import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'package:matrix/matrix.dart';

/// The one Matrix client, created in main() before the app starts.
final clientProvider = Provider<Client>(
  (ref) => throw UnimplementedError('overridden in main()'),
);

/// Signed in or not. Starts from the restored session.
final loginStateProvider = StreamProvider<LoginState>((ref) async* {
  final client = ref.watch(clientProvider);
  yield client.isLogged() ? LoginState.loggedIn : LoginState.loggedOut;
  yield* client.onLoginStateChanged.stream;
});

/// Bumps on every sync. The SDK's objects change in place, so screens that
/// show rooms watch this and read the client again; that is the whole
/// trick that keeps them current.
final syncProvider = StreamProvider<int>((ref) async* {
  final client = ref.watch(clientProvider);
  var n = 0;
  yield n;
  await for (final _ in client.onSync.stream) {
    yield ++n;
  }
});

/// Whether the connection to the homeserver is working, from the sync
/// loop's status. Null until the first sync after start finishes.
final syncErrorProvider = StreamProvider<bool>((ref) async* {
  final client = ref.watch(clientProvider);
  await for (final status in client.onSyncStatus.stream) {
    if (status.status == SyncStatus.error) yield true;
    if (status.status == SyncStatus.finished) yield false;
  }
});

/// The theme the user picked: the system's, light or dark.
class ThemeModeNotifier extends Notifier<ThemeMode> {
  static const _key = 'warp.theme';
  static const _storage = FlutterSecureStorage();

  @override
  ThemeMode build() {
    _storage.read(key: _key).then((value) {
      final mode = ThemeMode.values.where((m) => m.name == value).firstOrNull;
      if (mode != null) state = mode;
    });
    return ThemeMode.system;
  }

  void set(ThemeMode mode) {
    state = mode;
    _storage.write(key: _key, value: mode.name);
  }
}

final themeModeProvider = NotifierProvider<ThemeModeNotifier, ThemeMode>(
  ThemeModeNotifier.new,
);

/// The space the room list shows, or null for all chats.
class SelectedSpaceNotifier extends Notifier<String?> {
  @override
  String? build() => null;

  void select(String? spaceId) => state = spaceId;
}

final selectedSpaceProvider = NotifierProvider<SelectedSpaceNotifier, String?>(
  SelectedSpaceNotifier.new,
);