//DHT sensor
#include "DHT.h"
#define DHT11Pin 2
#define DHTType DHT11
//OLED
#include  <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

DHT  HT(DHT11Pin,DHTType);
float humi;
float tempC;
float tempF;

//OLED  define
#define SCREEN_WIDTH 128 //OLED display width, in pixels
#define SCREEN_HEIGHT  64 //OLED display height, in pixels
//SSD1306 display connected  to I2C (SDA, SCL pins)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT,  &Wire, -1);

void setup() {
  Serial.begin(9600);
  //For DHT11
  HT.begin();
  //Necessary code for OLED I2C
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C))  { // Address 0x3D for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  display.display(); //Displays the starting logo
  delay(1000); 
  display.clearDisplay();
}

void loop() {
 delay(1000);
 humi =  HT.readHumidity();
 tempC = HT.readTemperature();
 tempF = HT.readTemperature(true);

 display.clearDisplay();
  oledDisplayHeader();
 //configures the position of the readings. (charactersize, x axis value, y axis value, reading, symbol)
oledDisplay(2,90,28,humi,"%");
 oledDisplay(3,-10,44,tempC,"C");
  oledDisplay(3,-10,16,tempF,"F");

 display.display(); 
 
}

void  oledDisplayHeader(){
  //configures position and qualities of headers
 display.setTextSize(1);
 display.setTextColor(WHITE);
  display.setCursor(0, 0);
 display.print("Temperature");
 display.setCursor(80,  0);
 display.print("Humidity");
}
void oledDisplay(int size, int x,int  y, float value, String unit){
 int charLen=18;
 int xo=x+charLen*3.2;
  int xunit=x+charLen*3.6;
 int xval = x; 
 display.setTextSize(size);
 display.setTextColor(WHITE);
  
 if (unit=="%"){
   display.setCursor(x, y);
   display.print(value,0);
   display.print(unit);
 } else {
   if (value>99){
    xval=x;
   }  else {
    xval=x+charLen;
   }
   display.setCursor(xval, y);
   display.print(value,0);
   display.drawCircle(xo, y+2, 2, WHITE);  // print degree symbols
   display.setCursor(xunit,  y);
   display.print(unit);
 }
 
}