#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16,2);

bool firstState = true, firstState2 = true, firstState3 = true;

int minuty, sekundy, page;
int long currentTime;

void setup() {
  lcd.init();
  lcd.backlight();
  Serial.begin(9600);

  DDRB &= ~(0b111<<0);
  PORTB |= 0b111<<0;

  lcd.print("0:0");
  lcd.setCursor(0,1);
  lcd.print("Minuty ");
  lcd.home();
}

void loop() {
  if(millis() >= currentTime){
    sekundy--;
    if(sekundy <= 0){
      sekundy = 0;
      minuty--;
    }
    if(minuty <= 0) minuty = 0;

    if(minuty > 0 && sekundy == 0) sekundy = 59;

    lcd.home();
    lcd.print(String(minuty)+":"+String(sekundy)+" ");

    currentTime += 1000;
  }

  if( (PINB&(0b1<<2)) == 0 && firstState3 == true){
    firstState3 = false;
    page = !page;
    if(page == 0){
      lcd.setCursor(0,1);
      lcd.print("Minuty ");
    }
    else{
      lcd.setCursor(0,1);
      lcd.print("Sekundy");
    }
  }

  if( (PINB&(0b1<<0)) == 0 && firstState == true){
    firstState = false;
    lcd.setCursor(0,0);
    lcd.print("       ");
    lcd.home();
    if(page == 0){
      lcd.home();
      minuty++;
      if(minuty > 59) minuty = 0;
      lcd.print(String(minuty)+":"+String(sekundy));
    }

    else{
      lcd.home();
      sekundy++;
      if(sekundy > 59){
        sekundy = 0;
        minuty++;
      }
        
      lcd.print(String(minuty)+":"+String(sekundy));
    }
  }


  if( (PINB&(0b1<<1)) == 0 && firstState2 == true){
    lcd.setCursor(0,0);
    lcd.print("       ");
    lcd.home();
    firstState2 = false;
    if(page == 0){
      lcd.home();
      minuty--;
      if(minuty < 0) minuty = 0;
      lcd.print(String(minuty)+":"+String(sekundy));
    }

    else{
      lcd.home();
      sekundy--;
      if(sekundy < 0) sekundy = 0;
      lcd.print(String(minuty)+":"+String(sekundy));
    }
    
  }


  if( (PINB&(0b1<<2)) != 0 && firstState3 != true)
    firstState3 = true;
  if( (PINB&(0b1<<0)) != 0 && firstState != true)
    firstState = true;
  if( (PINB&(0b1<<1)) != 0 && firstState2 != true)
    firstState2 = true;

}