var app = require('http').createServer(),
io = require('socket.io').listen(app),
fs = require('fs'),
mysql = require('mysql'),
connectionsArray = [],
profile_id,
last_count = 0, //this variable is to check previous count value
connection = mysql.createConnection({
host: 'localhost',
user: 'root',
password: '', //put your own mysql pwd
database: 'mrlerp2', //put your database name
port: 3306,
multipleStatements:true}), POLLING_INTERVAL = 2500,pollingTimer;

connection.connect(function(err) {
         console.log(err);
             });
  app.listen(8000);
             var pollingLoop = function(profile_id) {var sql="SELECT notify.notification_id,notify_mode.`mode`,notify_verb.verb,notify.msg,tab.name,notify.modifiedon FROM notification AS notify INNER JOIN notification_mode AS notify_mode ON notify_mode.notification_mode_id=notify.`mode` INNER JOIN notification_verb AS notify_verb ON notify_verb.notification_verb_id=notify.verb  inner join vtiger_tab as tab on tab.tabid=notify.module where notify.actor!='"+profile_id+"' and notify.userid='"+profile_id+"' ORDER BY modifiedon DESC;select count(*) as c from notification where is_read=1 and userid='"+profile_id+"' and actor!='"+profile_id+"'";
                            var query = connection.query(sql),
                            users = []; // this array will contain the result of our db query
            user_count=[];

                            query.on('error', function(err) {                                                                                                                                         // Handle error, and 'end' event will be emitted after this as well
                                             console.log(err);
                                 updateSockets(err,profile_id);
                                           })
                  .on('result', function(user) {                                                                                                                                                             // it fills our array looping on each user row inside the db
                    users.push(user);
                                    if(typeof user.c !=='undefined'){
                                        user_count.push(user.c);
                                    }
                    })
                .on('end',function(){                                                                                                                                                                     // loop on itself only if there are sockets still connected
                                                                                                                                                                                             if (connectionsArray.length) {

                        Object.keys(connectionsArray).forEach(function(v){
                                                                                                                                                                                                 pollingTimer = setTimeout(pollingLoop(v), POLLING_INTERVAL);

updateSockets(

                                            {users: users,
                                            count:user_count},
                                profile_id
                                );

                        });

                        }
                                                                                                                                                                                                            })
                                                                                                                                                                                                        };

profile_id = socket.handshake.query.profile_id;

         if(!connectionsArray.hasOwnProperty(profile_id)){
                                                                                                                 console.log('A new socket is connected!');
                            console.log(profile_id);                                                                             connectionsArray[profile_id]=socket;
                                                        }
                                                                              if (connectionsArray.length>0) {
                    Object.keys(connectionsArray).forEach(function(v){
                        if(typeof v !=='undefined'){
                          pollingLoop(v);
                            }
                            });
                                }
              socket.on('update_viewed_notify',function(){                                                                               connection.query("update notification set is_read=0");                                                                          });
      socket.on('destroy_socket',function(data){
               socket.on('disconnect', function() {
                   var socketIndex = connectionsArray.indexOf(socket);
                                 if (socketIndex >= 0) {
                                connectionsArray.splice(socketIndex, 1);
                           }
                                                                                                          });
                            });
             connectionsArray.push(socket);
       });
                                                                            var updateSockets = function(data,profile_id) {              connectionsArray[profile_id].emit('notification', data);                                                                                 };