/*
  Copyright (C) 2009-2016  Brazil
  Copyright (C) 2020-2022  Sutou Kouhei <kou@clear-code.com>

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include "grn_time.h"
#include "grn_ctx.h"
#include "grn_str.h"

#include <math.h>
#include <stdio.h>
#include <time.h>

#if defined(HAVE__LOCALTIME64_S) && defined(__GNUC__)
# ifdef _WIN64
#  define localtime_s(tm, time) _localtime64_s(tm, time)
# else /* _WIN64 */
#  define localtime_s(tm, time) _localtime32_s(tm, time)
# endif /* _WIN64 */
#endif /* defined(HAVE__LOCALTIME64_S) && defined(__GNUC__) */

/* fixme by 2038 */

grn_rc
grn_timeval_now(grn_ctx *ctx, grn_timeval *tv)
{
#ifdef WIN32
  struct __timeb64 tb;
  _ftime64_s(&tb);
  tv->tv_sec = tb.time;
  tv->tv_nsec = tb.millitm * (GRN_TIME_NSEC_PER_SEC / 1000);
  return GRN_SUCCESS;
#else /* WIN32 */
# ifdef HAVE_CLOCK_GETTIME
  struct timespec t;
  if (clock_gettime(CLOCK_REALTIME, &t)) {
    SERR("clock_gettime");
  } else {
    tv->tv_sec = t.tv_sec;
    tv->tv_nsec = (int32_t)(t.tv_nsec);
  }
  return ctx->rc;
# else /* HAVE_CLOCK_GETTIME */
  struct timeval t;
  if (gettimeofday(&t, NULL)) {
    SERR("gettimeofday");
  } else {
    tv->tv_sec = t.tv_sec;
    tv->tv_nsec = GRN_TIME_USEC_TO_NSEC(t.tv_usec);
  }
  return ctx->rc;
# endif /* HAVE_CLOCK_GETTIME */
#endif /* WIN32 */
}

grn_timeval
grn_timeval_from_double(grn_ctx *ctx, double value)
{
  grn_timeval timeval;
  double sec = trunc(value);
  timeval.tv_sec = (int64_t)sec;
  timeval.tv_nsec =
    (int32_t)(
      ((int64_t)((value - (double)(timeval.tv_sec)) * GRN_TIME_NSEC_PER_SEC) %
       GRN_TIME_NSEC_PER_SEC));
  return timeval;
}

void
grn_time_now(grn_ctx *ctx, grn_obj *obj)
{
  grn_timeval tv;
  grn_timeval_now(ctx, &tv);
  GRN_TIME_SET(ctx, obj, GRN_TIME_PACK(tv.tv_sec,
                                       GRN_TIME_NSEC_TO_USEC(tv.tv_nsec)));
}

static bool
grn_time_t_to_tm(grn_ctx *ctx, const grn_time_t time, struct tm *tm)
{
  bool success;
  const char *function_name;
#ifdef HAVE__LOCALTIME64_S
  function_name = "localtime_s";
  success = (_localtime64_s(tm, &time) == 0);
#else /* HAVE__LOCALTIME64_S */
# ifdef HAVE_LOCALTIME_R
  function_name = "localtime_r";
  success = (localtime_r(&time, tm) != NULL);
# else /* HAVE_LOCALTIME_R */
  function_name = "localtime";
  {
    struct tm *local_tm;
    local_tm = localtime(&time);
    if (local_tm) {
      success = true;
      memcpy(tm, local_tm, sizeof(struct tm));
    } else {
      success = false;
    }
  }
# endif /* HAVE_LOCALTIME_R */
#endif /* HAVE__LOCALTIME64_S */
  if (!success) {
    SERR("%s: failed to convert time_t to struct tm: <%" GRN_FMT_INT64D ">",
         function_name,
         (int64_t)time);
  }
  return success;
}

struct tm *
grn_timeval2tm(grn_ctx *ctx, grn_timeval *tv, struct tm *tm)
{
  if (grn_time_t_to_tm(ctx, tv->tv_sec, tm)) {
    return tm;
  } else {
    return NULL;
  }
}

bool
grn_time_to_tm(grn_ctx *ctx, int64_t time, struct tm *tm)
{
  int64_t sec;
  int32_t usec;

  GRN_TIME_UNPACK(time, sec, usec);
  return grn_time_t_to_tm(ctx, sec, tm);
}

static bool
grn_time_t_from_tm(grn_ctx *ctx, grn_time_t *time, struct tm *tm)
{
  tm->tm_yday = -1;
  *time = grn_mktime(tm);
  /* We can't use (*time != -1) because -1 is a valid UNIX time
   * (1969-12-31T23:59:59Z). */
  bool success = (tm->tm_yday != -1);
  if (!success) {
    ERR(GRN_INVALID_ARGUMENT,
        "mktime: failed to convert struct tm to time_t: "
        "<%04d-%02d-%02dT%02d:%02d:%02d>(%d)",
        1900 + tm->tm_year,
        tm->tm_mon + 1,
        tm->tm_mday,
        tm->tm_hour,
        tm->tm_min,
        tm->tm_sec,
        tm->tm_isdst);
  }
  return success;
}

bool
grn_time_from_tm(grn_ctx *ctx, int64_t *time, struct tm *tm)
{
  grn_time_t sec_time_t;
  int64_t sec;
  int32_t usec = 0;

  if (!grn_time_t_from_tm(ctx, &sec_time_t, tm)) {
    return false;
  }

  sec = sec_time_t;
  *time = GRN_TIME_PACK(sec, usec);
  return true;
}

grn_rc
grn_timeval2str(grn_ctx *ctx, grn_timeval *tv, char *buf, size_t buf_size)
{
  struct tm tm;
  struct tm *ltm;
  ltm = grn_timeval2tm(ctx, tv, &tm);
  grn_snprintf(buf, buf_size, GRN_TIMEVAL_STR_SIZE,
               GRN_TIMEVAL_STR_FORMAT,
               ltm->tm_year + 1900, ltm->tm_mon + 1, ltm->tm_mday,
               ltm->tm_hour, ltm->tm_min, ltm->tm_sec,
               (int)(GRN_TIME_NSEC_TO_USEC(tv->tv_nsec)));
  if (buf_size > GRN_TIMEVAL_STR_SIZE) {
    buf[GRN_TIMEVAL_STR_SIZE - 1] = '\0';
  } else {
    buf[buf_size - 1] = '\0';
  }
  return ctx->rc;
}

static grn_rc
grn_str2timeval_offset_sec(const char *start, const char *end, bool *have_offset, int32_t *gm_offset_sec)
{
  const char *position = start;
  int32_t hours, minutes = 0, sign = 1;

  *have_offset = false;
  *gm_offset_sec = 0;

  if (position >= end) { return GRN_SUCCESS; }

  switch (*position) {
  case '+' :
    sign = 1;
    *have_offset = true;
    break;
  case '-' :
    sign = -1;
    *have_offset = true;
    break;
  case 'Z' :
  case 'z' :
    *have_offset = true;
    return GRN_SUCCESS;
  default :
    return GRN_INVALID_ARGUMENT;
  }

  position++;
  if (position >= end) { return GRN_INVALID_ARGUMENT; }

  hours = grn_atoi(position, end, &position);
  if (hours < 0 || hours >= 24) { return GRN_INVALID_ARGUMENT; }

  if (position < end && *position == ':') {
    position++;
    if (position == end) { return GRN_INVALID_ARGUMENT; }

    minutes = grn_atoi(position, end, &position);
    if (minutes < 0 || minutes >= 60) { return GRN_INVALID_ARGUMENT; }
  }

  *gm_offset_sec = sign * (hours * 3600 + minutes * 60);

  return GRN_SUCCESS;
}

grn_rc
grn_str2timeval(const char *str, uint32_t str_len, grn_timeval *tv)
{
  struct tm tm;
  const char *r1, *r2, *rend = str + str_len;
  uint32_t uv = 0;

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

  tm.tm_year = (int)grn_atoui(str, rend, &r1) - 1900;
  if ((r1 + 1) >= rend || (*r1 != '/' && *r1 != '-')) {
    return GRN_INVALID_ARGUMENT;
  }
  r1++;
  tm.tm_mon = (int)grn_atoui(r1, rend, &r1) - 1;
  if ((r1 + 1) >= rend || (*r1 != '/' && *r1 != '-') ||
      tm.tm_mon < 0 || tm.tm_mon >= 12) { return GRN_INVALID_ARGUMENT; }
  r1++;
  tm.tm_mday = (int)grn_atoui(r1, rend, &r1);
  if (tm.tm_mday < 1 || tm.tm_mday > 31) {
    return GRN_INVALID_ARGUMENT;
  }
  if (r1 == rend) {
    /* YYYY-MM-DD */
    r2 = r1;
  } else {
    /* YYYY-MM-DD[ Tt]hh:mm:ss */
    if ((r1 + 1) >= rend || (*r1 != ' ' && *r1 != 'T' && *r1 != 't')) {
      return GRN_INVALID_ARGUMENT;
    }

    tm.tm_hour = (int)grn_atoui(++r1, rend, &r2);
    if ((r2 + 1) >= rend || r1 == r2 || *r2 != ':' ||
        tm.tm_hour < 0 || tm.tm_hour >= 24) {
      return GRN_INVALID_ARGUMENT;
    }
    r1 = r2 + 1;
    tm.tm_min = (int)grn_atoui(r1, rend, &r2);
    if ((r2 + 1) >= rend || r1 == r2 || *r2 != ':' ||
        tm.tm_min < 0 || tm.tm_min >= 60) {
      return GRN_INVALID_ARGUMENT;
    }
    r1 = r2 + 1;
    tm.tm_sec = (int)grn_atoui(r1, rend, &r2);
    if (r1 == r2 ||
        tm.tm_sec < 0 || tm.tm_sec > 61 /* leap 2sec */) {
      return GRN_INVALID_ARGUMENT;
    }
    r1 = r2;

    if ((r1 + 1) < rend && *r1 == '.') {
      /* YYYY-MM-DD[ Tt]hh:mm:ss.UUUUUU */
      uv = grn_atoui(++r1, rend, &r2);

      for (int i = 0; r2 + i < r1 + 6; i++) {
        uv *= 10;
      }
      if (uv >= GRN_TIME_USEC_PER_SEC) { return GRN_INVALID_ARGUMENT; }
    }
  }

  tm.tm_yday = -1;
  tm.tm_isdst = -1;

  {
    bool have_offset = false;
    int32_t gm_offset_sec = 0;
    grn_rc rc = GRN_SUCCESS;

    rc = grn_str2timeval_offset_sec(r2, rend, &have_offset, &gm_offset_sec);

    if (rc != GRN_SUCCESS) { return rc; }

    if (have_offset) {
      tv->tv_sec = grn_timegm(&tm);
      tv->tv_sec -= gm_offset_sec;
    } else {
      tv->tv_sec = grn_mktime(&tm);
    }
    /* tm_yday is set appropriately (0-365) on successful completion. */
    if (tm.tm_yday == -1) { return GRN_INVALID_ARGUMENT; }
  }

  tv->tv_nsec = (int32_t)GRN_TIME_USEC_TO_NSEC(uv);
  return GRN_SUCCESS;
}