var Command  = require('./command');
var util    = require('util');
var CommandCode = require('../constants/commands');
var Packet = require('../packets/packet');

// TODO: time statistics?
// usefull for queue size and network latency monitoring
// store created,sent,reply timestamps

function Ping(callback)
{
  Command.call(this);
  this.onResult = callback;
}
util.inherits(Ping, Command);

Ping.prototype.start = function(packet, connection) {
  var ping = new Packet(0, new Buffer([0, 0, 0, 0, CommandCode.PING]));
  connection.writePacket(ping);
  return Ping.prototype.pingResponse;
};

Ping.prototype.pingResponse = function(packet) {
  // TODO: check it's OK packet. error check already done in caller
  if (this.onResult)
    process.nextTick(this.onResult.bind(this));
  return null;
};

module.exports = Ping;