// homePageFunctions.js

	var viewOnBuy = "ProductDisplayView";
	var viewOnError = "ProductDisplayErrorView";
	
	function UpdateShopCart(frm) {	
		var newQuantity = frm.quantity.value;
		var productId = frm.productId.value;
		var orderItemId = getOrderItemId(productId);
				
		updateBasketExtraURLParams(frm);
		
		if( orderItemId == null ) {
			buyProduct(productId, newQuantity, viewOnBuy);
		}
		else {
			updateQuantity(orderItemId, newQuantity, viewOnBuy)		
		}
	}

	function getOrderItemId(productId) {
		var orderItemId = null;
		var orderItem = ORDER_ITEMS.getItemByProductId(productId);
		
		if( orderItem != null ) {
			orderItemId = orderItem.id;
		}
		
		return orderItemId;
	}
	
	// additional parameters required in URL when updating basket
	// so that category display page can be redrawn
	function updateBasketExtraURLParams(frm) {
		BasketExtraUrlParams = new Array();
	
		BasketExtraUrlParams[BasketExtraUrlParams.length] = "errorViewName=" + viewOnError;
		BasketExtraUrlParams[BasketExtraUrlParams.length] = "catEntryId=" + frm.catEntryId.value;
		BasketExtraUrlParams[BasketExtraUrlParams.length] = "productId=" + frm.productId.value;
			
	}