Fee for COD

add_action( 'woocommerce_cart_calculate_fees', 'mx_checkout_fee_for_cod' );

function mx_checkout_fee_for_cod() {
    $chosen_gateway = WC()->session->get( 'chosen_payment_method' );
    $chosen_methods = WC()->session->get( 'chosen_shipping_methods' );
    $chosen_shipping = $chosen_methods[0];
     if ( $chosen_gateway == 'cod' && 0 === strpos( $chosen_shipping, 'mx_local_shipping' )){
      WC()->cart->add_fee( 'Naknada za plaćanje pouzećem', 0 );
   }
   else {
        if ( $chosen_gateway == 'cod'){
      WC()->cart->add_fee( 'Naknada za plaćanje pouzećem', 6 );
    }
    }
}

add_action( 'woocommerce_review_order_before_payment', 'mx_refresh_checkout_on_payment_method_change' );

function mx_refresh_checkout_on_payment_method_change(){
    ?>
    <script type="text/javascript">
        (function($){
            $( 'form.checkout' ).on( 'change', 'input[name^="payment_method"]', function() {
                $('body').trigger('update_checkout');
            });
        })(jQuery);
    </script>
    <?php
}