/*
  This file is part of TALER
  (C) 2014-2020 Taler Systems SA

  TALER 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, 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 General Public License for more details.

  You should have received a copy of the GNU General Public License along with
  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
*/
/**
 * @file backend/taler-merchant-httpd_get-tips-ID.c
 * @brief implementation of GET /tips/$ID
 * @author Marcello Stanisci
 * @author Christian Grothoff
 */
#include "platform.h"
#include <jansson.h>
#include <taler/taler_signatures.h>
#include <taler/taler_json_lib.h>
#include "taler-merchant-httpd_get-tips-ID.h"


/**
 * Handle a GET "/tips/$ID" request.
 *
 * @param rh context of the handler
 * @param connection the MHD connection to handle
 * @param[in,out] hc context with further information about the request
 * @return MHD result code
 */
MHD_RESULT
TMH_get_tips_ID (const struct TMH_RequestHandler *rh,
                 struct MHD_Connection *connection,
                 struct TMH_HandlerContext *hc)
{
  struct GNUNET_HashCode tip_id;
  enum GNUNET_DB_QueryStatus qs;
  struct TALER_Amount total_authorized;
  struct TALER_Amount total_picked_up;
  struct GNUNET_TIME_Absolute expiration;
  char *exchange_url;
  struct TALER_ReservePrivateKeyP reserve_priv;

  if (GNUNET_OK !=
      GNUNET_CRYPTO_hash_from_string (hc->infix,
                                      &tip_id))
  {
    /* tip_id has wrong encoding */
    GNUNET_break_op (0);
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_BAD_REQUEST,
                                       TALER_EC_PARAMETER_MALFORMED,
                                       "tip_id malformed");
  }

  TMH_db->preflight (TMH_db->cls);
  qs = TMH_db->lookup_tip (TMH_db->cls,
                           hc->instance->settings.id,
                           &tip_id,
                           &total_authorized,
                           &total_picked_up,
                           &expiration,
                           &exchange_url,
                           &reserve_priv);
  if (0 > qs)
  {
    /* single, read-only SQL statements should never cause
       serialization problems */
    GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR != qs);
    /* Always report on hard error as well to enable diagnostics */
    GNUNET_break (GNUNET_DB_STATUS_HARD_ERROR == qs);
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
                                       TALER_EC_GET_TIPS_DB_LOOKUP_ERROR,
                                       "database error looking up contract");
  }
  if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "Unknown tip id given: `%s'\n",
                hc->infix);
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_NOT_FOUND,
                                       TALER_EC_GET_TIPS_ID_UNKNOWN,
                                       "tip_id not found in database");
  }

  /* Build response */
  {
    MHD_RESULT ret;
    struct TALER_Amount remaining;
    struct GNUNET_TIME_Absolute expiration_round = expiration;

    GNUNET_break (0 <=
                  TALER_amount_subtract (&remaining,
                                         &total_authorized,
                                         &total_picked_up));

    GNUNET_TIME_round_abs (&expiration_round);

    ret = TALER_MHD_reply_json_pack (connection,
                                     MHD_HTTP_OK,
                                     "{s:s, s:o, s:o}",
                                     "exchange_url",
                                     exchange_url,
                                     "tip_amount",
                                     TALER_JSON_from_amount (&remaining),
                                     "expiration",
                                     GNUNET_JSON_from_time_abs (
                                       expiration_round));
    GNUNET_free (exchange_url);
    return ret;
  }
}


/* end of taler-merchant-httpd_get-tips-ID.c */