#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",1883);
client.setCallback(callback);
}


void mqttReconnect() 
{
while (!client.connected()){
  Serial.print("Attempting MQTT Connection....");
  if (client.connect(ClientID)){
    Serial.print("Connected");
    client.subscribe("topicName");
  }
  else{
    Serial.println("Connection Failed. Trying 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();
}