#include <LiquidCrystal_I2C.h> // Knižnica pre LCD displej

// Priradenie pinov
LiquidCrystal_I2C lcd(0x27, 16, 2);
const int Buzzer = 6;
const int TimeUp = 2; // Tlačidlo 1 v pine 2
const int TimeDown = 3; // Tlačidlo 2 v pine 3
const int SettingValue = 4; // Tlačidlo 3 a 4 v pine 4
const int ModeSwitch = 5; // Tlačidlo 4 v pine 5

// Vytvorenie premenných
int hours = 0;
int minutes = 0;
int seconds = 0;
int alarmHours = 0;
int alarmMinutes = 0;
int alarmSeconds = 0; // Nastavenie času budíka na 0
int Mode = 1;
int settingValue = 0;
bool SettingTime = false;
bool SettingTimeUp = false;
bool SettingTimeDown = false;
bool alarmIsActive = false;

// Počiatočná inicilizácia
void setup() {
  pinMode(TimeUp, INPUT_PULLUP);
  pinMode(TimeDown, INPUT_PULLUP);
  pinMode(SettingValue, INPUT_PULLUP);
  pinMode(ModeSwitch, INPUT_PULLUP);
  pinMode(Buzzer, OUTPUT);

  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.print("Time");
}

void loop() {
  UpdateTime(); // Aktualizácia času

  // Nastavenie času nahor
  if (digitalRead(TimeUp) == LOW || SettingTimeUp) {
    SettingTime = true;
    if (Mode == 1) // v prípade nastavenia hodín: 
    { 
      if (settingValue == 0) {
        hours++;
        
        if (hours >= 24) {
          lcd.clear();
          lcd.print("Time");
          lcd.setCursor(0,1);
          hours = 0;
        }
      } else if (settingValue == 1) {
        minutes++;
        if (minutes >= 60) {
          lcd.clear();
          lcd.print("Time");
          lcd.setCursor(0,1);
          minutes = 0;
        }
      }
    } 
    else if (Mode == 2) // v prípade nastavenia budíka 
    {
      if (settingValue == 0) {
        SettingTime = false;
        alarmHours++;
        if (alarmHours >= 24) {
          lcd.clear();
          lcd.print("Alarm");
          lcd.setCursor(0,1);
          alarmHours = 0;
        }
      } else if (settingValue == 1) {
        SettingTime = false;
        alarmMinutes++;
        if (alarmMinutes >= 60) {
          lcd.clear();
          lcd.print("Alarm");
          lcd.setCursor(0,1);
          alarmMinutes = 0;
        }
      }
    }
    DisplayTime();
    delay(200); // Malé oneskorenie pre stabilné čítanie tlačidla
    SettingTime = false; // Resetovanie premenných
    SettingTimeUp = false;
  } 

  // Nastavenie času nadol
  if (digitalRead(TimeDown) == LOW || SettingTimeDown) {
    if (Mode == 1) // v prípade nastavenia hodín: 
    {
      if (settingValue == 0) {
        hours--;
        if (hours < 0) {
          lcd.clear();
          lcd.print("Time");
          lcd.setCursor(0,1);
          hours = 23;
        }
        
      } else if (settingValue == 1) {
        minutes--;
        if (minutes < 0) {
          lcd.clear();
          lcd.print("Time");
          lcd.setCursor(0,1);
          minutes = 59;
        }
      }
    } 
    else if (Mode == 2) // v prípade nastavenia budíka: 
    {
      if (settingValue == 0) {
        SettingTime = false;
        alarmHours--;
        if (alarmHours < 0) {
          lcd.clear();
          lcd.print("Alarm");
          lcd.setCursor(0,1);
          alarmHours = 23;
        }
      } else if (settingValue == 1) {
        SettingTime = false;
        alarmMinutes--;
        if (alarmMinutes < 0) {
          lcd.clear();
          lcd.print("Alarm");
          lcd.setCursor(0,1);
          alarmMinutes = 59;
        }
      }
    }
    DisplayTime();
    delay(200); // Malé oneskorenie pre stabilné čítanie tlačidla
    SettingTime = false; // Resetovanie premenných
    SettingTimeDown = false;
  } 

  if (digitalRead(SettingValue) == LOW && !SettingTime)   // Prepínanie medzi nastavením hodín a minút
  {
    settingValue++;
    if (settingValue > 1) {
      settingValue = 0;
    }
    if (settingValue == 0) {
      lcd.clear();
      lcd.print("Set Hours");
      delay(500);
      lcd.clear();
    } 
    else if (settingValue == 1)
    {
      lcd.clear();
      lcd.print("Set Minutes");
      delay(500);
      lcd.clear();
    }
    if(Mode == 1)
    {
     lcd.print("Time");
     DisplayTime();
    }
    else if(Mode == 2)
    {
      lcd.print("Alarm");
      DisplayTime();
    }
    delay(200); // Malé oneskorenie pre stabilné čítanie tlačidla
  }

  // Prepínanie režimov
  if (digitalRead(ModeSwitch) == LOW && !alarmIsActive)  // Prepínanie medzi režimami hodín a budíka
  {
    Mode++;
    if(Mode > 2)
    {
      Mode = 1;
    }
    if(Mode == 1)
    {
      lcd.clear();
      lcd.print("Time");
      lcd.setCursor(0,1);
      DisplayTime();
    }
    else if(Mode == 2)
    {
      lcd.clear();
      lcd.print("Alarm");
      lcd.setCursor(0,1);
      DisplayTime();
    }
  }
  else if (digitalRead(ModeSwitch) == HIGH)
  {
    alarmIsActive = false;
  }

  // Kontrola alarmu
  if (hours == alarmHours && minutes == alarmMinutes && seconds == alarmSeconds) {
    Alarm();
  }

  // Aktualizácia bzučiaka
  if (alarmIsActive) {
    tone(Buzzer, 2000, 1000); // Zapnutie bzučiaka s frekvenciou 2000Hz a dĺžkou 1000ms
  } else {
    noTone(Buzzer); // Vypnutie bzučiaka
  }
}

// Aktualizácia času
void UpdateTime() 
{
  if (!SettingTime) 
  {
    // Kontrola stlačenia tlačidla TimeUp aj po uplynutí jednej sekundy
    if (digitalRead(TimeUp) == LOW) {
      SettingTime = true;
      SettingTimeUp = true;
    }
    if(digitalRead(TimeDown) == LOW)
    {
      SettingTime = true;
      SettingTimeDown = true;
    }
  }
  if (!SettingTime) {
    seconds++;
    if (seconds >= 60) {
      seconds = 0;
      minutes++;
      if (minutes >= 60) {
        minutes = 0;
        hours++;
        if (hours >= 24) {
          hours = 0;
        }
      }
    }
    DisplayTime();
    delay(1000); // Každú sekundu
  }
}

// Zobrazenie času v oboch režimoch hodín a budíka
void DisplayTime() 
{
  if(Mode == 1)
  {
    lcd.setCursor(0,1);
    lcd.print(hours < 10 ? "0" : ""); // Zabezpečuje zobrazenie hodín formáte 00:00:00, ak je premenná jednociferná, pridá pred tú premennú cifru 0 aby sa dodržal formát
    lcd.print(hours);
    lcd.print(":");
    lcd.print(minutes < 10 ? "0" : "");
    lcd.print(minutes);
    lcd.print(":");
    lcd.print(seconds < 10 ? "0" : "");
    lcd.print(seconds);    
  }
  else if(Mode == 2)
  {
    lcd.setCursor(0,1);
    lcd.print(alarmHours < 10 ? "0" : ""); // Zabezpečuje zobrazenie hodín formáte 00:00:00, ak je premenná jednociferná, pridá pred tú premennú cifru 0 aby sa dodržal formát
    lcd.print(alarmHours);
    lcd.print(":");
    lcd.print(alarmMinutes < 10 ? "0" : "");
    lcd.print(alarmMinutes);
    lcd.print(":");
    lcd.print(alarmSeconds < 10 ? "0" : "");
    lcd.print(alarmSeconds);
  }
}

// Funkcia pre zapnutie alarmu
void Alarm() {
  tone(Buzzer, 2000, 1000);
  delay(500);
  lcd.clear();
  lcd.print("ALARM IS ON");
  alarmIsActive = true;
}