Phase 5: Authentication
Status: Complete iOS PRs: #338 (Dark Mode), #339 (Authentication), #340 (Apple Sign-In)
Overview
Phase 5 implements iOS authentication with Firebase, including Google Sign-In OAuth, Apple Sign-In, anonymous (guest) authentication, and dark mode settings.
Features
PR #338 - Dark Mode Toggle
- ThemeManager with @AppStorage persistence
- System/Light/Dark theme options
- Immediate visual feedback
- 14 TDD tests
PR #339 - Authentication Flow
- Google Sign-In OAuth
- Anonymous (guest) authentication
- Account upgrade from guest to Google
- Real-time auth state observation
- Swift-native Firebase implementation
- 14 TDD tests
PR #340 - Apple Sign-In
- Native AuthenticationServices framework
- Cryptographic nonce security (SecRandomCopyBytes + SHA256)
- Continuation-based delegate → async/await bridging
- Firebase OAuthProvider credential exchange
- Race condition prevention
- iPad navigation fixes (NavigationStack)
- 6 TDD tests
Architecture
SignInView SettingsTabView
│ │
▼ ▼
SignInViewModel ThemeManager
│ │
▼ ▼
FirebaseAuthRepositoryBridge @AppStorage
│ (UserDefaults)
├── GoogleSignInProviderImpl
├── AppleSignInProviderImpl
└── Firebase Auth SDK
Key Files
| Component | File | Description |
|---|---|---|
| Auth Bridge | Auth/FirebaseAuthRepositoryBridge.swift | Swift-native Firebase |
| Google Provider | Auth/GoogleSignInProviderImpl.swift | Google OAuth tokens |
| Apple Provider | Auth/AppleSignInProviderImpl.swift | Apple Sign-In + nonce |
| Sign-In View | Screens/SignInView.swift | UI + ViewModel |
| Theme Manager | ThemeManager.swift | Dark mode |
| Settings View | Screens/SettingsTabView.swift | Theme picker |
Test Coverage
| Component | Tests | File |
|---|---|---|
| SignInViewModel | 20 | SignInViewModelTests.swift |
| ThemeManager | 14 | ThemeManagerTests.swift |
Total: 34 TDD tests
Key Patterns
- Swift-Native Firebase - Avoid KMP ObjCExportCoroutines issues
- Native Auth State Listener - Use Firebase SDK directly
- @AppStorage + objectWillChange - Proper SwiftUI observation
- Token Flow Optimization - Single signIn() returns both tokens
- Nonce Security - Prevent replay attacks with SHA256 verification
- Continuation Bridging - Delegate → async/await with CheckedContinuation
- NavigationStack - Avoid iPad split view issues
Documentation
- Authentication Implementation Guide - Google/Guest sign-in details
- Apple Sign-In Guide - Apple Sign-In implementation
Related Documentation
- iOS Troubleshooting - Common issues
- KMP iOS Patterns - Bridge patterns
- Phase 5 Analytics - Analytics features
Last Updated: 2025-12-02