import 'dart:async';
import 'dart:io';

import 'package:shelf/shelf.dart';
import 'package:shelf/shelf_io.dart' as shelf_io;
import 'package:shelf_router/shelf_router.dart';
import 'package:shelf_web_socket/shelf_web_socket.dart';

final List<dynamic> clients = [];

// Configure routes.
final _router = Router()
  ..get('/', _rootHandler)
  ..get('/echo/<message>', _echoHandler);

Response _rootHandler(Request req) {
  return Response.ok('Hello, World!\n');
}

Response _echoHandler(Request request) {
  final message = request.params['message'];
  return Response.ok('$message\n');
}

void main(List<String> args) async {
  // Use any available host or container IP (usually `0.0.0.0`).
  final ip = InternetAddress.anyIPv4;

  // Configure a pipeline that logs requests.
  final handler = Pipeline().addMiddleware(logRequests()).addHandler(_router.call);

  var wsHandler = webSocketHandler((webSocket, _) {
    clients.add(webSocket);
    print('Client connected, total: ${clients.length}');

    webSocket.stream.listen(
      (message) {
        webSocket.sink.add('echo $message');
      },
      onDone: () {
        clients.remove(webSocket);
        print('Client disconnected, total: ${clients.length}');
      },
      onError: (error) {
        clients.remove(webSocket);
        print('Client error: $error');
      },
      cancelOnError: true,
    );
  });

  FutureOr<Response> combinedHandler(Request request) {
    if (request.url.path == 'ws') {
      return wsHandler(request);
    }
    return handler(request);
  }

  // For running in containers, we respect the PORT environment variable.
  final port = int.parse(Platform.environment['PORT'] ?? '8080');
  final server = await shelf_io.serve(combinedHandler, ip, port).then((server) {
    print('Serving at http|ws://${server.address.host}:${server.port}');
  });
}

// Broadcast to all clients
void broadcast(String message) {
  for (final client in clients) {
    client.sink.add(message);
  }
}