/**
 * @file
 * Attaches the behaviors for the Overlay parent pages.
 */

(function ($, Drupal, displace) {

"use strict";

/**
 * Open the overlay, or load content into it, when an admin link is clicked.
 */
Drupal.behaviors.overlayParent = {
  attach: function (context, settings) {
    if (this.processed) {
      return;
    }
    this.processed = true;

    $(window)
      // When the hash (URL fragment) changes, open the overlay if needed.
      .bind('hashchange.drupal-overlay', $.proxy(Drupal.overlay, 'eventhandlerOperateByURLFragment'))
      // Trigger the hashchange handler once, after the page is loaded, so that
      // permalinks open the overlay.
      .triggerHandler('hashchange.drupal-overlay');

    // Do not use the overlay on devices with low screen width.
    // @todo Replace with conditional loading.
    if(!Drupal.checkWidthBreakpoint()) {
      return;
    }

    $(document)
      // Instead of binding a click event handler to every link we bind one to
      // the document and only handle events that bubble up. This allows other
      // scripts to bind their own handlers to links and also to prevent
      // overlay's handling.
      .bind('click.drupal-overlay mouseup.drupal-overlay', $.proxy(Drupal.overlay, 'eventhandlerOverrideLink'));
  }
};

/**
 * Overlay object for parent windows.
 *
 * Events
 * Overlay triggers a number of events that can be used by other scripts.
 * - drupalOverlayOpen: This event is triggered when the overlay is opened.
 * - drupalOverlayBeforeClose: This event is triggered when the overlay attempts
 *   to close. If an event handler returns false, the close will be prevented.
 * - drupalOverlayClose: This event is triggered when the overlay is closed.
 * - drupalOverlayBeforeLoad: This event is triggered right before a new URL
 *   is loaded into the overlay.
 * - drupalOverlayReady: This event is triggered when the DOM of the overlay
 *   child document is fully loaded.
 * - drupalOverlayLoad: This event is triggered when the overlay is finished
 *   loading.
 * - drupalOverlayResize: This event is triggered when the overlay is being
 *   resized to match the parent window.
 */
Drupal.overlay = Drupal.overlay || {
  isOpen: false,
  isOpening: false,
  isClosing: false,
  isLoading: false
};

Drupal.overlay.prototype = {};

/**
 * Open the overlay.
 *
 * @param url
 *   The URL of the page to open in the overlay.
 *
 * @return
 *   TRUE if the overlay was opened, FALSE otherwise.
 */
Drupal.overlay.open = function (url) {
  // Just one overlay is allowed.
  if (this.isOpen || this.isOpening) {
    return this.load(url);
  }
  this.isOpening = true;
  // Store the original document title.
  this.originalTitle = document.title;

  // Create the dialog and related DOM elements.
  this.create();

  this.isOpening = false;
  this.isOpen = true;
  $(document.documentElement).addClass('overlay-open');

  // Allow other scripts to respond to this event.
  $(document).trigger('drupalOverlayOpen');

  return this.load(url);
};

/**
 * Create the underlying markup and behaviors for the overlay.
 */
Drupal.overlay.create = function () {
  // Update offsets values on the page.
  displace(false);

  // Build the overlay container.
  this.$container = $(Drupal.theme('overlayContainer'))
    .appendTo(document.body);

  // Overlay uses transparent iframes that cover the full parent window.
  // When the overlay is open the scrollbar of the parent window is hidden.
  // Because some browsers show a white iframe background for a short moment
  // while loading a page into an iframe, overlay uses two iframes. By loading
  // the page in a hidden (inactive) iframe the user doesn't see the white
  // background. When the page is loaded the active and inactive iframes
  // are switched.
  this.activeFrame = this.$iframeA = $(Drupal.theme('overlayElement'))
    .appendTo(this.$container);

  this.inactiveFrame = this.$iframeB = $(Drupal.theme('overlayElement'))
    .appendTo(this.$container);

  this.$iframeA.bind('load.drupal-overlay', { self: this.$iframeA[0], sibling: this.$iframeB }, $.proxy(this, 'loadChild'));
  this.$iframeB.bind('load.drupal-overlay', { self: this.$iframeB[0], sibling: this.$iframeA }, $.proxy(this, 'loadChild'));

  // Add a second class "drupal-overlay-open" to indicate these event handlers
  // should only be bound when the overlay is open.
  var eventClass = '.drupal-overlay.drupal-overlay-open';
  $(window)
    .bind('resize' + eventClass, $.proxy(this, 'eventhandlerOuterResize'));
  $(document)
    .bind('drupalViewportOffsetChange' + eventClass, $.proxy(this, 'eventhandlerViewportOffsetChange'))
    .bind('drupalOverlayLoad' + eventClass, $.proxy(this, 'eventhandlerOuterResize'))
    .bind('drupalOverlayReady' + eventClass +
          ' drupalOverlayClose' + eventClass, $.proxy(this, 'eventhandlerSyncURLFragment'))
    .bind('drupalOverlayClose' + eventClass, $.proxy(this, 'eventhandlerRefreshPage'))
    .bind('drupalOverlayBeforeClose' + eventClass +
          ' drupalOverlayBeforeLoad' + eventClass +
          ' drupalOverlayResize' + eventClass, $.proxy(this, 'eventhandlerDispatchEvent'));

  $(document)
    .bind('drupalOverlayResize' + eventClass, $.proxy(this, 'eventhandlerAlterDisplacedElements'))
    .bind('drupalOverlayClose' + eventClass, $.proxy(this, 'eventhandlerRestoreDisplacedElements'));
};

/**
 * Load the given URL into the overlay iframe.
 *
 * Use this method to change the URL being loaded in the overlay if it is
 * already open.
 *
 * @return
 *   TRUE if URL is loaded into the overlay, FALSE otherwise.
 */
Drupal.overlay.load = function (url) {
  if (!this.isOpen) {
    return false;
  }

  // Allow other scripts to respond to this event.
  $(document).trigger('drupalOverlayBeforeLoad');

  $(document.documentElement).addClass('overlay-loading');

  // The contentDocument property is not supported in IE until IE8.
  var iframeDocument = this.inactiveFrame[0].contentDocument || this.inactiveFrame[0].contentWindow.document;

  // location.replace doesn't create a history entry. location.href does.
  // In this case, we want location.replace, as we're creating the history
  // entry using URL fragments.
  iframeDocument.location.replace(url);

  return true;
};

/**
 * Close the overlay and remove markup related to it from the document.
 *
 * @return
 *   TRUE if the overlay was closed, FALSE otherwise.
 */
Drupal.overlay.close = function () {
  // Prevent double execution when close is requested more than once.
  if (!this.isOpen || this.isClosing) {
    return false;
  }

  // Allow other scripts to respond to this event.
  var event = $.Event('drupalOverlayBeforeClose');
  $(document).trigger(event);
  // If a handler returned false, the close will be prevented.
  if (event.isDefaultPrevented()) {
    return false;
  }

  this.isClosing = true;
  this.isOpen = false;
  $(document.documentElement).removeClass('overlay-open');
  // Restore the original document title.
  document.title = this.originalTitle;

  // Allow other scripts to respond to this event.
  $(document).trigger('drupalOverlayClose');

  Drupal.announce(Drupal.t('Tabbing is no longer constrained by the Overlay module.'));

  // When the iframe is still loading don't destroy it immediately but after
  // the content is loaded (see Drupal.overlay.loadChild).
  if (!this.isLoading) {
    this.destroy();
    this.isClosing = false;
  }
  return true;
};

/**
 * Destroy the overlay.
 */
Drupal.overlay.destroy = function () {
  $([document, window]).unbind('.drupal-overlay-open');
  this.$container.remove();

  this.$container = null;
  this.$iframeA = null;
  this.$iframeB = null;

  this.iframeWindow = null;
};

/**
 * Redirect the overlay parent window to the given URL.
 *
 * @param url
 *   Can be an absolute URL or a relative link to the domain root.
 */
Drupal.overlay.redirect = function (url) {
  // Create a native Link object, so we can use its object methods.
  var link = $(url.link(url)).get(0);

  // If the link is already open, force the hashchange event to simulate reload.
  if (window.location.href === link.href) {
    $(window).triggerHandler('hashchange.drupal-overlay');
  }

  window.location.href = link.href;
  return true;
};

/**
 * Bind the child window.
 *
 * Note that this function is fired earlier than Drupal.overlay.loadChild.
 */
Drupal.overlay.bindChild = function (iframeWindow, isClosing) {
  this.iframeWindow = iframeWindow;

  // We are done if the child window is closing.
  if (isClosing || this.isClosing || !this.isOpen) {
    return;
  }

  // Allow other scripts to respond to this event.
  $(document).trigger('drupalOverlayReady');
};

/**
 * Event handler: load event handler for the overlay iframe.
 *
 * @param event
 *   Event being triggered, with the following restrictions:
 *   - event.type: load
 *   - event.currentTarget: iframe
 */
Drupal.overlay.loadChild = function (event) {
  var iframe = event.data.self;
  var iframeDocument = iframe.contentDocument || iframe.contentWindow.document;
  var iframeWindow = iframeDocument.defaultView || iframeDocument.parentWindow;
  if (iframeWindow.location.href === 'about:blank') {
    return;
  }

  this.isLoading = false;
  $(document.documentElement).removeClass('overlay-loading');
  event.data.sibling.removeClass('overlay-active').prop({ 'tabindex': -1 });

  // Only continue when overlay is still open and not closing.
  if (this.isOpen && !this.isClosing) {
    // And child document is an actual overlayChild.
    if (iframeWindow.Drupal && iframeWindow.Drupal.overlayChild) {
      // Replace the document title with title of iframe.
      document.title = iframeWindow.document.title;

      this.activeFrame = $(iframe)
        .addClass('overlay-active')
        // Add a title attribute to the iframe for accessibility.
        .attr('title', Drupal.t('@title dialog', { '@title': iframeWindow.jQuery('#overlay-title').text() })).prop('tabindex', false);
      this.inactiveFrame = event.data.sibling;

      Drupal.announce(Drupal.t('The overlay has been opened to @title', {'@title': iframeWindow.jQuery('#overlay-title').text()}));

      // Load an empty document into the inactive iframe.
      (this.inactiveFrame[0].contentDocument || this.inactiveFrame[0].contentWindow.document).location.replace('about:blank');

      // Create a fake link before the skip link in order to give it focus.
      var skipLink = iframeWindow.jQuery('[href="#main-content"]');
      Drupal.overlay.setFocusBefore(skipLink, iframeWindow.document);

      // Report these tabbables to the TabbingManger in the parent window.
      Drupal.overlay.releaseTabbing();
      Drupal.overlay.constrainTabbing($(iframeWindow.document).add('#toolbar-administration'));

      Drupal.announce(Drupal.t('Tabbing is constrained to items in the administrative toolbar and the overlay.'));

      // Allow other scripts to respond to this event.
      $(document).trigger('drupalOverlayLoad');
    }
    else {
      window.location = iframeWindow.location.href.replace(/([?&]?)render=overlay&?/g, '$1').replace(/\?$/, '');
    }
  }
  else {
    this.destroy();
  }
};

/**
 * Creates a placeholder element to receive document focus.
 *
 * Setting the document focus to a link will make it visible, even if it's a
 * "skip to main content" link that should normally be visible only when the
 * user tabs to it. This function can be used to set the document focus to
 * just before such an invisible link.
 *
 * @param $element
 *   The jQuery element that should receive focus on the next tab press.
 * @param document
 *   The iframe window element to which the placeholder should be added. The
 *   placeholder element has to be created inside the same iframe as the element
 *   it precedes, to keep IE happy. (http://bugs.jquery.com/ticket/4059)
 */
Drupal.overlay.setFocusBefore = function ($element, document) {
  // Create an anchor inside the placeholder document.
  var placeholder = document.createElement('a');
  var $placeholder = $(placeholder).addClass('element-invisible').attr('href', '#');
  // Put the placeholder where it belongs, and set the document focus to it.
  $placeholder.insertBefore($element);
  $placeholder.attr('autofocus', true);
  // Make the placeholder disappear as soon as it loses focus, so that it
  // doesn't appear in the tab order again.
  $placeholder.one('blur', function () {
    $(this).remove();
  });
};

/**
 * Check if the given link is in the administrative section of the site.
 *
 * @param url
 *   The URL to be tested.
 *
 * @return boolean
 *   TRUE if the URL represents an administrative link, FALSE otherwise.
 */
Drupal.overlay.isAdminLink = function (url) {
  if (Drupal.overlay.isExternalLink(url)) {
    return false;
  }

  var path = this.getPath(url);

  // Turn the list of administrative paths into a regular expression.
  if (!this.adminPathRegExp) {
    var prefix = '';
    if (Drupal.settings.overlay.pathPrefixes.length) {
      // Allow path prefixes used for language negatiation followed by slash,
      // and the empty string.
      prefix = '(' + Drupal.settings.overlay.pathPrefixes.join('/|') + '/|)';
    }
    var adminPaths = '^' + prefix + '(' + Drupal.settings.overlay.paths.admin.replace(/\s+/g, '|') + ')$';
    var nonAdminPaths = '^' + prefix + '(' + Drupal.settings.overlay.paths.non_admin.replace(/\s+/g, '|') + ')$';
    adminPaths = adminPaths.replace(/\*/g, '.*');
    nonAdminPaths = nonAdminPaths.replace(/\*/g, '.*');
    this.adminPathRegExp = new RegExp(adminPaths);
    this.nonAdminPathRegExp = new RegExp(nonAdminPaths);
  }

  return this.adminPathRegExp.exec(path) && !this.nonAdminPathRegExp.exec(path);
};

/**
 * Determine whether a link is external to the site.
 *
 * @param url
 *   The URL to be tested.
 *
 * @return boolean
 *   TRUE if the URL is external to the site, FALSE otherwise.
 */
Drupal.overlay.isExternalLink = function (url) {
  var re = new RegExp('^((f|ht)tps?:)?//(?!' + window.location.host + ')');
  return re.test(url);
};

/**
 * Responds to the drupalViewportOffsetChange event.
 *
 * @param object event
 *   A jQuery event object.
 *
 * @param object offsets
 *   An object whose keys are the for sides an element -- top, right, bottom
 *   and left. The value of each key is the viewport displacement distance for
 *   that edge.
 */
Drupal.overlay.eventhandlerViewportOffsetChange = function (event, offsets) {
  // Allow other scripts to respond to this event.
  $(document).trigger('drupalOverlayResize');
};

/**
 * Event handler: resizes overlay according to the size of the parent window.
 *
 * @param event
 *   Event being triggered, with the following restrictions:
 *   - event.type: any
 *   - event.currentTarget: any
 */
Drupal.overlay.eventhandlerOuterResize = function (event) {
  // Proceed only if the overlay still exists.
  if (!(this.isOpen || this.isOpening) || this.isClosing || !this.iframeWindow) {
    return;
  }

  // IE6 uses position:absolute instead of position:fixed.
  if (typeof document.body.style.maxHeight !== 'string') {
    this.activeFrame.height($(window).height());
  }

  // Allow other scripts to respond to this event.
  $(document).trigger('drupalOverlayResize');
};

/**
 * Event handler: resizes displaced elements so they won't overlap the scrollbar
 * of overlay's iframe.
 *
 * @param event
 *   Event being triggered, with the following restrictions:
 *   - event.type: any
 *   - event.currentTarget: any
 */
Drupal.overlay.eventhandlerAlterDisplacedElements = function (event) {
  // Proceed only if the overlay still exists.
  if (!(this.isOpen || this.isOpening) || this.isClosing || !this.iframeWindow) {
    return;
  }

  var offsets = displace.offsets;

  // Move the body of the iframe contentDocument inward a sufficient distance
  // to prevent it from appearing underneath displacing elements like the
  // toolbar.
  var iframeBody = this.iframeWindow.document.body;
  $(iframeBody).css({
    'padding-top': offsets.top,
    'padding-right': offsets.right,
    'padding-bottom': offsets.bottom,
    'padding-left': offsets.left
  });
  // Trigger a repaint.
  iframeBody.style.display = 'none';
  iframeBody.style.display = 'block';

  // Constrain the width of offsetting top and bottom elements, such as the
  // toolbar, so that a scroll in the overlay iframe won't be occluded.
  var iframeBodyWidth = iframeBody.clientWidth;
  if (iframeBodyWidth > 0 && iframeBodyWidth < document.documentElement.clientWidth) {
    $('[data-offset-top], [data-offset-bottom]').css('max-width', iframeBodyWidth);
  }
};

/**
 * Event handler: restores size of displaced elements as they were before
 * overlay was opened.
 *
 * @param event
 *   Event being triggered, with the following restrictions:
 *   - event.type: any
 *   - event.currentTarget: any
 */
Drupal.overlay.eventhandlerRestoreDisplacedElements = function (event) {
  $('[data-offset-top], [data-offset-bottom]').css('max-width', 'none');
};

/**
 * Event handler: overrides href of administrative links to be opened in
 * the overlay.
 *
 * This click event handler should be bound to any document (for example the
 * overlay iframe) of which you want links to open in the overlay.
 *
 * @param event
 *   Event being triggered, with the following restrictions:
 *   - event.type: click, mouseup
 *   - event.currentTarget: document
 *
 * @see Drupal.overlayChild.behaviors.addClickHandler
 */
Drupal.overlay.eventhandlerOverrideLink = function (event) {
  // In some browsers the click event isn't fired for right-clicks. Use the
  // mouseup event for right-clicks and the click event for everything else.
  if ((event.type === 'click' && event.button === 2) || (event.type === 'mouseup' && event.button !== 2)) {
    return;
  }

  var $target = $(event.target);

  // Only continue if clicked target (or one of its parents) is a link.
  if (!$target.is('a')) {
    $target = $target.closest('a');
    if (!$target.length) {
      return;
    }
  }

  // Never open links in the overlay that contain the overlay-exclude class.
  if ($target.hasClass('overlay-exclude')) {
    return;
  }

  // Close the overlay when the link contains the overlay-close class.
  if ($target.hasClass('overlay-close')) {
    // Clearing the overlay URL fragment will close the overlay.
    $.bbq.removeState('overlay');
    return;
  }

  var target = $target[0];
  var href = target.href;
  // Only handle links that have an href attribute and use the HTTP(S) protocol.
  if (typeof href !== 'undefined' && href !== '' && (/^https?\:/).test(target.protocol)) {
    var anchor = href.replace(target.ownerDocument.location.href, '');
    // Skip anchor links.
    if (anchor.length === 0 || anchor.charAt(0) === '#') {
      return;
    }
    // Open admin links in the overlay.
    else if (this.isAdminLink(href)) {
      // If the link contains the overlay-restore class and the overlay-context
      // state is set, also update the parent window's location.
      var parentLocation = ($target.hasClass('overlay-restore') && typeof $.bbq.getState('overlay-context') === 'string') ? Drupal.url($.bbq.getState('overlay-context')) : null;
      href = this.fragmentizeLink($target.get(0), parentLocation);
      // Only override default behavior when left-clicking and user is not
      // pressing the ALT, CTRL, META (Command key on the Macintosh keyboard)
      // or SHIFT key.
      if (event.button === 0 && !event.altKey && !event.ctrlKey && !event.metaKey && !event.shiftKey) {
        // Redirect to a fragmentized href. This will trigger a hashchange event.
        this.redirect(href);
        // Prevent default action and further propagation of the event.
        return false;
      }
      // Otherwise alter clicked link's href. This is being picked up by
      // the default action handler.
      else {
        $target
          // Restore link's href attribute on blur or next click.
          .one('blur mousedown', { target: target, href: target.href }, function (event) { $(event.data.target).attr('href', event.data.href); })
          .attr('href', href);
      }
    }
    // Non-admin links should close the overlay and open in the main window,
    // which is the default action for a link. We only need to handle them
    // if the overlay is open and the clicked link is inside the overlay iframe.
    else if (this.isOpen && target.ownerDocument === this.iframeWindow.document) {
      // Open external links in the immediate parent of the frame, unless the
      // link already has a different target.
      if (target.hostname !== window.location.hostname) {
        if (!$target.attr('target')) {
          $target.attr('target', '_parent');
        }
      }
      else {
        // Add the overlay-context state to the link, so "overlay-restore" links
        // can restore the context.
        // Leave links with an existing fragment alone. Adding an extra
        // parameter to a link like "node/1#section-1" breaks the link.
        if (!$target[0].hash) {
          // For links with no existing fragment, add the overlay context.
          $target.attr('href', $.param.fragment(href, { 'overlay-context': this.getPath(window.location) + window.location.search }));
        }

        // When the link has a destination query parameter and that destination
        // is an admin link we need to fragmentize it. This will make it reopen
        // in the overlay.
        var params = $.deparam.querystring(href);
        if (params.destination && this.isAdminLink(params.destination)) {
          var fragmentizedDestination = $.param.fragment(this.getPath(window.location), { overlay: params.destination });
          $target.attr('href', $.param.querystring(href, { destination: fragmentizedDestination }));
        }

        // Make the link open in the immediate parent of the frame, unless the
        // link already has a different target.
        if (!$target.attr('target')) {
          $target.attr('target', '_parent');
        }
      }
    }
  }
};

/**
 * Event handler: opens or closes the overlay based on the current URL fragment.
 *
 * @param event
 *   Event being triggered, with the following restrictions:
 *   - event.type: hashchange
 *   - event.currentTarget: document
 */
Drupal.overlay.eventhandlerOperateByURLFragment = function (event) {
  // If we changed the hash to reflect an internal redirect in the overlay,
  // its location has already been changed, so don't do anything.
  if ($.data(window.location, window.location.href) === 'redirect') {
    $.data(window.location, window.location.href, null);
    return;
  }

  // Get the overlay URL from the current URL fragment.
  var state = $.bbq.getState('overlay');
  if (state) {
    // Append render variable, so the server side can choose the right
    // rendering and add child frame code to the page if needed.
    var url = $.param.querystring(Drupal.url(state), { render: 'overlay' });

    this.open(url);
    this.resetActiveClass(this.getPath(url));
  }
  // If there is no overlay URL in the fragment and the overlay is (still)
  // open, close the overlay.
  else if (this.isOpen && !this.isClosing) {
    this.close();
    this.resetActiveClass(this.getPath(window.location));
  }
};

/**
 * Event handler: makes sure the internal overlay URL is reflected in the parent
 * URL fragment.
 *
 * Normally the parent URL fragment determines the overlay location. However, if
 * the overlay redirects internally, the parent doesn't get informed, and the
 * parent URL fragment will be out of date. This is a sanity check to make
 * sure we're in the right place.
 *
 * The parent URL fragment is also not updated automatically when overlay's
 * open, close or load functions are used directly (instead of through
 * eventhandlerOperateByURLFragment).
 *
 * @param event
 *   Event being triggered, with the following restrictions:
 *   - event.type: drupalOverlayReady, drupalOverlayClose
 *   - event.currentTarget: document
 */
Drupal.overlay.eventhandlerSyncURLFragment = function (event) {
  if (this.isOpen) {
    var expected = $.bbq.getState('overlay');
    // This is just a sanity check, so we're comparing paths, not query strings.
    if (this.getPath(Drupal.url(expected)) !== this.getPath(this.iframeWindow.document.location)) {
      // There may have been a redirect inside the child overlay window that the
      // parent wasn't aware of. Update the parent URL fragment appropriately.
      var newLocation = Drupal.overlay.fragmentizeLink(this.iframeWindow.document.location);
      // Set a 'redirect' flag on the new location so the hashchange event handler
      // knows not to change the overlay's content.
      $.data(window.location, newLocation, 'redirect');
      // Use location.replace() so we don't create an extra history entry.
      window.location.replace(newLocation);
    }
  }
  else {
    $.bbq.removeState('overlay');
  }
};

/**
 * Event handler: if the child window suggested that the parent refresh on
 * close, force a page refresh.
 *
 * @param event
 *   Event being triggered, with the following restrictions:
 *   - event.type: drupalOverlayClose
 *   - event.currentTarget: document
 */
Drupal.overlay.eventhandlerRefreshPage = function (event) {
  if (Drupal.overlay.refreshPage) {
    window.location.reload(true);
  }
};

/**
 * Event handler: dispatches events to the overlay document.
 *
 * @param event
 *   Event being triggered, with the following restrictions:
 *   - event.type: any
 *   - event.currentTarget: any
 */
Drupal.overlay.eventhandlerDispatchEvent = function (event) {
  if (this.iframeWindow && this.iframeWindow.document) {
    this.iframeWindow.jQuery(this.iframeWindow.document).trigger(event);
  }
};

/**
 * Make a regular admin link into a URL that will trigger the overlay to open.
 *
 * @param link
 *   A JavaScript Link object (i.e. an <a> element).
 * @param parentLocation
 *   (optional) URL to override the parent window's location with.
 *
 * @return
 *   A URL that will trigger the overlay (in the form
 *   /node/1#overlay=admin/config).
 */
Drupal.overlay.fragmentizeLink = function (link, parentLocation) {
  // Don't operate on links that are already overlay-ready.
  var params = $.deparam.fragment(link.href);
  if (params.overlay) {
    return link.href;
  }

  // Determine the link's original destination.
  var path = this.getPath(link);
  // Preserve existing query and fragment parameters in the URL, except for
  // "render=overlay" which is re-added in Drupal.overlay.eventhandlerOperateByURLFragment.
  var destination = path + link.search.replace(/&?render=overlay/, '').replace(/\?$/, '') + link.hash;

  // Assemble and return the overlay-ready link.
  return $.param.fragment(parentLocation || window.location.href, { overlay: destination });
};

/**
 * Refresh a specific region.
 *
 * @param regionName
 *   Name of the region.
 * @param regionSelector
 *   CSS selector for the region.
 */
function refreshRegion(regionName, regionSelector) {
  var $region = $(regionSelector);
  Drupal.detachBehaviors($region);
  $.get(Drupal.url(Drupal.settings.overlay.ajaxCallback + '/' + regionName), function (newElement) {
    $region.replaceWith($(newElement));
    Drupal.attachBehaviors($region, Drupal.settings);
  });
}

/**
 * Refresh any regions of the page that are displayed outside the overlay.
 *
 * @param data
 *   An array of objects with information on the page regions to be refreshed.
 *   For each object, the key is a CSS class identifying the region to be
 *   refreshed, and the value represents the section of the Drupal $page array
 *   corresponding to this region.
 */
Drupal.overlay.refreshRegions = function (data) {
  var region, region_info, regionClass;
  for (region in data) {
    if (data.hasOwnProperty(region)) {
      region_info = data[region];
      for (regionClass in region_info) {
        if (region_info.hasOwnProperty(regionClass)) {
          refreshRegion(region_info[regionClass], '.' + regionClass);
        }
      }
    }
  }
};

/**
 * Reset the active class on links in displaced elements according to
 * given path.
 *
 * @param activePath
 *   Path to match links against.
 */
Drupal.overlay.resetActiveClass = function(activePath) {
  var self = this;
  var windowDomain = window.location.protocol + window.location.hostname;

  $('#toolbar-administration')
  .find('a[href]')
  // Remove active class from all links in displaced elements.
  .removeClass('active')
  // Add active class to links that match activePath.
  .each(function () {
    var linkDomain = this.protocol + this.hostname;
    var linkPath = self.getPath(this);

    // A link matches if it is part of the active trail of activePath, except
    // for frontpage links.
    if (linkDomain === windowDomain && (activePath + '/').indexOf(linkPath + '/') === 0 && (linkPath !== '' || activePath === '')) {
      $(this).addClass('active');
    }
  });
};

/**
 * Helper function to get the (corrected) Drupal path of a link.
 *
 * @param link
 *   Link object or string to get the Drupal path from.
 *
 * @return
 *   The Drupal path.
 */
Drupal.overlay.getPath = function (link) {
  if (typeof link === 'string') {
    // Create a native Link object, so we can use its object methods.
    link = $(link.link(link)).get(0);
  }

  var path = link.pathname;
  // Ensure a leading slash on the path, omitted in some browsers.
  if (path.charAt(0) !== '/') {
    path = '/' + path;
  }
  path = path.replace(new RegExp(Drupal.settings.basePath + Drupal.settings.scriptPath), '');

  return path;
};

/**
 * Makes elements outside the overlay unreachable via the tab key.
 */
Drupal.overlay.constrainTabbing = function ($tabbables) {
  // If a tabset is already active, return without creating a new one.
  if (this.tabset && !this.tabset.released) {
    return;
  }
  // Leave links inside the overlay and toolbars alone.
  this.tabset = Drupal.tabbingManager.constrain($tabbables);
  var self = this;
  $(document).on('drupalOverlayClose.tabbing', function () {
    self.tabset.release();
    $(document).off('drupalOverlayClose.tabbing');
  });
};

/**
 *
 */
Drupal.overlay.releaseTabbing = function () {
  if (this.tabset) {
    this.tabset.release();
    delete this.tabset;
  }
};

$.extend(Drupal.theme, {
  /**
   * Theme function to create the overlay iframe element.
   */
  overlayContainer: function () {
    return '<div id="overlay-container"><div class="overlay-modal-background"></div></div>';
  },

  /**
   * Theme function to create an overlay iframe element.
   */
  overlayElement: function (url) {
    return '<iframe class="overlay-element" frameborder="0" scrolling="auto" allowtransparency="true"></iframe>';
  }
});

})(jQuery, Drupal, Drupal.displace);