//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("wokwi-guest","");
client.setServer("broker.emqx.io",8083);
client.setCallback(callback);
}


void mqttReconnect(){
  while(!client.connected()){
    Serial.print("Attempting Mqtt connection");
    if(client.connect(clientId)){
      Serial.println("Connected");
      client.subscribe("TopicName");
    }
    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();
}