// ignore_for_file: prefer_final_fields

import 'package:protobuf/protobuf.dart';

abstract class Communicator
{
  Map<String, IDataHandler> _handlerDic = {};
  late Map<String, GeneratedMessage Function(List<int>)> _instanceGenerator;

  Communicator();

  void initialize(Map<String, GeneratedMessage Function(List<int>)> instanceGenerator)
  {
    _instanceGenerator = instanceGenerator;
  }

  T Function(List<int>) getGenerator<T extends GeneratedMessage>(String type)
  {
    if(!_instanceGenerator.containsKey(type))
    {
      throw Exception('Must set protobuf packet creator before use it. Type: ${(T).toString()}');
    }
    return _instanceGenerator[type] as T Function(List<int>);
  }

  Future send<T extends GeneratedMessage>(T data);

  void onReceivedData(String typeName, List<int> data)
  {
    if( _handlerDic.containsKey(typeName) ) {
      _handlerDic[typeName]?.onMessage(data);
    }
  }

  void addListener<T extends GeneratedMessage>(void Function(T) listener)
  {
    var type = T.toString();
    if(!_handlerDic.containsKey(type))
    {
      _handlerDic[type] = DataHandler<T>(getGenerator(type));
    }
    var handler = _handlerDic[type] as DataHandler<T>;
    handler.addListener(listener);
  }

  void removeListener<T extends GeneratedMessage>(void Function(T) listener)
  {
    var type = T.toString();
    if(_handlerDic.containsKey(type))
    {
        var handler = _handlerDic[type] as DataHandler<T>;
        handler.removeListener(listener);
    }
  }
}

abstract class IDataHandler
{
  void onMessage(List<int> data);
}

class DataHandler<T extends GeneratedMessage> implements IDataHandler
{
  T Function(List<int>) _generator;
  List<void Function(T)> _listeners = [];

  DataHandler(this._generator);

  @override
  void onMessage(List<int> data)
  {
    for(var listener in _listeners)
    {
      listener.call(_generator(data));
    }
  }

  void addListener(void Function(T) handler)
  {
    removeListener(handler); //중복 리스너 불허
    _listeners.add(handler);
  }

  void removeListener(void Function(T) handler)
  {
      _listeners.remove(handler);
  }
}