/*
 * Copyright (c) 2015 Red Hat, Inc.
 *
 * All rights reserved.
 *
 * Author: Jan Friesse (jfriesse@redhat.com)
 *
 * This software licensed under BSD license, the text of which follows:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * - Neither the name of the Red Hat, Inc. nor the names of its
 *   contributors may be used to endorse or promote products derived from this
 *   software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <string.h>
#include <assert.h>

#include "timer-list.h"

void
timer_list_init(struct timer_list *tlist)
{

	memset(tlist, 0, sizeof(*tlist));

	TAILQ_INIT(&tlist->list);
	TAILQ_INIT(&tlist->free_list);
}

struct timer_list_entry *
timer_list_add(struct timer_list *tlist, PRUint32 interval, timer_list_cb_fn func, void *data1,
    void *data2)
{
	struct timer_list_entry *entry;

	assert(tlist->list_expire_in_progress == 0);

	if (interval > (0xffffffffUL / 4)) {
		return (NULL);
	}

	if (!TAILQ_EMPTY(&tlist->free_list)) {
		/*
		 * Use free list entry
		 */
		entry = TAILQ_FIRST(&tlist->free_list);
		TAILQ_REMOVE(&tlist->free_list, entry, entries);
	} else {
		/*
		 * Alloc new entry
		 */
		entry = malloc(sizeof(*entry));
		if (entry == NULL) {
			return (NULL);
		}
	}

	memset(entry, 0, sizeof(*entry));
	entry->epoch = PR_IntervalNow();
	entry->interval = interval;
	entry->func = func;
	entry->user_data1 = data1;
	entry->user_data2 = data2;
	TAILQ_INSERT_TAIL(&tlist->list, entry, entries);

	return (entry);
}

void
timer_list_expire(struct timer_list *tlist)
{
	PRIntervalTime now;
	struct timer_list_entry *entry;
	struct timer_list_entry *entry_next;
	PRUint32 delta;
	int res;

	tlist->list_expire_in_progress = 1;

	now = PR_IntervalNow();

	entry = TAILQ_FIRST(&tlist->list);

	while (entry != NULL) {
		entry_next = TAILQ_NEXT(entry, entries);

		delta = PR_IntervalToMilliseconds(now - entry->epoch);
		if (delta >= entry->interval) {
			/*
			 * Expired
			 */
			res = entry->func(entry->user_data1, entry->user_data2);
			if (res == 0) {
				/*
				 * Move item to free list
				 */
				TAILQ_REMOVE(&tlist->list, entry, entries);
				TAILQ_INSERT_HEAD(&tlist->free_list, entry, entries);
			} else {
				/*
				 * Schedule again
				 */
				entry->epoch = now;
			}
		}

		entry = entry_next;
	}

	tlist->list_expire_in_progress = 0;
}

PRIntervalTime
timer_list_time_to_expire(struct timer_list *tlist)
{
	PRIntervalTime now;
	struct timer_list_entry *entry;
	PRUint32 delta;
	PRUint32 timeout;
	PRUint32 min_timeout;
	int min_timeout_set;

	min_timeout_set = 0;

	now = PR_IntervalNow();

	TAILQ_FOREACH(entry, &tlist->list, entries) {
		delta = PR_IntervalToMilliseconds(now - entry->epoch);

		if (delta >= entry->interval) {
			/*
			 * One of timer already expired
			 */
			return (PR_INTERVAL_NO_WAIT);
		}

		timeout = entry->interval - delta;

		if (!min_timeout_set) {
			min_timeout_set = 1;
			min_timeout = timeout;
		}

		if (timeout < min_timeout) {
			min_timeout = timeout;
		}
	}

	if (!min_timeout_set) {
		return (PR_INTERVAL_NO_TIMEOUT);
	}

	return (PR_MillisecondsToInterval(min_timeout));
}

void
timer_list_delete(struct timer_list *tlist, struct timer_list_entry *entry)
{

	assert(tlist->list_expire_in_progress == 0);

	/*
	 * Move item to free list
	 */
	TAILQ_REMOVE(&tlist->list, entry, entries);
	TAILQ_INSERT_HEAD(&tlist->free_list, entry, entries);
}

void
timer_list_free(struct timer_list *tlist)
{
	struct timer_list_entry *entry;
	struct timer_list_entry *entry_next;


	entry = TAILQ_FIRST(&tlist->list);

	while (entry != NULL) {
		entry_next = TAILQ_NEXT(entry, entries);

		free(entry);

		entry = entry_next;
	}

	entry = TAILQ_FIRST(&tlist->free_list);

	while (entry != NULL) {
		entry_next = TAILQ_NEXT(entry, entries);

		free(entry);

		entry = entry_next;
	}

	timer_list_init(tlist);
}