Augmenting the Login method with calls to the MFA provider

AccountController.cs

       //
        // POST: /Account/Login
        [HttpPost]
        [AllowAnonymous]
        [ValidateAntiForgeryToken]
        public async Task<ActionResult> Login(LoginViewModel model, string returnUrl)
        {
            if (ModelState.IsValid)
            {
                var user = await UserManager.FindAsync(model.Email, model.Password);
                if (user != null)
                {
                    await SignInAsync(user, model.RememberMe);
                    
                    // Variables to store MFA results
                    string otp = "";
                    int callStatus = 0;
                    int errorId = 0;

                    // Prepare the MFA Parameters
                    PfAuthParams pfAuthParams = new PfAuthParams();
                    pfAuthParams.CountryCode = user.CountryCode;
                    pfAuthParams.Phone = user.Phone;
                    pfAuthParams.Pin = user.PIN.ToString();

                    // Load the certificate
                    pfAuthParams.CertFilePath = System.Web.HttpContext.Current.Server.MapPath("~/pf/certs/cert_key.p12");
                    
                    // Choose one of the below methods for authentication
                    pfAuthParams.Mode = pf_auth.MODE_STANDARD; // a phone call without a pin
                    //pfAuthParams.Mode = pf_auth.MODE_PIN; // pin
                    //pfAuthParams.Mode = pf_auth.MODE_VOICEPRINT; // voice print
                    //pfAuthParams.Mode = pf_auth.MODE_SMS_TWO_WAY_OTP; // sms him a one time password that he has to send back
                    //pfAuthParams.Mode = pf_auth.MODE_SMS_TWO_WAY_OTP_PLUS_PIN; // sms him a one time password that he has to send back + pin

                    // If using SMS, set the below according to the SMS mode
                    //pfAuthParams.SmsText = "<$otp$>\nReply with this one-time passcode to complete your authentication.";
                    //pfAuthParams.SmsText = "<$otp$>\nReply with this one-time passcode and your PIN to complete your authentication.";

                    // Call the MFA Provider
                    // the return value from the function is a boolean that is the result of
                    // the authentication.  Two out arguments are also returned.  The first is the
                    // result of the phonecall itself, the second is the result of the connection
                    // with the backend.  See call_results.txt for a list of call results
                    // and descriptions that correspond to value returned.
                    bool mfaResult = pf_auth.pf_authenticate(pfAuthParams, out otp, out callStatus, out errorId);

                    // If MFA succeeded
                    if (mfaResult == true)
                        return RedirectToLocal(returnUrl);
                    else
                        ModelState.AddModelError("", "Multi-factor Authentication failed.");
                }
                else
                {
                    ModelState.AddModelError("", "Invalid username or password.");
                }
            }

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