#include <FastLED.h>

#define NUM_STRIPS 3
#define NUM_LEDS_PER_STRIP 24
#define NUM_LEDS NUM_LEDS_PER_STRIP * NUM_STRIPS 
#define BRIGHTNESS  255      // 255 is full brightness, 128 is half
#define MIN_BRIGHTNESS 8                   // watch the power!
#define MAX_BRIGHTNESS 255                   // watch the power!



CRGB leds[NUM_LEDS];

//reorder LEDs sequence
int db[] = {2,3,1,4,0,5,8,6,7,
            13,14,12,15,11,16,10,17,9,
            25,24,26,23,18,22,19,21,20};
           
void setup() {
  delay( 2000 ); // power-up safety delay
  //Set all lights to make sure all are working as expected
  // Assign pin 3, 5 and 6 as LED singal pin
  FastLED.addLeds<NEOPIXEL, 3>(leds, 0, NUM_LEDS_PER_STRIP);
  FastLED.addLeds<NEOPIXEL, 5>(leds, NUM_LEDS_PER_STRIP, NUM_LEDS_PER_STRIP);
  FastLED.addLeds<NEOPIXEL, 6>(leds, NUM_LEDS_PER_STRIP*2, NUM_LEDS_PER_STRIP);

  FastLED.setBrightness( BRIGHTNESS );

  //set rainbow background
  fill_rainbow(leds, NUM_LEDS, 0, 9);
  FastLED.show();
  delay(1000);
  

}

void loop() {

  
 


   //clear background
   fill_solid(leds, NUM_LEDS, CRGB::Black);

   for(int n = 0; n < NUM_LEDS; n++) {
    
      meteorRain(10, 32, true, 30, n);
     
      leds[db[n]] = CHSV(n*9,255,255);
      FastLED.show();
   }
   
  
   
}

void meteorRain(byte meteorSize, byte meteorTrailDecay, boolean meteorRandomDecay, int SpeedDelay, int n) {  
 
 
  //for(int i = 0; i < NUM_LEDS+NUM_LEDS; i++) {
  //change the above loop for reversed direction
   for(int i = NUM_LEDS+NUM_LEDS; i > n; i--) {
   
    // fade brightness LEDs one step
    // j=n fade less by each step; j=0 fade all in each step
    for(int j=n; j<NUM_LEDS; j++) {
        if( (!meteorRandomDecay) || (random(10)>5) ) {
        fadeToBlack(j, meteorTrailDecay );        
      }
    }
   
    // draw meteor
    for(int j = 0; j < meteorSize; j++) {
      if( ( i-j <NUM_LEDS) && (i-j>=0) ) {
        leds[db[i-j]] = CHSV((i-j)*9,255,255);
      }
    }
   
    FastLED.show();
    delay(SpeedDelay);
  }
}

void fadeToBlack(int ledNo, byte fadeValue) {
 
   leds[db[ledNo]].fadeToBlackBy( fadeValue );
   
}