// Create an ESP8266 WiFiClient class to connect to the MQTT server.
WiFiClient client;
Adafruit_MQTT_Client *mqtt;
Adafruit_MQTT_Publish *mqtt_temp;

const char TEMPERATURE_FEED[] = "/feeds/temperature";

boolean mqttIsConfigured;

int publishMQTT(int temp) {
  if (MQTT_connect() == 0) {
    Serial.println("publishing !");
    mqtt_temp->publish(temp);
  }
}

int setupMQTT(char *server, char *user, char *passwd) {

  if(server == ""){
    Serial.println("Mqtt Server not configured");
  }
  // Setup the MQTT client class by passing in the WiFi client and MQTT server and login details.
  mqtt = new Adafruit_MQTT_Client(&client, server, 1883, user, passwd);
  mqtt_temp =  new Adafruit_MQTT_Publish(mqtt, TEMPERATURE_FEED);

  return 0;
}

// Function to connect and reconnect as necessary to the MQTT server.
// Should be called in the loop function and it will take care if connecting.
int MQTT_connect() {
  int8_t ret;

  // Stop if already connected.
  if (mqtt->connected()) {
    return 0;
  }

  uint8_t retries = 3;
  while ((ret = mqtt->connect()) != 0) { // connect will return 0 for connected
    Serial.println(mqtt->connectErrorString(ret));
    Serial.println("Retrying MQTT connection ...");
    mqtt->disconnect();
    delay(100);  // wait
    retries--;
    if (retries == 0) {
      return -1;
    }
  }
  return 0;
}