var express = require('express');
var app = express();
var server = require('http').Server(app);
var io = require('socket.io')(server);

// 存放在线用户k-编号v-socket
var socketMap = {};
// 自增编号
var number = 0;

// 昵称数组
var uname_list = [];

server.listen(5001);

app.use(express.static('public'));

io.on('connection', function (socket) {
  // 获取用户名后发出waiting
  socket.on('uname', function(uname) {
    console.log("[connect] number = %d",number);
    number ++;
    socket.clientNum = number;
    socketMap[number] = socket;
    console.log("server got uname = %s, id = %d", uname, number);
    if (number % 2 === 1) {
      uname_list[number] = uname;
      socket.emit('waiting', number);
    } else {
      uname_list[number] = uname;
      if (socketMap[number - 1]) {
        // 指明玩家单双号，发送对手用户名
        socketMap[number - 1].emit("first", uname_list[number]);
        socket.emit("second", uname_list[number - 1]);
      } else {
        socket.emit("leave");
      }
    }
  });

  socket.on('go', function (i, j, isWin) {
    socketMap[getMatch(socket.clientNum)].emit("go", i, j);
    if (isWin) {
      socketMap[getMatch(socket.clientNum)].emit("fail");
    }
  });
  socket.on("disconnect", function () {
    delete(socketMap[socket.clientNum]);
    console.log('User ['+ uname_list[socket.clientNum] + "] leave.");
    if (socket.clientNum % 2 !== 0 && number === socket.clientNum && !socketMap[getMatch(socket.clientNum)]) {
      // 如果1和2进入，2走了，那么1走的时候符合该条件，num++后为奇数，下次进入的人就是4，是孤儿
      // 如果1 2 3 4 5, 2走了，1走的时候number不应该递增，否则5就是孤儿
      number = ((number+1)/2)*2; //对齐至偶数便于下次的配对
    }
    if (socketMap[getMatch(socket.clientNum)]) {
      socketMap[getMatch(socket.clientNum)].emit('leave');
      delete(socketMap[getMatch(socket.clientNum)]);
    }
  });
});


// 从1开始，奇数匹配加一的数，偶数匹配减一的数
function getMatch(num) {
  if (num % 2 === 1) {
    return num + 1;
  } else {
    return num - 1;
  }
}