#define LDR_PIN A0
#define BUZZER_PIN 3

int baselineLight = 0;
bool alarmActive = false;

void setup() {
  pinMode(BUZZER_PIN, OUTPUT);
  digitalWrite(BUZZER_PIN, LOW);

  Serial.begin(9600);
  Serial.println("Laser Security Line Simulation");
  Serial.println("Calibrating...");

  // ===== КАЛИБРОВКА =====
  int sum = 0;
  for (int i = 0; i < 10; i++) {
    sum += analogRead(LDR_PIN);
    delay(100);
  }
  baselineLight = sum / 10;

  Serial.print("Baseline light level: ");
  Serial.println(baselineLight);
  Serial.println("System armed");
  Serial.println("Type RESET to disable alarm");
}

void loop() {
  // ===== ПРОВЕРКА СБРОСА =====
  if (Serial.available()) {
    String cmd = Serial.readStringUntil('\n');
    cmd.trim();
    if (cmd == "RESET") {
      alarmActive = false;
      noTone(BUZZER_PIN);
      Serial.println("Alarm RESET");
    }
  }

  int currentLight = analogRead(LDR_PIN);

  // ===== ОБНАРУЖЕНИЕ ПЕРЕСЕЧЕНИЯ =====
  if (currentLight < baselineLight - 100 && !alarmActive) {
    alarmActive = true;
    Serial.println("ALARM! Beam interrupted!");
  }

  // ===== СИРЕНА =====
  if (alarmActive) {
    tone(BUZZER_PIN, 1000);
  }

  delay(100);
}