Server

require('dotenv').config();

var app = require('express')();
var server = require('http').Server(app);
var io = require('socket.io')(server);
var mysql = require('mysql');
var Redis = require('ioredis');
var redisClient = Redis.createClient();

///////////////////////////         Mysql Connection        ////////////////////////////////
// var con = mysql.createConnection({
//      host: process.env.DB_HOST,
//      user: process.env.DB_USERNAME,
//      password: process.env.DB_PASSWORD,
//      database: process.env.DB_DATABASE
//  });

// con.connect(function(err) {
//   if (err) console.error.bind(console, 'DB Connection Error:');
//   else console.log("DB Connected!");
// });

var db_config = {
    host: process.env.DB_HOST,
    user: process.env.DB_USERNAME,
    password: process.env.DB_PASSWORD,
    database: process.env.DB_DATABASE
        };

var con;

function handleDisconnect() {

  con = mysql.createConnection(db_config); // Recreate the connection, since
                                                  // the old one cannot be reused.

  con.connect(function(err) {              // The server is either down
        if(err)
            {                                     // or restarting (takes a while sometimes).
                console.log('error when connecting to db:', err.message);
                setTimeout(handleDisconnect, 2000); // We introduce a delay before attempting to reconnect,
            }
        else
            {
                console.log("DB Connected!");
            }                                     // to avoid a hot loop, and to allow our node script to
  });                                     // process asynchronous requests in the meantime.

  con.on('error', function(err) {
        console.log('db error', err);
        if(err.code === 'PROTOCOL_CONNECTION_LOST')
            { // Connection to the MySQL server is usually
                handleDisconnect();                         // lost due to either server restart, or a
            }
        else
            {                                      // connnection idle timeout (the wait_timeout
                console.log("Mysql Error - ",err.message);
                throw err;                                  // server variable configures this)
            }
  });

}

handleDisconnect();

///////////////////////////         Mysql Connection        ////////////////////////////////

var port_number = process.env.SOCKET_IO_PORT || 8080;

server.listen(port_number, function(){
    console.log("Listening on localhost:"+port_number)
});

var clients = {};

///////////////////////////////////////         App Chat    //////////////////////////////////////////////////////////
    redisClient.subscribe('message');
    redisClient.on("message", function(channel, data) {

        var tempdata = JSON.parse(data)
        //console.log("Sending: " + data);

        if(clients[tempdata.receiver_id])
            {
                io.sockets.connected[clients[tempdata.receiver_id].socket].emit('new-message', tempdata);
            }
        else
            {
                console.log("User does not exist: " + JSON.stringify(tempdata));
            }

    });
///////////////////////////////////////         App Chat    //////////////////////////////////////////////////////////


io.on('connect', function (socket) {

/////////////////////////////////////////////////////
//////////////////          Add User Event      /////////////////////////////////
    socket.on('add-user', function(data)
        {
            //console.log('data - ',data);
            con.query(`SELECT * FROM users WHERE id = `+data.user_id+` AND blocked='0' AND access_token='`+data.access_token+`' LIMIT 0,1 `, function (error, results, fields)
                    {

                        if(error)
                            {
                                io.sockets.connected[data.socket_id].emit('add-user-auth', {success:0, msg: error.message});
                                console.log(error.message);
                            }
                        else
                            {

                                if(results.length != 0)
                                    {
                                        // console.log('New User Added - '+JSON.stringify(clients))
                                        clients[data.user_id] =
                                            {
                                                "socket": data.socket_id
                                            };

                                        io.sockets.connected[data.socket_id].emit('add-user-auth', {success:1, msg: 'Connected'});

                                        console.log('New User Added - '+results[0].id)

                                    }
                                else
                                    {
                                        io.sockets.connected[data.socket_id].emit('add-user-auth', {success:0, msg: 'Invalid Access token'});
                                        console.log('Wrong Access Token - '+data.user_id);
                                    }

                            }

                    });

        });
//////////////////          Add User Evendt         /////////////////////////////////
/////////////////////////////////////////////////////

  //Removing the socket on disconnect
    socket.on('disconnect', function()
        {

            for(var id in clients)
                {
                    if(clients[id].socket === socket.id)
                        {
                            delete clients[id];
                            break;
                        }
                }

            //console.log('Connection Disconnected', JSON.stringify(clients));
            //redisClient.quit();

        });


});