Error handling

    // Swift errors are not converted to Swift yet.

    /// Due to a problem with the device internet connection it was not possible to initiate the requested action.
    ONGGenericErrorNetworkConnectivityFailure = 9000,
    /// Check the SDK configuration for the correct server URL.
    ONGGenericErrorServerNotReachable = 9001,
    /// The device registration was removed. All locally stored data is removed from the device and the user needs to register again.
    ONGGenericErrorDeviceDeregistered = 9002,
    /// The user account is deregistered from the device. The user supplied the wrong PIN for too many times. All local data associated with the user profile has been removed.
    ONGGenericErrorUserDeregistered = 9003,
    /// The Mobile Identity module denotes that the current app is no longer valid and can no longer be used. The end-user must update the application. Updating the SDK configuration might also solve the problem.
    ONGGenericErrorOutdatedApplication = 9004,
    /// The Mobile Identity module does not allow this application to run on the current OS version. Instruct the user to update the OS.
    ONGGenericErrorOutdatedOS = 9005,
    /// Requested action was cancelled.
    ONGGenericErrorActionCancelled = 9006,
    /// Another action already in progress and can not be performed concurrently.
    ONGGenericErrorActionAlreadyInProgress = 9007,
    /// An unknown error occurred
    ONGGenericErrorUnknown = 10000,
    /// The IDAAS-core configuration is invalid.
    ONGGenericErrorConfigurationInvalid = 10001,
    /// The request to the IDAAS-core was invalid. Please verify that the IDAAS-core configuration is correct and that no reverse proxy is interfering with the connection.
    ONGGenericErrorRequestInvalid = 10015,
    /// The device could not be registered with the IDAAS-core, verify that the SDK configuration, IDAAS-core configuration, and security features are correctly configured.
    ONGGenericErrorDeviceRegistrationFailure = 9008,
    /// The data storage could not be accessed.
    ONGGenericErrorDataStorageNotAvailable = 9024,
    /// The data storage is corrupted and cannot be recovered or cleared.
    ONGGenericErrorUnrecoverableDataState = 9025
    /// Application integrity check failed. Please verify application signature on the IDAAS-core.
    ONGGenericErrorAppIntegrityFailure = 10024,

    func userClient(_ userClient: UserClient, 
                    didFailToRegisterWith identityProvider: IdentityProvider, 
                    error: Error) {
    // Errors are going to be within ONGGenericErrorDomain or ONGRegistrationErrorDomain domains.
        switch error.code {
            // Both errors from ONGRegistrationErrorDomain mean that registration can not be completed.
            // Most likely you will encounter them only during development with invalid configuration.

            // The device could not be registered with the IDAAS-core, verify that the SDK configuration, IDAAS-core configuration and security features are correctly configured
            case ONGRegistrationError.deviceRegistrationFailure.rawValue:
                // A possible security issue was detected during User Registration.
            case ONGRegistrationError.invalidState.rawValue:
                // display an error to the user, hide registration UI, etc

                // Generic errors
                // In case the user has cancelled the PIN challenge, the cancellation error will be reported. This error can be ignored.
            case ONGGenericError.actionCancelled.rawValue:

                // Undefined error occurred
            case ONGGenericError.unknown.rawValue:

                // Typical network errors
            case ONGGenericError.networkConnectivityFailure.rawValue:
            case ONGGenericError.serverNotReachable.rawValue:

                // This error should not happen in the Production because it means that the configuration is invalid and / or server has proxy.
                // Developer will most likely face with such errors during development itself.
            case ONGGenericError.requestInvalid.rawValue:

                // The user trying to perform registration, but previous registration is not finished yet.
            case ONGGenericError.actionAlreadyInProgress.rawValue:

                // You typical won't face the ONGGenericErrorOutdatedApplication and ONGGenericErrorOutdatedOS during PIN change.
                // However it is potentially possible, so we need to handle them as well.
            case ONGGenericError.outdatedApplication.rawValue:
            case ONGGenericError.outdatedOS.rawValue:

            default:
                // display error.
        }

        show(error)
        completion()
    }

    - (void)userClient:(ONGUserClient *)userClient didFailToRegisterWithError:(NSError *)error identityProvider:(ONGIdentityProvider *)identityProvider
    {
        // Errors are going to be within ONGGenericErrorDomain or ONGRegistrationErrorDomain domains.
        switch (error.code) {
            // Both errors from ONGRegistrationErrorDomain mean that registration can not be completed.
            // Most likely you will encounter them only during development with invalid configuration.

            // The device could not be registered with the IDAAS-core, verify that the SDK configuration, IDAAS-core and security features are correctly configured
            case ONGRegistrationErrorDeviceRegistrationFailure:
                // A possible security issue was detected during User Registration.
            case ONGRegistrationErrorInvalidState:
                // display an error to the user, hide registration UI, etc
                break;

                // Generic errors
                // In case the user has cancelled the PIN challenge, the cancellation error will be reported. This error can be ignored.
            case ONGGenericErrorActionCancelled:
                break;

                // Undefined error occurred
            case ONGGenericErrorUnknown:

                // Typical network errors
            case ONGGenericErrorNetworkConnectivityFailure:
            case ONGGenericErrorServerNotReachable:

                // This error should not happen in the Production because it means that the configuration is invalid and / or server has proxy.
                // Developer will most likely face with such errors during development itself.
            case ONGGenericErrorRequestInvalid:

                // The user trying to perform registration, but previous registration is not finished yet.
            case ONGGenericErrorActionAlreadyInProgress:

                // You typical won't face the ONGGenericErrorOutdatedApplication and ONGGenericErrorOutdatedOS during PIN change.
                // However it is potentially possible, so we need to handle them as well.
            case ONGGenericErrorOutdatedApplication:
            case ONGGenericErrorOutdatedOS:

            default:
                // display error.
                break;
        }

        [self showError:error];

        self.completion();
    }

    - (void)showError:(NSError *)error
    {
        [self.navigationController popToRootViewControllerAnimated:YES];
        UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Registration Error"
                                                                    message:error.localizedDescription
                                                                preferredStyle:UIAlertControllerStyleAlert];
        UIAlertAction *okButton = [UIAlertAction actionWithTitle:@"Ok"
                                                        style:UIAlertActionStyleDefault
                                                        handler:nil];
        [alert addAction:okButton];
        [self.navigationController presentViewController:alert animated:YES completion:nil];
    }