/*
  This file is part of TALER
  Copyright (C) 2014-2017, 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_get_reserves.c
 * @brief Implementation of the GET /reserves request of the merchant's HTTP API
 * @author Marcello Stanisci
 * @author Christian Grothoff
 */
#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>


/**
 * @brief A Handle for tracking wire reserves.
 */
struct TALER_MERCHANT_ReservesGetHandle
{

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

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

  /**
   * Function to call with the result.
   */
  TALER_MERCHANT_ReservesGetCallback 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 GET /reserves request.
 *
 * @param cls the `struct TALER_MERCHANT_ReservesGetHandle`
 * @param response_code HTTP response code, 0 on error
 * @param json response body, NULL if not in JSON
 */
static void
handle_reserves_get_finished (void *cls,
                              long response_code,
                              const void *response)
{
  struct TALER_MERCHANT_ReservesGetHandle *rgh = cls;
  const json_t *json = response;
  struct TALER_MERCHANT_HttpResponse hr = {
    .http_status = (unsigned int) response_code,
    .reply = json
  };

  rgh->job = NULL;
  switch (response_code)
  {
  case 0:
    hr.ec = TALER_EC_INVALID_RESPONSE;
    break;
  case MHD_HTTP_OK:
    {
      json_t *reserves;
      struct GNUNET_JSON_Specification spec[] = {
        GNUNET_JSON_spec_json ("reserves",
                               &reserves),
        GNUNET_JSON_spec_end ()
      };

      if (GNUNET_OK !=
          GNUNET_JSON_parse (json,
                             spec,
                             NULL, NULL))
      {
        GNUNET_break_op (0);
        hr.http_status = 0;
        hr.ec = TALER_EC_INVALID_RESPONSE;
        break;
      }
      else
      {
        size_t rds_length;
        struct TALER_MERCHANT_ReserveSummary *rds;
        json_t *reserve;
        unsigned int i;
        bool ok;

        if (! json_is_array (reserves))
        {
          GNUNET_break_op (0);
          GNUNET_JSON_parse_free (spec);
          hr.http_status = 0;
          hr.ec = TALER_EC_INVALID_RESPONSE;
          break;
        }
        rds_length = json_array_size (reserves);
        rds = GNUNET_new_array (rds_length,
                                struct TALER_MERCHANT_ReserveSummary);
        ok = true;
        json_array_foreach (reserves, i, reserve) {
          struct TALER_MERCHANT_ReserveSummary *rd = &rds[i];
          struct GNUNET_JSON_Specification ispec[] = {
            GNUNET_JSON_spec_fixed_auto ("reserve_pub",
                                         &rd->reserve_pub),
            TALER_JSON_spec_absolute_time ("creation_time",
                                           &rd->creation_time),
            TALER_JSON_spec_absolute_time ("expiration_time",
                                           &rd->expiration_time),
            TALER_JSON_spec_amount ("merchant_initial_amount",
                                    &rd->merchant_initial_amount),
            TALER_JSON_spec_amount ("exchange_initial_amount",
                                    &rd->exchange_initial_amount),
            TALER_JSON_spec_amount ("pickup_amount",
                                    &rd->pickup_amount),
            TALER_JSON_spec_amount ("committed_amount",
                                    &rd->committed_amount),
            GNUNET_JSON_spec_bool ("active",
                                   &rd->active),
            GNUNET_JSON_spec_end ()
          };

          if (GNUNET_OK !=
              GNUNET_JSON_parse (reserve,
                                 ispec,
                                 NULL, NULL))
          {
            GNUNET_break_op (0);
            ok = false;
            break;
          }
        }

        if (! ok)
        {
          GNUNET_break_op (0);
          GNUNET_free (rds);
          GNUNET_JSON_parse_free (spec);
          hr.http_status = 0;
          hr.ec = TALER_EC_INVALID_RESPONSE;
          break;
        }
        rgh->cb (rgh->cb_cls,
                 &hr,
                 rds_length,
                 rds);
        GNUNET_free (rds);
        GNUNET_JSON_parse_free (spec);
        TALER_MERCHANT_reserves_get_cancel (rgh);
        return;
      }
    }
  case MHD_HTTP_INTERNAL_SERVER_ERROR:
    /* Server had an internal issue; we should retry, but this API
       leaves this to the application */
    hr.ec = TALER_JSON_get_error_code (json);
    hr.hint = TALER_JSON_get_error_hint (json);
    break;
  default:
    /* unexpected response code */
    GNUNET_break_op (0);
    TALER_MERCHANT_parse_error_details_ (json,
                                         response_code,
                                         &hr);
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Unexpected response code %u/%d\n",
                (unsigned int) response_code,
                (int) hr.ec);
    response_code = 0;
    break;
  }
  rgh->cb (rgh->cb_cls,
           &hr,
           0,
           NULL);
  TALER_MERCHANT_reserves_get_cancel (rgh);
}


/**
 * Issue a GET /reserves request to the backend.  Informs the backend
 * that a customer wants to pick up a reserves.
 *
 * @param ctx execution context
 * @param backend_url base URL of the merchant backend
 * @param after filter for reserves created after this date, use 0 for no filtering
 * @param active filter for reserves that are active
 * @param failures filter for reserves where we disagree about the balance with
 *        the exchange
 * @param cb function to call with the result(s)
 * @param cb_cls closure for @a cb
 * @return handle for this operation, NULL upon errors
 */
struct TALER_MERCHANT_ReservesGetHandle *
TALER_MERCHANT_reserves_get (struct GNUNET_CURL_Context *ctx,
                             const char *backend_url,
                             struct GNUNET_TIME_Absolute after,
                             enum TALER_EXCHANGE_YesNoAll active,
                             enum TALER_EXCHANGE_YesNoAll failures,
                             TALER_MERCHANT_ReservesGetCallback cb,
                             void *cb_cls)
{
  struct TALER_MERCHANT_ReservesGetHandle *rgh;
  CURL *eh;
  const char *active_s = NULL;
  const char *failures_s = NULL;
  char *after_s;

  rgh = GNUNET_new (struct TALER_MERCHANT_ReservesGetHandle);
  rgh->ctx = ctx;
  rgh->cb = cb;
  rgh->cb_cls = cb_cls;
  active_s = TALER_yna_to_string (active);
  failures_s = TALER_yna_to_string (failures);
  after_s = GNUNET_strdup (GNUNET_STRINGS_absolute_time_to_string (
                             after));
  rgh->url = TALER_url_join (backend_url,
                             "private/reserves",
                             "active",
                             active_s,
                             "failures",
                             failures_s,
                             "after",
                             after.abs_value_us != 0
                             ? after_s
                             : NULL,
                             NULL);
  GNUNET_free (after_s);
  if (NULL == rgh->url)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Could not construct request URL.\n");
    GNUNET_free (rgh);
    return NULL;
  }
  eh = curl_easy_init ();
  GNUNET_assert (CURLE_OK ==
                 curl_easy_setopt (eh,
                                   CURLOPT_URL,
                                   rgh->url));
  rgh->job = GNUNET_CURL_job_add (ctx,
                                  eh,
                                  &handle_reserves_get_finished,
                                  rgh);
  return rgh;
}


/**
 * Cancel a GET /reserves request.
 *
 * @param rgh handle to the request to be canceled
 */
void
TALER_MERCHANT_reserves_get_cancel (
  struct TALER_MERCHANT_ReservesGetHandle *rgh)
{
  if (NULL != rgh->job)
  {
    GNUNET_CURL_job_cancel (rgh->job);
    rgh->job = NULL;
  }
  GNUNET_free (rgh->url);
  GNUNET_free (rgh);
}


/* end of merchant_api_get_reserves.c */