Wordpress/Woocommerce相关问题。

我想在添加某个类别的物品后，通过编程将“免费礼物”添加到购物车中。这种免费礼物实际上也是一种他们可以单独从商店购买的产品，但当它与上述类别的商品组合时，将作为免费礼物。

到目前为止，我有一个工作代码，一旦添加了特定类别的项目，就可以添加额外的产品。但我不知道如何在购物车中将此商品的价格设置为零。

/*
* Automatically adding the product to the cart.
*/

function aaptc_add_product_to_cart( $item_key, $product_id ) {

    $product_category_id    = 92; // set category id

    $product_cats_ids   = wc_get_product_term_ids( $product_id, \'product_cat\' );

    if ( ! is_admin() && in_array( $product_category_id, $product_cats_ids ) ) {
        $free_product_id = 7506;  // Product Id of the free product which will get added to cart
        $found      = false;

        //check if product already in cart
        if ( sizeof( WC()->cart->get_cart() ) > 0 ) {
            foreach ( WC()->cart->get_cart() as $cart_item_key => $values ) {
                $_product = $values[\'data\'];
                if ( $_product->get_id() == $free_product_id )
                    $found = true;
                
            }
            // if product not found, add it
            if ( ! $found )
                WC()->cart->add_to_cart( $free_product_id );
                        function return_custom_price($price, $product) {
                            $myPrice = 0;

                            global $current_user;
                            $price = $myPrice;
                            $post_id = $post->$free_product_id;
                            return $price;
                        }
                        add_filter(\'woocommerce_get_price\', \'return_custom_price\', 10, 2);
                        
        } else {
            // if no products in cart, add it
            WC()->cart->add_to_cart( $free_product_id );
                        function return_custom_price($price, $product) {
                            $myPrice = 0;

                            global $current_user;
                            $price = $myPrice;
                            $post_id = $post->$free_product_id;
                            return $price;
                        }
                        add_filter(\'woocommerce_get_price\', \'return_custom_price\', 10, 2);
        }        
    }    
}

add_action( \'woocommerce_add_to_cart\', \'aaptc_add_product_to_cart\', 10, 2 );

我很确定代码片段的以下部分在编程上是错误的，但我不确定如何实现免费添加产品的零价格。

function return_custom_price($price, $product) {
                            $myPrice = 0;

                            global $current_user;
                            $price = $myPrice;
                            $post_id = $post->$free_product_id;
                            return $price;
                        }
add_filter(\'woocommerce_get_price\', \'return_custom_price\', 10, 2);