[Auth] Add general MFA sign-in sheet

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 +1,178 @@
+// 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 = ""
+
+  let resolver: MultiFactorResolver
+
+  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
+        ) {
+          // TODO(ncooke3): Does this task inherit a higher priority? What about the regular SwiftUI
+          // button?
+          Task(priority: .userInitiated, operation: 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(priority: .userInitiated, operation: 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)
+      dismiss()
+    } 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.
+      dismiss()
+    } 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/ViewControllers/AuthViewController.swift

@@ -27,6 +27,8 @@ import GameKit
 import GoogleSignIn
 import UIKit
 
+import SwiftUI
+
 // For Sign in with Apple
 import AuthenticationServices
 import CryptoKit
@@ -355,10 +357,8 @@ class AuthViewController: UIViewController, DataSourceProviderDelegate {
   }
 
   private func performMfaLoginFlow(resolver: MultiFactorResolver) {
-    let mfaLoginController = MFALoginViewController(resolver: resolver)
-    mfaLoginController.delegate = self
-    let navMfaLoginController = UINavigationController(rootViewController: mfaLoginController)
-    navigationController?.present(navMfaLoginController, animated: true)
+    let mfaLoginController = UIHostingController(rootView: MFALoginView(resolver: resolver))
+    present(mfaLoginController, animated: true)
   }
 
   private func performAnonymousLoginFlow() {