#include <LedControl.h>

// MAX7219 pin configuration
const int DIN_PIN = 11;
const int CLK_PIN = 13;
const int CS_PIN = 8;

// Button pin
const int BUTTON_PIN = 7;

// Display configuration
LedControl lc = LedControl(DIN_PIN, CLK_PIN, CS_PIN, 1);

// Stopwatch variables
unsigned long startTime = 0;
unsigned long elapsedTime = 0;
bool isRunning = false;

// Button handling variables
unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 50;
unsigned long pressStartTime = 0;
const unsigned long longPressDuration = 1000;
int lastButtonState = HIGH;

void setup() {
  // Initialize display
  lc.shutdown(0, false);
  lc.setIntensity(0, 8);
  lc.clearDisplay(0);

  // Initialize button
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  
  // Show initial zero
  updateDisplay(0);
}

void loop() {
  handleButton();
  if (isRunning) {
    elapsedTime = millis() - startTime;
    updateDisplay(elapsedTime);
  }
}

void handleButton() {
  int reading = digitalRead(BUTTON_PIN);

  if (reading != lastButtonState) {
    lastDebounceTime = millis();
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (reading != lastButtonState) {
      lastButtonState = reading;

      if (lastButtonState == LOW) {
        pressStartTime = millis();
      } else {
        unsigned long pressDuration = millis() - pressStartTime;
        
        if (pressDuration >= longPressDuration) {
          // Long press - reset
          elapsedTime = 0;
          isRunning = false;
          updateDisplay(0);
        } else {
          // Short press - toggle start/stop
          isRunning = !isRunning;
          if (isRunning) {
            startTime = millis() - elapsedTime;
          }
        }
      }
    }
  }
}

void updateDisplay(unsigned long timeMs) {
  unsigned long totalSeconds = timeMs / 1000;
  int minutes = totalSeconds / 60;
  int seconds = totalSeconds % 60;

  int digits[4] = {
    minutes / 10,        // Minutes tens
    minutes % 10,        // Minutes ones (with colon)
    seconds / 10,        // Seconds tens
    seconds % 10         // Seconds ones
  };

  // Set digits with colon on second position
  for (int i = 0; i < 4; i++) {
    bool dp = (i == 1);  // Show colon on second digit
    lc.setDigit(0, 3 - i, digits[i], dp);
  }
}