// Pin Definitions
const int LED_PIN = 2;     // GPIO 2 for the LED
const int BUTTON_PIN = 4;  // GPIO 4 for the Switch

void setup() {
  // Initialize the LED pin as an output
  pinMode(LED_PIN, OUTPUT);
  
  // Initialize the Switch pin as an input
  // We use INPUT (not INPUT_PULLUP) because you are using an external pull-up resistor
  pinMode(BUTTON_PIN, INPUT);
  
  // Ensure the LED starts in the OFF state
  digitalWrite(LED_PIN, LOW);
}

void loop() {
  // Read the state of the switch
  int buttonState = digitalRead(BUTTON_PIN);

  // With an external pull-up resistor, the pin reads HIGH by default.
  // When the switch is pressed, it connects to GND, pulling the logic to LOW.
  if (buttonState == LOW) {
    
    digitalWrite(LED_PIN, HIGH); // Turn the LED ON
    delay(2000);                 // Keep it ON for 2000 milliseconds (2 seconds)
    digitalWrite(LED_PIN, LOW);  // Turn the LED OFF
    
    // Tiny extra delay to help debounce the switch mechanical bounce
    delay(200);
  }
}