refactor: made changes to API to reduce AuthService API surface area

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Auth/MultiFactor.swift

@@ -100,12 +100,12 @@ public struct EnrollmentSession {
   }
 }
 
-public enum MFAHint {
+public enum MFAHint: Hashable {
   case phone(displayName: String?, uid: String, phoneNumber: String?)
   case totp(displayName: String?, uid: String)
 }
 
-public struct MFARequired {
+public struct MFARequired: Hashable {
   public let hints: [MFAHint]
 
   public init(hints: [MFAHint]) {

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Services/AccountService+Email.swift

@@ -18,22 +18,24 @@ import Observation
 @MainActor
 @Observable
 public final class PasswordPromptCoordinator {
-  var isPromptingPassword = false
+  public var isPromptingPassword = false
   private var continuation: CheckedContinuation<String, Error>?
 
-  func confirmPassword() async throws -> String {
+  public init() {}
+
+  public func confirmPassword() async throws -> String {
     return try await withCheckedThrowingContinuation { continuation in
       self.continuation = continuation
       self.isPromptingPassword = true
     }
   }
 
-  func submit(password: String) {
+  public func submit(password: String) {
     continuation?.resume(returning: password)
     cleanup()
   }
 
-  func cancel() {
+  public func cancel() {
     continuation?
       .resume(throwing: AuthServiceError
         .signInCancelled("Password entry cancelled for Email provider"))

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Services/AuthService.swift

@@ -49,7 +49,7 @@ public enum AuthView: Hashable {
   case updatePassword
   case mfaEnrollment
   case mfaManagement
-  case mfaResolution
+  case mfaResolution(MFARequired)
   case enterPhoneNumber
   case enterVerificationCode(verificationID: String, fullPhoneNumber: String)
 }
@@ -132,14 +132,18 @@ public final class AuthService {
   public var authenticationState: AuthenticationState = .unauthenticated
   public var authenticationFlow: AuthenticationFlow = .signIn
 
-  public let passwordPrompt: PasswordPromptCoordinator = .init()
-  public var currentMFARequired: MFARequired?
   private var currentMFAResolver: MultiFactorResolver?
 
   // MARK: - Provider APIs
 
   private var listenerManager: AuthListenerManager?
 
+  private var emailProvider: EmailProviderSwift?
+
+  public var passwordPrompt: PasswordPromptCoordinator {
+    emailProvider?.passwordPrompt ?? PasswordPromptCoordinator()
+  }
+
   var emailSignInEnabled = false
   private var emailSignInCallback: (() -> Void)?
 
@@ -199,7 +203,7 @@ public final class AuthService {
         : .authenticated
   }
 
-  public var shouldHandleAnonymousUpgrade: Bool {
+  private var shouldHandleAnonymousUpgrade: Bool {
     currentUser?.isAnonymous == true && configuration.shouldAutoUpgradeAnonymousUsers
   }
 
@@ -317,14 +321,16 @@ public extension AuthService {
 
 public extension AuthService {
   /// Enable email sign-in with default behavior (navigates to email link view)
-  func withEmailSignIn() -> AuthService {
-    return withEmailSignIn { [weak self] in
+  func withEmailSignIn(_ provider: EmailProviderSwift? = nil) -> AuthService {
+    return withEmailSignIn(provider) { [weak self] in
       self?.navigator.push(.emailLink)
     }
   }
 
   /// Enable email sign-in with custom callback
-  func withEmailSignIn(onTap: @escaping () -> Void) -> AuthService {
+  func withEmailSignIn(_ provider: EmailProviderSwift? = nil,
+                       onTap: @escaping () -> Void) -> AuthService {
+    emailProvider = provider ?? EmailProviderSwift()
     emailSignInEnabled = true
     emailSignInCallback = onTap
     return self
@@ -747,8 +753,14 @@ public extension AuthService {
       guard let email = user.email else {
         throw AuthServiceError.invalidCredentials("User does not have an email address")
       }
-      let password = try await passwordPrompt.confirmPassword()
-      let credential = EmailAuthProvider.credential(withEmail: email, password: password)
+
+      guard let emailProvider = emailProvider else {
+        throw AuthServiceError.providerNotFound(
+          "Email provider not configured. Call withEmailSignIn() first."
+        )
+      }
+
+      let credential = try await emailProvider.createReauthCredential(email: email)
       _ = try await user.reauthenticate(with: credential)
     } else if providerId == PhoneAuthProviderID {
       // Phone auth requires manual reauthentication via sign out and sign in otherwise it will take
@@ -879,7 +891,6 @@ public extension AuthService {
 
   private func handleMFARequiredError(resolver: MultiFactorResolver) -> SignInOutcome {
     let hints = extractMFAHints(from: resolver)
-    currentMFARequired = MFARequired(hints: hints)
     currentMFAResolver = resolver
     return .mfaRequired(MFARequired(hints: hints))
   }
@@ -957,7 +968,6 @@ public extension AuthService {
       updateAuthenticationState()
 
       // Clear MFA resolution state
-      currentMFARequired = nil
       currentMFAResolver = nil
 
     } catch {

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Services/EmailProviderAuthUI.swift

@@ -0,0 +1,33 @@
+// Copyright 2025 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
+
+/// Email/Password authentication provider
+/// This provider is special and doesn't render in the button list
+@MainActor
+public class EmailProviderSwift: AuthProviderSwift {
+  public let passwordPrompt: PasswordPromptCoordinator
+  public let providerId = EmailAuthProviderID
+
+  public init(passwordPrompt: PasswordPromptCoordinator = .init()) {
+    self.passwordPrompt = passwordPrompt
+  }
+
+  /// Create credential for reauthentication
+  func createReauthCredential(email: String) async throws -> AuthCredential {
+    let password = try await passwordPrompt.confirmPassword()
+    return EmailAuthProvider.credential(withEmail: email, password: password)
+  }
+}

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Views/AuthPickerView.swift

@@ -33,10 +33,10 @@ public struct AuthPickerView<Content: View> {
 extension AuthPickerView: View {
   public var body: some View {
     @Bindable var authService = authService
-    @Bindable var passwordPrompt = authService.passwordPrompt
     content()
       .sheet(isPresented: $authService.isPresented) {
         @Bindable var navigator = authService.navigator
+        @Bindable var passwordPrompt = authService.passwordPrompt
         NavigationStack(path: $navigator.routes) {
           authPickerViewInternal
             .navigationTitle(authService.authenticationState == .unauthenticated ? authService
@@ -57,8 +57,8 @@ extension AuthPickerView: View {
                 MFAEnrolmentView()
               case AuthView.mfaManagement:
                 MFAManagementView()
-              case AuthView.mfaResolution:
-                MFAResolutionView()
+              case let .mfaResolution(mfaRequired):
+                MFAResolutionView(mfaRequired: mfaRequired)
               case AuthView.enterPhoneNumber:
                 EnterPhoneNumberView()
               case let .enterVerificationCode(verificationID, fullPhoneNumber):
@@ -79,10 +79,10 @@ extension AuthPickerView: View {
         .accountConflictHandler()
         // Apply MFA handling at NavigationStack level
         .mfaHandler()
-      }
-      // Centralized password prompt sheet to prevent conflicts
-      .sheet(isPresented: $passwordPrompt.isPromptingPassword) {
-        PasswordPromptSheet(coordinator: authService.passwordPrompt)
+        // Centralized password prompt sheet inside auth flow
+        .sheet(isPresented: $passwordPrompt.isPromptingPassword) {
+          PasswordPromptSheet(coordinator: passwordPrompt)
+        }
       }
   }
 

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Views/MFAHandlerModifier.swift

@@ -39,8 +39,8 @@ struct MFAHandlerModifier: ViewModifier {
   }
 
   /// Handle MFA required - navigate to MFA resolution view
-  func handleMFARequired(_: MFARequired) {
-    authService.navigator.push(.mfaResolution)
+  func handleMFARequired(_ mfaRequired: MFARequired) {
+    authService.navigator.push(.mfaResolution(mfaRequired))
   }
 }
 

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Views/MFAResolutionView.swift

@@ -23,6 +23,8 @@ private enum FocusableField: Hashable {
 
 @MainActor
 public struct MFAResolutionView {
+  let mfaRequired: MFARequired
+
   @Environment(AuthService.self) private var authService
   @Environment(\.reportError) private var reportError
 
@@ -34,16 +36,12 @@ public struct MFAResolutionView {
 
   @FocusState private var focus: FocusableField?
 
-  public init() {}
-
-  private var mfaRequired: MFARequired? {
-    // This would be set by the sign-in flow when MFA is required
-    authService.currentMFARequired
+  public init(mfaRequired: MFARequired) {
+    self.mfaRequired = mfaRequired
   }
 
   private var selectedHint: MFAHint? {
-    guard let mfaRequired = mfaRequired,
-          selectedHintIndex < mfaRequired.hints.count else {
+    guard selectedHintIndex < mfaRequired.hints.count else {
       return nil
     }
     return mfaRequired.hints[selectedHintIndex]
@@ -63,7 +61,7 @@ public struct MFAResolutionView {
   }
 
   private func startSMSChallenge() {
-    guard selectedHintIndex < (mfaRequired?.hints.count ?? 0) else { return }
+    guard selectedHintIndex < mfaRequired.hints.count else { return }
 
     Task {
       isLoading = true
@@ -128,7 +126,7 @@ extension MFAResolutionView: View {
       .padding(.horizontal)
 
       // MFA Hints Selection (if multiple available)
-      if let mfaRequired = mfaRequired, mfaRequired.hints.count > 1 {
+      if mfaRequired.hints.count > 1 {
         mfaHintsSelectionView(mfaRequired: mfaRequired)
       }
 
@@ -368,34 +366,36 @@ private extension MFAHint {
 #Preview("Phone SMS Only") {
   FirebaseOptions.dummyConfigurationForPreview()
   let authService = AuthService()
-  authService.currentMFARequired = MFARequired(hints: [
+  let mfaRequired = MFARequired(hints: [
     .phone(displayName: "Work Phone", uid: "phone-uid-1", phoneNumber: "+15551234567"),
   ])
-  return MFAResolutionView().environment(authService)
+  return MFAResolutionView(mfaRequired: mfaRequired).environment(authService)
 }
 
 #Preview("TOTP Only") {
   FirebaseOptions.dummyConfigurationForPreview()
   let authService = AuthService()
-  authService.currentMFARequired = MFARequired(hints: [
+  let mfaRequired = MFARequired(hints: [
     .totp(displayName: "Authenticator App", uid: "totp-uid-1"),
   ])
-  return MFAResolutionView().environment(authService)
+  return MFAResolutionView(mfaRequired: mfaRequired).environment(authService)
 }
 
 #Preview("Multiple Methods") {
   FirebaseOptions.dummyConfigurationForPreview()
   let authService = AuthService()
-  authService.currentMFARequired = MFARequired(hints: [
+  let mfaRequired = MFARequired(hints: [
     .phone(displayName: "Mobile", uid: "phone-uid-1", phoneNumber: "+15551234567"),
     .totp(displayName: "Google Authenticator", uid: "totp-uid-1"),
   ])
-  return MFAResolutionView().environment(authService)
+  return MFAResolutionView(mfaRequired: mfaRequired).environment(authService)
 }
 
-#Preview("No MFA Required") {
+#Preview("Single TOTP") {
   FirebaseOptions.dummyConfigurationForPreview()
   let authService = AuthService()
-  // currentMFARequired is nil by default
-  return MFAResolutionView().environment(authService)
+  let mfaRequired = MFARequired(hints: [
+    .totp(displayName: "Authenticator", uid: "totp-uid-1"),
+  ])
+  return MFAResolutionView(mfaRequired: mfaRequired).environment(authService)
 }

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Views/UpdatePasswordView.swift

@@ -53,7 +53,6 @@ public struct UpdatePasswordView {
 
 extension UpdatePasswordView: View {
   public var body: some View {
-    @Bindable var passwordPrompt = authService.passwordPrompt
     VStack(spacing: 24) {
       AuthTextField(
         text: $password,
@@ -115,9 +114,6 @@ extension UpdatePasswordView: View {
     } message: {
       Text("Your password has been successfully updated.")
     }
-    .sheet(isPresented: $passwordPrompt.isPromptingPassword) {
-      PasswordPromptSheet(coordinator: authService.passwordPrompt)
-    }
   }
 }
 

samples/swiftui/FirebaseSwiftUISample/FirebaseSwiftUISample/Application/ContentView.swift

@@ -25,7 +25,7 @@ import FirebaseOAuthSwiftUI
 
 struct ContentView: View {
   init() {
-     Auth.auth().useEmulator(withHost: "127.0.0.1", port: 9099)
+//     Auth.auth().useEmulator(withHost: "127.0.0.1", port: 9099)
 
     let actionCodeSettings = ActionCodeSettings()