$userid = $_SESSION["userid"];
$cart_data['error_not_logged_in'] = false;
//add product to the shopping cart
if ($productMgr->retrieveItemQtyInShoppingCart($userid, $product_id, $color) > 0) {
$addedQty = $productMgr->retrieveItemQtyInShoppingCart($userid, $product_id, $color);
$totalQty = $addedQty + $qty;
$productMgr->updateItemQty($userid, $color, $product_id, $totalQty);
$qty_update = true;
} else {
$productMgr->addProductToShoppingCart($userid, $product_id, $qty, $color);
}
$photoList = $photoMgr->getPhotos($product_id);
$photo_url = $photoList[$color];
//get the number of item in customer's shopping cart
$cart_qty = $productMgr->retrieveTotalNumberOfItemsInShoppingCart($userid);
$cart_unique_qty = $productMgr->retrieveTotalNumberOfUniqueItemsInShoppingCart($userid);
$item_qty = $productMgr->retrieveItemQtyInShoppingCart($userid, $product_id, $color);
$product_name = $productMgr->getProductName($product_id);
$cart_data['cart_qty'] = $cart_qty;
$cart_data['cart_unique_qty'] = $cart_unique_qty;
$cart_data['add_item_id'] = $product_id;
$cart_data['item_qty'] = $item_qty;
$cart_data['product_name'] = $product_name;
$cart_data['photo_url'] = $photo_url;
$cart_data['userid'] = $userid;
$cart_data['qty_update'] = $qty_update;
$cart_data['qty_to_change'] = $qty;
$cart_data['product_color'] = $color;
} else {
$cart_data['error_not_logged_in'] = true;
$_SESSION['temp_product_id_to_cart'] = $product_id;
