// jQuery Scrollstop Plugin v1.2.0
// https://github.com/ssorallen/jquery-scrollstop

(function (factory) {
  // UMD[2] wrapper for jQuery plugins to work in AMD or in CommonJS.
  //
  // [2] https://github.com/umdjs/umd

  if (typeof define === 'function' && define.amd) {
    // AMD. Register as an anonymous module.
    define(['jquery'], factory);
  } else if (typeof exports === 'object') {
    // Node/CommonJS
    module.exports = factory(require('jquery'));
  } else {
    // Browser globals
    factory(jQuery);
  }
}(function ($) {
  // $.event.dispatch was undocumented and was deprecated in jQuery 1.7[1]. It
  // was replaced by $.event.handle in jQuery 1.9.
  //
  // Use the first of the available functions to support jQuery <1.8.
  //
  // [1] https://github.com/jquery/jquery-migrate/blob/master/src/event.js#L25
  var dispatch = $.event.dispatch || $.event.handle;

  var special = $.event.special,
      uid1 = 'D' + (+new Date()),
      uid2 = 'D' + (+new Date() + 1);

  special.scrollstart = {
    setup: function(data) {
      var _data = $.extend({
        latency: special.scrollstop.latency
      }, data);

      var timer,
          handler = function(evt) {
            var _self = this,
                _args = arguments;

            if (timer) {
              clearTimeout(timer);
            } else {
              evt.type = 'scrollstart';
              dispatch.apply(_self, _args);
            }

            timer = setTimeout(function() {
              timer = null;
            }, _data.latency);
          };

      $(this).on('scroll', handler).data(uid1, handler);
    },
    teardown: function() {
      $(this).off('scroll', $(this).data(uid1));
    }
  };

  special.scrollstop = {
    latency: 250,
    setup: function(data) {
      var _data = $.extend({
        latency: special.scrollstop.latency
      }, data);

      var timer,
          handler = function(evt) {
            var _self = this,
                _args = arguments;

            if (timer) {
              clearTimeout(timer);
            }

            timer = setTimeout(function() {
              timer = null;
              evt.type = 'scrollstop';
              dispatch.apply(_self, _args);
            }, _data.latency);
          };

      $(this).on('scroll', handler).data(uid2, handler);
    },
    teardown: function() {
      $(this).off('scroll', $(this).data(uid2));
    }
  };
}));
