public function onCallbackSuccess($order, $data = null)
    {
        $paymentId  = is_array($data) ? $data['paymentId'] : $data->paymentId;

        $payerId    = is_array($data) ? $data['PayerID'] : $data->PayerID;

        $this->statusCode = 'failed';

        $this->detail = sprintf('Payment failed. Ref: %s', $paymentId);

        // Begin paypal
        try {

            $this->setContext();

            $payment = Payment::get($paymentId, $this->apiContext);
            
            $execution = new PaymentExecution();

            $execution->setPayerId($payerId);

            $payment->execute($execution, $this->apiContext);

            $payment = Payment::get($paymentId, $this->apiContext);

            $this->statusCode = 'completed';

            $this->transactionId = $payment->id;

            $this->detail = 'Success';

        } catch (PayPalConnectionException $e) {

            $response = json_decode($e->getData());

            throw new GatewayException(
                sprintf(
                    '%s: %s',
                    $response->name,
                    isset($response->message) ? $response->message : 'Paypal payment Failed.'
                ),
                1001,
                $e
            );

        } catch (\Exception $e) {

            throw new GatewayException(
                $e->getMessage(),
                1000,
                $e
            );

        }
    }