<?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\Mount;

  use \OC\Files\Filesystem;
  use OC\Files\Storage\Loader;
  use OC\Files\Storage\Storage;

  class Mount {

  	/**
  	 * @var \OC\Files\Storage\Storage $storage
  	 */

  	protected $storage = null;
  	protected $class;
  	protected $storageId;
  	protected $arguments = array();
  	protected $mountPoint;

  
  	/**

  	 * @var \OC\Files\Storage\Loader $loader
  	 */
  	private $loader;
  
  	/**

  	 * @param string|\OC\Files\Storage\Storage $storage

  	 * @param string $mountpoint

  	 * @param array $arguments (optional)\
  	 * @param \OC\Files\Storage\Loader $loader

  	 */

  	public function __construct($storage, $mountpoint, $arguments = null, $loader = null) {

  		if (is_null($arguments)) {
  			$arguments = array();
  		}

  		if (is_null($loader)) {
  			$this->loader = new Loader();
  		} else {
  			$this->loader = $loader;
  		}

  		$mountpoint = $this->formatPath($mountpoint);
  		if ($storage instanceof Storage) {

  			$this->class = get_class($storage);

  			$this->storage = $this->loader->wrap($mountpoint, $storage);

  		} else {
  			// Update old classes to new namespace
  			if (strpos($storage, 'OC_Filestorage_') !== false) {
  				$storage = '\OC\Files\Storage\\' . substr($storage, 15);
  			}
  			$this->class = $storage;
  			$this->arguments = $arguments;
  		}
  		$this->mountPoint = $mountpoint;

  	}
  
  	/**

  	 * get complete path to the mount point, relative to data/
  	 *

  	 * @return string
  	 */
  	public function getMountPoint() {
  		return $this->mountPoint;
  	}
  
  	/**

  	 * get name of the mount point
  	 *
  	 * @return string
  	 */
  	public function getMountPointName() {
  		return basename(rtrim($this->mountPoint, '/'));
  	}
  
  	/**
  	 * @param string $mountPoint new mount point
  	 */
  	public function setMountPoint($mountPoint) {
  		$this->mountPoint = $mountPoint;
  	}
  
  	/**

  	 * create the storage that is mounted
  	 *

  	 * @return \OC\Files\Storage\Storage
  	 */
  	private function createStorage() {
  		if (class_exists($this->class)) {
  			try {

  				return $this->loader->load($this->mountPoint, $this->class, $this->arguments);

  			} catch (\Exception $exception) {

  				if ($this->mountPoint === '/') {
  					// the root storage could not be initialized, show the user!
  					throw new \Exception('The root storage could not be initialized. Please contact your local administrator.', $exception->getCode(), $exception);
  				} else {
  					\OC_Log::write('core', $exception->getMessage(), \OC_Log::ERROR);
  				}

  				return null;
  			}
  		} else {
  			\OC_Log::write('core', 'storage backend ' . $this->class . ' not found', \OC_Log::ERROR);
  			return null;
  		}
  	}
  
  	/**
  	 * @return \OC\Files\Storage\Storage
  	 */
  	public function getStorage() {
  		if (is_null($this->storage)) {
  			$this->storage = $this->createStorage();
  		}
  		return $this->storage;
  	}
  
  	/**
  	 * @return string
  	 */
  	public function getStorageId() {
  		if (!$this->storageId) {
  			if (is_null($this->storage)) {
  				$storage = $this->createStorage(); //FIXME: start using exceptions
  				if (is_null($storage)) {
  					return null;
  				}
  				$this->storage = $storage;
  			}
  			$this->storageId = $this->storage->getId();
  			if (strlen($this->storageId) > 64) {
  				$this->storageId = md5($this->storageId);
  			}
  		}
  		return $this->storageId;
  	}
  
  	/**
  	 * @param string $path
  	 * @return string
  	 */
  	public function getInternalPath($path) {
  		if ($this->mountPoint === $path or $this->mountPoint . '/' === $path) {
  			$internalPath = '';
  		} else {
  			$internalPath = substr($path, strlen($this->mountPoint));
  		}

  		// substr returns false instead of an empty string, we always want a string
  		return (string)$internalPath;

  	}
  
  	/**
  	 * @param string $path
  	 * @return string
  	 */

  	private function formatPath($path) {

  		$path = Filesystem::normalizePath($path);
  		if (strlen($path) > 1) {
  			$path .= '/';
  		}
  		return $path;
  	}
  
  	/**

  	 * @param callable $wrapper

  	 */

  	public function wrapStorage($wrapper) {

  		$this->storage = $wrapper($this->mountPoint, $this->getStorage());

  	}
  }