#!/usr/bin/php
<?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.*/

chdir(__DIR__);
require_once './common.php';

$logfile = fopen('./server.log', 'w');
$currentgroup = NULL;
$currentarticle = NULL;

function exception_handler($exception) {
	nntp_writeline(STDOUT, '');
	nntp_writeline(STDOUT, '590 Exception: '.$exception->getMessage());
	die();
}
function error_handler($errno, $errstr, $errfile, $errline) {
	nntp_writeline(STDOUT, '');
	nntp_writeline(STDOUT, '590 Error in file '.$errfile.' line '.$errline.' error '.$errno.' '.$errstr);
	die();
}
set_exception_handler('exception_handler');
set_error_handler("error_handler");

nntp_writeline(STDOUT, '200 pNewss ready');
while (TRUE) {
	$line = nntp_readline(STDIN);
	if ($line === FALSE || $line === NULL) break;
	$cmd = strtoupper(strtok($line, " \t"));
	switch ($cmd) {
		case 'CAPABILITIES':
			nntp_writeline(STDOUT, '101 Capability list:');
			nntp_writeline_data(STDOUT, 'VERSION 2');
			nntp_writeline_data(STDOUT, 'IMPLEMENTATION pNewss [http://wiki.ucis.nl/pNewss]');
			nntp_writeline_data(STDOUT, 'POST');
			nntp_writeline_data(STDOUT, 'READER');
			nntp_writeline_data(STDOUT, 'IHAVE');
			nntp_writeline_data(STDOUT, 'LIST ACTIVE');
			nntp_writeline(STDOUT, '.');
			break;
		case 'DATE':
			nntp_writeline(STDOUT, '111 '.gmdate('YmdHis'));
			break;
		case 'HELP':
			nntp_writeline(STDOUT, '100 Help text follows:');
			nntp_writeline_data(STDOUT, 'Supported commands: CAPABILITIES,DATE,HELP,LIST,GROUP,LISTGROUP,STAT,HEAD,BODY,ARTICLE,LAST,NEXT,POST,IHAVE,QUIT');
			nntp_writeline(STDOUT, '.');
			break;
		case 'LIST':
			nntp_writeline(STDOUT, '215 list of groups follows');
			foreach ($db->evalAllAssoc('SELECT * FROM `groups`') as $group) {
				$groupmessages = $db->evalRow('SELECT MIN(`number`), MAX(`number`) FROM `groupmessages` WHERE `group` = ?', $group['id']);
				nntp_writeline_data(STDOUT, $group['name'].' '.intval($groupmessages[1]).' '.intval($groupmessages[0]).' n');
			}
			nntp_writeline(STDOUT, '.');
			break;
		case 'GROUP':
		case 'LISTGROUP':
			$groupname = strtok(" \t");
			if ($groupname === FALSE) {
				$group = $currentgroup;
			} else {
				$group = $db->evalRowAssoc('SELECT * FROM `groups` WHERE `name` = ?', $groupname);
			}
			if ($group === FALSE) {
				nntp_writeline(STDOUT, '411 No such group '.$groupname);
			} else {
				$currentgroup = $group;
				$groupmessages = $db->evalRow('SELECT MIN(`number`), MAX(`number`), COUNT(`number`) FROM `groupmessages` WHERE `group` = ?', $group['id']);
				nntp_writeline(STDOUT, '211 '.intval($groupmessages[2]).' '.intval($groupmessages[0]).' '.intval($groupmessages[1]).' '.$group['name']);
				if ($groupmessages[0] === NULL) {
					$currentarticle = NULL;
				} else {
					$currentarticle = $db->evalRowAssoc('SELECT * FROM `groupmessages` WHERE `group` = ? AND `number` = ?', array($group['id'], $groupmessages[0]));
					if ($currentarticle === FALSE) $currentarticle = NULL;
				}
				if ($cmd == 'LISTGROUP') {
					$range = strtok(" \t");
					if ($range !== FALSE) {
						$parts = explode('-', $range);
						if (count($parts) == 1 || !strlen($parts[1])) {
							$query = 'SELECT `number` FROM `groupmessages` WHERE `group` = ? AND `number` >= ?';
							$queryargs = array($group['id'], $parts[0]);
						} else {
							$query = 'SELECT `number` FROM `groupmessages` WHERE `group` = ? AND `number` BETWEEN ? AND ?';
							$queryargs = array($group['id'], $parts[0], $parts[1]);
						}
					} else {
						$query = 'SELECT `number` FROM `groupmessages` WHERE `group` = ?';
						$queryargs = array($group['id']);
					}
					foreach ($db->evalColumn($query, $queryargs) as $number) nntp_writeline_data(STDOUT, $number);
					nntp_writeline(STDOUT, '.');
				}
			}
			break;
		case 'STAT':
		case 'HEAD':
		case 'BODY':
		case 'ARTICLE':
			$article = nntp_get_article(strtok(" \t"));
			if ($article === NULL) break;
			switch ($cmd) {
				case 'ARTICLE': nntp_writeline(STDOUT, '220 '.$article['messagenumber'].' <'.$article['messageid'].'> article'); break;
				case 'HEAD': nntp_writeline(STDOUT, '221 '.$article['messagenumber'].' <'.$article['messageid'].'> head'); break;
				case 'BODY': nntp_writeline(STDOUT, '222 '.$article['messagenumber'].' <'.$article['messageid'].'> body'); break;
				case 'STAT': nntp_writeline(STDOUT, '223 '.$article['messagenumber'].' <'.$article['messageid'].'> stat'); break;
				default: throw new Exception('Internal error');
			}
			if ($cmd == 'HEAD' || $cmd == 'ARTICLE') foreach (explode("\r\n", $article['header']) as $line) nntp_writeline_data(STDOUT, $line);
			if ($cmd == 'HEAD' || $cmd == 'ARTICLE') {
				$grouprefsh = array('localhost');
				foreach ($db->evalAllAssoc('SELECT * FROM `groupmessages` WHERE `message` = ?', $article['id']) as $groupref) {
					$groupname = $db->eval('SELECT `name` FROM `groups` WHERE `id` = ?', $groupref['group']);
					$grouprefsh[] = $groupname.':'.$groupref['number'];
				}
				nntp_writeline_data(STDOUT, 'Xref: '.implode(' ', $grouprefsh));
			}
			if ($cmd == 'ARTICLE') nntp_writeline_data(STDOUT, '');
			if ($cmd == 'BODY' || $cmd == 'ARTICLE') foreach (explode("\r\n", $article['body']) as $line) nntp_writeline_data(STDOUT, $line);
			if ($cmd != 'STAT') nntp_writeline(STDOUT, '.');
			break;
		case 'LAST':
		case 'NEXT':
			if ($currentarticle === NULL) {
				nntp_writeline(STDOUT, '420 no current article has been selected');
				break;
			}
			switch ($cmd) {
				case 'LAST': $query = 'SELECT * FROM `groupmessages` WHERE `group` = ? AND `number` < ? ORDER BY `number` DESC LIMIT 1'; break;
				case 'NEXT': $query = 'SELECT * FROM `groupmessages` WHERE `group` = ? AND `number` > ? ORDER BY `number` ASC LIMIT 1'; break;
				default: throw new Exception('Internal error');
			}
			$article = $db->evalRowAssoc($query, array($currentarticle['group'], $currentarticle['number']));
			if ($article === FALSE) {
				nntp_writeline(STDOUT, '422 no previous article in this group');
			} else {
				$articlea = $db->evalRowAssoc('SELECT * FROM `messages` WHERE `id` = ?', $article['message']);
				if ($articlea === FALSE) {
					nntp_writeline(STDOUT, '430 no such article found');
					return NULL;
				}
				$currentarticle = $article;
				nntp_writeline(STDOUT, '223 '.$article['number'].' <'.$articlea['messageid'].'> ok');
			}
			break;
		case 'POST':
			nntp_writeline(STDOUT, '340 Ok, recommended message-ID <'.md5(time().rand()).'@pNews.Core.UCIS.nl>');
			$lines = nntp_readlines(STDIN);
			try {
				$messageid = nntp_article_store($lines);
				nntp_writeline(STDOUT, '240 Article received <'.$messageid.'>');
			} catch (Exception $ex) {
				nntp_writeline(STDOUT, '441 '.$ex->getMessage());
			}
			break;
		case 'IHAVE':
			$messageid = strtok(" \t");
			if ($messageid === FALSE || strlen($messageid) <= 2 || $messageid[0] != '<' || $messageid[strlen($messageid)-1] == '>') {
				nntp_writeline(STDOUT, '435 Argument error');
				break;
			}
			$messageid = substr($messageid, 1, -1);
			if ($db->evalRow('SELECT `id` FROM `messages` WHERE `messageid` = ?', $messageid) !== FALSE) {
				nntp_writeline(STDOUT, '435 Duplicate');
				break;
			}
			nntp_writeline(STDOUT, '335 Send article to be transferred');
			$lines = nntp_readlines(STDIN);
			try {
				$messageid = nntp_article_store($lines);
				nntp_writeline(STDOUT, '235 Article received <'.$messageid.'>');
			} catch (Exception $ex) {
				nntp_writeline(STDOUT, '437 '.$ex->getMessage());
			}
			break;
		case 'QUIT':
			nntp_writeline(STDOUT, '205 Bye.');
			return;
		default:
			nntp_writeline(STDOUT, '500 Command not understood');
			break;
	}
}

function nntp_get_article($article) {
	global $currentgroup, $currentarticle, $db;
	if ($article === FALSE) {
		if ($currentarticle === NULL) {
			nntp_writeline(STDOUT, '420 no current article has been selected');
			return NULL;
		}
		$messagenumber = $currentarticle['number'];
		$article = $db->evalRowAssoc('SELECT * FROM `messages` WHERE `id` = ?', $currentarticle['message']);
		if ($article === FALSE) {
			nntp_writeline(STDOUT, '430 no such article found');
			return NULL;
		}
	} elseif (strlen($article) > 2 && $article[0] == '<' && $article[strlen($article)-1] == '>') {
		$messagenumber = 0;
		$article = substr($article, 1, -1);
		$article = $db->evalRowAssoc('SELECT * FROM `messages` WHERE `messageid` = ?', $article);
		if ($article === FALSE) {
			nntp_writeline(STDOUT, '430 no such article found');
			return NULL;
		}
	} elseif (is_numeric($article)) {
		if ($currentgroup === NULL) {
			nntp_writeline(STDOUT, '412 no newsgroup has been selected');
			return NULL;
		}
		$article = $db->evalRowAssoc('SELECT * FROM `groupmessages` WHERE `group` = ? AND `number` = ?', array($currentgroup['id'], $article));
		if ($article === FALSE) {
			nntp_writeline(STDOUT, '423 no such article number in this group');
			return NULL;
		}
		$currentarticle = $article;
		$messagenumber = $article['number'];
		$article = $db->evalRowAssoc('SELECT * FROM `messages` WHERE `id` = ?', $article['message']);
		if ($article === FALSE) {
			nntp_writeline(STDOUT, '430 no such article found');
			return NULL;
		}
	} else {
		nntp_writeline(STDOUT, '500 Error in arguments');
	}
	$article['messagenumber'] = $messagenumber;
	return $article;
}

function writelog($line) {
	global $logfile;
	fwrite($logfile, $line."\n");
}