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 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)
});

///////////////////////////////////////         App Chat    //////////////////////////////////////////////////////////

 var redisClient = Redis.createClient();
 redisClient.subscribe('message');

redisClient.on("message", function(channel, data) {

    var tempdata = JSON.parse(data);
    var ids = JSON.parse(tempdata.socket_ids)

    console.log("New Message in queue "+ typeof ids, ', ', ids);

    ids.forEach(function(id){

        io.sockets.connected[id].emit('message', tempdata);

    });

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

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

/////////////////////////////////////////////////////
//////////////////          Add User Event      /////////////////////////////////
    socket.on('add-user', function(data)
        {

            if(!data.user_id)
                console.log('User Id is Required');
            else if(!data.api_token)
                console.log('User Api Token is Required');
            else
                {
//                              console.log(data);

                    var user = con.query("SELECT * FROM user_devices WHERE user_id= '"+data.user_id+"' AND api_token='"+data.api_token+"' ", function(error, results, fields){

                    if(error)
                        {
                            console.log(error.message);
                        }
                    else if(results == undefined || results.length == 0)
                        {
                            console.log("No Device Token Found");
                        }
                    else
                        {//////////////     Update user     //////////////////////

                            var update_device = con.query("UPDATE user_devices SET socket_id='"+data.socket_id+"' WHERE id="+results[0].id+" ", function(ierror, iresults, ifields){

                                    if(ierror)
                                        {
                                            console.log(ierror.message);
                                        }
                                    else
                                        {
                                            console.log("Socket ID Connected Successfully");
                                        }

//                              console.log(results, iresults, ifields);

                            });

                        }//////////////     Update user     //////////////////////


                    });

                }

        });
//////////////////          Add User Event      /////////////////////////////////
/////////////////////////////////////////////////////

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

            var update_device = con.query("UPDATE user_devices SET socket_id='' WHERE socket_id='"+socket.id+"' ", function(ierror, iresults, ifields)
                    {
                        if(ierror)
                            {
                                console.log(ierror.message);
                            }
                        else
                            {
                                console.log("Socket Disconnected Successfully");
                            }
//                              console.log(results, iresults, ifields);

                    });

        });

});