$(function() {
	var $menu				= $('#ei_menu > ul'),
		$menuItems			= $menu.children('li'),
		$menuItemsImgWrapper= $menuItems.children('a'),
		$menuItemsPreview	= $menuItemsImgWrapper.children('.ei_preview'),
		totalMenuItems		= $menuItems.length,
	
		ExpandingMenu 	= (function(){
			/*
				@current
				set it to the index of the element you want to be opened by default,
				or -1 if you want the menu to be closed initially
			 */
			var current				= 3,
			/*
				@anim
				if we want the default opened item to animate initialy set this to true
			 */
			anim				= true,
			/*
				checks if the current value is valid -
				between 0 and the number of items
			 */
			validCurrent		= function() {
				return (current >= 0 && current < totalMenuItems);
			},
			init				= function() {
					/* show default item if current is set to a valid index */
				if(validCurrent())
					configureMenu();

				initEventsHandler();
			},
			configureMenu		= function() {
					/* get the item for the current */
				var $item	= $menuItems.eq(current);
					/* if anim is true slide out the item */
				if(anim)
					slideOutItem($item, true, 900, 'easeInQuint');
				else{
						/* if not just show it */
					$item.css({width : '400px'})
					.find('.ei_image')
					.css({left:'0px', opacity:1});

						/* decrease the opacity of the others */
						$menuItems.not($item)
								  .children('.ei_preview')
								  .css({opacity:0.2});
				}
			},
			initEventsHandler	= function() {
					/*
					when we click an item the following can happen:
					1) The item is already opened - close it!
					2) The item is closed - open it! (if another one is opened, close it!)
					*/
				$menuItemsImgWrapper.bind('click.ExpandingMenu', function(e) {
					var $this 	= $(this).parent(),
					idx		= $this.index();

					if(current === idx) {
						slideOutItem($menuItems.eq(current), false, 1500, 'easeOutQuint', true);
						current = -1;
					}
					else{
						if(validCurrent() && current !== idx)
								slideOutItem($menuItems.eq(current), false, 250, 'jswing');

						current	= idx;
							slideOutItem($this, true, 250, 'jswing');
					}
					return false;
				});
			},
				/* if you want to trigger the action to open a specific item */
				openItem			= function(idx) {
					$menuItemsImgWrapper.eq(idx).click();
				},
				/*
				opens or closes an item
				note that "mLeave" is just true when all the items close,
				in which case we want that all of them get opacity 1 again.
				"dir" tells us if we are opening or closing an item (true | false)
				*/
			slideOutItem		= function($item, dir, speed, easing, mLeave) {
				var $ei_image	= $item.find('.ei_image'),

				itemParam	= (dir) ? {width : '400px'} : {width : '75px'},
				imageParam	= (dir) ? {left : '0px'} : {left : '75px'};

					/*
					if opening, we animate the opacity of all the elements to 0.1.
					this is to give focus on the opened item..
					*/
				if(dir)
				/*
						alternative:
						$menuItemsPreview.not($menuItemsPreview.eq(current))
										 .stop()
										 .animate({opacity:0.1}, 500);
				 */
					$menuItemsPreview.stop()
				.animate({opacity:0.3}, 1000);
				else if(mLeave)
					$menuItemsPreview.stop()
				.animate({opacity:1}, 1500);

					/* the <li> expands or collapses */
				$item.stop().animate(itemParam, speed, easing);
					/* the image (color) slides in or out */
				$ei_image.stop().animate(imageParam, speed, easing, function() {
						/*
						if opening, we animate the opacity to 1,
						otherwise we reset it.
						*/
					if(dir)
						$ei_image.animate({opacity:1}, 500);
					else
						$ei_image.css('opacity', 0.2);
				});
			};

			return {
				init 		: init,
				openItem	: openItem
			};
		})();
		
	/*
	call the init method of ExpandingMenu
	*/
	ExpandingMenu.init();

	/*
	if later on you want to open / close a specific item you could do it like so:
	ExpandingMenu.openItem(3); // toggles item 3 (zero-based indexing)
	*/

	$('#trigger_list').find('li > a').bind('click', function(e) {
		ExpandingMenu.openItem($(this).parent().index()-1);
		return false;
	});

});