#include <PubSubClient.h>
#include "WiFi.h"
byte ledpin=12;
const char* mqttServer = "broker.hivemq.com";
int port = 1883;
char clientId[50];
const char* ssid = "Wokwi-GUEST";
int channel = 6;
const char* password = "";
WiFiClient espClient;
PubSubClient client(espClient);
void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  Serial.print("Connecting to ");
  Serial.println(ssid);
  wifiConnect();
  pinMode(ledpin, OUTPUT);
  client.setServer(mqttServer, port);
  client.setCallback(callback);
}
void loop() {
  // put your main code here, to run repeatedly:
  if (!client.connected())
  {
    mqttReconnect();
  }
 /* else
  {
    client.publish("esp32", "data got");

  }*/
  client.loop();
}
void wifiConnect() {
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
}
void mqttReconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    long r = random(1000);
    sprintf(clientId, "fcs-clientId-%ld", r);
    if (client.connect(clientId)) {
      Serial.print(clientId);
      Serial.println("connected");
      client.subscribe("esp32-h");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}
void callback(char* topic ,byte* message,unsigned int length)
{
  Serial.print("Message arrived in topic");
  Serial.print(topic);
  Serial.print("Message:");
  String stMessage;

  for (int i=0;i<length;i++)
  {
    Serial.print((char)message[i]);
    stMessage+=(char)message[i];
  }
  if(stMessage=="ON")
  {
    digitalWrite(ledpin, HIGH);
  }
  else if(stMessage=="OFF")
  {
    digitalWrite(ledpin, LOW);
  }
  
}