/** 
  * SWFWheel - remove dependencies of mouse wheel on each browser. 
  * 
  * Copyright (c) 2008 - 2009 Spark project (www.libspark.org) 
  * 
  * Dual licensed under the MIT (MIT-LICENSE.txt) 
  * and GPL (GPL-LICENSE.txt) licenses. 
  */ 
(function () 
 { 
     // do nothing if already defined `SWFWheel`. 
     if (window.SWFWheel) return; 
  
     var win = window, 
         doc = document, 
         nav = navigator; 
  
     var SWFWheel = window.SWFWheel = function (id) 
     { 
         this.setUp(id); 
         if (SWFWheel.browser.msie) 
             this.bind4msie(); 
         else 
             this.bind(); 
     }; 
  
     SWFWheel.prototype = { 
         setUp: function (id) 
         { 
             var el = SWFWheel.retrieveObject(id); 
             if (el.nodeName.toLowerCase() == 'embed' || SWFWheel.browser.safari) 
                 el = el.parentNode; 
             this.target = el; 
             this.eventType = SWFWheel.browser.mozilla ? 'DOMMouseScroll' : 'mousewheel'; 
         }, 
  
         bind: function () 
         { 
             this.target.addEventListener(this.eventType, function (evt) 
             { 
                 var target, 
                     name, 
                     delta = 0; 
                 // retrieve real node from XPCNativeWrapper. 
                 if (/XPCNativeWrapper/.test(evt.toString())) 
                 { 
                     // FIXME: embed element has no id attributes on `AC_RunContent`. 
                     var k = evt.target.getAttribute('id') || evt.target.getAttribute('name'); 
                     if (!k) return; 
                     target = SWFWheel.retrieveObject(k); 
                 } 
                 else 
                 { 
                     target = evt.target; 
                 } 
                 name = target.nodeName.toLowerCase(); 
                 // check target node. 
                 if (name != 'object' && name != 'embed') return; 
                 // kill process. 
                 if (!target.checkBrowserScroll()) 
                 { 
                     evt.preventDefault(); 
                     evt.returnValue = false; 
                 } 
                 // execute wheel event if exists. 
                 if (!target.triggerMouseEvent) return; 
                 // fix delta value. 
                 switch (true) 
                 { 
                     case SWFWheel.browser.mozilla: 
                         delta = -evt.detail; 
                         break; 
  
                     case SWFWheel.browser.opera: 
                         delta = evt.wheelDelta / 40; 
                         break; 
  
                     default: 
                         //  safari, stainless, opera and chrome. 
                         delta = evt.wheelDelta / 80; 
                         break; 
                 } 
                 target.triggerMouseEvent(delta); 
             }, false); 
         }, 
  
         bind4msie: function () 
         { 
             var _wheel, 
                 _unload, 
                 target = this.target; 
  
             _wheel = function () 
             { 
                 var evt = win.event, 
                    delta = 0, 
                    name = evt.srcElement.nodeName.toLowerCase(); 
  
                 if (name != 'object' && name != 'embed') return; 
                 if (!target.checkBrowserScroll()) 
                     evt.returnValue = false; 
                 //  will trigger when wmode is `opaque` or `transparent`. 
                 if (!target.triggerMouseEvent) return; 
                 delta = evt.wheelDelta / 40; 
                 target.triggerMouseEvent(delta); 
             }; 
             _unload = function () 
             { 
                 target.detachEvent('onmousewheel', _wheel); 
                 win.detachEvent('onunload', _unload); 
             }; 
             target.attachEvent('onmousewheel', _wheel); 
             win.attachEvent('onunload', _unload); 
         } 
     }; 
  
     //  utilities. ------------------------------------------------------------ 
     SWFWheel.browser = (function (ua) 
     { 
         return { 
                 version: (ua.match(/.+(?:rv|it|ra|ie)[\/:\\s]([\\d.]+)/)||[0,'0'])[1], 
             chrome: /chrome/.test(ua), 
             stainless: /stainless/.test(ua), 
             safari: /webkit/.test(ua) && !/(chrome|stainless)/.test(ua), 
             opera: /opera/.test(ua), 
             msie: /msie/.test(ua) && !/opera/.test(ua), 
             mozilla: /mozilla/.test(ua) && !/(compatible|webkit)/.test(ua) 
         } 
     })(nav.userAgent.toLowerCase()); 
  
     SWFWheel.join = function (id) 
     { 
         var t = setInterval(function () 
         { 
             if (SWFWheel.retrieveObject(id)) 
             { 
                clearInterval(t); 
                 new SWFWheel(id); 
             } 
         }, 0); 
     }; 
  
     SWFWheel.force = function (id) 
     { 
         if (SWFWheel.browser.safari||SWFWheel.browser.stainless) return true; 
  
         var el = SWFWheel.retrieveObject(id), 
             name = el.nodeName.toLowerCase(); 
  
         if (name == 'object') 
         { 
             var k, v, 
                 param, 
                 params = el.getElementsByTagName('param'), 
                 len = params.length; 
  
             for (var i=0; i<len; i++) 
             { 
                 param = params[i]; 
                 //  FIXME: getElementsByTagName is broken on IE? 
                 if (param.parentNode != el) continue; 
  
                 k = param.getAttribute('name'); 
                 v = param.getAttribute('value') || ''; 
                 if (/wmode/i.test(k) && /(opaque|transparent)/i.test(v)) return true; 
            } 
        } 
         else if (name == 'embed') 
         { 
             return /(opaque|transparent)/i.test(el.getAttribute('wmode')); 
         } 
         return false; 
     }; 
  
     SWFWheel.retrieveObject = function (id) 
     { 
         var el = doc.getElementById(id); 
         //  FIXME: fallback for `AC_FL_RunContent`. 
        if (!el) 
         { 
            var nodes = doc.getElementsByTagName('embed'), 
                len = nodes.length; 
  
             for (var i=0; i<len; i++) 
             { 
                 if (nodes[i].getAttribute('name') == id) 
                 { 
                     el = nodes[i]; 
                     break; 
                 } 
             } 
         } 
         return el; 
    }; 

})();