public async Task OnPostAsync()

in Source/WebApp-IdentityProvider-MFA/Areas/Identity/Pages/Account/Register.cshtml.cs [112:166]
48 lines of code
5 McCabe index (conditional complexity)

        public async Task<IActionResult> OnPostAsync(string returnUrl = null)
        {
            returnUrl ??= Url.Content("~/Identity/Account/Manage");
            if (ModelState.IsValid)
            {
                var user = new ApplicationUser//TODO
                {
                    GivenName = Input.GivenName,
                    FamilyName = Input.FamilyName,
                    BirthDate = Input.BirthDate,
                    BirthCountry = Input.BirthCountry,
                    BirthPlace= Input.BirthPlace,
                    Gender = Input.Gender,
                    PreferredName = Input.PreferredName
                };

                await _userStore.SetUserNameAsync(user, Input.Email, CancellationToken.None);
                await _emailStore.SetEmailAsync(user, Input.Email, CancellationToken.None);
                var result = await _userManager.CreateAsync(user, Input.Password);

                if (result.Succeeded)
                {
                    _logger.LogInformation("User created a new account with password.");

                    var userId = await _userManager.GetUserIdAsync(user);
                    var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
                    code = WebEncoders.Base64UrlEncode(Encoding.UTF8.GetBytes(code));
                    var callbackUrl = Url.Page(
                        "/Account/ConfirmEmail",
                        pageHandler: null,
                        values: new { area = "Identity", userId, code, returnUrl },
                        protocol: Request.Scheme);

                    await _emailSender.SendEmailAsync(Input.Email, "Confirmez votre adresse mail",
                        $"Veuillez confirmer votre compte en <a href='{HtmlEncoder.Default.Encode(callbackUrl)}'>cliquant ici</a>.");

                    if (_userManager.Options.SignIn.RequireConfirmedAccount)
                    {
                        return RedirectToPage("RegisterConfirmation", new { email = Input.Email, returnUrl });
                    }
                    else
                    {
                        await _signInManager.SignInAsync(user, isPersistent: false);
                        return LocalRedirect(returnUrl);
                    }
                }
                foreach (var error in result.Errors)
                {
                    ModelState.AddModelError(string.Empty, error.Description);
                }
            }

            // If we got this far, something failed, redisplay form
            return Page();
        }