app.js

const express = require('express');
const app = express();
const server = require('http').createServer(app);
const io = require('socket.io').listen(server);
const bodyParser = require('body-parser');
const Ball = require('./libs/ball');
const User = require('./libs/user');

const PORT = process.env.PORT || 3000;

let canvasWidth = 800; // Make sure to be same as on client's
let canvasHeight = 600; // Make sure to be same as on client's
let fieldOffset = 30; // Make sure to be same as on client's
let userR = 20; // Make sure to be same as on client's
let goal = {
    x: fieldOffset,
    y: 150 // Make sure to be same as on client's goalSize
}


let connections = [];
let users = [];
let ball = new Ball(canvasWidth, canvasHeight);
let teams = [{
    name: 'Pink',
    count: 0,
    score: 0
},{
    name: 'Teal',
    count: 0,
    score: 0
}];

setInterval(tick, 33); // 1000 / x = frames / second
//setInterval(()=>{console.log(users); console.log();}, 2000);
function tick() {
//    console.log(users);
//    console.log('------------------------------');
    io.sockets.emit('tick', {users: users, ballLoc: ball.location});
    
    checkBallCollision(users, ball);
    ballEdges(ball);
    ball.update();
//    console.log(ball);
}



app.use(express.static(__dirname + '/public'));
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());

app.get('/', (req, res) => {
    res.send('index.html');
});

server.listen(PORT, () => {
    console.log("Server listening on port", PORT);
});

io.sockets.on('connection', (socket) => {
    connections.push(socket);
    console.log('Connected: %s sockets connected.', connections.length);
    
    socket.emit('connectNewUser', createNewUser(socket.id));
    
    socket.on('updateUser', (updatedUser) => {
        users.forEach(user => {
            if(user.id === socket.id){
                user.x = updatedUser.x;
                user.y = updatedUser.y;
                user.isKicking = updatedUser.isKicking;
            }
        })
    });
    
    socket.on('setName', newName => {
        users.forEach(user => {
            if(user.id === socket.id){
                user.name = newName;
            }
        });
    });
    
    //Disconnect
    socket.on('disconnect', (data) => {
        connections.splice(connections.indexOf(socket), 1);
        users = users.filter(user => user.id !== socket.id);
        console.log('Disconnected: %s sockets connected.', connections.length);
    });
});

function createNewUser(_id) {
    let newUser = {};
    
    newUser.id = _id;
    newUser.team = getTeam();
    newUser.name = 'Unnamed';
    
    if(newUser.team === teams[0].name){ // Pink
        newUser.x = (Math.random() * (canvasWidth / 2 - userR)) + fieldOffset + userR;
    } else { // Teal
        newUser.x = (Math.random() * (canvasWidth / 2 - fieldOffset - userR)) + (canvasWidth / 2) + userR;
    }
    
    newUser.y = (Math.random() * (canvasHeight - userR / 2)) + userR;
    
    users.push(newUser);
    return newUser;
}

function getTeam() {
    let teamName;
    
    // If teal team has more users, add to pink
    if(teams[1].count > teams[0].count){
        teamName = teams[0].name;
        teams[0].count++;
    } else {
        teamName = teams[1].name;
        teams[1].count++;
    }
    
    return teamName;
}

function scored(team) {
    if(team === teams[0].name)      // purple scorred
        teams[0].score++;
    else if(team === teams[1].name) // teal scorred
        teams[1].score++;
    
    if(teams[0].score === 5 || teams[1].score === 5){ // End of one round / Reset score
        teams[0].score = 0;
        teams[1].score = 0;
    }
    
    let scores = {
        pink: teams[0].score,
        teal: teams[1].score
    }
    io.sockets.emit('scored', scores)
    
    ball.stopBall();
    ball.location.x = canvasWidth / 2 ;
    ball.location.y = canvasHeight / 2;
}

function mag(vector) {
    return Math.sqrt(vector.x * vector.x + vector.y * vector.y);
}

function normalize(vector) {
    var m = mag(vector);
    if(m > 0){
        vector.x /= m;
        vector.y /= m;
    }
    return vector;
}

function setMag(vector, val) {
    vector = normalize(vector);
    vector.x *= val;
    vector.y *= val;
    
    return vector;
}

function dist(x1, y1, x2, y2) {
    return Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2));
}

function checkBallCollision(users, ball) {
    
    users.forEach(user => {
        let d = dist(user.x, user.y, ball.location.x, ball.location.y);
        let pushForce;
        
        if(d <= userR + ball.r){
            pushForce = {
                x: ball.location.x - user.x,
                y: ball.location.y - user.y
            };
            if(user.isKicking) {
                pushForce = setMag(pushForce, 20);
            } else {
                pushForce = setMag(pushForce, 1.5);
                user.isKicking = false;
            }
            ball.applyForce(pushForce);
        }
    });
}

function ballEdges(ball) {
    
    // Check if outside the goal (y check) right-side
    if(ball.location.x + ball.r > canvasWidth - fieldOffset && ball.location.y < canvasHeight/2 - goal.y/2 || ball.location.x + ball.r > canvasWidth - fieldOffset && ball.location.y > canvasHeight/2 + goal.y/2){
            ball.location.x = canvasWidth - ball.r - fieldOffset;
            ball.velocity.x *= -1;

    // Check if inside the goal right-side && score team 1 (pink)
    } else if (ball.location.x + ball.r > canvasWidth && ball.location.y > canvasHeight/2 - goal.y/2 || ball.location.x + ball.r > canvasWidth && ball.location.y < canvasHeight/2 + goal.y/2){
            ball.location.x = canvasWidth - ball.r;
            scored('Pink');            

    // Check if outside the goal (y check) left-side
    } else if (ball.location.x - ball.r < fieldOffset && ball.location.y < canvasHeight/2 - goal.y/2 || ball.location.x - ball.r < fieldOffset && ball.location.y > canvasHeight/2 + goal.y/2){
            ball.location.x = fieldOffset + ball.r;
            ball.velocity.x *= -1;

    // Check if inside the goal left-side && score team 1 (pink)
    } else if (ball.location.x - ball.r < 0 && ball.location.y > canvasHeight/2 - goal.y/2 || ball.location.x - ball.r < 0 && ball.location.y < canvasHeight/2 + goal.y/2){
            ball.location.x = ball.r;
            scored('Teal');
    }

    if(ball.location.y + ball.r > canvasHeight){
        ball.velocity.y *= -1;canvasHeight
        ball.location.y = canvasHeight - ball.r;
    } else if (ball.location.y - ball.r < 0) {
        ball.velocity.y *= -1;
        ball.location.y = ball.r;
    }
}