/*
  This file is part of TALER
  Copyright (C) 2014, 2015, 2016 GNUnet e.V. and INRIA

  TALER is free software; you can redistribute it and/or modify it under the
  terms of the GNU Lesser General Public License as published by the Free Software
  Foundation; either version 2.1, or (at your option) any later version.

  TALER 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 Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License along with
  TALER; see the file COPYING.LGPL.  If not, see
  <http://www.gnu.org/licenses/>
*/
/**
 * @file lib/merchant_api_map.c
 * @brief Implementation of the /map/{in,out} request of the merchant's HTTP API
 * @author Marcello Stanisci
 */
#include "platform.h"
#include <curl/curl.h>
#include <jansson.h>
#include <microhttpd.h> /* just for HTTP status codes */
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_curl_lib.h>
#include "taler_merchant_service.h"
#include <taler/taler_json_lib.h>

struct TALER_MERCHANT_MapInOperation
{
  /**
   * Full URI, includes "/map/in".
   */
  char *url;

  /**
   * Request's body
   */
  char *json_enc;

  /**
   * Handle for the request.
   */
  struct GNUNET_CURL_Job *job;

  /**
   * Function to call with the result.
   */
  TALER_MERCHANT_MapInOperationCallback cb;

  /**
   * Closure for @a cb.
   */
  void *cb_cls;

  /**
   * Reference to the execution context.
   */
  struct GNUNET_CURL_Context *ctx;

};

/**
 * Cancel a /map/in request.
 *
 * @param mio handle to the request to be canceled
 */
void
TALER_MERCHANT_map_in_cancel (struct TALER_MERCHANT_MapInOperation *mio)
{
  if (NULL != mio->job)
  {
    GNUNET_CURL_job_cancel (mio->job);
    mio->job = NULL;
  }
  GNUNET_free (mio->url);
  GNUNET_free (mio->json_enc);
  GNUNET_free (mio);
}

/**
 * Function called when we're done processing the
 * HTTP /map/in request.
 *
 * @param cls the `struct TALER_MERCHANT_FIXME`
 * @param response_code HTTP response code, 0 on error
 * @param json response body, should be NULL
 */
static void
handle_map_in_finished (void *cls,
                          long response_code,
                          const json_t *json)
{
  struct TALER_MERCHANT_MapInOperation *mio = cls;

  /**
   * As no data is supposed to be extracted from this
   * call, we just invoke the provided callback from here.
   */
  mio->cb (mio->cb_cls,
           response_code);

  /* Right to call this here? */
  TALER_MERCHANT_map_in_cancel (mio);
}

/**
 * Issue a /map/in request to the backend.
 *
 * @param ctx execution context
 * @param backend_uri base URL of the merchant backend
 * @param contract contract to store
 * @param h_contract hashcode of `contract`
 * @param map_in_cb callback which will work the response gotten from the backend
 * @param map_in_cb_cls closure to pass to @a history_cb
 * @return handle for this operation, NULL upon errors
 */
struct TALER_MERCHANT_MapInOperation *
TALER_MERCHANT_map_in (struct GNUNET_CURL_Context *ctx,
                       const char *backend_uri,
                       const json_t *contract,
                       const struct GNUNET_HashCode *h_contract,
                       TALER_MERCHANT_MapInOperationCallback map_in_cb,
                       void *map_in_cb_cls)
{
  struct TALER_MERCHANT_MapInOperation *mio;
  CURL *eh;
  json_t *req;
  
  mio = GNUNET_new (struct TALER_MERCHANT_MapInOperation);
  mio->ctx = ctx;
  mio->cb = map_in_cb;
  mio->cb_cls = map_in_cb_cls;

  GNUNET_asprintf (&mio->url,
                   "%s%s",
                   backend_uri,
                   "/map/in");

  // build final json
  req = json_pack ("{s:o, s:o}",
                   "contract", contract,
                   "h_contract", GNUNET_JSON_from_data_auto (h_contract));

  GNUNET_assert (NULL !=
                  (mio->json_enc = json_dumps (req, JSON_COMPACT))
                );

  json_decref (req);
  eh = curl_easy_init ();

  GNUNET_assert (CURLE_OK ==
                 curl_easy_setopt (eh,
                                   CURLOPT_URL,
                                   mio->url));
  GNUNET_assert (CURLE_OK ==
                 curl_easy_setopt (eh,
                                   CURLOPT_POSTFIELDS,
                                   mio->json_enc));
  GNUNET_assert (CURLE_OK ==
                 curl_easy_setopt (eh,
                                   CURLOPT_POSTFIELDSIZE,
                                   strlen (mio->json_enc)));
  mio->job = GNUNET_CURL_job_add (ctx,
                                  eh,
                                  GNUNET_YES,
                                  &handle_map_in_finished,
                                  mio);
  return mio;
}