PHP function for Woocommerce: change SKU on country?

Hey there!

i have a webshop and i sell to Switzerland CH and Germany DE. now i have connected that shop to my ERP Tool and so far all is working fine.

I now need to have a function which adds a prefix to the SKU, based on the country of purchase. so for instance:

• a customer buys a product with SKU: 1234
• his delivery address is germany
• the function should add a prefix DE- to the SKU and write this into the order. so it says SKU: DE-1234
• how do i do this?

Tryed with my following php snipped, but it is not working:::

add_action(?woocommerce_new_order‘, ?customize_sku_based_on_shipping_country‘, 10, 1);

function customize_sku_based_on_shipping_country($order_id) {
// Get the order
$order = wc_get_order($order_id);

// Get the shipping country
$shipping_country = $order->get_shipping_country();

// Define prefixes based on countries
$prefixes = array(
    'DE' => 'DE-', // Prefix for Germany
    'AT' => 'AT-', // Prefix for Austria
    // Add more countries and prefixes as needed
);

// Check if there is a prefix for the shipping country
if (isset($prefixes[$shipping_country])) {
    // Iterate over the order items and add the prefix to the SKU
    foreach ($order->get_items() as $item_id => $item) {
        $product     = $item->get_product();
        $current_sku = $product->get_sku();
        $new_sku     = $prefixes[$shipping_country] . $current_sku;

        // Update the SKU of the order item
        $item->set_props(array('sku' => $new_sku));
        $item->save();
    }
}

Erweitern

}

any ideas??

Thanks a lot! Mike