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

#define SCREEN_WIDTH 128 // OLED display width,  in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

#include <DHT.h>
#define DHT22_PIN  33 // ESP32 pin GPIO21(33) connected to DHT22 sensor

DHT dht22(DHT22_PIN, DHT22);

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


void setup() {
   // initialize the DHT22 sensor
  Serial.begin(9600);
  dht22.begin();

// initialize OLED display with address 0x3C for 128x64
if (!oled.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
  Serial.println(F("SSD1306 allocation failed"));
  while (true);
}
  delay(1000);
  oled.clearDisplay();

  oled.setTextSize(2);
  oled.setTextColor(WHITE);
  oled.setCursor(45, 20);
  oled.println("Test");
  oled.display();
  delay(1000);
  oled.clearDisplay();
  oled.drawCircle(64, 32, 15, WHITE);
  oled.display();
  delay(1000);
  oled.clearDisplay();

}

void loop() {

  // read humidity
  float humi  = dht22.readHumidity();
  // read temperature in Celsius
  float tempC = dht22.readTemperature();
  // read temperature in Fahrenheit
  float tempF = dht22.readTemperature(true);

  // check whether the reading is successful or not
  if ( isnan(tempC) || isnan(tempF) || isnan(humi)) {
    Serial.println("Failed to read from DHT22 sensor!");
  } else {
    Serial.print("Humidity: ");
    Serial.print(humi);
    Serial.print("%");

    Serial.print("  |  ");

    Serial.print("Temperature: ");
    Serial.print(tempC);
    Serial.print("°C  ~  ");
    Serial.print(tempF);
    Serial.println("°F");
  }

  oled.setTextSize(1);
  oled.setTextColor(WHITE);
  oled.setCursor(0, 7);
  oled.println("Temp: ");
  oled.setCursor(30, 7);
  oled.println(tempC);
  oled.drawCircle(65, 7, 2, WHITE);
  oled.setCursor(70, 7);
  oled.println("C");

  oled.setCursor(0, 50);
  oled.println("Humidity: ");
  oled.setCursor(55, 50);
  oled.println(humi);
  oled.setCursor(85, 50);
  oled.println("%");

  oled.setTextSize(2);
  oled.setCursor(0, 25);
  oled.println("CO: ");
  oled.setCursor(40, 25);
  oled.println("2000");
  oled.setCursor(90, 25);
  oled.println("PPM");
  oled.display();
  
}