require __DIR__ . '/vendor/autoload.php';

// Setup NotificationReceiver with dependency injection or create an instance as follows
$notificationReceiver = new \Adyen\Webhook\Receiver\NotificationReceiver(new \Adyen\Webhook\Receiver\HmacSignature);
// Authorize notification
if (!$notificationReceiver->isAuthenticated(
    $request['notificationItems'][0]['NotificationRequestItem'],
    YOUR_MERCHANT_ACCOUNT,
    YOUR_NOTIFICATION_USERNAME,
    YOUR_NOTIFICATION_PASSWORD
)) {
    throw new AuthenticationException();
}
// Process each notification item
foreach ($request['notificationItems'] as $notificationItem) {
    // validate the notification
    if ($notificationReceiver->validateHmac($notificationItem, YOUR_HMAC_KEY)) {
       // save notification to your database
       $this->databaseService->saveNotification($notificationItem); 
    }
}
return new JsonResponse('[accepted]');

$notificationItem = \Adyen\Webhook\Notification::createItem([
    'eventCode' => $notification['eventCode'],
    'success' => $notification['success']
]);
$processor = \Adyen\Webhook\Processor\ProcessorFactory::create(
    $notificationItem,
    $currentPaymentState,
    $this->logger
);
$newState = $processor->process();