/*
      This file is part of GNUnet
      (C) 2012-2013 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 peerstore/peerstore_common.c
 * @brief Helper peerstore functions
 * @author Omar Tarabai
 */

#include "peerstore_common.h"

/**
 * Creates a hash of the given key combination
 *
 */
void
PEERSTORE_hash_key(const char *sub_system,
    const struct GNUNET_PeerIdentity *peer,
    const char *key,
    struct GNUNET_HashCode *ret)
{
  size_t sssize;
  size_t psize;
  size_t ksize;
  size_t totalsize;
  void *block;
  void *blockptr;

  sssize = strlen(sub_system) + 1;
  psize = sizeof(struct GNUNET_PeerIdentity);
  ksize = strlen(key) + 1;
  totalsize = sssize + psize + ksize;
  block = GNUNET_malloc(totalsize);
  blockptr = block;
  memcpy(blockptr, sub_system, sssize);
  blockptr += sssize;
  memcpy(blockptr, peer, psize);
  blockptr += psize;
  memcpy(blockptr, key, ksize);
  GNUNET_CRYPTO_hash(block, totalsize, ret);
  GNUNET_free(block);
}

/**
 * Creates a record message ready to be sent
 *
 * @param sub_system sub system string
 * @param peer Peer identity (can be NULL)
 * @param key record key string (can be NULL)
 * @param value record value BLOB (can be NULL)
 * @param value_size record value size in bytes (set to 0 if value is NULL)
 * @param expiry absolute time after which the record expires
 * @param msg_type message type to be set in header
 * @return pointer to record message struct
 */
struct StoreRecordMessage *
PEERSTORE_create_record_message(const char *sub_system,
    const struct GNUNET_PeerIdentity *peer,
    const char *key,
    const void *value,
    size_t value_size,
    struct GNUNET_TIME_Absolute *expiry,
    uint16_t msg_type)
{
  struct StoreRecordMessage *srm;
  size_t ss_size;
  size_t key_size;
  size_t request_size;
  void *dummy;

  ss_size = strlen(sub_system) + 1;
  if(NULL == key)
    key_size = 0;
  else
    key_size = strlen(key) + 1;
  request_size = sizeof(struct StoreRecordMessage) +
      ss_size +
      key_size +
      value_size;
  srm = GNUNET_malloc(request_size);
  srm->header.size = htons(request_size);
  srm->header.type = htons(msg_type);
  srm->key_size = htons(key_size);
  if(NULL != expiry)
    srm->expiry = *expiry;
  if(NULL == peer)
    srm->peer_set = htons(GNUNET_NO);
  else
  {
    srm->peer_set = htons(GNUNET_YES);
    srm->peer = *peer;
  }
  srm->sub_system_size = htons(ss_size);
  srm->value_size = htons(value_size);
  dummy = &srm[1];
  memcpy(dummy, sub_system, ss_size);
  dummy += ss_size;
  memcpy(dummy, key, key_size);
  dummy += key_size;
  memcpy(dummy, value, value_size);
  return srm;

}

/**
 * Creates a MQ envelope for a single record
 *
 * @param sub_system sub system string
 * @param peer Peer identity (can be NULL)
 * @param key record key string (can be NULL)
 * @param value record value BLOB (can be NULL)
 * @param value_size record value size in bytes (set to 0 if value is NULL)
 * @param expiry time after which the record expires
 * @param msg_type message type to be set in header
 * @return pointer to record message struct
 */
struct GNUNET_MQ_Envelope *
PEERSTORE_create_record_mq_envelope(const char *sub_system,
    const struct GNUNET_PeerIdentity *peer,
    const char *key,
    const void *value,
    size_t value_size,
    struct GNUNET_TIME_Absolute *expiry,
    enum GNUNET_PEERSTORE_StoreOption options,
    uint16_t msg_type)
{
  struct StoreRecordMessage *srm;
  struct GNUNET_MQ_Envelope *ev;
  size_t ss_size;
  size_t key_size;
  size_t msg_size;
  void *dummy;

  GNUNET_assert(NULL != sub_system);
  ss_size = strlen(sub_system) + 1;
  if(NULL == key)
    key_size = 0;
  else
    key_size = strlen(key) + 1;
  msg_size = ss_size +
      key_size +
      value_size;
  ev = GNUNET_MQ_msg_extra(srm, msg_size, msg_type);
  srm->key_size = htons(key_size);
  if(NULL != expiry)
    srm->expiry = *expiry;
  if(NULL == peer)
    srm->peer_set = htons(GNUNET_NO);
  else
  {
    srm->peer_set = htons(GNUNET_YES);
    srm->peer = *peer;
  }
  srm->sub_system_size = htons(ss_size);
  srm->value_size = htons(value_size);
  srm->options = options;
  dummy = &srm[1];
  memcpy(dummy, sub_system, ss_size);
  dummy += ss_size;
  memcpy(dummy, key, key_size);
  dummy += key_size;
  memcpy(dummy, value, value_size);

  return ev;
}

/**
 * Parses a message carrying a record
 *
 * @param message the actual message
 * @return Pointer to record or NULL if error
 */
struct GNUNET_PEERSTORE_Record *
PEERSTORE_parse_record_message(const struct GNUNET_MessageHeader *message)
{
  struct StoreRecordMessage *srm;
  struct GNUNET_PEERSTORE_Record *record;
  uint16_t req_size;
  uint16_t ss_size;
  uint16_t key_size;
  uint16_t value_size;
  char *dummy;

  req_size = ntohs(message->size);
  if(req_size < sizeof(struct StoreRecordMessage))
    return NULL;
  srm = (struct StoreRecordMessage *)message;
  ss_size = ntohs(srm->sub_system_size);
  key_size = ntohs(srm->key_size);
  value_size = ntohs(srm->value_size);
  if(ss_size + key_size + value_size + sizeof(struct StoreRecordMessage)
        != req_size)
    return NULL;
  record = GNUNET_new(struct GNUNET_PEERSTORE_Record);
  if(GNUNET_YES == ntohs(srm->peer_set))
  {
    record->peer = GNUNET_new(struct GNUNET_PeerIdentity);
    memcpy(record->peer, &srm->peer, sizeof(struct GNUNET_PeerIdentity));
  }
  record->expiry = GNUNET_new(struct GNUNET_TIME_Absolute);
  *(record->expiry) = srm->expiry;
  dummy = (char *)&srm[1];
  if(ss_size > 0)
  {
    record->sub_system = GNUNET_strdup(dummy);
    dummy += ss_size;
  }
  if(key_size > 0)
  {
    record->key = GNUNET_strdup(dummy);
    dummy += key_size;
  }
  if(value_size > 0)
  {
    record->value = GNUNET_malloc(value_size);
    memcpy(record->value, dummy, value_size);
  }
  record->value_size = value_size;

  return record;
}

/**
 * Free any memory allocated for this record
 *
 * @param record
 */
void PEERSTORE_destroy_record(struct GNUNET_PEERSTORE_Record *record)
{
  if(NULL != record->sub_system)
    GNUNET_free(record->sub_system);
  if(NULL != record->peer)
    GNUNET_free(record->peer);
  if(NULL != record->key)
    GNUNET_free(record->key);
  if(NULL != record->value)
  {
    GNUNET_free(record->value);
    record->value = 0;
  }
  if(NULL != record->expiry)
    GNUNET_free(record->expiry);
  GNUNET_free(record);
}