#define RED_PIN   9
#define GREEN_PIN 10
#define BLUE_PIN  11
#define BUTTON    2

int colorState = 0;
bool lastButton = HIGH;

void setup() {
  pinMode(RED_PIN, OUTPUT);
  pinMode(GREEN_PIN, OUTPUT);
  pinMode(BLUE_PIN, OUTPUT);

  pinMode(BUTTON, INPUT_PULLUP);

  // RGB OFF initially
  allOff();
}

void loop() {
  bool currentButton = digitalRead(BUTTON);

  // Button press detected
  if (lastButton == HIGH && currentButton == LOW) {
    colorState++;
    if (colorState > 4) colorState = 0;
    delay(200); // debounce
  }

  lastButton = currentButton;

  switch (colorState) {
    case 0: // OFF
      allOff();
      break;

    case 1: // RED
      redOn();
      break;

    case 2: // GREEN
      greenOn();
      break;

    case 3: // BLUE
      blueOn();
      break;

    case 4: // WHITE
      whiteOn();
      break;
  }
}

// ---------- FUNCTIONS ----------

void allOff() {
  digitalWrite(RED_PIN, HIGH);
  digitalWrite(GREEN_PIN, HIGH);
  digitalWrite(BLUE_PIN, HIGH);
}

void redOn() {
  digitalWrite(RED_PIN, LOW);
  digitalWrite(GREEN_PIN, HIGH);
  digitalWrite(BLUE_PIN, HIGH);
}

void greenOn() {
  digitalWrite(RED_PIN, HIGH);
  digitalWrite(GREEN_PIN, LOW);
  digitalWrite(BLUE_PIN, HIGH);
}

void blueOn() {
  digitalWrite(RED_PIN, HIGH);
  digitalWrite(GREEN_PIN, HIGH);
  digitalWrite(BLUE_PIN, LOW);
}

void whiteOn() {
  digitalWrite(RED_PIN, LOW);
  digitalWrite(GREEN_PIN, LOW);
  digitalWrite(BLUE_PIN, LOW);
}