#include <LiquidCrystal_I2C.h>


#define SDA A4
#define SCL A5
#define BUZZER 4
#define TLACITKO 5

LiquidCrystal_I2C lcd(0x27, 16, 2);

byte customChar[8] = {
	0b10001,
	0b10001,
	0b11011,
	0b01010,
	0b01110,
	0b00100,
	0b01110,
	0b10001
};

int cislo = 10;
bool stav = false;

int buttonState = LOW;
int lastButtonState = LOW;
unsigned long lastDebounceTime = 0;
uint8_t debounceInterval = 50;

unsigned long previousMillis = 0;

void setup() {
  pinMode(TLACITKO, INPUT);
  lcd.init();
  lcd.backlight();

  lcd.createChar(0, customChar); // create a new custom character

  lcd.setCursor(2, 0); // move cursor to (2, 0)
  lcd.write((byte)0);  // print the custom char at (2, 0)


  lcd.setCursor(5, 1);
  lcd.print(cislo);
}

void loop() {

  int reading = digitalRead(TLACITKO);

  if(millis() - previousMillis >= 1000 && stav){
    previousMillis = millis();
    lcd.print(cislo--);
    if(cislo == 0)
    {
      stav = false;
      tone(BUZZER, 262, 1000);
    }
  }   

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

  if((millis() - lastDebounceTime) >= debounceInterval){
    if(reading != buttonState) {
      if(buttonState == HIGH && !stav){
        stav = true;
        cislo = 10;
      }
    }
    buttonState = reading;
  }
}