import 'dart:async';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'auth_service.dart';
import 'auth_state.dart';
import 'auth_user.dart';

/// Provider for the underlying AuthService instance.
/// Can be overridden in tests with a mock or fake AuthService.
final authServiceProvider = Provider<AuthService>((ref) {
  final service = FirebaseAuthService();
  ref.onDispose(() => service.dispose());
  return service;
});

/// Reactive StateNotifier managing the authentication state for the UI
class AuthNotifier extends StateNotifier<AuthState> {
  final AuthService _authService;
  StreamSubscription<AuthState>? _subscription;

  AuthNotifier(this._authService) : super(_authService.currentState) {
    _subscription = _authService.authStateChanges.listen((state) {
      this.state = state;
    });
  }

  Future<void> signInWithEmailAndPassword(String email, String password) async {
    await _authService.signInWithEmailAndPassword(email, password);
    state = _authService.currentState;
  }

  Future<void> createUserWithEmailAndPassword(
    String email,
    String password, {
    String? displayName,
  }) async {
    await _authService.createUserWithEmailAndPassword(
      email,
      password,
      displayName: displayName,
    );
    state = _authService.currentState;
  }

  Future<void> signInWithGoogle() async {
    await _authService.signInWithGoogle();
    state = _authService.currentState;
  }

  Future<void> signInAnonymously() async {
    await _authService.signInAnonymously();
    state = _authService.currentState;
  }

  Future<void> sendPasswordResetEmail(String email) async {
    await _authService.sendPasswordResetEmail(email);
    state = _authService.currentState;
  }

  Future<void> signOut() async {
    await _authService.signOut();
    state = _authService.currentState;
  }

  void clearError() {
    state = state.copyWith(clearError: true);
  }

  @override
  void dispose() {
    _subscription?.cancel();
    super.dispose();
  }
}

/// Primary Riverpod provider for UI reactivity on authentication
final authNotifierProvider = StateNotifierProvider<AuthNotifier, AuthState>((ref) {
  final service = ref.watch(authServiceProvider);
  return AuthNotifier(service);
});

/// Convenience provider returning the active AuthUser or null
final currentUserProvider = Provider<AuthUser?>((ref) {
  return ref.watch(authNotifierProvider).user;
});

/// Convenience provider returning whether a non-anonymous user is signed in
final isAuthenticatedProvider = Provider<bool>((ref) {
  return ref.watch(authNotifierProvider).isAuthenticated;
});

/// Convenience provider returning whether the user is in anonymous/local mode
final isAnonymousUserProvider = Provider<bool>((ref) {
  return ref.watch(authNotifierProvider).isAnonymous;
});