// Library free version, using HSV --> RGB code not by me 
//#include < FastLED.h >
int light = 0;
int oldavg = 0;
void setup() {
  Serial.begin(9600);
  pinMode(13, OUTPUT);
}

void loop() {
  int ss = 20; // sample size for light sensor
  int average = 0;
  for (int x = 0; x < ss; x++) {
    // mapping to correct values
    average += map(analogRead(0), 0, 1023, 0, 127);
    delay(3);
  }
  average /= ss;
  //Serial.println(analogRead(0));
  //Serial.println(average);
  if (oldavg == 0) {
    oldavg = average;
  }
  if (abs(oldavg - average) > 1) {
    Serial.print("Goal: ");
    Serial.println(average);
    digitalWrite(13, HIGH);
    while (oldavg < average) {
      oldavg += 2;
      setColor(oldavg);
    }
    while (oldavg > average) {
      oldavg -= 2;
      setColor(oldavg);
    }
    digitalWrite(13, LOW);
  }
}

void setColor(int hue) {
  byte RedLight;
  byte GreenLight;
  byte BlueLight;

  // this is the algorithm to convert from RGB to HSV
  byte h = hue;
  byte s = 255;
  byte v = 60;
  h = (h * 192) / 256; // 0..191
  unsigned int i = h / 32; // We want a value of 0 thru 5
  unsigned int f = (h % 32) * 8; // 'fractional' part of 'i' 0..248 in jumps

  unsigned int sInv = 255 - s; // 0 -> 0xff, 0xff -> 0
  unsigned int fInv = 255 - f; // 0 -> 0xff, 0xff -> 0
  byte pv = v * sInv / 256; // pv will be in range 0 - 255
  byte qv = v * (256 - s * f / 256) / 256;
  byte tv = v * (256 - s * fInv / 256) / 256;

  switch (i) {
  case 0:
    RedLight = v;
    GreenLight = tv;
    BlueLight = pv;
    break;
  case 1:
    RedLight = qv;
    GreenLight = v;
    BlueLight = pv;
    break;
  case 2:
    RedLight = pv;
    GreenLight = v;
    BlueLight = tv;
    break;
  case 3:
    RedLight = pv;
    GreenLight = qv;
    BlueLight = v;
    break;
  case 4:
    RedLight = tv;
    GreenLight = pv;
    BlueLight = v;
    break;
  case 5:
    RedLight = v;
    GreenLight = pv;
    BlueLight = qv;
    break;
  }
  //CRGB& color = CHSV(average, 255, 255);
  Serial.print("Hue: ");
  Serial.print(hue);
  Serial.print(", RGB : ");
  Serial.print(RedLight);
  Serial.print(", ");
  Serial.print(GreenLight);
  Serial.print(", ");
  Serial.println(BlueLight);
  analogWrite(9, RedLight);
  analogWrite(10, GreenLight);
  analogWrite(11, BlueLight);
}