/*! Copyright (c) 2010 Brandon Aaron (http://brandonaaron.net)
 * Licensed under the MIT License (LICENSE.txt).
 *
 * Thanks to: http://adomas.org/javascript-mouse-wheel/ for some pointers.
 * Thanks to: Mathias Bank(http://www.mathias-bank.de) for a scope bug fix.
 * Thanks to: Seamus Leahy for adding deltaX and deltaY
 *
 * Version: 3.0.4
 *
 * Requires: 1.2.2+
 *
 * Usage:
 *
 *  // using bind
 * $('#my_elem').bind('mousewheel', function(event, delta) {
 *     console.log(delta);
 * });
 *
 * // using the event helper
 * $('#my_elem').mousewheel(function(event, delta) {
 *     console.log(delta);
 * });
 *
 */

(function($) {
  var types = ['DOMMouseScroll', 'mousewheel'];
  $.event.special.mousewheel = {
    setup: function() {
      if ( this.addEventListener ) {
        for ( var i=types.length; i; ) {
          this.addEventListener( types[--i], handler, false );
        }
      } else {
        this.onmousewheel = handler;
      }
    },

    teardown: function() {
      if ( this.removeEventListener ) {
        for ( var i=types.length; i; ) {
          this.removeEventListener( types[--i], handler, false );
        }
      } else {
        this.onmousewheel = null;
      }
    }
  };

  $.fn.extend({
    mousewheel: function(fn) {
      return fn ? this.bind("mousewheel", fn) : this.trigger("mousewheel");
    },

    unmousewheel: function(fn) {
      return this.unbind("mousewheel", fn);
    }
  });

  function handler(event) {
    var orgEvent = event || window.event, args = [].slice.call( arguments, 1 ), delta = 0, returnValue = true, deltaX = 0, deltaY = 0;
    event = $.event.fix(orgEvent);
    event.type = "mousewheel";

    // Old school scrollwheel delta
    if ( event.wheelDelta ) { delta = event.wheelDelta/120; }
    if ( event.detail   ) { delta = -event.detail/3; }

    // New school multidimensional scroll (touchpads) deltas
    deltaY = delta;

    // Gecko
    if ( orgEvent.axis !== undefined && orgEvent.axis === orgEvent.HORIZONTAL_AXIS ) {
      deltaY = 0;
      deltaX = -1*delta;
    }

    // Webkit
    if ( orgEvent.wheelDeltaY !== undefined ) { deltaY = orgEvent.wheelDeltaY/120; }
    if ( orgEvent.wheelDeltaX !== undefined ) { deltaX = -1*orgEvent.wheelDeltaX/120; }

    // Add event and delta to the front of the arguments
    args.unshift(event, delta, deltaX, deltaY);

    return $.event.handle.apply(this, args);
  }
})(jQuery);