#include <Adafruit_NeoPixel.h>    // library for NeoPixels
#include <Encoder.h>              // library for rotary encoder

#define PIN_NEO_PIXEL D3          // Xiao pin that connects to NeoPixel
#define NUM_PIXELS 1              // number of LEDs
#define dt D8                     // Xiao pin that connects to rotary encoder dt
#define clk D10                   // Xiao pin that connects to rotary encoder clk
#define sw D9                     // Xiao pin that connects to rotary encoder sw

Adafruit_NeoPixel NeoPixel(NUM_PIXELS, PIN_NEO_PIXEL, NEO_GRB + NEO_KHZ800); // set the NeoPixel initialization
Encoder brightness(dt,clk);                                                  // initiate rotary encoder

int encoder_value = 0;            // value of rotary encoder
int brightness_value = 255;       // brightness value for the NeoPixel
int brightness_value_old = 255;   // previous brightness value for the NeoPixel
bool sw_control = false;

void setup() {
  Serial.begin(9600);              // initial serial communication with a baud rate of 9600
  NeoPixel.begin();                // initialize the NeoPixel strip object
  pinMode(sw, INPUT);              // set pin for rotary encoder button as an input
}

void IRAM_ATTR fallout()
{
  if (sw_control == false){
    brightness_value = brightness_value_old;
    sw_control = true;
  }
  else if (sw_control == true){
    brightness_value_old = brightness_value;
    brightness_value = 0;
    sw_control = false;
  }
}

void loop() {
  for (int i = 0; i < 256; i++) {
    byte r = (i < 85) ? i * 3 : (i < 170) ? 255 - (i - 85) * 3 : 0;
    byte g = (i < 85) ? 255 - i * 3 : (i < 170) ? 0 : (i - 170) * 3;
    byte b = (i < 85) ? 0 : (i < 170) ? (i - 85) * 3 : 255 - (i - 170) * 3;

    if (encoder_value != brightness.read()){
      encoder_value = brightness.read();
      brightness_value = encoder_value;
    }
    Serial.println(brightness_value);

    NeoPixel.setPixelColor(0, r, g, b);                // set color
    NeoPixel.setBrightness(brightness_value);
    NeoPixel.show();                                   // output the color
    attachInterrupt(sw, fallout, HIGH);
    delay(10);                                         // short delay for the color change
  } 
}