import 'dart:async';
import 'package:nsd/nsd.dart';

abstract class IDiscoveryService {
  Future<void> registerService(int port);
  Future<void> stopRegistration();
  Stream<List<Service>> discoverServices();
}

class DiscoveryService implements IDiscoveryService {
  Registration? _registration;
  final String _serviceType = '_http._tcp';
  final String _serviceName = 'FastWatcher';

  @override
  Future<void> registerService(int port) async {
    _registration = await register(
      Service(
        name: _serviceName,
        type: _serviceType,
        port: port,
      ),
    );
  }

  @override
  Future<void> stopRegistration() async {
    if (_registration != null) {
      await unregister(_registration!);
      _registration = null;
    }
  }

  @override
  Stream<List<Service>> discoverServices() async* {
    final discovery = await startDiscovery(_serviceType);
    final controller = StreamController<List<Service>>();
    
    void update() {
      controller.add(discovery.services);
    }

    discovery.addListener(update);
    
    yield* controller.stream;
    
    // Note: In a real app, handle disposal
  }
}