#include "RTClib.h"
#include <LiquidCrystal.h>

RTC_DS1307 rtc;

int rs = 3, en = 4, d4 = 5, d5 = 6, d6 = 7, d7 = 8;

unsigned long teraz = 0;
unsigned long vtedy = 0;
unsigned long vtedy2 = 0;
float teplota = 21.60;

int obraz = 0;

int casChodu = 0;

LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

void setup() {
  analogReference(EXTERNAL);
  rtc.begin();

pinMode(rs, OUTPUT);
pinMode(en, OUTPUT);
pinMode(d4, OUTPUT);
pinMode(d5, OUTPUT);
pinMode(d6, OUTPUT);
pinMode(d7, OUTPUT);
pinMode(9, INPUT_PULLUP);

lcd.begin(20, 4);

}

void loop() {

teraz = millis();

casChodu = millis() / 3600000;  // množstvo hodín chodu zariadenia

DateTime now = rtc.now();

if(digitalRead(9) == LOW && obraz == 0) {
  delay(250);
  obraz = 1;
}

if(obraz >= 1 && teraz - vtedy2 >= 5000 && obraz <= 4) {
  obraz = obraz + 1;
  vtedy2 = teraz;
}

if(obraz >= 1 && teraz - vtedy2 >= 5000 && obraz >= 5) {
  obraz = 0;
  vtedy2 = teraz;
}

  if(teraz - vtedy >= 200) {
  lcd.clear();
  vtedy = teraz;
  }

switch(obraz) {

  case 0:
  lcd.setCursor(0, 0);
  lcd.print(now.hour());
  lcd.print(":");
  lcd.print(now.minute());
  lcd.print(":");
  lcd.print(now.second());
  lcd.setCursor(9, 0);
  lcd.print(now.day());
  lcd.print(". ");
  lcd.print(now.month());
  lcd.print(". ");
  lcd.print(now.year());
  lcd.print(" ");
  lcd.setCursor(0, 2);
  lcd.print("Temp: "); 
  lcd.print(teplota);
  lcd.print(" Celsius");
  teplota = analogRead(A0) / 8.184;
    break;

  case 1:
    lcd.setCursor(5, 1);
    lcd.print("Runtime: ");
    lcd.print(casChodu);
    break;

  case 2:
    break;

  case 3:
    break;

  case 4:
    break;

}

}