#include <Adafruit_NeoPixel.h>

void HSVtoRGB(float H, float S,float V,int &R, int &G, int &B){
    while(H>360) H-=360;
    if(H>360 || H<0 || S>100 || S<0 || V>100 || V<0){
        return;
    }
    float s = S/100;
    float v = V/100;
    float C = s*v;
    float X = C*(1-abs(fmod(H/60.0, 2)-1));
    float m = v-C;
    float r,g,b;
    if(H >= 0 && H < 60){
        r = C,g = X,b = 0;
    }
    else if(H >= 60 && H < 120){
        r = X,g = C,b = 0;
    }
    else if(H >= 120 && H < 180){
        r = 0,g = C,b = X;
    }
    else if(H >= 180 && H < 240){
        r = 0,g = X,b = C;
    }
    else if(H >= 240 && H < 300){
        r = X,g = 0,b = C;
    }
    else{
        r = C,g = 0,b = X;
    }
    R = (r+m)*255;
    G = (g+m)*255;
    B = (b+m)*255;
}



#define PIN1            0
#define NUMPIXELS      25 // 24
#define CENTER 12.5
int mode;
Adafruit_NeoPixel pixels[] = {
  Adafruit_NeoPixel(NUMPIXELS, PIN1, NEO_GRB + NEO_KHZ800),
};
int PIN_COUNT = 1;
double hue = 0.0;
 void setup() {    
    
   pinMode(13, OUTPUT); //LED on Model A   
   pinMode(10, INPUT); //LED on Model A   
   digitalWrite(13, LOW); //LED on Model A   
   pinMode(PIN1, OUTPUT); 
    pixels[0].begin();
    randomSeed(analogRead(10));
    mode = random(1,4);
    for(int i=0;i<=mode;i++) {
     digitalWrite(13, LOW); //LED on Model A   
     delay(100);
     digitalWrite(13, HIGH); //LED on Model A   
     delay(100);
    }
 }

 // the loop routine runs over and over again forever:
 void loop() {
    static double power = 1.5;
    static double fac = 0.5/pow(0.5,power); 
      for(int i=0;i<NUMPIXELS;i++){
        int r,g,b;
        int hueOffset = (abs(CENTER-i)/(float)CENTER) * 50 * ( mode );
        double h = (hue + hueOffset)/360.,y;
        while(h>1) h-=1;
        if(h<=0.5)
          y = pow(h,power)*fac;
        else 
          y = 1-pow(1-h,power)*fac;

        HSVtoRGB(y*360, 100, 55,r,g,b);   
        pixels[0].setPixelColor(i, pixels[0].Color(r,g,b)); // Moderately bright green color.
      }
      pixels[0].show(); // This sends the updated pixel color to the hardware.

   hue -= 0.4;
   if(hue>=360) {
    hue -= 360;
   }
   if(hue<=0) {
    hue = 360 + hue;
   }
      // digitalWrite(1, LOW); //LED on Model A   
    delay(15); // Delay for a period of time (in milliseconds).
    digitalWrite(13, LOW); //LED on Model A   
  }