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

#define DHTPIN 12        // DHT22 data pin connected to GPIO 4
#define DHTTYPE DHT22

DHT dht(DHTPIN, DHTTYPE);

// OLED display size
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

void setup() {
  Serial.begin(115200);

  dht.begin();

  // Initialize OLED
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("OLED init failed");
    while (true);
  }

  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(WHITE);
}

void loop() {
  float temp = dht.readTemperature();    // Celsius
  float hum = dht.readHumidity();

  display.clearDisplay();
  display.setCursor(0, 0);

  if (isnan(temp) || isnan(hum)) {
    display.println("Sensor Err!");
  } else {
    display.print("T:");
    display.print(temp, 1);
    display.println(" C");

    display.print("H:");
    display.print(hum, 1);
    display.println(" %");
  }

  display.display();
  delay(1000);
}