#include <WiFi.h>
#include "PubSubClient.h"
// WiFi
char ssid[] = "Wokwi-GUEST";
char pass[] = "";
// MQTT BROKER
const char *mqtt_broker = "broker.emqx.io";
const char *mqtt_username = "emqx";
const char *mqtt_password = "public";
const int mqtt_port = 1883;
// App protocol
const char *topic_publish = "emqx/esp32/p";
const char *topic_subscribe = "emqx/esp32/s";
WiFiClient espClient;
PubSubClient client(espClient);
void callback(char *topic, byte *payload, unsigned int length);
#define LED 2
bool ledstate = false;

void setup(){
  pinMode(LED, OUTPUT);
  digitalWrite(LED, LOW);
  Serial.begin(115200);
  WiFi.begin(ssid,pass);
  Serial.print("Connecting");
  while (WiFi.status() != WL_CONNECTED){
    delay(500);
    Serial.print(".");
  }
  Serial.println("Connected!");
  Serial.println("Configuring MQTT Broker");
  client.setServer(mqtt_broker,mqtt_port);

  while(!client.connected()){
    String client_ID = "ESP32-client-";
    client_ID += String(WiFi.macAddress());
    Serial.println("Connecting to MQTT Broker with client ID = ");
    Serial.println(client_ID.c_str());
    if(client.connect(client_ID.c_str(),mqtt_username,mqtt_password)) {
      Serial.println("Connected to public MQTT!");
    }
    else {
      Serial.println("Failed to connect with state: ");
      Serial.println(client.state());
      delay(2000);
    }
  }
  client.publish(topic_publish,"ESP32 Hello World");
  client.subscribe(topic_subscribe);
  client.setCallback(callback);
}

void loop() {
  client.loop();
}

void callback(char *topic, byte *payload, unsigned int length) {
    Serial.print("Message arrived in topic: ");
    Serial.println(topic);
    Serial.print("Message:");
    String message;
    for (int i = 0; i < length; i++) {
       message += (char) payload[i];
    }
    Serial.println(message);
    if(message == "on"){
      digitalWrite(LED, HIGH);
    }
    if(message == "off"){
      digitalWrite(LED, LOW);
    }
    Serial.println("-----------------------");
}