#include <Arduino.h> //wg.print
//#include <DFRobot_DHT20.h>
#include <DHT20.h>
#include <SPI.h>                                               
#include <MQUnifiedsensor.h>
#include <EEPROM.h>
#include "time.h"
#include <string> 
#include <TFT_eSPI.h>

TFT_eSPI tft = TFT_eSPI();

struct tm timeinfo;                      //für time.h 

#include "RTClib.h"
RTC_DS3231 rtc;

#include "FS.h"
#include <SD.h> 
const int chipSelect = 33;              //Modifikation für Himalaya: CS  = GPIO33 
int WriteCounter = 100;

DFRobot_DHT20 dht20;

//Definitions for MQ-7
/************************Hardware Related Macros************************************/
#define         Board                   ("ESP-32") // Wemos ESP-32 or other board, whatever have ESP32 core.
#define         Pin                     (35)  //IO35 for your ESP32 WeMos Board, pinout here: https://i.pinimg.com/originals/66/9a/61/669a618d9435c702f4b67e12c40a11b8.jpg
/***********************Software Related Macros************************************/
#define         Type                    ("MQ-7") //MQ3 or other MQ Sensor, if change this verify your a and b values.
#define         Voltage_Resolution      (3.3) // 3V3 <- IMPORTANT. Source: https://randomnerdtutorials.com/esp32-adc-analog-read-arduino-ide/
#define         ADC_Bit_Resolution      (12) // ESP-32 bit resolution. Source: https://randomnerdtutorials.com/esp32-adc-analog-read-arduino-ide/
#define         RatioMQ7CleanAir        (27.5) //RS / R0 = 27.5 ppm 

/*****************************Globals***********************************************/
MQUnifiedsensor MQ7(Board, Voltage_Resolution, ADC_Bit_Resolution, Pin, Type);

int RedledPin = 4;
int GreenledPin = 2;
float SaveR0 = 0;

void writeFile(fs::FS &fs, const char * path, const char * message)
{
    Serial.printf("Writing file: %s\n", path);

    File file = fs.open(path, FILE_WRITE);
    if(!file)
    {
      Serial.println("Failed to open file for writing");
      return;
    }
    if(file.print(message))
    {
      Serial.println("File written");
    } 
    else 
    {
      Serial.println("Write failed");
    }
    file.close();
}
void appendFile(fs::FS &fs, const char * path, const char * message)
{
    Serial.printf("Appending to file: %s\n", path);

    File file = fs.open(path, FILE_APPEND);
    if(!file)
    {
      Serial.println("Failed to open file for appending");
      return;
    }
    if(file.print(message))
    {
      Serial.println("Message appended");
    }
     else 
    {
      Serial.println("Append failed");
    }
    file.close();
}

void deleteFile(fs::FS &fs, const char * path)
{
  Serial.printf("Deleting file: %s\n", path);
  if(fs.remove(path))
  {
    Serial.println("File deleted");
  } 
  else 
  {
    Serial.println("Delete failed");
  }
}

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
 
  Serial.println(Sketchname);
  pinMode(4, OUTPUT); 
  pinMode(2, OUTPUT);
      
  tft.init();
  tft.setRotation(0);     // Adjust Rotation of your screen (0-3)
  //tft.fillScreen(TFT_BLACK);
  tft.fillScreen(TFT_WHITE);
  tft.setTextColor(TFT_WHITE, TFT_BLACK);

 // see if the card is present and can be initialized:
  
  if (!SD.begin(chipSelect)) 
  {
    Serial.println("Card failed, or not present");
    // don't do anything more:
    //while (1);
  }
   
  Serial.println("card initialized.");
  
  delay(500);
  //new file for every start
  deleteFile(SD, "/CODaten.txt");
  writeFile(SD, "/CODaten.txt", "CO Messung\n"); 
  
  dht20.begin();
  //Serial.println("dht");
    
//Set math model to calculate the PPM concentration and the value of constants
  MQ7.setRegressionMethod(1); //_PPM =  a*ratio^b
  MQ7.setA(99.042); MQ7.setB(-1.518); // Configure the equation to calculate CO concentration value

  /*
    Exponential regression:
  GAS     | a      | b
  H2      | 69.014  | -1.374
  LPG     | 700000000 | -7.703
  CH4     | 60000000000000 | -10.54
  CO      | 99.042 | -1.518
  Alcohol | 40000000000000000 | -12.35
  */
  MQ7.init(); 
  Serial.println("MQ7init");
  /* 
    //If the RL value is different from 10K please assign your RL value with the following method:
    MQ7.setRL(10);
  */
    
  if (!rtc.begin()) 
  {
    Serial.println("Couldn't find RTC");
    Serial.flush();
    //while (1);
  }
  
  Serial.println("RTC begin");
  rtc.adjust(DateTime(__DATE__, __TIME__));
  float calcR0 = 0;  
  
  Serial.println("Calibrating please wait.");
  for(int i = 1; i<=10; i ++)
  {
    MQ7.update(); // Update data, the arduino will be read the voltage on the analog pin
    calcR0 += MQ7.calibrate(RatioMQ7CleanAir);
    Serial.print(".");
  }
  MQ7.setR0(calcR0/10);
  SaveR0 = (calcR0/10);
   
  MQ7.serialDebug(true); 
  Serial.println("  done!."); 
  Serial.print("calcR0: "); 
  Serial.println(calcR0); 
  delay(500);
  /*************** End calibration *******************/

  if(isinf(calcR0)) {Serial.println("Warning: Conection issue, R0 is infinite (Open circuit detected) please check your wiring and supply"); while(1);}
  if(calcR0 == 0){Serial.println("Warning: Conection issue found, R0 is zero (Analog pin shorts to ground) please check your wiring and supply"); while(1);}
  //MQ Setup and calibration finished
 //Test LEDs
  digitalWrite(GreenledPin, HIGH);
  delay(300);
  digitalWrite(GreenledPin, LOW); 
  
  digitalWrite(RedledPin, HIGH);
  delay(300);
  digitalWrite(RedledPin, LOW);
}

void loop() {
  // put your main code here, to run repeatedly:
  delay(10); // this speeds up the simulation
    float t = dht20.getTemperature();
  float h = dht20.getHumidity() * 100;

  Serial.print("Temperature: ");
  Serial.print(t);
  Serial.println(" C");
  Serial.print("Humidity: ");
  Serial.print(h);
  Serial.println(" %");

  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t) ) 
  {
    Serial.println(F("Fail read DHT!"));
    return;
  }

  //RTC
  DateTime dt = rtc.now();
        
  // MQ Reading and updating section
  MQ7.update(); // Update data, the arduino will be read the voltage on the analog pin
  MQ7.readSensor();

  float CO = MQ7.readSensor(); // Sensor will read PPM concentration using the model and a and b values setted before or in the setup

  float PPM = MQ7.getPPM();
 
  Serial.print("CO: ");
  Serial.println(CO);
  Serial.print("PPM: "); 
  Serial.println(PPM);

  if(CO>35)
  {
    tft.setTextColor(TFT_RED, TFT_BLACK);
  }      
  else 
  {
    //tft.setTextColor(TFT_WHITE, TFT_BLACK);
    tft.setTextColor(TFT_BLACK, TFT_WHITE);
  }
  //             x,  y
  tft.setCursor(50, 50, 4);
  tft.println("CO: ");
  tft.setCursor(130, 50, 4);
  tft.println(CO);

  tft.setCursor(50, 80, 4);
  tft.println("Temp:");
  tft.setCursor(130, 80, 4);
  tft.println(t);

  tft.setCursor(50, 110, 4);
  tft.println("Hum:");
  tft.setCursor(130, 110, 4);
  tft.println(h);

  tft.setCursor(50, 140, 4);
  tft.println("PPM:");
  tft.setCursor(130, 140, 4);
  tft.println(PPM);
  delay(500);

  if (CO > 35.0)
  {
    digitalWrite(GreenledPin, LOW);
    digitalWrite(RedledPin, HIGH);
  }
  else
  {
    digitalWrite(GreenledPin, HIGH);
    digitalWrite(RedledPin, LOW);
  } 

  if (WriteCounter > 10)
  {
    WriteCounter = 0;
    const char * datastring = " ";
    String Zeit = " ";

    Zeit = Zeit + dt.year() + "." + dt.month() + "." + dt.day() + " " + dt.hour() + ":" + dt.minute() + ":" + dt.second() + ", ";
    Zeit = Zeit + " R0: " + SaveR0 + " Temp.: " + t + " CO: " + CO + "\n";
    
    // make a string for assembling the data to log:
    datastring = Zeit.c_str();

    appendFile(SD, "/CODaten.txt", datastring);
  }
  WriteCounter++;
  delay(500);
}