// Pin definitions
const int whiteLED = 9;   // PWM pin for White LED
const int yellowLED = 6;  // PWM pin for Yellow LED
const int redLED = 5;     // PWM pin for Red LED
const int blueLED = 3;    // PWM pin for Blue LED

void setup() {
  pinMode(whiteLED, OUTPUT);
  pinMode(yellowLED, OUTPUT);
  pinMode(redLED, OUTPUT);
  pinMode(blueLED, OUTPUT);
}

void loop() {
  unsigned long currentTime = millis() % 90000; // Loop time is 90 seconds

  // White LED: Fade in and out
  controlLED(whiteLED, 255, 0, 0, 25000, currentTime);     // 0-25 sec: Fade out
  controlLED(whiteLED, 0, 255, 65000, 90000, currentTime); // 65-90 sec: Fade in

  // Yellow LED: Fade in and out
  controlLED(yellowLED, 0, 255, 7500, 17500, currentTime);  // 7.5-17.5 sec: Fade in
  controlLED(yellowLED, 255, 0, 17500, 27500, currentTime); // 17.5-27.5 sec: Fade out
  controlLED(yellowLED, 0, 255, 60000, 70000, currentTime); // 60-70 sec: Fade in
  controlLED(yellowLED, 255, 0, 70000, 80000, currentTime); // 70-80 sec: Fade out

  // Red LED: Fade in and out
  controlLED(redLED, 0, 255, 20000, 27500, currentTime);    // 20-27.5 sec: Fade in
  controlLED(redLED, 255, 0, 27500, 35000, currentTime);    // 27.5-35 sec: Fade out
  controlLED(redLED, 0, 255, 55000, 62500, currentTime);    // 55-62.5 sec: Fade in
  controlLED(redLED, 255, 0, 62500, 70000, currentTime);    // 62.5-70 sec: Fade out

  // Blue LED: Fade in, stay, and fade out
  controlLED(blueLED, 0, 255, 27500, 35000, currentTime);   // 27.5-35 sec: Fade in
  controlLED(blueLED, 255, 255, 35000, 55000, currentTime); // 35-55 sec: Stay at full brightness
  controlLED(blueLED, 255, 0, 55000, 62500, currentTime);   // 55-62.5 sec: Fade out
}

// Function to control LED brightness
void controlLED(int pin, int startBrightness, int endBrightness, unsigned long startTime, unsigned long endTime, unsigned long currentTime) {
  // Check if the current time is within the active period for this LED's fade cycle
  if (currentTime >= startTime && currentTime <= endTime) {
    unsigned long duration = endTime - startTime;
    // Map the current time to the appropriate brightness level based on start and end brightness
    int brightness = map(currentTime - startTime, 0, duration, startBrightness, endBrightness);

    // Ensure full fade-out in the last few milliseconds of the cycle, if fading out
    // IF LEDS REMAIN SLIGHTLY ON AT THE END OF THE CYCLE, INCREASE THE 5MS THRESHOLD (E.G., TO 10MS)
    if ((endTime - currentTime) < 5 && endBrightness == 0) {
      brightness = 0; // Force brightness to 0 to fully turn off the LED
    }

    // Apply the calculated brightness to the LED
    analogWrite(pin, brightness);
  }
}