const net = require('net');
const server = net.createServer();
const clients = {};//保存客户端的连接
var client = null;//当前客户连接
var uid = 0;
server.on('connection',(socket)=>{
 //启动心跳机制
 var isOnline = !0;
 var keepAliveTimer = socket.timer = setInterval(()=>{
  if(!isOnline){
   isOnline = !1;
   client = socket;
   quit(socket.nick);
   return;
  }
  if(socket.writable){
   socket.write('::');
  }else{
   client = socket;
   quit(socket.nick);
  }
 },3000);
 socket.on('end',()=>{
  console.log(`client disconnected.\n\r`);
  socket.destroy();
 });
 socket.on('error',(error)=>{
  console.log(error.message);
 });
 socket.on('data',(chunk)=>{
  client = socket;
  var msg = JSON.parse(chunk.toString());
  if(msg.cmd=='keep'){
   isOnline = !0;
   return;
  }
  dealMsg(msg);
 });
});
server.on('error',(err)=>{
 console.log(err);
});
server.on('listening',()=>{
 console.log(`listening on ${server.address().address}:${server.address().port}\n\r`);
});
server.listen(8060);//启动监听
/**
 * 处理用户信息
 */
function dealMsg(msg){
 const cmd = msg.cmd;
 const funs = {
  'login':login,
  'chat':chat,
  'quit':quit,
  'exit':quit
 };
 if(typeof funs[cmd] !== 'function') return !1;
 funs[cmd](msg);
}
/**
 * 释放连接资源
 */
function freeConn(conn){
 conn.end();
 delete clients[conn.uuid];
 conn.timer&&clearInterval(conn.timer);
}
/**
 * 用户首次进入聊天室
 */
function login(msg){
 var uuid = '';
 uuid = getRndStr(15)+(++uid);//产生用户ID
 client.write(`欢迎你，${msg.nick}：这里总共有${Object.keys(clients).length}个小伙伴在聊天.\r\n`)
 client.nick = msg.nick;
 client.uuid = uuid;
 clients[uuid] = client;
 broadcast(`系统：${msg.nick}进入了聊天室.`);

}
/**
 * 广播消息
 */
function broadcast(msg){
 Object.keys(clients).forEach((uuid)=>{
  if((clients[uuid]!=client)& clients[uuid].writable){
   clients[uuid].write(msg);
  }
 });
}
/**
 * 退出聊天室
 */
function quit(nick){
 var message = `小伙伴${nick}退出了聊天室.`;
 broadcast(message);
 freeConn(client);
}

function chat(msg){
 if(msg.msg.toLowerCase()=='quit'||msg.msg.toLowerCase()=='exit'){
  quit(msg.nick);
  return ;
 }
 var message = `${msg.nick}说：${msg.msg}`;
 broadcast(message);
} 
/**
 * 随机指定长度(len)的字符串
 */
function getRndStr(len=1){
 var rndStr = '';
 for (; rndStr.length < len; rndStr += Math.random().toString(36).substr(2));
 return rndStr.substr(0, len);
}

const net = require('net');
const cout = process.stdout;
const cin = process.stdin;

var client = null;
var nick = '';

cout.write(`请输入昵称：`);
//监听命令行输入
cin.on('data',(chunk)=>{
 if(chunk.toString()!='\r\n'){
  if(client === null){
   nick = (chunk+'').replace(/[\r\n]/ig,"");
   createClient();
  }else{
   msg = (chunk+'').replace(/[\r\n]/ig,"");
   client.write(JSON.stringify({
    cmd: 'chat',
    msg: msg,
    nick: nick
   }));
   //如果输入是exit或quit则断开连接并退出
   if(msg.toLowerCase() == 'exit' || msg.toLowerCase() == 'quit'){
    client.end();
    cin.end();
    return;
   }
   cout.write(`你说：${msg}\n\r`);
  }
 }else{
  cout.write(`请输入昵称：`);
 }
});

function addListener(client) {
 client.on('connect', () => {
  cout.write(`已连接到服务器\n\r`);
  client.write(JSON.stringify({
   cmd: 'login',
   msg: 'hello server',
   nick: nick
  }));
 });
 client.on('end', (chunk) => {
  cout.write(`与服务器断开连接.\n\r`);
 });
 client.on('data', (chunk) => {
  //如果是心跳信息则回应keep命令
  if(chunk.toString()=='::'){
   client.write(JSON.stringify({
    cmd: 'keep',
    msg: '',
    nick: nick
   }));
   return ;
  }
  cout.write(`${chunk}\n\r`);
 });
 client.on('error', (err) => {
  cout.write(`an error has occured.\n\r${err}`);
 });
}
/**
 * 创建socket并连接服务器
 */
function createClient(){
 console.log('\033[2J');//清屏操作
 cout.write(`输入'EXIT OR QUIT'退出聊天室.\r\n`);
 client = new net.Socket()
 client.connect({port:8060/*,host:'1.1.1.69'*/});
 addListener(client);
}