/*
---

name: Element.defineCustomEvent

description: Allows to create custom events based on other custom events.

authors: Christoph Pojer (@cpojer)

license: MIT-style license.

requires: [Core/Element.Event]

provides: Element.defineCustomEvent

...
*/

(function(){

[Element, Window, Document].invoke('implement', {hasEvent: function(event){
	var events = this.retrieve('events'),
		list = (events && events[event]) ? events[event].values : null;
	if (list){
		for (var i = list.length; i--;) if (i in list){
			return true;
		}
	}
	return false;
}});

var wrap = function(custom, method, extended, name){
	method = custom[method];
	extended = custom[extended];

	return function(fn, customName){
		if (!customName) customName = name;

		if (extended && !this.hasEvent(customName)) extended.call(this, fn, customName);
		if (method) method.call(this, fn, customName);
	};
};

var inherit = function(custom, base, method, name){
	return function(fn, customName){
		base[method].call(this, fn, customName || name);
		custom[method].call(this, fn, customName || name);
	};
};

var events = Element.Events;

Element.defineCustomEvent = function(name, custom){

	var base = events[custom.base];

	custom.onAdd = wrap(custom, 'onAdd', 'onSetup', name);
	custom.onRemove = wrap(custom, 'onRemove', 'onTeardown', name);

	events[name] = base ? Object.append({}, custom, {

		base: base.base,

		condition: function(event){
			return (!base.condition || base.condition.call(this, event)) &&
				(!custom.condition || custom.condition.call(this, event));
		},

		onAdd: inherit(custom, base, 'onAdd', name),
		onRemove: inherit(custom, base, 'onRemove', name)

	}) : custom;

	return this;

};

var loop = function(name){
	var method = 'on' + name.capitalize();
	Element[name + 'CustomEvents'] = function(){
		Object.each(events, function(event, name){
			if (event[method]) event[method].call(event, name);
		});
	};
	return loop;
};

loop('enable')('disable');

})();