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

// LCD Configuration (16x4 display)
LiquidCrystal_I2C lcd(0x27, 16, 4); // Use 0x3F if address doesn't work

// DHT22 Configuration
#define DHTPIN 2
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

// Update interval
const unsigned long readInterval = 2000;
unsigned long previousMillis = 0;

void setup() {
  Serial.begin(9600);
  
  // Initialize LCD
  lcd.init();
  lcd.backlight();
  lcd.clear();
  
  // Start DHT sensor
  dht.begin();
  
  // Display header
  lcd.setCursor(0, 0);
  lcd.print("Environment Monitor");
  lcd.setCursor(0, 1);
  lcd.print("----------------");
}

void loop() {
  if (millis() - previousMillis >= readInterval) {
    previousMillis = millis();
    
    // Read sensor data
    float humidity = dht.readHumidity();
    float tempC = dht.readTemperature();
    
    // Check if readings are valid
    if (isnan(humidity) || isnan(tempC)) {
      displayError();
      return;
    }
    
    // Convert Celsius to Fahrenheit
    float tempF = (tempC * 9.0 / 5.0) + 32;

    // Update display
    updateDisplay(tempC, tempF, humidity);
    
    // Serial output for debugging
    printSerial(tempC, tempF, humidity);
  }
}

void updateDisplay(float tempC, float tempF, float humidity) {
  // Clear previous readings
  lcd.setCursor(0, 2);
  lcd.print("                ");
  lcd.setCursor(0, 3);
  lcd.print("                ");

  // Line 2: Temperature
  lcd.setCursor(0, 2);
  lcd.print("Temp: ");
  lcd.print(tempC, 1);
  lcd.write(223); // Degree symbol
  lcd.print("C  ");
  lcd.print(tempF, 1);
  lcd.write(223);
  lcd.print("F");

  // Line 3: Humidity
  lcd.setCursor(0, 3);
  lcd.print("Humidity: ");
  lcd.print(humidity, 1);
  lcd.print("% RH");
}

void displayError() {
  lcd.setCursor(0, 2);
  lcd.print("  Sensor Error!  ");
  lcd.setCursor(0, 3);
  lcd.print(" Check Connection ");
}

void printSerial(float tempC, float tempF, float humidity) {
  Serial.print("Temperature: ");
  Serial.print(tempC);
  Serial.print("°C / ");
  Serial.print(tempF);
  Serial.print("°F\t");
  Serial.print("Humidity: ");
  Serial.print(humidity);
  Serial.println("%");
}