+function ($) {
  'use strict';

  // COLLAPSE PUBLIC CLASS DEFINITION
  // ================================

  var Collapse = function (element, options) {
    this.$element = $(element);
    this.options = $.extend({}, Collapse.DEFAULTS, options);

    this.transitioning = null;
    this.$trigger = $('[data-toggle="collapse"][href="#' + element.id + '"],' +
                      '[data-toggle="collapse"][data-target="#' + element.id + '"]');

    if (this.options.parent) {
      this.$parent = this.getParent();
    } else {
      this.addAriaAndCollapsedClass(this.$element, this.$trigger);
    }

    if (this.options.toggle) this.toggle();
  };

  Collapse.VERSION = '1.0.0';
  Collapse.TRANSITION_DURATION = 350;
  Collapse.DEFAULTS = {
    toggle: true
  };

  Collapse.prototype.constructor = Collapse;

  Collapse.prototype.dimension = function () {
    var hasWidth = this.$element.hasClass('width');
    return hasWidth ? 'width' : 'height';
  };

  Collapse.prototype.show = function () {
    if (this.transitioning || this.$element.hasClass('in')) return;

    var activesData;
    var actives = this.$parent && this.$parent.children('.panel').children('.in, .collapsing');

    if (actives && actives.length) {
      activesData = actives.data('bs.collapse');
      if (activesData && activesData.transitioning) return;
    }

    var startEvent = $.Event('show.bs.collapse');
    this.$element.trigger(startEvent);

    if (startEvent.isDefaultPrevented()) return;
    if (actives && actives.length) {
      Plugin.call(actives, 'hide');
      activesData || actives.data('bs.collapse', null);
    }

    var dimension = this.dimension();

    this.$element
      .removeClass('collapse')
      .addClass('collapsing')[dimension](0)
      .attr('aria-expanded', true);

    this.$trigger
      .removeClass('collapsed')
      .attr('aria-expanded', true);

    this.transitioning = 1;

    var complete = function () {
      this.$element
        .removeClass('collapsing')
        .addClass('collapse in')[dimension]('');
      this.transitioning = 0;
      this.$element
        .trigger('shown.bs.collapse');
    };

    if (!$.support.transition) return complete.call(this);

    var scrollSize = $.camelCase(['scroll', dimension].join('-'));

    this.$element
      .one('bsTransitionEnd', $.proxy(complete, this))
      .emulateTransitionEnd(Collapse.TRANSITION_DURATION)[dimension](this.$element[0][scrollSize]);
  };

  Collapse.prototype.hide = function () {
    if (this.transitioning || !this.$element.hasClass('in')) return;

    var startEvent = $.Event('hide.bs.collapse');
    this.$element.trigger(startEvent);
    if (startEvent.isDefaultPrevented()) return;

    var dimension = this.dimension();

    this.$element[dimension](this.$element[dimension]())[0].offsetHeight;

    this.$element
      .addClass('collapsing')
      .removeClass('collapse in')
      .attr('aria-expanded', false);

    this.$trigger
      .addClass('collapsed')
      .attr('aria-expanded', false);

    this.transitioning = 1;

    var complete = function () {
      this.transitioning = 0;
      this.$element
        .removeClass('collapsing')
        .addClass('collapse')
        .trigger('hidden.bs.collapse');
    };

    if (!$.support.transition) return complete.call(this);

    this.$element
      [dimension](0)
      .one('bsTransitionEnd', $.proxy(complete, this))
      .emulateTransitionEnd(Collapse.TRANSITION_DURATION);
  };

  Collapse.prototype.toggle = function () {
    this[this.$element.hasClass('in') ? 'hide' : 'show']();
  };

  Collapse.prototype.getParent = function () {
    return $(this.options.parent)
      .find('[data-toggle="collapse"][data-parent="' + this.options.parent + '"]')
      .each($.proxy(function (i, element) {
        var $element = $(element);
        this.addAriaAndCollapsedClass(getTargetFromTrigger($element), $element);
      }, this))
      .end();
  };

  Collapse.prototype.addAriaAndCollapsedClass = function ($element, $trigger) {
    var isOpen = $element.hasClass('in');

    $element.attr('aria-expanded', isOpen);
    $trigger
      .toggleClass('collapsed', !isOpen)
      .attr('aria-expanded', isOpen);
  };

  function getTargetFromTrigger($trigger) {
    var href;
    var target = $trigger.attr('data-target') ||
                 (href = $trigger.attr('href')) && href.replace(/.*(?=#[^\s]+$)/, '');

    return $(target);
  }

  // COLLAPSE PLUGIN DEFINITION
  // ==========================

  function Plugin(option) {
    return this.each(function () {
      var $this = $(this);
      var data = $this.data('bs.collapse');
      var options = $.extend({}, Collapse.DEFAULTS, $this.data(), typeof option === 'object' && option);

      if (!data && options.toggle && /show|hide/.test(option)) options.toggle = false;
      if (!data) $this.data('bs.collapse', (data = new Collapse(this, options)));
      if (typeof option === 'string') data[option]();
    });
  }

  var old = $.fn.collapse;

  $.fn.collapse = Plugin;
  $.fn.collapse.Constructor = Collapse;

  // COLLAPSE NO CONFLICT
  // ====================

  $.fn.collapse.noConflict = function () {
    $.fn.collapse = old;
    return this;
  };

  // COLLAPSE DATA-API
  // =================

  $(document).on('click.bs.collapse.data-api', '[data-toggle="collapse"]', function (e) {
    var $this = $(this);

    if (!$this.attr('data-target')) e.preventDefault();

    var $target = getTargetFromTrigger($this);
    var data = $target.data('bs.collapse');
    var option = data ? 'toggle' : $this.data();

    Plugin.call($target, option);
  });

}(jQuery);