class PhotosLibraryApiModel extends Model {
  PhotosLibraryApiModel() {
    _googleSignIn.onCurrentUserChanged.listen((GoogleSignInAccount account) {
      _currentUser = account;

      if (_currentUser != null) {
        // Initialize the client with the new user credentials
        client = PhotosLibraryApiClient(_currentUser.authHeaders);
      } else {
        // Reset the client
        client = null;
      }
      // Reinitialize the albums
      updateAlbums();

      notifyListeners();
    });
  }

  final LinkedHashSet<Album> _albums = LinkedHashSet<Album>();
  bool hasAlbums = false;
  PhotosLibraryApiClient client;

  GoogleSignInAccount _currentUser;

  final GoogleSignIn _googleSignIn = GoogleSignIn(scopes: <String>[
    'profile',
    'https://www.googleapis.com/auth/photoslibrary',
    'https://www.googleapis.com/auth/photoslibrary.sharing'
  ]);
  GoogleSignInAccount get user => _currentUser;

  bool isLoggedIn() {
    return _currentUser != null;
  }

  Future<bool> signIn() async {
    final GoogleSignInAccount user = await _googleSignIn.signIn();

    if (user == null) {
      // User could not be signed in
      print('User could not be signed in.');
      return false;
    }

    print('User signed in.');
    return true;
  }