#include "FS.h"                       //setting up the various libraries need for operation
#include "SD.h"
#include <SPI.h>
#include <stdio.h>
#include <stdlib.h>





int analogPin=36;                     //creation of variables for the rest of the program
float rst = 0.0;
float vout = 0.0;
float avg = 0.0;
String avgStr ;
float total = 0.0;
float Min = 90.0;
String MinStr ;
float Max = 0.0;
String MaxStr ;
float min10avg = 0.0;
String min10avgStr ;
float total10min = 0.0;
float tempk= 0.0;
float tempf= 0.0;
int incre = 0;

void min10average(float total10min){                                   //function that handles the 10 minute averages
  min10avg = total10min/600.0 ;
  min10avgStr = String(min10avg) + "F" + "," ;
  appendFile(SD, "/TempData.txt", min10avgStr.c_str() );
  
return;
} 



void minimum(float tempf){                                            //function that checks to see if a measurement is less than 
  if( tempf < Min ){
    Min = tempf ;
    MinStr = "Min " + String(Min) + "F" + "," ;
  }
return;
}

void maximum(float tempf){                                             //function that checks to see if a measurement is greater than the current max value
  if( tempf > Max){
    Max = tempf ;
    MaxStr = "Max " + String(Max) + "F" + "," ;
  }
return;
}

void continualavg(float tempf){                                        //function that handles the running/continual average
  total = total + tempf;
  avg = (total/incre);
  avgStr = "continual average " + String(avg) + "F" + "," ;
return;
}

float converter(float vout){                                           //function that handles converting the value from reading the thermistor connected pin to a Fahrenheit value
  rst =  10000.0*vout/(3.3-vout);                                      // this gives the actual resistance of the termistor based on supply voltage and value of resistor that is connected to the thermistor

  tempk =  1.0/(1.0/298.15+log(rst/10000.0)/4300.0) ;                  //converts thermistor resistance to temperature in kelvin

  tempf =  (tempk - 273.15)*9.0/5.0+32.0;                               //conversion from kelvin to fahrenheit
  
  tempf = tempf - 4.0 ;
  
  return tempf;
}

void appendFile(fs::FS &fs, const char * path, const char * message){           //function for appending a string to a file
  Serial.printf("Appending to file: %s\n", path);

  File file = fs.open(path, FILE_APPEND);                                       //status check for if the file opens successfully
  if(!file){
    Serial.println("Failed to open file for appending");
    return;
  }
  if(file.print(message)){
    Serial.println("Message appended");                                          //details on status of appending
  } else {
    Serial.println("Append failed");
  }
  file.println();
  file.close();
}

void readFile(fs::FS &fs, const char * path){                                   //function that opens the file to read its contents and then display them over serial
  Serial.printf("Reading file: %s\n", path);

  File file = fs.open(path);
  if(!file){
    Serial.println("Failed to open file for reading");
    return;
  }

  Serial.print("Read from file: ");
  while(file.available()){
    Serial.write(file.read());
  }
  file.close();
}

void writeFile(fs::FS &fs, const char * path, const char * message) {           //function that opens file and can write data to it, it also has the capability to create a file if one doesn't already exist
  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 setup() {
  // put your setup code here, to run once:
  Serial.begin (115200) ;                                         //sets up baud rate
  SD.begin();                                                     //sets up SD card


  File file = SD.open("/TempData.txt");                           // checks for file of indicated name, and calls writeFile function to create one if needed
  if(!file) {
    Serial.println("File doesn't exist");
    Serial.println("Creating file...");
    writeFile(SD, "/TempData.txt", "Begin");
  }
  else {
    Serial.println("File already exists");  
  }
  file.close();
}



void loop() {
  // put your main code here, to run repeatedly:
  while(millis()< 86600000){                                      //milis function set to a bit over 24hrs worth of milliseconds to trigger the program to do its final appending
    Serial.flush();                                               //clears serial buffer
    if(Serial.available()==0){                                    //checks to make sure nothing is in serial buffer
      int i= 0;
      for(i=0; i<600; i++){                                       //for loop for each 10 minute interval
        
      vout =  analogRead(analogPin)*3.3/4095.0;
      
      incre = incre + 1 ;
      
      tempf = converter(vout);
    
      Serial.print(tempf);                                        //prints fahrenheit value along with unit label
      Serial.println("F");

      minimum(tempf);                                             //function calls for the respective, min,max and rolling average functions
      maximum(tempf);
      continualavg(tempf);

      total10min = total10min + tempf;                            //running total for the 10 minute interval
    
      delay (1000);                                                
        if(Serial.available()>0){                                 //checks to see if the is anything in the serial buffer and restarts loop if so
        return;
        }
      }
      min10average(total10min);                                   
      total10min = 0.0;                                           //resets 10 minute average total for the next cycle
    } else {
      

      
      appendFile(SD, "/TempData.txt", avgStr.c_str() );           //appends file with continual average value
      delay(1000);
      appendFile(SD, "/TempData.txt", MinStr.c_str() );           //appends file with min value
      delay(1000);
      appendFile(SD, "/TempData.txt", MaxStr.c_str() );           //appends file with max value
      delay(1000);

      readFile(SD, "/TempData.txt");                              //prints out file contents to serial

      delay(10000000);                                            //really long delay to basically freeze program
      

    } 
  
  } 

  appendFile(SD, "/TempData.txt", avgStr.c_str() );               //same appending block just for when the millis function registers that enough time has passed
  delay(1000);
  appendFile(SD, "/TempData.txt", MinStr.c_str() );
  delay(1000);
  appendFile(SD, "/TempData.txt", MaxStr.c_str() );
  delay(1000);

  readFile(SD, "/TempData.txt");

  delay(10000000);

}