#include "DHT.h"
#include <SPI.h>
#include <SD.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include "RTClib.h"


#define DHTPIN 2 
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define DHTTYPE DHT11
const int chipSelect = 10;

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C


//screen, temp, and clock objects
Adafruit_SSD1306 _display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
DHT dht(DHTPIN, DHTTYPE);
RTC_DS3231 rtc;


bool sdCardPresent = false;


void setup() {

  Serial.begin(9600);
  dht.begin();

//  #ifndef ESP8266
//    while (!Serial); // wait for serial port to connect. Needed for native USB
//  #endif


  if (! rtc.begin()) {
    Serial.println("Couldn't find RTC");
    Serial.flush();
    while (1) delay(10);
  }


  if (SD.begin(chipSelect)) {
    Serial.println("SD card is present during startup");
    sdCardPresent = true;
  } else {
    Serial.println("No SD card present during startup");
  }


  if(!_display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { 
    Serial.println(F("SSD1306 screen problem"));
  }
  
  _display.clearDisplay();         
}




void loop() {

  DateTime now = rtc.now();
  String year = String(now.year());
  String month = String(now.month());
  if (now.month() < 10) { month = "0" + String(now.month()) ;}
  String day = String(now.day());
  if (now.day() < 10) { day = "0" + String(now.day()) ;}
  String hour = String(now.hour());
  if (now.hour() < 10) { hour = "0" + String(now.hour()) ;}
  String minute = String(now.minute());
  if (now.minute() < 10) { minute = "0" + String(now.minute()) ;}
  String second = String(now.second());
  if (now.second() < 10) { second = "0" + String(now.second()) ;}


  String time = hour + ":" + minute + ":" + second ;
  String date = year + "-" + month  + "-" + day ;
  String timestamp = date + " " + time ;

  float rtc_c = rtc.getTemperature();
  float rtc_f = (rtc_c * 9 / 5 ) + 32 ;
  String rtcTemp = String(rtc_f);

  _display.clearDisplay(); 

  float dht_f = dht.readTemperature(true);
  float dht_h = dht.readHumidity();

  float average_of_both_temps = (rtc_f + dht_f) / 2 ;

  int16_t x, y;
  uint16_t textWidth, textHeight;

  _display.setTextSize(2);
  _display.setTextColor(WHITE, BLACK);

  //_display.getTextBounds(strHello, 0, 0, &x, &y, &textWidth, &textHeight);
  //_display.setCursor(_display.width() / 2 - textWidth / 2, _display.height() / 2 - textHeight / 2);
  _display.setCursor(0,0);
  _display.print(date);

  
  _display.setCursor(0,20);
  _display.print(String(average_of_both_temps) +  char(247) + " F");

  _display.setCursor(0,40);
  _display.print(String(dht_h) + "% Hum");

//  _display.setTextSize(1);
//  _display.setCursor(0,45);
//  _display.print("HAPPY NEW YEAR!!!");

  _display.display(); 

  String dataString = timestamp;
  dataString += ",";
  dataString += String(average_of_both_temps);
  dataString += ",";
  dataString += String(dht_h);


  if (sdCardPresent) {

    File dataFile = SD.open("templog.txt", FILE_WRITE);
    if (dataFile) {
      dataFile.println(dataString);
      dataFile.close();
      Serial.println(dataString);
      _display.setTextColor(WHITE, BLACK);
      _display.setTextSize(1);
      _display.setCursor(0,56);
      _display.print("              ");
    }
    else {
    Serial.println("error opening datalog.txt");
    _display.setTextSize(1);
    _display.setCursor(0,56);
    _display.print("SD CARD ERROR");
    sdCardPresent = false;
    }

  } else {
    Serial.println("SD card not present in main loop");
    _display.setTextSize(1);
    _display.setCursor(0,56);
    _display.print("SD CARD ERROR");

    Serial.println("checking if SD card returned.");
    if (SD.begin(chipSelect)) {
      Serial.println("SD card is present during startup");
      sdCardPresent = true;
    } else {
      Serial.println("No SD card present during startup");
    }  // end of sd re-check
        
  }

     _display.display(); 

    delay(60000);

}