#define STATE_OFF 0
#define STATE_DIM 1
#define STATE_NORMAL 2
#define STATE_ALERT 3
int count = STATE_OFF;

void setup() {
pinMode(13, INPUT_PULLUP);
pinMode(12, OUTPUT);
pinMode(A0, INPUT);
}

void loop() {
  checkTransitions();
  executeState();
}
boolean isUp = true;
boolean wasUp = true;

void checkTransitions() {
  isUp = digitalRead(13);

  if (wasUp != isUp) {
    delay(20);
    if (!isUp) {
      int nextState = count + 1;
      if (nextState > STATE_ALERT) {
        nextState = STATE_OFF;
      }
      changeState(nextState);
    }
  }
  wasUp = isUp;
}

void changeState(int newState) {

  if (newState < STATE_OFF || newState > STATE_ALERT) {
    newState = STATE_OFF;
  }
  count = newState;
}

void executeState() {
int save = analogRead(A0);
  if(count == STATE_OFF){
  if(save > 400){
  analogWrite(12, 255);
}else{ 
  analogWrite(12, 0);
} 
}else if (count == STATE_DIM){
  if(save > 400){
  analogWrite(12, 255);
}else{ 
  analogWrite(12, 0);
}
}else if (count == STATE_NORMAL){
  if (save > 400){ 
  analogWrite(12, 255);
}else{ 
  analogWrite(12, 255);
} 
}else if (count == STATE_ALERT){ 
  digitalWrite(12, HIGH);
  delay(100);
  digitalWrite(12, LOW); 
  delay(100);
}
}