public async Task <IActionResult> PostUser(RegisterUserRequestModel requestModel)
        {
            if (requestModel?.DeviceInfo == null ||
                string.IsNullOrWhiteSpace(requestModel.DeviceInfo.Handle) ||
                InvalidPlatForm(requestModel.DeviceInfo.Platform) ||
                string.IsNullOrWhiteSpace(requestModel.UserInfo?.UserName))
            {
                return(BadRequest());
            }

            var email = User.Claims.FirstOrDefault(c => c.Type == ClaimTypes.Email)?.Value;

            var user = await _userAuthenticationService.Add3rdPartyUser(requestModel.UserInfo.UserName, email);

            if (user?.User == null)
            {
                return(BadRequest("User could not be created. The username is invalid or is already be in use."));
            }

            var update = requestModel.Registration?.RegistrationId == null
                ? null
                : await _hubRegistrationService.UpdateHubRegistration(new UpdateRegistrationRequestModel
            {
                Handle         = requestModel.DeviceInfo.Handle,
                Platform       = requestModel.DeviceInfo.Platform,
                RegistrationId = requestModel.Registration.RegistrationId,
                Username       = requestModel.UserInfo.UserName
            });

            HubRegistrationModel reg;

            if (update == null)
            {
                //todo: need to pass tags
                reg = await _hubRegistrationService.CreateHubRegistration(requestModel.DeviceInfo.Handle);
            }
            else
            {
                reg = new HubRegistrationModel
                {
                    RegistrationId = update.RegistrationId
                };
            }

            var clientAuthConfigModel = GetClientAuthConfigModel();

            return(Ok(new StartupResponseModel
            {
                ClientAuth = clientAuthConfigModel,
                HubRegistration = reg,
                Authentication = new AuthenticationModel
                {
                    Token = string.Empty
                },
            }));
        }