Disable Barion if shipping method is free shipping

//Disable Payment Gateway For Specific Shipping Method
 
add_filter( 'woocommerce_available_payment_gateways', 'wpninja_gateway_disable_shipping_326' );
 
function wpninja_gateway_disable_shipping_326( $available_gateways ) {
 
    global $woocommerce;
     
    if ( !is_admin() ) {
         
        $chosen_methods = WC()->session->get( 'chosen_shipping_methods' );
         
        $chosen_shipping = $chosen_methods[0];
         
        if ( isset( $available_gateways['cod'] ) && 0 === strpos( $chosen_shipping, 'free_shipping' ) ) {
            unset( $available_gateways['barion'] );
        }
        
    }
     
return $available_gateways;
     
}