//first calibrate dry sensor value and pure water. We might want to consider calibrating under extremely dry conditions if we want more accuracy in drier values.
const int dry = 560; // value for dry sensor
const int wet = 305; // value for wet sensor
const int chipSelect = 4;

#include "RTClib.h"
#include <SPI.h>
#include <SD.h>

RTC_DS3231 rtc;
char daysOfTheWeek[7][12] = {"Sunday", "Monday", "Wednesday", "Thursday", "Friday", "Saturday"};
int moist1;
// SD CARD READER
File myFile;

void setup() {
  Serial.begin(9600);  //com enable
  delay (1000);
  if (!rtc.begin ()) {
    Serial.println ("couldn't find RTC");
    Serial.flush();
    while (1) delay(1000);
  }

  if (rtc.lostPower()) {
    Serial.println("RTC lost power, let's set the time!");
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));

  }
  //wait for serial port to connect.

  Serial.print("Initializing SD card...");

  // 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.");
  }

  // When time needs to be re-set on a previously configured device, the
  // following line sets the RTC to the date & time this sketch was compiled
  // rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  // This line sets the RTC with an explicit date & time, for example to set
  // January 21, 2014 at 3am you would call:
  // rtc.adjust(DateTime(2014, 1, 21, 3, 0, 0));
}

void loop() {
  //make a string for assembling the data to log:
  String dataString = "";

  DateTime now = rtc.now();
  Serial.print (now.year(), DEC);
  Serial.print ("/");
  Serial.print (now.month(), DEC);
  Serial.print ("(");
  Serial.print (daysOfTheWeek[now.dayOfTheWeek()]);
  Serial.print (")");
  Serial.print (now.hour(), DEC);
  Serial.print (":");
  Serial.print (now.minute(), DEC);
  Serial.print (":");
  Serial.print (now.second(), DEC);
  Serial.print (",");
  {
    int sensorValue1 = analogRead(A1);
    int moist1 = analogRead(A1);
    moist1 = analogRead(A1); //take reading 1
    int percentMoisture1 = map(sensorValue1, wet, dry, 100, 0);
    Serial.print(moist1);
    Serial.print(",");
    Serial.print(percentMoisture1);
    Serial.print(",");
    Serial.println("%");
    myFile = SD.open("test.txt", FILE_WRITE);
    if (myFile) {
      myFile.print (now.year(), DEC);
      myFile.print ("/");
      myFile.print (now.month(), DEC);
      myFile.print ("(");
      myFile.print (daysOfTheWeek[now.dayOfTheWeek()]);
      myFile.print (")");
      myFile.print (now.hour(), DEC);
      myFile.print (":");
      myFile.print (now.minute(), DEC);
      myFile.print (":");
      myFile.print (now.second(), DEC);
      myFile.print (",");
      myFile.print(moist1);
      myFile.print(",");
      myFile.print(percentMoisture1);
      myFile.println("%");
      myFile.close(); // close the file
    }
    // if the file didn't open, print an error:
    else {
      Serial.println("error opening test.txt");
    }
  }
  delay(1000);
  if (Serial.read() == 'p') PrintSD();
}

void PrintSD(){
    String s = "-> ";
    myFile = SD.open("test.txt");
    if (myFile) {
      while (myFile.available()) {
            char c = myFile.read();
            if (c != 10) s += c;
            else {
              Serial.println(s);
              s = "-> ";
            }
      }
     myFile.close(); 
    } 
}