/*
 * ngIRCd -- The Next Generation IRC Daemon
 * Copyright (c)2001-2012 Alexander Barton (alex@barton.de) and Contributors.
 *
 * 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.
 * Please read the file COPYING, README and AUTHORS for more information.
 */

#include "portab.h"

/**
 * @file
 * IRC commands
 */

#include "imp.h"
#include <assert.h>
#include <stdio.h>
#include <string.h>

#include "ngircd.h"
#include "conn-func.h"
#include "conf.h"
#include "channel.h"
#include "conn-encoding.h"
#include "defines.h"
#include "irc-write.h"
#include "log.h"
#include "match.h"
#include "messages.h"
#include "parse.h"
#include "tool.h"

#include "exp.h"
#include "irc.h"


static char *Option_String PARAMS((CONN_ID Idx));
static bool Send_Message PARAMS((CLIENT *Client, REQUEST *Req, int ForceType,
				 bool SendErrors));
static bool Send_Message_Mask PARAMS((CLIENT *from, char *command,
				      char *targetMask, char *message,
				      bool SendErrors));


/**
 * Check if a list limit is reached and inform client accordingly.
 *
 * @param From The client.
 * @param Count Reply item count.
 * @param Limit Reply limit.
 * @param Name Name of the list.
 * @return true if list limit has been reached; false otherwise.
 */
GLOBAL bool
IRC_CheckListTooBig(CLIENT *From, const int Count, const int Limit,
		    const char *Name)
{
	assert(From != NULL);
	assert(Count >= 0);
	assert(Limit > 0);
	assert(Name != NULL);

	if (Count < Limit)
		return false;

	(void)IRC_WriteStrClient(From,
				 "NOTICE %s :%s list limit (%d) reached!",
				 Client_ID(From), Name, Limit);
	IRC_SetPenalty(From, 2);
	return true;
}


GLOBAL bool
IRC_ERROR( CLIENT *Client, REQUEST *Req )
{
	assert( Client != NULL );
	assert( Req != NULL );

	if (Client_Type(Client) != CLIENT_GOTPASS
	    && Client_Type(Client) != CLIENT_GOTPASS_2813
	    && Client_Type(Client) != CLIENT_UNKNOWNSERVER
	    && Client_Type(Client) != CLIENT_SERVER
	    && Client_Type(Client) != CLIENT_SERVICE) {
		LogDebug("Ignored ERROR command from \"%s\" ...",
			 Client_Mask(Client));
		IRC_SetPenalty(Client, 2);
		return CONNECTED;
	}

	if (Req->argc < 1)
		Log(LOG_NOTICE, "Got ERROR from \"%s\"!",
		    Client_Mask(Client));
	else
		Log(LOG_NOTICE, "Got ERROR from \"%s\": \"%s\"!",
		    Client_Mask(Client), Req->argv[0]);

	return CONNECTED;
} /* IRC_ERROR */


/**
 * Handler for the IRC "KILL" command.
 *
 * This function implements the IRC command "KILL" wich is used to selectively
 * disconnect clients. It can be used by IRC operators and servers, for example
 * to "solve" nick collisions after netsplits. See RFC 2812 section 3.7.1.
 *
 * Please note that this function is also called internally, without a real
 * KILL command being received over the network! Client is Client_ThisServer()
 * in this case, and the prefix in Req is NULL.
 *
 * @param Client	The client from which this command has been received
 *			or Client_ThisServer() when generated interanlly.
 * @param Req		Request structure with prefix and all parameters.
 * @returns		CONNECTED or DISCONNECTED.
 */
GLOBAL bool
IRC_KILL( CLIENT *Client, REQUEST *Req )
{
	CLIENT *prefix, *c;
	char reason[COMMAND_LEN], *msg;
	CONN_ID my_conn, conn;

	assert (Client != NULL);
	assert (Req != NULL);

	if (Client_Type(Client) != CLIENT_SERVER && !Client_OperByMe(Client))
		return IRC_WriteStrClient(Client, ERR_NOPRIVILEGES_MSG,
					  Client_ID(Client));

	if (Req->argc != 2)
		return IRC_WriteStrClient(Client, ERR_NEEDMOREPARAMS_MSG,
					  Client_ID(Client), Req->command);

	/* Get prefix (origin); use the client if no prefix is given. */
	if (Req->prefix)
		prefix = Client_Search(Req->prefix);
	else
		prefix = Client;

	/* Log a warning message and use this server as origin when the
	 * prefix (origin) is invalid. */
	if (!prefix) {
		Log(LOG_WARNING, "Got KILL with invalid prefix: \"%s\"!",
		    Req->prefix );
		prefix = Client_ThisServer();
	}

	if (Client != Client_ThisServer())
		Log(LOG_NOTICE|LOG_snotice,
		    "Got KILL command from \"%s\" for \"%s\": %s",
		    Client_Mask(prefix), Req->argv[0], Req->argv[1]);

	/* Build reason string: Prefix the "reason" if the originator is a
	 * regular user, so users can't spoof KILLs of servers. */
	if (Client_Type(Client) == CLIENT_USER)
		snprintf(reason, sizeof(reason), "KILLed by %s: %s",
			 Client_ID(Client), Req->argv[1]);
	else
		strlcpy(reason, Req->argv[1], sizeof(reason));

	/* Inform other servers */
	IRC_WriteStrServersPrefix(Client, prefix, "KILL %s :%s",
				  Req->argv[0], reason);

	/* Save ID of this connection */
	my_conn = Client_Conn( Client );

	/* Do we host such a client? */
	c = Client_Search( Req->argv[0] );
	if( c )
	{
		if(( Client_Type( c ) != CLIENT_USER ) &&
		   ( Client_Type( c ) != CLIENT_GOTNICK ))
		{
			/* Target of this KILL is not a regular user, this is
			 * invalid! So we ignore this case if we received a
			 * regular KILL from the network and try to kill the
			 * client/connection anyway (but log an error!) if the
			 * origin is the local server. */

			if( Client != Client_ThisServer( ))
			{
				/* Invalid KILL received from remote */
				if( Client_Type( c ) == CLIENT_SERVER )
					msg = ERR_CANTKILLSERVER_MSG;
				else
					msg = ERR_NOPRIVILEGES_MSG;
				return IRC_WriteStrClient( Client, msg,
					Client_ID( Client ));
			}

			Log( LOG_ERR, "Got KILL for invalid client type: %d, \"%s\"!",
			     Client_Type( c ), Req->argv[0] );
		}

		/* Kill the client NOW:
		 *  - Close the local connection (if there is one),
		 *  - Destroy the CLIENT structure for remote clients.
		 * Note: Conn_Close() removes the CLIENT structure as well. */
		conn = Client_Conn( c );
		if(conn > NONE)
			Conn_Close(conn, NULL, reason, true);
		else
			Client_Destroy(c, NULL, reason, false);
	}
	else
		Log( LOG_NOTICE, "Client with nick \"%s\" is unknown here.", Req->argv[0] );

	/* Are we still connected or were we killed, too? */
	if(( my_conn > NONE ) && ( Conn_GetClient( my_conn )))
		return CONNECTED;
	else
		return DISCONNECTED;
} /* IRC_KILL */


/**
 * Handler for the IRC command NOTICE.
 */
GLOBAL bool
IRC_NOTICE(CLIENT *Client, REQUEST *Req)
{
	return Send_Message(Client, Req, CLIENT_USER, false);
} /* IRC_NOTICE */


/**
 * Handler for the IRC command PRIVMSG.
 */
GLOBAL bool
IRC_PRIVMSG(CLIENT *Client, REQUEST *Req)
{
	return Send_Message(Client, Req, CLIENT_USER, true);
} /* IRC_PRIVMSG */


/**
 * Handler for the IRC command SQUERY.
 */
GLOBAL bool
IRC_SQUERY(CLIENT *Client, REQUEST *Req)
{
	return Send_Message(Client, Req, CLIENT_SERVICE, true);
} /* IRC_SQUERY */


GLOBAL bool
IRC_TRACE( CLIENT *Client, REQUEST *Req )
{
	CLIENT *from, *target, *c;
	CONN_ID idx, idx2;
	char user[CLIENT_USER_LEN];

	assert( Client != NULL );
	assert( Req != NULL );

	/* Bad number of arguments? */
	if( Req->argc > 1 ) return IRC_WriteStrClient( Client, ERR_NORECIPIENT_MSG, Client_ID( Client ), Req->command );

	/* Search sender */
	if( Client_Type( Client ) == CLIENT_SERVER ) from = Client_Search( Req->prefix );
	else from = Client;
	if( ! from ) return IRC_WriteStrClient( Client, ERR_NOSUCHNICK_MSG, Client_ID( Client ), Req->prefix );

	/* Search target */
	if( Req->argc == 1 ) target = Client_Search( Req->argv[0] );
	else target = Client_ThisServer( );
	
	/* Forward command to other server? */
	if( target != Client_ThisServer( ))
	{
		if(( ! target ) || ( Client_Type( target ) != CLIENT_SERVER )) return IRC_WriteStrClient( from, ERR_NOSUCHSERVER_MSG, Client_ID( from ), Req->argv[0] );

		/* Send RPL_TRACELINK back to initiator */
		idx = Client_Conn( Client ); assert( idx > NONE );
		idx2 = Client_Conn( Client_NextHop( target )); assert( idx2 > NONE );
		if( ! IRC_WriteStrClient( from, RPL_TRACELINK_MSG, Client_ID( from ), PACKAGE_NAME, PACKAGE_VERSION, Client_ID( target ), Client_ID( Client_NextHop( target )), Option_String( idx2 ), time( NULL ) - Conn_StartTime( idx2 ), Conn_SendQ( idx ), Conn_SendQ( idx2 ))) return DISCONNECTED;

		/* Forward command */
		IRC_WriteStrClientPrefix( target, from, "TRACE %s", Req->argv[0] );
		return CONNECTED;
	}

	/* Infos about all connected servers */
	c = Client_First( );
	while( c )
	{
		if( Client_Conn( c ) > NONE )
		{
			/* Local client */
			if( Client_Type( c ) == CLIENT_SERVER )
			{
				/* Server link */
				strlcpy( user, Client_User( c ), sizeof( user ));
				if( user[0] == '~' ) strlcpy( user, "unknown", sizeof( user ));
				if( ! IRC_WriteStrClient( from, RPL_TRACESERVER_MSG, Client_ID( from ), Client_ID( c ), user, Client_Hostname( c ), Client_Mask( Client_ThisServer( )), Option_String( Client_Conn( c )))) return DISCONNECTED;
			}
			if(( Client_Type( c ) == CLIENT_USER ) && ( strchr( Client_Modes( c ), 'o' )))
			{
				/* IRC Operator */
				if( ! IRC_WriteStrClient( from, RPL_TRACEOPERATOR_MSG, Client_ID( from ), Client_ID( c ))) return DISCONNECTED;
			}
		}
		c = Client_Next( c );
	}

	IRC_SetPenalty( Client, 3 );
	return IRC_WriteStrClient( from, RPL_TRACEEND_MSG, Client_ID( from ), Conf_ServerName, PACKAGE_NAME, PACKAGE_VERSION, NGIRCd_DebugLevel );
} /* IRC_TRACE */


GLOBAL bool
IRC_HELP( CLIENT *Client, REQUEST *Req )
{
	COMMAND *cmd;

	assert( Client != NULL );
	assert( Req != NULL );

	/* Bad number of arguments? */
	if( Req->argc > 0 ) return IRC_WriteStrClient( Client, ERR_NORECIPIENT_MSG, Client_ID( Client ), Req->command );

	cmd = Parse_GetCommandStruct( );
	while( cmd->name )
	{
		if( ! IRC_WriteStrClient( Client, "NOTICE %s :%s", Client_ID( Client ), cmd->name )) return DISCONNECTED;
		cmd++;
	}
	
	IRC_SetPenalty( Client, 2 );
	return CONNECTED;
} /* IRC_HELP */


static char *
#ifdef ZLIB
Option_String(CONN_ID Idx)
#else
Option_String(UNUSED CONN_ID Idx)
#endif
{
	static char option_txt[8];
#ifdef ZLIB
	UINT16 options;

	options = Conn_Options(Idx);
#endif

	strcpy(option_txt, "F");	/* No idea what this means, but the
					 * original ircd sends it ... */
#ifdef ZLIB
	if(options & CONN_ZIP)		/* zlib compression supported. */
		strcat(option_txt, "z");
#endif

	return option_txt;
} /* Option_String */


static bool
Send_Message(CLIENT * Client, REQUEST * Req, int ForceType, bool SendErrors)
{
	CLIENT *cl, *from;
	CL2CHAN *cl2chan;
	CHANNEL *chan;
	char *currentTarget = Req->argv[0];
	char *lastCurrentTarget = NULL;
	char *message = NULL;

	assert(Client != NULL);
	assert(Req != NULL);

	if (Req->argc == 0) {
		if (!SendErrors)
			return CONNECTED;
		return IRC_WriteStrClient(Client, ERR_NORECIPIENT_MSG,
					  Client_ID(Client), Req->command);
	}
	if (Req->argc == 1) {
		if (!SendErrors)
			return CONNECTED;
		return IRC_WriteStrClient(Client, ERR_NOTEXTTOSEND_MSG,
					  Client_ID(Client));
	}
	if (Req->argc > 2) {
		if (!SendErrors)
			return CONNECTED;
		return IRC_WriteStrClient(Client, ERR_NEEDMOREPARAMS_MSG,
					  Client_ID(Client), Req->command);
	}

	if (Client_Type(Client) == CLIENT_SERVER)
		from = Client_Search(Req->prefix);
	else
		from = Client;
	if (!from)
		return IRC_WriteStrClient(Client, ERR_NOSUCHNICK_MSG,
					  Client_ID(Client), Req->prefix);

#ifdef ICONV
	if (Client_Conn(Client) > NONE)
		message = Conn_EncodingFrom(Client_Conn(Client), Req->argv[1]);
	else
#endif
		message = Req->argv[1];

	/* handle msgtarget = msgto *("," msgto) */
	currentTarget = strtok_r(currentTarget, ",", &lastCurrentTarget);
	ngt_UpperStr(Req->command);

	while (currentTarget) {
		/* Check for and handle valid <msgto> of form:
		 * RFC 2812 2.3.1:
		 *   msgto =  channel / ( user [ "%" host ] "@" servername )
		 *   msgto =/ ( user "%" host ) / targetmask
		 *   msgto =/ nickname / ( nickname "!" user "@" host )
		 */
		if (strchr(currentTarget, '!') == NULL)
			/* nickname */
			cl = Client_Search(currentTarget);
		else
			cl = NULL;

		if (cl == NULL) {
			/* If currentTarget isn't a nickname check for:
			 * user ["%" host] "@" servername
			 * user "%" host
			 * nickname "!" user "@" host
			 */
			char target[COMMAND_LEN];
			char * nick = NULL;
			char * user = NULL;
			char * host = NULL;
			char * server = NULL;

			strlcpy(target, currentTarget, COMMAND_LEN);
			server = strchr(target, '@');
			if (server) {
				*server = '\0';
				server++;
			}
			host = strchr(target, '%');
			if (host) {
				*host = '\0';
				host++;
			}
			user = strchr(target, '!');
			if (user) {
				/* msgto form: nick!user@host */
				*user = '\0';
				user++;
				nick = target;
				host = server; /* not "@server" but "@host" */
			} else {
				user = target;
			}

			for (cl = Client_First(); cl != NULL; cl = Client_Next(cl)) {
				if (Client_Type(cl) != CLIENT_USER &&
				    Client_Type(cl) != CLIENT_SERVICE)
					continue;
				if (nick != NULL && host != NULL) {
					if (strcasecmp(nick, Client_ID(cl)) == 0 &&
					    strcasecmp(user, Client_User(cl)) == 0 &&
					    strcasecmp(host, Client_HostnameDisplayed(cl)) == 0)
						break;
					else
						continue;
				}
				if (strcasecmp(user, Client_User(cl)) != 0)
					continue;
				if (host != NULL && strcasecmp(host,
						Client_HostnameDisplayed(cl)) != 0)
					continue;
				if (server != NULL && strcasecmp(server,
						Client_ID(Client_Introducer(cl))) != 0)
					continue;
				break;
			}
		}

		if (cl) {
			/* Target is a user, enforce type */
#ifndef STRICT_RFC
			if (Client_Type(cl) != ForceType &&
			    !(ForceType == CLIENT_USER &&
			      (Client_Type(cl) == CLIENT_USER ||
			       Client_Type(cl) == CLIENT_SERVICE))) {
#else
			if (Client_Type(cl) != ForceType) {
#endif
				if (SendErrors && !IRC_WriteStrClient(
				    from, ERR_NOSUCHNICK_MSG,Client_ID(from),
				    currentTarget))
					return DISCONNECTED;
				goto send_next_target;
			}

#ifndef STRICT_RFC
			if (ForceType == CLIENT_SERVICE &&
			    (Conn_Options(Client_Conn(Client_NextHop(cl)))
			     & CONN_RFC1459)) {
				/* SQUERY command but RFC 1459 link: convert
				 * request to PRIVMSG command */
				Req->command = "PRIVMSG";
			}
#endif
			if (Client_HasMode(cl, 'b') &&
			    !Client_HasMode(from, 'R') &&
			    !Client_HasMode(from, 'o') &&
			    !(Client_Type(from) == CLIENT_SERVER) &&
			    !(Client_Type(from) == CLIENT_SERVICE)) {
				if (SendErrors && !IRC_WriteStrClient(from,
						ERR_NONONREG_MSG,
						Client_ID(from), Client_ID(cl)))
					return DISCONNECTED;
				goto send_next_target;
			}

			if (Client_HasMode(cl, 'C')) {
				cl2chan = Channel_FirstChannelOf(cl);
				while (cl2chan) {
					chan = Channel_GetChannel(cl2chan);
					if (Channel_IsMemberOf(chan, from))
						break;
					cl2chan = Channel_NextChannelOf(cl, cl2chan);
				}
				if (!cl2chan) {
					if (SendErrors && !IRC_WriteStrClient(
					    from, ERR_NOTONSAMECHANNEL_MSG,
					    Client_ID(from), Client_ID(cl)))
						return DISCONNECTED;
					goto send_next_target;
				}
			}

			if (SendErrors && (Client_Type(Client) != CLIENT_SERVER)
			    && strchr(Client_Modes(cl), 'a')) {
				/* Target is away */
				if (!IRC_WriteStrClient(from, RPL_AWAY_MSG,
							Client_ID(from),
							Client_ID(cl),
							Client_Away(cl)))
					return DISCONNECTED;
			}
			if (Client_Conn(from) > NONE) {
				Conn_UpdateIdle(Client_Conn(from));
			}
			if (!IRC_WriteStrClientPrefix(cl, from, "%s %s :%s",
						      Req->command, Client_ID(cl),
						      message))
				return DISCONNECTED;
		} else if (ForceType != CLIENT_SERVICE
			   && (chan = Channel_Search(currentTarget))) {
			if (!Channel_Write(chan, from, Client, Req->command,
					   SendErrors, message))
					return DISCONNECTED;
		} else if (ForceType != CLIENT_SERVICE
			/* $#: server/target mask, RFC 2812, sec. 3.3.1 */
			   && strchr("$#", currentTarget[0])
			   && strchr(currentTarget, '.')) {
			/* targetmask */
			if (!Send_Message_Mask(from, Req->command, currentTarget,
					       message, SendErrors))
				return DISCONNECTED;
		} else {
			if (!SendErrors)
				return CONNECTED;
			if (!IRC_WriteStrClient(from, ERR_NOSUCHNICK_MSG,
						Client_ID(from), currentTarget))
				return DISCONNECTED;
		}

	send_next_target:
		currentTarget = strtok_r(NULL, ",", &lastCurrentTarget);
		if (currentTarget)
			Conn_SetPenalty(Client_Conn(Client), 1);
	}

	return CONNECTED;
} /* Send_Message */


static bool
Send_Message_Mask(CLIENT * from, char * command, char * targetMask,
		  char * message, bool SendErrors)
{
	CLIENT *cl;
	bool client_match;
	char *mask = targetMask + 1;
	const char *check_wildcards;

	cl = NULL;

	if (strchr(Client_Modes(from), 'o') == NULL) {
		if (!SendErrors)
			return true;
		return IRC_WriteStrClient(from, ERR_NOPRIVILEGES_MSG,
					  Client_ID(from));
	}

	/*
	 * RFC 2812, sec. 3.3.1 requires that targetMask have at least one
	 * dot (".") and no wildcards ("*", "?") following the last one.
	 */
	check_wildcards = strrchr(targetMask, '.');
	assert(check_wildcards != NULL);
	if (check_wildcards &&
		check_wildcards[strcspn(check_wildcards, "*?")])
	{
		if (!SendErrors)
			return true;
		return IRC_WriteStrClient(from, ERR_WILDTOPLEVEL, targetMask);
	}

	/* #: hostmask, see RFC 2812, sec. 3.3.1 */
	if (targetMask[0] == '#') {
		for (cl = Client_First(); cl != NULL; cl = Client_Next(cl)) {
			if (Client_Type(cl) != CLIENT_USER)
				continue;
			client_match = MatchCaseInsensitive(mask, Client_Hostname(cl));
			if (client_match)
				if (!IRC_WriteStrClientPrefix(cl, from, "%s %s :%s",
						command, Client_ID(cl), message))
					return false;
		}
	} else {
		assert(targetMask[0] == '$'); /* $: server mask, see RFC 2812, sec. 3.3.1 */
		for (cl = Client_First(); cl != NULL; cl = Client_Next(cl)) {
			if (Client_Type(cl) != CLIENT_USER)
				continue;
			client_match = MatchCaseInsensitive(mask,
					Client_ID(Client_Introducer(cl)));
			if (client_match)
				if (!IRC_WriteStrClientPrefix(cl, from, "%s %s :%s",
						command, Client_ID(cl), message))
					return false;
		}
	}
	return CONNECTED;
} /* Send_Message_Mask */


/* -eof- */