Peter M. Groen / knowledgetree

<?php

/**
 * $Id:$
 *
 * KnowledgeTree Community Edition
 * Document Management Made Simple
 * Copyright (C) 2008 KnowledgeTree Inc.
 * Portions copyright The Jam Warehouse Software (Pty) Limited
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 3 as published by the
 * Free Software Foundation.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 *
 * You can contact KnowledgeTree Inc., PO Box 7775 #87847, San Francisco,
 * California 94120-7775, or email info@knowledgetree.com.
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU General Public License version 3.
 *
 * In accordance with Section 7(b) of the GNU General Public License version 3,
 * these Appropriate Legal Notices must retain the display of the "Powered by
 * KnowledgeTree" logo and retain the original copyright notice. If the display of the
 * logo is not reasonably feasible for technical reasons, the Appropriate Legal Notices
 * must display the words "Powered by KnowledgeTree" and retain the original
 * copyright notice.
 * Contributor( s): ______________________________________
 *
 */

define('SEARCH2_INDEXER_DIR',realpath(dirname(__FILE__)) . '/');
require_once('indexing/extractorCore.inc.php');
require_once(KT_DIR . '/plugins/ktcore/scheduler/schedulerUtil.php');
require_once(KT_DIR . '/ktapi/ktapi.inc.php');

class IndexerInconsistencyException extends Exception {};

// TODO: Query Result Items code should be moved into the Search section. It has less to do with indexing...

class QueryResultItem
{
    protected $id;
	protected $title;
	protected $rank;
	protected $text;
	protected $fullpath;

	public function __construct($id, $title, $rank, $text, $fullpath)
	{
	    $this->id = $id;
	    $this->title = $title;
	    $this->rank = $rank;
	    $this->text = $text;
	    $this->fullpath = $fullpath;
	}

    public function getId() { return $this->id; }
    public function getRealId() { return $this->id; }

    public function getIsProxy() { return $this instanceof ProxyResultItem; }
    public function getIsFolder() { return substr(get_class($this), 0, 6) == 'Folder' ; }
    public function getIsDocument() { return substr(get_class($this), 0, 8) == 'Document' ; }

	public function setRank($value)
	{
	   $this->rank = number_format($value,2,'.',',');
	}

	public function getIsLive()
	{
	    return true;
	}

	public function setTitle($value)
	{
	    $this->title = $value;
	}

	public function setText($value)
	{
	    $this->text = $value;
	}

	public function getRelevance() { return (float) $this->rank; }
	public function getRank() { return $this->getRelevance(); }
	public function getText() { return (string) $this->text; }
	public function getTitle() { return (string) $this->title; }
	public function getFullPath() { return (string)  $this->fullpath; }

	protected function __get($property)
	{
        if (empty($property))
        {
            return '';
        }

        $method = 'get' . $property;
        if (method_exists($this, $method))
        {
            return $this->$method();
        }
        return $this->getUnknown();
	}

	protected function getUnknown()
	{
	    return _kt('n/a');
	}

	protected function __set($property, $value)
	{
	    if (empty($property))
        {
            return '';
        }

        $method = 'set' . $property;
        if (method_exists($this, $method))
        {
            return $this->$method($value);
        }
        throw new Exception("Unknown property '$property' to set on QueryResultItem");
	}
}

class ProxyResultItem extends QueryResultItem
{
    protected $proxy;
    protected $proxyId;

    public function __construct($proxyId, $proxy)
    {
        parent::__construct($proxyId, $proxy->getTitle, $proxy->getRank(), $proxy->getText(), $proxy->getFullPath());
        $this->proxyId = $proxyId;
        $this->proxy = $proxy;
    }

    public function getId() { return $this->proxyId; }
    public function getTitle() { return $this->proxy->getTitle(); }
    public function getRealId() { return $this->proxy->getId(); }

	protected function __get($property)
	{
        $method = 'get' . $property;

        if (method_exists($this, $method))
        {
            return $this->$method();
        }
        else
        {
            return $this->proxy->$method();
        }
	}

	protected function __set($property, $value)
	{
        $method = 'set' . $property;
        if (method_exists($this, $method))
        {
            return $this->$method($value);
        }
        else
        {
            return $this->proxy->$method($value);
        }
	}
}

class DocumentResultItem extends QueryResultItem
{
	protected $filesize;
	protected $live;
	protected $version;
	protected $mimeType;
	protected $filename;
	protected $thumbnail; // TODO: if not null, gui can display a thumbnail
	protected $viewer; // TODO: if not null, a viewer can be used to view the document
	protected $document;
	protected $checkedOutUser;
	protected $dateCheckedout;
	protected $workflowState;
	protected $workflow;
	protected $modifiedBy;
	protected $dateModified;
	protected $createdBy;
	protected $dateCreated;
	protected $owner;
	protected $immutable;
	protected $deleted;
	protected $status;
	protected $folderId;
	protected $storagePath;
	protected $documentType;
	protected $mimeIconPath;
	protected $mimeDisplay;
	protected $oemDocumentNo;

	public function __construct($document_id, $rank=null, $title=null, $text=null, $fullpath = null)
	{
	    parent::__construct($document_id, $title, $rank, $text, $fullpath);
		$this->live = true;
		$this->loadDocumentInfo();
	}

	// TODO: this is bad. must refactor to do the query on the group of documents.
	public function loadDocumentInfo()
	{
		global $default;
		$sql = "SELECT
					d.folder_id, f.full_path, f.name, dcv.size as filesize, dcv.major_version,
					dcv.minor_version, dcv.filename, cou.name as checkoutuser, w.human_name as workflow, ws.human_name as workflowstate,
					mt.mimetypes as mimetype, md.mime_doc as mimedoc, d.checkedout, mbu.name as modifiedbyuser, d.modified,
					cbu.name as createdbyuser, ou.name as owneruser, d.immutable, d.status_id, d.created,dcv.storage_path, dtl.name as document_type,
					mt.icon_path as mime_icon_path, mt.friendly_name as mime_display, d.oem_no, dmv.name as title
				FROM
					documents d
					INNER JOIN document_metadata_version dmv ON d.metadata_version_id = dmv.id
					INNER JOIN document_content_version dcv ON dmv.content_version_id = dcv.id
					INNER JOIN mime_types mt ON dcv.mime_id=mt.id
					LEFT JOIN document_types_lookup dtl ON dtl.id=dmv.document_type_id
					LEFT JOIN folders f ON f.id=d.folder_id
					LEFT JOIN users cou ON d.checked_out_user_id=cou.id
					LEFT JOIN workflows w ON dmv.workflow_id=w.id
					LEFT JOIN workflow_states ws ON dmv.workflow_state_id = ws.id
					LEFT JOIN mime_documents md ON mt.mime_document_id = md.id
					LEFT JOIN users mbu ON d.modified_user_id=mbu.id
					LEFT JOIN users cbu ON d.creator_id=cbu.id
					LEFT JOIN users ou ON d.owner_id=ou.id
				WHERE
					d.id=$this->id";

		$result = DBUtil::getOneResult($sql);

		if (PEAR::isError($result) || empty($result))
		{
			$this->live = false;
			if (PEAR::isError($result))
			{
				throw new Exception('Database exception! There appears to be an error in the system: ' .$result->getMessage());
			}

			$default->log->error('QueryResultItem: $result is null');
			$msg = 'The database did not have a record matching the result from the document indexer. This may occur if there is an inconsistency between the document indexer and the repository. The indexer needs to be repaired.';
			$default->log->error('QueryResultItem: ' . $msg);
			// TODO: repair process where we scan documents in index, and delete those for which there is nothing in the repository
			throw new IndexerInconsistencyException(_kt($msg));
		}

		// document_id, relevance, text, title

		$this->documentType = $result['document_type'];
		$this->filename=$result['filename'];
		$this->filesize = KTUtil::filesizeToString($result['filesize']);
		$this->folderId = $result['folder_id'];
		$this->title = $result['title'];

		$this->createdBy = $result['createdbyuser'];
		$this->dateCreated = $result['created'];

		$this->modifiedBy = $result['modifiedbyuser'];
		$this->dateModified = $result['modified'];

		$this->checkedOutUser = $result['checkoutuser'];
		$this->dateCheckedout = $result['checkedout'];

		$this->owner = $result['owneruser'];

		$this->version = $result['major_version'] . '.' . $result['minor_version'];

		$this->immutable = ($result['immutable'] + 0)?_kt('Immutable'):'';

		$this->workflow = $result['workflow'];
		$this->workflowState = $result['workflowstate'];

		$this->oemDocumentNo = $result['oem_no'];
		if (empty($this->oemDocumentNo)) $this->oemDocumentNo = 'n/a';

		if (is_null($result['name']))
		{
			$this->fullpath = '(orphaned)';
		}
		else
		{
			$this->fullpath = $result['full_path'];
		}

		$this->mimeType = $result['mimetype'];
		$this->mimeIconPath = $result['mime_icon_path'];
		if (empty($this->mimeIconPath))
		{
		    $this->mimeIconPath = 'unspecified_type';
		}
		$this->mimeDisplay = $result['mime_display'];

		$this->storagePath = $result['storage_path'];
		$this->status = Document::getStatusString($result['status_id']);
	}

    public function getDocumentID() { return $this->getId(); }
	public function getIsLive() { return (bool) $this->live; }
	public function getFilesize() { return $this->filesize; }
	public function getVersion() { return (string) $this->version; }
	public function getFilename() { return (string)$this->filename; }
	public function getFolderId() { return (int)$this->folderId; }
	public function getOemDocumentNo() { return (string) $this->oemDocumentNo; }
	public function getDocument() { return Document::get($this->id); }
	public function getIsAvailable() { return $this->Document->isLive(); }
	public function getCheckedOutUser() { return (string) $this->checkedOutUser; }
	public function getCheckedOutByr() { return $this->getCheckedOutUser(); }
	public function getWorkflowOnly() { return (string)$this->workflow; }
	public function getWorkflow() { return $this->getWorkflow(); }
	public function getWorkflowStateOnly() { return (string)$this->workflowState; }
	public function getWorkflowState() { return $this->getWorkflowStateOnly(); }
	public function getWorkflowAndState() {
	    if (is_null($this->workflow))
	    {
	        return '';
	    }
	    return "$this->workflow - $this->workflowState";
	}
	public function getMimeType() { return (string) $this->mimeType; }
	public function getMimeIconPath() { return (string) $this->mimeIconPath; }
	public function getMimeDisplay() { return (string) $this->mimeDisplay; }
	public function getDateCheckedOut() { return (string) $this->dateCheckedout; }
	public function getModifiedBy() { return (string) $this->modifiedBy; }
	public function getDateModified() { return (string) $this->dateModified; }
	public function getCreatedBy() { return (string) $this->createdBy; }
	public function getDateCreated() { return (string) $this->dateCreated; }
	public function getOwner() { return (string) $this->owner; }
	public function getOwnedBy() { return $this->getOwner(); }
	public function getIsImmutable() { return (bool) $this->immutable; }
	public function getImmutable() { return $this->getIsImmutable(); }
	public function getStatus() { return $this->status; }
	public function getStoragePath() { return $this->storagePath; }
	public function getDocumentType() { return $this->documentType; }
	public function getPermissions() { return KTAPI_Document::get_permission_string($this->Document); }
	public function getCanBeReadByUser() {
	    if (!$this->live)
	       return false;
	    if (Permission::userHasDocumentReadPermission($this->Document))
	       return true;
	    if (Permission::adminIsInAdminMode())
	       return true;
	    return false;
	}
}

class FolderResultItem extends QueryResultItem
{
	protected $folder;
	protected $createdBy;
	protected $parentId;

	public function __construct($folder_id, $rank=null, $title=null, $text=null, $fullpath = null)
	{
	    parent::__construct($folder_id, $title, $rank, $text, $fullpath);
		$this->loadFolderInfo();
	}

    public function getFolderID() { return $this->getId(); }
    public function getParentID() { return $this->parentId; }
    public function getCreatedBy() { return $this->createdBy; }
    public function getMimeIconPath() { return 'folder'; }
	public function getFolder() { return Folder::get($this->getFolderID()); }
    public function getPermissions() { return KTAPI_Folder::get_permission_string($this->Folder); }

    public function loadFolderInfo()
	{
		global $default;
		$folder = $this->getFolder();
		if (PEAR::isError($folder))
		{
		    throw new Exception('Database exception! There appears to be an error in the system: ' .$result->getMessage());
		}
		$this->title = $folder->getName();
		$this->fullpath = '/' . $folder->getFullPath();
		$this->parentId = $folder->getParentId();

		$user = User::get($folder->getCreatorID());
		$this->createdBy = (PEAR::isError($user))?_kt('Unknown'):$user->getName();
	}

}

class DocumentShortcutResultItem extends ProxyResultItem
{
    public function getDocumentID() { return $this->getId(); }
    public function getMimeIconPath() { return $this->proxy->getMimeIconPath() . '_shortcut'; }

}

class FolderShortcutResultItem extends ProxyResultItem
{
    public function getFolderID() { return $this->getId(); }
    public function getMimeIconPath() { return 'folder_shortcut'; }

}

function MatchResultCompare($a, $b)
{
    if ($a->Rank == $b->Rank) {
        return 0;
    }
    return ($a->Rank < $b->Rank) ? -1 : 1;
}

abstract class Indexer
{
	/**
	 * Cache of extractors
	 *
	 * @var array
	 */
	private $extractorCache;

	/**
	 * Indicates if the indexer will do logging.
	 *
	 * @var boolean
	 */
	private $debug;
	/**
	 * Cache on mime related hooks
	 *
	 * @var unknown_type
	 */
	private $mimeHookCache;
	/**
	 * Cache on general hooks.
	 *
	 * @var array
	 */
	private $generalHookCache;

	/**
	 * This is a path to the extractors.
	 *
	 * @var string
	 */
	private $extractorPath;
	/**
	 * This is a path to the hooks.
	 *
	 * @var string
	 */
	private $hookPath;

	private $enabledExtractors;

	/**
	 * Initialise the indexer
	 *
	 */
	protected function __construct()
	{
		$config = KTConfig::getSingleton();

		$this->extractorCache	= array();
		$this->debug 			= $config->get('indexer/debug', true);
		$this->hookCache 		= array();
		$this->generalHookCache = array();
		$this->extractorPath 	= $config->get('indexer/extractorPath', 'extractors');
		$this->hookPath 		= $config->get('indexer/extractorHookPath','extractorHooks');

		$this->loadExtractorStatus();
	}

	/**
	 * Get the list if enabled extractors
	 *
	 */
	private function loadExtractorStatus()
	{
		$sql = "SELECT id, name FROM mime_extractors WHERE active=1";
		$rs = DBUtil::getResultArray($sql);
		$this->enabledExtractors = array();
		foreach($rs as $item)
		{
			$this->enabledExtractors[] = $item['name'];
		}
	}

	private function isExtractorEnabled($extractor)
	{
		return in_array($extractor, $this->enabledExtractors);
	}

	/**
	 * Returns a reference to the main class
	 *
	 * @return Indexer
	 */
	public static function get()
	{
		static $singleton = null;

		if (is_null($singleton))
		{
			$config = KTConfig::getSingleton();
			$classname = $config->get('indexer/coreClass');

			require_once('indexing/indexers/' . $classname . '.inc.php');

			if (!class_exists($classname))
			{
				throw new Exception("Class '$classname' does not exist.");
			}

			$singleton = new $classname;
		}

		return $singleton;
	}

	public abstract function deleteDocument($docid);

	/**
	 * Remove the association of all extractors to mime types on the database.
	 *
	 */
	public function clearExtractors()
	{
		global $default;

		$sql = "update mime_types set extractor_id=null";
		DBUtil::runQuery($sql);

		$sql = "delete from mime_extractors";
		DBUtil::runQuery($sql);

		if ($this->debug) $default->log->debug('clearExtractors');
	}

	/**
	 * lookup the name of the extractor class based on the mime type.
	 *
	 * @param string $type
	 * @return string
	 */
	public static function resolveExtractor($type)
	{
		global $default;
		$sql = "select extractor from mime_types where filetypes='$type'";
		$class = DBUtil::getOneResultKey($sql,'extractor');
		if (PEAR::isError($class))
		{
			$default->log->error("resolveExtractor: cannot resolve $type");
			return $class;
		}
		if ($this->debug) $default->log->debug(sprintf(_kt("resolveExtractor: Resolved '%s' from mime type '%s'."), $class, $type));
		return $class;
	}

	/**
	 * Return all the discussion text.
	 *
	 * @param int $docid
	 * @return string
	 */
	public static function getDiscussionText($docid)
	{
		$sql = "SELECT
					dc.subject, dc.body
				FROM
					discussion_threads dt
					INNER JOIN discussion_comments dc ON dc.thread_id=dt.id AND dc.id BETWEEN dt.first_comment_id AND dt.last_comment_id
				WHERE
					dt.document_id=$docid";
		$result = DBUtil::getResultArray($sql);
		$text = '';

		foreach($result as $record)
		{
			$text .= $record['subject'] . "\n" . $record['body'] . "\n";
		}

		return $text;
	}

	/**
	 * Schedule the indexing of a document.
	 *
	 * @param string $document
	 * @param string $what
	 */
    public static function index($document, $what='A')
    {
    	global $default;

    	if (is_numeric($document))
    	{
    		$document = Document::get($document+0);
    	}

    	if (PEAR::isError($document))
    	{
    		$default->log->error("index: Could not index document: " .$document->getMessage());
    		return;
    	}

        $document_id = $document->getId();
        $userid=$_SESSION['userID'];
        if (empty($userid)) $userid=1;

        // we dequeue the document so that there are no issues when enqueuing
        Indexer::unqueueDocument($document_id);

        // enqueue item
        $sql = "INSERT INTO index_files(document_id, user_id, what) VALUES($document_id, $userid, '$what')";
        DBUtil::runQuery($sql);

        $default->log->debug("index: Queuing indexing of $document_id");

    }

    private static function incrementCount()
    {
        // Get count from system settings
        $count = Indexer::getIndexedDocumentCount();
        $count = (int)$count + 1;
        Indexer::updateIndexedDocumentCount($count);
    }

    public static function getIndexedDocumentCount()
    {
        $count = KTUtil::getSystemSetting('indexedDocumentCount', 0);
        return (int) $count;
    }

    public static function updateIndexedDocumentCount($cnt = 0)
    {
        KTUtil::setSystemSetting('indexedDocumentCount', $cnt);
    }

	public static function reindexQueue()
	{
		$sql = "UPDATE index_files SET processdate = null";
		DBUtil::runQuery($sql);
	}

	public static function reindexDocument($documentId)
	{
		$sql = "UPDATE index_files SET processdate=null, status_msg=null WHERE document_id=$documentId";
		DBUtil::runQuery($sql);
	}



    public static function indexAll()
    {
    	 $userid=$_SESSION['userID'];
    	 if (empty($userid)) $userid=1;

    	$sql = "DELETE FROM index_files";
    	DBUtil::runQuery($sql);

    	$sql = "INSERT INTO index_files(document_id, user_id, what) SELECT id, $userid, 'A' FROM documents WHERE status_id=1 and id not in (select document_id from index_files)";
    	DBUtil::runQuery($sql);
    }

    public static function indexFolder($folder)
    {
        $userid=$_SESSION['userID'];
    	if (empty($userid)) $userid=1;

        if (!$folder instanceof Folder && !$folder instanceof FolderProxy)
        {
            throw new Exception('Folder expected');
        }

        $full_path = $folder->getFullPath();

    	$sql = "INSERT INTO index_files(document_id, user_id, what) SELECT id, $userid, 'A' FROM documents WHERE full_path like '{$full_path}/%' AND status_id=1 and id not in (select document_id from index_files)";
    	DBUtil::runQuery($sql);
    }

    /**
     * Clearout the scheduling of documents that no longer exist.
     *
     */
    public static function clearoutDeleted()
    {
    	global $default;

        $sql = 'DELETE FROM
					index_files
				WHERE
					document_id in (SELECT d.id FROM documents AS d WHERE d.status_id=3) OR
					NOT EXISTS(SELECT index_files.document_id FROM documents WHERE index_files.document_id=documents.id)';
        DBUtil::runQuery($sql);

        $default->log->debug("Indexer::clearoutDeleted: removed documents from indexing queue that have been deleted");
    }


    /**
     * Check if a document is scheduled to be indexed
     *
     * @param mixed $document This may be a document or document id
     * @return boolean
     */
    public static function isDocumentScheduled($document)
    {
    	if (is_numeric($document))
    	{
    		$docid = $document;
    	}
    	else if ($document instanceof Document)
    	{
    		$docid = $document->getId();
    	}
    	else
    	{
    		return false;
    	}
    	$sql = "SELECT 1 FROM index_files WHERE document_id=$docid";
    	$result = DBUtil::getResultArray($sql);
    	return count($result) > 0;
    }

    /**
     * Filters text removing redundant characters such as continuous newlines and spaces.
     *
     * @param string $filename
     */
    private function filterText($filename)
    {
    	$content = file_get_contents($filename);

    	$src = array("([\r\n])","([\n][\n])","([\n])","([\t])",'([ ][ ])');
    	$tgt = array("\n","\n",' ',' ',' ');

    	// shrink what is being stored.
    	do
    	{
    		$orig = $content;
    		$content = preg_replace($src, $tgt, $content);
    	} while ($content != $orig);

    	return file_put_contents($filename, $content) !== false;
    }

    /**
     * Load hooks for text extraction process.
     *
     */
    private function loadExtractorHooks()
    {
    	$this->generalHookCache = array();
    	$this->mimeHookCache = array();


		$dir = opendir(SearchHelper::correctPath($this->hookPath));
		while (($file = readdir($dir)) !== false)
		{
			if (substr($file,-12) == 'Hook.inc.php')
			{
				require_once($this->hookPath . '/' . $file);
				$class = substr($file, 0, -8);

				if (!class_exists($class))
				{
					continue;
				}

				$hook = new $class;
				if (!($class instanceof ExtractorHook))
				{
					continue;
				}

				$mimeTypes = $hook->registerMimeTypes();
				if (is_null($mimeTypes))
				{
					$this->generalHookCache[] = & $hook;
				}
				else
				{
					foreach($mimeTypes as $type)
					{
						$this->mimeHookCache[$type][] = & $hook;
					}
				}

			}
        }
        closedir($dir);
    }

    /**
     * This is a refactored function to execute the hooks.
     *
     * @param DocumentExtractor $extractor
     * @param string $phase
     * @param string $mimeType Optional. If set, indicates which hooks must be used, else assume general.
     */
    private function executeHook($extractor, $phase, $mimeType = null)
    {
    	$hooks = array();
		if (is_null($mimeType))
		{
			$hooks = $this->generalHookCache;
		}
		else
		{
			if (array_key_exists($mimeType, $this->mimeHookCache))
			{
				$hooks = $this->mimeHookCache[$mimeType];
			}
		}
		if (empty($hooks))
		{
			return;
		}

		foreach($hooks as $hook)
		{
			$hook->$phase($extractor);
		}
    }

    private function doesDiagnosticsPass($simple=false)
    {
		global $default;

    	$config =& KTConfig::getSingleton();
		// create a index log lock file in case there are errors, and we don't need to log them forever!
    	// this function will create the lockfile if an error is detected. It will be removed as soon
    	// as the problems with the indexer are removed.
    	$lockFile = $config->get('cache/cacheDirectory') . '/index.log.lock';

    	$diagnosis = $this->diagnose();
    	if (!is_null($diagnosis))
    	{
			if (!is_file($lockFile))
			{
				$default->log->error(_kt('Indexer problem: ') . $diagnosis);
			}
			touch($lockFile);
    		return false;
    	}

    	if ($simple)
    	{
    		return true;
    	}

    	$diagnosis = $this->diagnoseExtractors();
    	if (!empty($diagnosis))
    	{
    		if (!is_file($lockFile))
			{
	    		foreach($diagnosis as $diag)
	    		{
    				$default->log->error(sprintf(_kt('%s problem: %s'), $diag['name'],$diag['diagnosis']));
    			}
			}
			touch($lockFile);
    		return false;
    	}

    	if (is_file($lockFile))
    	{
    		$default->log->info(_kt('Issues with the indexer have been resolved!'));
    		unlink($lockFile);
    	}

    	return true;
    }

    /**
     * This does the initial mime type association between mime types and text extractors
     *
     */
    public function checkForRegisteredTypes()
    {
    	global $default;

    	// we are only doing this once!
    	$initRegistered = KTUtil::getSystemSetting('mimeTypesRegistered', false);
    	if ($initRegistered)
    	{
    		return;
    	}
    	if ($this->debug) $default->log->debug('checkForRegisteredTypes: start');

    	$date = date('Y-m-d H:i');
    	$sql = "UPDATE scheduler_tasks SET run_time='$date'";
    	DBUtil::runQuery($sql);

    	$this->registerTypes(true);

    	$disable = array(
    		'windows'=>array('PSExtractor'),
    		'unix' => array()
    	);

    	$disableForOS = OS_WINDOWS?$disable['windows']:$disable['unix'];

    	if (!empty($disableForOS))
    	{
    	   $disableForOS = '\'' . implode("','", $disableForOS) .'\'';

    		$sql = "UPDATE mime_extractors SET active=0 WHERE name in ($disableForOS)";
    		DBUtil::runQuery($sql);
    		$default->log->info("checkForRegisteredTypes: disabled '$extractor'");
    	}
        $this->loadExtractorStatus();

    	if ($this->debug) $default->log->debug('checkForRegisteredTypes: done');
    	KTUtil::setSystemSetting('mimeTypesRegistered', true);
    }

    private function updatePendingDocumentStatus($documentId, $message, $level)
    {
    	$this->indexingHistory .=  "\n" . $level . ': ' . $message;
    	$message = sanitizeForSQL($this->indexingHistory);
    	$sql = "UPDATE index_files SET status_msg='$message' WHERE document_id=$documentId";
    	DBUtil::runQuery($sql);
    }

    private $restartCurrentBatch = false;

    public function restartBatch()
    {
        $this->restartCurrentBatch = true;
    }

     /**
     *
     * @param int $documentId
     * @param string $message
     * @param string $level This may be info, error, debug
     */
    private function logPendingDocumentInfoStatus($documentId, $message, $level)
    {
		$this->updatePendingDocumentStatus($documentId, $message, $level);
		global $default;

		switch ($level)
		{
			case 'debug':
				if ($this->debug)
				{
					$default->log->debug($message);
				}
				break;
			default:
				$default->log->$level($message);
		}
    }



	public function getExtractor($extractorClass)
	{
		if (empty($extractorClass))
		{
			return null;
		}

		$includeFile = SEARCH2_INDEXER_DIR . 'extractors/' . $extractorClass . '.inc.php';
		if (!file_exists($includeFile))
		{
			throw new Exception("Extractor file does not exist: $includeFile");
		}

		require_once($includeFile);

        if (!class_exists($extractorClass))
        {
        	throw new Exception("Extractor '$classname' not defined in file: $includeFile");
        }

        $extractor = new $extractorClass();

        if (!($extractor instanceof DocumentExtractor))
		{
        	throw new Exception("Class $classname was expected to be of type DocumentExtractor");
		}

        return $extractor;
	}

	public static function getIndexingQueue($problemItemsOnly=true)
	{

		if ($problemItemsOnly)
		{
			$sql = "SELECT
	        			iff.document_id, iff.indexdate, mt.filetypes, mt.mimetypes, me.name as extractor, iff.what, iff.status_msg, dcv.filename
					FROM
						index_files iff
						INNER JOIN documents d ON iff.document_id=d.id
						INNER JOIN document_metadata_version dmv ON d.metadata_version_id=dmv.id
						INNER JOIN document_content_version dcv ON dmv.content_version_id=dcv.id
						INNER JOIN mime_types mt ON dcv.mime_id=mt.id
						LEFT JOIN mime_extractors me ON mt.extractor_id=me.id
	 				WHERE
	 					(iff.status_msg IS NOT NULL AND iff.status_msg <> '') AND d.status_id=1
					ORDER BY indexdate ";
		}
		else
		{
			$sql = "SELECT
						iff.document_id, iff.indexdate, mt.filetypes, mt.mimetypes, me.name as extractor, iff.what, iff.status_msg, dcv.filename
					FROM
						index_files iff
						INNER JOIN documents d ON iff.document_id=d.id
						INNER JOIN document_metadata_version dmv ON d.metadata_version_id=dmv.id
						INNER JOIN document_content_version dcv ON dmv.content_version_id=dcv.id
						INNER JOIN mime_types mt ON dcv.mime_id=mt.id
						LEFT JOIN mime_extractors me ON mt.extractor_id=me.id
	 				WHERE
	 					(iff.status_msg IS NULL or iff.status_msg = '') AND d.status_id=1
					ORDER BY indexdate ";
		}
		$aResult = DBUtil::getResultArray($sql);

		return $aResult;
	}

	public static function getPendingIndexingQueue()
	{
		return Indexer::getIndexingQueue(false);
	}

	public function updateIndexStats()
	{
	    $optimisationDate = KTUtil::getSystemSetting('luceneOptimisationDate', '');

	    $noOptimisation = false;
	    if ($optimisationDate == '')
	    {
	        $optimisationDate = _kt('N/A');
	        $optimisationPeriod = $optimisationDate;
	    }
	    else
	    {
	        $optimisationPeriod = KTUtil::computePeriodToDate($optimisationDate, null, true);
	        $noOptimisation = $optimisationPeriod['days'] > 2;
	        $optimisationPeriod = $optimisationPeriod['str'];
	        $optimisationDate = date('Y-m-d H:i:s', $optimisationDate);
	    }

	    $indexingDate = KTUtil::getSystemSetting('luceneIndexingDate', '');
	    if ($indexingDate == '')
	    {
	        $indexingDate = _kt('N/A');
	        $indexingPeriod = $indexingDate;
	    }
	    else
	    {
	        $indexingPeriod = KTUtil::computePeriodToDate($indexingDate);
	        $indexingDate = date('Y-m-d H:i:s', $indexingDate);
	    }

	    $index = Indexer::get();
	    $docsInIndex = $index->getDocumentsInIndex();

	    // we are only interested in documents that are active
	    $sql = "SELECT count(*) as docsInQueue FROM index_files i inner join documents d on i.document_id = d.id where d.status_id=1";
	    $docsInQueue = DBUtil::getOneResultKey($sql, 'docsInQueue');

	    $sql = "SELECT count(*) as errorsInQueue FROM index_files i inner join documents d on i.document_id = d.id  where (i.status_msg is not null or i.status_msg <> '') and d.status_id=1";
	    $errorsInQueue = DBUtil::getOneResultKey($sql, 'errorsInQueue');

	    $sql = "SELECT count(*) as docsInRepository FROM documents where status_id=1";
	    $docsInRepository = DBUtil::getOneResultKey($sql, 'docsInRepository');

	    if ($docsInRepository == 0)
	    {
	        $indexingCoverage = '0.00%';
	        $queueCoverage = $indexingCoverage;
	    }
	    else
	    {
	        // compute indexing coverage
	        $indexingCoverage = _kt('Not Available');
	        if (is_numeric($docsInIndex))
	        {
	            $indexingCoverage = ($docsInIndex * 100) / $docsInRepository;
	            $indexingCoverage = number_format($indexingCoverage, 2, '.',',') . '%';
	        }

	        // compute queue coverage
	        $queueCoverage = _kt('Not Available');
	        if (is_numeric($docsInQueue))
	        {
	            $queueCoverage = ($docsInQueue * 100) / $docsInRepository;
	            $queueCoverage = number_format($queueCoverage, 2, '.',',') . '%';
	        }
	    }


	    $stats = array(
	    'optimisationDate'=>$optimisationDate,
	    'optimisationPeriod'=>$optimisationPeriod,
	    'indexingDate'=>$indexingDate,
	    'indexingPeriod'=>$indexingPeriod,
	    'docsInIndex'=>$docsInIndex,
	    'docsInQueue'=>$docsInQueue,
	    'errorsInQueue'=>$errorsInQueue,
	    'docsInRepository'=>$docsInRepository,
	    'indexingCoverage'=>$indexingCoverage,
	    'queueCoverage'=>$queueCoverage,
	    'noOptimisation'=>$noOptimisation
	    );

	    KTUtil::setSystemSetting('indexerStats', serialize($stats));

	    $indexer = Indexer::get();

	    $diagnosis = $indexer->diagnose();
	    KTUtil::setSystemSetting('indexerDiagnostics', serialize($diagnosis));

	    $extractorDiagnosis = $indexer->diagnoseExtractors();

	    KTUtil::setSystemSetting('extractorDiagnostics', serialize($extractorDiagnosis));
	}

    /**
     * The main function that may be called repeatedly to index documents.
     *
     * @param int $max Default 20
     */
    public function indexDocuments($max=null)
    {
    	global $default;
    	$config =& KTConfig::getSingleton();

    	/*$indexLockFile = $config->get('cache/cacheDirectory') . '/main.index.lock';
    	if (is_file($indexLockFile))
    	{
			$default->log->info('indexDocuments: main.index.lock seems to exist. it could be that the indexing is still underway.');
			$default->log->info('indexDocuments: Remove "' . $indexLockFile . '" if the indexing is not running or extend the frequency at which the background task runs!');
			return;
    	}
    	touch($indexLockFile);*/


    	$this->checkForRegisteredTypes();

    	if ($this->debug) $default->log->debug('indexDocuments: start');
    	if (!$this->doesDiagnosticsPass())
    	{
    		//unlink($indexLockFile);
    		if ($this->debug) $default->log->debug('indexDocuments: stopping - diagnostics problem. The dashboard will provide more information.');
    		return;
    	}

    	if (is_null($max))
    	{
			$max = $config->get('indexer/batchDocuments',20);
    	}

    	$this->loadExtractorHooks();

    	Indexer::clearoutDeleted();

    	$date = date('Y-m-d H:i:s');
    	// identify the indexers that must run
        // mysql specific limit!
        $sql = "SELECT
        			iff.document_id, mt.filetypes, mt.mimetypes, me.name as extractor, iff.what
				FROM
					index_files iff
					INNER JOIN documents d ON iff.document_id=d.id
					INNER JOIN document_metadata_version dmv ON d.metadata_version_id=dmv.id
					INNER JOIN document_content_version dcv ON dmv.content_version_id=dcv.id
					INNER JOIN mime_types mt ON dcv.mime_id=mt.id
					LEFT JOIN mime_extractors me ON mt.extractor_id=me.id
 				WHERE
 					(iff.processdate IS NULL or iff.processdate < date_sub('$date', interval 1 day)) AND dmv.status_id=1
				ORDER BY indexdate
 					LIMIT $max";
        $result = DBUtil::getResultArray($sql);
        if (PEAR::isError($result))
        {
        	//unlink($indexLockFile);
        	if ($this->debug) $default->log->debug('indexDocuments: stopping - db error');
        	return;
        }
        KTUtil::setSystemSetting('luceneIndexingDate', time());

        // bail if no work to do
        if (count($result) == 0)
        {
        	//unlink($indexLockFile);
        	if ($this->debug) $default->log->debug('indexDocuments: stopping - no work to be done');
            return;
        }

        // identify any documents that need indexing and mark them
        // so they are not taken in a followup run
		$ids = array();
		foreach($result as $docinfo)
		{
			$ids[] = $docinfo['document_id'];
		}

		// mark the documents as being processed

        $ids=implode(',',$ids);
        $sql = "UPDATE index_files SET processdate='$date' WHERE document_id in ($ids)";
        DBUtil::runQuery($sql);

        $extractorCache = array();
        $storageManager = KTStorageManagerUtil::getSingleton();

        $tempPath = $config->get("urls/tmpDirectory");

        foreach($result as $docinfo)
        {
        // increment indexed documents count
        Indexer::incrementCount();

        	$docId=$docinfo['document_id'];
        	$extension=$docinfo['filetypes'];
        	$mimeType=$docinfo['mimetypes'];
        	$extractorClass=$docinfo['extractor'];
        	$indexDocument = in_array($docinfo['what'], array('A','C'));
        	$indexDiscussion = in_array($docinfo['what'], array('A','D'));
			$this->indexingHistory = '';

        	$this->logPendingDocumentInfoStatus($docId, sprintf(_kt("Indexing docid: %d extension: '%s' mimetype: '%s' extractor: '%s'"), $docId, $extension,$mimeType,$extractorClass), 'debug');

        	if (empty($extractorClass))
        	{
        		/*

        		if no extractor is found and we don't need to index discussions, then we can remove the item from the queue.

        		*/
        		if ($indexDiscussion)
        		{
        			$indexDocument = false;
        			$this->logPendingDocumentInfoStatus($docId, sprintf(_kt("Not indexing docid: %d content because extractor could not be resolve. Still indexing discussion."), $docId), 'info');
        		}
        		else
        		{
        			Indexer::unqueueDocument($docId, sprintf(_kt("No extractor for docid: %d"),$docId));
        			continue;
        		}
        	}
        	else
        	{
        		/*

        		If an extractor is available, we must ensure it is enabled.

        		 */

	        	if (!$this->isExtractorEnabled($extractorClass))
				{
					$this->logPendingDocumentInfoStatus($docId, sprintf(_kt("diagnose: Not indexing docid: %d because extractor '%s' is disabled."), $docId, $extractorClass), 'info');
					continue;
				}
        	}

        	if ($this->debug)
        	{
        		$this->logPendingDocumentInfoStatus($docId, sprintf(_kt("Processing docid: %d.\n"),$docId), 'info');
        	}

        	$document = Document::get($docId);
        	if (PEAR::isError($document))
        	{
        		Indexer::unqueueDocument($docId,sprintf(_kt("indexDocuments: Cannot resolve document id %d: %s."),$docId, $document->getMessage()), 'error');
        		continue;
        	}

        	if ($this->restartCurrentBatch)
			{
			    Indexer::unqueueDocument($docId);
        		Indexer::index($docId, 'A');
			    continue;
			}


        	$filename = $document->getFileName();
        	if (substr($filename,0,1) == '~' || substr($filename,-1) == '~')
        	{
        		Indexer::unqueueDocument($docId,sprintf(_kt("indexDocuments: Filename for document id %d starts with a tilde (~). This is assumed to be a temporary file. This is ignored."),$docId), 'error');
        		continue;
        	}

        	$removeFromQueue = true;
        	if ($indexDocument)
        	{
        		if (array_key_exists($extractorClass, $extractorCache))
        		{
        			$extractor = $extractorCache[$extractorClass];
        		}
        		else
        		{
        			$extractor = $extractorCache[$extractorClass] = $this->getExtractor($extractorClass);
        		}

				if (!($extractor instanceof DocumentExtractor))
				{
					$this->logPendingDocumentInfoStatus($docId, sprintf(_kt("indexDocuments: extractor '%s' is not a document extractor class."),$extractorClass), 'error');
					continue;
				}



        		$version = $document->getMajorVersionNumber() . '.' . $document->getMinorVersionNumber();
        		$sourceFile = $storageManager->temporaryFile($document);

        		if (empty($sourceFile) || !is_file($sourceFile))
        		{
        			Indexer::unqueueDocument($docId,sprintf(_kt("indexDocuments: source file '%s' for document %d does not exist."),$sourceFile,$docId), 'error');
        			continue;
        		}

        		if ($extractor->needsIntermediateSourceFile())
        		{
        			//$extension =  pathinfo($document->getFileName(), PATHINFO_EXTENSION);

        			$intermediate = $tempPath . '/'. $docId . '.' . $extension;
        			$result = @copy($sourceFile, $intermediate);
        			if ($result === false)
        			{
        				$this->logPendingDocumentInfoStatus($docId, sprintf(_kt("Could not create intermediate file from document %d"),$docId), 'error');
        				// problem. lets try again later. probably permission related. log the issue.
        				continue;
        			}
        			$sourceFile = $intermediate;
        		}

        		$targetFile = tempnam($tempPath, 'ktindexer');

        		$extractor->setSourceFile($sourceFile);
        		$extractor->setMimeType($mimeType);
        		$extractor->setExtension($extension);
        		$extractor->setTargetFile($targetFile);
        		$extractor->setDocument($document);
        		$extractor->setIndexingStatus(null);
        		$extractor->setExtractionStatus(null);

        		$this->logPendingDocumentInfoStatus($docId, sprintf(_kt("Extra Info docid: %d Source File: '%s' Target File: '%s'"),$docId,$sourceFile,$targetFile), 'debug');

        		$this->executeHook($extractor, 'pre_extract');
				$this->executeHook($extractor, 'pre_extract', $mimeType);
				$removeFromQueue = false;

        		if ($extractor->extractTextContent())
        		{
        			// the extractor may need to create another target file
        			$targetFile = $extractor->getTargetFile();

        			$extractor->setExtractionStatus(true);
        			$this->executeHook($extractor, 'pre_index');
					$this->executeHook($extractor, 'pre_index', $mimeType);

					$title = $document->getName();
        			if ($indexDiscussion)
        			{
        				if (!$this->filterText($targetFile))
        				{
        					$this->logPendingDocumentInfoStatus($docId, sprintf(_kt("Problem filtering document %d"),$docId), 'error');
        				}
						else
						{
	        				$indexStatus = $this->indexDocumentAndDiscussion($docId, $targetFile, $title, $version);
    	    				$removeFromQueue = $indexStatus;
        					if (!$indexStatus)
        					{
        						$this->logPendingDocumentInfoStatus($docId, sprintf(_kt("Problem indexing document %d - indexDocumentAndDiscussion"),$docId), 'error');
        					}

        					$extractor->setIndexingStatus($indexStatus);
						}
        			}
        			else
        			{
        				if (!$this->filterText($targetFile))
        				{
        					$this->logPendingDocumentInfoStatus($docId, sprintf(_kt("Problem filtering document %d"),$docId), 'error');
        				}
						else
						{
							$indexStatus = $this->indexDocument($docId, $targetFile, $title, $version);
							$removeFromQueue = $indexStatus;

							if (!$indexStatus)
							{
								$this->logPendingDocumentInfoStatus($docId, sprintf(_kt("Problem indexing document %d - indexDocument"),$docId), 'error');
								$this->logPendingDocumentInfoStatus($docId, '<output>' . $extractor->output . '</output>', 'error');
							}

        					$extractor->setIndexingStatus($indexStatus);
						}
        			}

					$this->executeHook($extractor, 'post_index', $mimeType);
        			$this->executeHook($extractor, 'post_index');
        		}
        		else
        		{
        			$extractor->setExtractionStatus(false);
        			$this->logPendingDocumentInfoStatus($docId, sprintf(_kt("Could not extract contents from document %d"),$docId), 'error');
					$this->logPendingDocumentInfoStatus($docId, '<output>' . $extractor->output . '</output>', 'error');
        		}

				$this->executeHook($extractor, 'post_extract', $mimeType);
        		$this->executeHook($extractor, 'post_extract');

        		if ($extractor->needsIntermediateSourceFile())
        		{
        			@unlink($sourceFile);
        		}

        		@unlink($targetFile);

        	}
        	else
        	{
				$indexStatus = $this->indexDiscussion($docId);
				$removeFromQueue = $indexStatus;
        	}

        	if ($removeFromQueue)
        	{
        		Indexer::unqueueDocument($docId, sprintf(_kt("Done indexing docid: %d"),$docId));
        	}
        	else
        	{
        		if ($this->debug) $default->log->debug(sprintf(_kt("Document docid: %d was not removed from the queue as it looks like there was a problem with the extraction process"),$docId));
        	}
        }
        if ($this->debug) $default->log->debug('indexDocuments: done');
        //unlink($indexLockFile);
    }

    public function migrateDocuments($max=null)
    {
    	global $default;

    	$default->log->info(_kt('migrateDocuments: starting'));

    	if (!$this->doesDiagnosticsPass(true))
    	{
    		$default->log->info(_kt('migrateDocuments: stopping - diagnostics problem. The dashboard will provide more information.'));
    		return;
    	}

    	if (KTUtil::getSystemSetting('migrationComplete') == 'true')
    	{
    		$default->log->info(_kt('migrateDocuments: stopping - migration is complete.'));
    		return;
    	}

    	$config =& KTConfig::getSingleton();
    	if (is_null($max))
    	{
			$max = $config->get('indexer/batchMigrateDocument',500);
    	}

    	$lockFile = $config->get('cache/cacheDirectory') . '/migration.lock';
    	if (is_file($lockFile))
    	{
    		$default->log->info(_kt('migrateDocuments: stopping - migration lockfile detected.'));
    		return;
    	}
    	touch($lockFile);

    	$startTime = KTUtil::getSystemSetting('migrationStarted');
    	if (is_null($startTime))
    	{
    		KTUtil::setSystemSetting('migrationStarted', time());
    	}

    	$maxLoops = 5;

    	$max = ceil($max / $maxLoops);

		$start =KTUtil::getBenchmarkTime();
		$noDocs = false;
		$numDocs = 0;

    	for($loop=0;$loop<$maxLoops;$loop++)
    	{

    		$sql = "SELECT
        			document_id, document_text
				FROM
					document_text
				ORDER BY document_id
 					LIMIT $max";
    		$result = DBUtil::getResultArray($sql);
    		if (PEAR::isError($result))
    		{
    			$default->log->info(_kt('migrateDocuments: db error'));
    			break;
    		}

    		$docs = count($result);
    		if ($docs == 0)
    		{
    			$noDocs = true;
    			break;
    		}
    		$numDocs += $docs;

    		foreach($result as $docinfo)
    		{
    			$docId = $docinfo['document_id'];

    			$document = Document::get($docId);
    			if (PEAR::isError($document) || is_null($document))
    			{
    				$sql = "DELETE FROM document_text WHERE document_id=$docId";
    				DBUtil::runQuery($sql);
    				$default->log->error(sprintf(_kt('migrateDocuments: Could not get document %d\'s document! Removing content!'),$docId));
    				continue;
    			}

    			$version = $document->getMajorVersionNumber() . '.' . $document->getMinorVersionNumber();

    			$targetFile = tempnam($tempPath, 'ktindexer');

    			if (file_put_contents($targetFile, $docinfo['document_text']) === false)
    			{
    				$default->log->error(sprintf(_kt('migrateDocuments: Cannot write to \'%s\' for document id %d'), $targetFile, $docId));
    				continue;
    			}
    			// free memory asap ;)
    			unset($docinfo['document_text']);

    			$title = $document->getName();

    			$indexStatus = $this->indexDocumentAndDiscussion($docId, $targetFile, $title, $version);

    			if ($indexStatus)
    			{
    				$sql = "DELETE FROM document_text WHERE document_id=$docId";
    				DBUtil::runQuery($sql);
    			}
    			else
    			{
    				$default->log->error(sprintf(_kt("migrateDocuments: Problem indexing document %d"), $docId));
    			}

    			@unlink($targetFile);
    		}
    	}

    	@unlink($lockFile);

    	$time = KTUtil::getBenchmarkTime() - $start;

    	KTUtil::setSystemSetting('migrationTime', KTUtil::getSystemSetting('migrationTime',0) + $time);
    	KTUtil::setSystemSetting('migratedDocuments', KTUtil::getSystemSetting('migratedDocuments',0) + $numDocs);

    	$default->log->info(sprintf(_kt('migrateDocuments: stopping - done in %d seconds!'), $time));
    	if ($noDocs)
    	{
	    	$default->log->info(_kt('migrateDocuments: Completed!'));
	    	KTUtil::setSystemSetting('migrationComplete', 'true');
	    	schedulerUtil::deleteByName('Index Migration');
	    	$default->log->debug(_kt('migrateDocuments: Disabling \'Index Migration\' task by removing scheduler entry.'));
    	}
    }

    /**
     * Index a document. The base class must override this function.
     *
     * @param int $docId
     * @param string $textFile
     */
    protected abstract function indexDocument($docId, $textFile, $title, $version);


    public function updateDocumentIndex($docId, $text)
    {
    	$config = KTConfig::getSingleton();
    	$tempPath = $config->get("urls/tmpDirectory");
    	$tempFile = tempnam($tempPath,'ud_');

    	file_put_contents($tempFile, $text);

    	$document = Document::get($docId);
    	$title = $document->getDescription();
    	$version = $document->getVersion();

    	$result = $this->indexDocument($docId, $tempFile, $title, $version);

    	if (file_exists($tempFile))
    	{
    		unlink($tempFile);
    	}

    	return $result;
    }

    /**
     * Index a discussion. The base class must override this function.
     *
     * @param int $docId
     */
    protected abstract function indexDiscussion($docId);

    /**
     * Diagnose the indexer. e.g. Check that the indexing server is running.
     *
     */
	public abstract function diagnose();

    /**
     * Diagnose the extractors.
     *
     * @return array
     */
    public function diagnoseExtractors()
    {
		$diagnosis = $this->_diagnose($this->extractorPath, 'DocumentExtractor', 'Extractor.inc.php');
		$diagnosis = array_merge($diagnosis, $this->_diagnose($this->hookPath, 'Hook', 'Hook.inc.php'));

		return $diagnosis;
    }

    /**
     * This is a refactored diagnose function.
     *
     * @param string $path
     * @param string $class
     * @param string $extension
     * @return array
     */
    private function _diagnose($path, $baseclass, $extension)
    {
    	global $default;

    	$diagnoses = array();

    	$dir = opendir(SearchHelper::correctPath($path));
    	$extlen = - strlen($extension);

		while (($file = readdir($dir)) !== false)
		{
			if (substr($file,0,1) == '.')
			{
				continue;
			}
			if (substr($file,$extlen) != $extension)
			{
				$default->log->error(sprintf(_kt("diagnose: '%s' does not have extension '%s'."), $file, $extension));
				continue;
			}

			require_once($path . '/' . $file);

			$class = substr($file, 0, -8);
			if (!class_exists($class))
			{
				$default->log->error(sprintf(_kt("diagnose: class '%s' does not exist."), $class));
				continue;
			}

			if (!$this->isExtractorEnabled($class))
			{
				$default->log->debug(sprintf(_kt("diagnose: extractor '%s' is disabled."), $class));
				continue;
			}

			$extractor = new $class();
			if (!is_a($extractor, $baseclass))
			{
				$default->log->error(sprintf(_kt("diagnose(): '%s' is not of type DocumentExtractor"), $class));
				continue;
			}

			$types = $extractor->getSupportedMimeTypes();
			if (empty($types))
			{
				if ($this->debug) $default->log->debug(sprintf(_kt("diagnose: class '%s' does not support any types."), $class));
				continue;
			}

			$diagnosis=$extractor->diagnose();
			if (empty($diagnosis))
			{
				continue;
			}
			$diagnoses[$class] = array(
			'name'=>$extractor->getDisplayName(),
			'diagnosis'=>$diagnosis
			);

        }
        closedir($dir);

        return $diagnoses;
    }


    /**
     * Register the extractor types.
     *
     * @param boolean $clear. Optional. Defaults to false.
     */
    public function registerTypes($clear=false)
    {
    	if ($clear)
    	{
    		$this->clearExtractors();
    	}
    	$dir = opendir(SearchHelper::correctPath($this->extractorPath));
		while (($file = readdir($dir)) !== false)
		{
			if (substr($file,-17) == 'Extractor.inc.php')
			{
				require_once($this->extractorPath . '/' . $file);
				$class = substr($file, 0, -8);

				if (!class_exists($class))
				{
					// if the class does not exist, we can't do anything.
					continue;
				}

				$extractor = new $class;
				if ($extractor instanceof DocumentExtractor)
				{
					$extractor->registerMimeTypes();
				}
			}
        }
        closedir($dir);
    }

    /**
     * This is used as a possible obtimisation effort. It may be overridden in that case.
     *
     * @param int $docId
     * @param string $textFile
     */
    protected function indexDocumentAndDiscussion($docId, $textFile, $title, $version)
    {
    	$this->indexDocument($docId, $textFile, $title, $version);
    	$this->indexDiscussion($docId);
    }

    /**
     * Remove the document from the queue. This is normally called when it has been processed.
     *
     * @param int $docid
     */
    public static function unqueueDocument($docid, $reason=false, $level='debug')
    {
    	$sql = "DELETE FROM index_files WHERE document_id=$docid";
        DBUtil::runQuery($sql);
        if ($reason !== false)
        {
        	global $default;
        	$default->log->$level("Indexer: removing document $docid from the queue - $reason");
        }
    }

    /**
     * Run a query on the index.
     *
     * @param string $query
     * @return array
     */
    public abstract function query($query);

	/**
	 * Converts an integer to a string that can be easily compared and reversed.
	 *
	 * @param int $int
	 * @return string
	 */
	public static function longToString($int)
    {
    	$maxlen = 14;

        $a2z = array('a','b','c','d','e','f','g','h','i','j');
        $o29 = array('0','1','2','3','4','5','6','7','8','9');
        $l = str_pad('',$maxlen - strlen("$int"),'0') . $int;

        return str_replace($o29,  $a2z, $l);
    }

    /**
     * Converts a string to an integer.
     *
     * @param string $str
     * @return int
     */
	public static function stringToLong($str)
    {
        $a2z = array('a','b','c','d','e','f','g','h','i','j');
        $o29 = array('0','1','2','3','4','5','6','7','8','9');

        $int = str_replace($a2z, $o29, $str) + 0;

        return $int;
    }

    /**
     * Possibly we can optimise indexes. This method must be overriden.
     * The new function must call the parent!
     *
     */
    public function optimise()
    {
    	KTUtil::setSystemSetting('luceneOptimisationDate', time());
    }

    /**
     * Shuts down the indexer
     *
     */
    public function shutdown()
    {
    	// do nothing generally
    }

    /**
     * Returns the name of the indexer.
     *
     * @return string
     */
    public abstract function getDisplayName();


    /**
     * Returns the number of non-deleted documents in the index.
     *
     * @return int
     */
    public abstract function getDocumentsInIndex();

    public abstract function isDocumentIndexed($documentId);

    /**
     * Returns the path to the index directory
     *
     * @return string
     */
    public function getIndexDirectory()
    {
    	$config = KTConfig::getSingleton();
    	$directory = $config->get('indexer/luceneDirectory');
    	return $directory;
    }
}

?>