//Define libraries
#include "WiFi.h";
#include "PubSubClient.h"
int led_pin = 5;
char clientId [50];
WiFiClient espClient;
PubSubClient client(espClient);

void setup() 
{
  Serial.begin(115200);
  pinMode(led_pin, OUTPUT);
  WiFi.mode(WIFI_STA);
  WiFi.begin("Wowki-GUEST","");
  client.setServer("broker.emqx.io",1883);
  client.setCallback(callback);

}


void mqttReconnect() 
{

  while (!client.connected()){
    Serial.print("Attempting MQTT Connection -------");
    if (client.connect(clientId)){
      Serial.println("connected");
      client.subscribe("LEDStatus");

    }
    else{
      Serial.print("Connection Failed, Try Again in 5 Seconds");
      delay(5000);
    }
  }
}

void callback(char* topic, byte* message, unsigned int length) 
{
  String stMessage;
  for (int i = 0; i < length; i++) 
  {
    stMessage += (char)message[i];
  }
  if (stMessage == "off"){
    digitalWrite(led_pin, LOW);
    Serial.print("Light OFF");
  }
  else if (stMessage == "on"){
    digitalWrite(led_pin, HIGH);
    Serial.print("Light ON");
  }else{
    Serial.print("Invalid Command");
  }
}

void loop() 
{
  delay(10000);
  if(!client.connected()){
    mqttReconnect();
  }
  client.loop();
}