add_action('woocommerce_cart_calculate_fees', 'custom_shipping_fee');
add_action('woocommerce_checkout_update_order_review', 'custom_shipping_fee');

function custom_shipping_fee() {
    // WooCommerce sepet nesnesini alın
    if (is_admin() && !defined('DOING_AJAX')) return;
    if (WC()->cart->is_empty()) return;

    $cart_total = WC()->cart->subtotal;

    // Eğer sepet toplamı 1000₺'nin altındaysa, kargo ücretini ekle
    if ($cart_total <= 1000) {
        $shipping_fee = 30; // Kargo ücreti: 30₺ (örnek)
        WC()->cart->add_fee(__('Kargo Ücreti', 'woocommerce'), $shipping_fee);
    }
}