/* ==========================================================

  * bootstrap-affix.js v2.3.1

  * http://twitter.github.com/bootstrap/javascript.html#affix

  * ==========================================================

  * Copyright 2012 Twitter, Inc.

  *

  * Licensed under the Apache License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  * http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  * ========================================================== */

 !function ($) {

   "use strict"; // jshint ;_;

  /* AFFIX CLASS DEFINITION

   * ====================== */

   var Affix = function (element, options) {

     this.options = $.extend({}, $.fn.affix.defaults, options)

     this.$window = $(window)

       .on('scroll.affix.data-api', $.proxy(this.checkPosition, this))

       .on('click.affix.data-api',  $.proxy(function () { setTimeout($.proxy(this.checkPosition, this), 1) }, this))

     this.$element = $(element)

     this.checkPosition()

   }

   Affix.prototype.checkPosition = function () {

     if (!this.$element.is(':visible')) return

     var scrollHeight = $(document).height()

       , scrollTop = this.$window.scrollTop()

       , position = this.$element.offset()

       , offset = this.options.offset

       , offsetBottom = offset.bottom

       , offsetTop = offset.top

       , reset = 'affix affix-top affix-bottom'

       , affix

     if (typeof offset != 'object') offsetBottom = offsetTop = offset

     if (typeof offsetTop == 'function') offsetTop = offset.top()

     if (typeof offsetBottom == 'function') offsetBottom = offset.bottom()

     affix = this.unpin != null && (scrollTop + this.unpin <= position.top) ?

       false    : offsetBottom != null && (position.top + this.$element.height() >= scrollHeight - offsetBottom) ?

       'bottom' : offsetTop != null && scrollTop <= offsetTop ?

       'top'    : false

     if (this.affixed === affix) return

     this.affixed = affix

     this.unpin = affix == 'bottom' ? position.top - scrollTop : null

     this.$element.removeClass(reset).addClass('affix' + (affix ? '-' + affix : ''))

   }

  /* AFFIX PLUGIN DEFINITION

   * ======================= */

   var old = $.fn.affix

   $.fn.affix = function (option) {

     return this.each(function () {

       var $this = $(this)

         , data = $this.data('affix')

         , options = typeof option == 'object' && option

       if (!data) $this.data('affix', (data = new Affix(this, options)))

       if (typeof option == 'string') data[option]()

     })

   }

   $.fn.affix.Constructor = Affix

   $.fn.affix.defaults = {

     offset: 0

   }

  /* AFFIX NO CONFLICT

   * ================= */

   $.fn.affix.noConflict = function () {

     $.fn.affix = old

     return this

   }

  /* AFFIX DATA-API

   * ============== */

   $(window).on('load', function () {

     $('[data-spy="affix"]').each(function () {

       var $spy = $(this)

         , data = $spy.data()

       data.offset = data.offset || {}

       data.offsetBottom && (data.offset.bottom = data.offsetBottom)

       data.offsetTop && (data.offset.top = data.offsetTop)

       $spy.affix(data)

     })

   })

 }(window.jQuery);