const int redPin = 11;
const int greenPin = 10;
const int bluePin = 9;

const int buttonRedDown = 2;
const int buttonGreenDown = 3;
const int buttonBlueDown = 4;
const int buttonRedUp = 5;
const int buttonGreenUp = 6;
const int buttonBlueUp = 7;

int lastButtonRD = LOW;
int currButtonRD = LOW;
int lastButtonRU = LOW;
int currButtonRU = LOW;
int lastButtonGD = LOW;
int currButtonGD = LOW;
int lastButtonGU = LOW;
int currButtonGU = LOW;
int lastButtonBD = LOW;
int currButtonBD = LOW;
int lastButtonBU = LOW;
int currButtonBU = LOW;

int redValue = 255;
int greenValue = 255;
int blueValue = 255;

const int step = 50;


int debounce (int& last, int button)
{
  int current = digitalRead(button);
  if(last != current)
  {
    delay(5);
    current = digitalRead(button);
  }
  return current;
}


void manageButton(int buttonUp, int buttonDown, int& lastButtonUp, int& lastButtonDown, 
                  int& currButtonUp, int& currButtonDown, int& value, int colorPin)
{
  currButtonUp = debounce(lastButtonUp, buttonUp);
  if(lastButtonUp == HIGH && currButtonUp == LOW)
  {
    value = max(value - step, 5);
    analogWrite(colorPin, value);
  }

  currButtonDown = debounce(lastButtonDown, buttonDown);
  if(lastButtonDown == HIGH && currButtonDown == LOW)
  {
    value = min(value + step, 255);
    analogWrite(colorPin, value);
  }

  lastButtonUp = currButtonUp;
  lastButtonDown = currButtonDown;
}

void setup() {
  pinMode(redPin, OUTPUT);
  digitalWrite(redPin, HIGH);
  pinMode(greenPin, OUTPUT);
  digitalWrite(greenPin, HIGH);
  pinMode(bluePin, OUTPUT);
  digitalWrite(bluePin, HIGH);

  pinMode(buttonRedDown, INPUT_PULLUP);
  pinMode(buttonGreenDown, INPUT_PULLUP);
  pinMode(buttonBlueDown, INPUT_PULLUP);
  pinMode(buttonRedUp, INPUT_PULLUP);
  pinMode(buttonGreenUp, INPUT_PULLUP);
  pinMode(buttonBlueUp, INPUT_PULLUP);
}

void loop() {

  manageButton(buttonRedUp, buttonRedDown, lastButtonRU, lastButtonRD, currButtonRU,
              currButtonRD, redValue, redPin);
  manageButton(buttonGreenUp, buttonGreenDown, lastButtonGU, lastButtonGD, currButtonGU, 
              currButtonGD, greenValue, greenPin);
  manageButton(buttonBlueUp, buttonBlueDown, lastButtonBU, lastButtonBD, currButtonBU, 
              currButtonBD, blueValue, bluePin);

}