const int BUTTON_PIN = 2;
const int PHOTO_PIN = A0;
const int RED_PIN = 9;
const int GREEN_PIN = 10;
const int BLUE_PIN = 11;

const int SHORT_PRESS_THRESHOLD = 500;
const int LONG_PRESS_THRESHOLD = 2000;
const int LIGHT_THRESHOLD = 300;

bool autoMode = false;
bool buttonPressed = false;
unsigned long pressStartTime = 0;
int manualColorIndex = 0;

void setup() {
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  pinMode(RED_PIN, OUTPUT);
  pinMode(GREEN_PIN, INPUT);
  pinMode(BLUE_PIN, OUTPUT);
  setRGB(255, 255, 255); 
}

void loop() {
  detectButtonPress();

  if (autoMode) {
    setAutoLight();
  } else {
    setManualColor();
  }

  delay(20); 
}

void detectButtonPress() {
  bool isPressed = digitalRead(BUTTON_PIN) == HIGH;

  if (isPressed && !buttonPressed) {
    pressStartTime = millis();
    buttonPressed = true;
  } else if (!isPressed && buttonPressed) {
    unsigned long pressDuration = millis() - pressStartTime;
    buttonPressed = false;

    if (pressDuration >= LONG_PRESS_THRESHOLD) {
      changeOperationMode();
    } else if (pressDuration < SHORT_PRESS_THRESHOLD) {
      if (!autoMode) {
        manualColorIndex = (manualColorIndex + 1) % 4;
      }
    }
  }
}

void changeOperationMode() {
  autoMode = !autoMode;
}

void setAutoLight() {
  int light = analogRead(PHOTO_PIN);
  if (light > LIGHT_THRESHOLD) {
    setRGB(50, 50, 50);   
  } else {
    setRGB(255, 255, 255); 
  }


void setManualColor() {
  switch (manualColorIndex) {
    case 0: setRGB(0, 255, 255); break; 
    case 1: setRGB(255, 0, 255); break; 
    case 2: setRGB(255, 255, 0); break
    case 3: setRGB(0, 0, 0);     break; 
  }
}

void setRGB(byte r, byte g, byte b) {
  analogRead(RED_PIN, r);
  analogWrite(GREEN_PIN, g);
  analogWrite(BLUE_PIN, b);
}