Code-Snippets-Functions/Execute a function on a child site/WooCommerce/adding-a-fee-to-product-variation-passed-to-cart.txt

// Define variation price with fee
add_filter( 'woocommerce_add_cart_item_data', 'define_variation_price_with_fee', 10, 3 );
function define_variation_price_with_fee( $cart_item_data, $product_id, $variation_id ) {   
    // Only for product variations
    if ( $variation_id > 0 ) {
        // Define the fee amount to be added
        $variation_fee = 20; 
        // Get an instance of the product variation object
        $variation     = wc_get_product( $variation_id ); 
        // Add price with fee as custom cart item data
        $cart_item_data['price_with_fee'] = $variation->get_price() + $variation_fee;
    }
    return $cart_item_data;
}


// Display variation price with fee html (cart, mini-cart and checkout)
add_filter( 'woocommerce_cart_item_price', 'display_variation_price_with_fee', 10, 2 );
function display_variation_price_with_fee($price, $cart_item) {
    // Check item for the price with fee
    if ( isset($cart_item['price_with_fee']) ) {
        // Set the price with fee in arguments
        $args = array('price' => floatval($cart_item['price_with_fee']));

        if ('incl' === get_option('woocommerce_tax_display_cart')) {
            $product_price = wc_get_price_including_tax($cart_item['data'], $args);
        } else {
            $product_price = wc_get_price_excluding_tax($cart_item['data'], $args);
        }
        return wc_price($product_price);
    }
    return $price;
}

// Set variation price with fee (when order is submitted)
add_action( 'woocommerce_before_calculate_totals' , 'set_variation_price_with_fee' );
function set_variation_price_with_fee( $cart ) { 
    if ( is_admin() && !defined('DOING_AJAX') )
        return;

    // Loop through cart items
    foreach ( $cart->get_cart() as $item ) {
        // Check items for the price with fee
        if ( isset($item['price_with_fee']) ) {
            // Set the price with fee
            $item['data']->set_price($item['price_with_fee']);
        }
    }
}