// Arduino code for a clock with date and alarm using DS1307 RTC module

#include <LiquidCrystal.h>
#include <Keypad.h>
#include <DS1307RTC.h>

// Define the LCD pins
#define LCD_RS 12
#define LCD_EN 11
#define LCD_D4 10
#define LCD_D5 9
#define LCD_D6 8
#define LCD_D7 7

// Define the buzzer pin
#define BUZZER_PIN 6

// Define the keypad keys and pins
const char keys[4][4] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[4] = {5, 4, 3, 2};
byte colPins[4] = {A3, A2, A1, A0};

// Initialize the LCD, keypad, and RTC objects
LiquidCrystal lcd(LCD_RS, LCD_EN, LCD_D4, LCD_D5, LCD_D6, LCD_D7);
Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, 4, 4 );
DS1307RTC rtc;

// Define some constants for display modes and time formats
enum DisplayMode {DisplayClock, DisplayDate, DisplayAlarmTime};
enum TimeFormat {Hour24, Hour12};

// Define some global variables for display mode and time format preferences
DisplayMode displayMode = DisplayClock;
TimeFormat timeFormat = Hour24;

// Define some global variables for alarm time and status (on or off)
int alarmHour = 0;
int alarmMinute = 0;
bool alarmOn = false;

// Define some global variables for input buffer and count (used for setting time and alarm)
char inputBuffer[5] = "";
int inputCount = 0;

void setup() {

  // Set up the LCD size and turn on backlight
  lcd.begin(16, 2);

  // Turn on RTC oscillator and set time if needed (uncomment the following line)

  // rtc.write(tmElements_t {0,29,16,Friday,22,9,(uint8_t)(tmYearToY2k(2023))}); // Set time to hh:mm:ss day dd/mm/yyyy (change as needed)

}

void loop() {

  // Get current time and date from RTC module
  tmElements_t now;
  rtc.read(now);
  int hour = now.Hour;
  int minute = now.Minute;
  int second = now.Second;
  int day = now.Day;
  int month = now.Month;
  int year = tmYearToCalendar(now.Year);

  // Check if alarm is on and matches current time (ignore seconds)
  if (alarmOn && hour == alarmHour && minute == alarmMinute) {
    // Sound the buzzer for one second
    tone(BUZZER_PIN, 1000);
    delay(1000);
    noTone(BUZZER_PIN);
  }

  // Display current time, date, or alarm time based on display mode
  switch (displayMode) {

    case DisplayClock:
      // Display current time in 24-hour or 12-hour format
      lcd.clear();
      lcd.print("Time: ");
      if (timeFormat == Hour24) {
        // Display time in 24-hour format
        lcd.print(hour);
      } else {
        // Display time in 12-hour format
        lcd.print(hour % 12 == 0 ? 12 : hour % 12);
        lcd.print(hour < 12 ? " AM" : " PM");
      }
      lcd.print(":");
      if (minute < 10) {
        lcd.print("0");
      }
      lcd.print(minute);

      // Display alarm status and time format on the second row
      lcd.setCursor(0, 1);
      lcd.print("Alarm: ");
      lcd.print(alarmOn ? "ON " : "OFF");
      lcd.print(" ");
      lcd.print(timeFormat == Hour24 ? "24H" : "12H");

      break;

    case DisplayDate:
      // Display current date in dd/mm/yyyy format
      lcd.clear();
      lcd.print("Date: ");
      if (day < 10) {
        lcd.print("0");
      }
      lcd.print(day);
      lcd.print("/");
      if (month < 10) {
        lcd.print("0");
      }
      lcd.print(month);
      lcd.print("/");
      lcd.print(year);

      break;

    case DisplayAlarmTime:
      // Display alarm time in hh:mm format
      lcd.clear();
      lcd.print("Alarm: ");
      if (alarmHour < 10) {
        lcd.print("0");
      }
      lcd.print(alarmHour);
      lcd.print(":");
      if (alarmMinute < 10) {
        lcd.print("0");
      }
      lcd.print(alarmMinute);

  }

  // Read input from keypad and perform actions based on input
  char key = keypad.getKey();

  if (key != NO_KEY) {

    switch (key) {

      case 'A':
        // Change display mode to clock
        displayMode = DisplayClock;
        break;

      case 'B':
        // Change display mode to date
        displayMode = DisplayDate;
        break;

      case 'C':
        // Change display mode to alarm time
        displayMode = DisplayAlarmTime;
        break;

      case 'D':
        // Toggle alarm status (on or off)
        alarmOn = !alarmOn;
        break;

      case '*':
        // Toggle time format (24-hour or 12-hour)
        if (timeFormat == Hour24) {
          timeFormat = Hour12;
        } else {
          timeFormat = Hour24;
        }
        break;

      case '#':
        // Set current time or alarm time based on input buffer
        if (inputCount == 4) {
          // Parse input buffer as hhmm format
          int inputHour = (inputBuffer[0] - '0') * 10 + (inputBuffer[1] - '0');
          int inputMinute = (inputBuffer[2] - '0') * 10 + (inputBuffer[3] - '0');

          if (displayMode == DisplayClock) {
            // Set current time to input time
            rtc.write(tmElements_t {0, inputMinute, inputHour, now.Wday, now.Day, now.Month, now.Year});
          } else if (displayMode == DisplayAlarmTime) {
            // Set alarm time to input time
            alarmHour = inputHour;
            alarmMinute = inputMinute;
          }

          // Clear input buffer and count
          inputBuffer[0] = '\0';
          inputCount = 0;

        }
        break;

      default:
        // Append numeric key to input buffer if not full
        if (inputCount < 4 && key >= '0' && key <= '9') {
          inputBuffer[inputCount] = key;
          inputCount++;

          // Display input buffer on LCD
          lcd.setCursor(6, 1);
          for (int i = 0; i < inputCount; i++) {
            lcd.print(inputBuffer[i]);
          }

        }

    }

  }

}