#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);  // Alamat I2C dan ukuran LCD (16 kolom, 2 baris)

int startStopButton = 13;   // Pin tombol start/stop
int resetButton = 12;       // Pin tombol reset

volatile boolean timerEnabled = false;
volatile boolean resetRequested = false;
volatile unsigned long startTime = 0;
volatile unsigned long elapsedTime = 0;

void IRAM_ATTR startStopTimer() {
  timerEnabled = !timerEnabled;

  if (timerEnabled) {
    startTime = millis() - elapsedTime;
  }
}

void IRAM_ATTR resetTimer() {
  resetRequested = true;
}

void setup() {
  pinMode(startStopButton, INPUT_PULLUP);
  pinMode(resetButton, INPUT_PULLUP);

  attachInterrupt(digitalPinToInterrupt(startStopButton), startStopTimer, FALLING);
  attachInterrupt(digitalPinToInterrupt(resetButton), resetTimer, FALLING);

  lcd.begin(16, 2);
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Elapsed Time:");
  lcd.setCursor(0, 1);
  lcd.print("0 ms");

  Serial.begin(9600);  // Inisialisasi Serial Monitor
  Serial.println("Stopwatch started");
}

void loop() {
  if (timerEnabled) {
    unsigned long currentTime = millis();
    elapsedTime = currentTime - startTime;

    lcd.setCursor(0, 1);
    lcd.print(elapsedTime);
    lcd.print(" ms");

    Serial.print("Elapsed Time: ");
    Serial.print(elapsedTime);
    Serial.println(" ms");
  }

  if (resetRequested && !timerEnabled) {
    resetRequested = false;
    elapsedTime = 0;
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Elapsed Time:");
    lcd.setCursor(0, 1);
    lcd.print("0 ms");

    Serial.println("Timer reset");
  }
}