adapt Gravity Forms notification rules based on country in an Address field

gf-email-route-by-country.php

<?php

if (!defined('ABSPATH')) {
    exit;
}

/**
 * adapt notification rules based on country in Address field
 * - set Send To email address to a trigger value
 * - set Value to the address field ID
 * - doesn't matter what the other values are
 * @param array $notification
 * @param array $form
 * @param array $entry
 */
add_filter('gform_notification', function($notification, $form, $entry) {
    // only if using email routing
    if (rgar($notification, 'toType') === 'routing' && !empty($notification['routing'])) {
        // check for trigger value, otherwise it's using regular email routing
        $route = $notification['routing'][0];
        if (rgar($route, 'email') === 'trigger@example.com') {
            $field = GFAPI::get_field($form['id'], rgar($route, 'value'));
            if ($field instanceof GF_Field && $field->type === 'address') {
                $map = [
                    'Australia'         => 'au@example.com',
                    'United States'     => 'us@example.com',
                    'China'             => 'cn@example.com',
                    'Brazil'            => 'br@example.com',
                ];

                // get Country value and use it to determine email address, with a fallback address
                $value = rgar($entry, $field->id . '.6');
                $email = $map[$value] ?? 'general@example.com';

                $notification['toType']   = 'email';
                $notification['toEmail']  = $email;
                $notification['to']       = $email;
                $notification['routing']  = [];
            }
        }
    }
    return $notification;
}, 10, 3);