// Simple date conversions and calculations

#include "RTClib.h"
//RTC_Millis rtc;

const char UBX_MSG_FMT[] = "$%s*%2X\n";
const char UBX_BAUD_STR[] = "PUBX,41,1,3,3,%d,0";
const char UBX_MSG_STR[] = "PUBX,40,%s,0,%d,0,0,0,0";

void showDate(const char* txt, const DateTime& dt) {
  Serial.printf("%s %04d/%02d/%02d %02d:%02d:%02d", txt, dt.year(), dt.month(), dt.day(), dt.hour(), dt.minute(), dt.second());
  Serial.printf(" = %ds / %dd since 1970\n", dt.unixtime(), dt.unixtime() / 86400L);
  Serial.println();
}

void showTimeSpan(const char* txt, const TimeSpan& ts) {
  Serial.printf("%s %d days %d hours %d minutes %d seconds (%d total seconds)\n", txt, ts.days(), ts.hours(), ts.minutes(), ts.seconds(), ts.totalseconds());

  Serial.println();
}

byte check_sum(char* buff, int len){
  byte cs = 0;
  for (int i = 0; i < len; i++) {
    cs = cs ^ byte(buff[i]);
  }
  return cs;
}

void send_ubx_msg(char* msg, byte state) {
  char buff[30];
  char buff2[30];
  int strSize = sprintf(buff, UBX_MSG_STR, msg, state);
  byte cs = check_sum(buff, strSize);
  Serial.printf(UBX_MSG_FMT, buff, cs);

}

void disable_NMEA_msg(char* msg) {
  send_ubx_msg(msg, 0);
}

void enable_NMEA_msg(char* msg) {
  send_ubx_msg(msg, 1);
}

void set_ubx_baudrate(uint32_t baud){
  char buff[30];
  int strSize = sprintf(buff, UBX_BAUD_STR, baud);
  byte cs = check_sum(buff, strSize);
  Serial.printf(UBX_MSG_FMT, buff, cs);

}

void setup () {
  Serial.begin(57600);

  delay(5000);

  //rtc.begin(DateTime(F(__DATE__), F(__TIME__)));

  // DateTime time = rtc.now();

  DateTime time (2026, 03, 03, 00, 48, 30);
  //Full Timestamp
  Serial.println(String("DateTime::TIMESTAMP_FULL:\t") + time.timestamp(DateTime::TIMESTAMP_FULL));

  //Date Only
  Serial.println(String("DateTime::TIMESTAMP_DATE:\t") + time.timestamp(DateTime::TIMESTAMP_DATE));

  //Full Timestamp
  Serial.println(String("DateTime::TIMESTAMP_TIME:\t") + time.timestamp(DateTime::TIMESTAMP_TIME));

  Serial.println("\n");

  DateTime pp = DateTime(1772501850);
  showDate("pp", pp);

  pp = DateTime(2021, 12, 25, 1, 2, 3);
  showDate("pp", pp);

  Serial.println("\n");
  DateTime dt6 (2026, 03, 03, 01, 37, 30);
  showDate("dt6", dt6);

  DateTime dt7 (dt6.unixtime() - 3 * 3600); // One hour later.
  showDate("dt7", dt7);

  DateTime dt75 = dt6 + TimeSpan(0, -3, 0, 0); // One hour later with TimeSpan addition.
  showDate("dt7.5", dt75);

  TimeSpan ts2 = dt7 - dt6;
  showTimeSpan("dt7-dt6", ts2);

  char pp2[] = "PUBX,41,1,3,3,57600,0";
  byte cs;
  for (int i = 0; i < (sizeof(pp2) - 1); i++) {
    cs = cs ^ byte(pp2[i]);
  }
  Serial.printf("$%s*%02X\n",pp2,cs);

  char pp3[] = "PUBX,40,RMC,0,0,0,0,0,0";
  cs=0;
  for (int i = 0; i < (sizeof(pp3) - 1); i++) {
    cs = cs ^ byte(pp3[i]);
  }
  Serial.printf("$%s*%02X\n",pp3,cs);

  char pp4[] = "PUBX,40,GSV,0,1,0,0,0,0";
  cs=0;
  for (int i = 0; i < (sizeof(pp4) - 1); i++) {
    cs = cs ^ byte(pp4[i]);
  }
  Serial.printf("$%s*%02X\n",pp4,cs);

  char ubxmsg[] = "PUBX,41,1,3,3,%d,0"; //$PUBX,41,1,3,3,115200,0*1C
  char buff[30];
  char buff2[30];
  int j = sprintf(buff,ubxmsg,115200);
  Serial.println(buff);
  cs=0;
  Serial.println(j/*sizeof(buff)*/);
  for (int i = 0; i < j; i++) {
    cs = cs ^ byte(buff[i]);
  }
  j = sprintf(buff2,"$%s*%02X\n",buff,cs);
  Serial.println(buff2);

  disable_NMEA_msg("RMC");
  disable_NMEA_msg("GGA");
  enable_NMEA_msg("RMC");

  set_ubx_baudrate(115200);
}

void loop () {
  delay(100);
}