/* Copyright (c) 2006 Brandon Aaron (brandon.aaron@gmail.com || http://brandonaaron.net)
 * Dual licensed under the MIT (http://www.opensource.org/licenses/mit-license.php)
 * and GPL (http://www.opensource.org/licenses/gpl-license.php) licenses.
 * 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.
 *
 * $LastChangedDate: 2007-12-20 09:02:08 -0600 (Thu, 20 Dec 2007) $
 * $Rev: 4265 $
 *
 * Version: 3.0
 * 
 * Requires: $ 1.2.2+
 */

(function(jQuery) {

jQuery.event.special.mousewheel = {
  setup: function() {
    var handler = jQuery.event.special.mousewheel.handler;
    
    // Fix pageX, pageY, clientX and clientY for mozilla
    if ( jQuery.browser.mozilla )
      jQuery(this).bind('mousemove.mousewheel', function(event) {
        jQuery.data(this, 'mwcursorposdata', {
          pageX: event.pageX,
          pageY: event.pageY,
          clientX: event.clientX,
          clientY: event.clientY
        });
      });
  
    if ( this.addEventListener )
      this.addEventListener( (jQuery.browser.mozilla ? 'DOMMouseScroll' : 'mousewheel'), handler, false);
    else
      this.onmousewheel = handler;
  },
  
  teardown: function() {
    var handler = jQuery.event.special.mousewheel.handler;
    
    jQuery(this).unbind('mousemove.mousewheel');
    
    if ( this.removeEventListener )
      this.removeEventListener( (jQuery.browser.mozilla ? 'DOMMouseScroll' : 'mousewheel'), handler, false);
    else
      this.onmousewheel = function(){};
    
    jQuery.removeData(this, 'mwcursorposdata');
  },
  
  handler: function(event) {
    var args = Array.prototype.slice.call( arguments, 1 );
    
    event = jQuery.event.fix(event || window.event);
    // Get correct pageX, pageY, clientX and clientY for mozilla
    jQuery.extend( event, jQuery.data(this, 'mwcursorposdata') || {} );
    var delta = 0, returnValue = true;
    
    if ( event.wheelDelta ) delta = event.wheelDelta/120;
    if ( event.detail     ) delta = -event.detail/3;
    if ( jQuery.browser.opera  ) delta = -event.wheelDelta;
    
    event.data  = event.data || {};
    event.type  = "mousewheel";
    
    // Add delta to the front of the arguments
    args.unshift(delta);
    // Add event to the front of the arguments
    args.unshift(event);

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

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

})(jQuery);