#include <Adafruit_NeoPixel.h>

#define PIN 6
#define NUM_PIXELS 6

Adafruit_NeoPixel pixels = Adafruit_NeoPixel(NUM_PIXELS, PIN, NEO_GRB + NEO_KHZ800);

int currentPixel = 0;
unsigned long previousMillis = 0;
unsigned long interval = 100;
unsigned long totalTime = 25000;
unsigned long startTime;

bool finished = false;
bool fadeStarted = false;
unsigned long fadeStartTime;
unsigned long finishTime;

int pixelBrightness[NUM_PIXELS];
unsigned long pixelStartTime[NUM_PIXELS];
unsigned long pixelLastFadeTime[NUM_PIXELS];

unsigned long fadeInterval = 50;
int fadeSteps = 20;
int fadeAmount = 255 / fadeSteps;

void setup() {
  pixels.begin();
  startTime = millis();
  randomSeed(analogRead(0)); // Seed randomness
}

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

  // Phase 1: Running light pattern
  if (currentMillis - previousMillis >= interval && currentMillis - startTime <= totalTime) {
    previousMillis += interval;

    pixels.setPixelColor(currentPixel, pixels.Color(0, 0, 255));
    pixels.show();
    pixels.setPixelColor(currentPixel, pixels.Color(0, 0, 0));

    currentPixel++;
    if (currentPixel >= NUM_PIXELS) currentPixel = 0;
  }

  if (currentMillis - startTime <= totalTime) {
    interval = map(currentMillis - startTime, 0, totalTime, 100, 10);
  }

  // Phase 2: Turn all white and prep fade
  if (!finished && currentMillis - startTime > totalTime) {
    finishTime = currentMillis;
    startFadeOutRandom(finishTime);
    finished = true;
  }

  // Phase 3: Run the actual fade-out logic
  if (fadeStarted) {
    fadeOutRandom();
  }
}








// === Function: Set up the fade parameters for each pixel ===
void startFadeOutRandom(unsigned long currentTime) {
  for (int i = 0; i < NUM_PIXELS; i++) {
    pixels.setPixelColor(i, pixels.Color(255, 255, 255));
    pixelBrightness[i] = 255;
    pixelStartTime[i] = currentTime + random(500, 2500); // Unique start delay per pixel
    pixelLastFadeTime[i] = currentTime;
  }
  pixels.show();
  fadeStartTime = currentTime;
  fadeStarted = true;
}

// === Function: Fade out pixels individually with random timing ===
void fadeOutRandom() {
  unsigned long currentMillis = millis();
  bool anyStillFading = false;

  for (int i = 0; i < NUM_PIXELS; i++) {
    if (currentMillis >= pixelStartTime[i] && pixelBrightness[i] > 0) {
      if (currentMillis - pixelLastFadeTime[i] >= fadeInterval) {
        pixelBrightness[i] -= fadeAmount;
        if (pixelBrightness[i] < 0) pixelBrightness[i] = 0;

        pixels.setPixelColor(i, pixels.Color(pixelBrightness[i], pixelBrightness[i], pixelBrightness[i]));
        pixelLastFadeTime[i] = currentMillis;
      }
    }
    if (pixelBrightness[i] > 0) {
      anyStillFading = true;
    }
  }

  if (anyStillFading) {
    pixels.show();
  } else {
    fadeStarted = false; // Optional: Stop calling the function once fully faded
  }
}