void setup() {
  pinMode(3, OUTPUT);
  pinMode(5, OUTPUT);
}

int i = 127;
int j = 127;
int globalLimit = 255;
int ldr = 0;
int itercnt = 0;
boolean powerDown = false;
boolean powerUp   = false;

void loop() {
  itercnt++;
  ldr = analogRead(A0);

  if (ldr >= 1000 && globalLimit == 255) {
    powerDown = true;
    powerUp   = false;
  } else if (ldr < 1000 && globalLimit == 0) {
    powerDown = false;
    powerUp   = true;
  }

  if (powerDown && globalLimit > 0) {
    // slow shutdown
    itercnt % 8 == 0 && globalLimit--;
  } else if( powerUp && globalLimit < 255 ) {
    // fast start
    globalLimit++;
  }

  delay(50);

  i = limit(i + (random(2) == 0 ? 8 : -8), 16);
  j = limit(j + (random(2) == 0 ? 2 : -2),  2);

  if (ldr > 600) {
    analogWrite(3, j);
    analogWrite(5, i);
  } else { // Simply go dark
    analogWrite(3, 0);
    analogWrite(5, 0);
  }

}

int limit(int i, int within) {
  if (globalLimit < within)
    return 0;

  if (i > (globalLimit - within))
    return globalLimit - within;

  if (i < within)
    return within;

  return i;
}