Display custom text on WooCommerce Order Received page if specific coupons are used

Question

I'm attempting to display a custom thank you message on the Woocommerce order received page if one of three specific coupon codes are used during checkout.

Our Woocommerce version is 2.6.11.

I've tried a few variations of the below code but cannot get it working, am I doing something incorrectly?

//show custom coupon thankyou
function coupon_thankyou($order_id) {
    $coupon_id = '1635';
    $order = wc_get_order($order_id);
    foreach( $order->get_items('coupon') as $coupon_item ){
        if( $coupon_item->get_code() = $coupon_id ){
            echo '<p>This is an custom thank you.</p>';
        }
    }
}
add_action('woocommerce_thankyou','coupon_thankyou');

Answer 1

There is a mistake in your IF statement condition where = has to be replaced with == or ===. Also with coupons, you need to use the coupon code slug (but not the post ID).

To display a message on Order received page better use woocommerce_thankyou_order_received_text filter hook, this way (for Woocommerce 3+):

// On "Order received" page (add a message)
add_filter( 'woocommerce_thankyou_order_received_text', 'thankyou_applied_coupon_message', 10, 2 );
function thankyou_applied_coupon_message( $text, $order ) {
    $coupon_code = '1635'; // coupon code name

    foreach( $order->get_items('coupon') as $coupon ){
        if( $coupon->get_code() === $coupon_code ){
            $text .= '<p>'.__("This is an custom thank you.").'</p>';
        }
    }
    return $text;
}

Code goes in function.php file of your active child theme (or active theme). It should works now.

---

Updated

For the versions of Woocommerce before 3.0, you should use use the following instead:

// On "Order received" page (add a message)
add_action( 'woocommerce_thankyou', 'thankyou_applied_coupon_message', 10, 1 );
function thankyou_applied_coupon_message( $order_id ) {
    $coupon_code = '1635'; // coupon code name

    $order = wc_get_order( $order_id );

    foreach( $order->get_items('coupon') as $coupon ){
        if( $coupon['name'] === $coupon_code ){
            echo '<p>'.__("This is an custom thank you.").'</p>';
        }
    }
}

Code goes in function.php file of your active child theme (or active theme). Tested and works.