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   1  YUI.add('moodle-core-actionmenu', function (Y, NAME) {
   2  
   3  /**
   4   * Provides drop down menus for list of action links.
   5   *
   6   * @module moodle-core-actionmenu
   7   */
   8  
   9  var BODY = Y.one(Y.config.doc.body),
  10      CSS = {
  11          MENUSHOWN : 'action-menu-shown'
  12      },
  13      SELECTOR = {
  14          CAN_RECEIVE_FOCUS_SELECTOR: 'input:not([type="hidden"]), a[href], button, textarea, select, [tabindex]',
  15          MENU : '.moodle-actionmenu[data-enhance=moodle-core-actionmenu]',
  16          MENUBAR: '[role="menubar"]',
  17          MENUITEM: '[role="menuitem"]',
  18          MENUCONTENT : '.menu[data-rel=menu-content]',
  19          MENUCONTENTCHILD: 'li a',
  20          MENUCHILD: '.menu li a',
  21          TOGGLE : '.toggle-display',
  22          KEEPOPEN: '[data-keepopen="1"]',
  23          MENUBARITEMS: [
  24              '[role="menubar"] > [role="menuitem"]',
  25              '[role="menubar"] > [role="presentation"] > [role="menuitem"]'
  26          ],
  27          MENUITEMS: [
  28              '> [role="menuitem"]',
  29              '> [role="presentation"] > [role="menuitem"]'
  30          ]
  31      },
  32      ACTIONMENU,
  33      ALIGN = {
  34          TL : 'tl',
  35          TR : 'tr',
  36          BL : 'bl',
  37          BR : 'br'
  38      };
  39  
  40  /**
  41   * Action menu support.
  42   * This converts a generic list of links into a drop down menu opened by hovering or clicking
  43   * on a menu icon.
  44   *
  45   * @namespace M.core.actionmenu
  46   * @class ActionMenu
  47   * @constructor
  48   * @extends Base
  49   */
  50  ACTIONMENU = function() {
  51      ACTIONMENU.superclass.constructor.apply(this, arguments);
  52  };
  53  ACTIONMENU.prototype = {
  54  
  55      /**
  56       * The dialogue used for all action menu displays.
  57       * @property type
  58       * @type M.core.dialogue
  59       * @protected
  60       */
  61      dialogue : null,
  62  
  63      /**
  64       * An array of events attached during the display of the dialogue.
  65       * @property events
  66       * @type Object
  67       * @protected
  68       */
  69      events : [],
  70  
  71      /**
  72       * The node that owns the currently displayed menu.
  73       *
  74       * @property owner
  75       * @type Node
  76       * @default null
  77       */
  78      owner : null,
  79  
  80      /**
  81       * The menu button that toggles this open.
  82       *
  83       * @property menulink
  84       * @type Node
  85       * @protected
  86       */
  87      menulink: null,
  88  
  89      /**
  90       * The set of menu nodes.
  91       *
  92       * @property menuChildren
  93       * @type NodeList
  94       * @protected
  95       */
  96      menuChildren: null,
  97  
  98      /**
  99       * The first menu item.
 100       *
 101       * @property firstMenuChild
 102       * @type Node
 103       * @protected
 104       */
 105      firstMenuChild: null,
 106  
 107      /**
 108       * The last menu item.
 109       *
 110       * @property lastMenuChild
 111       * @type Node
 112       * @protected
 113       */
 114      lastMenuChild: null,
 115  
 116      /**
 117       * Called during the initialisation process of the object.
 118       *
 119       * @method initializer
 120       */
 121      initializer : function() {
 122          Y.log('Initialising the action menu manager', 'debug', ACTIONMENU.NAME);
 123          Y.all(SELECTOR.MENU).each(this.enhance, this);
 124          BODY.delegate('key', this.moveMenuItem, 'down:37,39', SELECTOR.MENUBARITEMS.join(','), this);
 125  
 126          BODY.delegate('click', this.toggleMenu, SELECTOR.MENU + ' ' + SELECTOR.TOGGLE, this);
 127          BODY.delegate('key', this.showIfHidden, 'down:enter,38,40', SELECTOR.MENU + ' ' + SELECTOR.TOGGLE, this);
 128  
 129          // Ensure that we toggle on menuitems when the spacebar is pressed.
 130          BODY.delegate('key', function(e) {
 131              e.currentTarget.simulate('click');
 132              e.preventDefault();
 133          }, 'down:32', SELECTOR.MENUBARITEMS.join(','));
 134      },
 135  
 136      /**
 137       * Enhances a menu adding aria attributes and flagging it as functional.
 138       *
 139       * @method enhance
 140       * @param {Node} menu
 141       * @return boolean
 142       */
 143      enhance : function(menu) {
 144          var menucontent = menu.one(SELECTOR.MENUCONTENT),
 145              align;
 146          if (!menucontent) {
 147              return false;
 148          }
 149          align = menucontent.getData('align') || this.get('align').join('-');
 150          menu.one(SELECTOR.TOGGLE).set('aria-haspopup', true);
 151          menucontent.set('aria-hidden', true);
 152          if (!menucontent.hasClass('align-'+align)) {
 153              menucontent.addClass('align-'+align);
 154          }
 155          if (menucontent.hasChildNodes()) {
 156              menu.setAttribute('data-enhanced', '1');
 157          }
 158      },
 159  
 160      /**
 161       * Handle movement between menu items in a menubar.
 162       *
 163       * @method moveMenuItem
 164       * @param {EventFacade} e The event generating the move request
 165       * @chainable
 166       */
 167      moveMenuItem: function(e) {
 168          var nextFocus,
 169              menuitem = e.target.ancestor(SELECTOR.MENUITEM, true);
 170  
 171          if (e.keyCode === 37) {
 172              nextFocus = this.getMenuItem(menuitem, true);
 173          } else if (e.keyCode === 39) {
 174              nextFocus = this.getMenuItem(menuitem);
 175          }
 176  
 177          if (nextFocus) {
 178              nextFocus.focus();
 179          }
 180          return this;
 181      },
 182  
 183      /**
 184       * Get the next menuitem in a menubar.
 185       *
 186       * @method getMenuItem
 187       * @param {Node} currentItem The currently focused item in the menubar
 188       * @param {Boolean} [previous=false] Move backwards in the menubar instead of forwards
 189       * @return {Node|null} The next item, or null if none was found
 190       */
 191      getMenuItem: function(currentItem, previous) {
 192          var menubar = currentItem.ancestor(SELECTOR.MENUBAR),
 193              menuitems;
 194  
 195          if (!menubar) {
 196              return null;
 197          }
 198  
 199          menuitems = menubar.all(SELECTOR.MENUITEMS.join(','));
 200  
 201          if (!menuitems) {
 202              return null;
 203          }
 204  
 205          var childCount = menuitems.size();
 206  
 207          if (childCount === 1) {
 208              // Only one item, exit now because we should already be on it.
 209              return null;
 210          }
 211  
 212          // Determine the next child.
 213          var index = 0,
 214              direction = 1,
 215              checkCount = 0;
 216  
 217          // Work out the index of the currently selected item.
 218          for (index = 0; index < childCount; index++) {
 219              if (menuitems.item(index) === currentItem) {
 220                  break;
 221              }
 222          }
 223  
 224          // Check that the menu item was found - otherwise return null.
 225          if (menuitems.item(index) !== currentItem) {
 226              return null;
 227          }
 228  
 229          // Reverse the direction if we want the previous item.
 230          if (previous) {
 231              direction = -1;
 232          }
 233  
 234          do {
 235              // Update the index in the direction of travel.
 236              index += direction;
 237  
 238              next = menuitems.item(index);
 239  
 240              // Check that we don't loop multiple times.
 241              checkCount++;
 242          } while (next && next.hasAttribute('hidden'));
 243  
 244          return next;
 245      },
 246  
 247      /**
 248       * Hides the menu if it is visible.
 249       * @method hideMenu
 250       */
 251      hideMenu : function() {
 252          if (this.dialogue) {
 253              Y.log('Hiding an action menu', 'debug', ACTIONMENU.NAME);
 254              this.dialogue.removeClass('show');
 255              this.dialogue.one(SELECTOR.MENUCONTENT).set('aria-hidden', true);
 256              this.dialogue = null;
 257          }
 258          for (var i in this.events) {
 259              if (this.events[i].detach) {
 260                  this.events[i].detach();
 261              }
 262          }
 263          this.events = [];
 264          if (this.owner) {
 265              this.owner.removeClass(CSS.MENUSHOWN);
 266              this.owner = null;
 267          }
 268  
 269          if (this.menulink) {
 270              this.menulink.focus();
 271              this.menulink = null;
 272          }
 273      },
 274  
 275      showIfHidden: function(e) {
 276          var menu = e.target.ancestor(SELECTOR.MENU),
 277              menuvisible = (menu.hasClass('show'));
 278  
 279          if (!menuvisible) {
 280              e.preventDefault();
 281              this.showMenu(e, menu);
 282          }
 283          return this;
 284      },
 285  
 286      /**
 287       * Toggles the display of the menu.
 288       * @method toggleMenu
 289       * @param {EventFacade} e
 290       */
 291      toggleMenu : function(e) {
 292          var menu = e.target.ancestor(SELECTOR.MENU),
 293              menuvisible = (menu.hasClass('show'));
 294  
 295          // Prevent event propagation as it will trigger the hideIfOutside event handler in certain situations.
 296          e.halt(true);
 297          this.hideMenu();
 298          if (menuvisible) {
 299              // The menu was visible and the user has clicked to toggle it again.
 300              return;
 301          }
 302          this.showMenu(e, menu);
 303      },
 304  
 305      /**
 306       * Handle keyboard events when the menu is open. We respond to:
 307       * * escape (exit)
 308       * * tab (move to next menu item)
 309       * * up/down (move to previous/next menu item)
 310       *
 311       * @method handleKeyboardEvent
 312       * @param {EventFacade} e The key event
 313       */
 314      handleKeyboardEvent: function(e) {
 315          var next;
 316  
 317          // Handle when the menu is still selected.
 318          if (e.currentTarget.ancestor(SELECTOR.TOGGLE, true)) {
 319              if ((e.keyCode === 40 || (e.keyCode === 9 && !e.shiftKey)) && this.firstMenuChild) {
 320                  this.firstMenuChild.focus();
 321                  e.preventDefault();
 322              } else if (e.keyCode === 38 && this.lastMenuChild) {
 323                  this.lastMenuChild.focus();
 324                  e.preventDefault();
 325              } else if (e.keyCode === 9 && e.shiftKey) {
 326                  this.hideMenu();
 327                  e.preventDefault();
 328              }
 329              return this;
 330          }
 331  
 332          if (e.keyCode === 27) {
 333              // The escape key was pressed so close the menu.
 334              this.hideMenu();
 335              e.preventDefault();
 336  
 337          } else if (e.keyCode === 32) {
 338              // The space bar was pressed. Trigger a click.
 339              e.preventDefault();
 340              e.currentTarget.simulate('click');
 341          } else if (e.keyCode === 9) {
 342              // The tab key was pressed. Tab moves forwards, Shift + Tab moves backwards through the menu options.
 343              // We only override the Shift + Tab on the first option, and Tab on the last option to change where the focus is moved to.
 344              if (e.target === this.firstMenuChild && e.shiftKey) {
 345                  this.hideMenu();
 346                  e.preventDefault();
 347              } else if (e.target === this.lastMenuChild && !e.shiftKey) {
 348                  if (this.hideMenu()) {
 349                      // Determine the next selector and focus on it.
 350                      next = this.menulink.next(SELECTOR.CAN_RECEIVE_FOCUS_SELECTOR);
 351                      if (next) {
 352                          next.focus();
 353                      }
 354                  }
 355              }
 356  
 357          } else if (e.keyCode === 38 || e.keyCode === 40) {
 358              // The up (38) or down (40) key was pushed.
 359              // On cursor moves we loops through the menu rather than exiting it as in the tab behaviour.
 360              var found = false,
 361                  index = 0,
 362                  direction = 1,
 363                  checkCount = 0;
 364  
 365              // Determine which menu item is currently selected.
 366              while (!found && index < this.menuChildren.size()) {
 367                  if (this.menuChildren.item(index) === e.currentTarget) {
 368                      found = true;
 369                  } else {
 370                      index++;
 371                  }
 372              }
 373  
 374              if (!found) {
 375                  Y.log("Unable to find this menu item in the list of menu children", 'debug', 'moodle-core-actionmenu');
 376                  return;
 377              }
 378  
 379              if (e.keyCode === 38) {
 380                  // Moving up so reverse the direction.
 381                  direction = -1;
 382              }
 383  
 384              // Try to find the next
 385              do {
 386                  index += direction;
 387                  if (index < 0) {
 388                      index = this.menuChildren.size() - 1;
 389                  } else if (index >= this.menuChildren.size()) {
 390                      // Handle wrapping.
 391                      index = 0;
 392                  }
 393                  next = this.menuChildren.item(index);
 394  
 395                  // Add a counter to ensure we don't get stuck in a loop if there's only one visible menu item.
 396                  checkCount++;
 397              } while (checkCount < this.menuChildren.size() && next !== e.currentTarget && next.hasClass('hidden'));
 398  
 399              if (next) {
 400                  next.focus();
 401                  e.preventDefault();
 402              }
 403          }
 404      },
 405  
 406      /**
 407       * Hides the menu if the event happened outside the menu.
 408       *
 409       * @protected
 410       * @method hideIfOutside
 411       * @param {EventFacade} e
 412       */
 413      hideIfOutside : function(e) {
 414          if (!e.target.ancestor(SELECTOR.MENUCHILD, true)) {
 415              this.hideMenu();
 416          }
 417      },
 418  
 419      /**
 420       * Displays the menu with the given content and alignment.
 421       *
 422       * @method showMenu
 423       * @param {EventFacade} e
 424       * @param {Node} menu
 425       * @return M.core.dialogue
 426       */
 427      showMenu : function(e, menu) {
 428          Y.log('Displaying an action menu', 'debug', ACTIONMENU.NAME);
 429          var ownerselector = menu.getData('owner'),
 430              menucontent = menu.one(SELECTOR.MENUCONTENT);
 431          this.owner = (ownerselector) ? menu.ancestor(ownerselector) : null;
 432          this.dialogue = menu;
 433          menu.addClass('show');
 434          if (this.owner) {
 435              this.owner.addClass(CSS.MENUSHOWN);
 436              this.menulink = this.owner.one(SELECTOR.TOGGLE);
 437          } else {
 438              this.menulink = e.target.ancestor(SELECTOR.TOGGLE, true);
 439          }
 440          this.constrain(menucontent.set('aria-hidden', false));
 441  
 442          this.menuChildren = this.dialogue.all(SELECTOR.MENUCHILD);
 443          if (this.menuChildren) {
 444              this.firstMenuChild = this.menuChildren.item(0);
 445              this.lastMenuChild  = this.menuChildren.item(this.menuChildren.size() - 1);
 446  
 447              this.firstMenuChild.focus();
 448          }
 449  
 450          // Close the menu if the user presses escape.
 451          this.events.push(BODY.on('key', this.hideMenu, 'esc', this));
 452  
 453          // Close the menu if the user clicks outside the menu.
 454          this.events.push(BODY.on('click', this.hideIfOutside, this));
 455  
 456          // Close the menu if the user focuses outside the menu.
 457          this.events.push(BODY.delegate('focus', this.hideIfOutside, '*', this));
 458  
 459          // Check keyboard changes.
 460          this.events.push(menu.delegate('key', this.handleKeyboardEvent, 'down:9, 27, 38, 40, 32', SELECTOR.MENUCHILD + ', ' + SELECTOR.TOGGLE, this));
 461  
 462          // Close the menu after a button was pushed.
 463          this.events.push(menu.delegate('click', function(e) {
 464              if (e.currentTarget.test(SELECTOR.KEEPOPEN)) {
 465                  return;
 466              }
 467              this.hideMenu();
 468          }, SELECTOR.MENUCHILD, this));
 469  
 470          return true;
 471      },
 472  
 473      /**
 474       * Constrains the node to its the page width.
 475       *
 476       * @method constrain
 477       * @param {Node} node
 478       */
 479      constrain : function(node) {
 480          var selector = node.getData('constraint'),
 481              nx = node.getX(),
 482              ny = node.getY(),
 483              nwidth = node.get('offsetWidth'),
 484              nheight = node.get('offsetHeight'),
 485              cx = 0,
 486              cy = 0,
 487              cwidth,
 488              cheight,
 489              coverflow = 'auto',
 490              newwidth = null,
 491              newheight = null,
 492              newleft = null,
 493              newtop = null,
 494              boxshadow = null;
 495  
 496          if (selector) {
 497              selector = node.ancestor(selector);
 498          }
 499          if (selector) {
 500              cwidth = selector.get('offsetWidth');
 501              cheight = selector.get('offsetHeight');
 502              cx = selector.getX();
 503              cy = selector.getY();
 504              coverflow = selector.getStyle('overflow') || 'auto';
 505          } else {
 506              cwidth = node.get('docWidth');
 507              cheight = node.get('docHeight');
 508          }
 509  
 510          // Constrain X.
 511          // First up if the width is more than the constrain its easily full width + full height.
 512          if (nwidth > cwidth) {
 513              // The width of the constraint.
 514              newwidth = nwidth = cwidth;
 515              // The constraints xpoint.
 516              newleft = nx = cx;
 517          } else {
 518              if (nx < cx) {
 519                  // If nx is less than cx we need to move it right.
 520                  newleft = nx = cx;
 521              } else if (nx + nwidth >= cx + cwidth) {
 522                  // The top right of the node is outside of the constraint, move it in.
 523                  newleft = cx + cwidth - nwidth;
 524              }
 525          }
 526  
 527          // Constrain Y.
 528          if (nheight > cheight && coverflow.toLowerCase() === 'hidden') {
 529              // The node extends over the constrained area and would be clipped.
 530              // Reduce the height of the node and force its overflow to scroll.
 531              newheight = nheight = cheight;
 532              node.setStyle('overflow', 'auto');
 533          }
 534          // If the node is below the top of the constraint AND
 535          //    the node is longer than the constraint allows.
 536          if (ny >= cy && ny + nheight > cy + cheight) {
 537              // Move it up.
 538              newtop = cy + cheight - nheight;
 539              try {
 540                  boxshadow = node.getStyle('boxShadow').replace(/.*? (\d+)px \d+px$/, '$1');
 541                  if (new RegExp(/^\d+$/).test(boxshadow) && newtop - cy > boxshadow) {
 542                      newtop -= boxshadow;
 543                  }
 544              } catch (ex) {
 545                  Y.log('Failed to determine box-shadow margin.', 'warn', ACTIONMENU.NAME);
 546              }
 547          }
 548  
 549          if (newleft !== null) {
 550              node.setX(newleft);
 551          }
 552          if (newtop !== null) {
 553              node.setY(newtop);
 554          }
 555          if (newwidth !== null) {
 556              node.setStyle('width', newwidth.toString() + 'px');
 557          }
 558          if (newheight !== null) {
 559              node.setStyle('height', newheight.toString() + 'px');
 560          }
 561      }
 562  };
 563  
 564  Y.extend(ACTIONMENU, Y.Base, ACTIONMENU.prototype, {
 565      NAME : 'moodle-core-actionmenu',
 566      ATTRS : {
 567          align : {
 568              value : [
 569                  ALIGN.TR, // The dialogue.
 570                  ALIGN.BR  // The button
 571              ]
 572          }
 573      }
 574  });
 575  
 576  M.core = M.core || {};
 577  M.core.actionmenu = M.core.actionmenu || {};
 578  
 579  /**
 580   *
 581   * @static
 582   * @property M.core.actionmenu.instance
 583   * @type {ACTIONMENU}
 584   */
 585  M.core.actionmenu.instance = null;
 586  
 587  /**
 588   * Init function - will only ever create one instance of the actionmenu class.
 589   *
 590   * @method M.core.actionmenu.init
 591   * @static
 592   * @param {Object} params
 593   */
 594  M.core.actionmenu.init = M.core.actionmenu.init || function(params) {
 595      M.core.actionmenu.instance = M.core.actionmenu.instance || new ACTIONMENU(params);
 596  };
 597  
 598  /**
 599   * Registers a new DOM node with the action menu causing it to be enhanced if required.
 600   *
 601   * @method M.core.actionmenu.newDOMNode
 602   * @param node
 603   * @return {boolean}
 604   */
 605  M.core.actionmenu.newDOMNode = function(node) {
 606      if (M.core.actionmenu.instance === null) {
 607          return true;
 608      }
 609      node.all(SELECTOR.MENU).each(M.core.actionmenu.instance.enhance, M.core.actionmenu.instance);
 610  };
 611  
 612  
 613  }, '@VERSION@', {"requires": ["base", "event", "node-event-simulate"]});