/*
   This file is part of GNUnet.
   Copyright (C) 2012-2015 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
   */
/**
 * @author Martin Schanzenbach
 * @author Philippe Buschmann
 * @file namestore/plugin_rest_namestore.c
 * @brief GNUnet Namestore REST plugin
 */

#include "platform.h"
#include "gnunet_rest_plugin.h"
#include "gnunet_gns_service.h"
#include "gnunet_namestore_service.h"
#include "gnunet_identity_service.h"
#include "gnunet_rest_lib.h"
#include "gnunet_json_lib.h"
#include "microhttpd.h"
#include <jansson.h>

/**
 * Namestore Namespace
 */
#define GNUNET_REST_API_NS_NAMESTORE "/namestore"

/**
 * Error message Unknown Error
 */
#define GNUNET_REST_NAMESTORE_ERROR_UNKNOWN "Unknown Error"

/**
 * Error message No identity found
 */
#define GNUNET_REST_IDENTITY_NOT_FOUND "No identity found"

/**
 * Error message No default zone specified
 */
#define GNUNET_REST_NAMESTORE_NO_DEFAULT_ZONE "No default zone specified"

/**
 * Error message Failed request
 */
#define GNUNET_REST_NAMESTORE_FAILED "Namestore action failed"

/**
 * Error message invalid data
 */
#define GNUNET_REST_NAMESTORE_INVALID_DATA "Data invalid"

/**
 * Error message No data
 */
#define GNUNET_REST_NAMESTORE_NO_DATA "No data"

/**
 * State while collecting all egos
 */
#define ID_REST_STATE_INIT 0

/**
 * Done collecting egos
 */
#define ID_REST_STATE_POST_INIT 1
/**
 * The configuration handle
 */
const struct GNUNET_CONFIGURATION_Handle *cfg;

/**
 * HTTP methods allows for this plugin
 */
static char *allow_methods;

/**
 * @brief struct returned by the initialization function of the plugin
 */
struct Plugin
{
  const struct GNUNET_CONFIGURATION_Handle *cfg;
};

/**
 * The default namestore ego
 */
struct EgoEntry
{
  /**
   * DLL
   */
  struct EgoEntry *next;

  /**
   * DLL
   */
  struct EgoEntry *prev;

  /**
   * Ego Identifier
   */
  char *identifier;

  /**
   * Public key string
   */
  char *keystring;

  /**
   * The Ego
   */
  struct GNUNET_IDENTITY_Ego *ego;
};

/**
 * The request handle
 */
struct RequestHandle
{
  /**
   * Records to store
   */
  char *record_name;

  /**
   * Records to store
   */
  struct GNUNET_GNSRECORD_Data *rd;

  /**
   * NAMESTORE Operation
   */
  struct GNUNET_NAMESTORE_QueueEntry *add_qe;

  /**
   * Response object
   */
  json_t *resp_object;

  /**
   * The processing state
   */
  int state;

  /**
   * Handle to NAMESTORE
   */
  struct GNUNET_NAMESTORE_Handle *ns_handle;

  /**
   * Handle to NAMESTORE it
   */
  struct GNUNET_NAMESTORE_ZoneIterator *list_it;

  /**
   * Private key for the zone
   */
  const struct GNUNET_CRYPTO_EcdsaPrivateKey *zone_pkey;

  /**
   * IDENTITY Operation
   */
  struct EgoEntry *ego_entry;

  /**
   * Ego list
   */
  struct EgoEntry *ego_head;

  /**
   * Ego list
   */
  struct EgoEntry *ego_tail;

  /**
   * IDENTITY Operation
   */
  struct GNUNET_IDENTITY_Operation *op;

  /**
   * Handle to Identity service.
   */
  struct GNUNET_IDENTITY_Handle *identity_handle;

  /**
   * Rest connection
   */
  struct GNUNET_REST_RequestHandle *rest_handle;

  /**
   * Desired timeout for the lookup (default is no timeout).
   */
  struct GNUNET_TIME_Relative timeout;

  /**
   * ID of a task associated with the resolution process.
   */
  struct GNUNET_SCHEDULER_Task *timeout_task;

  /**
   * The plugin result processor
   */
  GNUNET_REST_ResultProcessor proc;

  /**
   * The closure of the result processor
   */
  void *proc_cls;

  /**
   * The url
   */
  char *url;

  /**
   * Error response message
   */
  char *emsg;

  /**
   * Response code
   */
  int response_code;
};

/**
 * Cleanup lookup handle
 * @param handle Handle to clean up
 */
static void
cleanup_handle (void *cls)
{
  struct RequestHandle *handle = cls;
  struct EgoEntry *ego_entry;
  struct EgoEntry *ego_tmp;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Cleaning up\n");
  if (NULL != handle->timeout_task)
  {
    GNUNET_SCHEDULER_cancel (handle->timeout_task);
    handle->timeout_task = NULL;
  }
  if (NULL != handle->record_name)
    GNUNET_free (handle->record_name);
  if (NULL != handle->url)
    GNUNET_free (handle->url);
  if (NULL != handle->emsg)
    GNUNET_free (handle->emsg);
  if (NULL != handle->rd)
  {
    if (NULL != handle->rd->data)
      GNUNET_free ((void *) handle->rd->data);
    GNUNET_free (handle->rd);
  }
  if (NULL != handle->timeout_task)
    GNUNET_SCHEDULER_cancel (handle->timeout_task);
  if (NULL != handle->list_it)
    GNUNET_NAMESTORE_zone_iteration_stop (handle->list_it);
  if (NULL != handle->add_qe)
    GNUNET_NAMESTORE_cancel (handle->add_qe);
  if (NULL != handle->identity_handle)
    GNUNET_IDENTITY_disconnect (handle->identity_handle);
  if (NULL != handle->ns_handle)
  {
    GNUNET_NAMESTORE_disconnect (handle->ns_handle);
  }

  for (ego_entry = handle->ego_head; NULL != ego_entry;)
  {
    ego_tmp = ego_entry;
    ego_entry = ego_entry->next;
    GNUNET_free (ego_tmp->identifier);
    GNUNET_free (ego_tmp->keystring);
    GNUNET_free (ego_tmp);
  }

  if (NULL != handle->resp_object)
  {
    json_decref (handle->resp_object);
  }

  GNUNET_free (handle);
}


/**
 * Task run on errors.  Reports an error and cleans up everything.
 *
 * @param cls the `struct RequestHandle`
 */
static void
do_error (void *cls)
{
  struct RequestHandle *handle = cls;
  struct MHD_Response *resp;
  json_t *json_error = json_object ();
  char *response;

  if (NULL == handle->emsg)
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_ERROR_UNKNOWN);

  json_object_set_new (json_error, "error", json_string (handle->emsg));

  if (0 == handle->response_code)
    handle->response_code = MHD_HTTP_INTERNAL_SERVER_ERROR;
  response = json_dumps (json_error, 0);
  resp = GNUNET_REST_create_response (response);
  handle->proc (handle->proc_cls, resp, handle->response_code);
  json_decref (json_error);
  GNUNET_free (response);
  GNUNET_SCHEDULER_add_now (&cleanup_handle, handle);
}


/**
 * Get EgoEntry from list with either a public key or a name
 * If public key and name are not NULL, it returns the public key result first
 *
 * @param handle the RequestHandle
 * @param pubkey the public key of an identity (only one can be NULL)
 * @param name the name of an identity (only one can be NULL)
 * @return EgoEntry or NULL if not found
 */
struct EgoEntry *
get_egoentry_namestore (struct RequestHandle *handle, char *name)
{
  struct EgoEntry *ego_entry;
  if (NULL != name)
  {
    for (ego_entry = handle->ego_head; NULL != ego_entry;
         ego_entry = ego_entry->next)
    {
      if (0 != strcasecmp (name, ego_entry->identifier))
        continue;
      return ego_entry;
    }
  }
  return NULL;
}


/**
 * Does internal server error when iteration failed.
 *
 * @param cls the `struct RequestHandle`
 */
static void
namestore_iteration_error (void *cls)
{
  struct RequestHandle *handle = cls;
  handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_FAILED);
  GNUNET_SCHEDULER_add_now (&do_error, handle);
  return;
}


/**
 * Create finished callback
 *
 * @param cls the `struct RequestHandle`
 * @param success the success indicating integer, GNUNET_OK on success
 * @param emsg the error message (can be NULL)
 */
static void
create_finished (void *cls, int32_t success, const char *emsg)
{
  struct RequestHandle *handle = cls;
  struct MHD_Response *resp;

  handle->add_qe = NULL;
  if (GNUNET_YES != success)
  {
    if (NULL != emsg)
    {
      handle->emsg = GNUNET_strdup (emsg);
      GNUNET_SCHEDULER_add_now (&do_error, handle);
      return;
    }
    handle->emsg = GNUNET_strdup ("Error storing records");
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
  resp = GNUNET_REST_create_response (NULL);
  handle->proc (handle->proc_cls, resp, MHD_HTTP_NO_CONTENT);
  GNUNET_SCHEDULER_add_now (&cleanup_handle, handle);
}


/**
 * Delete finished callback
 *
 * @param cls the `struct RequestHandle`
 * @param success the success indicating integer, GNUNET_OK on success
 * @param emsg the error message (can be NULL)
 */
static void
del_finished (void *cls, int32_t success, const char *emsg)
{
  struct RequestHandle *handle = cls;

  handle->add_qe = NULL;
  if (GNUNET_NO == success)
  {
    handle->response_code = MHD_HTTP_NOT_FOUND;
    handle->emsg = GNUNET_strdup ("No record found");
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
  if (GNUNET_SYSERR == success)
  {
    if (NULL != emsg)
    {
      handle->emsg = GNUNET_strdup (emsg);
      GNUNET_SCHEDULER_add_now (&do_error, handle);
      return;
    }
    handle->emsg = GNUNET_strdup ("Deleting record failed");
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
  handle->proc (handle->proc_cls,
                GNUNET_REST_create_response (NULL),
                MHD_HTTP_NO_CONTENT);
  GNUNET_SCHEDULER_add_now (&cleanup_handle, handle);
}


/**
 * Iteration over all results finished, build final
 * response.
 *
 * @param cls the `struct RequestHandle`
 */
static void
namestore_list_finished (void *cls)
{
  struct RequestHandle *handle = cls;
  char *result_str;
  struct MHD_Response *resp;

  handle->list_it = NULL;

  if (NULL == handle->resp_object)
    handle->resp_object = json_array ();

  result_str = json_dumps (handle->resp_object, 0);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Result %s\n", result_str);
  resp = GNUNET_REST_create_response (result_str);
  handle->proc (handle->proc_cls, resp, MHD_HTTP_OK);
  GNUNET_free_non_null (result_str);
  GNUNET_SCHEDULER_add_now (&cleanup_handle, handle);
}


/**
 * Create a response with requested records
 *
 * @param handle the RequestHandle
 */
static void
namestore_list_iteration (void *cls,
                          const struct GNUNET_CRYPTO_EcdsaPrivateKey *zone_key,
                          const char *rname,
                          unsigned int rd_len,
                          const struct GNUNET_GNSRECORD_Data *rd)
{
  struct RequestHandle *handle = cls;
  json_t *record_obj;

  if (NULL == handle->resp_object)
    handle->resp_object = json_array ();

  for (unsigned int i = 0; i < rd_len; i++)
  {
    if ((GNUNET_GNSRECORD_TYPE_NICK == rd[i].record_type) &&
        (0 != strcmp (rname, GNUNET_GNS_EMPTY_LABEL_AT)))
      continue;

    record_obj = GNUNET_JSON_from_gns_record (rname, &rd[i]);

    if (NULL == record_obj)
      continue;

    json_array_append (handle->resp_object, record_obj);
    json_decref (record_obj);
  }

  GNUNET_NAMESTORE_zone_iterator_next (handle->list_it, 1);
}

/**
 * @param cls closure
 * @param ego ego handle
 * @param ctx context for application to store data for this ego
 *                 (during the lifetime of this process, initially NULL)
 * @param identifier identifier assigned by the user for this ego,
 *                   NULL if the user just deleted the ego and it
 *                   must thus no longer be used
 */
static void
default_ego_get (void *cls,
                 struct GNUNET_IDENTITY_Ego *ego,
                 void **ctx,
                 const char *identifier)
{
  struct RequestHandle *handle = cls;
  handle->op = NULL;

  if (ego == NULL)
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_NO_DEFAULT_ZONE);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
  handle->zone_pkey = GNUNET_IDENTITY_ego_get_private_key (ego);

  handle->list_it =
    GNUNET_NAMESTORE_zone_iteration_start (handle->ns_handle,
                                           handle->zone_pkey,
                                           &namestore_iteration_error,
                                           handle,
                                           &namestore_list_iteration,
                                           handle,
                                           &namestore_list_finished,
                                           handle);
  if (NULL == handle->list_it)
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_FAILED);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
}


/**
 * Handle namestore GET request
 *
 * @param con_handle the connection handle
 * @param url the url
 * @param cls the RequestHandle
 */
void
namestore_get (struct GNUNET_REST_RequestHandle *con_handle,
               const char *url,
               void *cls)
{
  struct RequestHandle *handle = cls;
  struct EgoEntry *ego_entry;
  char *egoname;

  egoname = NULL;
  ego_entry = NULL;

  // set zone to name if given
  if (strlen (GNUNET_REST_API_NS_NAMESTORE) < strlen (handle->url))
  {
    egoname = &handle->url[strlen (GNUNET_REST_API_NS_NAMESTORE) + 1];
    ego_entry = get_egoentry_namestore (handle, egoname);

    if (NULL == ego_entry)
    {
      handle->response_code = MHD_HTTP_NOT_FOUND;
      handle->emsg = GNUNET_strdup (GNUNET_REST_IDENTITY_NOT_FOUND);
      GNUNET_SCHEDULER_add_now (&do_error, handle);
      return;
    }
  }
  if (NULL != ego_entry)
  {
    handle->zone_pkey = GNUNET_IDENTITY_ego_get_private_key (ego_entry->ego);
  }

  if (NULL == handle->zone_pkey)
  {
    handle->op = GNUNET_IDENTITY_get (handle->identity_handle,
                                      "namestore",
                                      &default_ego_get,
                                      handle);
    return;
  }
  handle->list_it =
    GNUNET_NAMESTORE_zone_iteration_start (handle->ns_handle,
                                           handle->zone_pkey,
                                           &namestore_iteration_error,
                                           handle,
                                           &namestore_list_iteration,
                                           handle,
                                           &namestore_list_finished,
                                           handle);
  if (NULL == handle->list_it)
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_FAILED);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
}


/**
 * @param cls closure
 * @param ego ego handle
 * @param ctx context for application to store data for this ego
 *                 (during the lifetime of this process, initially NULL)
 * @param identifier identifier assigned by the user for this ego,
 *                   NULL if the user just deleted the ego and it
 *                   must thus no longer be used
 */
static void
default_ego_post (void *cls,
                  struct GNUNET_IDENTITY_Ego *ego,
                  void **ctx,
                  const char *identifier)
{
  struct RequestHandle *handle = cls;
  handle->op = NULL;

  if (ego == NULL)
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_NO_DEFAULT_ZONE);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
  handle->zone_pkey = GNUNET_IDENTITY_ego_get_private_key (ego);

  handle->add_qe = GNUNET_NAMESTORE_records_store (handle->ns_handle,
                                                   handle->zone_pkey,
                                                   handle->record_name,
                                                   1,
                                                   handle->rd,
                                                   &create_finished,
                                                   handle);
  if (NULL == handle->add_qe)
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_FAILED);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
}


static void
ns_lookup_error_cb (void *cls)
{
  struct RequestHandle *handle = cls;
  handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_FAILED);
  GNUNET_SCHEDULER_add_now (&do_error, handle);
}


static void
ns_lookup_cb (void *cls,
              const struct GNUNET_CRYPTO_EcdsaPrivateKey *zone,
              const char *label,
              unsigned int rd_count,
              const struct GNUNET_GNSRECORD_Data *rd)
{
  struct RequestHandle *handle = cls;
  struct GNUNET_GNSRECORD_Data rd_new[rd_count + 1];
  for (int i = 0; i < rd_count; i++)
    rd_new[i] = rd[i];
  rd_new[rd_count] = *handle->rd;
  handle->add_qe = GNUNET_NAMESTORE_records_store (handle->ns_handle,
                                                   handle->zone_pkey,
                                                   handle->record_name,
                                                   rd_count + 1,
                                                   rd_new,
                                                   &create_finished,
                                                   handle);
  if (NULL == handle->add_qe)
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_FAILED);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
}


/**
 * Handle namestore POST request
 *
 * @param con_handle the connection handle
 * @param url the url
 * @param cls the RequestHandle
 */
void
namestore_add (struct GNUNET_REST_RequestHandle *con_handle,
               const char *url,
               void *cls)
{
  struct RequestHandle *handle = cls;
  struct GNUNET_GNSRECORD_Data *gns_record;
  struct EgoEntry *ego_entry;
  char *egoname;
  json_t *data_js;
  json_t *name_json;
  json_error_t err;
  char term_data[handle->rest_handle->data_size + 1];

  struct GNUNET_JSON_Specification gnsspec[] =
    {GNUNET_JSON_spec_gnsrecord_data (&gns_record), GNUNET_JSON_spec_end ()};

  if (0 >= handle->rest_handle->data_size)
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_NO_DATA);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
  term_data[handle->rest_handle->data_size] = '\0';
  GNUNET_memcpy (term_data,
                 handle->rest_handle->data,
                 handle->rest_handle->data_size);
  data_js = json_loads (term_data, JSON_DECODE_ANY, &err);
  if (GNUNET_OK != GNUNET_JSON_parse (data_js, gnsspec, NULL, NULL))
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_INVALID_DATA);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    GNUNET_JSON_parse_free (gnsspec);
    json_decref (data_js);
    return;
  }
  handle->rd = gns_record;

  name_json = json_object_get (data_js, "record_name");
  if (! json_is_string (name_json))
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_INVALID_DATA);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    json_decref (data_js);
    return;
  }
  handle->record_name = GNUNET_strdup (json_string_value (name_json));
  if (NULL == handle->record_name)
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_INVALID_DATA);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    json_decref (data_js);
    return;
  }
  if (0 >= strlen (handle->record_name))
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_INVALID_DATA);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    json_decref (data_js);
    return;
  }
  json_decref (data_js);

  egoname = NULL;
  ego_entry = NULL;

  // set zone to name if given
  if (strlen (GNUNET_REST_API_NS_NAMESTORE) < strlen (handle->url))
  {
    egoname = &handle->url[strlen (GNUNET_REST_API_NS_NAMESTORE) + 1];
    ego_entry = get_egoentry_namestore (handle, egoname);

    if (NULL == ego_entry)
    {
      handle->response_code = MHD_HTTP_NOT_FOUND;
      handle->emsg = GNUNET_strdup (GNUNET_REST_IDENTITY_NOT_FOUND);
      GNUNET_SCHEDULER_add_now (&do_error, handle);
      return;
    }
  }
  if (NULL != ego_entry)
  {
    handle->zone_pkey = GNUNET_IDENTITY_ego_get_private_key (ego_entry->ego);
  }
  if (NULL == handle->zone_pkey)
  {
    handle->op = GNUNET_IDENTITY_get (handle->identity_handle,
                                      "namestore",
                                      &default_ego_post,
                                      handle);
    return;
  }
  handle->add_qe = GNUNET_NAMESTORE_records_lookup (handle->ns_handle,
                                                    handle->zone_pkey,
                                                    handle->record_name,
                                                    &ns_lookup_error_cb,
                                                    handle,
                                                    &ns_lookup_cb,
                                                    handle);
  if (NULL == handle->add_qe)
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_FAILED);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
}


/**
 * @param cls closure
 * @param ego ego handle
 * @param ctx context for application to store data for this ego
 *                 (during the lifetime of this process, initially NULL)
 * @param identifier identifier assigned by the user for this ego,
 *                   NULL if the user just deleted the ego and it
 *                   must thus no longer be used
 */
static void
default_ego_delete (void *cls,
                    struct GNUNET_IDENTITY_Ego *ego,
                    void **ctx,
                    const char *identifier)
{
  struct RequestHandle *handle = cls;
  handle->op = NULL;

  if (ego == NULL)
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_NO_DEFAULT_ZONE);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
  handle->zone_pkey = GNUNET_IDENTITY_ego_get_private_key (ego);

  handle->add_qe = GNUNET_NAMESTORE_records_store (handle->ns_handle,
                                                   handle->zone_pkey,
                                                   handle->record_name,
                                                   0,
                                                   NULL,
                                                   &del_finished,
                                                   handle);
  if (NULL == handle->add_qe)
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_FAILED);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
}


/**
 * Handle namestore DELETE request
 *
 * @param con_handle the connection handle
 * @param url the url
 * @param cls the RequestHandle
 */
void
namestore_delete (struct GNUNET_REST_RequestHandle *con_handle,
                  const char *url,
                  void *cls)
{
  struct RequestHandle *handle = cls;
  struct GNUNET_HashCode key;
  struct EgoEntry *ego_entry;
  char *egoname;

  egoname = NULL;
  ego_entry = NULL;

  // set zone to name if given
  if (strlen (GNUNET_REST_API_NS_NAMESTORE) < strlen (handle->url))
  {
    egoname = &handle->url[strlen (GNUNET_REST_API_NS_NAMESTORE) + 1];
    ego_entry = get_egoentry_namestore (handle, egoname);

    if (NULL == ego_entry)
    {
      handle->response_code = MHD_HTTP_NOT_FOUND;
      handle->emsg = GNUNET_strdup (GNUNET_REST_IDENTITY_NOT_FOUND);
      GNUNET_SCHEDULER_add_now (&do_error, handle);
      return;
    }
  }
  if (NULL != ego_entry)
  {
    handle->zone_pkey = GNUNET_IDENTITY_ego_get_private_key (ego_entry->ego);
  }

  GNUNET_CRYPTO_hash ("record_name", strlen ("record_name"), &key);
  if (GNUNET_NO ==
      GNUNET_CONTAINER_multihashmap_contains (con_handle->url_param_map, &key))
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_INVALID_DATA);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
  handle->record_name = GNUNET_strdup (
    GNUNET_CONTAINER_multihashmap_get (con_handle->url_param_map, &key));

  if (NULL == handle->zone_pkey)
  {
    handle->op = GNUNET_IDENTITY_get (handle->identity_handle,
                                      "namestore",
                                      &default_ego_delete,
                                      handle);
    return;
  }

  handle->add_qe = GNUNET_NAMESTORE_records_store (handle->ns_handle,
                                                   handle->zone_pkey,
                                                   handle->record_name,
                                                   0,
                                                   NULL,
                                                   &del_finished,
                                                   handle);
  if (NULL == handle->add_qe)
  {
    handle->emsg = GNUNET_strdup (GNUNET_REST_NAMESTORE_FAILED);
    GNUNET_SCHEDULER_add_now (&do_error, handle);
    return;
  }
}


/**
 * Respond to OPTIONS request
 *
 * @param con_handle the connection handle
 * @param url the url
 * @param cls the RequestHandle
 */
static void
options_cont (struct GNUNET_REST_RequestHandle *con_handle,
              const char *url,
              void *cls)
{
  struct MHD_Response *resp;
  struct RequestHandle *handle = cls;

  // independent of path return all options
  resp = GNUNET_REST_create_response (NULL);
  MHD_add_response_header (resp, "Access-Control-Allow-Methods", allow_methods);
  handle->proc (handle->proc_cls, resp, MHD_HTTP_OK);
  GNUNET_SCHEDULER_add_now (&cleanup_handle, handle);
  return;
}


/**
 * Handle rest request
 *
 * @param handle the request handle
 */
static void
init_cont (struct RequestHandle *handle)
{
  struct GNUNET_REST_RequestHandlerError err;
  static const struct GNUNET_REST_RequestHandler handlers[] =
    {{MHD_HTTP_METHOD_GET, GNUNET_REST_API_NS_NAMESTORE, &namestore_get},
     {MHD_HTTP_METHOD_POST, GNUNET_REST_API_NS_NAMESTORE, &namestore_add},
     {MHD_HTTP_METHOD_DELETE, GNUNET_REST_API_NS_NAMESTORE, &namestore_delete},
     {MHD_HTTP_METHOD_OPTIONS, GNUNET_REST_API_NS_NAMESTORE, &options_cont},
     GNUNET_REST_HANDLER_END};

  if (GNUNET_NO ==
      GNUNET_REST_handle_request (handle->rest_handle, handlers, &err, handle))
  {
    handle->response_code = err.error_code;
    GNUNET_SCHEDULER_add_now (&do_error, handle);
  }
}


/**
 * This function is initially called for all egos and then again
 * whenever a ego's identifier changes or if it is deleted.  At the
 * end of the initial pass over all egos, the function is once called
 * with 'NULL' for 'ego'. That does NOT mean that the callback won't
 * be invoked in the future or that there was an error.
 *
 * When used with 'GNUNET_IDENTITY_create' or 'GNUNET_IDENTITY_get',
 * this function is only called ONCE, and 'NULL' being passed in
 * 'ego' does indicate an error (i.e. name is taken or no default
 * value is known).  If 'ego' is non-NULL and if '*ctx'
 * is set in those callbacks, the value WILL be passed to a subsequent
 * call to the identity callback of 'GNUNET_IDENTITY_connect' (if
 * that one was not NULL).
 *
 * When an identity is renamed, this function is called with the
 * (known) ego but the NEW identifier.
 *
 * When an identity is deleted, this function is called with the
 * (known) ego and "NULL" for the 'identifier'.  In this case,
 * the 'ego' is henceforth invalid (and the 'ctx' should also be
 * cleaned up).
 *
 * @param cls closure
 * @param ego ego handle
 * @param ctx context for application to store data for this ego
 *                 (during the lifetime of this process, initially NULL)
 * @param name identifier assigned by the user for this ego,
 *                   NULL if the user just deleted the ego and it
 *                   must thus no longer be used
 */
static void
id_connect_cb (void *cls,
               struct GNUNET_IDENTITY_Ego *ego,
               void **ctx,
               const char *name)
{
  struct RequestHandle *handle = cls;
  struct EgoEntry *ego_entry;
  struct GNUNET_CRYPTO_EcdsaPublicKey pk;

  if ((NULL == ego) && (ID_REST_STATE_INIT == handle->state))
  {
    handle->state = ID_REST_STATE_POST_INIT;
    init_cont (handle);
    return;
  }
  if (ID_REST_STATE_INIT == handle->state)
  {
    ego_entry = GNUNET_new (struct EgoEntry);
    GNUNET_IDENTITY_ego_get_public_key (ego, &pk);
    ego_entry->keystring = GNUNET_CRYPTO_ecdsa_public_key_to_string (&pk);
    ego_entry->ego = ego;
    GNUNET_asprintf (&ego_entry->identifier, "%s", name);
    GNUNET_CONTAINER_DLL_insert_tail (handle->ego_head,
                                      handle->ego_tail,
                                      ego_entry);
  }
}


/**
 * Function processing the REST call
 *
 * @param method HTTP method
 * @param url URL of the HTTP request
 * @param data body of the HTTP request (optional)
 * @param data_size length of the body
 * @param proc callback function for the result
 * @param proc_cls closure for callback function
 * @return GNUNET_OK if request accepted
 */
static void
rest_process_request (struct GNUNET_REST_RequestHandle *rest_handle,
                      GNUNET_REST_ResultProcessor proc,
                      void *proc_cls)
{
  struct RequestHandle *handle = GNUNET_new (struct RequestHandle);

  handle->response_code = 0;
  handle->timeout = GNUNET_TIME_UNIT_FOREVER_REL;
  handle->proc_cls = proc_cls;
  handle->proc = proc;
  handle->rest_handle = rest_handle;
  handle->zone_pkey = NULL;

  handle->url = GNUNET_strdup (rest_handle->url);
  if (handle->url[strlen (handle->url) - 1] == '/')
    handle->url[strlen (handle->url) - 1] = '\0';
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Connecting...\n");

  handle->ns_handle = GNUNET_NAMESTORE_connect (cfg);
  handle->identity_handle =
    GNUNET_IDENTITY_connect (cfg, &id_connect_cb, handle);
  handle->timeout_task =
    GNUNET_SCHEDULER_add_delayed (handle->timeout, &do_error, handle);

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Connected\n");
}


/**
 * Entry point for the plugin.
 *
 * @param cls Config info
 * @return NULL on error, otherwise the plugin context
 */
void *
libgnunet_plugin_rest_namestore_init (void *cls)
{
  static struct Plugin plugin;
  struct GNUNET_REST_Plugin *api;

  cfg = cls;
  if (NULL != plugin.cfg)
    return NULL; /* can only initialize once! */
  memset (&plugin, 0, sizeof (struct Plugin));
  plugin.cfg = cfg;
  api = GNUNET_new (struct GNUNET_REST_Plugin);
  api->cls = &plugin;
  api->name = GNUNET_REST_API_NS_NAMESTORE;
  api->process_request = &rest_process_request;
  GNUNET_asprintf (&allow_methods,
                   "%s, %s, %s, %s, %s",
                   MHD_HTTP_METHOD_GET,
                   MHD_HTTP_METHOD_POST,
                   MHD_HTTP_METHOD_PUT,
                   MHD_HTTP_METHOD_DELETE,
                   MHD_HTTP_METHOD_OPTIONS);

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, _ ("Namestore REST API initialized\n"));
  return api;
}


/**
 * Exit point from the plugin.
 *
 * @param cls the plugin context (as returned by "init")
 * @return always NULL
 */
void *
libgnunet_plugin_rest_namestore_done (void *cls)
{
  struct GNUNET_REST_Plugin *api = cls;
  struct Plugin *plugin = api->cls;
  plugin->cfg = NULL;

  GNUNET_free_non_null (allow_methods);
  GNUNET_free (api);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Namestore REST plugin is finished\n");
  return NULL;
}

/* end of plugin_rest_namestore.c */

