MyApp class

Root widget that configures the app's theme and dependency injection.

Sets up a MultiProvider chain that:

1. Listens to FirebaseAuth.authStateChanges via StreamProvider<User?>
2. Wires User changes into AppState via ChangeNotifierProxyProvider<User?, AppState>
3. Configures Material 3 theme with teal color scheme
4. Sets up GoRouter for navigation with auth guards

Dependency Injection Structure

The provider hierarchy allows all descendant widgets to access:

• Current User via context.watch<User?>()
• AppState via context.watch<AppState>()

Provider Chain Details

StreamProvider

Streams FirebaseAuth user changes to the widget tree. Listens to FirebaseAuth.instance.authStateChanges() which emits:

• A User object when login succeeds
• null when logout occurs
• Initial state on app startup

The initialData: null ensures the app shows login screen before Firebase completes the first auth check.

ChangeNotifierProxyProvider

Syncs User changes into AppState for app-wide state management. This creates a dependency relationship where AppState depends on the StreamProvider<User?>.

When User changes:

1. AppState.updateUser is called with the new User
2. AppState clears or loads data based on login/logout
3. All widgets watching AppState rebuild automatically

The create callback initializes AppState once on first build. The update callback runs whenever User changes.

Theme Configuration

Uses Material 3 design with teal as the primary color seed. The theme is automatically generated from ColorScheme based on the seed color.

Navigation Setup

Uses MaterialApp.router with GoRouter configured in router for:

• Deep linking support
• Auth-based route guards
• Declarative navigation