AffiliateWP — Block Referrals for Existing Customers

/**

 * Block AffiliateWP referrals for existing WooCommerce customers.

 *

 * Allows referral commissions only on a customer's first-ever order.

 * Any returning customer will not generate a referral, regardless of

 * affiliate links clicked or coupons used.

 *

 * Install via WPCode > Code Snippets > Add Snippet > PHP Snippet > Run Everywhere.

 */

function my_affwp_no_referral_for_existing_customers( $allow, $referral_args ) {

    if ( ! function_exists( 'wc_get_order' ) || ! $allow ) {

        return $allow;

    }

    $order_id = ! empty( $referral_args['reference'] ) ? absint( $referral_args['reference'] ) : 0;

    if ( ! $order_id ) {

        return $allow;

    }

    $order = wc_get_order( $order_id );

    if ( ! $order || ! is_a( $order, 'WC_Order' ) ) {

        return $allow;

    }

    $customer_id   = (int) $order->get_customer_id();

    $billing_email = $order->get_billing_email();

    $customer      = $customer_id > 0 ? $customer_id : $billing_email;

    if ( empty( $customer ) ) {

        return $allow;

    }

    // Fetch every order status registered on the site, including custom

    // statuses added by third-party plugins like WooCommerce Lottery.

    $all_statuses = array_map(

        function( $s ) { return str_replace( 'wc-', '', $s ); },

        array_keys( wc_get_order_statuses() )

    );

    // Check for any previous order from this customer, excluding the current one.

    $previous_orders = wc_get_orders( array(

        'customer' => $customer,

        'exclude'  => array( $order_id ),

        'status'   => $all_statuses,

        'limit'    => 1,

        'return'   => 'ids',

    ) );

    if ( ! empty( $previous_orders ) ) {

        return false; // Returning customer — block the referral.

    }

    return $allow;

}

add_filter( 'affwp_integration_create_referral', 'my_affwp_no_referral_for_existing_customers', 10, 2 );