使用 php（WooCommerce 4.5.1）根据产品的类别和数量添加购物车费用

Question

I've tried searching for an answer to this but most of the code is old or not exactly what I'm looking for. Here is the scenario - when people order digital image rights from our store, they must pay for it's usage as well as a copy fee. The usage fee is variable based on several factors and non-taxable - this would be the product added to the cart. The copy fee is a fixed, taxable, cost per image. I want this to be automatically added to my cart whenever an product from the 'images' category is added.

I found code on WPFactory that adds a fee based on category that works well.

add_action( 'woocommerce_cart_calculate_fees', 'wpf_wc_add_cart_fees_by_product_category' );
if ( ! function_exists( 'wpf_wc_add_cart_fees_by_product_category' ) ) {
    /**
     * wpf_wc_add_cart_fees_by_product_category.
     */
    function wpf_wc_add_cart_fees_by_product_category( $cart ) {
        // You need to enter your fees here, in `category slug` => `fee amount` format
        $fees = array(
            'images'    => 25,
        );
        foreach ( $cart->get_cart() as $cart_item_key => $values ) {
            $product_categories = get_the_terms( $values['product_id'], 'product_cat' );
            if ( $product_categories && ! is_wp_error( $product_categories ) ) {
                $product_categories = wp_list_pluck( $product_categories, 'slug' );
                foreach ( $product_categories as $product_category ) {
                    if ( ! empty( $fees[ $product_category ] ) ) {
                        $name      = 'Digital Image Copy Fee'
                        $amount    = $fees;
                        $taxable   = true;
                        $tax_class = '';
                        $cart->add_fee( $name, $amount, $taxable, $tax_class );
                    }
                }
            }
        }
    }
}

The problem is, it only adds the fee once and I need it to multiply the fee based on the total quantity of items from the category in the cart. I've attempted to calculate $qty and multiply $fee by $qty but my php is incredibly rusty and I have not been successful. Any help would be much appreciated.

Answer 1

Here is the solution:

add_action( 'woocommerce_cart_calculate_fees', 'wpf_wc_add_cart_fees_by_product_category', 10, 1 );
function wpf_wc_add_cart_fees_by_product_category( $cart ) {

    $product_cat_id = 119; // set "image" cat id
    $total_qty = 0; // initialize qty products
    $fee = 25; // set fee amount

    foreach ( $cart->get_cart() as $cart_item ) {
        $product_id = $cart_item['product_id'];
        // get all category ids by product id
        $categories = wp_get_post_terms( $product_id, 'product_cat', array( 'fields' => 'ids' ) );
        // if product has "image" category
        if ( in_array( $product_cat_id, $categories ) )  {
            // get quantity
            $total_qty += $cart_item['quantity'];
        }
    }
    
    if ( $total_qty > 0 ) {
        $tax = true; // set "false" for no tax
        $cart->add_fee( __( "Digital Image Copy Fee", "woocommerce" ), $fee * $total_qty, $tax ); // add custom fee
    }

}

The code goes into your theme's functions.php file and it works.