#include <WiFi.h>
#include <PubSubClient.h>

#define GAS_SENSOR_PIN 34  // Pin analog untuk MQ-2
#define LED_PIN 2          // Indikator LED
#define THRESHOLD 2000     // Ambang bahaya gas

// Ganti sesuai WiFi kamu
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// Broker MQTT publik (bisa pakai lokal juga)
const char* mqtt_server = "test.mosquitto.org";

WiFiClient espClient;
PubSubClient client(espClient);

void setup_wifi() {
  delay(100);
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  Serial.print("Menghubungkan ke WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi Terhubung");
}

void reconnect() {
  while (!client.connected()) {
    Serial.print("Menghubungkan MQTT...");
    if (client.connect("ESP32Client")) {
      Serial.println("Terhubung!");
    } else {
      Serial.print("Gagal, rc=");
      Serial.println(client.state());
      delay(2000);
    }
  }
}

void setup() {
  pinMode(LED_PIN, OUTPUT);
  setup_wifi();
  client.setServer(mqtt_server, 1883);
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  int gasValue = analogRead(GAS_SENSOR_PIN);
  Serial.print("Gas value: ");
  Serial.println(gasValue);

  if (gasValue > THRESHOLD) {
    digitalWrite(LED_PIN, HIGH);
  } else {
    digitalWrite(LED_PIN, LOW);
  }

  // Kirim data ke topik "esp32/gas"
  String payload = String(gasValue);
  client.publish("esp32/gas", payload.c_str());

  delay(1000);
}