fix: allow user to set their own callback for phone auth

FirebaseSwiftUI/FirebaseAppleSwiftUI/Sources/Views/SignInWithAppleButton.swift

@@ -21,6 +21,7 @@ import SwiftUI
 public struct SignInWithAppleButton {
   @Environment(AuthService.self) private var authService
   @Environment(\.accountConflictHandler) private var accountConflictHandler
+  @Environment(\.mfaHandler) private var mfaHandler
   @Environment(\.reportError) private var reportError
   let provider: AppleProviderSwift
   public init(provider: AppleProviderSwift) {
@@ -37,7 +38,14 @@ extension SignInWithAppleButton: View {
     ) {
       Task {
         do {
-          _ = try await authService.signIn(provider)
+          let outcome = try await authService.signIn(provider)
+
+          // Handle MFA at view level
+          if case let .mfaRequired(mfaInfo) = outcome,
+             let onMFA = mfaHandler {
+            onMFA(mfaInfo)
+            return
+          }
         } catch {
           reportError?(error)
 

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Services/AuthService.swift

@@ -141,6 +141,7 @@ public final class AuthService {
   private var listenerManager: AuthListenerManager?
 
   var emailSignInEnabled = false
+  private var emailSignInCallback: (@MainActor () -> Void)?
 
   private var providers: [AuthProviderUI] = []
 
@@ -151,12 +152,18 @@ public final class AuthService {
   public func renderButtons(spacing: CGFloat = 16) -> AnyView {
     AnyView(
       VStack(spacing: spacing) {
-        AuthProviderButton(
-          label: string.signInWithEmailLinkViewTitle,
-          style: .email,
-          accessibilityId: "sign-in-with-email-link-button"
-        ) {
-          self.navigator.push(.emailLink)
+        if emailSignInEnabled {
+          AuthProviderButton(
+            label: string.signInWithEmailLinkViewTitle,
+            style: .email,
+            accessibilityId: "sign-in-with-email-link-button"
+          ) {
+            if let callback = self.emailSignInCallback {
+              callback()
+            } else {
+              self.navigator.push(.emailLink)
+            }
+          }
         }
         ForEach(providers, id: \.id) { provider in
           provider.authButton()
@@ -309,8 +316,17 @@ public extension AuthService {
 // MARK: - Email/Password Sign In
 
 public extension AuthService {
+  /// Enable email sign-in with default behavior (navigates to email link view)
   func withEmailSignIn() -> AuthService {
+    return withEmailSignIn { [weak self] in
+      self?.navigator.push(.emailLink)
+    }
+  }
+
+  /// Enable email sign-in with custom callback
+  func withEmailSignIn(onTap: @escaping @MainActor () -> Void) -> AuthService {
     emailSignInEnabled = true
+    emailSignInCallback = onTap
     return self
   }
 
@@ -865,7 +881,6 @@ public extension AuthService {
     let hints = extractMFAHints(from: resolver)
     currentMFARequired = MFARequired(hints: hints)
     currentMFAResolver = resolver
-    navigator.push(.mfaResolution)
     return .mfaRequired(MFARequired(hints: hints))
   }
 

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Views/AccountConflictModifier.swift

@@ -32,6 +32,7 @@ public extension EnvironmentValues {
 @MainActor
 struct AccountConflictModifier: ViewModifier {
   @Environment(AuthService.self) private var authService
+  @Environment(\.mfaHandler) private var mfaHandler
   @Environment(\.reportError) private var reportError
   @State private var pendingCredentialForLinking: AuthCredential?
 
@@ -56,7 +57,13 @@ struct AccountConflictModifier: ViewModifier {
           try await authService.signOut()
 
           // Sign in with the new credential
-          _ = try await authService.signIn(credentials: conflict.credential)
+          let outcome = try await authService.signIn(credentials: conflict.credential)
+
+          // Handle MFA at view level
+          if case let .mfaRequired(mfaInfo) = outcome,
+             let onMFA = mfaHandler {
+            onMFA(mfaInfo)
+          }
         } catch {
           // Report error to parent view for display
           reportError?(error)

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Views/AuthPickerView.swift

@@ -76,6 +76,8 @@ extension AuthPickerView: View {
         .interactiveDismissDisabled(authService.configuration.interactiveDismissEnabled)
         // Apply account conflict handling at NavigationStack level
         .accountConflictHandler()
+        // Apply MFA handling at NavigationStack level
+        .mfaHandler()
       }
   }
 

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Views/EmailAuthView.swift

@@ -33,6 +33,7 @@ private enum FocusableField: Hashable {
 public struct EmailAuthView {
   @Environment(AuthService.self) private var authService
   @Environment(\.accountConflictHandler) private var accountConflictHandler
+  @Environment(\.mfaHandler) private var mfaHandler
   @Environment(\.reportError) private var reportError
 
   @State private var email = ""
@@ -53,7 +54,14 @@ public struct EmailAuthView {
 
   private func signInWithEmailPassword() async throws {
     do {
-      _ = try await authService.signIn(email: email, password: password)
+      let outcome = try await authService.signIn(email: email, password: password)
+
+      // Handle MFA at view level
+      if case let .mfaRequired(mfaInfo) = outcome,
+         let onMFA = mfaHandler {
+        onMFA(mfaInfo)
+        return
+      }
     } catch {
       reportError?(error)
 
@@ -69,7 +77,14 @@ public struct EmailAuthView {
 
   private func createUserWithEmailPassword() async throws {
     do {
-      _ = try await authService.createUser(email: email, password: password)
+      let outcome = try await authService.createUser(email: email, password: password)
+
+      // Handle MFA at view level
+      if case let .mfaRequired(mfaInfo) = outcome,
+         let onMFA = mfaHandler {
+        onMFA(mfaInfo)
+        return
+      }
     } catch {
       reportError?(error)
 

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Views/MFAHandlerModifier.swift

@@ -0,0 +1,54 @@
+// 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
+import SwiftUI
+
+/// Environment key for accessing the MFA handler
+public struct MFAHandlerKey: @preconcurrency EnvironmentKey {
+  @MainActor public static let defaultValue: ((MFARequired) -> Void)? = nil
+}
+
+public extension EnvironmentValues {
+  var mfaHandler: ((MFARequired) -> Void)? {
+    get { self[MFAHandlerKey.self] }
+    set { self[MFAHandlerKey.self] = newValue }
+  }
+}
+
+/// View modifier that handles MFA requirements at the view layer
+/// Automatically navigates to MFA resolution when MFA is required
+@MainActor
+struct MFAHandlerModifier: ViewModifier {
+  @Environment(AuthService.self) private var authService
+
+  func body(content: Content) -> some View {
+    content
+      .environment(\.mfaHandler, handleMFARequired)
+  }
+
+  /// Handle MFA required - navigate to MFA resolution view
+  func handleMFARequired(_: MFARequired) {
+    authService.navigator.push(.mfaResolution)
+  }
+}
+
+extension View {
+  /// Adds MFA handling to the view hierarchy
+  /// Should be applied at the NavigationStack level to handle MFA requirements throughout the auth
+  /// flow
+  func mfaHandler() -> some View {
+    modifier(MFAHandlerModifier())
+  }
+}

FirebaseSwiftUI/FirebaseFacebookSwiftUI/Sources/Views/SignInWithFacebookButton.swift

@@ -23,6 +23,7 @@ import SwiftUI
 public struct SignInWithFacebookButton {
   @Environment(AuthService.self) private var authService
   @Environment(\.accountConflictHandler) private var accountConflictHandler
+  @Environment(\.mfaHandler) private var mfaHandler
   @Environment(\.reportError) private var reportError
   let facebookProvider: FacebookProviderSwift
 
@@ -40,7 +41,14 @@ extension SignInWithFacebookButton: View {
     ) {
       Task {
         do {
-          _ = try await authService.signIn(facebookProvider)
+          let outcome = try await authService.signIn(facebookProvider)
+
+          // Handle MFA at view level
+          if case let .mfaRequired(mfaInfo) = outcome,
+             let onMFA = mfaHandler {
+            onMFA(mfaInfo)
+            return
+          }
         } catch {
           reportError?(error)
 

FirebaseSwiftUI/FirebaseGoogleSwiftUI/Sources/Views/SignInWithGoogleButton.swift

@@ -27,6 +27,7 @@ import SwiftUI
 public struct SignInWithGoogleButton {
   @Environment(AuthService.self) private var authService
   @Environment(\.accountConflictHandler) private var accountConflictHandler
+  @Environment(\.mfaHandler) private var mfaHandler
   @Environment(\.reportError) private var reportError
   let googleProvider: GoogleProviderSwift
 
@@ -44,7 +45,14 @@ extension SignInWithGoogleButton: View {
     ) {
       Task {
         do {
-          _ = try await authService.signIn(googleProvider)
+          let outcome = try await authService.signIn(googleProvider)
+
+          // Handle MFA at view level
+          if case let .mfaRequired(mfaInfo) = outcome,
+             let onMFA = mfaHandler {
+            onMFA(mfaInfo)
+            return
+          }
         } catch {
           reportError?(error)
 

FirebaseSwiftUI/FirebaseOAuthSwiftUI/Sources/Views/GenericOAuthButton.swift

@@ -21,6 +21,7 @@ import SwiftUI
 public struct GenericOAuthButton {
   @Environment(AuthService.self) private var authService
   @Environment(\.accountConflictHandler) private var accountConflictHandler
+  @Environment(\.mfaHandler) private var mfaHandler
   @Environment(\.reportError) private var reportError
   let provider: OAuthProviderSwift
   public init(provider: OAuthProviderSwift) {
@@ -47,7 +48,14 @@ extension GenericOAuthButton: View {
       ) {
         Task {
           do {
-            _ = try await authService.signIn(provider)
+            let outcome = try await authService.signIn(provider)
+
+            // Handle MFA at view level
+            if case let .mfaRequired(mfaInfo) = outcome,
+               let onMFA = mfaHandler {
+              onMFA(mfaInfo)
+              return
+            }
           } catch {
             reportError?(error)
 

FirebaseSwiftUI/FirebasePhoneAuthSwiftUI/Sources/Services/AuthService+Phone.swift

@@ -22,9 +22,18 @@
 import FirebaseAuthSwiftUI
 
 public extension AuthService {
+  /// Register phone sign-in with default behavior (navigates to enter phone number view)
   @discardableResult
   func withPhoneSignIn() -> AuthService {
-    registerProvider(providerWithButton: PhoneAuthProviderAuthUI())
+    return withPhoneSignIn { [weak self] in
+      self?.navigator.push(.enterPhoneNumber)
+    }
+  }
+
+  /// Register phone sign-in with custom behavior
+  @discardableResult
+  func withPhoneSignIn(onTap: @escaping @MainActor () -> Void) -> AuthService {
+    registerProvider(providerWithButton: PhoneAuthProviderAuthUI(onTap: onTap))
     return self
   }
 }

FirebaseSwiftUI/FirebasePhoneAuthSwiftUI/Sources/Services/PhoneAuthProviderAuthUI.swift

@@ -25,11 +25,15 @@ public class PhoneAuthProviderAuthUI: AuthProviderUI {
   public var provider: AuthProviderSwift { typedProvider }
   public let id: String = "phone"
 
-  public init() {
+  // Callback for when the phone auth button is tapped
+  private let onTap: @MainActor () -> Void
+
+  public init(onTap: @escaping @MainActor () -> Void) {
     typedProvider = PhoneProviderSwift()
+    self.onTap = onTap
   }
 
   @MainActor public func authButton() -> AnyView {
-    AnyView(PhoneAuthButtonView())
+    AnyView(PhoneAuthButtonView(onTap: onTap))
   }
 }

FirebaseSwiftUI/FirebasePhoneAuthSwiftUI/Sources/Views/PhoneAuthButtonView.swift

@@ -20,8 +20,11 @@ import SwiftUI
 @MainActor
 public struct PhoneAuthButtonView {
   @Environment(AuthService.self) private var authService
+  private let onTap: @MainActor () -> Void
 
-  public init() {}
+  public init(onTap: @escaping @MainActor () -> Void) {
+    self.onTap = onTap
+  }
 }
 
 extension PhoneAuthButtonView: View {
@@ -31,13 +34,15 @@ extension PhoneAuthButtonView: View {
       style: .phone,
       accessibilityId: "sign-in-with-phone-button"
     ) {
-      authService.navigator.push(.enterPhoneNumber)
+      onTap()
     }
   }
 }
 
 #Preview {
   FirebaseOptions.dummyConfigurationForPreview()
-  return PhoneAuthButtonView()
-    .environment(AuthService())
+  return PhoneAuthButtonView {
+    print("Phone auth tapped")
+  }
+  .environment(AuthService())
 }

FirebaseSwiftUI/FirebaseTwitterSwiftUI/Sources/Views/SignInWithTwitterButton.swift

@@ -21,6 +21,7 @@ import SwiftUI
 public struct SignInWithTwitterButton {
   @Environment(AuthService.self) private var authService
   @Environment(\.accountConflictHandler) private var accountConflictHandler
+  @Environment(\.mfaHandler) private var mfaHandler
   @Environment(\.reportError) private var reportError
   let provider: TwitterProviderSwift
   public init(provider: TwitterProviderSwift) {
@@ -37,7 +38,14 @@ extension SignInWithTwitterButton: View {
     ) {
       Task {
         do {
-          _ = try await authService.signIn(provider)
+          let outcome = try await authService.signIn(provider)
+
+          // Handle MFA at view level
+          if case let .mfaRequired(mfaInfo) = outcome,
+             let onMFA = mfaHandler {
+            onMFA(mfaInfo)
+            return
+          }
         } catch {
           reportError?(error)