#include <ESP32Encoder.h>
#include <FastLED.h>

#define CLK_PIN 13
#define DT_PIN  14
#define SW_PIN  15
#define LED_PIN 38
#define NUM_LEDS 1

ESP32Encoder encoder;
CRGB leds[NUM_LEDS];

void setup() {
  Serial.begin(115200);
  ESP32Encoder::useInternalWeakPullResistors = puType::up;
  encoder.attachHalfQuad(DT_PIN, CLK_PIN);
  encoder.setCount(0);
  pinMode(SW_PIN, INPUT_PULLUP);
  FastLED.addLeds<WS2812B, LED_PIN, GRB>(leds, NUM_LEDS);
}

void loop() {
  if (encoder.getCount() < 0)  encoder.setCount(0);
  if (encoder.getCount() > 20) encoder.setCount(20);

  float brightness = (255.0 / 20.0) * encoder.getCount();
  leds[0] = CHSV(20, 255, brightness);
  FastLED.show();

  Serial.println(brightness);

  if (digitalRead(SW_PIN) == LOW) {
    encoder.setCount(0);
    delay(200);
  }

  delay(50);
}