#include <FastLED.h>

#define LED_PIN     2
#define NUM_LEDS    60
#define BRIGHTNESS  255
#define LED_TYPE    WS2811
#define COLOR_ORDER GRB
CRGB leds[NUM_LEDS];

// CHANGE THIS VALUE TO CONTROL SPEED
// Higher value = Faster animation
#define UPDATES_PER_SECOND 150

CRGBPalette16 currentPalette;
TBlendType    currentBlending;

int8_t animationDirection = 1;
unsigned long lastDirectionChangeTime = 0;
const unsigned long directionChangeInterval = 5000; // Animation reverses every 5 seconds

void setup() {
  delay(800); // Power-up delay

  FastLED.addLeds<LED_TYPE, LED_PIN, COLOR_ORDER>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);
  FastLED.setBrightness(BRIGHTNESS);

  currentPalette = RainbowStripeColors_p;
  currentBlending = NOBLEND;

  lastDirectionChangeTime = millis();
}

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

  // Reverse the animation direction every few seconds
  if (currentTime - lastDirectionChangeTime >= directionChangeInterval) {
    animationDirection *= -1;
    lastDirectionChangeTime = currentTime;
  }

  // This static variable keeps track of the animation's position
  static uint8_t startIndex = 0;
  startIndex = startIndex + animationDirection; // Move the animation forwards or backwards

  // Fill the LED strip with colors from the palette
  FillLEDsFromPaletteColors(startIndex);

  FastLED.show();
  // The delay is now shorter because UPDATES_PER_SECOND is higher
  FastLED.delay(1000 / UPDATES_PER_SECOND);
}

// This function fills the strip with colors from the palette.
void FillLEDsFromPaletteColors(uint8_t colorIndex) {
  uint8_t brightness = 255;

  for (int i = 0; i < NUM_LEDS; i++) {
    leds[i] = ColorFromPalette(currentPalette, colorIndex, brightness, currentBlending);
    
    // This value controls the width of the color bands (set to 5 for ~3 pixel trails)
    colorIndex += 5; 
  }
}