#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <DHT.h>

// OLED Display Settings 
#define SCREEN_WIDTH 128 
#define SCREEN_HEIGHT 64 
#define OLED_RESET 4 
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// DHT22 Settings
#define DHTPIN 2       // Connect DHT22 Data pin to Digital Pin 2
#define DHTTYPE DHT22  
DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(9600);
  
  // Initialize DHT sensor
  dht.begin();

  // Initialize OLED (Retained from your program)
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { 
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); 
  }
  
  display.clearDisplay();
  display.setTextColor(WHITE);
  display.display();
}

void loop() {
  // DHT22 requires a 2-second delay between readings for accuracy
  delay(2000);

  float humidity = dht.readHumidity();
  float temperature = dht.readTemperature(); // Celsius

  // Error handling: if sensor is disconnected or failing
  if (isnan(humidity) || isnan(temperature)) {
    display.clearDisplay();
    display.setCursor(0, 10);
    display.setTextSize(1);
    display.println("Sensor Error!");
    display.display();
    return;
  }

  // Update Display
  display.clearDisplay();

  // Draw a simple border for a technical look
  display.drawRect(0, 0, 128, 64, WHITE);

  // Temperature Display
  display.setTextSize(1);
  display.setCursor(10, 10);
  display.print("TEMPERATURE");
  
  display.setTextSize(2);
  display.setCursor(10, 22);
  display.print(temperature, 1); // 1 decimal place
  display.print(" C");

  // Humidity Display
  display.setTextSize(1);
  display.setCursor(10, 42);
  display.print("HUMIDITY");

  display.setTextSize(2);
  display.setCursor(10, 52);
  display.print(humidity, 1);
  display.print(" %");

  display.display();
}