/*
  This file is part of TALER
  Copyright (C) 2020 Taler Systems SA

  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_delete_reserve.c
 * @brief Implementation of the DELETE /reserves/$RESERVE_PUB request of the merchant's HTTP API
 * @author Jonathan Buchanan
 */
 #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>
 #include <taler/taler_signatures.h>


/**
 * Handle for a DELETE /reserves/$RESERVE_PUB operation.
 */
struct TALER_MERCHANT_ReserveDeleteHandle
{

  /**
   * The url for this request.
   */
  char *url;

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

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

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

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

};


/**
 * Function called when we're done processing the
 * HTTP DELETE /reserves/$RESERVE_PUB request.
 *
 * @param cls the `struct TALER_MERCHANT_InstanceDeleteHandle`
 * @param response_code HTTP response code, 0 on error
 * @param json response body, NULL if not in JSON
 */
static void
handle_delete_reserve_finished (void *cls,
                                long response_code,
                                const void *response)
{
  struct TALER_MERCHANT_ReserveDeleteHandle *rdh = cls;
  const json_t *json = response;
  struct TALER_MERCHANT_HttpResponse hr = {
    .http_status = (unsigned int) response_code,
    .reply = json
  };

  rdh->job = NULL;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Got /reserves/$ID response with status code %u\n",
              (unsigned int) response_code);
  switch (response_code)
  {
  case MHD_HTTP_NO_CONTENT:
    break;
  default:
    /* unexpected response code */
    hr.ec = TALER_JSON_get_error_code (json);
    hr.hint = TALER_JSON_get_error_hint (json);
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Unexpected response code %u/%d\n",
                (unsigned int) response_code,
                (int) hr.ec);
    break;
  }
  rdh->cb (rdh->cb_cls,
           &hr);
  TALER_MERCHANT_reserve_delete_cancel (rdh);
}


/**
 * Delete the private key of a reserve.
 *
 * @param ctx the context
 * @param backend_url HTTP base URL for the backend
 * @param instance_id which instance should be deleted
 * @param purge purge instead of just deleting
 * @param instances_cb function to call with the
 *        backend's return
 * @param instances_cb_cls closure for @a config_cb
 * @return the instances handle; NULL upon error
 */
static struct TALER_MERCHANT_ReserveDeleteHandle *
reserve_delete (struct GNUNET_CURL_Context *ctx,
                const char *backend_url,
                const struct TALER_ReservePublicKeyP *reserve_pub,
                bool purge,
                TALER_MERCHANT_ReserveDeleteCallback cb,
                void *cb_cls)
{
  struct TALER_MERCHANT_ReserveDeleteHandle *rdh;

  rdh = GNUNET_new (struct TALER_MERCHANT_ReserveDeleteHandle);
  rdh->ctx = ctx;
  rdh->cb = cb;
  rdh->cb_cls = cb_cls;
  {
    char res_str[sizeof (*reserve_pub) * 2];
    char arg_str[sizeof (res_str) + 32];
    char *end;

    end = GNUNET_STRINGS_data_to_string (reserve_pub,
                                         sizeof (*reserve_pub),
                                         res_str,
                                         sizeof (res_str));
    *end = '\0';
    GNUNET_snprintf (arg_str,
                     sizeof (arg_str),
                     "private/reserves/%s",
                     res_str);
    if (purge)
      rdh->url = TALER_url_join (backend_url,
                                 arg_str,
                                 "purge",
                                 "yes",
                                 NULL);
    else
      rdh->url = TALER_url_join (backend_url,
                                 arg_str,
                                 NULL);
  }
  if (NULL == rdh->url)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Could not construct request URL.\n");
    GNUNET_free (rdh);
    return NULL;
  }
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Requesting URL '%s'\n",
              rdh->url);
  {
    CURL *eh;

    eh = curl_easy_init ();
    GNUNET_assert (CURLE_OK ==
                   curl_easy_setopt (eh,
                                     CURLOPT_URL,
                                     rdh->url));
    GNUNET_assert (CURLE_OK ==
                   curl_easy_setopt (eh,
                                     CURLOPT_CUSTOMREQUEST,
                                     MHD_HTTP_METHOD_DELETE));
    rdh->job = GNUNET_CURL_job_add (ctx,
                                    eh,
                                    &handle_delete_reserve_finished,
                                    rdh);
  }
  return rdh;
}


/**
 * Issue a DELETE /reserve/$RESERVE_ID request to the backend.  Only
 * deletes the private key of the reserve, preserves tipping data.
 *
 * @param ctx execution context
 * @param backend_url base URL of the merchant backend
 * @param reserve_pub which reserve should be queried
 * @param cb function to call with the result
 * @param cb_cls closure for @a cb
 * @return handle for this operation, NULL upon errors
 */
struct TALER_MERCHANT_ReserveDeleteHandle *
TALER_MERCHANT_reserve_delete (
  struct GNUNET_CURL_Context *ctx,
  const char *backend_url,
  const struct TALER_ReservePublicKeyP *reserve_pub,
  TALER_MERCHANT_ReserveDeleteCallback cb,
  void *cb_cls)
{
  return reserve_delete (ctx,
                         backend_url,
                         reserve_pub,
                         false,
                         cb,
                         cb_cls);
}


/**
 * Issue a DELETE /reserve/$RESERVE_ID request to the backend.
 * Purges the reserve, deleting all associated data. DANGEROUS.
 *
 * @param ctx execution context
 * @param backend_url base URL of the merchant backend
 * @param reserve_pub which reserve should be queried
 * @param cb function to call with the result
 * @param cb_cls closure for @a cb
 * @return handle for this operation, NULL upon errors
 */
struct TALER_MERCHANT_ReserveDeleteHandle *
TALER_MERCHANT_reserve_purge (struct GNUNET_CURL_Context *ctx,
                              const char *backend_url,
                              const struct TALER_ReservePublicKeyP *reserve_pub,
                              TALER_MERCHANT_ReserveDeleteCallback cb,
                              void *cb_cls)
{
  return reserve_delete (ctx,
                         backend_url,
                         reserve_pub,
                         true,
                         cb,
                         cb_cls);
}


/**
 * Cancel a DELETE (or purge) /reserve/$RESERVE_ID request.
 *
 * @param rdh handle to the request to be canceled
 */
void
TALER_MERCHANT_reserve_delete_cancel (
  struct TALER_MERCHANT_ReserveDeleteHandle *rdh)
{
  if (NULL != rdh->job)
    GNUNET_CURL_job_cancel (rdh->job);
  GNUNET_free (rdh->url);
  GNUNET_free (rdh);
}