#include "Ultrasonic.h"

#define TRIG_PIN 13
#define ECHO_PIN 12
#define RELAY_PIN 2
#define BUZZER_PIN 3
#define LED1_PIN 4
#define LED2_PIN 5
#define LED3_PIN 6

Ultrasonic ultrasonic(TRIG_PIN, ECHO_PIN);

const int DISTANCE_THRESHOLD = 50;
const unsigned int TIME_INTERVAL = 10000;

void setup() {
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED1_PIN, OUTPUT);
  pinMode(LED2_PIN, OUTPUT);
  pinMode(LED3_PIN, OUTPUT);
}

void flashLED(int pin, unsigned long startTime, unsigned long duration) {
  if (millis() - startTime > duration) {
    digitalWrite(pin, HIGH);
  } else {
    digitalWrite(pin, LOW);
  }
}

void loop() {
  int distance = ultrasonic.read(CM);

  if (distance < DISTANCE_THRESHOLD) {
    digitalWrite(RELAY_PIN, HIGH);
    digitalWrite(BUZZER_PIN,LOW);
    unsigned long startTime = millis();

    do {
      flashLED(LED1_PIN, startTime, TIME_INTERVAL / 3);
      flashLED(LED2_PIN, startTime, TIME_INTERVAL / 3 * 2);
      flashLED(LED3_PIN, startTime, TIME_INTERVAL);

    } while (ultrasonic.read(CM) < DISTANCE_THRESHOLD);

    digitalWrite(RELAY_PIN, LOW);
    digitalWrite(LED1_PIN, LOW);
    digitalWrite(LED2_PIN, LOW);
    digitalWrite(LED3_PIN, LOW);

    unsigned long stopTime = millis();

    if (stopTime - startTime < TIME_INTERVAL) {
      digitalWrite(BUZZER_PIN, HIGH);
    } else {
      digitalWrite(BUZZER_PIN, LOW);
    }
  }
}