const int kPinPot1 = A0;
const int kPinPot2 = A1;
const int kPinPot3 = A2;
const int kPinLed_R = 6;
const int kPinLed_G = 10;
const int kPinLed_B = 11;

const int kPinGasButton = 2;
const int kPinBrakeButton = 3;
const int kPinSpeedLed = 9;

int speed = 0;
const int maxSpeed = 255;
const int minSpeed = 0;
const int speedIncrement = 5;

void setup() {
  pinMode(kPinLed_R, OUTPUT);
  pinMode(kPinLed_G, OUTPUT);
  pinMode(kPinLed_B, OUTPUT);
  pinMode(kPinGasButton, INPUT_PULLUP);
  pinMode(kPinBrakeButton, INPUT_PULLUP);
  pinMode(kPinSpeedLed, OUTPUT);
}

void loop() {
  int potValue;
  int ledValue;

  potValue = analogRead(kPinPot1);
  ledValue = map(potValue, 0, 1023, 0, 255);
  analogWrite(kPinLed_R, ledValue);

  potValue = analogRead(kPinPot2);
  ledValue = map(potValue, 0, 1023, 0, 255);
  analogWrite(kPinLed_G, ledValue);

  potValue = analogRead(kPinPot3);
  ledValue = map(potValue, 0, 1023, 0, 255);
  analogWrite(kPinLed_B, ledValue);

  if (digitalRead(kPinGasButton) == LOW) {
    speed += speedIncrement;
    if (speed > maxSpeed) {
      speed = maxSpeed;
    }
  }

  if (digitalRead(kPinBrakeButton) == LOW) {
    speed -= speedIncrement;
    if (speed < minSpeed) {
      speed = minSpeed;
    }
  }

  analogWrite(kPinSpeedLed, speed);

  delay(100);
}