/* ESP32 LED Strip animation (back and forth with gradient)

  Displays a light going back and forth with a gradient tail
*/
#include <FastLED.h>

#define DATA_PIN 26 
#define CLOCK_PIN 13
#define ledCount 20

CRGB leds[ledCount];

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, ledCount);  // GRB ordering is assumed
}

int direction = 1; // 1 for left, -1 for right
int currentLED = 0;

void loop() {
  delay(10); // this speeds up the simulation

  // Clear all LEDs
  for (int j = 0; j < ledCount; j++) {
    leds[j] = CRGB::Black;
  }

  leds[currentLED] = CHSV(160, 255, 255);

  // Add gradient tail
  if (currentLED - direction <= ledCount-1 && currentLED - direction >= 0) {
    leds[currentLED - direction] = CHSV(160, 255, 200);
  }
  if (currentLED - (direction * 2) <= ledCount-1 && currentLED - (direction * 2) >= 0) {
    leds[currentLED - (direction * 2)] = CHSV(160, 255, 155);
  }
  if (currentLED - (direction * 3) <= ledCount-1 && currentLED - (direction * 3) >= 0) {
    leds[currentLED - (direction * 3)] = CHSV(160, 255, 100);
  }
  if (currentLED - (direction * 4) <= ledCount-1 && currentLED - (direction * 4) >= 0) {
    leds[currentLED - (direction * 4)] = CHSV(160, 255, 55);
  }
  if (currentLED - (direction * 5) <= ledCount-1 && currentLED - (direction * 5) >= 0) {
    leds[currentLED - (direction * 5)] = CHSV(160, 255, 10);
  }

  // Switch direction
  if (currentLED + direction > ledCount-1 || currentLED + direction < 0) {
    direction = direction * -1;
  }

  currentLED = currentLED + direction;
  FastLED.show();

  delay(60);
}