#include <Bounce2.h> // https://github.com/thomasfredericks/Bounce2

// WE WILL attach() THE Bounce INSTANCE TO THE FOLLOWING PIN IN setup()
const byte buttonUP_PIN = 4;
const byte buttonDOWN_PIN = 3;

#define LED_PIN 10

int brightness = 0;

// INSTANTIATE A Bounce OBJECT.
Bounce buttonUP = Bounce();
Bounce buttonDOWN = Bounce();

void setup() {
  Serial.begin(9600);
  buttonUP.attach(buttonUP_PIN, INPUT_PULLUP);
  buttonDOWN.attach(buttonDOWN_PIN, INPUT_PULLUP);

  buttonUP.interval(5); // interval in ms
  buttonDOWN.interval(5); // interval in ms

  pinMode(LED_PIN, OUTPUT);
}

void loop() {
  // Update the Bounce instance (YOU MUST DO THIS EVERY LOOP)
  buttonUP.update();
  buttonDOWN.update();

  // GET THE STATE WITH <Bounce.read()>
  int debouncedStateUP = buttonUP.read();
  int debouncedStateDOWN = buttonDOWN.read();

  // <Bounce>.duration() RETURNS THE TIME IN MILLISECONDS THE CURRENT STATE HAS BEEN HELD.
  // SO WE CHECK IF THE STATE IS LOW AND IF IT HAS BEEN LOW FOR MORE THAN 200 MS.
  if ((debouncedStateUP == LOW) && (buttonUP.currentDuration() > 200))
  {
    brightness++;

    if (brightness > 255)
    {
      brightness = 255;
    }
    analogWrite(LED_PIN, brightness);
    Serial.println(brightness);
  }

  if ((debouncedStateDOWN == LOW) && (buttonDOWN.currentDuration() > 200))
  {
    brightness--;

    if (brightness < 0)
    {
      brightness = 0;
    }
    analogWrite(LED_PIN, brightness);
    Serial.println(brightness);
  }

}