在Woocommerce购物车中免费添加现有的付费产品

Question

对于我的网上商店，我想发起一个折扣活动，在这个活动中，当购物车达到一定的总额时，我的客户免费获得正常付款的产品。无论购物车的价值多少，他们获得的产品仍然可用。

我不想创建该产品的变体，也不想创建一个新产品。我希望看到免费产品链接到现有的付费产品，但是购物车中的价格降低了（可能还有不同的标题）。

为更加清晰起见，我添加了一张图片作为演示。我在演示中将限值设置为60英镑。

有人知道我如何用PHP完成这项工作吗？我已经编写了以下代码，但这仅有助于将产品添加到购物车中。

# First of all, let us hook into the cart caclulation method.
add_action( 'woocommerce_after_calculate_totals', 'add_free_product_to_cart');

# This function will be responsible for the add/remove item from the cart, depending on the total value.
function add_free_product_to_cart() {
    # We need this global WooCommerce variable in order to access the cart.
    global $woocommerce;

    ## SETTINGS ##
    $settings['product_id'] = 2981; // Change me to the specific product id you want to add to the cart.    
    $settings['cart_limit'] = 60; // Change me to set the specfic threshold.

    ## Some local variables we need in order to make this work ##
    $found = false;

    # Check if there are any items in the cart.
    if (sizeof($woocommerce->cart->get_cart()) > 0)
    {
        # There are items in the cart. Lets loop trough them one by one and check for our specific product id.
        foreach ($woocommerce->cart->get_cart() as $cart_item_key => $values)
        {
            $product_id_in_cart = $values['data']->get_id();

            # We found the specific product id in the cart.
            if ($product_id_in_cart == $settings['product_id'])
            {
                # Lets check if cart total has been changed in the meantime. We need to remove the product if the cart total is below the limit.
                if ($woocommerce->cart->total < $settings['cart_limit'])
                {
                    # Remove the product from the cart.
                    $woocommerce->cart->remove_cart_item($cart_item_key);
                }

                # We found our specific product id, we don't need to run more code at this point.
                $found = true;
                break;
            }
        }

        # The specific product id has not been found, lets add it to the cart if the total has reached the limit.
        if (!$found && $woocommerce->cart->total >= $settings['cart_limit'])
        {
            $woocommerce->cart->add_to_cart($settings['product_id']);
        }
    }
}