//sparkl javascript library
//February 2008
//original code Neil J Anderson
//rubbish about: http://neilanderson.freehostia.com/
//version 0.1

/*

DOCUMENTATION

  This is the sparkl core module, required by most of the other modules, anything that could reasonably be required by more than one module should be added here.

  Examples would be a mixin clas,. general class methods: extend, augment, clone.

  I've put the event attaching removing stuff directly onto the namespace as they're probably going to be used by most modules.

  nja - 2008-02-06



TO DO / REVISION HISTORY



*/

/*
CORE MODULE


CONTENTS

 * sparkl namespace
 * event handling
 
*/

//namespace
var sparkl = {};

/*

EVENT HANDLING

  PROPERTIIES
	
	* cache -- events cache for IE

  GENERAL METHODS
	
	* load -- attach function to window's load
	* unload -- attach function to window's unload
  * add -- attach an event to an element
	* remove -- detach an event
	
	FUNCTION METHODS
	
	called by attaned functions
	
	* stop -- stops event bubbling
  * prevent -- prevent default behaviour
	
	CLEANUP
	
	* cleanup
	
	a private method automatically called when a page unloads
	which detaches all added events.
	This prevents memory leaks in IE

*/

//EVENTS CODE

//PROPERTIES

//ie event cache
sparkl.cache = [];

//METHODS

//add an event handler to the window when load fires
sparkl.load = function(){
  if (window.addEventListener){ //w3c DOM model
    return load = function(funct, capture){
      window.addEventListener('load', funct, capture);	 
    };
  }
  else if(window.attachEvent){
    return load = function(funct){
      window.attachEvent('onload', funct);
    };
  };
}();

//unload event handler
sparkl.unload = function(){
  if (window.addEventListener){ //w3c DOM model
      return unload = function(funct, capture){
      window.addEventListener('unload', funct, capture);	 
    };
  }
  else if(window.attachEvent){
    return unload = function(funct){
      window.attachEvent('onunload', funct);
    };
  };
}();

//add event
sparkl.add=(function(){
  var i = 0;
  if (window.addEventListener){ //w3c DOM model
    return add = function(el, typ, funct, capture){
      el.addEventListener(typ, funct, capture);	 
    };
  }
  else if (window.attachEvent){ //IE DOM model
    return add = function(el, typ, funct){ 
      i++;
      var handle = 'fx' + typ + i;//unique id
      if(el.tagName){
        el.setAttribute(handle,'on');
        var fn = function(){
          var trg = window.event.srcElement;//null for window
          var tag = handle;
          while (trg.getAttribute(tag)!='on'){
            trg = trg.parentNode;//walk up dom
          };
          funct.call(trg, window.event);
				};	
				sparkl.event.cache.push([el, typ, handle, funct, fn]);
      }
			else{
			  fn = funct;
			};
      el.attachEvent('on' + typ, fn);
    };
  };
})();


//remove an event
sparkl.remove = function(){
  if (window.removeEventListener){
    return remove = function(el, typ, funct, capture){
		  el.removeEventListener(typ, funct, capture);
		};
	}
	else if(window.detachEvent){
    return remove = function(el, typ, funct){
		  var eventCache = sparkl.cache;
		  for(var i= eventCache.length-1; i>=0; i--){
				if(eventCache[i][0] == el
				 && eventCache[i][1] == typ 
				 && el.getAttribute(eventCache[i][2])
				 && funct === eventCache[i][3]){
					  el.detachEvent('on'+typ, eventCache[i][4]);
				    eventCache.splice(i,1);
				};
			};
		};
	};
}();

//FUNCTION METHODS
//called by functions
//lazy load

//	you have to get the event -- f(e){sparkl.prevent(e);}

//stop bubbling
sparkl.stop = function(e){
  if(e.stopPropagation){
    e.stopPropagation();//first call stop
      stop = function(e){
        e.stopPropagation();
    };
  }
  else{
    e.cancelBubble = true;
    stop = function(e){
      e.cancelBubble = true;
    };
  };
};

//prevent default behavior
sparkl.prevent = function(e){
  if(e.preventDefault){
    e.preventDefault();//first call prevent
    prevent = function(e){
      e.preventDefault();
    };
  }
  else{
    e.returnValue = false;
    prevent = function(e){
      e.returnValue = false;
    };
  };
};

//CLEANUP

//unattach all events
//used to prevent IE memory leaks
sparkl.cleanup = function(){
  var eventCache = sparkl.cache
  for(var i = eventCache.length - 1; i>=0; i--){
	  if(window.detachEvent){
      eventCache[i][0].detachEvent('on'+eventCache[i][1],eventCache[i][4]);
		};	
	};
};

//call the cleanup function
sparkl.unload(sparkl.cleanup);