/*
     This file is part of GNUnet
     Copyright (C) 2012, 2013, 2016 GNUnet e.V.

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     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
     Affero General Public License for more details.

     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */
/**
 * @file regex/regex_api_announce.c
 * @brief access regex service to advertise capabilities via regex
 * @author Maximilian Szengel
 * @author Christian Grothoff
 */
#include "platform.h"
#include "gnunet_protocols.h"
#include "gnunet_util_lib.h"
#include "gnunet_regex_service.h"
#include "regex_ipc.h"

#define LOG(kind, ...) GNUNET_log_from(kind, "regex-api", __VA_ARGS__)

/**
 * Handle to store cached data about a regex announce.
 */
struct GNUNET_REGEX_Announcement {
  /**
   * Connection to the regex service.
   */
  struct GNUNET_MQ_Handle *mq;

  /**
   * Our configuration.
   */
  const struct GNUNET_CONFIGURATION_Handle *cfg;

  /**
   * Message we're sending to the service.
   */
  char *regex;

  /**
   * Frequency of announcements.
   */
  struct GNUNET_TIME_Relative refresh_delay;

  /**
   * Number of characters per edge.
   */
  uint16_t compression;
};



/**
 * (Re)connect to the REGEX service with the given announcement @a a.
 *
 * @param a REGEX to announce.
 */
static void
announce_reconnect(struct GNUNET_REGEX_Announcement *a);


/**
 * We got a disconnect after asking regex to do the announcement.
 * Retry.
 *
 * @param cls the `struct GNUNET_REGEX_Announcement` to retry
 * @param error error code
 */
static void
announce_mq_error_handler(void *cls,
                          enum GNUNET_MQ_Error error)
{
  struct GNUNET_REGEX_Announcement *a = cls;

  GNUNET_MQ_destroy(a->mq);
  a->mq = NULL;
  announce_reconnect(a);
}


/**
 * (Re)connect to the REGEX service with the given announcement @a a.
 *
 * @param a REGEX to announce.
 */
static void
announce_reconnect(struct GNUNET_REGEX_Announcement *a)
{
  struct GNUNET_MQ_Envelope *env;
  struct AnnounceMessage *am;
  size_t slen;

  a->mq = GNUNET_CLIENT_connect(a->cfg,
                                "regex",
                                NULL,
                                &announce_mq_error_handler,
                                a);
  if (NULL == a->mq)
    return;
  slen = strlen(a->regex) + 1;
  env = GNUNET_MQ_msg_extra(am,
                            slen,
                            GNUNET_MESSAGE_TYPE_REGEX_ANNOUNCE);
  am->compression = htons(a->compression);
  am->reserved = htons(0);
  am->refresh_delay = GNUNET_TIME_relative_hton(a->refresh_delay);
  GNUNET_memcpy(&am[1],
                a->regex,
                slen);
  GNUNET_MQ_send(a->mq,
                 env);
}


/**
 * Announce the given peer under the given regular expression.
 *
 * @param cfg configuration to use
 * @param regex Regular expression to announce.
 * @param refresh_delay after what delay should the announcement be repeated?
 * @param compression How many characters per edge can we squeeze?
 * @return Handle to reuse o free cached resources.
 *         Must be freed by calling #GNUNET_REGEX_announce_cancel().
 */
struct GNUNET_REGEX_Announcement *
GNUNET_REGEX_announce(const struct GNUNET_CONFIGURATION_Handle *cfg,
                      const char *regex,
                      struct GNUNET_TIME_Relative refresh_delay,
                      uint16_t compression)
{
  struct GNUNET_REGEX_Announcement *a;
  size_t slen;

  slen = strlen(regex) + 1;
  if (slen + sizeof(struct AnnounceMessage) >= GNUNET_MAX_MESSAGE_SIZE)
    {
      GNUNET_log(GNUNET_ERROR_TYPE_WARNING,
                 _("Regex `%s' is too long!\n"),
                 regex);
      GNUNET_break(0);
      return NULL;
    }
  a = GNUNET_new(struct GNUNET_REGEX_Announcement);
  a->cfg = cfg;
  a->refresh_delay = refresh_delay;
  a->compression = compression;
  a->regex = GNUNET_strdup(regex);
  announce_reconnect(a);
  if (NULL == a->mq)
    {
      GNUNET_free(a->regex);
      GNUNET_free(a);
      return NULL;
    }
  return a;
}


/**
 * Stop announcing the regex specified by the given handle.
 *
 * @param a handle returned by a previous #GNUNET_REGEX_announce() call.
 */
void
GNUNET_REGEX_announce_cancel(struct GNUNET_REGEX_Announcement *a)
{
  GNUNET_MQ_destroy(a->mq);
  GNUNET_free(a->regex);
  GNUNET_free(a);
}

/* end of regex_api_announce.c */