/*
  This file is part of TALER
  (C) 2014-2023 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 taler-merchant-httpd_get-rewards-ID.c
 * @brief implementation of GET /rewards/$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/taler_templating_lib.h>
#include "taler-merchant-httpd_get-rewards-ID.h"
#include "taler-merchant-httpd_helper.h"
#include "taler-merchant-httpd_mhd.h"
#include "taler-merchant-httpd_qr.h"


char *
TMH_make_taler_reward_uri (struct MHD_Connection *con,
                           const struct TALER_RewardIdentifierP *reward_id,
                           const char *instance_id)
{
  struct GNUNET_Buffer buf = { 0 };

  GNUNET_assert (NULL != instance_id);
  GNUNET_assert (NULL != reward_id);
  if (GNUNET_OK !=
      TMH_taler_uri_by_connection (con,
                                   "reward",
                                   instance_id,
                                   &buf))
  {
    GNUNET_break (0);
    return NULL;
  }
  /* Ensure previous part is slash-terminated */
  GNUNET_buffer_write_path (&buf,
                            "");
  GNUNET_buffer_write_data_encoded (&buf,
                                    reward_id,
                                    sizeof (*reward_id));
  return GNUNET_buffer_reap_str (&buf);
}


char *
TMH_make_reward_status_url (struct MHD_Connection *con,
                            const struct TALER_RewardIdentifierP *reward_id,
                            const char *instance_id)
{
  struct GNUNET_Buffer buf;

  GNUNET_assert (NULL != instance_id);
  GNUNET_assert (NULL != reward_id);
  if (GNUNET_OK !=
      TMH_base_url_by_connection (con,
                                  instance_id,
                                  &buf))
  {
    GNUNET_break (0);
    return NULL;
  }
  GNUNET_buffer_write_path (&buf,
                            "rewards/");
  GNUNET_buffer_write_data_encoded (&buf,
                                    reward_id,
                                    sizeof (*reward_id));
  return GNUNET_buffer_reap_str (&buf);
}


MHD_RESULT
TMH_get_rewards_ID (const struct TMH_RequestHandler *rh,
                    struct MHD_Connection *connection,
                    struct TMH_HandlerContext *hc)
{
  struct TALER_RewardIdentifierP reward_id;
  enum GNUNET_DB_QueryStatus qs;
  struct TALER_Amount total_authorized;
  struct TALER_Amount total_picked_up;
  struct GNUNET_TIME_Timestamp expiration;
  char *exchange_url;
  char *next_url;
  struct TALER_ReservePrivateKeyP reserve_priv;

  (void) rh;
  if (GNUNET_OK !=
      GNUNET_CRYPTO_hash_from_string (hc->infix,
                                      &reward_id.hash))
  {
    /* reward_id has wrong encoding */
    GNUNET_break_op (0);
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_BAD_REQUEST,
                                       TALER_EC_GENERIC_PARAMETER_MALFORMED,
                                       hc->infix);
  }

  TMH_db->preflight (TMH_db->cls);
  qs = TMH_db->lookup_reward (TMH_db->cls,
                              hc->instance->settings.id,
                              &reward_id,
                              &total_authorized,
                              &total_picked_up,
                              &expiration,
                              &exchange_url,
                              &next_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_GENERIC_DB_FETCH_FAILED,
                                       NULL);
  }
  if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "Unknown reward id given: `%s'\n",
                hc->infix);
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_NOT_FOUND,
                                       TALER_EC_MERCHANT_GENERIC_REWARD_ID_UNKNOWN,
                                       hc->infix);
  }

  /* Build response */
  {
    struct TALER_Amount remaining;
    MHD_RESULT ret;

    GNUNET_break (0 <=
                  TALER_amount_subtract (&remaining,
                                         &total_authorized,
                                         &total_picked_up));
    if (TMH_MHD_test_html_desired (connection))
    {
      char *qr;
      char *uri;
      char *reward_status_url;

      uri = TMH_make_taler_reward_uri (connection,
                                       &reward_id,
                                       hc->instance->settings.id);
      reward_status_url = TMH_make_reward_status_url (connection,
                                                      &reward_id,
                                                      hc->instance->settings.id);
      qr = TMH_create_qrcode (uri);
      if (NULL == qr)
      {
        GNUNET_break (0);
        GNUNET_free (uri);
        ret = TALER_MHD_reply_with_error (connection,
                                          MHD_HTTP_INTERNAL_SERVER_ERROR,
                                          TALER_EC_GENERIC_ALLOCATION_FAILURE,
                                          "during QR code generation");
      }
      else
      {
        json_t *context;

        context = GNUNET_JSON_PACK (
          TALER_JSON_pack_amount ("remaining_reward",
                                  &remaining),
          GNUNET_JSON_pack_string ("taler_reward_uri",
                                   uri),
          GNUNET_JSON_pack_string ("next_url",
                                   next_url),
          GNUNET_JSON_pack_string ("taler_reward_qrcode_svg",
                                   qr));
        ret = TALER_TEMPLATING_reply (connection,
                                      ( (0 == remaining.value) &&
                                        (0 == remaining.fraction) )
                                        ? MHD_HTTP_GONE
                                        : MHD_HTTP_OK,
                                      ( (0 == remaining.value) &&
                                        (0 == remaining.fraction) )
                                        ? "depleted_reward"
                                        : "offer_reward",
                                      hc->instance->settings.id,
                                      uri,
                                      context);
        json_decref (context);
      }
      GNUNET_free (reward_status_url);
      GNUNET_free (uri);
      GNUNET_free (qr);
    }
    else
    {
      ret = TALER_MHD_REPLY_JSON_PACK (
        connection,
        TALER_amount_is_zero (&remaining)
        ? MHD_HTTP_GONE
        : MHD_HTTP_OK,
        GNUNET_JSON_pack_string ("exchange_url",
                                 exchange_url),
        GNUNET_JSON_pack_string ("next_url",
                                 next_url),
        TALER_JSON_pack_amount ("reward_amount",
                                &remaining),
        GNUNET_JSON_pack_timestamp ("expiration",
                                    expiration));
    }
    GNUNET_free (exchange_url);
    GNUNET_free (next_url);
    return ret;
  }
}


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