import 'dart:io';
import 'config.dart';

int createdConnectionCount = 0;
int runningConnectionCount = 0;
int upstreamBytes = 0;
int downstreamBytes = 0;
Map<int, bool> createdConnectionMap = <int, bool>{};

Future<void> main(List<String> arguments) async {
  print('Arguments: ' + arguments.toString());
  final proxyConfig = await loadProxyConfig(arguments[0]);

  for (final tcpListen in proxyConfig.tcpListens) {
    final listen = parseHostAndPort(tcpListen.listen);
    final target = parseHostAndPort(tcpListen.backend);
    startListen(listen, target);
  }
}

void startListen(HostAndPort listen, HostAndPort target) {
  ServerSocket.bind(listen.host, listen.port).then((serverSocket) {
    serverSocket.listen((Socket socket) {
      Socket.connect(target.host, target.port).then((clientSocket) {
        final createdConnectionIndex = createdConnectionCount;
        createdConnectionCount++;
        runningConnectionCount++;
        createdConnectionMap[createdConnectionIndex] = true;
        socket.listen(
          (event) {
            upstreamBytes += event.lengthInBytes;
            clientSocket.write(event);
          },
          onError: (error, StackTrace stackTrace) {
            if (createdConnectionMap.remove(createdConnectionIndex) != null) {
              runningConnectionCount--;
            }
            print(
                'Error in connection: ' + error + " " + stackTrace.toString());
          },
          onDone: () {
            if (createdConnectionMap.remove(createdConnectionIndex) != null) {
              runningConnectionCount--;
            }
            clientSocket.destroy();
          },
          cancelOnError: true,
        );

        clientSocket.listen(
          (event) {
            downstreamBytes += event.lengthInBytes;
            socket.write(event);
          },
          onError: (error, StackTrace stackTrace) {
            if (createdConnectionMap.remove(createdConnectionIndex) != null) {
              runningConnectionCount--;
            }
            print(
                'Error in connection: ' + error + " " + stackTrace.toString());
          },
          onDone: () {
            if (createdConnectionMap.remove(createdConnectionIndex) != null) {
              runningConnectionCount--;
            }
            socket.destroy();
          },
          cancelOnError: true,
        );
      });
    });
  });
}