import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'dart:typed_data';
import 'little_extension.dart';
import 'code.dart';

class SocketUtils extends Socket{
  // 私有构造函数
  SocketUtils._();
  // 私有静态变量，保存类的唯一实例
  static SocketUtils? _instance;

  // 公开的静态方法，返回类的唯一实例
  static SocketUtils getInstance() {
    _instance ??= SocketUtils._();
    return _instance!;
  }

}

class Socket {

  static String url = '127.0.0.1';
  static int port = 12345;

  RawDatagramSocket? socket;

  // IC 0主机 1 从机
  int ic = 1;

  connect() async {
    socket = await RawDatagramSocket.bind('127.0.0.3', 1);
    print('UDP Socket bound to ${socket?.address.address}:${socket?.port}');

    // 发送身份包
    Map data = {
      "op": 0,
      "IC": ic
    };
    socket?.send(dataMake(data), InternetAddress(url), port);

    // 监听来自网络的数据包
    socket?.listen((RawSocketEvent e) {
      Datagram? d = socket?.receive();
      if (d == null) return;
      print(d.data.toList());
      // String message = String.fromCharCodes(d.data).trim();

      Map data = dataCute(d.data);


    });

  }

  /// 发送消息
  sendMessage(Map data){
    Map messageMap = {
      "op": 2,
      "value": data
    };
    socket?.send(dataMake(messageMap), InternetAddress(url), port);
  }


  /// 心跳
  heartbeat(){
    Timer timer = Timer(const Duration(seconds: 10), () async {

      if (socket == null){
        // 重连
        await connect();
      }

      Map data =   {
        "op": 1,
        "IC": ic
      };
      socket?.send(dataMake(data), InternetAddress(url), port);

      heartbeat();
    });
  }

  /// 发送数据的处理
  List<int> dataMake(Map map){
    // 将Map对象转换为JSON字符串
    String json = jsonEncode(map);
    // 加密
    String ps = makecode(json, skey);
    // 转成无符号整数数组
    Uint8List uinData = Uint8List.fromList(ps.codeUnits);
    // 在前面添加 4位 表示长度的小端序
    uinData = uinData.toLittle(value: uinData.length);
    return uinData.toList();
  }

  /// 接收数据处理
  Map dataCute(Uint8List data){

    if (data.length <= 4) return {};

    Uint8List pData = data.sublist(4,data.length);

    // String ps = String.fromCharCodes(pData);

    String str = cutecode(pData);
    print(str);

    Map map = json.decode(str);

    return map;
  }

}