/*
   This file is part of TALER
   Copyright (C) 2025 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 src/include/merchant-database/iterate_statistic_interval_counters.h
 * @brief implementation of the iterate_statistic_interval_counters function for Postgres
 * @author Martin Schanzenbach
 */
#ifndef MERCHANT_DATABASE_ITERATE_STATISTIC_INTERVAL_COUNTERS_H
#define MERCHANT_DATABASE_ITERATE_STATISTIC_INTERVAL_COUNTERS_H

#include <taler/taler_util.h>
#include <taler/taler_json_lib.h>
#include "merchantdb_lib.h"


/**
 * Details about a statistic with counter.
 */
struct TALER_MERCHANTDB_StatisticsCounterByIntervalDetails
{
  /**
   * Start time of the interval.
   * The interval always ends at the response generation time.
   */
  struct GNUNET_TIME_Timestamp start_time;

  /**
   * Sum of all counters falling under the given
   * SLUG within this timeframe
   */
  uint64_t cumulative_counter;
};


/**
 * Function returning integer-valued statistics for a time interval.
 * Called by `iterate_statistic_interval_counters`.
 *
 * @param cls closure
 * @param description description of the statistic
 * @param interval_start start time of the interval
 * @param cumulative_counter counter value
 */
typedef void
(*TALER_MERCHANTDB_CounterByIntervalStatisticsCallback)(
  void *cls,
  const char *description,
  struct GNUNET_TIME_Timestamp interval_start,
  uint64_t cumulative_counter);

/**
 * Lookup statistics where the values are counters.
 *
 * @param pg database context
 * @param instance_id instance to lookup statistics for
 * @param slug slug to lookup statistics for
 * @param cb function to call on all statistics found
 * @param cb_cls closure for @a cb
 * @return database result code
 */
enum GNUNET_DB_QueryStatus
TALER_MERCHANTDB_iterate_statistic_interval_counters (
  struct TALER_MERCHANTDB_PostgresContext *pg,
  const char *instance_id,
  const char *slug,
  TALER_MERCHANTDB_CounterByIntervalStatisticsCallback cb,
  void *cb_cls);

#endif
