#define LED_PIN 3
#define POT_PIN A0
#define BTN_PIN 7

bool ledState = false;
bool lastBtn = LOW;

unsigned long lastDebounceTime = 0;
const int debounceDelay = 200; // ms

void setup() {
  Serial.begin(115200);
  pinMode(LED_PIN, OUTPUT);
  pinMode(BTN_PIN, INPUT); // pull-down ngoài
}

void loop() {

  bool btn = digitalRead(BTN_PIN);
  Serial.println(btn);
  // phát hiện cạnh lên + debounce chuẩn
  if (btn == HIGH && lastBtn == LOW && millis() - lastDebounceTime > debounceDelay) {

    ledState = !ledState;

    lastDebounceTime = millis();
  }

  lastBtn = btn;

  if (ledState) {
    int val = analogRead(POT_PIN);
    int pwm = map(val, 0, 1023, 0, 255);
    analogWrite(LED_PIN, pwm);
  } else {
    analogWrite(LED_PIN, 0);
  }
}