// Copyright (C) 2007 Zack Weinberg <zackw@panix.com>
//
// This program is made available under the GNU GPL version 2.0 or
// greater. See the accompanying file COPYING for details.
//
// This program is distributed WITHOUT ANY WARRANTY; without even the
// implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
// PURPOSE.

#ifndef DATES_HH
#define DATES_HH

// This file provides a straightforward wrapper class around the standard
// C time functions.  Note that all operations are done in UTC, *not* the
// user's time zone.

#include "numeric_vocab.hh"
#include "sanity.hh"

struct date_t
{
  // For the benefit of the --date option.
  date_t() : d("") {}
  bool valid() const { return d != ""; }

  // Return the local system's idea of the current date.
  static date_t now();

  // Return the date corresponding to an unsigned 64-bit count of seconds
  // since the Unix epoch (1970-01-01T00:00:00).
  static date_t from_unix_epoch(u64);

  // Return the date corresponding to a string.  Presently this recognizes
  // only ISO 8601 "basic" and "extended" time formats.
  static date_t from_string(std::string const &);

  // Write out date as a string.
  std::string const & as_iso_8601_extended() const;

  // Write out date as an unsigned 64-bit count of seconds.
  u64 as_unix_epoch() const;

private:
  // For what we do with dates, it is most convenient to store them as
  // strings in the ISO 8601 extended time format.
  std::string d;

  // used by the above factory functions
  date_t(std::string const & s) : d(s) {};
};

std::ostream & operator<< (std::ostream & o, date_t const & d);
template <> void dump(date_t const & d, std::string & s);

#endif // dates.hh

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// mode: C++
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// c-file-style: "gnu"
// indent-tabs-mode: nil
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