/*
   This file is part of GNUnet
   Copyright (C) 2010-2015 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 reclaim-attribute/reclaim_attribute.c
 * @brief helper library to manage identity attributes
 * @author Martin Schanzenbach
 */
#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_reclaim_plugin.h"
#include "reclaim_attribute.h"


/**
 * Handle for a plugin
 */
struct Plugin
{
  /**
   * Name of the plugin
   */
  char *library_name;

  /**
   * Plugin API
   */
  struct GNUNET_RECLAIM_AttributePluginFunctions *api;
};


/**
 * Plugins
 */
static struct Plugin **attr_plugins;


/**
 * Number of plugins
 */
static unsigned int num_plugins;


/**
 * Init canary
 */
static int initialized;


/**
 * Add a plugin
 *
 * @param cls closure
 * @param library_name name of the API library
 * @param lib_ret the plugin API pointer
 */
static void
add_plugin (void *cls, const char *library_name, void *lib_ret)
{
  struct GNUNET_RECLAIM_AttributePluginFunctions *api = lib_ret;
  struct Plugin *plugin;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Loading attribute plugin `%s'\n",
              library_name);
  plugin = GNUNET_new (struct Plugin);
  plugin->api = api;
  plugin->library_name = GNUNET_strdup (library_name);
  GNUNET_array_append (attr_plugins, num_plugins, plugin);
}


/**
 * Load plugins
 */
static void
init ()
{
  if (GNUNET_YES == initialized)
    return;
  initialized = GNUNET_YES;
  GNUNET_PLUGIN_load_all (GNUNET_OS_project_data_gnunet (),
                          "libgnunet_plugin_reclaim_attribute_",
                          NULL,
                          &add_plugin,
                          NULL);
}


void RECLAIM_ATTRIBUTE_fini (void);

/**
 * Dual function to #init().
 */
void __attribute__ ((destructor))
RECLAIM_ATTRIBUTE_fini (void)
{
  struct Plugin *plugin;

  for (unsigned int i = 0; i < num_plugins; i++)
  {
    plugin = attr_plugins[i];
    GNUNET_break (NULL ==
                  GNUNET_PLUGIN_unload (plugin->library_name,
                                        plugin->api));
    GNUNET_free (plugin->library_name);
    GNUNET_free (plugin);
  }
  GNUNET_free (attr_plugins);
  attr_plugins = NULL;
}


/**
 * Convert a type name to the corresponding number
 *
 * @param typename name to convert
 * @return corresponding number, UINT32_MAX on error
 */
uint32_t
GNUNET_RECLAIM_attribute_typename_to_number (const char *typename)
{
  unsigned int i;
  struct Plugin *plugin;
  uint32_t ret;

  init ();
  for (i = 0; i < num_plugins; i++)
  {
    plugin = attr_plugins[i];
    if (UINT32_MAX !=
        (ret = plugin->api->typename_to_number (plugin->api->cls, typename)))
      return ret;
  }
  return UINT32_MAX;
}


/**
 * Convert a type number to the corresponding type string
 *
 * @param type number of a type
 * @return corresponding typestring, NULL on error
 */
const char *
GNUNET_RECLAIM_attribute_number_to_typename (uint32_t type)
{
  unsigned int i;
  struct Plugin *plugin;
  const char *ret;

  init ();
  for (i = 0; i < num_plugins; i++)
  {
    plugin = attr_plugins[i];
    if (NULL !=
        (ret = plugin->api->number_to_typename (plugin->api->cls, type)))
      return ret;
  }
  return NULL;
}


/**
 * Convert human-readable version of a 'claim' of an attribute to the binary
 * representation
 *
 * @param type type of the claim
 * @param s human-readable string
 * @param data set to value in binary encoding (will be allocated)
 * @param data_size set to number of bytes in @a data
 * @return #GNUNET_OK on success
 */
int
GNUNET_RECLAIM_attribute_string_to_value (uint32_t type,
                                          const char *s,
                                          void **data,
                                          size_t *data_size)
{
  unsigned int i;
  struct Plugin *plugin;

  init ();
  for (i = 0; i < num_plugins; i++)
  {
    plugin = attr_plugins[i];
    if (GNUNET_OK == plugin->api->string_to_value (plugin->api->cls,
                                                   type,
                                                   s,
                                                   data,
                                                   data_size))
      return GNUNET_OK;
  }
  return GNUNET_SYSERR;
}


/**
 * Convert the 'claim' of an attribute to a string
 *
 * @param type the type of attribute
 * @param data claim in binary encoding
 * @param data_size number of bytes in @a data
 * @return NULL on error, otherwise human-readable representation of the claim
 */
char *
GNUNET_RECLAIM_attribute_value_to_string (uint32_t type,
                                          const void *data,
                                          size_t data_size)
{
  unsigned int i;
  struct Plugin *plugin;
  char *ret;

  init ();
  for (i = 0; i < num_plugins; i++)
  {
    plugin = attr_plugins[i];
    if (NULL != (ret = plugin->api->value_to_string (plugin->api->cls,
                                                     type,
                                                     data,
                                                     data_size)))
      return ret;
  }
  return NULL;
}


struct GNUNET_RECLAIM_Attribute *
GNUNET_RECLAIM_attribute_new (const char *attr_name,
                              const struct
                              GNUNET_RECLAIM_Identifier *credential,
                              uint32_t type,
                              const void *data,
                              size_t data_size)
{
  struct GNUNET_RECLAIM_Attribute *attr;
  char *write_ptr;
  char *attr_name_tmp;

  attr_name_tmp = GNUNET_STRINGS_utf8_tolower (attr_name);

  attr = GNUNET_malloc (sizeof(struct GNUNET_RECLAIM_Attribute)
                        + strlen (attr_name_tmp) + 1 + data_size);
  if (NULL != credential)
    attr->credential = *credential;
  attr->type = type;
  attr->data_size = data_size;
  attr->flag = 0;
  write_ptr = (char *) &attr[1];
  GNUNET_memcpy (write_ptr, attr_name_tmp, strlen (attr_name_tmp) + 1);
  attr->name = write_ptr;
  write_ptr += strlen (attr->name) + 1;
  GNUNET_memcpy (write_ptr, data, data_size);
  attr->data = write_ptr;
  GNUNET_free (attr_name_tmp);
  return attr;
}


void
GNUNET_RECLAIM_attribute_list_add (
  struct GNUNET_RECLAIM_AttributeList *al,
  const char *attr_name,
  const struct GNUNET_RECLAIM_Identifier *credential,
  uint32_t type,
  const void *data,
  size_t data_size)
{
  struct GNUNET_RECLAIM_AttributeListEntry *ale;

  ale = GNUNET_new (struct GNUNET_RECLAIM_AttributeListEntry);
  ale->attribute =
    GNUNET_RECLAIM_attribute_new (attr_name, credential,
                                  type, data, data_size);
  GNUNET_CONTAINER_DLL_insert (al->list_head,
                               al->list_tail,
                               ale);
}


/**
 * Get required size for serialization buffer
 *
 * @param attrs the attribute list to serialize
 * @return the required buffer size
 */
size_t
GNUNET_RECLAIM_attribute_list_serialize_get_size (
  const struct GNUNET_RECLAIM_AttributeList *al)
{
  struct GNUNET_RECLAIM_AttributeListEntry *ale;
  size_t len = 0;

  for (ale = al->list_head; NULL != ale; ale = ale->next)
  {
    GNUNET_assert (NULL != ale->attribute);
    len += GNUNET_RECLAIM_attribute_serialize_get_size (ale->attribute);
  }
  return len;
}


size_t
GNUNET_RECLAIM_attribute_list_serialize (
  const struct GNUNET_RECLAIM_AttributeList *attrs,
  char *result)
{
  struct GNUNET_RECLAIM_AttributeListEntry *ale;
  size_t len;
  size_t total_len;
  char *write_ptr;
  write_ptr = result;
  total_len = 0;
  for (ale = attrs->list_head; NULL != ale; ale = ale->next)
  {
    GNUNET_assert (NULL != ale->attribute);
    len = GNUNET_RECLAIM_attribute_serialize (ale->attribute, write_ptr);
    total_len += len;
    write_ptr += len;
  }
  return total_len;
}


/**
 * Deserialize an attribute list
 *
 * @param data the serialized attribute list
 * @param data_size the length of the serialized data
 * @return a GNUNET_IDENTITY_PROVIDER_AttributeList, must be free'd by caller
 */
struct GNUNET_RECLAIM_AttributeList *
GNUNET_RECLAIM_attribute_list_deserialize (const char *data, size_t data_size)
{
  struct GNUNET_RECLAIM_AttributeList *al;
  struct GNUNET_RECLAIM_AttributeListEntry *ale;
  size_t attr_len;
  const char *read_ptr;
  size_t left = data_size;

  al = GNUNET_new (struct GNUNET_RECLAIM_AttributeList);
  if (data_size < sizeof(struct Attribute))
    return al;
  read_ptr = data;
  while (left >= sizeof(struct Attribute))
  {
    ale = GNUNET_new (struct GNUNET_RECLAIM_AttributeListEntry);
    attr_len =
      GNUNET_RECLAIM_attribute_deserialize (read_ptr,
                                            left,
                                            &ale->attribute);
    if (-1 == attr_len)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                  "Failed to deserialize malformed attribute.\n");
      GNUNET_free (ale);
      return al;
    }
    left -= attr_len;
    GNUNET_CONTAINER_DLL_insert (al->list_head, al->list_tail, ale);
    read_ptr += attr_len;
  }
  return al;
}


struct GNUNET_RECLAIM_AttributeList *
GNUNET_RECLAIM_attribute_list_dup (
  const struct GNUNET_RECLAIM_AttributeList *attrs)
{
  struct GNUNET_RECLAIM_AttributeListEntry *ale;
  struct GNUNET_RECLAIM_AttributeListEntry *result_ale;
  struct GNUNET_RECLAIM_AttributeList *result;

  result = GNUNET_new (struct GNUNET_RECLAIM_AttributeList);
  for (ale = attrs->list_head; NULL != ale; ale = ale->next)
  {
    result_ale = GNUNET_new (struct GNUNET_RECLAIM_AttributeListEntry);
    GNUNET_assert (NULL != ale->attribute);
    {
      result_ale->attribute =
        GNUNET_RECLAIM_attribute_new (ale->attribute->name,
                                      &ale->attribute->credential,
                                      ale->attribute->type,
                                      ale->attribute->data,
                                      ale->attribute->data_size);

      result_ale->attribute->id = ale->attribute->id;
      result_ale->attribute->flag = ale->attribute->flag;
    }
    GNUNET_CONTAINER_DLL_insert (result->list_head,
                                 result->list_tail,
                                 result_ale);
  }
  return result;
}


void
GNUNET_RECLAIM_attribute_list_destroy (
  struct GNUNET_RECLAIM_AttributeList *al)
{
  struct GNUNET_RECLAIM_AttributeListEntry *ale;
  struct GNUNET_RECLAIM_AttributeListEntry *tmp_ale;

  for (ale = al->list_head; NULL != ale;)
  {
    if (NULL != ale->attribute)
      GNUNET_free (ale->attribute);
    tmp_ale = ale;
    ale = ale->next;
    GNUNET_free (tmp_ale);
  }
  GNUNET_free (al);
}


/**
 * Get required size for serialization buffer
 *
 * @param attr the attribute to serialize
 * @return the required buffer size
 */
size_t
GNUNET_RECLAIM_attribute_serialize_get_size (
  const struct GNUNET_RECLAIM_Attribute *attr)
{
  return sizeof(struct Attribute) + strlen (attr->name) + attr->data_size;
}


/**
 * Serialize an attribute
 *
 * @param attr the attribute to serialize
 * @param result the serialized attribute
 * @return length of serialized data
 */
size_t
GNUNET_RECLAIM_attribute_serialize (
  const struct GNUNET_RECLAIM_Attribute *attr,
  char *result)
{
  size_t data_len_ser;
  size_t name_len;
  struct Attribute *attr_ser;
  char *write_ptr;

  attr_ser = (struct Attribute *) result;
  attr_ser->attribute_type = htonl (attr->type);
  attr_ser->attribute_flag = htonl (attr->flag);
  attr_ser->attribute_id = attr->id;
  attr_ser->credential_id = attr->credential;
  name_len = strlen (attr->name);
  attr_ser->name_len = htons (name_len);
  write_ptr = (char *) &attr_ser[1];
  GNUNET_memcpy (write_ptr, attr->name, name_len);
  write_ptr += name_len;
  // TODO plugin-ize
  // data_len_ser = plugin->serialize_attribute_value (attr,
  //                                                  &attr_ser[1]);
  data_len_ser = attr->data_size;
  GNUNET_memcpy (write_ptr, attr->data, attr->data_size);
  attr_ser->data_size = htons (data_len_ser);

  return sizeof(struct Attribute) + strlen (attr->name) + attr->data_size;
}


/**
 * Deserialize an attribute
 *
 * @param data the serialized attribute
 * @param data_size the length of the serialized data
 *
 * @return a GNUNET_IDENTITY_PROVIDER_Attribute, must be free'd by caller
 */
ssize_t
GNUNET_RECLAIM_attribute_deserialize (const char *data, size_t data_size,
                                      struct GNUNET_RECLAIM_Attribute **attr)
{
  struct Attribute *attr_ser;
  struct GNUNET_RECLAIM_Attribute *attribute;
  size_t data_len;
  size_t name_len;
  char *write_ptr;

  if (data_size < sizeof(struct Attribute))
    return -1;

  attr_ser = (struct Attribute *) data;
  data_len = ntohs (attr_ser->data_size);
  name_len = ntohs (attr_ser->name_len);
  if (data_size < sizeof(struct Attribute) + data_len + name_len)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Buffer too small to deserialize\n");
    return -1;
  }
  attribute = GNUNET_malloc (sizeof(struct GNUNET_RECLAIM_Attribute)
                             + data_len + name_len + 1);
  attribute->type = ntohl (attr_ser->attribute_type);
  attribute->flag = ntohl (attr_ser->attribute_flag);
  attribute->id = attr_ser->attribute_id;
  attribute->credential = attr_ser->credential_id;
  attribute->data_size = data_len;

  write_ptr = (char *) &attribute[1];
  GNUNET_memcpy (write_ptr, &attr_ser[1], name_len);
  write_ptr[name_len] = '\0';
  attribute->name = write_ptr;

  write_ptr += name_len + 1;
  GNUNET_memcpy (write_ptr, (char *) &attr_ser[1] + name_len,
                 attribute->data_size);
  *attr = attribute;
  attribute->data = write_ptr;
  return sizeof(struct Attribute) + data_len + name_len;
}


/* end of reclaim_attribute.c */
