#define LED_PIN 2
#define BUTTON_PIN 13

#define MODE_ON 1
#define MODE_WEAK 2
#define MODE_OFF 3

byte ledModes[] = {MODE_ON, MODE_WEAK, MODE_OFF};
byte ledModeCount;
byte currentLedMode;
byte delayMs;

void setup() {
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUTTON_PIN, INPUT);

  ledModeCount = sizeof(ledModes);
  currentLedMode = MODE_OFF;
  delayMs = 0;
}

void loop() {
  if (digitalRead(BUTTON_PIN) == LOW) {
    delay(20);

    if (digitalRead(BUTTON_PIN) == LOW) {
      currentLedMode = (currentLedMode + 1) % ledModeCount;
    }

    while (digitalRead(BUTTON_PIN) == LOW);
    delay(20);
    while (digitalRead(BUTTON_PIN) == LOW);
  }

  applyLedMode();
}

void applyLedMode() {
  switch (currentLedMode) {
    case MODE_ON:
      digitalWrite(LED_PIN, HIGH);
      break;
    case MODE_WEAK:
      digitalWrite(LED_PIN, HIGH);
      delayMicroseconds(500);
      digitalWrite(LED_PIN, LOW);
      delay(10);
      break;
    case MODE_OFF:
      digitalWrite(LED_PIN, LOW);
      break;
  }
}