const int trigPin1 = 9;
const int echoPin1 = 10;

const int trigPin2 = 11;
const int echoPin2 = 12;

const int buzzerPin = 8;

const long distanceThreshold = 20; // cm

bool alertTriggered = false;

long measureDistance(int trigPin, int echoPin);

void setup() {
  Serial.begin(9600);

  pinMode(trigPin1, OUTPUT);
  pinMode(echoPin1, INPUT);

  pinMode(trigPin2, OUTPUT);
  pinMode(echoPin2, INPUT);

  pinMode(buzzerPin, OUTPUT);
  digitalWrite(buzzerPin, LOW);
}

void loop() {

  long distance1 = measureDistance(trigPin1, echoPin1);
  long distance2 = measureDistance(trigPin2, echoPin2);

  Serial.print("D1: ");
  Serial.print(distance1);
  Serial.print(" cm | D2: ");
  Serial.print(distance2);
  Serial.println(" cm");

  bool sensor1Active = (distance1 > 0 && distance1 <= distanceThreshold);
  bool sensor2Active = (distance2 > 0 && distance2 <= distanceThreshold);

  int beepCount = 0;

  // Karar mantığı
  if (sensor1Active && sensor2Active) {
    beepCount = 3;
  }
  else if (sensor1Active || sensor2Active) {
    beepCount = 2;
  }

  // SADECE BİR KEZ ÇAL
  if (beepCount > 0 && !alertTriggered) {
    for (int i = 0; i < beepCount; i++) {
      digitalWrite(buzzerPin, HIGH);
      delay(200);
      digitalWrite(buzzerPin, LOW);
      delay(200);
    }
    alertTriggered = true;
  }

  // Nesne çekilince sistemi sıfırla
  if (!sensor1Active && !sensor2Active) {
    alertTriggered = false;
  }

  delay(100);
}

long measureDistance(int trigPin, int echoPin) {

  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  long duration = pulseIn(echoPin, HIGH, 30000);

  if (duration == 0) {
    return -1;
  }

  return duration * 0.034 / 2;
}