#include <FastLED.h>

#define LED_PIN     6
#define COLOR_ORDER GRB
#define CHIPSET     WS2812B
#define NUM_LEDS    144

#define BRIGHTNESS  255
#define FRAMES_PER_SECOND 24

CRGB leds[NUM_LEDS];

void setup() {
  FastLED.addLeds<CHIPSET, LED_PIN, COLOR_ORDER>(leds, NUM_LEDS).setCorrection( TypicalLEDStrip );
  FastLED.setBrightness( BRIGHTNESS );
}

void loop() {
  ledsOn();

  FastLED.delay(5000);

  for(int i=NUM_LEDS;i>0;i--){
    leds[i] = CHSV( 0, 0, 0);
    FastLED.show();
    FastLED.delay(1000 / FRAMES_PER_SECOND);
  }

  FastLED.delay(5000);
}

void ledsOn() {
  for(int i=0;i<NUM_LEDS;i++){
    int b = map(i, 0, NUM_LEDS, 0, 255);
    leds[i] = CHSV(255,0,b);
    FastLED.show();
    FastLED.delay(1000 / FRAMES_PER_SECOND);
  }
  for(int i=NUM_LEDS;i>0;i--){
    leds[i] = CHSV(255,0,255);
    FastLED.show();
    FastLED.delay(1000 / FRAMES_PER_SECOND);
  }
}