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

const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "broker.hivemq.com";

WiFiClient espClient;
PubSubClient client(espClient);

#define mq2Pin 34
#define buzzerPin 25
#define ledPin 26

int gasThreshold = 2000;

void setup_wifi() {
  delay(10);
  Serial.println();
  Serial.print("Подключение к ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("\nWiFi подключен");
}

void reconnect() {
  while (!client.connected()) {
    Serial.print("Подключение к MQTT...");
    
    if (client.connect("ESP32Client123")) {
      Serial.println("успешно");
    } else {
      Serial.print("ошибка rc=");
      Serial.print(client.state());
      Serial.println(" повтор через 2 секунды");
      delay(2000);
    }
  }
}

void setup() {
  Serial.begin(115200);

  pinMode(buzzerPin, OUTPUT);
  pinMode(ledPin, OUTPUT);

  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setKeepAlive(60);
}

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

  int value = analogRead(mq2Pin);

  Serial.print("Газ: ");
  Serial.println(value);

  char msg[50];

  if (value > gasThreshold) {
    digitalWrite(ledPin, HIGH);
    tone(buzzerPin, 1000);
    strcpy(msg, "ТРЕВОГА: обнаружен газ");
    client.publish("wokwi/mq2_alert", msg);
  } else {
    digitalWrite(ledPin, LOW);
    noTone(buzzerPin);
    strcpy(msg, "НОРМА");
    client.publish("wokwi/mq2_alert", msg);
  }

  delay(2000);
}