/*
   This file is part of TALER
   Copyright (C) 2023 Taler Systems SA

   TALER is free software; you can redistribute it and/or modify it under the
   terms of the GNU 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 backenddb/pg_lookup_reward_details.c
 * @brief Implementation of the lookup_reward_details function for Postgres
 * @author Iván Ávalos
 */
#include "platform.h"
#include <taler/taler_error_codes.h>
#include <taler/taler_dbevents.h>
#include <taler/taler_pq_lib.h>
#include "pg_lookup_reward_details.h"
#include "pg_helper.h"

/**
 * Closure for #lookup_pickup_details_cb().
 */
struct LookupRewardDetailsContext
{
  /**
   * Length of the @e sigs array
   */
  unsigned int *pickups_length;

  /**
   * Where to store the signatures.
   */
  struct TALER_MERCHANTDB_PickupDetails **pickups;

  /**
   * Database handle.
   */
  struct PostgresClosure *pg;

  /**
   * Transaction status.
   */
  enum GNUNET_DB_QueryStatus qs;

};


/**
 * Function to be called with the results of a SELECT statement
 * that has returned @a num_results results about pickups.
 *
 * @param[in,out] cls of type `struct LookupRewardDetailsContext *`
 * @param result the postgres result
 * @param num_results the number of results in @a result
 */
static void
lookup_pickup_details_cb (void *cls,
                          PGresult *result,
                          unsigned int num_results)
{
  struct LookupRewardDetailsContext *ltdc = cls;

  *ltdc->pickups_length = num_results;
  *ltdc->pickups = GNUNET_new_array (num_results,
                                     struct TALER_MERCHANTDB_PickupDetails);
  for (unsigned int i = 0; i < num_results; i++)
  {
    struct TALER_MERCHANTDB_PickupDetails *pd = &((*ltdc->pickups)[i]);
    uint64_t num_planchets = 0;
    struct GNUNET_PQ_ResultSpec rs[] = {
      GNUNET_PQ_result_spec_auto_from_type ("pickup_id",
                                            &pd->pickup_id),
      TALER_PQ_result_spec_amount_with_currency ("amount",
                                                 &pd->requested_amount),
      GNUNET_PQ_result_spec_uint64 ("num_planchets",
                                    &num_planchets),
      GNUNET_PQ_result_spec_end
    };

    if (GNUNET_OK !=
        GNUNET_PQ_extract_result (result,
                                  rs,
                                  i))
    {
      GNUNET_break (0);
      ltdc->qs = GNUNET_DB_STATUS_HARD_ERROR;
      GNUNET_array_grow (*ltdc->pickups,
                         *ltdc->pickups_length,
                         0);
      return;
    }

    pd->num_planchets = num_planchets;
  }
}


enum GNUNET_DB_QueryStatus
TMH_PG_lookup_reward_details (void *cls,
                              const char *instance_id,
                              const struct TALER_RewardIdentifierP *reward_id,
                              bool fpu,
                              struct TALER_Amount *total_authorized,
                              struct TALER_Amount *total_picked_up,
                              char **justification,
                              struct GNUNET_TIME_Timestamp *expiration,
                              struct TALER_ReservePublicKeyP *reserve_pub,
                              unsigned int *pickups_length,
                              struct TALER_MERCHANTDB_PickupDetails **pickups)
{
  struct PostgresClosure *pg = cls;
  uint64_t reward_serial;
  enum GNUNET_DB_QueryStatus qs;
  {
    struct GNUNET_PQ_QueryParam params[] = {
      GNUNET_PQ_query_param_string (instance_id),
      GNUNET_PQ_query_param_auto_from_type (reward_id),
      GNUNET_PQ_query_param_end
    };
    struct GNUNET_PQ_ResultSpec rs[] = {
      GNUNET_PQ_result_spec_uint64 ("reward_serial",
                                    &reward_serial),
      TALER_PQ_result_spec_amount_with_currency ("amount",
                                                 total_authorized),
      TALER_PQ_result_spec_amount_with_currency ("picked_up",
                                                 total_picked_up),
      GNUNET_PQ_result_spec_string ("justification",
                                    justification),
      GNUNET_PQ_result_spec_timestamp ("expiration",
                                       expiration),
      GNUNET_PQ_result_spec_auto_from_type ("reserve_pub",
                                            reserve_pub),
      GNUNET_PQ_result_spec_end
    };

    check_connection (pg);
    PREPARE (pg,
             "lookup_reward_details",
             "SELECT"
             " reward_serial"
             ",amount"
             ",picked_up"
             ",justification"
             ",merchant_rewards.expiration"
             ",reserve_pub"
             " FROM merchant_rewards"
             " JOIN merchant_reward_reserves USING (reserve_serial)"
             " WHERE reward_id = $2"
             "   AND merchant_serial ="
             "     (SELECT merchant_serial"
             "        FROM merchant_instances"
             "       WHERE merchant_id=$1)");

    qs = GNUNET_PQ_eval_prepared_singleton_select (pg->conn,
                                                   "lookup_reward_details",
                                                   params,
                                                   rs);
    if (qs <= 0)
      return qs;
    if (! fpu)
    {
      *pickups_length = 0;
      *pickups = NULL;
      return qs;
    }
  }
  {
    struct GNUNET_PQ_QueryParam params[] = {
      GNUNET_PQ_query_param_uint64 (&reward_serial),
      GNUNET_PQ_query_param_end
    };

    struct LookupRewardDetailsContext ltdc = {
      .pickups_length = pickups_length,
      .pickups = pickups,
      .pg = pg,
      .qs = GNUNET_DB_STATUS_SUCCESS_ONE_RESULT
    };

    PREPARE (pg,
             "lookup_pickup_details",
             "SELECT"
             " pickup_id"
             ",amount"
             ",COUNT(blind_sig) AS num_planchets"
             " FROM merchant_reward_pickups"
             " JOIN merchant_reward_pickup_signatures USING (pickup_serial)"
             " WHERE reward_serial = $1"
             " GROUP BY pickup_serial");

    qs = GNUNET_PQ_eval_prepared_multi_select (pg->conn,
                                               "lookup_pickup_details",
                                               params,
                                               &lookup_pickup_details_cb,
                                               &ltdc);
    if (qs < 0)
      return qs;
    return ltdc.qs;
  }
}