Add a fee based on shipping method and payment method in Woocommerce - php

Question

I need to apply an additional fee when a customer can place an order with free shipping, but wants to select COD payment.
So, Free Shipping + COD payment => fee.
I tried unsuccessfully the following piece of code. Where am I wrong?
add_action( 'woocommerce_cart_calculate_fees','cod_fee' );
function cod_fee() {
global $woocommerce;
if ( is_admin() && ! defined( 'DOING_AJAX' ) )
return;
$chosen_gateway = WC()->session->chosen_payment_method;
$chosen_methods = WC()->session->get( 'chosen_shipping_methods' );
$chosen_shipping = $chosen_methods[0];
$fee = 19;
if ( $chosen_shipping == 'free_shipping' && $chosen_gateway == 'cod' ) {
WC()->cart->add_fee( 'Spese per pagamento alla consegna', $fee, false, '' );
}
}

Answer 1

There is a mistake in your code and some additional code is needed. Try the following code that will add a specific fee when chosen payment method is Cash on delivery (cod) and when chosen shipping methods is "Free shipping":
// Add a conditional fee
add_action( 'woocommerce_cart_calculate_fees', 'add_cod_fee', 20, 1 );
function add_cod_fee( $cart ) {
if ( is_admin() && ! defined( 'DOING_AJAX' ) )
return;
## ------ Your Settings (below) ------ ##
$your_payment_id = 'cod'; // The payment method
$your_shipping_method = 'free_shipping'; // The shipping method
$fee_amount = 19; // The fee amount
## ----------------------------------- ##
$chosen_payment_method_id = WC()->session->get( 'chosen_payment_method' );
$chosen_shipping_method_id = WC()->session->get( 'chosen_shipping_methods' )[0];
$chosen_shipping_method = explode( ':', $chosen_shipping_method_id )[0];
if ( $chosen_shipping_method == $your_shipping_method
&& $chosen_payment_method_id == $your_payment_id ) {
$fee_text = __( "Spese per pagamento alla consegna", "woocommerce" );
$cart->add_fee( $fee_text, $fee_amount, false );
}
}
// Refresh checkout on payment method change
add_action( 'wp_footer', 'refresh_checkout_script' );
function refresh_checkout_script() {
// Only on checkout page
if( is_checkout() && ! is_wc_endpoint_url('order-received') ) :
?>
<script type="text/javascript">
jQuery(function($){
// On payment method change
$('form.woocommerce-checkout').on( 'change', 'input[name="payment_method"]', function(){
// Refresh checkout
$('body').trigger('update_checkout');
});
})
</script>
<?php
endif;
}
Code goes in functions.php file of your active child theme (or active theme). tested and works.