#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,20,4);
#define buzzer 6

int waktu;
int tombol1 = 2;
int tombol2 = 3;
int tombol3 = 4;
int tombol4 = 5;
bool tombol1_push;
bool tombol2_push;
bool tombol3_push;
bool tombol4_push;
int startstop;

int alarm;
int menit;
int detik;

void setup() {
  // put your setup code here, to run once:
  digitalWrite(buzzer, LOW);
  alarm = 0;
  startstop = 0;
  waktu = 0;
  pinMode(tombol1, INPUT_PULLUP);
  pinMode(tombol2, INPUT_PULLUP);
  pinMode(tombol3, INPUT_PULLUP);
  pinMode(tombol4, INPUT_PULLUP);
  pinMode(buzzer, OUTPUT);
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0,0);
  lcd.print("Timer Alarm");
  lcd.setCursor(10,2);
  lcd.print("Menit");
  lcd.setCursor(10,3);
  lcd.print("Detik");
}

void loop() {
  // put your main code here, to run repeatedly:
  tombol1_push = digitalRead(tombol1);
  tombol2_push = digitalRead(tombol2);
  tombol3_push = digitalRead(tombol3);
  tombol4_push = digitalRead(tombol3);
  if (tombol2_push == 0){
    if (startstop == 0){
      startstop = 1;
    }
    else if (startstop == 1){
      startstop = 0;
    }
    delay(1000);
  }

  if (tombol1_push == 0){
    if (waktu >= 3600){
      } else{
      if (startstop == 0){
      delay(250);
      waktu = waktu + 10;
      }
    }
  }
  if (tombol4_push == 0){
    if (waktu < 10){
      } else{
      if (startstop == 0){
      waktu = waktu - 10;
      delay(250);
      }
    }
  }
  if (waktu != 0){
    if (startstop == 1){
      waktu = waktu - 1;
      delay(1000);
      if (waktu == 0){
        if (alarm == 0){
          alarm = 1;
        }
      }
    }
  }

  if (tombol3_push == 0){
    alarm = 0;
    startstop = 0;
    noTone(buzzer);
  }
  if (alarm == 1){
    tone(buzzer,4000);
    delay(250);
    noTone(buzzer);
  }
  menit = waktu / 60;
  detik = waktu - (menit*60);
  if (menit >= 10){
    lcd.setCursor(1,2);
    lcd.print(menit);
  } else {
    lcd.setCursor(1,2);
    lcd.print("0");
    lcd.setCursor(2,2);
    lcd.print(menit);
  }
  
  if (detik >= 10){
    lcd.setCursor(1,3);
    lcd.print(detik);
  } else {
    lcd.setCursor(1,3);
    lcd.print("0");
    lcd.setCursor(2,3);
    lcd.print(detik);
  }
}