/*
 LED Fading mit NodeMCU v 1.0
*/

class RgbLed {
  int ledRedPin;
  int ledGreenPin;
  int ledBluePin;

  byte ledRedIntensity;
  byte ledGreenIntensity;
  byte ledBlueIntensity;

  byte ledRedIntensityTo;
  byte ledGreenIntensityTo;
  byte ledBlueIntensityTo;

  long durationLeft;
  long previousMillis;

  public:
  RgbLed(int redPin, int greenPin, int bluePin)
  {
    ledRedPin = redPin;
    ledGreenPin = greenPin;
    ledBluePin = bluePin;

    pinMode(ledRedPin, OUTPUT);
    pinMode(ledGreenPin, OUTPUT);
    pinMode(ledBluePin, OUTPUT);

    ledRedIntensity = 0;
    ledGreenIntensity = 0;
    ledBlueIntensity = 0;

    ledRedIntensityTo = ledRedIntensity;
    ledGreenIntensityTo = ledGreenIntensity;
    ledBlueIntensityTo = ledBlueIntensity;

    durationLeft = 0;
    previousMillis = 0;
  }

  public:
  void ChangeColor(int redIntesity, int greenIntensity, int blueIntensity, long duration)
  {
    if (ledRedIntensityTo == ledRedIntensity && ledGreenIntensityTo == ledGreenIntensity && ledBlueIntensityTo == ledBlueIntensity
    && ledRedIntensity != redIntesity && ledGreenIntensity != greenIntensity && ledBlueIntensity != blueIntensity) {
      durationLeft = duration;
      ledRedIntensityTo = ledRedIntensity;
      ledGreenIntensityTo = ledGreenIntensity;
      ledBlueIntensityTo = ledBlueIntensity;
    }
  }

  public:
  void Update(long currentMillis)
  {
    if (ledRedIntensityTo != ledRedIntensity && ledGreenIntensityTo != ledGreenIntensity && ledBlueIntensityTo != ledBlueIntensity) {
      ledRedIntensity = lerp(ledRedIntensity, ledRedIntensityTo, previousMillis, previousMillis + durationLeft, currentMillis);
      ledGreenIntensity = lerp(ledGreenIntensity, ledGreenIntensityTo, previousMillis, previousMillis + durationLeft, currentMillis);
      ledBlueIntensity = lerp(ledBlueIntensity, ledBlueIntensityTo, previousMillis, previousMillis + durationLeft, currentMillis);
      UpdateLEDs();
    }
    durationLeft = durationLeft - (currentMillis - previousMillis);
    previousMillis = currentMillis;
  }

  byte lerp(byte intensityStart, byte intensityEnd, long timeStart, long timeEnd, long timeCurrent) {
    return ( ( timeCurrent - timeStart )( intensityEnd - intensityStart) / ( timeEnd - timeStart) ) + intensityStart;
  }

  void UpdateLEDs() {
    digitalWrite(ledRedPin, ledRedIntensity);
    digitalWrite(ledGreenPin, ledGreenIntensity);
    digitalWrite(ledBluePin, ledBlueIntensity);
  }
};


RgbLed ledStripe(5, 4, 0);

void setup() {
}

void loop()
{
  ledStripe.ChangeColor(30, 200, 255, 1000);
  ledStripe.Update(millis());
}