public function addProduct($data, $user = null, $locale = null)
    {
        //TODO: locale
        // get cart
        $cart = $this->getUserCart($user, $locale, null, true);
        // define user-id
        $userId = $user ? $user->getId() : null;

        $item = $this->orderManager->addItem($data, $locale, $userId, $cart);

        $this->validateIfItemProductActive($item->getEntity());

        $this->orderManager->updateApiEntity($cart, $locale);

        return $cart;
    }