Some improvements + simplify TODOs

[xogo.git] / server.js

const params = require("./parameters.js");
const WebSocket = require("ws");
const wss = new WebSocket.Server(
  {port: params.socket_port, path: params.socket_path});

let challenges = {}; //variantName --> socketId, name
let games = {}; //gameId --> gameInfo (vname, fen, players, options, time)
let sockets = {}; //socketId --> socket
const variants = require("./variants.js");
const Crypto = require("crypto");
const randstrSize = 8;

function send(sid, code, data) {
  const socket = sockets[sid];
  // If a player deletes local infos and then tries to resume a game,
  // sockets[oppSid] will probably not exist anymore:
  if (socket) socket.send(JSON.stringify(Object.assign({ code: code }, data)));
}

function launchGame(vname, players, options) {
  const gid =
    Crypto.randomBytes(randstrSize).toString("hex").slice(0, randstrSize);
  games[gid] = {
    vname: vname,
    players: players,
    options: options,
    time: Date.now()
  };
  if (players.every(p => p)) {
    const gameInfo = Object.assign(
      // Provide seed so that both players initialize with same FEN
      {seed: Math.floor(Math.random() * 1984), gid: gid},
      games[gid]);
    for (const p of players) {
      send(p.sid,
           "gamestart",
           Object.assign({randvar: p.randvar}, gameInfo));
    }
  }
  else {
    // Incomplete players array: do not start game yet
    send(sid, "gamecreated", {gid: gid});
    // If nobody joins within 5 minutes, delete game
    setTimeout(
      () => {
        if (games[gid] && games[gid].players.some(p => !p))
          delete games[gid];
      },
      5 * 60000
    );
  }
}

function getRandomVariant() {
  // Pick a variant at random in the list
  const index = Math.floor(Math.random() * variants.length);
  return variants[index].name;
}

wss.on("connection", (socket, req) => {
  const sid = req.url.split("=")[1]; //...?sid=...
  sockets[sid] = socket;
  socket.isAlive = true;
  socket.on("pong", () => socket.isAlive = true);

  socket.on("message", (msg) => {
    const obj = JSON.parse(msg);
    switch (obj.code) {
      // Send challenge (may trigger game creation)
      case "seekgame": {
        let opponent = undefined,
            choice = undefined;
        const vname = obj.vname,
              randvar = (obj.vname == "_random");
        if (vname == "_random") {
          // Pick any current challenge if possible
          const currentChalls = Object.keys(challenges);
          if (currentChalls.length >= 1) {
            choice =
              currentChalls[Math.floor(Math.random() * currentChalls.length)];
            opponent = challenges[choice];
          }
        }
        else if (challenges[vname]) {
          opponent = challenges[vname];
          choice = vname;
        }
        if (opponent) {
          delete challenges[choice];
          if (choice == "_random") choice = getRandomVariant();
          // Launch game
          let players = [
            {sid: sid, name: obj.name, randvar: randvar},
            opponent
          ];
          if (Math.random() < 0.5) players = players.reverse();
          launchGame(choice, players, {}); //empty options => default
        }
        else
          // Place challenge and wait. 'randvar' indicate if we play anything
          challenges[vname] = {sid: sid, name: obj.name, randvar: randvar};
        break;
      }
      // Set FEN after game was created (received twice)
      case "setfen":
        games[obj.gid].fen = obj.fen;
        break;
      // Send back game informations
      case "getgame": {
        if (!games[obj.gid]) send(sid, "nogame");
        else send(sid, "gameinfo", games[obj.gid]);
        break;
      }
      // Cancel challenge
      case "cancelseek":
        delete challenges[obj.vname];
        break;
      // Receive rematch
      case "rematch":
        if (!games[obj.gid]) send(sid, "closerematch");
        else {
          const myIndex = (games[obj.gid].players[0].sid == sid ? 0 : 1);
          if (!games[obj.gid].rematch) games[obj.gid].rematch = [0, 0];
          games[obj.gid].rematch[myIndex] = !obj.random ? 1 : 2;
          if (games[obj.gid].rematch[1-myIndex]) {
            // Launch new game, colors reversed
            let vname = games[obj.gid].vname;
            const allrand = games[obj.gid].rematch.every(r => r == 2);
            if (allrand) vname = getRandomVariant();
            games[obj.gid].players.forEach(p =>
              p.randvar = allrand ? true : false);
            launchGame(vname,
                       games[obj.gid].players.reverse(),
                       games[obj.gid].options);
          }
        }
        break;
      // Rematch cancellation
      case "norematch":
        if (games[obj.gid]) {
          const myIndex = (games[obj.gid].players[0].sid == sid ? 0 : 1);
          send(games[obj.gid].players[1-myIndex].sid, "closerematch");
        }
        break;
      // Create game vs. friend
      case "creategame": {
        let players = [
          {sid: obj.player.sid, name: obj.player.name},
          undefined
        ];
        if (
          obj.player.color == 'b' ||
          (obj.player.color == '' && Math.random() < 0.5)
        ) {
          players = players.reverse();
        }
        launchGame(obj.vname, players, obj.options);
        break;
      }
      // Join game vs. friend
      case "joingame":
        if (!games[obj.gid]) send(sid, "jointoolate");
        else {
          // Join a game (started by some other player)
          const emptySlot = games[obj.gid].players.findIndex(p => !p);
          if (emptySlot < 0) send(sid, "jointoolate");
          games[obj.gid].players[emptySlot] = {sid: sid, name: obj.name};
          const gameInfo = Object.assign(
            // Provide seed so that both players initialize with same FEN
            {seed: Math.floor(Math.random()*1984), gid: obj.gid},
            games[obj.gid]);
          for (const p of games[obj.gid].players)
            send(p.sid, "gamestart", gameInfo);
        }
        break;
      // Relay a move + update games object
      case "newmove":
        games[obj.gid].fen = obj.fen;
        games[obj.gid].time = Date.now(); //update timestamp in case of
        const playingWhite = (games[obj.gid].players[0].sid == sid);
        const oppSid = games[obj.gid].players[playingWhite ? 1 : 0].sid;
        send(oppSid, "newmove", {moves: obj.moves});
        break;
      // Relay "game ends" message
      case "gameover":
        if (obj.relay) {
          const playingWhite = (games[obj.gid].players[0].sid == sid);
          const oppSid = games[obj.gid].players[playingWhite ? 1 : 0].sid;
          send(oppSid, "gameover", { gid: obj.gid });
        }
        // 2 minutes timeout for rematch:
        setTimeout(() => delete games[obj.gid], 2 * 60000);
        break;
    }
  });
  socket.on("close", () => {
    delete sockets[sid];
    for (const [key, value] of Object.entries(challenges)) {
      if (value.sid == sid) {
        delete challenges[key];
        break; //only one challenge per player
      }
    }
    for (let g of Object.values(games)) {
      const myIndex = g.players.findIndex(p => p.sid == sid);
      if (myIndex >= 0) {
        if (g.rematch && g.rematch[myIndex] > 0) g.rematch[myIndex] = 0;
        break; //only one game per player
      }
    }
  });
});

const heartbeat = setInterval(() => {
  wss.clients.forEach((ws) => {
    if (ws.isAlive === false) return ws.terminate();
    ws.isAlive = false;
    ws.ping();
  });
}, 30000);

// Every 24 hours, scan games and remove if last move older than 24h
const dayInMillisecs = 24 * 60 * 60 * 1000;
const killOldGames = setInterval(() => {
  const now = Date.now();
  Object.keys(games).forEach(gid => {
    if (now - games[gid].time >= dayInMillisecs) delete games[gid];
  });
}, dayInMillisecs);

// TODO: useful code here?
wss.on("close", () => {
  clearInterval(heartbeat);
  clearInterval(killOldGames);
});