(function ($) {

/**

 * This script transforms a set of fieldsets into a stack of vertical

 * tabs. Another tab pane can be selected by clicking on the respective

 * tab.

 *

 * Each tab may have a summary which can be updated by another

 * script. For that to work, each fieldset has an associated

 * 'verticalTabCallback' (with jQuery.data() attached to the fieldset),

 * which is called every time the user performs an update to a form

 * element inside the tab pane.

 */

Drupal.behaviors.verticalTabs = {

  attach: function (context) {

    $('.vertical-tabs-panes', context).once('vertical-tabs', function () {

      var focusID = $(':hidden.vertical-tabs-active-tab', this).val();

      var tab_focus;

      // Check if there are some fieldsets that can be converted to vertical-tabs

      var $fieldsets = $('> fieldset', this);

      if ($fieldsets.length == 0) {

        return;

      }

      // Create the tab column.

      var tab_list = $('<ul class="vertical-tabs-list"></ul>');

      $(this).wrap('<div class="vertical-tabs clearfix"></div>').before(tab_list);

      // Transform each fieldset into a tab.

      $fieldsets.each(function () {

        var vertical_tab = new Drupal.verticalTab({

          title: $('> legend', this).text(),

          fieldset: $(this)

        });

        tab_list.append(vertical_tab.item);

        $(this)

          .removeClass('collapsible collapsed')

          .addClass('vertical-tabs-pane')

          .data('verticalTab', vertical_tab);

        if (this.id == focusID) {

          tab_focus = $(this);

        }

      });

      $('> li:first', tab_list).addClass('first');

      $('> li:last', tab_list).addClass('last');

      if (!tab_focus) {

        // If the current URL has a fragment and one of the tabs contains an

        // element that matches the URL fragment, activate that tab.

        if (window.location.hash && $(this).find(window.location.hash).length) {

          tab_focus = $(this).find(window.location.hash).closest('.vertical-tabs-pane');

        }

        else {

          tab_focus = $('> .vertical-tabs-pane:first', this);

        }

      }

      if (tab_focus.length) {

        tab_focus.data('verticalTab').focus();

      }

    });

  }

};

/**

 * The vertical tab object represents a single tab within a tab group.

 *

 * @param settings

 *   An object with the following keys:

 *   - title: The name of the tab.

 *   - fieldset: The jQuery object of the fieldset that is the tab pane.

 */

Drupal.verticalTab = function (settings) {

  var self = this;

  $.extend(this, settings, Drupal.theme('verticalTab', settings));

  this.link.click(function () {

    self.focus();

    return false;

  });

  // Keyboard events added:

  // Pressing the Enter key will open the tab pane.

  this.link.keydown(function(event) {

    if (event.keyCode == 13) {

      self.focus();

      // Set focus on the first input field of the visible fieldset/tab pane.

      $("fieldset.vertical-tabs-pane :input:visible:enabled:first").focus();

      return false;

    }

  });

  this.fieldset

    .bind('summaryUpdated', function () {

      self.updateSummary();

    })

    .trigger('summaryUpdated');

};

Drupal.verticalTab.prototype = {

  /**

   * Displays the tab's content pane.

   */

  focus: function () {

    this.fieldset

      .siblings('fieldset.vertical-tabs-pane')

        .each(function () {

          var tab = $(this).data('verticalTab');

          tab.fieldset.hide();

          tab.item.removeClass('selected');

        })

        .end()

      .show()

      .siblings(':hidden.vertical-tabs-active-tab')

        .val(this.fieldset.attr('id'));

    this.item.addClass('selected');

    // Mark the active tab for screen readers.

    $('#active-vertical-tab').remove();

    this.link.append('<span id="active-vertical-tab" class="element-invisible">' + Drupal.t('(active tab)') + '</span>');

  },

  /**

   * Updates the tab's summary.

   */

  updateSummary: function () {

    this.summary.html(this.fieldset.drupalGetSummary());

  },

  /**

   * Shows a vertical tab pane.

   */

  tabShow: function () {

    // Display the tab.

    this.item.show();

    // Show the vertical tabs.

    this.item.closest('.vertical-tabs').show();

    // Update .first marker for items. We need recurse from parent to retain the

    // actual DOM element order as jQuery implements sortOrder, but not as public

    // method.

    this.item.parent().children('.vertical-tab-button').removeClass('first')

      .filter(':visible:first').addClass('first');

    // Display the fieldset.

    this.fieldset.removeClass('vertical-tab-hidden').show();

    // Focus this tab.

    this.focus();

    return this;

  },

  /**

   * Hides a vertical tab pane.

   */

  tabHide: function () {

    // Hide this tab.

    this.item.hide();

    // Update .first marker for items. We need recurse from parent to retain the

    // actual DOM element order as jQuery implements sortOrder, but not as public

    // method.

    this.item.parent().children('.vertical-tab-button').removeClass('first')

      .filter(':visible:first').addClass('first');

    // Hide the fieldset.

    this.fieldset.addClass('vertical-tab-hidden').hide();

    // Focus the first visible tab (if there is one).

    var $firstTab = this.fieldset.siblings('.vertical-tabs-pane:not(.vertical-tab-hidden):first');

    if ($firstTab.length) {

      $firstTab.data('verticalTab').focus();

    }

    // Hide the vertical tabs (if no tabs remain).

    else {

      this.item.closest('.vertical-tabs').hide();

    }

    return this;

  }

};

/**

 * Theme function for a vertical tab.

 *

 * @param settings

 *   An object with the following keys:

 *   - title: The name of the tab.

 * @return

 *   This function has to return an object with at least these keys:

 *   - item: The root tab jQuery element

 *   - link: The anchor tag that acts as the clickable area of the tab

 *       (jQuery version)

 *   - summary: The jQuery element that contains the tab summary

 */

Drupal.theme.prototype.verticalTab = function (settings) {

  var tab = {};

  tab.item = $('<li class="vertical-tab-button" tabindex="-1"></li>')

    .append(tab.link = $('<a href="#"></a>')

      .append(tab.title = $('<strong></strong>').text(settings.title))

      .append(tab.summary = $('<span class="summary"></span>')

    )

  );

  return tab;

};

})(jQuery);