//USBtinyISP(ATTinyCore) upload using programmer
//Atinny841(Optiboot)

const int RED = 4;     //LED row 1
const int GREEN = 3;     //LED row 2    
const int BLUE = 2;     //LED row 3

static uint16_t hue = 0; // 0-359
unsigned long previousMillis = 0;
int shift = 0;

void setup() {
  previousMillis = millis() + 5000;
  pinMode(RED, OUTPUT);
  pinMode(GREEN, OUTPUT);
  pinMode(BLUE, OUTPUT);

}

void loop() {
  randomSeed(analogRead(0));
  if (shift==1) {
    for (int hue=0; hue<360; hue++) {
      setLedColorHSV(hue,random(1, 5),random(1, 5));
      delay(random(1, 25));
    }
  }
  if (shift==0) {
    for (int hue=360; hue>0; hue--) {
      setLedColorHSV(hue,random(1, 5),random(1, 5));
      delay(random(1, 25));
    }
  }
  if (((signed long)(millis() - previousMillis)) > 0) {
    previousMillis = millis() + 3000;
    long dice = random(1000);
    if (dice > 900) {
      glowgreen();
      shift=1;
      RGB_color(0,100,0);
    } else if (dice<100) {
      glowblue();
      shift=0;
      RGB_color(100,0,0);
    }
  }
}

void RGB_color(int red_light_value, int green_light_value, int blue_light_value) {
  analogWrite(RED, red_light_value);
  analogWrite(GREEN, green_light_value);
  analogWrite(BLUE, blue_light_value);
}

void setLedColorHSV(int h, double s, double v) {
  //this is the algorithm to convert from RGB to HSV
  double r=0; 
  double g=0; 
  double b=0;

  double hf=h/60.0;

  int i=(int)floor(h/60.0);
  double f = h/60.0 - i;
  double pv = v * (1 - s);
  double qv = v * (1 - s*f);
  double tv = v * (1 - s * (1 - f));

  switch (i)
  {
  case 0: //rojo dominante
    r = v;
    g = tv;
    b = pv;
    break;
  case 1: //verde
    r = qv;
    g = v;
    b = pv;
    break;
  case 2: 
    r = pv;
    g = v;
    b = tv;
    break;
  case 3: //azul
    r = pv;
    g = qv;
    b = v;
    break;
  case 4:
    r = tv;
    g = pv;
    b = v;
    break;
  case 5: //rojo
    r = v;
    g = pv;
    b = qv;
    break;
  }

  //set each component to a integer value between 0 and 255
  int red=constrain((int)255*r,0,255);
  int green=constrain((int)255*g,0,255);
  int blue=constrain((int)255*b,0,255);

  RGB_color(red,green,blue);
}

void glowgreen() {
  for(uint16_t t=0; t<255; t++) {
    RGB_color(0,t,0);
    delay(random(1, 25));
  }
  for(uint16_t t=255; t>0; t--) {
    RGB_color(0,t,0);
    delay(random(1, 25));
  }
}

void glowblue() {
  for(uint16_t t=0; t<255; t++) {
    RGB_color(0,0,t);
    delay(random(1, 25));
  }
  for(uint16_t t=255; t>0; t--) {
    RGB_color(0,0,t);
    delay(random(1, 25));
  }
}