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

#define BUZZER_PIN 15
#define MQTT_SERVER "broker.hivemq.com"
#define MQTT_PORT 1883
#define TOPIC "distance"

const char* ssid = "Wokwi-GUEST";
const char* password = "";

WiFiClient espClient;
PubSubClient client(espClient);

void setup() {
  Serial.begin(115200);
  pinMode(BUZZER_PIN, OUTPUT);
  
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
  }
  
  client.setServer(MQTT_SERVER, MQTT_PORT);
  client.setCallback(callback);
}

void reconnect() {
  while (!client.connected()) {
    if (client.connect("ESP32Subscriber")) {
      client.subscribe(TOPIC);
    } else {
      delay(5000);
    }
  }
}

void callback(char* topic, byte* payload, unsigned int length) {
  char message[length + 1];
  strncpy(message, (char*)payload, length);
  message[length] = '\0';

  float distance = atof(message);
  if (distance < 100) {
    digitalWrite(BUZZER_PIN, HIGH);
    tone(BUZZER_PIN,2000);
    Serial.println("Alerte ! Obstacle détecté.");
    delay(1000);
    digitalWrite(BUZZER_PIN, LOW);
    noTone(BUZZER_PIN);
  }
}

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