/* Copyright JS Foundation and other contributors, http://js.foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "jerryscript-port.h"

#if defined(__unix__) || defined(__APPLE__)

#include <sys/time.h>
#include <time.h>

/**
 * Default implementation of jerry_port_local_tza.
 *
 * @return offset between UTC and local time at the given unix timestamp, if
 *         available. Otherwise, returns 0, assuming UTC time.
 */
int32_t
jerry_port_local_tza (double unix_ms)
{
  time_t time = (time_t) unix_ms / 1000;

#if defined(HAVE_TM_GMTOFF)
  struct tm tm;
  localtime_r (&time, &tm);

  return ((int32_t) tm.tm_gmtoff) * 1000;
#else /* !defined(HAVE_TM_GMTOFF) */
  struct tm gmt_tm;
  struct tm local_tm;

  gmtime_r (&time, &gmt_tm);
  localtime_r (&time, &local_tm);

  time_t gmt = mktime (&gmt_tm);

  /* mktime removes the daylight saving time from the result time value, however we want to keep it */
  local_tm.tm_isdst = 0;
  time_t local = mktime (&local_tm);

  return (int32_t) difftime (local, gmt) * 1000;
#endif /* HAVE_TM_GMTOFF */
} /* jerry_port_local_tza */

/**
 * Default implementation of jerry_port_current_time.
 *
 * @return milliseconds since Unix epoch
 */
double
jerry_port_current_time (void)
{
  struct timeval tv;
  gettimeofday (&tv, NULL);

  return ((double) tv.tv_sec) * 1000.0 + ((double) tv.tv_usec) / 1000.0;
} /* jerry_port_current_time */

#endif /* defined(__unix__) || defined(__APPLE__) */