var DropDownMenu = new Class({
	initialize: function(menuElement) {
		this.menu = menuElement;
		this.id = menuElement.id;
		this.duration = 1200;
		this.buttons = [];
		
		$A(this.menu.getElementsByTagName('li')).each(
			function(li) {
				if(li.parentNode == menuElement) { this.buttons.push($(li)); }
			}.bind(this)
		);
		this.submenus = $A(this.menu.getElementsByTagName('ul'));
		
		this.submenus.each(
			function(submenu) {
				submenu = $(submenu);
				submenu.setStyle('display','');
				submenu.originalHeight = submenu.offsetHeight;
				submenu.effect = new Fx.Style(submenu, 'height',{ duration: this.duration, transition:Fx.Transitions.quartOut });
				submenu.effect.set(0);
			}.bind(this)
		);
		
		this.buttons.each(
			function(button) {
				button.addEvent('mouseover',this.expand.bindAsEventListener(this));
				button.addEvent('mouseout', this.collapse.bindAsEventListener(this));
			}.bind(this)
		);
	},
	
	findButton: function(element) {
		var button = false;
		while(element.parentNode) {
			if(this.buttons.test(element)) { button = element; }
			element = element.parentNode;
		}
		return button;
	},
	
	findSubmenu: function(element) {
		var button = this.findButton(element);
		var submenu = button.getElementsByTagName('ul')[0];
		return submenu;
	},
	
	expand: function(event) {
		var submenu = this.findSubmenu(event.target || event.srcElement);
		if(submenu) {
			submenu.effect.clearTimer();
			submenu.effect.start(submenu.originalHeight);
		}
	},
	
	collapse: function(event) {
		var submenu = this.findSubmenu(event.target || event.srcElement);
		if(submenu) {
			submenu.effect.clearTimer();
			submenu.effect.start(0);
		}
	}
});

window.addEvent('domready',function(){
	if(DropDownMenu && $('navigation')) {
		var menu = new DropDownMenu($('navigation'));
	}
});