/*
     This file is part of GNUnet.
     Copyright (C) 2011-2013 GNUnet e.V.

     GNUnet 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 3, or (at your
     option) any later version.

     GNUnet 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 GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
*/

/**
 * @file util/speedup.c
 * @author Matthias Wachs
 * @brief functions to speedup peer execution by manipulation system time
 */
#include "platform.h"
#include "gnunet_util_lib.h"
#include "speedup.h"

#define LOG(kind,...) GNUNET_log_from (kind, "util-speedup", __VA_ARGS__)


static struct GNUNET_TIME_Relative interval;

static struct GNUNET_TIME_Relative delta;

static struct GNUNET_SCHEDULER_Task *speedup_task;


static void
do_speedup (void *cls)
{
  static long long current_offset;

  (void) cls;
  speedup_task = NULL;
  current_offset += delta.rel_value_us;
  GNUNET_TIME_set_offset (current_offset);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Speeding up execution time by %s\n",
       GNUNET_STRINGS_relative_time_to_string (delta, GNUNET_NO));
  speedup_task = GNUNET_SCHEDULER_add_delayed (interval,
					       &do_speedup,
					       NULL);
}


/**
 * Start task that may speed up our system clock artificially
 *
 * @param cfg configuration to use
 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the speedup was not configured
 */
int
GNUNET_SPEEDUP_start_ (const struct GNUNET_CONFIGURATION_Handle *cfg)
{
  GNUNET_assert (NULL == speedup_task);
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_time (cfg,
					   "testing",
                                           "SPEEDUP_INTERVAL",
					   &interval))
    return GNUNET_SYSERR;
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_time (cfg,
					   "testing",
                                           "SPEEDUP_DELTA",
					   &delta))
    return GNUNET_SYSERR;

  if ( (0 == interval.rel_value_us) ||
       (0 == delta.rel_value_us) )
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
	 "Speed up disabled\n");
    return GNUNET_OK;
  }
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Speed up execution by %s\n",
       GNUNET_STRINGS_relative_time_to_string (delta, GNUNET_NO));
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Speed up executed every %s\n",
       GNUNET_STRINGS_relative_time_to_string (interval, GNUNET_NO));
  speedup_task = GNUNET_SCHEDULER_add_now_with_lifeness (GNUNET_NO,
                                                         &do_speedup,
							 NULL);
  return GNUNET_OK;
}


/**
 * Stop tasks that modify clock behavior.
 */
void
GNUNET_SPEEDUP_stop_ ()
{
  if (NULL != speedup_task)
  {
    GNUNET_SCHEDULER_cancel (speedup_task);
    speedup_task = NULL;
  }
  if ( (0 != interval.rel_value_us) &&
       (0 != delta.rel_value_us) )
    LOG (GNUNET_ERROR_TYPE_DEBUG,
	 "Stopped execution speed up\n");
}

/* end of speedup.c */
