/*
  Weather Station & Clock with DHT11/DHT22, DS3231 RTC, and I2C LCD
  For Arduino Uno
  Displays: Time (HH:MM:SS), Date (DD/MM), Temperature (°C), Humidity (%)
  Works with both DHT11 and DHT22.
*/

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

// ---------- LCD Configuration ----------
// Common I2C addresses: 0x27 or 0x3F. Change if your LCD does not work.
LiquidCrystal_I2C lcd(0x27, 16, 2);

// ---------- RTC Configuration ----------
RTC_DS3231 rtc;

// ---------- DHT Configuration ----------
#define DHTPIN 2          // Digital pin connected to DHT data pin

// ===== CHOOSE YOUR SENSOR: Uncomment ONE of the following lines =====
// #define DHTTYPE DHT11    // For DHT11 (cheaper, less accurate, NOT supported in Wokwi)
#define DHTTYPE DHT22      // For DHT22 (more accurate, Wokwi-compatible)

DHT dht(DHTPIN, DHTTYPE);

// ---------- Timing ----------
unsigned long lastDisplayUpdate = 0;
const unsigned long displayUpdateInterval = 1000;   // update every 1000 ms (1 sec)

void setup() {
  Serial.begin(9600);
  Serial.println("Weather Station & Clock starting...");

  // --- LCD Initialization ---
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Weather Station");
  lcd.setCursor(0, 1);
  lcd.print("   v2.0 (DHT11/22)");
  delay(2000);
  lcd.clear();

  // --- DHT Initialization ---
  dht.begin();

  // --- RTC Initialization ---
  if (!rtc.begin()) {
    lcd.setCursor(0, 0);
    lcd.print("RTC Error!");
    Serial.println("Could not find RTC module. Check wiring.");
    while (1);   // halt program
  }

  // --- RTC Time Setting (DO THIS ONLY ONCE) ---
  // Uncomment the line below, upload the code, then re-comment and upload again.
  // rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));

  // Optional: manual set (year, month, day, hour, minute, second)
  // rtc.adjust(DateTime(2026, 6, 4, 14, 30, 0));
}

void loop() {
  // Update display exactly once per second (non-blocking)
  if (millis() - lastDisplayUpdate >= displayUpdateInterval) {
    lastDisplayUpdate = millis();

    // --- Read DHT sensor ---
    float humidity = dht.readHumidity();          // in %
    float temperatureC = dht.readTemperature();   // in Celsius

    // Check if reading failed (sensor disconnected or timing issue)
    if (isnan(humidity) || isnan(temperatureC)) {
      Serial.println("DHT read error!");
      lcd.setCursor(0, 0);
      lcd.print("Sensor Error!   ");
      lcd.setCursor(0, 1);
      lcd.print("Check wiring    ");
      return;   // skip the rest of this loop iteration
    }

    // --- Read RTC ---
    DateTime now = rtc.now();

    // --- Display on LCD ---
    // Row 0: Time and Humidity
    lcd.setCursor(0, 0);
    lcd.print("Time:");
    if (now.hour() < 10) lcd.print("0");
    lcd.print(now.hour());
    lcd.print(":");
    if (now.minute() < 10) lcd.print("0");
    lcd.print(now.minute());
    lcd.print(":");
    if (now.second() < 10) lcd.print("0");
    lcd.print(now.second());

    lcd.setCursor(13, 0);
    lcd.print((int)humidity);   // integer part only
    lcd.print("%");

    // Row 1: Date and Temperature
    lcd.setCursor(0, 1);
    lcd.print("Date: ");
    if (now.day() < 10) lcd.print("0");
    lcd.print(now.day());
    lcd.print("/");
    if (now.month() < 10) lcd.print("0");
    lcd.print(now.month());

    lcd.setCursor(12, 1);
    lcd.print(temperatureC, 1);   // one decimal place
    lcd.print("C");
  }
}