#define STATE_OFF 0
#define STATE_DIM 1
#define STATE_NORMAL 2
#define STATE_ALERT 3

const int button = 2;
const int photo = A0;
const int led = 9;

int currentState == STATE_OFF;
boolean lastButtonState = true; 

void setup() {
  pinMode(button, INPUT);
  pinMode(led, OUTPUT);
}

void loop() {
  checkTransitions();
  executeState();
  delay(100);
}

void changeState(int newState) {
  currentState = newState;
}

void executeState() {
  switch(currentState) {
    case STATE_OFF:
      analogWrite(led, 0);
      break;
    case STATE_DIM:
      analogWrite(led, 64); 
      break;
    case STATE_NORMAL:
      analogWrite(led, 255); 
      break;
    case STATE_ALERT:
      if (millis() % 400 < 200) {
        analogWrite(led, 255);
      } else {
        analogWrite(led, 0);
      }
      break;
  }
}

void checkTransitions() {
  boolean buttonState = digitalRead(button);
  if (buttonState == LOW && lastButtonState == HIGH) {
    delay(50); 
    currentState = (currentState + 1) % 4;
  }
  // lastButtonState = buttonState;
  
  int lightLevel = analogWrite(photo);
  if (lightLevel < 500 && currentState == STATE_OFF) {
    currentState = STATE_DIM;
  }
}