#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
#include <RTClib.h>

// I2C LCD's address
#define LCD_ADDRESS 0x27 // Your LCD I2C address may be different; check the LCD documentation

// LCD object
LiquidCrystal_I2C lcd(LCD_ADDRESS, 20, 4);

// Define Keypad's digital pins
const byte ROW_NUM = 4;
const byte COLUMN_NUM = 4;

char keys[ROW_NUM][COLUMN_NUM] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

byte pin_rows[ROW_NUM] = {9, 8, 7, 6};
byte pin_column[COLUMN_NUM] = {5, 4, 3, 2};

Keypad keypad = Keypad(makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM);
RTC_DS1307 rtc;

unsigned long currentTime = 0;
unsigned long refreshInterval = 1000; // 刷新间隔，单位：毫秒

int defaultYear = 2023;
int defaultMonth = 10;
int defaultDay = 17;
int setHour = 0;
int setMinute = 0;
int setSecond = 0;

boolean settingTime = false;

void setup() {
  Wire.begin();
  rtc.begin();

  if (!rtc.isrunning()) {
    Serial.println("RTC is NOT running!");
    // 设置默认时间
    rtc.adjust(DateTime(defaultYear, defaultMonth, defaultDay, 0, 0, 0));
  }

  lcd.begin(20, 4); // 20 columns, 4 rows
  lcd.backlight(); // Turn on the backlight
  lcd.setCursor(0, 0);
  lcd.print("Digital Clock");
  delay(2000);
}

void loop() {
  char key = keypad.getKey();

  if (key) {
    if (key == 'A') {
      showDateTime();
    } else if (key == 'B') {
      // 进入设置模式
      settingTime = true;
      setClock();
      settingTime = false;
      delay(2000); // 延迟一段时间以确保设置被应用
    }
  }

  updateClock();
  delay(10); // 防止过于频繁的刷新
}

void updateClock() {
  if (millis() - currentTime >= refreshInterval) {
    currentTime = millis();
    if (!settingTime) {
      showDateTime();
    }
  }
}

void showDateTime() {
  DateTime now = rtc.now();
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Time: ");
  lcd.print(now.hour(), DEC);
  lcd.print(':');
  lcd.print(now.minute(), DEC);
  lcd.print(':');
  lcd.print(now.second(), DEC);
  lcd.setCursor(0, 2);
  lcd.print("Date: ");
  lcd.print(now.year(), DEC);
  lcd.print('/');
  lcd.print(now.month(), DEC);
  lcd.print('/');
  lcd.print(now.day(), DEC);
}

void setClock() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Set Hour: ");
  setHour = setNumericValue();
  lcd.setCursor(0, 1);
  lcd.print("Set Minute: ");
  setMinute = setNumericValue();
  lcd.setCursor(0, 2);
  lcd.print("Set Second: ");
  setSecond = setNumericValue();

  DateTime newTime = rtc.now();
  newTime = DateTime(newTime.year(), newTime.month(), newTime.day(), setHour, setMinute, setSecond);
  rtc.adjust(newTime);
}

int setNumericValue() {
  int value = 0;
  char key;
  while (true) {
    key = keypad.getKey();
    if (key >= '0' && key <= '9') {
      lcd.print(key);
      value = value * 10 + (key - '0');
    } else if (key == '#') {
      break;
    }
    delay(100);
  }
  return value;
}