(function ($) {

  if (!$) {
    return
  }

  /**
   * Toggle the visibility of a fieldset using smooth animations.
   */
  Drupal.toggleFieldset = function (fieldset) {
    var $fieldset = $(fieldset)
    if ($fieldset.is('.collapsed')) {
      var $content = $('> .fieldset-wrapper', fieldset).hide()
      $content.addClass('collapse')
      $fieldset
        .removeClass('collapsed')
        .trigger({type: 'collapsed', value: false})
        .find('> legend span.fieldset-legend-prefix').html(Drupal.t('Hide'))
      $content.slideDown({
        duration: 'fast',
        easing  : 'linear',
        complete: function () {
          Drupal.collapseScrollIntoView(fieldset)
          fieldset.animating = false
        },
        step    : function () {
          // Scroll the fieldset into view.
          Drupal.collapseScrollIntoView(fieldset)
        },
      })
    }
    else {
      $fieldset.trigger({type: 'collapsed', value: true})
      $('> .fieldset-wrapper', fieldset).slideUp('fast', function () {
        $fieldset
          .addClass('collapsed')
          .find('> legend span.fieldset-legend-prefix').html(Drupal.t('Show'))
        fieldset.animating = false
      })
    }
  }

  /**
   * Scroll a given fieldset into view as much as possible.
   */
  Drupal.collapseScrollIntoView = function (node) {
    /*var h = document.documentElement.clientHeight || document.body.clientHeight || 0;
    var offset = document.documentElement.scrollTop || document.body.scrollTop || 0;
    var posY = $(node).offset().top;
    var fudge = 55;
    if (posY + node.offsetHeight + fudge > h + offset) {
        if (node.offsetHeight > h) {
            window.scrollTo(0, posY);
        }
        else {
            window.scrollTo(0, posY + node.offsetHeight - h + fudge);
        }
    }*/
  }

  Drupal.behaviors.collapse = {
    attach: function (context, settings) {
      $('fieldset.collapsible', context).once('collapse', function () {
        var $fieldset = $(this)
        // Expand fieldset if there are errors inside, or if it contains an
        // element that is targeted by the URI fragment identifier.
        var anchor = location.hash && location.hash != '#' ? ', ' + location.hash : ''
        if ($fieldset.find('.error' + anchor).length) {
          $fieldset.removeClass('collapsed')
        }

        var summary = $('<span class="summary"></span>')
        $fieldset.bind('summaryUpdated', function () {
          var text = $.trim($fieldset.drupalGetSummary())
          summary.html(text ? ' (' + text + ')' : '')
        })
          .trigger('summaryUpdated')

        // Turn the legend into a clickable link, but retain
        // span.fieldset-legend for CSS positioning.
        var $legend = $('> legend .fieldset-legend', this)

        $('<span class="fieldset-legend-prefix element-invisible"></span>')
          .append($fieldset.hasClass('collapsed') ? Drupal.t('Show') : Drupal.t('Hide'))
          .prependTo($legend)
          .after(' ')

        // .wrapInner() does not retain bound events.
        var $link = $('<a class="fieldset-title" href="#"></a>')
          .prepend($legend.contents())
          .appendTo($legend)
          .click(function () {
            var fieldset = $fieldset.get(0)
            // Don't animate multiple times.
            if (!fieldset.animating) {
              fieldset.animating = true
              Drupal.toggleFieldset(fieldset)
            }
            return false
          })

        $legend.append(summary)
      })
    },
  }

})(window.jQuery || null)