/*
 dcc.c : irssi

    Copyright (C) 1999-2001 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 "network.h"
#include "line-split.h"
#include "misc.h"
#include "settings.h"
#include "ignore.h"
#include "levels.h"

#include "irc-servers.h"
#include "servers-setup.h"

#include "dcc-chat.h"
#include "dcc-get.h"
#include "dcc-send.h"

void dcc_resume_init(void);
void dcc_resume_deinit(void);

void dcc_autoget_init(void);
void dcc_autoget_deinit(void);

GSList *dcc_conns;

static GSList *dcc_types;
static int dcc_timeouttag;

void dcc_register_type(const char *type)
{
        dcc_types = g_slist_append(dcc_types, g_strdup(type));
}

void dcc_unregister_type(const char *type)
{
	GSList *pos;

	pos = gslist_find_string(dcc_types, type);
	if (pos != NULL) {
		g_free(pos->data);
                dcc_types = g_slist_remove(dcc_types, pos->data);
	}
}

int dcc_str2type(const char *str)
{
	if (gslist_find_string(dcc_types, str) == NULL)
		return -1;

        return module_get_uniq_id_str("DCC", str);
}

/* Initialize DCC record */
void dcc_init_rec(DCC_REC *dcc, IRC_SERVER_REC *server, CHAT_DCC_REC *chat,
		  const char *nick, const char *arg)
{
	g_return_if_fail(dcc != NULL);
	g_return_if_fail(nick != NULL);
	g_return_if_fail(arg != NULL);
	g_return_if_fail(server != NULL || chat != NULL);

        MODULE_DATA_INIT(dcc);
	dcc->created = time(NULL);
	dcc->chat = chat;
	dcc->arg = g_strdup(arg);
	dcc->nick = g_strdup(nick);
	dcc->tagconn = dcc->tagread = dcc->tagwrite = -1;
	dcc->server = server;
	dcc->mynick = g_strdup(server != NULL ? server->nick :
			       chat != NULL ? chat->nick : "??");

	dcc->servertag = server != NULL ? g_strdup(server->tag) :
		(chat == NULL ? NULL : g_strdup(chat->servertag));

	dcc_conns = g_slist_append(dcc_conns, dcc);
	signal_emit("dcc created", 1, dcc);
}

/* Destroy DCC record */
void dcc_destroy(DCC_REC *dcc)
{
	g_return_if_fail(dcc != NULL);
	if (dcc->destroyed) return;

	dcc_conns = g_slist_remove(dcc_conns, dcc);

	dcc->destroyed = TRUE;
	signal_emit("dcc destroyed", 1, dcc);

	if (dcc->handle != NULL) net_disconnect(dcc->handle);
	if (dcc->tagconn != -1) g_source_remove(dcc->tagconn);
	if (dcc->tagread != -1) g_source_remove(dcc->tagread);
	if (dcc->tagwrite != -1) g_source_remove(dcc->tagwrite);

        MODULE_DATA_DEINIT(dcc);
	g_free_not_null(dcc->servertag);
	g_free_not_null(dcc->target);
	g_free(dcc->mynick);
	g_free(dcc->nick);
	g_free(dcc->arg);
	g_free(dcc);
}

DCC_REC *dcc_find_request_latest(int type)
{
	DCC_REC *latest;
        GSList *tmp;

        latest = NULL;
	for (tmp = dcc_conns; tmp != NULL; tmp = tmp->next) {
		DCC_REC *dcc = tmp->data;

		if (dcc->type == type && dcc_is_waiting_user(dcc))
			latest = dcc;
	}

        return latest;
}

DCC_REC *dcc_find_request(int type, const char *nick, const char *arg)
{
	GSList *tmp;

	g_return_val_if_fail(nick != NULL, NULL);

	for (tmp = dcc_conns; tmp != NULL; tmp = tmp->next) {
		DCC_REC *dcc = tmp->data;

		if (dcc->type == type && !dcc_is_connected(dcc) &&
		    g_strcasecmp(dcc->nick, nick) == 0 &&
		    (arg == NULL || strcmp(dcc->arg, arg) == 0))
			return dcc;
	}

	return NULL;
}

void dcc_ip2str(IPADDR *ip, char *host)
{
	IPADDR temp_ip;
	unsigned long addr;

	if (*settings_get_str("dcc_own_ip") != '\0') {
                /* overridden IP address */
		net_host2ip(settings_get_str("dcc_own_ip"), &temp_ip);
                ip = &temp_ip;
	}

	if (IPADDR_IS_V6(ip)) {
		/* IPv6 */
		net_ip2host(ip, host);
	} else {
		memcpy(&addr, &ip->ip, 4);
		g_snprintf(host, MAX_IP_LEN, "%lu",
			   (unsigned long) htonl(addr));
	}
}

void dcc_str2ip(const char *str, IPADDR *ip)
{
	unsigned long addr;

	if (strchr(str, ':') == NULL) {
		/* normal IPv4 address in 32bit number form */
                addr = strtoul(str, NULL, 10);
		ip->family = AF_INET;
		addr = (unsigned long) ntohl(addr);
		memcpy(&ip->ip, &addr, 4);
	} else {
		/* IPv6 - in standard form */
		net_host2ip(str, ip);
	}
}

/* Start listening for incoming connections */
GIOChannel *dcc_listen(GIOChannel *iface, IPADDR *ip, int *port)
{
        GIOChannel *handle;
        const char *dcc_port, *p;
	int first, last;

	if (net_getsockname(iface, ip, NULL) == -1)
		return NULL;

        /* get first port */
	dcc_port = settings_get_str("dcc_port");
	first = atoi(dcc_port);
	if (first == 0) {
                /* random port */
		*port = 0;
		return net_listen(NULL, port);
	}

        /* get last port */
	p = strchr(dcc_port, ' ');
	if (p == NULL) p = strchr(dcc_port, '-');

	dcc_port = p;
	if (dcc_port == NULL)
		last = first;
	else {
		last = atoi(dcc_port+1);
		if (last == 0)
			last = first;
	}

        /* use the first available port */
	for (*port = first; *port <= last; (*port)++) {
		handle = net_listen(NULL, port);
		if (handle != NULL)
                        return handle;
	}

        return NULL;
}

/* Connect to specified IP address using the correct own_ip. */
GIOChannel *dcc_connect_ip(IPADDR *ip, int port)
{
	IPADDR *own_ip, temp_ip;

	if (*settings_get_str("dcc_own_ip") == '\0') {
		own_ip = IPADDR_IS_V6(ip) ? source_host_ip6 : source_host_ip4;
	} else {
                /* use the specified interface for connecting */
		net_host2ip(settings_get_str("dcc_own_ip"), &temp_ip);
                own_ip = &temp_ip;
	}

	return net_connect_ip(ip, port, own_ip);
}

/* Server connected - update server for DCC records that have
   the same server tag */
static void sig_server_connected(IRC_SERVER_REC *server)
{
	GSList *tmp;

	g_return_if_fail(server != NULL);

	for (tmp = dcc_conns; tmp != NULL; tmp = tmp->next) {
		DCC_REC *dcc = tmp->data;

		if (dcc->server == NULL && dcc->servertag != NULL &&
		    g_strcasecmp(dcc->servertag, server->tag) == 0) {
			dcc->server = server;
			g_free(dcc->mynick);
			dcc->mynick = g_strdup(server->nick);
		}
	}
}

/* Server disconnected, remove it from all DCC records */
static void sig_server_disconnected(IRC_SERVER_REC *server)
{
	GSList *tmp;

	g_return_if_fail(server != NULL);

	for (tmp = dcc_conns; tmp != NULL; tmp = tmp->next) {
		DCC_REC *dcc = tmp->data;

		if (dcc->server == server)
                        dcc->server = NULL;
	}
}

/* Your nick changed, change nick in all DCC records */
static void sig_server_nick_changed(IRC_SERVER_REC *server)
{
        GSList *tmp;

        if (!IS_IRC_SERVER(server)) return;

	for (tmp = dcc_conns; tmp != NULL; tmp = tmp->next) {
		DCC_REC *dcc = tmp->data;

		if (dcc->server == server) {
			g_free(dcc->mynick);
			dcc->mynick = g_strdup(server->nick);
		}
	}
}

/* handle emitting "ctcp msg dcc" signal - don't use it directly because
   with /IGNORE * CTCPS we'd be ignored */
static void ctcp_msg(IRC_SERVER_REC *server, const char *data,
		     const char *nick, const char *addr, const char *target)
{
	if (g_strncasecmp(data, "dcc ", 4) != 0)
                return;
	data += 4;

	signal_emit("ctcp msg dcc", 5, server, data, nick, addr, target);
        signal_stop();
}

/* handle emitting "ctcp reply dcc" signal - don't use it directly because
   with /IGNORE * CTCPS we'd be ignored */
static void ctcp_reply(IRC_SERVER_REC *server, const char *data,
		       const char *nick, const char *addr, const char *target)
{
	if (g_strncasecmp(data, "dcc ", 4) != 0)
                return;
	data += 4;

	signal_emit("ctcp reply dcc", 5, server, data, nick, addr, target);
        signal_stop();
}

/* Handle incoming DCC CTCP messages - either from IRC server or DCC chat */
static void ctcp_msg_dcc(IRC_SERVER_REC *server, const char *data,
			 const char *nick, const char *addr,
			 const char *target, DCC_REC *chat)
{
	char *args, *str;

	if (ignore_check(SERVER(server), nick, addr, target, data, MSGLEVEL_DCC))
		return;

	str = g_strconcat("ctcp msg dcc ", data, NULL);
	args = strchr(str+13, ' ');
	if (args != NULL) *args++ = '\0'; else args = "";

	g_strdown(str+13);
	if (!signal_emit(str, 6, server, args, nick, addr, target, chat)) {
		signal_emit("default ctcp msg dcc", 6,
			    server, data, nick, addr, target, chat);
	}
	g_free(str);
}

/* Handle incoming DCC CTCP replies - either from IRC server or DCC chat */
static void ctcp_reply_dcc(IRC_SERVER_REC *server, const char *data,
			   const char *nick, const char *addr,
			   const char *target)
{
	char *args, *str;

	if (ignore_check(SERVER(server), nick, addr, target, data, MSGLEVEL_DCC))
		return;

	str = g_strconcat("ctcp reply dcc ", data, NULL);
	args = strchr(str+15, ' ');
	if (args != NULL) *args++ = '\0'; else args = "";

	g_strdown(str+15);
	if (!signal_emit(str, 5, server, args, nick, addr, target)) {
		signal_emit("default ctcp reply dcc", 5,
			    server, data, nick, addr, target);
	}
	g_free(str);
}

/* CTCP REPLY: REJECT */
static void ctcp_reply_dcc_reject(IRC_SERVER_REC *server, const char *data,
				  const char *nick, const char *addr,
				  DCC_REC *chat)
{
        DCC_REC *dcc;
	char *type, *args;

	type = g_strdup(data);
	args = strchr(type, ' ');
        if (args != NULL) *args++ = '\0'; else args = "";

	dcc = dcc_find_request(dcc_str2type(type), nick, args);
	if (dcc != NULL) dcc_close(dcc);

        g_free(type);
}

void dcc_close(DCC_REC *dcc)
{
	signal_emit("dcc closed", 1, dcc);
        dcc_destroy(dcc);
}

/* Reject a DCC request */
void dcc_reject(DCC_REC *dcc, IRC_SERVER_REC *server)
{
	g_return_if_fail(dcc != NULL);

	signal_emit("dcc rejected", 1, dcc);

	if (dcc->server != NULL)
		server = dcc->server;

	if (server != NULL && dcc_is_connected(dcc)) {
		irc_send_cmdv(server, "NOTICE %s :\001DCC REJECT %s %s\001",
			      dcc->nick, dcc_type2str(dcc->orig_type),
			      dcc->arg);
	}

	dcc_close(dcc);
}

static int dcc_timeout_func(void)
{
	GSList *tmp, *next;
	time_t now;

	now = time(NULL)-settings_get_int("dcc_timeout");
	for (tmp = dcc_conns; tmp != NULL; tmp = next) {
		DCC_REC *dcc = tmp->data;

		next = tmp->next;
		if (dcc->tagread == -1 && now > dcc->created) {
			/* Timed out - don't send DCC REJECT CTCP so CTCP
			   flooders won't affect us and it really doesn't
			   matter that much anyway if the other side doen't
			   get it.. */
			dcc_close(dcc);
		}
	}

	return 1;
}

static void event_no_such_nick(IRC_SERVER_REC *server, char *data)
{
	char *params, *nick;
	GSList *tmp, *next;

	g_return_if_fail(data != NULL);

	params = event_get_params(data, 2, NULL, &nick);

	/* check if we've send any dcc requests to this nick.. */
	for (tmp = dcc_conns; tmp != NULL; tmp = next) {
		DCC_REC *dcc = tmp->data;

		next = tmp->next;
		if (!dcc_is_connected(dcc) && dcc->server == server &&
		    g_strcasecmp(dcc->nick, nick) == 0)
			dcc_close(dcc);
	}

	g_free(params);
}

/* SYNTAX: DCC CLOSE <type> <nick> [<file>] */
static void cmd_dcc_close(char *data, IRC_SERVER_REC *server)
{
	GSList *tmp, *next;
	char *typestr, *nick, *arg;
	void *free_arg;
	int found, type;

	g_return_if_fail(data != NULL);

	if (!cmd_get_params(data, &free_arg, 3 | PARAM_FLAG_GETREST,
			    &typestr, &nick, &arg))
		return;

	if (*nick == '\0') cmd_param_error(CMDERR_NOT_ENOUGH_PARAMS);

	g_strup(typestr);
	type = dcc_str2type(typestr);
	if (type == -1) {
		signal_emit("dcc error unknown type", 1, typestr);
		cmd_params_free(free_arg);
		return;
	}

	found = FALSE;
	for (tmp = dcc_conns; tmp != NULL; tmp = next) {
		DCC_REC *dcc = tmp->data;

		next = tmp->next;
		if (dcc->type == type && g_strcasecmp(dcc->nick, nick) == 0 &&
		    (*arg == '\0' || strcmp(dcc->arg, arg) == 0)) {
			dcc_reject(dcc, server);
			found = TRUE;
		}
	}

	if (!found) {
		signal_emit("dcc error close not found", 3,
			    typestr, nick, arg);
	}

	cmd_params_free(free_arg);
}

static void cmd_dcc(const char *data, IRC_SERVER_REC *server, void *item)
{
	command_runsub("dcc", data, server, item);
}

void irc_dcc_init(void)
{
	dcc_conns = NULL;
	dcc_timeouttag = g_timeout_add(1000, (GSourceFunc) dcc_timeout_func, NULL);

	settings_add_str("dcc", "dcc_port", "0");
	settings_add_int("dcc", "dcc_timeout", 300);
	settings_add_str("dcc", "dcc_own_ip", "");

	signal_add("server connected", (SIGNAL_FUNC) sig_server_connected);
	signal_add("server disconnected", (SIGNAL_FUNC) sig_server_disconnected);
	signal_add("server nick changed", (SIGNAL_FUNC) sig_server_nick_changed);
	signal_add("ctcp msg", (SIGNAL_FUNC) ctcp_msg);
	signal_add("ctcp reply", (SIGNAL_FUNC) ctcp_reply);
	signal_add("ctcp msg dcc", (SIGNAL_FUNC) ctcp_msg_dcc);
	signal_add("ctcp reply dcc", (SIGNAL_FUNC) ctcp_reply_dcc);
	signal_add("ctcp reply dcc reject", (SIGNAL_FUNC) ctcp_reply_dcc_reject);
	signal_add("event 401", (SIGNAL_FUNC) event_no_such_nick);
	command_bind("dcc", NULL, (SIGNAL_FUNC) cmd_dcc);
	command_bind("dcc close", NULL, (SIGNAL_FUNC) cmd_dcc_close);

	dcc_chat_init();
	dcc_get_init();
	dcc_send_init();
	dcc_resume_init();
	dcc_autoget_init();

	module_register("dcc", "irc");
}

void irc_dcc_deinit(void)
{
	while (dcc_conns != NULL)
		dcc_destroy(dcc_conns->data);

	dcc_chat_deinit();
	dcc_get_deinit();
	dcc_send_deinit();
	dcc_resume_deinit();
	dcc_autoget_deinit();

	signal_remove("server connected", (SIGNAL_FUNC) sig_server_connected);
	signal_remove("server disconnected", (SIGNAL_FUNC) sig_server_disconnected);
	signal_remove("server nick changed", (SIGNAL_FUNC) sig_server_nick_changed);
	signal_remove("ctcp msg", (SIGNAL_FUNC) ctcp_msg);
	signal_remove("ctcp reply", (SIGNAL_FUNC) ctcp_reply);
	signal_remove("ctcp msg dcc", (SIGNAL_FUNC) ctcp_msg_dcc);
	signal_remove("ctcp reply dcc", (SIGNAL_FUNC) ctcp_reply_dcc);
	signal_remove("ctcp reply dcc reject", (SIGNAL_FUNC) ctcp_reply_dcc_reject);
	signal_remove("event 401", (SIGNAL_FUNC) event_no_such_nick);
	command_unbind("dcc", (SIGNAL_FUNC) cmd_dcc);
	command_unbind("dcc close", (SIGNAL_FUNC) cmd_dcc_close);

	g_source_remove(dcc_timeouttag);
}