#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <time.h>

#include "gamelist.h"
#include "logging.h"

#define BUCKET_NUM 127

static struct list_head *bucket;

static unsigned int hash_entry(struct game_entry *entry)
{
	unsigned int hash = 0x12345678;

	hash = ((hash << 5) ^ (hash >> 27)) ^ ((entry->ip >>  0) & 0xFF);
	hash = ((hash << 5) ^ (hash >> 27)) ^ ((entry->ip >>  8) & 0xFF);
	hash = ((hash << 5) ^ (hash >> 27)) ^ ((entry->ip >> 16) & 0xFF);
	hash = ((hash << 5) ^ (hash >> 27)) ^ ((entry->ip >> 24) & 0xFF);

	hash = ((hash << 5) ^ (hash >> 27)) ^ ((entry->port1 >> 0) & 0xFF);
	hash = ((hash << 5) ^ (hash >> 27)) ^ ((entry->port1 >> 8) & 0xFF);

	return hash % BUCKET_NUM;
}

static int compare_entry(struct game_entry *a, struct game_entry *b)
{
	return (a->gameid == b->gameid && a->ip == b->ip &&
		a->port1 == b->port1 && a->port2 == b->port2);
}

int gamelist_add(struct game_entry *entry)
{
	unsigned int hash = hash_entry(entry);

	struct game_entry *search;
	list_for_each_entry(search, &bucket[hash], list) {
		if (compare_entry(search, entry)) {
			search->modtime = time(NULL);
			return 0;
		}
	}

	entry->modtime = time(NULL);
	list_add_tail(&entry->list, &bucket[hash]);
	return 0;
}

int gamelist_gc_and_dump(int (*callback)(struct game_entry *entry), int timeout)
{
	long now = time(NULL);
	int i;

	for (i = 0; i < BUCKET_NUM; i++) {
		struct game_entry *entry, *tmp;
		list_for_each_entry_safe(entry, tmp, &bucket[i], list) {
			if (entry->modtime + timeout >= now) {
				callback(entry);

			} else {
				list_del(&entry->list);
				free(entry);
			}
		}
	}
	return 0;
}

int gamelist_init()
{
	bucket = malloc(sizeof(struct list_head) * BUCKET_NUM);
	if (bucket == NULL) {
		log_print(LOG_ERROR, "scan_init(): out of memory");
		return -1;
	}

	int i;
	for (i = 0; i < BUCKET_NUM; i++)
		INIT_LIST_HEAD(&bucket[i]);

	return 0;
}