/* vim: set expandtab ts=4 sw=4: */
/*
 * You may redistribute this program and/or modify it under the terms of
 * the GNU General Public License as published by the Free Software Foundation,
 * either version 3 of the License, or (at your option) any later version.
 *
 * This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
 */
#ifndef AverageRoller_H
#define AverageRoller_H

#include "memory/Allocator.h"

#include <stdint.h>
#include "util/events/EventBase.h"
#include "util/Linker.h"
Linker_require("util/AverageRoller.c");

struct AverageRoller
{
    int unused;
};

/**
 * Create a new AverageRoller.
 *
 * @param windowSeconds the number of seconds the average should run over.
 * @return a new roller.
 */
struct AverageRoller* AverageRoller_new(const uint32_t windowSeconds,
                                        struct EventBase* eventBase,
                                        struct Allocator* allocator);

/**
 * Get the average.
 *
 * @param roller the roller context created by AverageRoller_new()
 * @return the average over the last windowSeconds active seconds.
 */
uint32_t AverageRoller_getAverage(struct AverageRoller* roller);

/**
 * Update the roller with a new entry at a manually specified point in time.
 *
 * @param averageRoller the roller to update.
 * @param now the number of seconds since the epoch.
 * @param newEntry the a new number to be factored into the average.
 * @return the average over the last windowSeconds seconds.
 */
uint32_t AverageRoller_updateAtTime(struct AverageRoller* averageRoller,
                                    const uint64_t now,
                                    const uint32_t newEntry);

/**
 * Update the roller with a new entry and get the average.
 * If there are no new updates then past seconds do not get trimmed off and
 * the average stays the same. This, though destroying its mathmatical correctness,
 * provides some forgiveness to the average since it will not drop to 0 if windowSeconds
 * seconds elapse with no update.
 *
 * @param roller the roller context created by AverageRoller_new()
 * @param newEntry the a new number to be factored into the average.
 * @return the average over the last windowSeconds active seconds.
 */
uint32_t AverageRoller_update(struct AverageRoller* roller, const uint32_t newEntry);

#endif
