owntracks-viewer/lib/web_socket_cubit.dart

// web_socket_cubit.dart
import 'dart:async';
import 'dart:convert';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:ot_viewer_app/owntracks_api.dart';
import 'package:ot_viewer_app/settings_page.dart';
import 'package:ws/ws.dart';
import 'package:rust_core/option.dart';

// Define the state. For simplicity, we're just using Map<String, dynamic> directly.
// You might want to define a more specific state class based on your application's needs.
abstract class LocationUpdateState {}

class LocationUpdateUnconnected extends LocationUpdateState {}

class LocationUpdateConnected extends LocationUpdateState {}

class LocationUpdateReceived extends LocationUpdateState {
  Point position;
  (String, String) deviceId;

  LocationUpdateReceived(this.position, this.deviceId);
}

class LocationSubscribeCubit extends Cubit<LocationUpdateState> {
  Option<WebSocketClient> _wsClient = None;
  String url = '';
  String username = '';
  String pass = '';

  LocationSubscribeCubit() : super(LocationUpdateUnconnected());

  subscribe(SettingsState settings) async {
    
    // check if resubscribe is necessary (different URL)
    if (settings.url == url && settings.username == username && settings.password == pass) {
      return;
    } else {
      url = settings.url;
      username = settings.username;
      pass = settings.password;
    }
    
    await _wsConnectionEstablish();
  }

  Future<void> _wsConnectionEstablish() async {
    if (_wsClient.isSome()) {
      await _wsClient.unwrap().close();
      _wsClient = None;
    }
    
    var ws = await OwntracksApi(baseUrl: url, username: username, pass: pass)
        .createWebSocketConnection(
      wsPath: 'last',
      onMessage: (msg) {
        if (msg is String) {
          if (msg == 'LAST') {
            return;
          }
          try {
            final Map<String, dynamic> map = jsonDecode(msg);
    
            if (map['_type'] == 'location') {
              // filter points (only the ones for this device pls!)
              final topic = (map['topic'] as String?)?.split('/');
              if (topic == null || topic.length < 3) {
                // couldn't reconstruct ID, bail
                return;
              }
    
              // build device_id
              final deviceId = (topic[1], topic[2]);
    
              print(map);
    
              // build point
              final p = Point(
                  lat: map['lat'] as double,
                  lon: map['lon'] as double,
                  timestamp: DateTime.fromMillisecondsSinceEpoch((map['tst'] as int) * 1000));
    
              print(p);
    
              emit(LocationUpdateReceived(p, deviceId));
            }
          } catch (e) {
            print('BUG: Couldn\'t parse WS message: $msg ($e)');
          }
        }
      },
      onStateChange: (sc) {
        switch (sc) {
          case WebSocketClientState$Open(:final url):
            _wsClient.map((wsc) => wsc.add('LAST'));
            emit(LocationUpdateConnected());
            break;
          default:
            emit(LocationUpdateUnconnected());
            break;
        }
        print(sc);
      },
    );
    
    _wsClient = ws.expect("Estabilshing Websocket Conenction failed").toOption();
  }

  @override
  void onChange(Change<LocationUpdateState> change) {
    print('loc_sub_cubit change: $change');
  }

  @override
  Future<void> close() async {
    await _wsClient.toFutureOption().map((conn) => conn.close());
    return super.close();
  }
}