// ESP32 + MQ2: publishes the analog value to the IMITECH MQTT broker once per second.
// Wiring: MQ2 VCC -> 5V (VIN), GND -> GND, AOUT -> GPIO34.
// The MQ2 outputs up to 5 V on AOUT; put a voltage divider (e.g. 10k + 20k) in front of the ESP32 pin.
// Library: "PubSubClient" (Arduino Library Manager).
#include <WiFi.h>
#include <WiFiClientSecure.h>
#include <PubSubClient.h>

const char* WIFI_SSID = "YOUR_WIFI";
const char* WIFI_PASS = "YOUR_PASSWORD";
const char* MQTT_HOST = "monitoringiotkit.imitech.my.id";
const int MQTT_PORT = 8883;                       // TLS
const char* MQTT_USER = "aeronix-mq2-001";
const char* MQTT_PASS = "YOUR_MQTT_PASSWORD";     // ask the site owner
const char* TOPIC = "aeronix/v1/mq2-001/telemetry";
const int MQ2_PIN = 34;

WiFiClientSecure net;
PubSubClient mqtt(net);

void connectMqtt() {
  while (!mqtt.connected()) {
    if (!mqtt.connect("aeronix-mq2-001", MQTT_USER, MQTT_PASS)) delay(2000);
  }
}

void setup() {
  Serial.begin(115200);
  analogReadResolution(12);                       // values 0..4095
  WiFi.begin(WIFI_SSID, WIFI_PASS);
  while (WiFi.status() != WL_CONNECTED) delay(300);
  net.setInsecure();                              // no certificate check; add the CA for a stricter setup
  mqtt.setServer(MQTT_HOST, MQTT_PORT);
}

void loop() {
  if (!mqtt.connected()) connectMqtt();
  mqtt.loop();

  long sum = 0;
  for (int i = 0; i < 16; i++) sum += analogRead(MQ2_PIN);   // average out the noise
  int value = sum / 16;

  String body = "{\"value\":" + String(value) + "}";
  bool ok = mqtt.publish(TOPIC, body.c_str());
  Serial.printf("value=%d published=%d\n", value, ok);
  delay(1000);
}