/*
 netsplit.c : irssi

    Copyright (C) 1999 Timo Sirainen

    This program 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 2 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, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "module.h"
#include "signals.h"
#include "commands.h"
#include "misc.h"
#include "common-setup.h"

#include "irc-server.h"
#include "netsplit.h"

static int split_tag;

static NETSPLIT_SERVER_REC *netsplit_server_find(IRC_SERVER_REC *server, const char *servername, const char *destserver)
{
	GSList *tmp;

	for (tmp = server->split_servers; tmp != NULL; tmp = tmp->next) {
		NETSPLIT_SERVER_REC *rec = tmp->data;

		if (g_strcasecmp(rec->server, servername) == 0 &&
		    g_strcasecmp(rec->destserver, destserver) == 0)
			return rec;
	}

	return NULL;
}

static NETSPLIT_SERVER_REC *netsplit_server_create(IRC_SERVER_REC *server, const char *servername, const char *destserver)
{
	NETSPLIT_SERVER_REC *rec;

	rec = netsplit_server_find(server, servername, destserver);
	if (rec != NULL) return rec;

	rec = g_new0(NETSPLIT_SERVER_REC, 1);
	rec->server = g_strdup(servername);
	rec->destserver = g_strdup(destserver);

	server->split_servers = g_slist_append(server->split_servers, rec);
	signal_emit("netsplit new server", 2, server, rec);
	return rec;
}

static void netsplit_destroy_server(IRC_SERVER_REC *server, NETSPLIT_SERVER_REC *rec)
{
	server->split_servers = g_slist_remove(server->split_servers, rec);

        g_free(rec->server);
	g_free(rec->destserver);
	g_free(rec);
}

static NETSPLIT_REC *netsplit_add(IRC_SERVER_REC *server, const char *nick, const char *address, const char *servers)
{
	NETSPLIT_REC *rec;
	NETSPLIT_CHAN_REC *splitchan;
	NICK_REC *nickrec;
	GSList *tmp;
	char *p, *dupservers;

	g_return_val_if_fail(server != NULL, NULL);
	g_return_val_if_fail(nick != NULL, NULL);
	g_return_val_if_fail(address != NULL, NULL);

	/* get splitted servers */
	dupservers = g_strdup(servers);
	p = strchr(dupservers, ' ');
	if (p == NULL) {
		g_free(dupservers);
		g_return_val_if_fail(p != NULL, NULL);
	}
	*p++ = '\0';

	rec = g_new0(NETSPLIT_REC, 1);
	rec->nick = g_strdup(nick);
	rec->address = g_strdup(address);
	rec->destroy = time(NULL)+NETSPLIT_MAX_REMEMBER;

	rec->server = netsplit_server_create(server, dupservers, p);
	rec->server->count++;
	g_free(dupservers);

	/* copy the channel nick records.. */
	for (tmp = server->channels; tmp != NULL; tmp = tmp->next) {
		CHANNEL_REC *channel = tmp->data;

		nickrec = nicklist_find(channel, nick);
		if (nickrec == NULL)
			continue;

		splitchan = g_new0(NETSPLIT_CHAN_REC, 1);
		splitchan->name = g_strdup(channel->name);
		memcpy(&splitchan->nick, nickrec, sizeof(NICK_REC));

		rec->channels = g_slist_append(rec->channels, splitchan);
	}

	g_hash_table_insert(server->splits, rec->nick, rec);

	signal_emit("netsplit add", 1, rec);
	return rec;
}

static void netsplit_destroy(IRC_SERVER_REC *server, NETSPLIT_REC *rec)
{
	GSList *tmp;

	g_return_if_fail(rec != NULL);

	signal_emit("netsplit remove", 1, rec);
	for (tmp = rec->channels; tmp != NULL; tmp = tmp->next) {
		NETSPLIT_CHAN_REC *rec = tmp->data;

		g_free(rec->name);
		g_free(rec);
	}

	if (--rec->server->count == 0)
		netsplit_destroy_server(server, rec->server);

	g_free(rec->nick);
	g_free(rec->address);
	g_free(rec);
}

static void netsplit_destroy_hash(void *key, NETSPLIT_REC *rec, IRC_SERVER_REC *server)
{
	netsplit_destroy(server, rec);
}

NETSPLIT_REC *netsplit_find(IRC_SERVER_REC *server, const char *nick, const char *address)
{
	NETSPLIT_REC *rec;

	g_return_val_if_fail(server != NULL, NULL);
	g_return_val_if_fail(nick != NULL, NULL);

	rec = g_hash_table_lookup(server->splits, nick);
	if (rec == NULL) return NULL;

	return (address == NULL || g_strcasecmp(rec->address, address) == 0) ? rec : NULL;
}

NICK_REC *netsplit_find_channel(IRC_SERVER_REC *server, const char *nick, const char *address, const char *channel)
{
	NETSPLIT_REC *rec;
	GSList *tmp;

	rec = netsplit_find(server, nick, address);
	if (rec == NULL) return NULL;

	for (tmp = rec->channels; tmp != NULL; tmp = tmp->next) {
		NETSPLIT_CHAN_REC *rec = tmp->data;

		if (g_strcasecmp(rec->name, channel) == 0)
			return &rec->nick;
	}

	return NULL;
}

int quitmsg_is_split(const char *msg)
{
	char *params, *host1, *host2, *p;
	int ok;

	g_return_val_if_fail(msg != NULL, FALSE);

	/* must have only two words */
	p = strchr(msg, ' ');
	if (p == NULL || strchr(p+1, ' ') != NULL) return FALSE;

	/* check that it looks ok.. */
	if (!match_wildcards("*.* *.*", msg) ||
	    match_wildcards("*..*", msg) || strstr(msg, "))") != NULL)
		return FALSE;

	/* get the two hosts */
	ok = FALSE;
	params = cmd_get_params(msg, 2, &host1, &host2);
	if (g_strcasecmp(host1, host2) != 0) { /* hosts can't be same.. */
		/* check that domain length is 2 or 3 */
		p = strrchr(host1, '.');
		if (p != NULL && (strlen(p+1) == 2 || strlen(p+1) == 3)) {
			p = strrchr(host2, '.');
			if (p != NULL && (strlen(p+1) == 2 || strlen(p+1) == 3)) {
				/* it looks just like a netsplit to me. */
				ok = TRUE;
			}
		}
	}
	g_free(params);

	return ok;
}

static void split_set_timeout(void *key, NETSPLIT_REC *rec, NETSPLIT_REC *orig)
{
	if (rec == orig) {
		/* original nick, destroy it in a few seconds.. */
		rec->destroy = time(NULL)+4;
	} else if (g_strcasecmp(rec->server->server, orig->server->server) == 0 &&
		 g_strcasecmp(rec->server->destserver, orig->server->destserver) == 0) {
		/* same servers -> split over -> destroy old records sooner.. */
		rec->destroy = time(NULL)+60;
	}
}

static void event_join(const char *data, IRC_SERVER_REC *server, const char *nick, const char *address)
{
	NETSPLIT_REC *rec;

	/* check if split is over */
	rec = g_hash_table_lookup(server->splits, nick);
	if (rec == NULL) return;

	if (g_strcasecmp(rec->address, address) == 0) {
		/* yep, looks like it is. for same people that had the same
		   splitted servers set the timeout to one minute.

		   .. if the user just changed server, he/she can't use the
		   same nick (unless the server is broken) so don't bother
		   checking that the nick's server matches the split. */
		g_hash_table_foreach(server->splits, (GHFunc) split_set_timeout, rec);
	} else {
		/* back from different address.. just destroy it. */
		g_hash_table_remove(server->splits, rec->nick);
		netsplit_destroy(server, rec);
	}
}

static void event_quit(const char *data, IRC_SERVER_REC *server, const char *nick, const char *address)
{
	g_return_if_fail(data != NULL);

	if (*data == ':') data++;
	if (g_strcasecmp(nick, server->nick) != 0 && quitmsg_is_split(data)) {
		/* netsplit! */
		netsplit_add(server, nick, address, data);
	}
}

static void sig_disconnected(IRC_SERVER_REC *server)
{
	g_return_if_fail(server != NULL);

	g_hash_table_foreach(server->splits, (GHFunc) netsplit_destroy_hash, server);
	g_hash_table_destroy(server->splits);
}

static int split_server_check(void *key, NETSPLIT_REC *rec, IRC_SERVER_REC *server)
{
	/* Check if this split record is too old.. */
	if (rec->destroy > time(NULL))
		return FALSE;

	netsplit_destroy(server, rec);
	return TRUE;
}

static int split_check_old(void)
{
	GSList *tmp;

	for (tmp = servers; tmp != NULL; tmp = tmp->next) {
		IRC_SERVER_REC *server = tmp->data;

		g_hash_table_foreach_remove(server->splits, (GHRFunc) split_server_check, server);
	}

	return 1;
}

void netsplit_init(void)
{
	split_tag = g_timeout_add(1000, (GSourceFunc) split_check_old, NULL);
	signal_add_first("event join", (SIGNAL_FUNC) event_join);
	signal_add_first("event quit", (SIGNAL_FUNC) event_quit);
	signal_add("server disconnected", (SIGNAL_FUNC) sig_disconnected);
}

void netsplit_deinit(void)
{
	GSList *tmp;

	for (tmp = servers; tmp != NULL; tmp = tmp->next)
		sig_disconnected(tmp->data);

	g_source_remove(split_tag);
	signal_remove("event join", (SIGNAL_FUNC) event_join);
	signal_remove("event quit", (SIGNAL_FUNC) event_quit);
	signal_remove("server disconnected", (SIGNAL_FUNC) sig_disconnected);
}