// Pin definitions
const int sensorIRPin = 12;     // Sensor IR
const int startButtonPin = 11;  // Tombol mulai
const int stopButtonPin = 10;   // Tombol stop
const int led1Pin = 2;        // LED1
const int led2Pin = 3;        // LED2
const int buzzerPin = 4;      // Buzzer

// Variables
bool isSystemActive = false;    // Status sistem aktif/tidak
bool isSensorTriggered = false;  // Status sensor IR
unsigned long lastSensorTrigger = 0;  // Waktu terakhir sensor terdeteksi
unsigned long buzzerStartTime = 0;   // Waktu buzzer mulai
bool isBuzzerActive = false;    // Status buzzer

void setup() {
  // Initialize button pins - sensorIR as INPUT (active HIGH), others with pull-up
  pinMode(sensorIRPin, INPUT);  // Sensor IR active HIGH
  pinMode(startButtonPin, INPUT_PULLUP);
  pinMode(stopButtonPin, INPUT_PULLUP);
  
  // Initialize output pins
  pinMode(led1Pin, OUTPUT);
  pinMode(led2Pin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  
  // Turn off all outputs initially
  digitalWrite(led1Pin, LOW);
  digitalWrite(led2Pin, LOW);
  digitalWrite(buzzerPin, LOW);
}

void loop() {
  // Read input states (buttons inverted because of pull-up, sensor direct reading)
  bool startPressed = !digitalRead(startButtonPin);
  bool stopPressed = !digitalRead(stopButtonPin);
  bool sensorState = digitalRead(sensorIRPin);  // Direct reading for active HIGH
  
  // Start button pressed
  if (startPressed && !isSystemActive) {
    isSystemActive = true;
    digitalWrite(led1Pin, HIGH);  // Turn on LED1
    lastSensorTrigger = millis();  // Start timing
  }
  
  // System is active
  if (isSystemActive && !isBuzzerActive) {
    // Check Sensor IR
    if (sensorState && !isSensorTriggered) {
      digitalWrite(led2Pin, HIGH);
      lastSensorTrigger = millis();  // Reset timer
      isSensorTriggered = true;
    }
    else if (!sensorState && isSensorTriggered) {
      digitalWrite(led2Pin, LOW);
      isSensorTriggered = false;
    }
    
    // Check if 2 minutes have passed without sensor trigger
    if (millis() - lastSensorTrigger >= 60000) {  // 2 minutes = 120000 ms
      digitalWrite(buzzerPin, HIGH);
      isBuzzerActive = true;
      buzzerStartTime = millis();
    }
  }
  
  // Buzzer is active
  if (isBuzzerActive) {
    // Check if stop button pressed or 1 minute passed
    if (stopPressed || (millis() - buzzerStartTime >= 60000)) {  // 1 minute = 60000 ms
      // Reset system
      digitalWrite(buzzerPin, LOW);
      digitalWrite(led1Pin, LOW);
      digitalWrite(led2Pin, LOW);
      isSystemActive = false;
      isBuzzerActive = false;
    }
  }
}