/*
     This file is part of GNUnet
     (C) 2013 Christian Grothoff (and other contributing authors)

     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., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.
*/

/**
 * @file regex/plugin_block_regex.c
 * @brief blocks used for regex storage and search
 * @author Bartlomiej Polot
 */

#include "platform.h"
#include "gnunet_block_plugin.h"
#include "block_regex.h"
#include "regex_block_lib.h"

/**
 * Number of bits we set per entry in the bloomfilter.
 * Do not change!
 */
#define BLOOMFILTER_K 16


/**
 * Show debug info about outgoing edges from a block.
 * 
 * @param cls Closure (uunsed).
 * @param token Edge label.
 * @param len Length of @c token.
 * @param key Block the edge point to.
 * 
 * @return GNUNET_YES to keep iterating.
 */
static int
rdebug (void *cls,
             const char *token,
             size_t len,
             const struct GNUNET_HashCode *key)
{
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "    %s: %.*s\n",
              GNUNET_h2s (key), len, token);
  return GNUNET_YES;
}


/**
 * Function called to validate a reply or a request of type
 * GNUNET_BLOCK_TYPE_REGEX.
 * For request evaluation, pass "NULL" for the reply_block.
 * Note that it is assumed that the reply has already been
 * matched to the key (and signatures checked) as it would
 * be done with the "get_key" function.
 *
 * @param cls closure
 * @param type block type
 * @param query original query (hash)
 * @param bf pointer to bloom filter associated with query; possibly updated (!)
 * @param bf_mutator mutation value for bf
 * @param xquery extrended query data (can be NULL, depending on type)
 * @param xquery_size number of bytes in xquery
 * @param reply_block response to validate
 * @param reply_block_size number of bytes in reply block
 * @return characterization of result
 */
static enum GNUNET_BLOCK_EvaluationResult
evaluate_block_regex (void *cls, enum GNUNET_BLOCK_Type type,
                      const struct GNUNET_HashCode * query,
                      struct GNUNET_CONTAINER_BloomFilter **bf,
                      int32_t bf_mutator, const void *xquery,
                      size_t xquery_size, const void *reply_block,
                      size_t reply_block_size)
{
  if (NULL == reply_block) /* queries (GET) are always valid */
    return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
  if (0 != xquery_size)
  {
    const char *query;

    query = (const char *) xquery;
    if ('\0' != query[xquery_size - 1]) /* must be valid string */
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  "Block xquery not a valid string\n");
      return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
    }
  }
  else if (NULL != query) /* PUTs don't need xquery */
  {
    const struct RegexBlock *rblock = reply_block;

    GNUNET_break_op (0);
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Block with no xquery\n");
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "  key: %s, %u edges\n",
                GNUNET_h2s (&rblock->key), ntohl (rblock->n_edges));
    GNUNET_REGEX_block_iterate (rblock, reply_block_size, &rdebug, NULL);
    return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
  }
  switch (GNUNET_REGEX_block_check (reply_block,
                                    reply_block_size,
                                    xquery))
  {
    case GNUNET_SYSERR:
      GNUNET_break_op(0);
      return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
    case GNUNET_NO:
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                  "BLOCK XQUERY %s not accepted\n", xquery);
      return GNUNET_BLOCK_EVALUATION_RESULT_IRRELEVANT;
    default:
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                  "BLOCK XQUERY %s accepted\n", xquery);
      break;
  }
  if (NULL != bf)
  {
    struct GNUNET_HashCode chash;
    struct GNUNET_HashCode mhash;

    GNUNET_CRYPTO_hash (reply_block, reply_block_size, &chash);
    GNUNET_BLOCK_mingle_hash (&chash, bf_mutator, &mhash);
    if (NULL != *bf)
    {
      if (GNUNET_YES == GNUNET_CONTAINER_bloomfilter_test (*bf, &mhash))
        return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
    }
    else
    {
      *bf = GNUNET_CONTAINER_bloomfilter_init (NULL, 8, BLOOMFILTER_K);
    }
    GNUNET_CONTAINER_bloomfilter_add (*bf, &mhash);
  }
  return GNUNET_BLOCK_EVALUATION_OK_MORE;
}


/**
 * Function called to validate a reply or a request of type
 * GNUNET_BLOCK_TYPE_REGEX_ACCEPT.
 * For request evaluation, pass "NULL" for the reply_block.
 * Note that it is assumed that the reply has already been
 * matched to the key (and signatures checked) as it would
 * be done with the "get_key" function.
 *
 * @param cls closure
 * @param type block type
 * @param query original query (hash)
 * @param bf pointer to bloom filter associated with query; possibly updated (!)
 * @param bf_mutator mutation value for bf
 * @param xquery extrended query data (can be NULL, depending on type)
 * @param xquery_size number of bytes in xquery
 * @param reply_block response to validate
 * @param reply_block_size number of bytes in reply block
 * @return characterization of result
 */
static enum GNUNET_BLOCK_EvaluationResult
evaluate_block_regex_accept (void *cls, enum GNUNET_BLOCK_Type type,
                             const struct GNUNET_HashCode * query,
                             struct GNUNET_CONTAINER_BloomFilter **bf,
                             int32_t bf_mutator, const void *xquery,
                             size_t xquery_size, const void *reply_block,
                             size_t reply_block_size)
{
  if (0 != xquery_size)
  {
    GNUNET_break_op (0);
    return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
  }
  if (NULL == reply_block)
    return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
  if (sizeof (struct RegexAccept) != reply_block_size)
  {
    GNUNET_break_op(0);
    return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
  }
  if (NULL != bf)
  {
    struct GNUNET_HashCode chash;
    struct GNUNET_HashCode mhash;

    GNUNET_CRYPTO_hash (reply_block, reply_block_size, &chash);
    GNUNET_BLOCK_mingle_hash (&chash, bf_mutator, &mhash);
    if (NULL != *bf)
    {
      if (GNUNET_YES == GNUNET_CONTAINER_bloomfilter_test (*bf, &mhash))
        return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
    }
    else
    {
      *bf = GNUNET_CONTAINER_bloomfilter_init (NULL, 8, BLOOMFILTER_K);
    }
    GNUNET_CONTAINER_bloomfilter_add (*bf, &mhash);
  }
  return GNUNET_BLOCK_EVALUATION_OK_MORE;
}


/**
 * Function called to validate a reply or a request.  For
 * request evaluation, simply pass "NULL" for the reply_block.
 * Note that it is assumed that the reply has already been
 * matched to the key (and signatures checked) as it would
 * be done with the "get_key" function.
 *
 * @param cls closure
 * @param type block type
 * @param query original query (hash)
 * @param bf pointer to bloom filter associated with query; possibly updated (!)
 * @param bf_mutator mutation value for bf
 * @param xquery extrended query data (can be NULL, depending on type)
 * @param xquery_size number of bytes in xquery
 * @param reply_block response to validate
 * @param reply_block_size number of bytes in reply block
 * @return characterization of result
 */
static enum GNUNET_BLOCK_EvaluationResult
block_plugin_regex_evaluate (void *cls, enum GNUNET_BLOCK_Type type,
                             const struct GNUNET_HashCode * query,
                             struct GNUNET_CONTAINER_BloomFilter **bf,
                             int32_t bf_mutator, const void *xquery,
                             size_t xquery_size, const void *reply_block,
                             size_t reply_block_size)
{
  enum GNUNET_BLOCK_EvaluationResult result;

  switch (type)
  {
    case GNUNET_BLOCK_TYPE_REGEX:
      result = evaluate_block_regex (cls, type, query, bf, bf_mutator,
                                     xquery, xquery_size,
                                     reply_block, reply_block_size);
      break;

    case GNUNET_BLOCK_TYPE_REGEX_ACCEPT:
      result = evaluate_block_regex_accept (cls, type, query, bf, bf_mutator,
                                            xquery, xquery_size,
                                            reply_block, reply_block_size);
      break;

    default:
      result = GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
  }
  return result;
}


/**
 * Function called to obtain the key for a block.
 *
 * @param cls closure
 * @param type block type
 * @param block block to get the key for
 * @param block_size number of bytes in block
 * @param key set to the key (query) for the given block
 * @return GNUNET_OK on success, GNUNET_SYSERR if type not supported
 *         (or if extracting a key from a block of this type does not work)
 */
static int
block_plugin_regex_get_key (void *cls, enum GNUNET_BLOCK_Type type,
                            const void *block, size_t block_size,
                            struct GNUNET_HashCode * key)
{
  switch (type)
  {
    case GNUNET_BLOCK_TYPE_REGEX:
      GNUNET_assert (sizeof (struct RegexBlock) <= block_size);
      *key = ((struct RegexBlock *) block)->key;
      return GNUNET_OK;
    case GNUNET_BLOCK_TYPE_REGEX_ACCEPT:
      GNUNET_assert (sizeof (struct RegexAccept) <= block_size);
      *key = ((struct RegexAccept *) block)->key;
      return GNUNET_OK;
    default:
      GNUNET_break (0);
      return GNUNET_SYSERR;
  }
}


/**
 * Entry point for the plugin.
 */
void *
libgnunet_plugin_block_regex_init (void *cls)
{
  static enum GNUNET_BLOCK_Type types[] =
  {
    GNUNET_BLOCK_TYPE_REGEX,
    GNUNET_BLOCK_TYPE_REGEX_ACCEPT,
    GNUNET_BLOCK_TYPE_ANY       /* end of list */
  };
  struct GNUNET_BLOCK_PluginFunctions *api;

  api = GNUNET_malloc (sizeof (struct GNUNET_BLOCK_PluginFunctions));
  api->evaluate = &block_plugin_regex_evaluate;
  api->get_key = &block_plugin_regex_get_key;
  api->types = types;
  return api;
}


/**
 * Exit point from the plugin.
 */
void *
libgnunet_plugin_block_regex_done (void *cls)
{
  struct GNUNET_TRANSPORT_PluginFunctions *api = cls;

  GNUNET_free (api);
  return NULL;
}

/* end of plugin_block_regex.c */