<?php
  /**
   * Copyright (c) 2012 Robin Appelman <icewind@owncloud.com>
   * This file is licensed under the Affero General Public License version 3 or
   * later.
   * See the COPYING-README file.
   */
  
  namespace OC\Files\Cache;
  
  /**
   * check the storage backends for updates and change the cache accordingly
   */
  class Watcher {
  	/**
  	 * @var \OC\Files\Storage\Storage $storage
  	 */

  	protected $storage;

  
  	/**
  	 * @var Cache $cache
  	 */

  	protected $cache;

  
  	/**
  	 * @var Scanner $scanner;
  	 */

  	protected $scanner;

  
  	/**
  	 * @param \OC\Files\Storage\Storage $storage
  	 */
  	public function __construct(\OC\Files\Storage\Storage $storage) {
  		$this->storage = $storage;
  		$this->cache = $storage->getCache();
  		$this->scanner = $storage->getScanner();
  	}
  
  	/**
  	 * check $path for updates
  	 *
  	 * @param string $path

  	 * @return boolean true if path was updated, false otherwise

  	 */
  	public function checkUpdate($path) {
  		$cachedEntry = $this->cache->get($path);

  		if ($this->storage->hasUpdated($path, $cachedEntry['storage_mtime'])) {

  			if ($this->storage->is_dir($path)) {
  				$this->scanner->scan($path, Scanner::SCAN_SHALLOW);
  			} else {
  				$this->scanner->scanFile($path);
  			}
  			if ($cachedEntry['mimetype'] === 'httpd/unix-directory') {
  				$this->cleanFolder($path);
  			}
  			$this->cache->correctFolderSize($path);

  			return true;

  		}

  		return false;

  	}
  
  	/**
  	 * remove deleted files in $path from the cache
  	 *
  	 * @param string $path
  	 */
  	public function cleanFolder($path) {
  		$cachedContent = $this->cache->getFolderContents($path);
  		foreach ($cachedContent as $entry) {
  			if (!$this->storage->file_exists($entry['path'])) {
  				$this->cache->remove($entry['path']);
  			}
  		}
  	}
  }