#ifndef _DATETIME_HELPERS_H_
#define _DATETIME_HELPERS_H_

#include <time.h>
#include <sstream>

/// \brief Date-time utility methods
class DateTimeHelpers
{
public:

  /// \brief Create a unix timestamp from individual time components.
  static time_t MKTimestamp(int year, int month, int day, int hour, int min, int sec)
  {
    time_t rawtime;
    struct tm * timeinfo;

    time(&rawtime);
    timeinfo = gmtime(&rawtime);                // NOLINT(runtime/threadsafe_fn)
    timeinfo->tm_year = year - 1900;
    timeinfo->tm_mon = month - 1;
    timeinfo->tm_mday = day;
    timeinfo->tm_hour = hour;
    timeinfo->tm_min = min;
    timeinfo->tm_sec = sec;
    timeinfo->tm_isdst = 0; // disable daylight saving time

    time_t ret = mktime(timeinfo);

    return ret;
  }

  static time_t GetGMTTimestamp()
  {
    time_t rawTime = 0;
    time(&rawTime);
    struct tm* pTm;
    pTm = gmtime(&rawTime);     // NOLINT(runtime/threadsafe_fn)
    return mktime(pTm);
  }

  /// \brief Parse unix time from a string in the form yyyy-mm-dd hh:mm:ss (ex: 2015-11-16 09:43:36Z)
  static time_t GetDateTime(const std::string pstr)
  {
    // yyyy-mm-dd hh:mm:ss
    // example 2015-11-16 09:43:36Z
    int m, d, y, h, min, sec;
    std::istringstream istr(pstr);

    istr >> y;
    istr.ignore();
    istr >> m;
    istr.ignore();
    istr >> d;
    istr.ignore();
    istr >> h;
    istr.ignore();
    istr >> min;
    istr.ignore();
    istr >> sec;
    time_t t;

    t = MKTimestamp(y, m, d, h, min, sec);
    return t;
  }
};

#endif  // _DATETIME_HELPERS_H_