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

LiquidCrystal_I2C lcd(0x27, 16, 2);

// Time variables
int hours = 0, minutes = 0, seconds = 0;

// Alarm variables
int alarmHour = 0, alarmMinute = 0;
bool alarmSet = false;

// Pins
const int btnHour = 2;
const int btnMin  = 3;
const int btnAlarm = 4;
const int buzzer  = 8;

unsigned long lastTick = 0;

void setup() {
  lcd.init();
  lcd.backlight();

  pinMode(btnHour,  INPUT_PULLUP);
  pinMode(btnMin,   INPUT_PULLUP);
  pinMode(btnAlarm, INPUT_PULLUP);
  pinMode(buzzer,   OUTPUT);

  lcd.setCursor(0, 0);
  lcd.print("  Digital Clock ");
  delay(1500);
  lcd.clear();
}

void loop() {
  // Tick every second
  if (millis() - lastTick >= 1000) {
    lastTick = millis();
    seconds++;
    if (seconds == 60) { seconds = 0; minutes++; }
    if (minutes == 60) { minutes = 0; hours++;   }
    if (hours   == 24) { hours = 0;               }
  }

  // Button: Set Hour
  if (digitalRead(btnHour) == LOW) {
    hours = (hours + 1) % 24;
    delay(300);
  }

  // Button: Set Minute
  if (digitalRead(btnMin) == LOW) {
    minutes = (minutes + 1) % 60;
    delay(300);
  }

  // Button: Toggle Alarm (cycles through alarm times)
  if (digitalRead(btnAlarm) == LOW) {
    alarmMinute = (alarmMinute + 1) % 60;
    if (alarmMinute == 0) alarmHour = (alarmHour + 1) % 24;
    alarmSet = true;
    delay(300);
  }

  // Check alarm
  if (alarmSet && hours == alarmHour && minutes == alarmMinute && seconds == 0) {
    tone(buzzer, 1000, 2000); // Beep for 2 seconds
  }

  // Display time on row 1
  lcd.setCursor(0, 0);
  lcd.print("Time: ");
  printTwoDigits(hours);
  lcd.print(":");
  printTwoDigits(minutes);
  lcd.print(":");
  printTwoDigits(seconds);

  // Display alarm on row 2
  lcd.setCursor(0, 1);
  if (alarmSet) {
    lcd.print("Alarm:");
    printTwoDigits(alarmHour);
    lcd.print(":");
    printTwoDigits(alarmMinute);
    lcd.print("  ON ");
  } else {
    lcd.print("Alarm: --:-- OFF");
  }

  delay(100);
}

void printTwoDigits(int num) {
  if (num < 10) lcd.print("0");
  lcd.print(num);
}