// Define the pins for the RGB LED (common anode)
const int redPin = 9;
const int greenPin = 10;
const int bluePin = 11;

// Variables to store the current RGB values
int redValue = 0;
int greenValue = 0;
int blueValue = 0;

// Time interval between color transitions (in milliseconds)
const int transitionInterval = 10;

void setup() {
  // Initialize PWM pins for the RGB LED
  pinMode(redPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
  pinMode(bluePin, OUTPUT);
}

void loop() {
  // Smoothly transition through all hues of the color wheel
  for (int hue = 0; hue < 360; hue++) {
    // Calculate RGB values based on current hue
    calculateRGBfromHue(hue);

    // Update the RGB LED with the new values
    analogWrite(redPin, redValue);
    analogWrite(greenPin, greenValue);
    analogWrite(bluePin, blueValue);

    // Delay for smooth transition
    delay(transitionInterval);
  }
}

// Function to calculate RGB values from hue
void calculateRGBfromHue(int hue) {
  float saturation = 1.0; // Saturation and value are set to 1 for full intensity
  float value = 1.0;
  
  int i = int(hue / 60.0);
  float f = (hue / 60.0) - i;
  float p = value * (1.0 - saturation);
  float q = value * (1.0 - saturation * f);
  float t = value * (1.0 - saturation * (1.0 - f));
  
  switch(i) {
    case 0:
      redValue = int(value * 255);
      greenValue = int(t * 255);
      blueValue = int(p * 255);
      break;
    case 1:
      redValue = int(q * 255);
      greenValue = int(value * 255);
      blueValue = int(p * 255);
      break;
    case 2:
      redValue = int(p * 255);
      greenValue = int(value * 255);
      blueValue = int(t * 255);
      break;
    case 3:
      redValue = int(p * 255);
      greenValue = int(q * 255);
      blueValue = int(value * 255);
      break;
    case 4:
      redValue = int(t * 255);
      greenValue = int(p * 255);
      blueValue = int(value * 255);
      break;
    default:
      redValue = int(value * 255);
      greenValue = int(p * 255);
      blueValue = int(q * 255);
      break;
  }
}