<?php
  /**
   * Copyright (c) 2012 Bart Visscher <bartv@thisnet.nl>
   * This file is licensed under the Affero General Public License version 3 or
   * later.
   * See the COPYING-README file.
   */
  
  namespace OC;
  
  class Cache {
  	/**
  	 * @var Cache $user_cache
  	 */
  	static protected $user_cache;
  	/**
  	 * @var Cache $global_cache
  	 */
  	static protected $global_cache;
  
  	/**
  	 * get the global cache
  	 * @return Cache
  	 */
  	static public function getGlobalCache() {
  		if (!self::$global_cache) {
  			self::$global_cache = new Cache\FileGlobal();
  		}
  		return self::$global_cache;
  	}
  
  	/**
  	 * get the user cache
  	 * @return Cache
  	 */
  	static public function getUserCache() {
  		if (!self::$user_cache) {
  			self::$user_cache = new Cache\File();
  		}
  		return self::$user_cache;
  	}
  
  	/**
  	 * get a value from the user cache
  	 * @param string $key
  	 * @return mixed
  	 */
  	static public function get($key) {
  		$user_cache = self::getUserCache();
  		return $user_cache->get($key);
  	}
  
  	/**
  	 * set a value in the user cache
  	 * @param string $key
  	 * @param mixed $value
  	 * @param int $ttl
  	 * @return bool
  	 */
  	static public function set($key, $value, $ttl=0) {
  		if (empty($key)) {
  			return false;
  		}
  		$user_cache = self::getUserCache();
  		return $user_cache->set($key, $value, $ttl);
  	}
  
  	/**
  	 * check if a value is set in the user cache
  	 * @param string $key
  	 * @return bool
  	 */
  	static public function hasKey($key) {
  		$user_cache = self::getUserCache();
  		return $user_cache->hasKey($key);
  	}
  
  	/**
  	 * remove an item from the user cache
  	 * @param string $key
  	 * @return bool
  	 */
  	static public function remove($key) {
  		$user_cache = self::getUserCache();
  		return $user_cache->remove($key);
  	}
  
  	/**
  	 * clear the user cache of all entries starting with a prefix
  	 * @param string $prefix (optional)
  	 * @return bool
  	 */
  	static public function clear($prefix='') {
  		$user_cache = self::getUserCache();
  		return $user_cache->clear($prefix);
  	}
  
  	/**
  	 * creates cache key based on the files given

  	 * @param string[] $files

  	 * @return string
  	 */
  	static public function generateCacheKeyFromFiles($files) {
  		$key = '';
  		sort($files);
  		foreach($files as $file) {
  			$stat = stat($file);
  			$key .= $file.$stat['mtime'].$stat['size'];
  		}
  		return md5($key);
  	}
  }