// Solution of MQTTHandsOnNodeJSClient, part of http://tmb.gr/mqtt
// Licensed https://tamberg.mit-license.org/

// Terminal 1: $ node bot3.js 
// Terminal 2: $ mqtt pub -t 'chats/tamberg' -h 'test.mosquitto.org' -m '{"clientId":"tamberg", "message": "nice"}'

// Terminal 1: (Output)
// {"clientId":"tamberg", "message": "nice"}
// {"clientId":"mqttjs_8a925bfc", "message":"not nice"}

var mqtt = require('mqtt');
var client = mqtt.connect('mqtt://test.mosquitto.org/');

function toJson(clientId, message) {
  return '{"clientId":"' + clientId + '", "message":"' + message + '"}';
}

client.on('connect', function () {
  client.subscribe('chats/tamberg');
});

client.on('message', function (topic, message) {
  console.log(message.toString());
  var json = JSON.parse(message);
  var prefix = 'not ';
  var botClientId = client.options.clientId;
  if (botClientId != json.clientId) {
    client.publish('chats/tamberg',
      toJson(botClientId, prefix + json.message));
  }
});