#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() > 40) encoder.setCount(40);

  float t = encoder.getCount() / 40.0;

  uint8_t hue = 160 - (t * 140);
  uint8_t sat = t * 220;
  uint8_t val = 180;

  leds[0] = CHSV(hue, sat, val);
  FastLED.show();

  Serial.println(t);

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

  delay(50);
}