// Pins for LEDs
const int ledPins[] = {3, 4, 5, 6, 7};

// Pins for IR sensors
const int bottomIRPin = 9; // Bottom sensor
const int topIRPin = 8;    // Top sensor

// Delay between LED transitions
const int transitionDelay = 500; // milliseconds

void setup() {
  // Initialize LED pins as outputs
  for (int i = 0; i < sizeof(ledPins) / sizeof(ledPins[0]); i++) {
    pinMode(ledPins[i], OUTPUT);
  }
  
  // Initialize IR sensor pins as inputs
  pinMode(bottomIRPin, INPUT);
  pinMode(topIRPin, INPUT);
}

void loop() {
  // Check if obstacle is detected by the bottom IR sensor
  if (detectObstacle(bottomIRPin)) {
    // Start the LED transition from bottom to top
    lightUpLEDsBottomToTop();
    delay(100); // Wait for 2 seconds
    turnOffLEDs();
    // Wait for IR sensor to reset
    while (digitalRead(bottomIRPin) == HIGH) {}
  }
  
  // Check if obstacle is detected by the top IR sensor
  if (detectObstacle(topIRPin)) {
    // Start the LED transition from top to bottom
    lightUpLEDsTopToBottom();
    delay(100); // Wait for 2 seconds
    turnOffLEDs();
    // Wait for IR sensor to reset
    while (digitalRead(topIRPin) == HIGH) {}
  }
}

// Function to detect obstacles using IR sensor
bool detectObstacle(int irPin) {
  // Check if IR sensor input is HIGH (indicating obstacle)
  return digitalRead(irPin) == HIGH;
}

// Function to light up LEDs one by one from bottom to top
void lightUpLEDsBottomToTop() {
  for (int i = 0; i < sizeof(ledPins) / sizeof(ledPins[0]); i++) {
    digitalWrite(ledPins[i], HIGH);
    delay(transitionDelay);
  }
}

// Function to light up LEDs one by one from top to bottom
void lightUpLEDsTopToBottom() {
  for (int i = sizeof(ledPins) / sizeof(ledPins[0]) - 1; i >= 0; i--) {
    digitalWrite(ledPins[i], HIGH);
    delay(transitionDelay);
  }
}

// Function to turn off LEDs in reverse order
void turnOffLEDs() {
  for (int i = sizeof(ledPins) / sizeof(ledPins[0]) - 1; i >= 0; i--) {
    digitalWrite(ledPins[i], LOW);
    delay(transitionDelay); // Optional delay for better visual effect
  }
}