(function() {

  'use strict'



  function noop() {}



  var Waypoint = window.Waypoint



  /* http://imakewebthings.com/waypoints/shortcuts/inview */

  function Inview(options) {

    this.options = Waypoint.Adapter.extend({}, Inview.defaults, options)

    this.axis = this.options.horizontal ? 'horizontal' : 'vertical'

    this.waypoints = []

    this.element = this.options.element

    this.createWaypoints()

  }



  /* Private */

  Inview.prototype.createWaypoints = function() {

    var configs = {

      vertical: [{

        down: 'enter',

        up: 'exited',

        offset: '100%'

      }, {

        down: 'entered',

        up: 'exit',

        offset: 'bottom-in-view'

      }, {

        down: 'exit',

        up: 'entered',

        offset: 0

      }, {

        down: 'exited',

        up: 'enter',

        offset: function() {

          return -this.adapter.outerHeight()

        }

      }],

      horizontal: [{

        right: 'enter',

        left: 'exited',

        offset: '100%'

      }, {

        right: 'entered',

        left: 'exit',

        offset: 'right-in-view'

      }, {

        right: 'exit',

        left: 'entered',

        offset: 0

      }, {

        right: 'exited',

        left: 'enter',

        offset: function() {

          return -this.adapter.outerWidth()

        }

      }]

    }



    for (var i = 0, end = configs[this.axis].length; i < end; i++) {

      var config = configs[this.axis][i]

      this.createWaypoint(config)

    }

  }



  /* Private */

  Inview.prototype.createWaypoint = function(config) {

    var self = this

    this.waypoints.push(new Waypoint({

      context: this.options.context,

      element: this.options.element,

      enabled: this.options.enabled,

      handler: (function(config) {

        return function(direction) {

          self.options[config[direction]].call(self, direction)

        }

      }(config)),

      offset: config.offset,

      horizontal: this.options.horizontal

    }))

  }



  /* Public */

  Inview.prototype.destroy = function() {

    for (var i = 0, end = this.waypoints.length; i < end; i++) {

      this.waypoints[i].destroy()

    }

    this.waypoints = []

  }



  Inview.prototype.disable = function() {

    for (var i = 0, end = this.waypoints.length; i < end; i++) {

      this.waypoints[i].disable()

    }

  }



  Inview.prototype.enable = function() {

    for (var i = 0, end = this.waypoints.length; i < end; i++) {

      this.waypoints[i].enable()

    }

  }



  Inview.defaults = {

    context: window,

    enabled: true,

    enter: noop,

    entered: noop,

    exit: noop,

    exited: noop

  }



  Waypoint.Inview = Inview

}())

