#include <Adafruit_NeoPixel.h>

#define NUM_PIXELS 64
#define buttonPin 12
Adafruit_NeoPixel strip(NUM_PIXELS, 6, NEO_GRB + NEO_KHZ800);
uint8_t counter = 0;
bool currentButtonState = 0;
bool lastButtonState = 0;

void setup() {
  Serial.begin(9600);

  pinMode(buttonPin, INPUT);

  strip.begin();
  strip.clear();
  strip.show();
}

void rotateGradient(uint8_t gradientSize, uint16_t delayval) {
  uint8_t numPixel = NUM_PIXELS, colorSet = 0;
  for (uint8_t r = 1; r < 4; r++) {
    for (int16_t i = - numPixel / gradientSize; i < (numPixel + (numPixel / gradientSize)); i++) {
      strip.clear();
      for (uint8_t j = 0; j < (numPixel / gradientSize); j++) {
        colorSet = r;
        currentButtonState = digitalRead(buttonPin);
        if (currentButtonState != lastButtonState && currentButtonState == HIGH) return;

        if(r == 1) {
          strip.setPixelColor((i + j), strip.Color(255 - (255 / (numPixel / gradientSize)) * j, 0, 0)); 
          strip.setPixelColor((i - j), strip.Color(255 - (255 / (numPixel / gradientSize)) * j, 0, 0));
        } else if(r == 2) {
          strip.setPixelColor((i + j), strip.Color(0, 255 - (255 / (numPixel / gradientSize)) * j, 0)); 
          strip.setPixelColor((i - j), strip.Color(0, 255 - (255 / (numPixel / gradientSize)) * j, 0));
        } else {
          strip.setPixelColor((i + j), strip.Color(0, 0, 255 - (255 / (numPixel / gradientSize)) * j));
          strip.setPixelColor((i - j), strip.Color(0, 0, 255 - (255 / (numPixel / gradientSize)) * j));
        }
        
      }
      delay(delayval);
      strip.show();
    }
  }
}

void colorTransitionFadeOut(uint16_t delayval, uint8_t r, uint8_t g, uint8_t b) {
  uint8_t numPixel = NUM_PIXELS;

    for(int i = 0; i < numPixel; i++) { \
      currentButtonState = digitalRead(buttonPin);
      if (currentButtonState != lastButtonState && currentButtonState == HIGH) return;
      
      strip.setPixelColor(i, strip.Color(r, g, b));
      strip.show();   
      delay(delayval); 
    }
    for(int i=0; i < numPixel; i++) { 
      currentButtonState = digitalRead(buttonPin);
      if (currentButtonState != lastButtonState && currentButtonState == HIGH) return;

      strip.setPixelColor(i, strip.Color(0, 0, 0));
      strip.show();   
      delay(delayval); 
  }
}

void rotateInOrder (uint16_t delayval) {

  colorTransitionFadeOut(delayval, 255, 0, 0);
  colorTransitionFadeOut(delayval, 255, 165, 0); //橘
  colorTransitionFadeOut(delayval, 255, 255, 0);
  colorTransitionFadeOut(delayval, 0, 255, 0);
  colorTransitionFadeOut(delayval, 0, 0, 255);
  colorTransitionFadeOut(delayval, 75, 0, 130); //靛
  colorTransitionFadeOut(delayval, 128, 0, 128); //紫
}

void Wheel(uint8_t wheelPos, uint8_t &r, uint8_t &g, uint8_t &b) {
  if (wheelPos <= 85) {
    r = 255 - wheelPos * 3;
    g = wheelPos * 3;
    b = 0;
  } else if (wheelPos <= 170) {
    wheelPos -= 85;
    r = 0;
    g = 255 - wheelPos * 3;
    b = wheelPos * 3;
  } else {
    wheelPos -= 170;
    r = wheelPos * 3;
    g = 0;
    b = 255 - wheelPos * 3;
  }
}

void rainbow() {
  uint8_t wheelPos, numPixel = NUM_PIXELS;
  uint8_t r, g, b;

    for (uint8_t i = 0; i < numPixel; i++) {
      wheelPos = i * (256 / numPixel);
      Wheel(wheelPos, r, g, b);
      strip.setPixelColor(i, strip.Color(r, g, b));
  }
  strip.show();
}

void rotateRainbow(uint16_t delayval, uint8_t repeatTimes) {
  uint8_t numPixel = NUM_PIXELS;
  uint8_t currentWheelPos = 0, wheelPos = 0, count = 0, k = -1;
  uint8_t interval = 256 / numPixel;
  uint8_t r, g, b;

  while(true) {
    currentButtonState = digitalRead(buttonPin);
    if (currentButtonState != lastButtonState && currentButtonState == HIGH) return;

    for (uint8_t i = 0; i < numPixel; i++) {
      wheelPos = ((i + currentWheelPos) * interval) % 256;
      Wheel(wheelPos, r, g, b);
      strip.setPixelColor(i, strip.Color(r, g, b));
    }

    strip.show();
    delay(delayval);
    count++;
    currentWheelPos += k;

    Serial.println(count);
    if (count >= repeatTimes * numPixel) {
      k *= -1;
      count = 0;
    }
  }
}

void process () {
  switch (counter) {
      case 0:
        rainbow();
        break;
      case 1:
        rotateGradient(3, 30);
        break;
      case 2:
        rotateInOrder(10);
        break;
      default:
        rotateRainbow(50, 3);
        break;
  }
}

void loop() {
  currentButtonState = digitalRead(buttonPin);

  if (currentButtonState != lastButtonState && currentButtonState == LOW) {
    strip.clear();
    counter %= 4;
    Serial.println(counter);

    process();
    counter++;
  }
  else {
    process();
  }
  lastButtonState = currentButtonState;
  delay(10);
}