Add MFA view controller and support MFA

FirebaseAuth/Tests/SampleSwift/AuthenticationExample.xcodeproj/project.pbxproj

@@ -50,6 +50,7 @@
 		EA527CAC24A0EE9600ADB9A2 /* LoginView.swift in Sources */ = {isa = PBXBuildFile; fileRef = EA527CAB24A0EE9600ADB9A2 /* LoginView.swift */; };
 		EAB3A1792494433500385291 /* DataSourceProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = EAB3A1782494433500385291 /* DataSourceProvider.swift */; };
 		EAB3A17C2494628200385291 /* UserViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = EAB3A17B2494628200385291 /* UserViewController.swift */; };
+		EAD8BD402CE535C400E23E30 /* MFALoginView.swift in Sources */ = {isa = PBXBuildFile; fileRef = EAD8BD3F2CE535C400E23E30 /* MFALoginView.swift */; };
 		EAE08EB524CF5D09006FA3A5 /* AccountLinkingViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = EAE08EB424CF5D09006FA3A5 /* AccountLinkingViewController.swift */; };
 		EAE4CBC524855E3A00245E92 /* AppDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = EAE4CBC424855E3A00245E92 /* AppDelegate.swift */; };
 		EAE4CBC724855E3A00245E92 /* SceneDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = EAE4CBC624855E3A00245E92 /* SceneDelegate.swift */; };
@@ -128,6 +129,7 @@
 		EA527CAB24A0EE9600ADB9A2 /* LoginView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LoginView.swift; sourceTree = "<group>"; };
 		EAB3A1782494433500385291 /* DataSourceProvider.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DataSourceProvider.swift; sourceTree = "<group>"; };
 		EAB3A17B2494628200385291 /* UserViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UserViewController.swift; sourceTree = "<group>"; };
+		EAD8BD3F2CE535C400E23E30 /* MFALoginView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MFALoginView.swift; sourceTree = "<group>"; };
 		EAE08EB424CF5D09006FA3A5 /* AccountLinkingViewController.swift */ = {isa = PBXFileReference; indentWidth = 2; lastKnownFileType = sourcecode.swift; path = AccountLinkingViewController.swift; sourceTree = "<group>"; };
 		EAE4CBC124855E3A00245E92 /* AuthenticationExample.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = AuthenticationExample.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		EAE4CBC424855E3A00245E92 /* AppDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppDelegate.swift; sourceTree = "<group>"; };
@@ -244,6 +246,7 @@
 		EA20B47724973BB100B5E581 /* CustomViews */ = {
 			isa = PBXGroup;
 			children = (
+				EAD8BD3F2CE535C400E23E30 /* MFALoginView.swift */,
 				EA20B46B2495A9F900B5E581 /* SignedOutView.swift */,
 				EA527CAB24A0EE9600ADB9A2 /* LoginView.swift */,
 			);
@@ -561,6 +564,7 @@
 				EA20B510249FDB4400B5E581 /* OtherAuthMethods.swift in Sources */,
 				EA12697F29E33A5D00D79E66 /* CryptoUtils.swift in Sources */,
 				EAEBCE11248A9AA000FCEA92 /* Section.swift in Sources */,
+				EAD8BD402CE535C400E23E30 /* MFALoginView.swift in Sources */,
 				DEC2E5DF2A9583CA0090260A /* AppManager.swift in Sources */,
 				DEC2E5DD2A95331E0090260A /* SettingsViewController.swift in Sources */,
 				EA20B503249C6C3D00B5E581 /* CustomAuthViewController.swift in Sources */,
@@ -789,7 +793,7 @@
 				CODE_SIGN_STYLE = Manual;
 				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = AuthenticationExample/SwiftApplication.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 13.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.6;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -812,7 +816,7 @@
 				CODE_SIGN_STYLE = Manual;
 				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = AuthenticationExample/SwiftApplication.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 13.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.6;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",

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

@@ -0,0 +1,189 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import FirebaseAuth
+import SwiftUI
+
+struct MFALoginView: View {
+  @Environment(\.dismiss) private var dismiss
+
+  @State private var factorSelection: MultiFactorInfo?
+  // This is only needed for phone MFA.
+  @State private var verificationId: String?
+  // This is needed for both phone and TOTP MFA.
+  @State private var verificationCode: String = ""
+
+  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.")
+      .padding(.top)
+    List(resolver.hints, id: \.self, selection: $factorSelection) {
+      Text($0.displayName ?? "No display name provided.")
+    }
+    .frame(height: 300)
+    .clipShape(RoundedRectangle(cornerRadius: 15))
+    .padding()
+
+    if let factorSelection {
+      // TODO(ncooke3): This logic handles both phone and TOTP MFA states. Investigate how to make
+      // more clear with better APIs.
+      if factorSelection.factorID == PhoneMultiFactorID, verificationId == nil {
+        MFAViewButton(
+          text: "Send Verification Code",
+          accentColor: .white,
+          backgroundColor: .orange
+        ) {
+          Task { await startMfALogin() }
+        }
+        .padding()
+      } else {
+        TextField("Enter verification code.", text: $verificationCode)
+          .textFieldStyle(SymbolTextField(symbolName: "lock.circle.fill"))
+          .padding()
+        MFAViewButton(
+          text: "Sign in",
+          accentColor: .white,
+          backgroundColor: .orange
+        ) {
+          Task { await finishMfALogin() }
+        }
+        .padding()
+      }
+    }
+    Spacer()
+  }
+}
+
+extension MFALoginView {
+  private func startMfALogin() async {
+    guard let factorSelection else { return }
+    switch factorSelection.factorID {
+    case PhoneMultiFactorID:
+      await startPhoneMultiFactorSignIn(hint: factorSelection as? PhoneMultiFactorInfo)
+    case TOTPMultiFactorID: break // TODO(ncooke3): Indicate to user to get verification code.
+    default: return
+    }
+  }
+
+  private func startPhoneMultiFactorSignIn(hint: PhoneMultiFactorInfo?) async {
+    guard let hint else { return }
+    do {
+      verificationId = try await PhoneAuthProvider.provider().verifyPhoneNumber(
+        with: hint,
+        uiDelegate: nil,
+        multiFactorSession: resolver.session
+      )
+    } catch {
+      print(error)
+    }
+  }
+
+  private func finishMfALogin() async {
+    guard let factorSelection else { return }
+    switch factorSelection.factorID {
+    case PhoneMultiFactorID:
+      await finishPhoneMultiFactorSignIn()
+    case TOTPMultiFactorID:
+      await finishTOTPMultiFactorSignIn(hint: factorSelection)
+    default: return
+    }
+  }
+
+  private func finishPhoneMultiFactorSignIn() async {
+    guard let verificationId else { return }
+    let credential = PhoneAuthProvider.provider().credential(
+      withVerificationID: verificationId,
+      verificationCode: verificationCode
+    )
+    let assertion = PhoneMultiFactorGenerator.assertion(with: credential)
+    do {
+      _ = try await resolver.resolveSignIn(with: assertion)
+      // MFA login was successful.
+      await MainActor.run {
+        dismiss()
+        delegate?.loginDidOccur(resolver: nil)
+      }
+    } catch {
+      print(error)
+    }
+  }
+
+  private func finishTOTPMultiFactorSignIn(hint: MultiFactorInfo) async {
+    // TODO(ncooke3): Disable button if verification code textfield contents is empty.
+    guard verificationCode.count > 0 else { return }
+    let assertion = TOTPMultiFactorGenerator.assertionForSignIn(
+      withEnrollmentID: hint.uid,
+      oneTimePassword: verificationCode
+    )
+    do {
+      _ = try await resolver.resolveSignIn(with: assertion)
+      // MFA login was successful.
+      await MainActor.run {
+        dismiss()
+        delegate?.loginDidOccur(resolver: nil)
+      }
+    } catch {
+      // Wrong or expired OTP. Re-prompt the user.
+      // TODO(ncooke3): Show error to user.
+      print(error)
+    }
+  }
+}
+
+private struct MFAViewButton: View {
+  let text: String
+  let accentColor: Color
+  let backgroundColor: Color
+  let action: () -> Void
+
+  var body: some View {
+    Button(action: action) {
+      HStack {
+        Spacer()
+        Text(text)
+          .bold()
+          .accentColor(accentColor)
+        Spacer()
+      }
+      .padding()
+      .background(backgroundColor)
+      .cornerRadius(14)
+    }
+  }
+}
+
+private struct SymbolTextField: TextFieldStyle {
+  let symbolName: String
+
+  func _body(configuration: TextField<Self._Label>) -> some View {
+    HStack {
+      Image(systemName: symbolName)
+        .foregroundColor(.orange)
+        .imageScale(.large)
+        .padding(.leading)
+      configuration
+        .padding([.vertical, .trailing])
+    }
+    .background(Color(uiColor: .secondarySystemBackground))
+    .cornerRadius(14)
+    .textInputAutocapitalization(.never)
+  }
+}

FirebaseAuth/Tests/SampleSwift/AuthenticationExample/Models/OtherAuthMethods.swift

@@ -19,6 +19,7 @@ enum OtherAuthMethod: String {
   case Passwordless = "Email Link/Passwordless"
   case PhoneNumber = "Phone Auth"
   case Custom = "a Custom Auth System"
+  case MfaLogin = "Multifactor Authentication"
 
   var navigationTitle: String { "Sign in using \(rawValue)" }
 
@@ -30,6 +31,8 @@ enum OtherAuthMethod: String {
       return "Enter Phone Number"
     case .Custom:
       return "Enter Custom Auth Token"
+    case .MfaLogin:
+      return "Choose a Second Factor to Continue"
     }
   }
 
@@ -41,13 +44,17 @@ enum OtherAuthMethod: String {
       return "phone.circle"
     case .Custom:
       return "lock.shield"
+    case .MfaLogin:
+      return "phone.circle"
     }
   }
 
   var textFieldInputText: String? {
     switch self {
     case .PhoneNumber:
       return "Example input for +1 (123)456-7890 would be 11234567890"
+    case .MfaLogin:
+      return "Enter the index of the selected factor to continue"
     default:
       return nil
     }
@@ -61,6 +68,8 @@ enum OtherAuthMethod: String {
       return "Send Verification Code"
     case .Custom:
       return "Login"
+    case .MfaLogin:
+      return "Send Verification Code"
     }
   }
 
@@ -72,9 +81,17 @@ enum OtherAuthMethod: String {
       return phoneNumberInfoText
     case .Custom:
       return customAuthInfoText
+    case .MfaLogin:
+      return mfaLoginInfoText
     }
   }
 
+  private var mfaLoginInfoText: String {
+    """
+    MFA placeholder
+    """
+  }
+
   private var passwordlessInfoText: String {
     """
     Authenticate users with only their email, \

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?)
 }