/**
 * @param bool $result  Whether the notification conditions have passed
 * @param \GeminiLabs\SiteReviews\Addon\Notifications\Notification $notification  The Notification object
 *
 * @return bool - true if the notification should be sent, false otherwise.
 */
add_filter('site-reviews-notifications/notification/is-valid', function ($result, $notification) {
    $uid = 'abcdef'; // Replace with the UID of the notification.
    if (!$result || $uid !== $notification->get('uid')) {
        return $result; // Conditions have already failed or wrong notification
    }
    $user = wp_get_current_user();
    if (!in_array('retail', $user->roles)) {
        return false; // Skip if user does not have the retail role
    }
    if (wc_get_customer_order_count($user->ID) > 1) {
        return true; // Skip if not the first order
    }
    if (!empty(get_user_meta($user->ID, '_coupon_email_sent', true))) {
        return false; // Skip if user has already been sent a coupon
    }
    update_user_meta($user->ID, '_coupon_email_sent', 1);
    return true; // Send notification
}, 10, 2);