<?php
/* Copyright 2010 Ivo Smits <Ivo@UCIS.nl>. All rights reserved.
   Redistribution and use in source and binary forms, with or without modification, are
   permitted provided that the following conditions are met:

   1. Redistributions of source code must retain the above copyright notice, this list of
      conditions and the following disclaimer.

   2. 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.

   THIS SOFTWARE IS PROVIDED ``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 AUTHORS 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.

   The views and conclusions contained in the software and documentation are those of the
   authors and should not be interpreted as representing official policies, either expressed
   or implied, of Ivo Smits.*/

if (defined('app_loaded')) return;
define('app_loaded', TRUE);
if (!isset($config)) include './config.php';

print("UCIS UDPMSG3 IRC server (c) 2010 Ivo Smits <Ivo@UCIS.nl>\n");
print("More information: http://wiki.ucis.nl/UDPMSG3\n");
print("\n");

srand();

class Channel {
	public $name = NULL;
	public $udpmsg = FALSE;
	public $users = array();
	public $persistent = FALSE;
	public function __construct($name) { $this->name = $name; }
}
class Client {
	public $socket = NULL;
	public $name = NULL;
	public $channels = array();
	public $readbuffer = '';
}

$channels = array();
$clients = array();
$udpmsg = NULL;
$udpmsg_config = NULL;
$udpmsg_connected = FALSE;
$udpmsg_timer = 0;
$udpmsg_buffer = '';
$udpmsg_channels = array();
$listener = NULL;

srand();

prepare();
configure();
init();
readloop();

function getchannel($name) {
	global $channels;
	if (array_key_exists($name, $channels)) return $channels[$name];
	$ch = new Channel($name);
	$channels[$name] = $ch;
	return $ch;
}
function configure() {
	global $channels, $config;
	global $udpmsg, $udpmsg_config, $udpmsg_channels;

	print("Parsing configuration...\n");
	//require 'config.php';

	if (isset($config['udpmsg'])) {
		$udpmsg_config = $config['udpmsg'];
		$udpmsg = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
		socket_set_nonblock($udpmsg);
		@socket_connect($udpmsg, $udpmsg_config['host'], $udpmsg_config['port']);
	}
	foreach ($config['channels'] as $key => $cf) {
		$ch = getchannel($key);
		$ch->persistent = TRUE;
		if (isset($cf['udpmsg'])) {
			$ch->udpmsg = $cf['udpmsg'];
			$udpmsg_channels[$cf['udpmsg']] = $ch;
		}
	}
}

function prepare() {
	global $channels;
	print("Starting IRC Relay...\n");
}

function init() {
	global $listener;
	print("Initializing...\n");
	$listener = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
	socket_bind($listener, '0.0.0.0', 7777) or die("Could not bind listening socket.\n");
	socket_listen($listener) or die("Could not start listening.\n");
}

function readloop() {
	global $channels, $clients, $udpmsg, $listener, $udpmsg_connected, $udpmsg_config, $udpmsg_timer;

	$ltime = 0;

	print("Running\n");
	while (TRUE) {
		$ntime = time();
		$tdiff = $ntime - $ltime;
		$ltime = $ntime;

		if ($udpmsg === NULL && $udpmsg_config['host'] !== NULL) {
			$udpmsg_timer += $tdiff;
			if ($udpmsg_timer >= 30) {
				fprintf(STDERR, "UDPMSG: Reconnecting...\n");
				$udpmsg = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
				socket_set_nonblock($udpmsg);
				@socket_connect($udpmsg, $udpmsg_config['host'], $udpmsg_config['port']);
				$udpmsg_timer = 0;
			}
		}

		$selread = array();
		$selwrite = array();
		$selerror = array();

		if ($udpmsg !== NULL) {
			$selread[] = $udpmsg;
			$selerror[] = $udpmsg;
			if (!$udpmsg_connected) $selwrite[] = $udpmsg;
		}
		$selread[] = $listener;

		foreach ($clients as $client) {
			$selread[] = $client->socket;
			$selerror[] = $client->socket;
		}

		socket_select(&$selread, &$selwrite, &$selerror, 10);

		if (in_array($listener, $selread)) {
			client_accept($listener);
		}

		if (in_array($udpmsg, $selerror)) {
			fprintf(STDERR, "UDPMSG: Error: select error.\n");
			socket_close($udpmsg);
			$udpmsg = NULL;
			$udpmsg_connected = FALSE;
		} else {
			if (in_array($udpmsg, $selwrite) && !$udpmsg_connected) {
				fprintf(STDERR, "UDPMSG: Connected.\n");
				$udpmsg_buffer = '';
				$udpmsg_connected = TRUE;
			}
			if (in_array($udpmsg, $selread)) {
				if (!udpmsg_read($udpmsg)) {
					fprintf(STDERR, "UDPMSG: Error: closing connection.\n");
					socket_close($udpmsg);
					$udpmsg = NULL;
					$udpmsg_connected = FALSE;
				}
			}
		}

		foreach ($clients as $client) {
			if (in_array($client->socket, $selerror)) {
				client_close($client);
			} else if (in_array($client->socket, $selread)) {
				if (!client_read($client)) {
					client_close($client);
				}
			}
		}
	}
}

function client_accept($listener) {
	global $clients;
	$client = new Client();
	$client->socket = socket_accept($listener);
	if (!$client->socket) return;
	if (!socket_getpeername($client->socket, &$addr, &$port)) $addr = 'unknown';
	fprintf(STDERR, 'Accepted client '.$addr.':'.$port."\n");
	client_send($client, ':server NOTICE AUTH :*** Not looking up your hostname, we do not care.');
	client_send($client, ':server NOTICE AUTH :*** Not checking ident, are you serious?');
	$clients[(int)($client->socket)] = $client;
}

function client_close($client, $reason = '') {
	global $clients, $channels;
	socket_close($client->socket);
	array_remove($clients, $client);
	$users = array();
	foreach ($client->channels as $ch) {
		array_remove($ch->users, $client);
		if (count($ch->users)) {
			foreach ($ch->users as $user) if (!in_array($user, $users)) $users[] = $user;
		} elseif (!$ch->persistent) {
			array_remove($channels, $ch);
		}
	}
	foreach ($users as $user) client_send($user, ':'.$client->name.' QUIT :'.$reason);
}

function udpmsg_read() {
	global $channels, $clients, $udpmsg, $udpmsg_buffer, $udpmsg_channels, $udpmsg_config;
	$msg = socket_read($udpmsg, 1024);
	if (!strlen($msg)) {
		fprintf(STDERR, "UDPMSG: End of file\n");
		return FALSE;
	}
	$udpmsg_buffer .= $msg;
	while (strlen($udpmsg_buffer) > 2) {
		$len = ord($udpmsg_buffer[0]) * 256 + ord($udpmsg_buffer[1]);
		if ($len <= 0 || $len > 1024) {
			fprintf(STDERR, "UDPMSG: Error: protocol error\n");
			return FALSE;
		}
		if (strlen($udpmsg_buffer) < 2 + $len) break;
		$msg = substr($udpmsg_buffer, 2, $len);
		$udpmsg_buffer = substr($udpmsg_buffer, 2 + $len);
		$parts = explode("\0", $msg);
		$ret = array();
		for ($i = 0; $i < count($parts)-1; $i += 2) $ret[$parts[$i]] = $parts[$i+1];

		if (!isset($ret['CHN']) || !isset($ret['CMD']) || !isset($ret['USR'])) continue;
		if (!array_key_exists($ret['CHN'], $udpmsg_channels)) continue;
		$ch = $udpmsg_channels[$ret['CHN']];
		if ($ret['CMD'] == 'MSG') {
			if (!isset($ret['MSG'])) continue;
			$from = preg_replace('/[^a-zA-Z0-9\-_]/', '', $ret['USR']);
			if ($udpmsg_config['nicknetwork'] && isset($ret['NET'])) $from = preg_replace('/[^a-zA-Z0-9\-_]/', '', $ret['NET']).$udpmsg_config['nickseparator'].$from;
			$from = $udpmsg_config['nickprefix'].$from;
			$message = preg_replace('/[\x00\x10-\x13]/', '', $ret['MSG']);
			channel_send($ch, NULL, ':'.$from.' PRIVMSG '.$ch->name.' :'.$message);
		}
	}
	return TRUE;
}

function udpmsg_send($arr) {
	global $udpmsg, $udpmsg_connected;
	if (!$udpmsg || !$udpmsg_connected) return;
	$tmp = array();
	foreach ($arr as $key => $value) { $tmp[] = $key; $tmp[] = $value; }
	$tmp[] = '';
	$msg = implode("\0", $tmp);
	$len = strlen($msg);
	if ($len > 1024) {
		fprintf(STDERR, "UDPMSG: Error: message too long!\n");
		return;
	}
	$lens = chr(floor($len / 256)).chr($len % 256);
	socket_write($udpmsg, $lens.$msg);
}


function array_remove(&$arr, $item) {
	foreach ($arr as $key => $value) if ($value === $item) unset($arr[$key]);
}

function find_nick($nick) {
	global $clients;
	$nick = strtoupper($nick);
	foreach ($clients as $client) if (strtoupper($client->name) == $nick) return $client;
	return FALSE;
}

function client_read($client) {
	$newdata = socket_read($client->socket, 1024);
	if ($newdata === FALSE || !strlen($newdata)) return FALSE;
	$client->readbuffer .= $newdata;
	$offset = 0;
	$len = strlen($client->readbuffer);
	while ($offset < $len) {
		$posa = strpos($client->readbuffer, "\n", $offset);
		$posb = strpos($client->readbuffer, "\r", $offset);
		if ($posa !== FALSE && $posb !== FALSE) {
			$pos = min($posa, $posb);
		} else if ($posa !== FALSE) {
			$pos = $posa;
		} else if ($posb !== FALSE) {
			$pos = $posb;
		} else {
			break;
		}
		$line = substr($client->readbuffer, $offset, $pos - $offset);
		if (strlen($line)) {
			if (!client_process($client, $line)) return FALSE;
		}
		$offset = $pos + 1;
	}
	if ($offset == $len) {
		$client->readbuffer = '';
	} else if ($offset != 0) {
		$client->readbuffer = substr($client->readbuffer, $offset);
	}
	return TRUE;
}

function client_process($client, $line) {
	$partsa = explode(' :', $line, 2);
	$parts = explode(' ', $partsa[0]);
	$command = array_shift(&$parts);
	if (count($partsa) > 1) array_push(&$parts, $partsa[1]);
	$clientname = $client->name;
	switch (strtoupper($command)) {
		case 'NICK': //Nickname change: newnick = $parts[0]
			if (find_nick($parts[0])) {
				client_sendnumeric($client, 433, $parts[0].' :Nickname in use');
			} elseif (!preg_match('/^[a-zA-Z0-9\-_]+$/', $parts[0])) {
				client_sendnumeric($client, 432, $parts[0].' :Erroneous nickname');
			} elseif ($client->name === NULL) {
				$client->name = $parts[0];
				client_sendnumeric($client, 001, ':Welcome to the Internet Relay Chat Network');
				client_sendnumeric($client, 002, ':Your host is UDPMSG3-IRCD');
				client_sendnumeric($client, 003, ':This server was created some time ago');
				client_sendnumeric($client, 004, 'irc.udpmsg3.local 1.0 + +');
				client_sendnumeric($client, 005, 'NICKLEN=16 CHANNELLEN=16 CHANTYPES=# NETWORK=UDPMSG3 :are supported by this server');
				client_sendnumeric($client, 251, ':There are '.count($GLOBALS['clients']).' users and some invisible on a bunch of servers');
				client_sendnumeric($client, 252, '0 :operator(s) online');
				client_sendnumeric($client, 254, count($GLOBALS['channels']).' :channels formed');
				client_sendnumeric($client, 255, ':I have a bunch of clients and a bunch of servers');
				client_sendnumeric($client, 265, ':Current Local Users: undisclosed');
				client_sendnumeric($client, 266, ':Current Global Users: unknown');
				client_sendnumeric($client, 375, ':- server Message of the Day - ');
				client_sendnumeric($client, 372, ':- No message, sorry.');
				client_sendnumeric($client, 376, ':End of /MOTD command.');
			} else {
				$users = array($client);
				foreach ($client->channels as $ch) foreach ($ch->users as $user) if (!in_array($user, $users)) $users[] = $user;
				foreach ($users as $user) client_send($user, ':'.$client->name.' NICK :'.$parts[0]);
				$client->name = $parts[0];
			}
			break;
		case 'USER':
		case 'PASS':
			break;
		default:
			if ($client->name === NULL) {
				client_send($client, ':server 451 '.$command.' :You have not registered');
				break;
			}
			switch (strtoupper($command)) {
				case 'PING':
					client_send($client, 'PONG :'.$parts[0]);
					break;
				case 'PRIVMSG':
				case 'NOTICE':
					$channels = explode(',', $parts[0]);
					foreach ($channels as $chn) {
						if ($chn[0] == '#') {
							if (!array_key_exists($chn, $client->channels))  {
								client_sendnumeric($client, 404, $chn.' :Can not send to channel');
							} else {
								channel_sendmsg($client->channels[$chn], $client, $parts[1]);
							}
						} else {
							if ($ch = find_nick($chn)) {
								client_send($ch, ':'.$client->name.' PRIVMSG '.$chn.' :'.$parts[1]);
							} else {
								client_sendnumeric($client, 401, $chn.' :No such nickname');
							}
						}
					}
					break;
				case 'JOIN':
					$channels = explode(',', $parts[0]);
					foreach ($channels as $chn) {
						if (!preg_match('/^#[a-zA-Z0-9\-_]+$/', $chn)) {
							client_sendnumeric($client, 403, $chn.' :No such channel');
							continue;
						}
						$ch = getchannel($chn);
						if (!isset($client->channels[$chn])) {
							$client->channels[$chn] = $ch;
							$ch->users[] = $client;
							print('JOIN '.$ch->name.': '.$client->name."\n");
							channel_send($ch, NULL, ':'.$client->name.'!user@host JOIN :'.$ch->name);
						}
						client_sendnames($ch, $client);
					}
					break;
				case 'PART':
					$channels = explode(',', $parts[0]);
					foreach ($channels as $chn) {
						if (!isset($client->channels[$chn])) continue;
						$ch = $client->channels[$chn];
						print('PART '.$ch->name.': '.$client->name."\n");
						channel_send($ch, NULL, ':'.$client->name.' PART :'.$ch->name);
						unset($client->channels[$chn]);
						array_remove(&$ch->users, $client);
						if (!count($ch->users) && !$ch->persistent) array_remove($GLOBALS['channels'], $ch);
					}
					break;
				case 'QUIT':
					client_close($client, isset($parts[0]) ? 'Quit: '.$parts[0] : 'Quit');
					break;
				case 'NAMES':
					$channels = explode(',', $parts[0]);
					foreach ($channels as $chn) {
						if (!isset($client->channels[$chn])) {
							client_sendnumeric($client, 403, $chn.' :No such channel');
						} else {
							client_sendnames($client->channels[$chn], $client);
						}
					}
					break;
				case 'LIST':
					client_sendnumeric($client, 321, 'Channel :Users  Name');
					foreach ($GLOBALS['channels'] as $ch) {
						client_sendnumeric($client, 322, $ch->name.' '.count($ch->users).' :');
					}
					client_sendnumeric($client, 323, 'End of /LIST');
					break;
				case 'MODE':
				case 'USER':
				case 'USERHOST':
					break;
				default:
					client_sendnumeric($client, 421, $command.' :Unknown command');
			}
	}
	return TRUE;
}

function client_sendnames($ch, $client) {
	$nicks = array();
	foreach ($ch->users as $u) if ($u->name !== NULL) $nicks[] = $u->name;
	client_sendnumeric($client, 353, '= '.$ch->name.' :'.implode(' ', $nicks));
	client_sendnumeric($client, 366, $ch->name.' :End of /NAMES list.');
}

function client_sendnumeric($client, $num, $line) {
	client_send($client, ':server '.str_pad($num, 3, '0', STR_PAD_LEFT).' '.$client->name.' '.$line);
}

function client_send($client, $line) {
	print('W: '.$line."\n");
	$line .= "\r\n";
	socket_send($client->socket, $line, strlen($line), 0);
}

function channel_sendmsg($ch, $sender, $msg) {
	global $udpmsg_config;
	print('MESSAGE '.$ch->name.' <'.$sender->name.'> '.$msg."\n");
	channel_send($ch, $sender, ':'.$sender->name.' PRIVMSG '.$ch->name.' :'.$msg);
	if (!$ch->udpmsg) return;
	$umsg = array('CMD' => 'MSG', 'CHN' => $ch->udpmsg, 'MSG' => $msg, 'USR' => $sender->name, 'DUMMY' => rand(10000, 99999));
	if ($udpmsg_config['netname']) $umsg['NET'] = $udpmsg_config['netname'];
	udpmsg_send($umsg);
}

function channel_send($ch, $sender, $msg) {
	foreach ($ch->users as $client) {
		if ($client === $sender) continue;
		client_send($client, $msg);
	}
}