public function saveSubscription(int $userId = null) : void
    {
        $json = \file_get_contents('php://input');

        if (!$json)
        {
            return;
        }

        $data = \json_decode($json, true);

        if (!$data || empty($data['endpoint']) || empty($data['publicKey']) || empty($data['authToken']))
        {
            return;
        }

        $row = $this->subscriptionTable->findActive()->where('endpoint', $data['endpoint'])->fetch();

        switch ($this->request->getMethod()) {
            case 'POST':
            case 'PUT':
            {
                if ($row)
                {
                    $row->update([
                        'user_id' => $userId ?: $row->user_id ?: null,
                        'key' => $data['publicKey'],
                        'token' => $data['authToken'],
                        'encoding' => $data['contentEncoding']
                    ]);
                    
                    return;
                }

                $row = $this->subscriptionTable->insert([
                    'user_id' => $userId,
                    'endpoint' => $data['endpoint'],
                    'key' => $data['publicKey'],
                    'token' => $data['authToken'],
                    'encoding' => $data['contentEncoding']
                ]);

                $this->sendNotification($row, 'Notifications enabled!', true);

                return;
            }
            case 'DELETE':
            {
                if ($row)
                {
                    $row->update([
                        'active' => 0
                    ]);
                }

                return;
            }
            default:
                throw new \Nette\Application\BadRequestException();
        }
    }