<?php
  
  namespace OCA\Search_Lucene;
  
  use \OC\Files\Filesystem;
  use \OCP\User;
  use \OCP\Util;
  
  /**
   * @author Jörn Dreyer <jfd@butonic.de>
   */
  class Lucene extends \OC_Search_Provider {
  
  	/**
  	 * classname which used for hooks handling
  	 * used as signalclass in OC_Hooks::emit()
  	 */
  	const CLASSNAME = 'Lucene';
  
  	/**
  	 * opens or creates the users lucene index
  	 * 
  	 * stores the index in <datadirectory>/<user>/lucene_index
  	 * 
  	 * @author Jörn Dreyer <jfd@butonic.de>
  	 *
  	 * @return Zend_Search_Lucene_Interface 
  	 */
  	public static function openOrCreate($user = null) {
  
  		if ($user == null) {
  			$user = User::getUser();
  		}
  
  		try {
  			
  			\Zend_Search_Lucene_Analysis_Analyzer::setDefault(
  				new \Zend_Search_Lucene_Analysis_Analyzer_Common_TextNum_CaseInsensitive()
  			); //let lucene search for numbers as well as words
  			
  			// Create index
  			//$ocFilesystemView = OC_App::getStorage('search_lucene'); // encrypt the index on logout, decrypt on login
  
  			$indexUrl = \OC_User::getHome($user) . '/lucene_index';
  			if (file_exists($indexUrl)) {
  				$index = \Zend_Search_Lucene::open($indexUrl);
  			} else {
  				$index = \Zend_Search_Lucene::create($indexUrl);
  				//todo index all user files
  			}
  		} catch ( Exception $e ) {
  			Util::writeLog(
  				'search_lucene',
  				$e->getMessage().' Trace:
  '.$e->getTraceAsString(),
  				Util::ERROR
  			);
  			return null;
  		}
  		
  
  		return $index;
  	}
  
  	/**
  	 * optimizes the lucene index
  	 * 
  	 * 
  	 * @author Jörn Dreyer <jfd@butonic.de>
  	 * 
  	 * @param Zend_Search_Lucene_Interface $index an optional index
  	 * 
  	 * @return void
  	 */
  	static public function optimizeIndex(
  		\Zend_Search_Lucene_Interface $index = null
  	) {
  
  		if ($index === null) {
  			$index = self::openOrCreate();
  		}
  
  		Util::writeLog(
  			'search_lucene',
  			'optimizing index ',
  			Util::DEBUG
  		);
  
  		$index->optimize();
  
  	}
  
  	/**
  	 * upates a file in the lucene index
  	 * 
  	 * 1. the file is deleted from the index
  	 * 2. the file is readded to the index
  	 * 3. the file is marked as index in the status table
  	 * 
  	 * @author Jörn Dreyer <jfd@butonic.de>
  	 * 
  	 * @param Zend_Search_Lucene_Document $doc  the document to store for the path
  	 * @param string                      $path path to the document to update
  	 * 
  	 * @return void
  	 */
  	static public function updateFile(
  		\Zend_Search_Lucene_Document $doc,
  		$path = '',
  		$user = null,
  		\Zend_Search_Lucene_Interface $index = null
  	) {
  
  		if ($index === null) {
  			$index = self::openOrCreate($user);
  		}
  		
  		// TODO profile perfomance for searching before adding to index
  		self::deleteFile($path, $user, $index);
  
  		Util::writeLog(
  			'search_lucene',
  			'adding ' . $path ,
  			Util::DEBUG
  		);
  		
  		// Add document to the index
  		$index->addDocument($doc);
  
  		$index->commit();
  
  	}
  
  	/**
  	 * removes a file frome the lucene index
  	 * 
  	 * @author Jörn Dreyer <jfd@butonic.de>
  	 * 
  	 * @param string                       $path  path to the document to remove from the index
  	 * @param Zend_Search_Lucene_Interface $index optional can be passed ro reuse an existing instance
  	 * 
  	 * @return void
  	 */
  	static public function deleteFile(
  		$path,
  		$user = null,
  		\Zend_Search_Lucene_Interface $index = null
  	) {
  
  		if ( $path === '' ) {
  			//ignore the empty path element
  			return;
  		}
  
  		if (is_null($user)) {
  			$view = Filesystem::getView();
  			$user = \OCP\User::getUser();
  		} else {
  			$view = new \OC\Files\View('/' . $user . '/files');
  		}
  
  		if ( ! $view ) {
  			Util::writeLog(
  				'search_lucene',
  				'could not resolve filesystem view',
  				Util::WARN
  			);
  			return false;
  		}
  
  		if ($index === null) {
  			$index = self::openOrCreate($user);
  		}
  
  		$root= $view->getRoot();
  		$pk = md5($root.$path);
  
  		Util::writeLog(
  			'search_lucene',
  			'searching hits for pk:' . $pk,
  			Util::DEBUG
  		);
  
  
  		$hits = $index->find( 'pk:' . $pk ); //id would be internal to lucene
  
  		Util::writeLog(
  			'search_lucene',
  			'found ' . count($hits) . ' hits ',
  			Util::DEBUG
  		);
  
  		foreach ($hits as $hit) {
  			Util::writeLog(
  				'search_lucene',
  				'removing ' . $hit->id . ':' . $hit->path . ' from index',
  				Util::DEBUG
  			);
  			$index->delete($hit);
  		}
  	}
  
  	/**
  	 * performs a search on the users index
  	 * 
  	 * @author Jörn Dreyer <jfd@butonic.de>
  	 * 
  	 * @param string $query lucene search query
  	 * @return array of OC_Search_Result
  	 */
  	public function search($query){
  		$results=array();
  		if ( $query !== null ) {
  			// * query * kills performance for bigger indexes
  			// query * works ok
  			// query is still best
  			//FIXME emulates the old search but breaks all the nice lucene search query options
  			//$query = '*' . $query . '*';
  			//if (strpos($query, '*')===false) {
  			//	$query = $query.='*'; // append query *, works ok
  			//	TODO add end user guide for search terms ... 
  			//}
  			try {
  				$index = self::openOrCreate(); 
  				//default is 3, 0 needed to keep current search behaviour
  				//Zend_Search_Lucene_Search_Query_Wildcard::setMinPrefixLength(0); 
  				
  				//$term  = new Zend_Search_Lucene_Index_Term($query);
  				//$query = new Zend_Search_Lucene_Search_Query_Term($term);
  				
  				$hits = $index->find($query);
  
  				//limit results. we cant show more than ~30 anyway. TODO use paging later
  				for ($i = 0; $i < 30 && $i < count($hits); $i++) {
  					$results[] = self::asOCSearchResult($hits[$i]);
  				}
  
  			} catch ( Exception $e ) {
  				Util::writeLog(
  					'search_lucene',
  					$e->getMessage().' Trace:
  '.$e->getTraceAsString(),
  					Util::ERROR
  				);
  			}
  
  		}
  		return $results;
  	}
  
  	/**
  	 * converts a zend lucene search object to a OC_SearchResult
  	 *
  	 * Example:
  	 * 
  	 * Text | Some Document.txt
  	 *      | /path/to/file, 148kb, Score: 0.55
  	 * 
  	 * @author Jörn Dreyer <jfd@butonic.de>
  	 *
  	 * @param Zend_Search_Lucene_Search_QueryHit $hit The Lucene Search Result
  	 * @return OC_Search_Result an OC_Search_Result
  	 */
  	private static function asOCSearchResult(\Zend_Search_Lucene_Search_QueryHit $hit) {
  
  		$mimeBase = self::baseTypeOf($hit->mimetype);
  
  		switch($mimeBase){
  			case 'audio':
  				$type='Music';
  				break;
  			case 'text':
  				$type='Text';
  				break;
  			case 'image':
  				$type='Images';
  				break;
  			default:
  				if ($hit->mimetype=='application/xml') {
  					$type='Text';
  				} else {
  					$type='Files';
  				}
  		}
  
  		switch ($hit->mimetype) {
  			case 'httpd/unix-directory':
  				$url = Util::linkTo('files', 'index.php') . '?dir='.$hit->path;
  				break;
  			default:
  				$url = \OC::getRouter()->generate('download', array('file'=>$hit->path));
  		}
  		
  		return new \OC_Search_Result(
  			basename($hit->path),
  			dirname($hit->path)
  				. ', ' . \OC_Helper::humanFileSize($hit->size)
  				. ', Score: ' . number_format($hit->score, 2),
  			$url,
  			$type
  		);
  	}
  
  	/**
  	 * get the base type of a mimetype string
  	 * 
  	 * returns 'text' for 'text/plain'
  	 * 
  	 * @author Jörn Dreyer <jfd@butonic.de>
  	 * 
  	 * @param string $mimetype mimetype
  	 * @return string basetype 
  	 */
  	public static function baseTypeOf($mimetype) {
  		return substr($mimetype, 0, strpos($mimetype, '/'));
  	}
  
  }