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

 * Bootstrap: affix.js v3.0.0

 * http://twbs.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";

  // AFFIX CLASS DEFINITION

  // ======================

  var Affix = function (element, options) {

    this.options = $.extend({}, Affix.DEFAULTS, options)

    this.$window = $(window)

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

      .on('click.bs.affix.data-api',  $.proxy(this.checkPositionWithEventLoop, this))

    this.$element = $(element)

    this.affixed  =

    this.unpin    = null

    this.checkPosition()

  }

  Affix.RESET = 'affix affix-top affix-bottom'

  Affix.DEFAULTS = {

    offset: 0

  }

  Affix.prototype.checkPositionWithEventLoop = function () {

    setTimeout($.proxy(this.checkPosition, this), 1)

  }

  Affix.prototype.checkPosition = function () {

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

    var scrollHeight = $(document).height()

    var scrollTop    = this.$window.scrollTop()

    var position     = this.$element.offset()

    var offset       = this.options.offset

    var offsetTop    = offset.top

    var offsetBottom = offset.bottom

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

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

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

    var 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

    if (this.unpin) this.$element.css('top', '')

    this.affixed = affix

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

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

    if (affix == 'bottom') {

      this.$element.offset({ top: document.body.offsetHeight - offsetBottom - this.$element.height() })

    }

  }

  // AFFIX PLUGIN DEFINITION

  // =======================

  var old = $.fn.affix

  $.fn.affix = function (option) {

    return this.each(function () {

      var $this   = $(this)

      var data    = $this.data('bs.affix')

      var options = typeof option == 'object' && option

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

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

    })

  }

  $.fn.affix.Constructor = Affix

  // 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)

      var data = $spy.data()

      data.offset = data.offset || {}

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

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

      $spy.affix(data)

    })

  })

}(window.jQuery);