#include <FastLED.h>

#define NUM_LEDS 20
#define BASE_HUE 180
#define DATA_PIN 2
#define IN_PIN_POTM A0

CRGB leds[NUM_LEDS];

void setup() {
  // put your setup code here, to run once:
  FastLED.addLeds<WS2812B, DATA_PIN, GRB>(leds, NUM_LEDS);

  // Set up potentiometer
  Serial.begin(115200);
  pinMode(IN_PIN_POTM, INPUT);
}

void loop() {
  HSVForMe();
}

void HSVForMe() {
  for(int i = 0; i < NUM_LEDS; i++)
  {
    uint8_t mappedIndex = map(i, 0, NUM_LEDS - 1, 0, 255);
    leds[i] = CHSV(BASE_HUE, 255, triwave8(mappedIndex));
  }
  FastLED.show();
}

void MapPotentiometer() {
  // First clear any lit LEDs
  FastLED.clear();

  int potVal = analogRead(IN_PIN_POTM);
  int mappedLED = map(potVal, 0, 1023, 0, NUM_LEDS-1);
  
  leds[mappedLED] = CRGB::Amethyst;
  FastLED.show();
  delay(100);
}

void SimpleCycle() {
  for(int i = 0; i < NUM_LEDS; i++)
  {
    leds[i] = CRGB::Amethyst;
    FastLED.show();
    delay(100);

    /* Instead of some logic finding the *previous* LED and set that to
    black (unless this is LED[0] etc.) just set the *current* LED to black
    before looping to the *next* LED */

    leds[i] = CRGB::Black;
  }
}