const int ledPins[8] = {13, 12, 14, 27, 26, 25, 33, 32};
const int potPin = 34;

unsigned long previousMillis = 0;
const long interval = 150; 

int zone = 0;     
int step = 0;
int direction = 1; 

void turnOffAll() {
  for (int i = 0; i < 8; i++) {
    digitalWrite(ledPins[i], LOW);
  }
}

void setup() {
  for (int i = 0; i < 8; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
  pinMode(potPin, INPUT);
}

void loop() {
  int potValue = analogRead(potPin); 

  int newZone;
  if (potValue <= 1365) {
    newZone = 1;
  } else if (potValue <= 2730) {
    newZone = 2;
  } else {
    newZone = 3;
  }


  if (newZone != zone) {
    zone = newZone;
    step = 0;
    direction = 1;
    turnOffAll();
  }

  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;
    turnOffAll();

    if (zone == 1) {

      digitalWrite(ledPins[step], HIGH);
      step++;
      if (step >= 8) step = 0;

    } else if (zone == 2) {
      // --- Bounce / ping-pong ---
      digitalWrite(ledPins[step], HIGH);
      step += direction;
      if (step >= 7) { step = 7; direction = -1; }
      if (step <= 0) { step = 0; direction = 1; }

    } else if (zone == 3) {

      int left  = 3 - step; 
      int right = 4 + step; 
      if (left >= 0)  digitalWrite(ledPins[left], HIGH);
      if (right <= 7) digitalWrite(ledPins[right], HIGH);
      step++;
      if (step > 3) step = 0;
    }
  }
}