server.js

//create server  hello
const express =  require("express");
const app = express();
const path = require("path");
const http = require("http");
const serv = http.Server(app); 
const morgan = require("morgan");
app.use(morgan('dev'));

const PORT = process.env.PORT || 3000;
serv.listen(PORT, function(){
    console.log("listening at "+PORT);
});

app.use(express.static(__dirname+"/public"));
app.get("/",function(req,res){
    res.sendFile('index.html', {root: __dirname});
});

// app.get("/game",function(req,res){
//     res.sendFile('game-page.html', {root: __dirname});
// });

if (process.env.NODE_ENV === 'production') {
    // Exprees will serve up production assets
    app.use(express.static('client/build'));
  
    // Express serve up index.html file if it doesn't recognize route
    const path = require('path');
    app.get('*', (req, res) => {
      res.sendFile(path.resolve(__dirname, 'client', 'build', 'index.html'));
    });
  }

app.use(express.json());
app.use(express.urlencoded());

const chatRouter = require('./routes/post');
app.use(chatRouter);

const createDB = require('./daos/db');
const { loginService } = require("./services/userServices");
createDB();

//player constructor
// const createDB = require('./daos/db');
// createDB();

//loading socket.io and binding to server
const io = require('socket.io')(serv);

var Player = function(name,id){
    self = {
    name: name,
    score : 0,
    id: id
    }
    return self;
}

//list of sockets
SOCKET_LIST = {};
//list of scores&players
SCORES_LIST = {};

io.sockets.on('connection', function(socket) {
    console.log(socket.id + 'has joined the game.');
    //create a player
    var player = new Player(name = 'anonymous', socket.id);
    
    //event thrown when user wants to play as guest
    socket.on('username-submit', function(username) {
        player.name = username;
        console.log("hello" + username); // for debugging
        io.emit('participant', '<i>' + player.name + ' joined the game...</i>');
    })

    SCORES_LIST[socket.id] = player;
    SOCKET_LIST[socket.id] = socket;
    
    //this event is thrown when user chooses to login
    socket.on('login', function(nameAndPwd){
        console.log(`login event!`);
        console.log("database time");
        player.name = nameAndPwd.name;
        loginService(player.name, nameAndPwd.pwd, null);
        io.emit('participant', '<i>' + player.name + ' joined the game...</i>');
        //we send the event 'participant' and a message including the pseudoname
    });
    
    //event thrown when user wants to register
    socket.on('register', function(nameAndPwd){
        console.log(`login event!`);
        console.log("database time");
        player.name = nameAndPwd.name;
        loginService(player.name, nameAndPwd.pwd, null);
        io.emit('participant', '<i>' + player.name + ' joined the game...</i>');
        //we send the event 'participant' and a message including the pseudoname
    });

    //listen for new score updates from user, then change player.score accordingly
    socket.on('sendNewScore', function(score) {
        player.score = score;
    });
   
    //chat feature
    socket.on('submitted_message', function(message) {
        io.emit('submitted_message', '<strong>' + player.name + ' : </strong>' + message);
        console.log(message);
    });

    socket.on('disconnect', function() {
        console.log(socket.id + 'has left the game.')
        delete SCORES_LIST[socket.id];
        delete SOCKET_LIST[socket.id];
        io.emit('participant', '<i>' + player.name + ' left the game...</i>');
    });
});

//emit score every 40 milliseconds
setInterval(function(){
    // info about name and scores of everyone to be sent to every player
    var pack = [];
    for(var i in SCORES_LIST){
        var score_player = SCORES_LIST[i];
        pack.push({
            name: score_player.name,
            score: score_player.score
        })
    }
        
    sortedPack = updateLeaderBoard(pack);
    
    for(var j in SOCKET_LIST){
        var socket = SOCKET_LIST[j];
        socket.emit('updateScores', sortedPack);
    }
},50);

function updateLeaderBoard(list) {
    let newList = [];
    list.sort(function(a, b){ return b.score - a.score });
    for(let i = 0; i<list.length; i++){
        newList[i] = (i+1) + " - " + list[i].name + " : " + list[i].score;
    }
    return newList;
}