/*
   This file is part of TALER
   Copyright (C) 2022 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 exchangedb/pg_get_global_fees.c
 * @brief Implementation of the get_global_fees function for Postgres
 * @author Christian Grothoff
 */
#include "platform.h"
#include "taler_error_codes.h"
#include "taler_dbevents.h"
#include "taler_pq_lib.h"
#include "pg_get_global_fees.h"
#include "pg_helper.h"


/**
 * Closure for #global_fees_cb().
 */
struct GlobalFeeContext
{
  /**
   * Function to call for each global fee block.
   */
  TALER_EXCHANGEDB_GlobalFeeCallback cb;

  /**
   * Closure to give to @e rec.
   */
  void *cb_cls;

  /**
   * Plugin context.
   */
  struct PostgresClosure *pg;

  /**
   * Set to #GNUNET_SYSERR on error.
   */
  enum GNUNET_GenericReturnValue status;
};


/**
 * Function to be called with the results of a SELECT statement
 * that has returned @a num_results results.
 *
 * @param cls closure
 * @param result the postgres result
 * @param num_results the number of results in @a result
 */
static void
global_fees_cb (void *cls,
                PGresult *result,
                unsigned int num_results)
{
  struct GlobalFeeContext *gctx = cls;
  struct PostgresClosure *pg = gctx->pg;

  for (unsigned int i = 0; i<num_results; i++)
  {
    struct TALER_GlobalFeeSet fees;
    struct GNUNET_TIME_Relative purse_timeout;
    struct GNUNET_TIME_Relative history_expiration;
    uint32_t purse_account_limit;
    struct GNUNET_TIME_Timestamp start_date;
    struct GNUNET_TIME_Timestamp end_date;
    struct TALER_MasterSignatureP master_sig;
    struct GNUNET_PQ_ResultSpec rs[] = {
      GNUNET_PQ_result_spec_timestamp ("start_date",
                                       &start_date),
      GNUNET_PQ_result_spec_timestamp ("end_date",
                                       &end_date),
      TALER_PQ_RESULT_SPEC_AMOUNT ("history_fee",
                                   &fees.history),
      TALER_PQ_RESULT_SPEC_AMOUNT ("account_fee",
                                   &fees.account),
      TALER_PQ_RESULT_SPEC_AMOUNT ("purse_fee",
                                   &fees.purse),
      GNUNET_PQ_result_spec_relative_time ("purse_timeout",
                                           &purse_timeout),
      GNUNET_PQ_result_spec_relative_time ("history_expiration",
                                           &history_expiration),
      GNUNET_PQ_result_spec_uint32 ("purse_account_limit",
                                    &purse_account_limit),
      GNUNET_PQ_result_spec_auto_from_type ("master_sig",
                                            &master_sig),
      GNUNET_PQ_result_spec_end
    };
    if (GNUNET_OK !=
        GNUNET_PQ_extract_result (result,
                                  rs,
                                  i))
    {
      GNUNET_break (0);
      gctx->status = GNUNET_SYSERR;
      break;
    }
    gctx->cb (gctx->cb_cls,
              &fees,
              purse_timeout,
              history_expiration,
              purse_account_limit,
              start_date,
              end_date,
              &master_sig);
    GNUNET_PQ_cleanup_result (rs);
  }
}


enum GNUNET_DB_QueryStatus
TEH_PG_get_global_fees (void *cls,
                        TALER_EXCHANGEDB_GlobalFeeCallback cb,
                        void *cb_cls)
{
  struct PostgresClosure *pg = cls;
  struct GNUNET_TIME_Timestamp date
    = GNUNET_TIME_absolute_to_timestamp (
        GNUNET_TIME_absolute_subtract (
          GNUNET_TIME_absolute_get (),
          GNUNET_TIME_UNIT_YEARS));
  struct GNUNET_PQ_QueryParam params[] = {
    GNUNET_PQ_query_param_timestamp (&date),
    GNUNET_PQ_query_param_end
  };
  struct GlobalFeeContext gctx = {
    .cb = cb,
    .cb_cls = cb_cls,
    .pg = pg,
    .status = GNUNET_OK
  };

  /* Used in #postgres_get_global_fees() */
  PREPARE (pg,
           "get_global_fees",
           "SELECT "
           " start_date"
           ",end_date"
           ",history_fee_val"
           ",history_fee_frac"
           ",account_fee_val"
           ",account_fee_frac"
           ",purse_fee_val"
           ",purse_fee_frac"
           ",purse_timeout"
           ",history_expiration"
           ",purse_account_limit"
           ",master_sig"
           " FROM global_fee"
           " WHERE start_date >= $1");

  return GNUNET_PQ_eval_prepared_multi_select (pg->conn,
                                               "get_global_fees",
                                               params,
                                               &global_fees_cb,
                                               &gctx);
}