/*
   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_reserve.c
 * @brief Implementation of the lookup_reserve 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_reserve.h"
#include "pg_helper.h"

/**
 * Closure for #lookup_reserve_rewards_cb().
 */
struct LookupRewardsContext
{
  /**
   * Postgres context.
   */
  struct PostgresClosure *pg;

  /**
   * Array with information about rewards generated from this reserve.
   */
  struct TALER_MERCHANTDB_RewardDetails *rewards;

  /**
   * Length of the @e rewards array.
   */
  unsigned int rewards_length;

  /**
   * Set in case of errors.
   */
  enum GNUNET_DB_QueryStatus qs;
};


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

  GNUNET_array_grow (ltc->rewards,
                     ltc->rewards_length,
                     num_results);
  for (unsigned int i = 0; i < num_results; i++)
  {
    struct TALER_MERCHANTDB_RewardDetails *td = &ltc->rewards[i];
    struct GNUNET_PQ_ResultSpec rs[] = {
      GNUNET_PQ_result_spec_string ("justification",
                                    &td->reason),
      GNUNET_PQ_result_spec_auto_from_type ("reward_id",
                                            &td->reward_id),
      TALER_PQ_result_spec_amount_with_currency ("amount",
                                                 &td->total_amount),
      GNUNET_PQ_result_spec_end
    };

    if (GNUNET_OK !=
        GNUNET_PQ_extract_result (result,
                                  rs,
                                  i))
    {
      GNUNET_break (0);
      ltc->qs = GNUNET_DB_STATUS_HARD_ERROR;
      return;
    }
  }
}


enum GNUNET_DB_QueryStatus
TMH_PG_lookup_reserve (void *cls,
                       const char *instance_id,
                       const struct TALER_ReservePublicKeyP *reserve_pub,
                       bool fetch_rewards,
                       TALER_MERCHANTDB_ReserveDetailsCallback cb,
                       void *cb_cls)
{
  struct PostgresClosure *pg = cls;
  struct LookupRewardsContext ltc = {
    .pg = pg,
    .qs = GNUNET_DB_STATUS_SUCCESS_ONE_RESULT
  };
  struct GNUNET_PQ_QueryParam params[] = {
    GNUNET_PQ_query_param_string (instance_id),
    GNUNET_PQ_query_param_auto_from_type (reserve_pub),
    GNUNET_PQ_query_param_end
  };
  struct GNUNET_TIME_Timestamp creation_time;
  struct GNUNET_TIME_Timestamp expiration_time;
  struct TALER_Amount merchant_initial_balance;
  struct TALER_Amount exchange_initial_balance;
  struct TALER_Amount pickup_amount;
  struct TALER_Amount committed_amount;
  struct TALER_MasterPublicKeyP master_pub;
  bool active;
  char *exchange_url = NULL;
  struct GNUNET_PQ_ResultSpec rs[] = {
    GNUNET_PQ_result_spec_timestamp ("creation_time",
                                     &creation_time),
    GNUNET_PQ_result_spec_timestamp ("expiration",
                                     &expiration_time),
    TALER_PQ_result_spec_amount_with_currency ("merchant_initial_balance",
                                               &merchant_initial_balance),
    TALER_PQ_result_spec_amount_with_currency ("exchange_initial_balance",
                                               &exchange_initial_balance),
    TALER_PQ_result_spec_amount_with_currency ("rewards_picked_up",
                                               &pickup_amount),
    TALER_PQ_result_spec_amount_with_currency ("rewards_committed",
                                               &committed_amount),
    GNUNET_PQ_result_spec_auto_from_type ("master_pub",
                                          &master_pub),
    GNUNET_PQ_result_spec_bool ("active",
                                &active),
    GNUNET_PQ_result_spec_allow_null (
      GNUNET_PQ_result_spec_string ("exchange_url",
                                    &exchange_url),
      NULL),
    GNUNET_PQ_result_spec_end
  };
  enum GNUNET_DB_QueryStatus qs;

  check_connection (pg);
  PREPARE (pg,
           "lookup_reserve",
           "SELECT"
           " creation_time"
           ",expiration"
           ",merchant_initial_balance"
           ",exchange_initial_balance"
           ",rewards_committed"
           ",rewards_picked_up"
           ",reserve_priv IS NOT NULL AS active"
           ",exchange_url"
           ",master_pub"
           " FROM merchant_reward_reserves"
           " FULL OUTER JOIN merchant_reward_reserve_keys USING (reserve_serial)"
           " WHERE reserve_pub = $2"
           "   AND merchant_serial ="
           "     (SELECT merchant_serial"
           "        FROM merchant_instances"
           "       WHERE merchant_id=$1)");

  qs = GNUNET_PQ_eval_prepared_singleton_select (pg->conn,
                                                 "lookup_reserve",
                                                 params,
                                                 rs);
  if (qs < 0)
    return qs;
  if (! fetch_rewards)
  {
    cb (cb_cls,
        creation_time,
        expiration_time,
        &merchant_initial_balance,
        &exchange_initial_balance,
        &pickup_amount,
        &committed_amount,
        active,
        &master_pub,
        exchange_url,
        0,
        NULL);
    GNUNET_PQ_cleanup_result (rs);
    return qs;
  }

  PREPARE (pg,
           "lookup_reserve_rewards",
           "SELECT"
           " justification"
           ",reward_id"
           ",amount"
           " FROM merchant_rewards"
           " WHERE reserve_serial ="
           "  (SELECT reserve_serial"
           "     FROM merchant_reward_reserves"
           "      WHERE reserve_pub=$2"
           "        AND merchant_serial ="
           "       (SELECT merchant_serial"
           "          FROM merchant_instances"
           "         WHERE merchant_id=$1))");

  qs = GNUNET_PQ_eval_prepared_multi_select (pg->conn,
                                             "lookup_reserve_rewards",
                                             params,
                                             &lookup_reserve_rewards_cb,
                                             &ltc);
  if (qs < 0)
    return qs;
  if (ltc.qs >= 0)
  {
    cb (cb_cls,
        creation_time,
        expiration_time,
        &merchant_initial_balance,
        &exchange_initial_balance,
        &pickup_amount,
        &committed_amount,
        active,
        &master_pub,
        exchange_url,
        ltc.rewards_length,
        ltc.rewards);
  }
  for (unsigned int i = 0; i<ltc.rewards_length; i++)
    GNUNET_free (ltc.rewards[i].reason);
  GNUNET_array_grow (ltc.rewards,
                     ltc.rewards_length,
                     0);
  GNUNET_PQ_cleanup_result (rs);
  return ltc.qs;
}