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;

  connect() async {
    socket = await RawDatagramSocket.bind('127.0.0.2', 1);
    print('UDP Socket bound to ${socket?.address.address}:${socket?.port}');

    // 监听来自网络的数据包
    socket?.listen((RawSocketEvent e) {
      Datagram? d = socket?.receive();
      if (d == null) return;

      // String message = String.fromCharCodes(d.data).trim();
      // print('Datagram from ${d.address.address}:${d.port}: $message');
    });

    heartbeat();
  }

  /// 发送消息
  sendMessage(Map data){
    socket?.send(dataMake(data), InternetAddress(url), port);
  }


  /// 心跳
  heartbeat(){
    Timer timer = Timer(const Duration(seconds: 10), () {
      Map data =   {
        "op": 1,
        "IC": 0
      };
      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();
  }

}