#include <Servo.h>

#define SPEEDBUMP_SERVO_PIN 9
#define LDR_PIN 3
#define IR_SENSOR_1_PIN 4
#define IR_SENSOR_2_PIN 5
#define STREET_LIGHTS_RELAY_PIN 6
#define ULTRASONIC_TRIG 10
#define ULTRASONIC_ECHO 8

Servo speedBumpServo;

const float distanceBetweenIRs = 22.0;
unsigned long timeIR1 = 0;
unsigned long timeIR2 = 0;
float vehicleSpeed = 0;
const float speedLimit = 10.0;

unsigned long lightOnTime = 0;
const unsigned long lightDuration = 10000;
bool lightState = false;

float readUltrasonic() {
  digitalWrite(ULTRASONIC_TRIG, LOW);
  delayMicroseconds(2);
  digitalWrite(ULTRASONIC_TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(ULTRASONIC_TRIG, LOW);

  long duration = pulseIn(ULTRASONIC_ECHO, HIGH, 30000);
  float distance = (duration * 0.034) / 2;
  return distance;
}

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

  pinMode(IR_SENSOR_1_PIN, INPUT);
  pinMode(IR_SENSOR_2_PIN, INPUT);
  pinMode(LDR_PIN, INPUT);
  pinMode(ULTRASONIC_TRIG, OUTPUT);
  pinMode(ULTRASONIC_ECHO, INPUT);
  pinMode(STREET_LIGHTS_RELAY_PIN, OUTPUT);

  speedBumpServo.attach(SPEEDBUMP_SERVO_PIN);
  speedBumpServo.write(0);

  Serial.println("Arduino System Initialized");
}

void loop() {
  unsigned long currentMillis = millis();

  bool isNight = (digitalRead(LDR_PIN) == HIGH);

  if (isNight) {
    float distance = readUltrasonic();

    if (distance > 0 && distance <= 20.0) {
      lightState = true;
      lightOnTime = currentMillis;
      digitalWrite(STREET_LIGHTS_RELAY_PIN, HIGH);
      Serial.println("Vehicle detected → Light ON");
    }

    // Turn OFF after 20 seconds
    if (lightState && (currentMillis - lightOnTime >= lightDuration)) {
      lightState = false;
      digitalWrite(STREET_LIGHTS_RELAY_PIN, LOW);
      Serial.println("20s elapsed → Light OFF");
    }
  } else {
    lightState = false;
    digitalWrite(STREET_LIGHTS_RELAY_PIN, LOW);
  }

  static bool sensor1Triggered = false;
  static bool sensor2Triggered = false;

  bool ir1 = !digitalRead(IR_SENSOR_1_PIN);
  bool ir2 = !digitalRead(IR_SENSOR_2_PIN);

  if (ir1 && !sensor1Triggered) {
    timeIR1 = millis();
    sensor1Triggered = true;
  }

  if (ir2 && sensor1Triggered && !sensor2Triggered) {
    timeIR2 = millis();
    sensor2Triggered = true;

    unsigned long timeDiff = timeIR2 - timeIR1;
    if (timeDiff > 0) {
      vehicleSpeed = (distanceBetweenIRs * 1000.0) / timeDiff;

      Serial.print("Vehicle Speed: ");
      Serial.print(vehicleSpeed);
      Serial.println(" cm/s");

      if (vehicleSpeed > speedLimit) {
        speedBumpServo.write(15);
        Serial.println("SPEED VIOLATION! Bump Raised");

        unsigned long bumpTime = millis();
        while (millis() - bumpTime < 3000) {
          // system keeps running
        }

        speedBumpServo.write(0);
        Serial.println("Bump Lowered");
      }
    }

    sensor1Triggered = false;
    sensor2Triggered = false;
  }

  if (sensor1Triggered && (millis() - timeIR1 > 5000)) {
    sensor1Triggered = false;
  }
}