/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 * Copyright (C) 2003-2007 Imendio AB
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA  02110-1301  USA
 *
 * Authors: Richard Hult <richard@imendio.com>
 */

#include "config.h"
#include "datetime-internal.h"

#include <glib/gi18n.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>


/* Note: TplTime is always in UTC. */

time_t
_tpl_time_get_current (void)
{
  return time (NULL);
}

time_t
_tpl_time_get_local_time (struct tm *tm)
{
  const gchar *tz;
  time_t t;

  tz = g_getenv ("TZ");
  g_setenv ("TZ", "", TRUE);

  tzset ();

  t = mktime (tm);

  if (tz != NULL)
    g_setenv ("TZ", tz, TRUE);
  else
    g_unsetenv ("TZ");

  tzset ();

  return t;
}

/* The format is: "20021209T23:51:30" and is in UTC. 0 is returned on
 * failure. The alternative format "20021209" is also accepted.
 */
time_t
_tpl_time_parse (const gchar *str)
{
  struct tm tm;
  gint year, month;
  gint n_parsed;

  memset (&tm, 0, sizeof (struct tm));

  n_parsed = sscanf (str, "%4d%2d%2dT%2d:%2d:%2d",
      &year, &month, &tm.tm_mday, &tm.tm_hour,
      &tm.tm_min, &tm.tm_sec);
  if (n_parsed != 3 && n_parsed != 6)
    {
      return 0;
    }

  tm.tm_year = year - 1900;
  tm.tm_mon = month - 1;
  tm.tm_isdst = -1;

  return _tpl_time_get_local_time (&tm);
}

/* Converts the UTC timestamp to a string, also in UTC. Returns NULL on failure. */
gchar *
_tpl_time_to_string_utc (time_t t,
    const gchar * format)
{
  gchar stamp[128];
  struct tm *tm;

  g_return_val_if_fail (format != NULL, NULL);

  tm = gmtime (&t);
  if (strftime (stamp, sizeof (stamp), format, tm) == 0)
    {
      return NULL;
    }

  return g_strdup (stamp);
}

/* Converts the UTC timestamp to a string, in local time. Returns NULL on failure. */
gchar *
_tpl_time_to_string_local (time_t t,
    const gchar *format)
{
  gchar stamp[128];
  struct tm *tm;

  g_return_val_if_fail (format != NULL, NULL);

  tm = localtime (&t);
  if (strftime (stamp, sizeof (stamp), format, tm) == 0)
    {
      return NULL;
    }

  return g_strdup (stamp);
}

gchar *
_tpl_time_to_string_relative (time_t then)
{
  time_t now;
  gint seconds;

  now = time (NULL);
  seconds = now - then;

  if (seconds > 0)
    {
      if (seconds < 60)
        {
          return g_strdup_printf (ngettext ("%d second ago",
                "%d seconds ago", seconds),
              seconds);
        }
      else if (seconds < (60 * 60))
        {
          seconds /= 60;
          return g_strdup_printf (ngettext ("%d minute ago",
                "%d minutes ago", seconds),
              seconds);
        }
      else if (seconds < (60 * 60 * 24))
        {
          seconds /= 60 * 60;
          return g_strdup_printf (ngettext ("%d hour ago",
                "%d hours ago", seconds),
              seconds);
        }
      else if (seconds < (60 * 60 * 24 * 7))
        {
          seconds /= 60 * 60 * 24;
          return g_strdup_printf (ngettext ("%d day ago",
                "%d days ago", seconds), seconds);
        }
      else if (seconds < (60 * 60 * 24 * 30))
        {
          seconds /= 60 * 60 * 24 * 7;
          return g_strdup_printf (ngettext ("%d week ago",
                "%d weeks ago", seconds),
              seconds);
        }
      else
        {
          seconds /= 60 * 60 * 24 * 30;
          return g_strdup_printf (ngettext ("%d month ago",
                "%d months ago", seconds),
              seconds);
        }
    }
  else
    {
      return g_strdup (_("in the future"));
    }
}