dart-app-core/lib/socket/protobuf_client.dart

// ignore_for_file: avoid_init_to_null, prefer_final_fields, avoid_print

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

import 'package:dart_framework/utils/system_util.dart';
import 'package:protobuf/protobuf.dart';
import 'package:dart_framework/communicator.dart';
import 'package:dart_framework/socket/packets/message_common.pb.dart';

abstract class ProtobufClient extends Communicator
{
  final int _headerSize = 4;
  late int _heartbeatIntervalTime;
  late int _heartbeatWaitTime;
  final Socket _socket;
  late ResponseChecker? _heartbeatChecker = null;
  int? _length = null;
  bool _isAlive = false;
  late List<int> _arrivedData = [];
  List<void Function(ProtobufClient)> _onDisconnectListenerList = [];

  
  ProtobufClient(this._socket, this._heartbeatIntervalTime, this._heartbeatWaitTime, Map<String, GeneratedMessage Function(List<int>)> parserMap) {
    print('Connected New Client');
    _isAlive = true;
    parserMap.addAll({
      (TestData).toString() : TestData.fromBuffer,
      (HeartBeat).toString() : HeartBeat.fromBuffer
    });
    super.initialize(parserMap);
    _socket.listen(onData, onError: onError)
            .asFuture().then(onDisconnected);
    addListener(onHeartBeat);
    sendHeartBeat();
  }

  void sendHeartBeat() {
    if(_isAlive) {
      _heartbeatChecker?.responsed();
      _heartbeatChecker = ResponseChecker.second(this, _heartbeatIntervalTime, (client) {
        if(_isAlive) {
          send(HeartBeat());
          _heartbeatChecker = ResponseChecker.second(this, _heartbeatWaitTime, (client) {
            if(_isAlive) {
              dispose();
              onDisconnected(null);
            }
          });
        }
      });
    }
  }

  void onHeartBeat(HeartBeat data) {
    print('=== onHeartBeat');
  }

  void addDisconnectListener(void Function(ProtobufClient) handler) {
    if(!_onDisconnectListenerList.contains(handler))
    {
      _onDisconnectListenerList.add(handler);
    }
  }

  void removeDisconnectListener(void Function(ProtobufClient) handler) {
    if(_onDisconnectListenerList.contains(handler))
    {
      _onDisconnectListenerList.remove(handler);
    }
  }

  void onDisconnected(dynamic data) {
    //client disconnected
    if(_isAlive)
    {
      for (var item in _onDisconnectListenerList) {
        item.call(this);
      }
      _onDisconnectListenerList.clear();
    }
  }

  void onError(dynamic e) {
    print('=========> onError: $e');
  }

  void onData(Uint8List data) async {
    try
    {
      // printPacket('## Received', data);
      if(_length == null)
      {
        var header = data.sublist(0, _headerSize);
        _length = header.buffer.asByteData().getInt32(0);
        _arrivedData.addAll(data.sublist(_headerSize));
      }
      else
      {
        _arrivedData.addAll(data);
      }

      if(_arrivedData.length == _length)
      {
        var common = PacketBase.fromBuffer(_arrivedData);
        var nonce = common.nonce;
        onReceivedData(common.typeName, common.data);
        _length = null;
        _arrivedData.clear();

        sendHeartBeat();
      }
    } on Exception catch(e) {
      print(e);
    }
  }

  @override
  Future send<T extends GeneratedMessage>(T data) async {
    if(_isAlive) {
      try {
        List<int> packet = [];
        var base = PacketBase();
        base.typeName = data.info_.qualifiedMessageName;
        base.nonce = 0;
        base.data = data.writeToBuffer();
        var baseBytes = base.writeToBuffer();
        int length = baseBytes.length + _headerSize;
        var header = Uint8List(_headerSize)
                      ..buffer.asByteData().setInt32(0, length);
        packet.addAll(header);
        packet.addAll(baseBytes);

        // printPacket('Send', packet);

        _socket.add(packet);
        await _socket.flush();
      } catch(e, s) {
        onDisconnected(null);
      }
    }
    return simpleFuture;
  }

  void printPacket(String prefix, List<int> packet) {
    var s = StringBuffer();
    for(var item in packet)
    {
      s.write('$item, ');
    }
    print('$prefix: ${s.toString()}');
  }

  void dispose() async {
    if(_isAlive)
    {
      _isAlive = false;
      _heartbeatChecker?.responsed();
      try {
        await _socket.close();
        _socket.destroy();
      } catch (e, s) {}
    }
  }
}

class ResponseChecker<T> {
  final T _responser;
  late int _time;
  late Timer? _timer = null;
  late void Function(T) _notResponseListener;
  T get responser => _responser;
  ResponseChecker(this._responser, this._time, this._notResponseListener) {
    startTimer();
  }

  ResponseChecker.second(this._responser, int time, this._notResponseListener) {
    this._time = time * 1000;
    startTimer();
  }

  void startTimer() {
    _timer = Timer(Duration(milliseconds: _time), () {
      _notResponseListener(_responser);
    });
  }

  T responsed() {
    _timer?.cancel();
    _timer = null;
    return _responser;
  }
}