#define BUTTON_PIN A0       // Pin for reading the button state
#define LED_PIN    7        // Pin for the LED output
#define DEBOUNCE_PERIOD 10  // Debounce delay: 10 milliseconds

enum {
  PRESSED = LOW,   // State representing a pressed button
  RELEASED = HIGH  // State representing a released button
};

bool currentButtonState = RELEASED;   // Current state of the button
bool previousButtonState = RELEASED;  // Previous state of the button
bool ledState = false;                // Current state of the LED

void setup() {
  Serial.begin(115200);               // Initialize serial communication at 115200 baud rate
  pinMode(BUTTON_PIN, INPUT_PULLUP);  // Set button pin as input with internal pull-up resistor
  pinMode(LED_PIN, OUTPUT);           // Set LED pin as output
}

void loop() {
  // Main program loop
  // Check for debounced button press and toggle the LED accordingly
  if (instantDebouncer()) {
    ledState = !ledState;             // Toggle the LED state
    digitalWrite(LED_PIN, ledState);  // Update the LED state
  }
}

// Function to debounce the button input
boolean instantDebouncer() {
  static bool isDebouncing = false;             // Flag to indicate ongoing debounce process
  static unsigned long debounceStartTime = 0;   // Timestamp for tracking debounce duration

  bool returnValue = false;               // Variable to hold the debounced button state
  unsigned long currentTime = millis();   // Current time in milliseconds
  bool buttonState = digitalRead(BUTTON_PIN);  // Read the current state of the button

  // Check for state change and reset debounce timer if necessary
  if (buttonState != previousButtonState) {
    debounceStartTime = currentTime;  // Reset debounce timer
  }

  // Debounce the button input
  if (isDebouncing) {
    if (currentTime - debounceStartTime >= DEBOUNCE_PERIOD) {
      isDebouncing = false;  // Reset debounce flag
    }
  } else {
    if (buttonState != currentButtonState) {
      isDebouncing = true;                            // Start debounce process
      currentButtonState = buttonState;               // Update current button state
      returnValue = (currentButtonState == PRESSED);  // Set return value if button is pressed
    }
  }
  previousButtonState = buttonState;  // Update previous button state for the next iteration
  return returnValue;                 // Return the debounced button state
}