[Auth] Extend MFA login flow to email/password page

FirebaseAuth/Tests/SampleSwift/AuthenticationExample/CustomViews/MFALoginView.swift

@@ -24,7 +24,13 @@ struct MFALoginView: View {
   // This is needed for both phone and TOTP MFA.
   @State private var verificationCode: String = ""
 
-  let resolver: MultiFactorResolver
+  private let resolver: MultiFactorResolver
+  private weak var delegate: (any LoginDelegate)?
+
+  init(resolver: MultiFactorResolver, delegate: (any LoginDelegate)?) {
+    self.resolver = resolver
+    self.delegate = delegate
+  }
 
   var body: some View {
     Text("Choose a second factor to continue.")
@@ -113,6 +119,7 @@ extension MFALoginView {
       // MFA login was successful.
       await MainActor.run {
         dismiss()
+        delegate?.loginDidOccur(resolver: nil)
       }
     } catch {
       print(error)
@@ -131,6 +138,7 @@ extension MFALoginView {
       // MFA login was successful.
       await MainActor.run {
         dismiss()
+        delegate?.loginDidOccur(resolver: nil)
       }
     } catch {
       // Wrong or expired OTP. Re-prompt the user.

FirebaseAuth/Tests/SampleSwift/AuthenticationExample/Utility/LoginDelegate.swift

@@ -12,9 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+import FirebaseAuth
 import Foundation
 
 /// Delegate for signaling that a successful login with Firebase Auth has occurred
 protocol LoginDelegate: NSObject {
-  func loginDidOccur()
+  func loginDidOccur(resolver: MultiFactorResolver?)
 }

FirebaseAuth/Tests/SampleSwift/AuthenticationExample/ViewControllers/AuthViewController.swift

@@ -357,7 +357,10 @@
   }
 
   private func performMfaLoginFlow(resolver: MultiFactorResolver) {
-    let mfaLoginController = UIHostingController(rootView: MFALoginView(resolver: resolver))
+    let mfaLoginController = UIHostingController(rootView: MFALoginView(
+      resolver: resolver,
+      delegate: self
+    ))
     present(mfaLoginController, animated: true)
   }
 
@@ -1010,7 +1013,7 @@
     alertController.addAction(submitAction)
 
     // Present the alert controller
     UIApplication.shared.windows.first?.rootViewController?.present(
       alertController,
       animated: true,
       completion: nil
@@ -1067,8 +1070,12 @@
 // MARK: - LoginDelegate
 
 extension AuthViewController: LoginDelegate {
-  public func loginDidOccur() {
-    transitionToUserViewController()
+  public func loginDidOccur(resolver: MultiFactorResolver?) {
+    if let resolver {
+      performMfaLoginFlow(resolver: resolver)
+    } else {
+      transitionToUserViewController()
+    }
   }
 }
 

FirebaseAuth/Tests/SampleSwift/AuthenticationExample/ViewControllers/LoginController.swift

@@ -64,15 +64,25 @@ class LoginController: UIViewController {
 
   private func login(with email: String, password: String) {
     AppManager.shared.auth().signIn(withEmail: email, password: password) { result, error in
-      guard error == nil else { return self.displayError(error) }
-      self.delegate?.loginDidOccur()
+      if let error {
+        let authError = error as NSError
+        if authError.code == AuthErrorCode.secondFactorRequired.rawValue {
+          let resolver = authError
+            .userInfo[AuthErrorUserInfoMultiFactorResolverKey] as! MultiFactorResolver
+          self.delegate?.loginDidOccur(resolver: resolver)
+        } else {
+          self.displayError(error)
+        }
+      } else {
+        self.delegate?.loginDidOccur(resolver: nil)
+      }
     }
   }
 
   private func createUser(email: String, password: String) {
     AppManager.shared.auth().createUser(withEmail: email, password: password) { authResult, error in
       guard error == nil else { return self.displayError(error) }
-      self.delegate?.loginDidOccur()
+      self.delegate?.loginDidOccur(resolver: nil)
     }
   }
 

FirebaseAuth/Tests/SampleSwift/AuthenticationExample/ViewControllers/OtherAuthMethodControllers/CustomAuthViewController.swift

@@ -32,7 +32,7 @@ class CustomAuthViewController: OtherAuthViewController {
     AppManager.shared.auth().signIn(withCustomToken: token) { result, error in
       guard error == nil else { return self.displayError(error) }
       self.navigationController?.dismiss(animated: true, completion: {
-        self.delegate?.loginDidOccur()
+        self.delegate?.loginDidOccur(resolver: nil)
       })
     }
   }

FirebaseAuth/Tests/SampleSwift/AuthenticationExample/ViewControllers/OtherAuthMethodControllers/PasswordlessViewController.swift

@@ -67,7 +67,7 @@ class PasswordlessViewController: OtherAuthViewController {
         print("User verified with passwordless email.")
 
         self.navigationController?.dismiss(animated: true) {
-          self.delegate?.loginDidOccur()
+          self.delegate?.loginDidOccur(resolver: nil)
         }
       } else {
         print("User could not be verified by passwordless email")

FirebaseAuth/Tests/SampleSwift/AuthenticationExample/ViewControllers/OtherAuthMethodControllers/PhoneAuthViewController.swift

@@ -47,7 +47,7 @@ class PhoneAuthViewController: OtherAuthViewController {
     AppManager.shared.auth().signIn(with: credential) { result, error in
       guard error == nil else { return self.displayError(error) }
       self.navigationController?.dismiss(animated: true, completion: {
-        self.delegate?.loginDidOccur()
+        self.delegate?.loginDidOccur(resolver: nil)
       })
     }
   }