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

#define DHTPIN 8    // DHT22 sensor pin
#define DHTTYPE DHT22 // DHT22 (AM2302)

DHT dht(DHTPIN, DHTTYPE); // Initialize DHT sensor
RTC_DS1307 rtc;           // Initialize RTC
LiquidCrystal_I2C lcd(0x27, 20, 4);  // Set LCD address to 0x27 for a 20x4 LCD

void setup() {
  lcd.init();    // Initialize LCD
  lcd.backlight();  // Turn on the backlight
  dht.begin();    // Initialize DHT sensor
  if (!rtc.begin()) {
    lcd.setCursor(0, 0);
    lcd.print("Couldn't find RTC");
    while (1);
  }

  if (!rtc.isrunning()) {
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));  // Set RTC to compile time
  }
}

void loop() {
  DateTime now = rtc.now();  // Get current time
  float temperature = dht.readTemperature();  // Read temperature
  float humidity = dht.readHumidity();        // Read humidity

  // Display date: dd/mm/yyyy in Thai Buddhist year
  lcd.setCursor(0, 0);
  lcd.print(now.day() < 10 ? "0" : ""); lcd.print(now.day());
  lcd.print("/");
  lcd.print(now.month() < 10 ? "0" : ""); lcd.print(now.month());
  lcd.print("/");
  lcd.print(now.year() + 543);  // Convert to Thai Buddhist year

  // Display time: hh:mm with blinking colon and day of the week
  lcd.setCursor(0, 1);
  lcd.print(now.hour() < 10 ? "0" : ""); lcd.print(now.hour());
  lcd.print((millis() / 1000) % 2 == 0 ? ":" : " ");  // Blinking colon
  lcd.print(now.minute() < 10 ? "0" : ""); lcd.print(now.minute());
  lcd.setCursor(14, 1);
  lcd.print(dayOfTheWeek(now.dayOfTheWeek()));  // Display day of the week

  // Display temperature and humidity
  lcd.setCursor(0, 2);
  lcd.print("Temp: ");
  lcd.print(isnan(temperature) ? "Error" : String(temperature) + " C");

  lcd.setCursor(0, 3);
  lcd.print("Humidity: ");
  lcd.print(isnan(humidity) ? "Error" : String(humidity) + " %");

  delay(1000);
}

String dayOfTheWeek(uint8_t day) {
  switch (day) {
    case 0: return "Sun";
    case 1: return "Mon";
    case 2: return "Tue";
    case 3: return "Wed";
    case 4: return "Thu";
    case 5: return "Fri";
    case 6: return "Sat";
    default: return "";
  }
}