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

 * Bootstrap: affix.js v3.3.5

 * http://getbootstrap.com/javascript/#affix

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

 * Copyright 2011-2015 Twitter, Inc.

 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)

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

+function ($) {

  'use strict';

  // AFFIX CLASS DEFINITION

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

  var Affix = function (element, options) {

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

    this.$target = $(this.options.target)

      .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      = null

    this.unpin        = null

    this.pinnedOffset = null

    this.checkPosition()

  }

  Affix.VERSION  = '3.3.5'

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

  Affix.DEFAULTS = {

    offset: 0,

    target: window

  }

  Affix.prototype.getState = function (scrollHeight, height, offsetTop, offsetBottom) {

    var scrollTop    = this.$target.scrollTop()

    var position     = this.$element.offset()

    var targetHeight = this.$target.height()

    if (offsetTop != null && this.affixed == 'top') return scrollTop < offsetTop ? 'top' : false

    if (this.affixed == 'bottom') {

      if (offsetTop != null) return (scrollTop + this.unpin <= position.top) ? false : 'bottom'

      return (scrollTop + targetHeight <= scrollHeight - offsetBottom) ? false : 'bottom'

    }

    var initializing   = this.affixed == null

    var colliderTop    = initializing ? scrollTop : position.top

    var colliderHeight = initializing ? targetHeight : height

    if (offsetTop != null && scrollTop <= offsetTop) return 'top'

    if (offsetBottom != null && (colliderTop + colliderHeight >= scrollHeight - offsetBottom)) return 'bottom'

    return false

  }

  Affix.prototype.getPinnedOffset = function () {

    if (this.pinnedOffset) return this.pinnedOffset

    this.$element.removeClass(Affix.RESET).addClass('affix')

    var scrollTop = this.$target.scrollTop()

    var position  = this.$element.offset()

    return (this.pinnedOffset = position.top - scrollTop)

  }

  Affix.prototype.checkPositionWithEventLoop = function () {

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

  }

  Affix.prototype.checkPosition = function () {

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

    var height       = this.$element.height()

    var offset       = this.options.offset

    var offsetTop    = offset.top

    var offsetBottom = offset.bottom

    var scrollHeight = Math.max($(document).height(), $(document.body).height())

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

    if (typeof offsetTop == 'function')    offsetTop    = offset.top(this.$element)

    if (typeof offsetBottom == 'function') offsetBottom = offset.bottom(this.$element)

    var affix = this.getState(scrollHeight, height, offsetTop, offsetBottom)

    if (this.affixed != affix) {

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

      var affixType = 'affix' + (affix ? '-' + affix : '')

      var e         = $.Event(affixType + '.bs.affix')

      this.$element.trigger(e)

      if (e.isDefaultPrevented()) return

      this.affixed = affix

      this.unpin = affix == 'bottom' ? this.getPinnedOffset() : null

      this.$element

        .removeClass(Affix.RESET)

        .addClass(affixType)

        .trigger(affixType.replace('affix', 'affixed') + '.bs.affix')

    }

    if (affix == 'bottom') {

      this.$element.offset({

        top: scrollHeight - height - offsetBottom

      })

    }

  }

  // AFFIX PLUGIN DEFINITION

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

  function Plugin(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]()

    })

  }

  var old = $.fn.affix

  $.fn.affix             = Plugin

  $.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 != null) data.offset.bottom = data.offsetBottom

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

      Plugin.call($spy, data)

    })

  })

}(jQuery);