Experimental multi-tabs support (TODO: prevent multi-connect)

[vchess.git] / server / sockets.js

const url = require('url');

// Node version in Ubuntu 16.04 does not know about URL class
// NOTE: url is already transformed, without ?xxx=yyy... parts
function getJsonFromUrl(url)
{
  const query = url.substr(2); //starts with "/?"
  let result = {};
  query.split("&").forEach((part) => {
    const item = part.split("=");
    result[item[0]] = decodeURIComponent(item[1]);
  });
  return result;
}

module.exports = function(wss) {
  // Associative array page --> sid --> tmpId --> socket
  // "page" is either "/" for hall or "/game/some_gid" for Game,
  // tmpId is required if a same user (browser) has different tabs
  let clients = {};
  wss.on("connection", (socket, req) => {
    const query = getJsonFromUrl(req.url);
    const sid = query["sid"];
    const tmpId = query["tmpId"];
    const page = query["page"];
    const notifyRoom = (page,code,obj={}) => {
      Object.keys(clients[page]).forEach(k => {
        Object.keys(clients[page][k]).forEach(x => {
          if (k == sid && x == tmpId)
            return;
          clients[page][k][x].send(JSON.stringify(Object.assign(
            {code:code, from:sid}, obj)));
        });
      });
    };
    const deleteConnexion = () => {
      if (!clients[page] || !clients[page][sid] || !clients[page][sid][tmpId])
        return; //job already done
      delete clients[page][sid][tmpId];
      if (Object.keys(clients[page][sid]).length == 0)
      {
        delete clients[page][sid];
        if (Object.keys(clients[page]) == 0)
          delete clients[page];
      }
    };
    const messageListener = (objtxt) => {
      let obj = JSON.parse(objtxt);
      if (!!obj.target)
      {
        // Check if receiver is connected, because there may be some lag
        // between a client disconnects and another notice.
        if (Array.isArray(obj.target))
        {
          if (!clients[page][obj.target[0]] ||
            !clients[page][obj.target[0]][obj.target[1]])
          {
            return;
          }
        }
        else if (!clients[page][obj.target])
          return;
      }
      switch (obj.code)
      {
        // Wait for "connect" message to notify connection to the room,
        // because if game loading is slow the message listener might
        // not be ready too early.
        case "connect":
        {
          notifyRoom(page, "connect");
          if (page.indexOf("/game/") >= 0)
            notifyRoom("/", "gconnect", {page:page});
          break;
        }
        case "disconnect":
          // When page changes:
          deleteConnexion();
          if (!clients[page][sid])
          {
            // I effectively disconnected from this page:
            notifyRoom(page, "disconnect");
            if (page.indexOf("/game/") >= 0)
              notifyRoom("/", "gdisconnect", {page:page});
          }
          break;
        case "pollclients": //from Hall or Game
        {
          let sockIds = [];
          Object.keys(clients[page]).forEach(k => {
            // Poll myself if I'm on at least another tab (same page)
            if (k != sid || Object.keys(clients["/"][k]).length >= 2)
              sockIds.push(k);
          });
          socket.send(JSON.stringify({code:"pollclients", sockIds:sockIds}));
          break;
        }
        case "pollclientsandgamers": //from Hall
        {
          let sockIds = [];
          Object.keys(clients["/"]).forEach(k => {
            // Poll myself if I'm on at least another tab (same page)
            if (k != sid || Object.keys(clients["/"][k]).length >= 2)
              sockIds.push({sid:k});
          });
          // NOTE: a "gamer" could also just be an observer
          Object.keys(clients).forEach(p => {
            if (p != "/")
            {
              Object.keys(clients[p]).forEach(k => {
                if (k != sid)
                  sockIds.push({sid:k, page:p}); //page needed for gamers
              });
            }
          });
          socket.send(JSON.stringify({code:"pollclientsandgamers", sockIds:sockIds}));
          break;
        }

        // Asking something: from is fully identified,
        // but the requested resource can be from any tmpId (except current!)
        case "askidentity":
        case "asklastate":
        case "askchallenge":
        case "askgame":
        case "askfullgame":
        {
          const tmpIds = Object.keys(clients[page][obj.target]);
          if (obj.target == sid) //targetting myself
          {
            const idx_myTmpid = tmpIds.findIndex(x => x == tmpId);
            if (idx_myTmpid >= 0)
              tmpIds.splice(idx_myTmpid, 1);
          }
          const tmpId_idx = Math.floor(Math.random() * tmpIds.length);
          clients[page][obj.target][tmpIds[tmpId_idx]].send(
            JSON.stringify({code:obj.code, from:[sid,tmpId]}));
          break;
        }

        // Some Hall events: target all tmpId's (except mine),
        case "refusechallenge":
        case "startgame":
          Object.keys(clients[page][obj.target]).forEach(x => {
            if (obj.target != sid || x != tmpId)
            {
              clients[page][obj.target][x].send(JSON.stringify(
                {code:obj.code, data:obj.data}));
            }
          });
          break;

        // Notify all room: mostly game events
        case "newchat":
        case "newchallenge":
        case "newgame":
        case "deletechallenge":
        case "newmove":
        case "resign":
        case "abort":
        case "drawoffer":
        case "draw":
          notifyRoom(page, obj.code, {data:obj.data});
          break;

        // Passing, relaying something: from isn't needed,
        // but target is fully identified (sid + tmpId)
        case "challenge":
        case "fullgame":
        case "game":
        case "identity":
        case "lastate":
          clients[page][obj.target[0]][obj.target[1]].send(JSON.stringify(
            {code:obj.code, data:obj.data}));
          break;
      }
    };
    const closeListener = () => {
      // For tab or browser closing:
      deleteConnexion();
    };
    // Update clients object: add new connexion
    if (!clients[page])
      clients[page] = {[sid]: {[tmpId]: socket}};
    else if (!clients[page][sid])
      clients[page][sid] = {[tmpId]: socket};
    else
      clients[page][sid][tmpId] = socket;
    socket.on("message", messageListener);
    socket.on("close", closeListener);
  });
}