const int kPinPot = A0;
const int kPinLed = 9;
const int kButtonToggle = 2;
const int kButtonBrightness = 3; 

int ledState = LOW; 
int previousButtonStateToggle = HIGH;
int previousButtonStateBrightness = HIGH;
int ledBrightness = 0;

void setup() {
  // put your setup code here, to run once:
  pinMode(kPinPot, INPUT);
  pinMode(kPinLed, OUTPUT);
  pinMode(kButtonToggle, INPUT_PULLUP);
  pinMode(kButtonBrightness, INPUT_PULLUP);
  analogWrite(kPinLed, 0);
}

void loop() {
  // put your main code here, to run repeatedly:
  int sensorValue = analogRead(kPinPot);
  int maxBrightness = map(sensorValue, 0, 1023, 0, 255);
  int buttonStateToggle = digitalRead(kButtonToggle);
  if (buttonStateToggle == LOW && previousButtonStateToggle == HIGH) {
    ledState = !ledState;
    if (ledState == HIGH) {
      analogWrite(kPinLed, ledBrightness);
    } else{
      analogWrite(kPinLed, 0);
    }
    delay(200);
  }
  previousButtonStateToggle = buttonStateToggle;
  int buttonStateBrightness = digitalRead(kButtonBrightness);
  if (buttonStateBrightness == LOW && previousButtonStateBrightness == HIGH && ledState == HIGH) 
  {
    ledBrightness = constrain(ledBrightness + 10, 0, maxBrightness);
    analogWrite(kPinLed, ledBrightness);
    delay(200);
  }
  previousButtonStateBrightness = buttonStateBrightness;
}