#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.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.println("LIGHT OFF!!");
  }
  else if (stMessage == "on")
  {
    digitalWrite(led_pin, HIGH);
    Serial.println("LIGHT ON!!");
  }
  else
  {
    Serial.println("INVALID COMMAND!!");
  }
}

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