#include <Wire.h>  // must be included here so that Arduino library object file references work
#include <RtcDS3231.h>
RtcDS3231<TwoWire> Rtc(Wire);
RtcDateTime dt, now, from, to;

//#define SPI_SPEED SPI_HALF_SPEED
#define SPI_SPEED SD_SCK_MHZ(4)
#define CS_PIN SS

#include <SdFat.h>
SdFat sd;
File file;

float sensor1_avg;
float sensor2_avg;
float sensor3_avg;
float sensor4_avg;

unsigned long counter_avg;
unsigned long calc_ms_avg;

bool average_sms;

bool sdmodul_err;
bool rtclock_err;
bool datalog_err;

void setup(void) {
  Serial.begin(9600);
  while (!Serial)
    ;
  ;
  sdmodul_err = !sd.begin(CS_PIN, SPI_SPEED);
  ;
  Rtc.Begin();
  //  RtcDateTime compiled = RtcDateTime(__DATE__, __TIME__);
  // Rtc.SetDateTime(compiled + 1 * 8 * 60 * 60);
  // Rtc.SetDateTime(RtcDateTime(2023, 1, 3, 7, 53, 00));

  pinMode(2, INPUT_PULLUP);
  pinMode(3, INPUT_PULLUP);

  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
}

void loop(void) {

  digitalWrite(8, bitRead(millis(), 8));

  now = Rtc.GetDateTime();
  rtclock_err = !Rtc.IsDateTimeValid();

  average();

  digitalWrite(7, average_sms);

}

int simulation(int *days) {

  static int DAYS = 1;
  static int simulate = 0;

  unsigned long timer = millis();
  static unsigned long buttonpress = timer;

  bool pin2 = !digitalRead(2);
  bool pin3 = !digitalRead(3);

  if (!simulate &  !pin2 & !pin3) buttonpress = timer;

  if (timer - buttonpress > 10000) {
    if (!simulate) {
      if (pin2)DAYS = 31;
      else DAYS = 1;
      simulate = 1;
    } else simulate = 2;
    if (rtclock_err )simulate = 1;
  }
  if (timer - buttonpress > 99999) simulate = 0;

  if (simulate) *days = DAYS;

  return simulate;
}

void average() {

  int days = 1;

  int simulate = simulation(&days);
  if (simulate == 1) goto m1;
  if (simulate == 2) goto m2;

  if (rtclock_err | now.Hour() != 12) {
m1:
    average_sms = false;
    return;
  }
  if (now.Day() == 1)days = 31;

m2:

  if (sdmodul_err | datalog_err)return;

  if (average_sms) return;
  else average_sms = true;

  counter_avg = 0;
  sensor1_avg = 0.0f;
  sensor2_avg = 0.0f;
  sensor3_avg = 0.0f;
  sensor4_avg = 0.0f;

  static char date[11];
  static char FILE[15];
  static char data[48];

  static char col1[9], col2[9], col3[9], col4[9];

  from = now;

  calc_ms_avg = millis();

  for (int i = 1; i <= days; i++) {

    int j = from.Day();
    from = from - 86400;
    int k = from.Day();

    if (i == 1) to = from;

    if (k > j) i += abs(31 - k);

    snprintf(date, 11, "%04u-%02u-%02u", from.Year(), from.Month(), from.Day());
    snprintf(FILE, 15, "%s.txt", date);

    file = sd.open(FILE, O_READ);
    if (file) {

      file.seek(47);

      while (file.available()) {
        memset(data, 0, sizeof(data));
        file.readBytes(data, 47);

        if (data[ 2] != ':')continue;
        if (data[ 5] != ':')continue;
        if (data[ 8] != ',')continue;
        if (data[17] != ',')continue;
        if (data[26] != ',')continue;
        if (data[35] != ',')continue;
        if (data[44] != ',')continue;

        counter_avg ++;

        memcpy(col1, data + 9, 8);
        memcpy(col2, data + 18, 8);
        memcpy(col3, data + 27, 8);
        memcpy(col4, data + 36, 8);

        sensor1_avg += atof(col1);
        sensor2_avg += atof(col2);
        sensor3_avg += atof(col3);
        sensor4_avg += atof(col4);
      }
      file.close();
    }
  }

  calc_ms_avg = millis() - calc_ms_avg;

  if (counter_avg) {
    sensor1_avg /= counter_avg;
    sensor2_avg /= counter_avg;
    sensor3_avg /= counter_avg;
    sensor4_avg /= counter_avg;
  }

  Serial.println(F("averages"));
  Serial.println(sensor1_avg);
  Serial.println(sensor2_avg);
  Serial.println(sensor3_avg);
  Serial.println(sensor4_avg);
  Serial.print(counter_avg);
  Serial.println(F(" counts"));
  Serial.print(calc_ms_avg);
  Serial.println(F(" ms"));
  Serial.println();
}