($course);
2677              if (!empty($course->category) && $this->show_categories($coursetype == self::COURSE_MY)) {
2678                  if (!$this->is_category_fully_loaded($course->category)) {
2679                      // We need to load the category structure for this course
2680                      $this->load_all_categories($course->category, false);
2681                  }
2682                  if (array_key_exists($course->category, $this->addedcategories)) {
2683                      $parent = $this->addedcategories[$course->category];
2684                      // This could lead to the course being created so we should check whether it is the case again
2685                      if (!$forcegeneric && array_key_exists($course->id, $this->addedcourses)) {
2686                          return $this->addedcourses[$course->id];
2687                      }
2688                  }
2689              }
2690          }
2691  
2692          $coursenode = $parent->add($coursename, $url, self::TYPE_COURSE, $shortname, $course->id, new pix_icon('i/course', ''));
2693          $coursenode->showinflatnavigation = $coursetype == self::COURSE_MY;
2694  
2695          $coursenode->hidden = (!$course->visible);
2696          $coursenode->title(format_string($course->fullname, true, ['context' => $displaycontext, 'escape' => false]));
2697          if ($canexpandcourse) {
2698              // This course can be expanded by the user, make it a branch to make the system aware that its expandable by ajax.
2699              $coursenode->nodetype = self::NODETYPE_BRANCH;
2700              $coursenode->isexpandable = true;
2701          } else {
2702              $coursenode->nodetype = self::NODETYPE_LEAF;
2703              $coursenode->isexpandable = false;
2704          }
2705          if (!$forcegeneric) {
2706              $this->addedcourses[$course->id] = $coursenode;
2707          }
2708  
2709          return $coursenode;
2710      }
2711  
2712      /**
2713       * Returns a cache instance to use for the expand course cache.
2714       * @return cache_session
2715       */
2716      protected function get_expand_course_cache() {
2717          if ($this->cacheexpandcourse === null) {
2718              $this->cacheexpandcourse = cache::make('core', 'navigation_expandcourse');
2719          }
2720          return $this->cacheexpandcourse;
2721      }
2722  
2723      /**
2724       * Checks if a user can expand a course in the navigation.
2725       *
2726       * We use a cache here because in order to be accurate we need to call can_access_course which is a costly function.
2727       * Because this functionality is basic + non-essential and because we lack good event triggering this cache
2728       * permits stale data.
2729       * In the situation the user is granted access to a course after we've initialised this session cache the cache
2730       * will be stale.
2731       * It is brought up to date in only one of two ways.
2732       *   1. The user logs out and in again.
2733       *   2. The user browses to the course they've just being given access to.
2734       *
2735       * Really all this controls is whether the node is shown as expandable or not. It is uber un-important.
2736       *
2737       * @param stdClass $course
2738       * @return bool
2739       */
2740      protected function can_expand_course($course) {
2741          $cache = $this->get_expand_course_cache();
2742          $canexpand = $cache->get($course->id);
2743          if ($canexpand === false) {
2744              $canexpand = isloggedin() && can_access_course($course, null, '', true);
2745              $canexpand = (int)$canexpand;
2746              $cache->set($course->id, $canexpand);
2747          }
2748          return ($canexpand === 1);
2749      }
2750  
2751      /**
2752       * Returns true if the category has already been loaded as have any child categories
2753       *
2754       * @param int $categoryid
2755       * @return bool
2756       */
2757      protected function is_category_fully_loaded($categoryid) {
2758          return (array_key_exists($categoryid, $this->addedcategories) && ($this->allcategoriesloaded || $this->addedcategories[$categoryid]->children->count() > 0));
2759      }
2760  
2761      /**
2762       * Adds essential course nodes to the navigation for the given course.
2763       *
2764       * This method adds nodes such as reports, blogs and participants
2765       *
2766       * @param navigation_node $coursenode
2767       * @param stdClass $course
2768       * @return bool returns true on successful addition of a node.
2769       */
2770      public function add_course_essentials($coursenode, stdClass $course) {
2771          global $CFG, $SITE;
2772          require_once($CFG->dirroot . '/course/lib.php');
2773  
2774          if ($course->id == $SITE->id) {
2775              return $this->add_front_page_course_essentials($coursenode, $course);
2776          }
2777  
2778          if ($coursenode == false || !($coursenode instanceof navigation_node) || $coursenode->get('participants', navigation_node::TYPE_CONTAINER)) {
2779              return true;
2780          }
2781  
2782          $navoptions = course_get_user_navigation_options($this->page->context, $course);
2783  
2784          //Participants
2785          if ($navoptions->participants) {
2786              $participants = $coursenode->add(get_string('participants'), new moodle_url('/user/index.php?id='.$course->id),
2787                  self::TYPE_CONTAINER, get_string('participants'), 'participants', new pix_icon('i/users', ''));
2788  
2789              if ($navoptions->blogs) {
2790                  $blogsurls = new moodle_url('/blog/index.php');
2791                  if ($currentgroup = groups_get_course_group($course, true)) {
2792                      $blogsurls->param('groupid', $currentgroup);
2793                  } else {
2794                      $blogsurls->param('courseid', $course->id);
2795                  }
2796                  $participants->add(get_string('blogscourse', 'blog'), $blogsurls->out(), self::TYPE_SETTING, null, 'courseblogs');
2797              }
2798  
2799              if ($navoptions->notes) {
2800                  $participants->add(get_string('notes', 'notes'), new moodle_url('/notes/index.php', array('filtertype' => 'course', 'filterselect' => $course->id)), self::TYPE_SETTING, null, 'currentcoursenotes');
2801              }
2802          } else if (count($this->extendforuser) > 0) {
2803              $coursenode->add(get_string('participants'), null, self::TYPE_CONTAINER, get_string('participants'), 'participants');
2804          }
2805  
2806          // Badges.
2807          if ($navoptions->badges) {
2808              $url = new moodle_url('/badges/view.php', array('type' => 2, 'id' => $course->id));
2809  
2810              $coursenode->add(get_string('coursebadges', 'badges'), $url,
2811                      navigation_node::TYPE_SETTING, null, 'badgesview',
2812                      new pix_icon('i/badge', get_string('coursebadges', 'badges')));
2813          }
2814  
2815          // Check access to the course and competencies page.
2816          if ($navoptions->competencies) {
2817              // Just a link to course competency.
2818              $title = get_string('competencies', 'core_competency');
2819              $path = new moodle_url("/admin/tool/lp/coursecompetencies.php", array('courseid' => $course->id));
2820              $coursenode->add($title, $path, navigation_node::TYPE_SETTING, null, 'competencies',
2821                      new pix_icon('i/competencies', ''));
2822          }
2823          if ($navoptions->grades) {
2824              $url = new moodle_url('/grade/report/index.php', array('id'=>$course->id));
2825              $gradenode = $coursenode->add(get_string('grades'), $url, self::TYPE_SETTING, null,
2826                  'grades', new pix_icon('i/grades', ''));
2827              // If the page type matches the grade part, then make the nav drawer grade node (incl. all sub pages) active.
2828              if ($this->page->context->contextlevel < CONTEXT_MODULE && strpos($this->page->pagetype, 'grade-') === 0) {
2829                  $gradenode->make_active();
2830              }
2831          }
2832  
2833          return true;
2834      }
2835      /**
2836       * This generates the structure of the course that won't be generated when
2837       * the modules and sections are added.
2838       *
2839       * Things such as the reports branch, the participants branch, blogs... get
2840       * added to the course node by this method.
2841       *
2842       * @param navigation_node $coursenode
2843       * @param stdClass $course
2844       * @return bool True for successfull generation
2845       */
2846      public function add_front_page_course_essentials(navigation_node $coursenode, stdClass $course) {
2847          global $CFG, $USER, $COURSE, $SITE;
2848          require_once($CFG->dirroot . '/course/lib.php');
2849  
2850          if ($coursenode == false || $coursenode->get('frontpageloaded', navigation_node::TYPE_CUSTOM)) {
2851              return true;
2852          }
2853  
2854          $systemcontext = context_system::instance();
2855          $navoptions = course_get_user_navigation_options($systemcontext, $course);
2856  
2857          // Hidden node that we use to determine if the front page navigation is loaded.
2858          // This required as there are not other guaranteed nodes that may be loaded.
2859          $coursenode->add('frontpageloaded', null, self::TYPE_CUSTOM, null, 'frontpageloaded')->display = false;
2860  
2861          // Participants.
2862          if ($navoptions->participants) {
2863              $coursenode->add(get_string('participants'), new moodle_url('/user/index.php?id='.$course->id), self::TYPE_CUSTOM, get_string('participants'), 'participants');
2864          }
2865  
2866          // Blogs.
2867          if ($navoptions->blogs) {
2868              $blogsurls = new moodle_url('/blog/index.php');
2869              $coursenode->add(get_string('blogssite', 'blog'), $blogsurls->out(), self::TYPE_SYSTEM, null, 'siteblog');
2870          }
2871  
2872          $filterselect = 0;
2873  
2874          // Badges.
2875          if ($navoptions->badges) {
2876              $url = new moodle_url($CFG->wwwroot . '/badges/view.php', array('type' => 1));
2877              $coursenode->add(get_string('sitebadges', 'badges'), $url, navigation_node::TYPE_CUSTOM);
2878          }
2879  
2880          // Notes.
2881          if ($navoptions->notes) {
2882              $coursenode->add(get_string('notes', 'notes'), new moodle_url('/notes/index.php',
2883                  array('filtertype' => 'course', 'filterselect' => $filterselect)), self::TYPE_SETTING, null, 'notes');
2884          }
2885  
2886          // Tags
2887          if ($navoptions->tags) {
2888              $node = $coursenode->add(get_string('tags', 'tag'), new moodle_url('/tag/search.php'),
2889                      self::TYPE_SETTING, null, 'tags');
2890          }
2891  
2892          // Search.
2893          if ($navoptions->search) {
2894              $node = $coursenode->add(get_string('search', 'search'), new moodle_url('/search/index.php'),
2895                      self::TYPE_SETTING, null, 'search');
2896          }
2897  
2898          if ($navoptions->calendar) {
2899              $courseid = $COURSE->id;
2900              $params = array('view' => 'month');
2901              if ($courseid != $SITE->id) {
2902                  $params['course'] = $courseid;
2903              }
2904  
2905              // Calendar
2906              $calendarurl = new moodle_url('/calendar/view.php', $params);
2907              $node = $coursenode->add(get_string('calendar', 'calendar'), $calendarurl,
2908                  self::TYPE_CUSTOM, null, 'calendar', new pix_icon('i/calendar', ''));
2909              $node->showinflatnavigation = true;
2910          }
2911  
2912          if (isloggedin()) {
2913              $usercontext = context_user::instance($USER->id);
2914              if (has_capability('moodle/user:manageownfiles', $usercontext)) {
2915                  $url = new moodle_url('/user/files.php');
2916                  $node = $coursenode->add(get_string('privatefiles'), $url,
2917                      self::TYPE_SETTING, null, 'privatefiles', new pix_icon('i/privatefiles', ''));
2918                  $node->display = false;
2919                  $node->showinflatnavigation = true;
2920                  $node->mainnavonly = true;
2921              }
2922          }
2923  
2924          if (isloggedin()) {
2925              $context = $this->page->context;
2926              switch ($context->contextlevel) {
2927                  case CONTEXT_COURSECAT:
2928                      // OK, expected context level.
2929                      break;
2930                  case CONTEXT_COURSE:
2931                      // OK, expected context level if not on frontpage.
2932                      if ($COURSE->id != $SITE->id) {
2933                          break;
2934                      }
2935                  default:
2936                      // If this context is part of a course (excluding frontpage), use the course context.
2937                      // Otherwise, use the system context.
2938                      $coursecontext = $context->get_course_context(false);
2939                      if ($coursecontext && $coursecontext->instanceid !== $SITE->id) {
2940                          $context = $coursecontext;
2941                      } else {
2942                          $context = $systemcontext;
2943                      }
2944              }
2945  
2946              $params = ['contextid' => $context->id];
2947              if (has_capability('moodle/contentbank:access', $context)) {
2948                  $url = new moodle_url('/contentbank/index.php', $params);
2949                  $node = $coursenode->add(get_string('contentbank'), $url,
2950                      self::TYPE_CUSTOM, null, 'contentbank', new pix_icon('i/contentbank', ''));
2951                  $node->showinflatnavigation = true;
2952              }
2953          }
2954  
2955          return true;
2956      }
2957  
2958      /**
2959       * Clears the navigation cache
2960       */
2961      public function clear_cache() {
2962          $this->cache->clear();
2963      }
2964  
2965      /**
2966       * Sets an expansion limit for the navigation
2967       *
2968       * The expansion limit is used to prevent the display of content that has a type
2969       * greater than the provided $type.
2970       *
2971       * Can be used to ensure things such as activities or activity content don't get
2972       * shown on the navigation.
2973       * They are still generated in order to ensure the navbar still makes sense.
2974       *
2975       * @param int $type One of navigation_node::TYPE_*
2976       * @return bool true when complete.
2977       */
2978      public function set_expansion_limit($type) {
2979          global $SITE;
2980          $nodes = $this->find_all_of_type($type);
2981  
2982          // We only want to hide specific types of nodes.
2983          // Only nodes that represent "structure" in the navigation tree should be hidden.
2984          // If we hide all nodes then we risk hiding vital information.
2985          $typestohide = array(
2986              self::TYPE_CATEGORY,
2987              self::TYPE_COURSE,
2988              self::TYPE_SECTION,
2989              self::TYPE_ACTIVITY
2990          );
2991  
2992          foreach ($nodes as $node) {
2993              // We need to generate the full site node
2994              if ($type == self::TYPE_COURSE && $node->key == $SITE->id) {
2995                  continue;
2996              }
2997              foreach ($node->children as $child) {
2998                  $child->hide($typestohide);
2999              }
3000          }
3001          return true;
3002      }
3003      /**
3004       * Attempts to get the navigation with the given key from this nodes children.
3005       *
3006       * This function only looks at this nodes children, it does NOT look recursivily.
3007       * If the node can't be found then false is returned.
3008       *
3009       * If you need to search recursivily then use the {@link global_navigation::find()} method.
3010       *
3011       * Note: If you are trying to set the active node {@link navigation_node::override_active_url()}
3012       * may be of more use to you.
3013       *
3014       * @param string|int $key The key of the node you wish to receive.
3015       * @param int $type One of navigation_node::TYPE_*
3016       * @return navigation_node|false
3017       */
3018      public function get($key, $type = null) {
3019          if (!$this->initialised) {
3020              $this->initialise();
3021          }
3022          return parent::get($key, $type);
3023      }
3024  
3025      /**
3026       * Searches this nodes children and their children to find a navigation node
3027       * with the matching key and type.
3028       *
3029       * This method is recursive and searches children so until either a node is
3030       * found or there are no more nodes to search.
3031       *
3032       * If you know that the node being searched for is a child of this node
3033       * then use the {@link global_navigation::get()} method instead.
3034       *
3035       * Note: If you are trying to set the active node {@link navigation_node::override_active_url()}
3036       * may be of more use to you.
3037       *
3038       * @param string|int $key The key of the node you wish to receive.
3039       * @param int $type One of navigation_node::TYPE_*
3040       * @return navigation_node|false
3041       */
3042      public function find($key, $type) {
3043          if (!$this->initialised) {
3044              $this->initialise();
3045          }
3046          if ($type == self::TYPE_ROOTNODE && array_key_exists($key, $this->rootnodes)) {
3047              return $this->rootnodes[$key];
3048          }
3049          return parent::find($key, $type);
3050      }
3051  
3052      /**
3053       * They've expanded the 'my courses' branch.
3054       */
3055      protected function load_courses_enrolled() {
3056          global $CFG;
3057  
3058          $limit = (int) $CFG->navcourselimit;
3059  
3060          $courses = enrol_get_my_courses('*');
3061          $flatnavcourses = [];
3062  
3063          // Go through the courses and see which ones we want to display in the flatnav.
3064          foreach ($courses as $course) {
3065              $classify = course_classify_for_timeline($course);
3066  
3067              if ($classify == COURSE_TIMELINE_INPROGRESS) {
3068                  $flatnavcourses[$course->id] = $course;
3069              }
3070          }
3071  
3072          // Get the number of courses that can be displayed in the nav block and in the flatnav.
3073          $numtotalcourses = count($courses);
3074          $numtotalflatnavcourses = count($flatnavcourses);
3075  
3076          // Reduce the size of the arrays to abide by the 'navcourselimit' setting.
3077          $courses = array_slice($courses, 0, $limit, true);
3078          $flatnavcourses = array_slice($flatnavcourses, 0, $limit, true);
3079  
3080          // Get the number of courses we are going to show for each.
3081          $numshowncourses = count($courses);
3082          $numshownflatnavcourses = count($flatnavcourses);
3083          if ($numshowncourses && $this->show_my_categories()) {
3084              // Generate an array containing unique values of all the courses' categories.
3085              $categoryids = array();
3086              foreach ($courses as $course) {
3087                  if (in_array($course->category, $categoryids)) {
3088                      continue;
3089                  }
3090                  $categoryids[] = $course->category;
3091              }
3092  
3093              // Array of category IDs that include the categories of the user's courses and the related course categories.
3094              $fullpathcategoryids = [];
3095              // Get the course categories for the enrolled courses' category IDs.
3096              $mycoursecategories = core_course_category::get_many($categoryids);
3097              // Loop over each of these categories and build the category tree using each category's path.
3098              foreach ($mycoursecategories as $mycoursecat) {
3099                  $pathcategoryids = explode('/', $mycoursecat->path);
3100                  // First element of the exploded path is empty since paths begin with '/'.
3101                  array_shift($pathcategoryids);
3102                  // Merge the exploded category IDs into the full list of category IDs that we will fetch.
3103                  $fullpathcategoryids = array_merge($fullpathcategoryids, $pathcategoryids);
3104              }
3105  
3106              // Fetch all of the categories related to the user's courses.
3107              $pathcategories = core_course_category::get_many($fullpathcategoryids);
3108              // Loop over each of these categories and build the category tree.
3109              foreach ($pathcategories as $coursecat) {
3110                  // No need to process categories that have already been added.
3111                  if (isset($this->addedcategories[$coursecat->id])) {
3112                      continue;
3113                  }
3114                  // Skip categories that are not visible.
3115                  if (!$coursecat->is_uservisible()) {
3116                      continue;
3117                  }
3118  
3119                  // Get this course category's parent node.
3120                  $parent = null;
3121                  if ($coursecat->parent && isset($this->addedcategories[$coursecat->parent])) {
3122                      $parent = $this->addedcategories[$coursecat->parent];
3123                  }
3124                  if (!$parent) {
3125                      // If it has no parent, then it should be right under the My courses node.
3126                      $parent = $this->rootnodes['mycourses'];
3127                  }
3128  
3129                  // Build the category object based from the coursecat object.
3130                  $mycategory = new stdClass();
3131                  $mycategory->id = $coursecat->id;
3132                  $mycategory->name = $coursecat->name;
3133                  $mycategory->visible = $coursecat->visible;
3134  
3135                  // Add this category to the nav tree.
3136                  $this->add_category($mycategory, $parent, self::TYPE_MY_CATEGORY);
3137              }
3138          }
3139  
3140          // Go through each course now and add it to the nav block, and the flatnav if applicable.
3141          foreach ($courses as $course) {
3142              $node = $this->add_course($course, false, self::COURSE_MY);
3143              if ($node) {
3144                  $node->showinflatnavigation = false;
3145                  // Check if we should also add this to the flat nav as well.
3146                  if (isset($flatnavcourses[$course->id])) {
3147                      $node->showinflatnavigation = true;
3148                  }
3149              }
3150          }
3151  
3152          // Go through each course in the flatnav now.
3153          foreach ($flatnavcourses as $course) {
3154              // Check if we haven't already added it.
3155              if (!isset($courses[$course->id])) {
3156                  // Ok, add it to the flatnav only.
3157                  $node = $this->add_course($course, false, self::COURSE_MY);
3158                  $node->display = false;
3159                  $node->showinflatnavigation = true;
3160              }
3161          }
3162  
3163          $showmorelinkinnav = $numtotalcourses > $numshowncourses;
3164          $showmorelinkinflatnav = $numtotalflatnavcourses > $numshownflatnavcourses;
3165          // Show a link to the course page if there are more courses the user is enrolled in.
3166          if ($showmorelinkinnav || $showmorelinkinflatnav) {
3167              // Adding hash to URL so the link is not highlighted in the navigation when clicked.
3168              $url = new moodle_url('/my/');
3169              $parent = $this->rootnodes['mycourses'];
3170              $coursenode = $parent->add(get_string('morenavigationlinks'), $url, self::TYPE_CUSTOM, null, self::COURSE_INDEX_PAGE);
3171  
3172              if ($showmorelinkinnav) {
3173                  $coursenode->display = true;
3174              }
3175  
3176              if ($showmorelinkinflatnav) {
3177                  $coursenode->showinflatnavigation = true;
3178              }
3179          }
3180      }
3181  }
3182  
3183  /**
3184   * The global navigation class used especially for AJAX requests.
3185   *
3186   * The primary methods that are used in the global navigation class have been overriden
3187   * to ensure that only the relevant branch is generated at the root of the tree.
3188   * This can be done because AJAX is only used when the backwards structure for the
3189   * requested branch exists.
3190   * This has been done only because it shortens the amounts of information that is generated
3191   * which of course will speed up the response time.. because no one likes laggy AJAX.
3192   *
3193   * @package   core
3194   * @category  navigation
3195   * @copyright 2009 Sam Hemelryk
3196   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3197   */
3198  class global_navigation_for_ajax extends global_navigation {
3199  
3200      /** @var int used for determining what type of navigation_node::TYPE_* is being used */
3201      protected $branchtype;
3202  
3203      /** @var int the instance id */
3204      protected $instanceid;
3205  
3206      /** @var array Holds an array of expandable nodes */
3207      protected $expandable = array();
3208  
3209      /**
3210       * Constructs the navigation for use in an AJAX request
3211       *
3212       * @param moodle_page $page moodle_page object
3213       * @param int $branchtype
3214       * @param int $id
3215       */
3216      public function __construct($page, $branchtype, $id) {
3217          $this->page = $page;
3218          $this->cache = new navigation_cache(NAVIGATION_CACHE_NAME);
3219          $this->children = new navigation_node_collection();
3220          $this->branchtype = $branchtype;
3221          $this->instanceid = $id;
3222          $this->initialise();
3223      }
3224      /**
3225       * Initialise the navigation given the type and id for the branch to expand.
3226       *
3227       * @return array An array of the expandable nodes
3228       */
3229      public function initialise() {
3230          global $DB, $SITE;
3231  
3232          if ($this->initialised || during_initial_install()) {
3233              return $this->expandable;
3234          }
3235          $this->initialised = true;
3236  
3237          $this->rootnodes = array();
3238          $this->rootnodes['site']    = $this->add_course($SITE);
3239          $this->rootnodes['mycourses'] = $this->add(get_string('mycourses'), new moodle_url('/my'), self::TYPE_ROOTNODE, null, 'mycourses');
3240          $this->rootnodes['courses'] = $this->add(get_string('courses'), null, self::TYPE_ROOTNODE, null, 'courses');
3241          // The courses branch is always displayed, and is always expandable (although may be empty).
3242          // This mimicks what is done during {@link global_navigation::initialise()}.
3243          $this->rootnodes['courses']->isexpandable = true;
3244  
3245          // Branchtype will be one of navigation_node::TYPE_*
3246          switch ($this->branchtype) {
3247              case 0:
3248                  if ($this->instanceid === 'mycourses') {
3249                      $this->load_courses_enrolled();
3250                  } else if ($this->instanceid === 'courses') {
3251                      $this->load_courses_other();
3252                  }
3253                  break;
3254              case self::TYPE_CATEGORY :
3255                  $this->load_category($this->instanceid);
3256                  break;
3257              case self::TYPE_MY_CATEGORY :
3258                  $this->load_category($this->instanceid, self::TYPE_MY_CATEGORY);
3259                  break;
3260              case self::TYPE_COURSE :
3261                  $course = $DB->get_record('course', array('id' => $this->instanceid), '*', MUST_EXIST);
3262                  if (!can_access_course($course, null, '', true)) {
3263                      // Thats OK all courses are expandable by default. We don't need to actually expand it we can just
3264                      // add the course node and break. This leads to an empty node.
3265                      $this->add_course($course);
3266                      break;
3267                  }
3268                  require_course_login($course, true, null, false, true);
3269                  $this->page->set_context(context_course::instance($course->id));
3270                  $coursenode = $this->add_course($course, false, self::COURSE_CURRENT);
3271                  $this->add_course_essentials($coursenode, $course);
3272                  $this->load_course_sections($course, $coursenode);
3273                  break;
3274              case self::TYPE_SECTION :
3275                  $sql = 'SELECT c.*, cs.section AS sectionnumber
3276                          FROM {course} c
3277                          LEFT JOIN {course_sections} cs ON cs.course = c.id
3278                          WHERE cs.id = ?';
3279                  $course = $DB->get_record_sql($sql, array($this->instanceid), MUST_EXIST);
3280                  require_course_login($course, true, null, false, true);
3281                  $this->page->set_context(context_course::instance($course->id));
3282                  $coursenode = $this->add_course($course, false, self::COURSE_CURRENT);
3283                  $this->add_course_essentials($coursenode, $course);
3284                  $this->load_course_sections($course, $coursenode, $course->sectionnumber);
3285                  break;
3286              case self::TYPE_ACTIVITY :
3287                  $sql = "SELECT c.*
3288                            FROM {course} c
3289                            JOIN {course_modules} cm ON cm.course = c.id
3290                           WHERE cm.id = :cmid";
3291                  $params = array('cmid' => $this->instanceid);
3292                  $course = $DB->get_record_sql($sql, $params, MUST_EXIST);
3293                  $modinfo = get_fast_modinfo($course);
3294                  $cm = $modinfo->get_cm($this->instanceid);
3295                  require_course_login($course, true, $cm, false, true);
3296                  $this->page->set_context(context_module::instance($cm->id));
3297                  $coursenode = $this->add_course($course, false, self::COURSE_CURRENT);
3298                  $this->load_course_sections($course, $coursenode, null, $cm);
3299                  $activitynode = $coursenode->find($cm->id, self::TYPE_ACTIVITY);
3300                  if ($activitynode) {
3301                      $modulenode = $this->load_activity($cm, $course, $activitynode);
3302                  }
3303                  break;
3304              default:
3305                  throw new Exception('Unknown type');
3306                  return $this->expandable;
3307          }
3308  
3309          if ($this->page->context->contextlevel == CONTEXT_COURSE && $this->page->context->instanceid != $SITE->id) {
3310              $this->load_for_user(null, true);
3311          }
3312  
3313          // Give the local plugins a chance to include some navigation if they want.
3314          $this->load_local_plugin_navigation();
3315  
3316          $this->find_expandable($this->expandable);
3317          return $this->expandable;
3318      }
3319  
3320      /**
3321       * They've expanded the general 'courses' branch.
3322       */
3323      protected function load_courses_other() {
3324          $this->load_all_courses();
3325      }
3326  
3327      /**
3328       * Loads a single category into the AJAX navigation.
3329       *
3330       * This function is special in that it doesn't concern itself with the parent of
3331       * the requested category or its siblings.
3332       * This is because with the AJAX navigation we know exactly what is wanted and only need to
3333       * request that.
3334       *
3335       * @global moodle_database $DB
3336       * @param int $categoryid id of category to load in navigation.
3337       * @param int $nodetype type of node, if category is under MyHome then it's TYPE_MY_CATEGORY
3338       * @return void.
3339       */
3340      protected function load_category($categoryid, $nodetype = self::TYPE_CATEGORY) {
3341          global $CFG, $DB;
3342  
3343          $limit = 20;
3344          if (!empty($CFG->navcourselimit)) {
3345              $limit = (int)$CFG->navcourselimit;
3346          }
3347  
3348          $catcontextsql = context_helper::get_preload_record_columns_sql('ctx');
3349          $sql = "SELECT cc.*, $catcontextsql
3350                    FROM {course_categories} cc
3351                    JOIN {context} ctx ON cc.id = ctx.instanceid
3352                   WHERE ctx.contextlevel = ".CONTEXT_COURSECAT." AND
3353                         (cc.id = :categoryid1 OR cc.parent = :categoryid2)
3354                ORDER BY cc.depth ASC, cc.sortorder ASC, cc.id ASC";
3355          $params = array('categoryid1' => $categoryid, 'categoryid2' => $categoryid);
3356          $categories = $DB->get_recordset_sql($sql, $params, 0, $limit);
3357          $categorylist = array();
3358          $subcategories = array();
3359          $basecategory = null;
3360          foreach ($categories as $category) {
3361              $categorylist[] = $category->id;
3362              context_helper::preload_from_record($category);
3363              if ($category->id == $categoryid) {
3364                  $this->add_category($category, $this, $nodetype);
3365                  $basecategory = $this->addedcategories[$category->id];
3366              } else {
3367                  $subcategories[$category->id] = $category;
3368              }
3369          }
3370          $categories->close();
3371  
3372  
3373          // If category is shown in MyHome then only show enrolled courses and hide empty subcategories,
3374          // else show all courses.
3375          if ($nodetype === self::TYPE_MY_CATEGORY) {
3376              $courses = enrol_get_my_courses('*');
3377              $categoryids = array();
3378  
3379              // Only search for categories if basecategory was found.
3380              if (!is_null($basecategory)) {
3381                  // Get course parent category ids.
3382                  foreach ($courses as $course) {
3383                      $categoryids[] = $course->category;
3384                  }
3385  
3386                  // Get a unique list of category ids which a part of the path
3387                  // to user's courses.
3388                  $coursesubcategories = array();
3389                  $addedsubcategories = array();
3390  
3391                  list($sql, $params) = $DB->get_in_or_equal($categoryids);
3392                  $categories = $DB->get_recordset_select('course_categories', 'id '.$sql, $params, 'sortorder, id', 'id, path');
3393  
3394                  foreach ($categories as $category){
3395                      $coursesubcategories = array_merge($coursesubcategories, explode('/', trim($category->path, "/")));
3396                  }
3397                  $categories->close();
3398                  $coursesubcategories = array_unique($coursesubcategories);
3399  
3400                  // Only add a subcategory if it is part of the path to user's course and
3401                  // wasn't already added.
3402                  foreach ($subcategories as $subid => $subcategory) {
3403                      if (in_array($subid, $coursesubcategories) &&
3404                              !in_array($subid, $addedsubcategories)) {
3405                              $this->add_category($subcategory, $basecategory, $nodetype);
3406                              $addedsubcategories[] = $subid;
3407                      }
3408                  }
3409              }
3410  
3411              foreach ($courses as $course) {
3412                  // Add course if it's in category.
3413                  if (in_array($course->category, $categorylist)) {
3414                      $this->add_course($course, true, self::COURSE_MY);
3415                  }
3416              }
3417          } else {
3418              if (!is_null($basecategory)) {
3419                  foreach ($subcategories as $key=>$category) {
3420                      $this->add_category($category, $basecategory, $nodetype);
3421                  }
3422              }
3423              $courses = $DB->get_recordset('course', array('category' => $categoryid), 'sortorder', '*' , 0, $limit);
3424              foreach ($courses as $course) {
3425                  $this->add_course($course);
3426              }
3427              $courses->close();
3428          }
3429      }
3430  
3431      /**
3432       * Returns an array of expandable nodes
3433       * @return array
3434       */
3435      public function get_expandable() {
3436          return $this->expandable;
3437      }
3438  }
3439  
3440  /**
3441   * Navbar class
3442   *
3443   * This class is used to manage the navbar, which is initialised from the navigation
3444   * object held by PAGE
3445   *
3446   * @package   core
3447   * @category  navigation
3448   * @copyright 2009 Sam Hemelryk
3449   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3450   */
3451  class navbar extends navigation_node {
3452      /** @var bool A switch for whether the navbar is initialised or not */
3453      protected $initialised = false;
3454      /** @var mixed keys used to reference the nodes on the navbar */
3455      protected $keys = array();
3456      /** @var null|string content of the navbar */
3457      protected $content = null;
3458      /** @var moodle_page object the moodle page that this navbar belongs to */
3459      protected $page;
3460      /** @var bool A switch for whether to ignore the active navigation information */
3461      protected $ignoreactive = false;
3462      /** @var bool A switch to let us know if we are in the middle of an install */
3463      protected $duringinstall = false;
3464      /** @var bool A switch for whether the navbar has items */
3465      protected $hasitems = false;
3466      /** @var array An array of navigation nodes for the navbar */
3467      protected $items;
3468      /** @var array An array of child node objects */
3469      public $children = array();
3470      /** @var bool A switch for whether we want to include the root node in the navbar */
3471      public $includesettingsbase = false;
3472      /** @var breadcrumb_navigation_node[] $prependchildren */
3473      protected $prependchildren = array();
3474  
3475      /**
3476       * The almighty constructor
3477       *
3478       * @param moodle_page $page
3479       */
3480      public function __construct(moodle_page $page) {
3481          global $CFG;
3482          if (during_initial_install()) {
3483              $this->duringinstall = true;
3484              return false;
3485          }
3486          $this->page = $page;
3487          $this->text = get_string('home');
3488          $this->shorttext = get_string('home');
3489          $this->action = new moodle_url($CFG->wwwroot);
3490          $this->nodetype = self::NODETYPE_BRANCH;
3491          $this->type = self::TYPE_SYSTEM;
3492      }
3493  
3494      /**
3495       * Quick check to see if the navbar will have items in.
3496       *
3497       * @return bool Returns true if the navbar will have items, false otherwise
3498       */
3499      public function has_items() {
3500          if ($this->duringinstall) {
3501              return false;
3502          } else if ($this->hasitems !== false) {
3503              return true;
3504          }
3505          if (count($this->children) > 0 || count($this->prependchildren) > 0) {
3506              // There have been manually added items - there are definitely items.
3507              $outcome = true;
3508          } else if (!$this->ignoreactive) {
3509              // We will need to initialise the navigation structure to check if there are active items.
3510              $this->page->navigation->initialise($this->page);
3511              $outcome = ($this->page->navigation->contains_active_node() || $this->page->settingsnav->contains_active_node());
3512          }
3513          $this->hasitems = $outcome;
3514          return $outcome;
3515      }
3516  
3517      /**
3518       * Turn on/off ignore active
3519       *
3520       * @param bool $setting
3521       */
3522      public function ignore_active($setting=true) {
3523          $this->ignoreactive = ($setting);
3524      }
3525  
3526      /**
3527       * Gets a navigation node
3528       *
3529       * @param string|int $key for referencing the navbar nodes
3530       * @param int $type breadcrumb_navigation_node::TYPE_*
3531       * @return breadcrumb_navigation_node|bool
3532       */
3533      public function get($key, $type = null) {
3534          foreach ($this->children as &$child) {
3535              if ($child->key === $key && ($type == null || $type == $child->type)) {
3536                  return $child;
3537              }
3538          }
3539          foreach ($this->prependchildren as &$child) {
3540              if ($child->key === $key && ($type == null || $type == $child->type)) {
3541                  return $child;
3542              }
3543          }
3544          return false;
3545      }
3546      /**
3547       * Returns an array of breadcrumb_navigation_nodes that make up the navbar.
3548       *
3549       * @return array
3550       */
3551      public function get_items() {
3552          global $CFG;
3553          $items = array();
3554          // Make sure that navigation is initialised
3555          if (!$this->has_items()) {
3556              return $items;
3557          }
3558          if ($this->items !== null) {
3559              return $this->items;
3560          }
3561  
3562          if (count($this->children) > 0) {
3563              // Add the custom children.
3564              $items = array_reverse($this->children);
3565          }
3566  
3567          // Check if navigation contains the active node
3568          if (!$this->ignoreactive) {
3569              // We will need to ensure the navigation has been initialised.
3570              $this->page->navigation->initialise($this->page);
3571              // Now find the active nodes on both the navigation and settings.
3572              $navigationactivenode = $this->page->navigation->find_active_node();
3573              $settingsactivenode = $this->page->settingsnav->find_active_node();
3574  
3575              if ($navigationactivenode && $settingsactivenode) {
3576                  // Parse a combined navigation tree
3577                  while ($settingsactivenode && $settingsactivenode->parent !== null) {
3578                      if (!$settingsactivenode->mainnavonly) {
3579                          $items[] = new breadcrumb_navigation_node($settingsactivenode);
3580                      }
3581                      $settingsactivenode = $settingsactivenode->parent;
3582                  }
3583                  if (!$this->includesettingsbase) {
3584                      // Removes the first node from the settings (root node) from the list
3585                      array_pop($items);
3586                  }
3587                  while ($navigationactivenode && $navigationactivenode->parent !== null) {
3588                      if (!$navigationactivenode->mainnavonly) {
3589                          $items[] = new breadcrumb_navigation_node($navigationactivenode);
3590                      }
3591                      if (!empty($CFG->navshowcategories) &&
3592                              $navigationactivenode->type === self::TYPE_COURSE &&
3593                              $navigationactivenode->parent->key === 'currentcourse') {
3594                          foreach ($this->get_course_categories() as $item) {
3595                              $items[] = new breadcrumb_navigation_node($item);
3596                          }
3597                      }
3598                      $navigationactivenode = $navigationactivenode->parent;
3599                  }
3600              } else if ($navigationactivenode) {
3601                  // Parse the navigation tree to get the active node
3602                  while ($navigationactivenode && $navigationactivenode->parent !== null) {
3603                      if (!$navigationactivenode->mainnavonly) {
3604                          $items[] = new breadcrumb_navigation_node($navigationactivenode);
3605                      }
3606                      if (!empty($CFG->navshowcategories) &&
3607                              $navigationactivenode->type === self::TYPE_COURSE &&
3608                              $navigationactivenode->parent->key === 'currentcourse') {
3609                          foreach ($this->get_course_categories() as $item) {
3610                              $items[] = new breadcrumb_navigation_node($item);
3611                          }
3612                      }
3613                      $navigationactivenode = $navigationactivenode->parent;
3614                  }
3615              } else if ($settingsactivenode) {
3616                  // Parse the settings navigation to get the active node
3617                  while ($settingsactivenode && $settingsactivenode->parent !== null) {
3618                      if (!$settingsactivenode->mainnavonly) {
3619                          $items[] = new breadcrumb_navigation_node($settingsactivenode);
3620                      }
3621                      $settingsactivenode = $settingsactivenode->parent;
3622                  }
3623              }
3624          }
3625  
3626          $items[] = new breadcrumb_navigation_node(array(
3627              'text' => $this->page->navigation->text,
3628              'shorttext' => $this->page->navigation->shorttext,
3629              'key' => $this->page->navigation->key,
3630              'action' => $this->page->navigation->action
3631          ));
3632  
3633          if (count($this->prependchildren) > 0) {
3634              // Add the custom children
3635              $items = array_merge($items, array_reverse($this->prependchildren));
3636          }
3637  
3638          $last = reset($items);
3639          if ($last) {
3640              $last->set_last(true);
3641          }
3642          $this->items = array_reverse($items);
3643          return $this->items;
3644      }
3645  
3646      /**
3647       * Get the list of categories leading to this course.
3648       *
3649       * This function is used by {@link navbar::get_items()} to add back the "courses"
3650       * node and category chain leading to the current course.  Note that this is only ever
3651       * called for the current course, so we don't need to bother taking in any parameters.
3652       *
3653       * @return array
3654       */
3655      private function get_course_categories() {
3656          global $CFG;
3657          require_once($CFG->dirroot.'/course/lib.php');
3658  
3659          $categories = array();
3660          $cap = 'moodle/category:viewhiddencategories';
3661          $showcategories = !core_course_category::is_simple_site();
3662  
3663          if ($showcategories) {
3664              foreach ($this->page->categories as $category) {
3665                  $context = context_coursecat::instance($category->id);
3666                  if (!core_course_category::can_view_category($category)) {
3667                      continue;
3668                  }
3669  
3670                  $displaycontext = \context_helper::get_navigation_filter_context($context);
3671                  $url = new moodle_url('/course/index.php', ['categoryid' => $category->id]);
3672                  $name = format_string($category->name, true, ['context' => $displaycontext]);
3673                  $categorynode = breadcrumb_navigation_node::create($name, $url, self::TYPE_CATEGORY, null, $category->id);
3674                  if (!$category->visible) {
3675                      $categorynode->hidden = true;
3676                  }
3677                  $categories[] = $categorynode;
3678              }
3679          }
3680  
3681          // Don't show the 'course' node if enrolled in this course.
3682          $coursecontext = context_course::instance($this->page->course->id);
3683          if (!is_enrolled($coursecontext, null, '', true)) {
3684              $courses = $this->page->navigation->get('courses');
3685              if (!$courses) {
3686                  // Courses node may not be present.
3687                  $courses = breadcrumb_navigation_node::create(
3688                      get_string('courses'),
3689                      new moodle_url('/course/index.php'),
3690                      self::TYPE_CONTAINER
3691                  );
3692              }
3693              $categories[] = $courses;
3694          }
3695  
3696          return $categories;
3697      }
3698  
3699      /**
3700       * Add a new breadcrumb_navigation_node to the navbar, overrides parent::add
3701       *
3702       * This function overrides {@link breadcrumb_navigation_node::add()} so that we can change
3703       * the way nodes get added to allow us to simply call add and have the node added to the
3704       * end of the navbar
3705       *
3706       * @param string $text
3707       * @param string|moodle_url|action_link $action An action to associate with this node.
3708       * @param int $type One of navigation_node::TYPE_*
3709       * @param string $shorttext
3710       * @param string|int $key A key to identify this node with. Key + type is unique to a parent.
3711       * @param pix_icon $icon An optional icon to use for this node.
3712       * @return navigation_node
3713       */
3714      public function add($text, $action=null, $type=self::TYPE_CUSTOM, $shorttext=null, $key=null, pix_icon $icon=null) {
3715          if ($this->content !== null) {
3716              debugging('Nav bar items must be printed before $OUTPUT->header() has been called', DEBUG_DEVELOPER);
3717          }
3718  
3719          // Properties array used when creating the new navigation node
3720          $itemarray = array(
3721              'text' => $text,
3722              'type' => $type
3723          );
3724          // Set the action if one was provided
3725          if ($action!==null) {
3726              $itemarray['action'] = $action;
3727          }
3728          // Set the shorttext if one was provided
3729          if ($shorttext!==null) {
3730              $itemarray['shorttext'] = $shorttext;
3731          }
3732          // Set the icon if one was provided
3733          if ($icon!==null) {
3734              $itemarray['icon'] = $icon;
3735          }
3736          // Default the key to the number of children if not provided
3737          if ($key === null) {
3738              $key = count($this->children);
3739          }
3740          // Set the key
3741          $itemarray['key'] = $key;
3742          // Set the parent to this node
3743          $itemarray['parent'] = $this;
3744          // Add the child using the navigation_node_collections add method
3745          $this->children[] = new breadcrumb_navigation_node($itemarray);
3746          return $this;
3747      }
3748  
3749      /**
3750       * Prepends a new navigation_node to the start of the navbar
3751       *
3752       * @param string $text
3753       * @param string|moodle_url|action_link $action An action to associate with this node.
3754       * @param int $type One of navigation_node::TYPE_*
3755       * @param string $shorttext
3756       * @param string|int $key A key to identify this node with. Key + type is unique to a parent.
3757       * @param pix_icon $icon An optional icon to use for this node.
3758       * @return navigation_node
3759       */
3760      public function prepend($text, $action=null, $type=self::TYPE_CUSTOM, $shorttext=null, $key=null, pix_icon $icon=null) {
3761          if ($this->content !== null) {
3762