/*
   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_pickup.c
 * @brief Implementation of the lookup_pickup 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_pickup.h"
#include "pg_helper.h"

/**
 * Closure for #lookup_signatures_cb().
 */
struct LookupSignaturesContext
{
  /**
   * Length of the @e sigs array
   */
  unsigned int sigs_length;

  /**
   * Where to store the signatures.
   */
  struct TALER_BlindedDenominationSignature *sigs;
};


/**
 * 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 LookupSignaturesContext *`
 * @param result the postgres result
 * @param num_results the number of results in @a result
 */
static void
lookup_signatures_cb (void *cls,
                      PGresult *result,
                      unsigned int num_results)
{
  struct LookupSignaturesContext *lsc = cls;

  for (unsigned int i = 0; i < num_results; i++)
  {
    uint32_t offset;
    struct TALER_BlindedDenominationSignature bsig;
    struct GNUNET_PQ_ResultSpec rs[] = {
      GNUNET_PQ_result_spec_uint32 ("coin_offset",
                                    &offset),
      TALER_PQ_result_spec_blinded_denom_sig ("blind_sig",
                                              &bsig),
      GNUNET_PQ_result_spec_end
    };

    if (GNUNET_OK !=
        GNUNET_PQ_extract_result (result,
                                  rs,
                                  i))
    {
      GNUNET_break (0);
      return;
    }
    if (offset >= lsc->sigs_length)
    {
      GNUNET_break_op (0);
      GNUNET_PQ_cleanup_result (rs);
      continue;
    }
    /* Must be NULL due to UNIQUE constraint on offset and
       requirement that client launched us with 'sigs'
       pre-initialized to NULL. */
    lsc->sigs[offset] = bsig;
  }
}


enum GNUNET_DB_QueryStatus
TMH_PG_lookup_pickup (void *cls,
                      const char *instance_id,
                      const struct TALER_RewardIdentifierP *reward_id,
                      const struct TALER_PickupIdentifierP *pickup_id,
                      char **exchange_url,
                      struct TALER_ReservePrivateKeyP *reserve_priv,
                      unsigned int sigs_length,
                      struct TALER_BlindedDenominationSignature sigs[])
{
  struct PostgresClosure *pg = cls;
  uint64_t pickup_serial;

  {
    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_auto_from_type (pickup_id),
      GNUNET_PQ_query_param_end
    };
    struct GNUNET_PQ_ResultSpec rs[] = {
      GNUNET_PQ_result_spec_string ("exchange_url",
                                    exchange_url),
      GNUNET_PQ_result_spec_auto_from_type ("reserve_priv",
                                            reserve_priv),
      GNUNET_PQ_result_spec_uint64 ("pickup_serial",
                                    &pickup_serial),
      GNUNET_PQ_result_spec_end
    };
    enum GNUNET_DB_QueryStatus qs;

    check_connection (pg);
    PREPARE (pg,
             "lookup_pickup",
             "SELECT"
             " exchange_url"
             ",reserve_priv"
             ",pickup_serial"
             " FROM merchant_reward_pickups"
             " JOIN merchant_rewards USING (reward_serial)"
             " JOIN merchant_reward_reserves USING (reserve_serial)"
             " JOIN merchant_reward_reserve_keys USING (reserve_serial)"
             " WHERE pickup_id = $3"
             "   AND 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_pickup",
                                                   params,
                                                   rs);
    if (qs <= 0)
      return qs;
  }
  {
    struct GNUNET_PQ_QueryParam params[] = {
      GNUNET_PQ_query_param_uint64 (&pickup_serial),
      GNUNET_PQ_query_param_end
    };
    struct LookupSignaturesContext lsc = {
      .sigs_length = sigs_length,
      .sigs = sigs
    };

    PREPARE (pg,
             "lookup_pickup_signatures",
             "SELECT"
             " coin_offset"
             ",blind_sig"
             " FROM merchant_reward_pickup_signatures"
             " WHERE pickup_serial = $1");

    return GNUNET_PQ_eval_prepared_multi_select (pg->conn,
                                                 "lookup_pickup_signatures",
                                                 params,
                                                 &lookup_signatures_cb,
                                                 &lsc);
  }
}