#include <Servo.h>

// Pin definitions
const uint8_t IR_PIN       = 2;
const uint8_t TRIG_PIN     = 6;
const uint8_t ECHO_PIN     = 5;
const uint8_t SERVO_PIN    = 9;
const uint8_t RELAY_PIN    = 7;
const uint8_t STEP_PIN     = 3;
const uint8_t DIR_PIN      = 4;
const uint8_t ENABLE_PIN   = 5;

Servo barrierServo;

const unsigned int STEPS_PER_REV = 200;
const unsigned long STEP_DELAY_US = 1000;

void setup() {
  Serial.begin(9600);
  pinMode(IR_PIN, INPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(STEP_PIN, OUTPUT);
  pinMode(DIR_PIN, OUTPUT);
  pinMode(ENABLE_PIN, OUTPUT);

  digitalWrite(RELAY_PIN, LOW);
  digitalWrite(ENABLE_PIN, LOW); // Enable stepper driver

  barrierServo.attach(SERVO_PIN);
  barrierServo.write(0); // Barrier down
}

void loop() {
  if (digitalRead(IR_PIN) == HIGH) {
    Serial.println("Vehicle detected");

    // Lift barrier
    barrierServo.write(90);
    delay(500);

    // Measure distance
    long duration, distance;
    digitalWrite(TRIG_PIN, LOW);
    delayMicroseconds(2);
    digitalWrite(TRIG_PIN, HIGH);
    delayMicroseconds(10);
    digitalWrite(TRIG_PIN, LOW);

    duration = pulseIn(ECHO_PIN, HIGH);
    distance = duration * 0.034 / 2;

    Serial.print("Distance: ");
    Serial.println(distance);

    // Warning light if vehicle is too close
    if (distance < 20) {
      digitalWrite(RELAY_PIN, HIGH);
      Serial.println("Warning: Vehicle too close");
    } else {
      digitalWrite(RELAY_PIN, LOW);
    }

    // Rotate signboard
    digitalWrite(DIR_PIN, HIGH);
    for (int i = 0; i < STEPS_PER_REV; i++) {
      digitalWrite(STEP_PIN, HIGH);
      delayMicroseconds(2);
      digitalWrite(STEP_PIN, LOW);
      delayMicroseconds(STEP_DELAY_US);
    }

    delay(2000); // Keep barrier open

    // Lower barrier
    barrierServo.write(0);
    digitalWrite(RELAY_PIN, LOW);
    delay(1000);
  }
}