var shoppingCart;
var shoppingCartFinishedLoadingCallback;

function loadShoppingCart(finishedLoadingCallback) {
	var xmlHttpRequest;
	
	shoppingCartFinishedLoadingCallback = finishedLoadingCallback;

	try {
		xmlHttpRequest = new XMLHttpRequest();
	} catch(e) {
		xmlHttpRequest = new ActiveXObject("Msxml2.XMLHTTP");
	}
	
	xmlHttpRequest.onreadystatechange = function() {
		if(xmlHttpRequest.readyState != 4) return;
		
		loadShoppingCartFinished(xmlHttpRequest);
	};
	
	xmlHttpRequest.open("GET", "/shoppingcart/getShoppingCart.php", true);
	xmlHttpRequest.send(null);
}

function loadShoppingCartFinished(xmlHttpRequest) {
	var xml = xmlHttpRequest.responseXML;
	var rootNode = xml.firstChild;
	var node;
	var ids;
	var element;
	var i;
	
	shoppingCart = new Object();
	shoppingCart['swf'] = new Array();
	shoppingCart['source'] = new Array();
	
	for(node=rootNode.firstChild;node;node=node.nextSibling) {
		switch(node.nodeName) {
		case 'SWF':
			ids = node.attributes.getNamedItem('ids').nodeValue.split(',');
			for(i=0;i<ids.length;i++) {
				shoppingCart['swf'][ids[i]] = true;
			}
			break;
		case 'SOURCE':
			ids = node.attributes.getNamedItem('ids').nodeValue.split(',');
			for(i=0;i<ids.length;i++) {
				shoppingCart['source'][ids[i]] = true;
			}
			break;
		}
	}
	
	shoppingCartFinishedLoadingCallback();
}

function addToRemoveFromCart(type, id, button) {
	var xmlHttpRequest;

	try {
		xmlHttpRequest = new XMLHttpRequest();
	} catch(e) {
		xmlHttpRequest = new ActiveXObject("Msxml2.XMLHTTP");
	}
	
	if(shoppingCart[type][id]) {
		shoppingCart[type][id] = false;
		xmlHttpRequest.open("GET", "/shoppingcart/removeFromCart.php?type=" + type + "&id=" + id, true);
		
	} else {
		shoppingCart[type][id] = true;
		xmlHttpRequest.open("GET", "/shoppingcart/addToCart.php?type=" + type + "&id=" + id, true);
	}
	
	xmlHttpRequest.send(null);
	
	updateCartButton(type, id, button);
}

function updateCartButton(type, id, button) {
	var element = document.getElementById(button);
	var className;
	var index;
	
	if(!element) return;
	
	className = element.className;
	
	if((index = className.indexOf(' shoppingCartRemoveFromCartButton')) != -1) {
		className = className.substr(0, index);
	} else if((index = className.indexOf(' shoppingCartAddToCartButton')) != -1) {
		className = className.substr(0, index);
	}
	
	element.className = className + (shoppingCart[type][id] ? ' shoppingCartRemoveFromCartButton' : ' shoppingCartAddToCartButton');
}