#include <Servo.h>

const int ldrPin = A0;
const int trigPin = 9;
const int echoPin = 10;
const int ledPin = 13;
const int servoPin = 6;

Servo barrierServo;

const int ldrThreshold = 400;
const int distanceThreshold = 20;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(ledPin, OUTPUT);
  barrierServo.attach(servoPin);
  Serial.begin(9600);
}

void loop() {
  int ldrValue = analogRead(ldrPin);
  Serial.print("LDR: "); Serial.println(ldrValue);

  // Read distance
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  long duration = pulseIn(echoPin, HIGH);
  int distance = duration * 0.034 / 2;
  Serial.print("Distance: "); Serial.println(distance);

  if (ldrValue < ldrThreshold && distance < distanceThreshold) {
    digitalWrite(ledPin, HIGH);        // Light ON
    barrierServo.write(90);            // Barrier Up
  } else {
    digitalWrite(ledPin, LOW);         // Light OFF
    barrierServo.write(0);             // Barrier Down
  }

  delay(200);
}