// Forum: https://forum.arduino.cc/t/how-backwards-functions-in-code/1101167
// This Wokwi project: https://wokwi.com/projects/359119719077946369
// Previous sketch: https://wokwi.com/projects/359074849643556865
// The first sketch: https://wokwi.com/projects/359042982266722305

// This is the same as the previous sketch, but now the leds go in the other directions.

const int LED_COUNT = 6;
int LED_PINS[LED_COUNT] = {3, 5, 6, 9, 10, 11};

int currentPosition = 0;
const int delayTime = 400;

void setup() 
{
  for (int i = 0; i < LED_COUNT; i++) 
  {
    pinMode(LED_PINS[i], OUTPUT);   // OUTPUT and default also LOW
  }
}

void loop() 
{
  // Intro sequence
  // Roll in a led from the most right position to the left.
  // Keep the left led on, and continue with the next led
  for (int i=LED_COUNT-1; i>=0; i--)     // start with the most left led
  {
    for (int j=0; j<=i; j++)             // roll in leds from the right
    {
      digitalWrite(LED_PINS[j], HIGH);
      delay(delayTime);
      if (j!=i)                          // keep the current led on
      {
        digitalWrite(LED_PINS[j], LOW);
      }
    }
  }

  // All the leds are on now.
  delay(2000);

  // Outro sequence
  // Leds are rolling out to the right, until all are off
  for (int i=0; i<LED_COUNT; i++)      // start with the most right led
  {
    for (int j=i; j>=0; j--)           // roll out leds to the right
    {
      if (j!=i)                        // keep the current led off
      {
        digitalWrite(LED_PINS[j], HIGH);
      }
      delay(delayTime);
      digitalWrite(LED_PINS[j], LOW);
    }
  }

  // All the leds are off now.
  delay(2000);
}