<?php

/**
* @package   com_zoo
* @author    YOOtheme http://www.yootheme.com
* @copyright Copyright (C) YOOtheme GmbH
* @license   http://www.gnu.org/licenses/gpl.html GNU/GPL
*/


/**

 * The cache helper class.

 *

 * @package Component.Helpers

 * @since 2.0

 */

class CacheHelper extends AppHelper {



	/**

	 * Creates an AppCache instance

	 *

	 * @param string $file Path to cache file

	 * @param boolean $hash Wether the key should be hashed

	 * @param int $lifetime The values lifetime

	 *

	 * @return AppCache

	 *

	 * @since 2.0

	 */

	public function create($file, $hash = true, $lifetime = null) {

		$cache = $this->app->object->create('AppCache', array($file, $hash, $lifetime));

		$this->app->zoo->putIndexFile(dirname($file));

		return $cache;

	}



}



/**

 * The cache class.

 *

 * @package Component.Helpers

 * @since 2.0

 */

class AppCache {



	/**

	 * Path to cache file

	 *

	 * @var string

	 * @since 2.0

	 */

	protected $_file = 'config.txt';



	/**

	 * Path to cache file

	 *

	 * @var array

	 * @since 2.0

	 */

	protected $_items = array();



	/**

	 * marks cache dirty

	 *

	 * @var boolean

	 * @since 2.0

	 */

	protected $_dirty = false;



	/**

	 * The cached items

	 *

	 * @var boolean

	 * @since 2.0

	 */

	protected $_hash = true;



	/**

	 * Class constructor

	 *

	 * @param string $file Path to cache file

	 * @param boolean $hash Wether the key should be hashed

	 * @param int $lifetime The values lifetime

	 * @since 2.0

	 */

	public function __construct($file, $hash = true, $lifetime = null) {



		// if cache file doesn't exist, create it

		if (!JFile::exists($file)) {

			JFolder::create(dirname($file));

			$buffer = '';

			JFile::write($file, $buffer);

		}



		// set file and parse it

		$this->_file = $file;

		$this->_hash = $hash;

		$this->_parse();



		// clear out of date values

		if ($lifetime) {

			$lifetime = (int) $lifetime;

			$remove = array();

			foreach ($this->_items as $key => $value) {

				if ((time() - $value['timestamp']) > $lifetime) {

					$remove[] = $key;

				}

			}

			foreach ($remove as $key) {

				unset($this->_items[$key]);

			}

		}

	}



	/**

	 * Check if the cache file is writable and readable

	 *

	 * @return boolean If the cache can be used

	 *

	 * @since 2.0

	 */

	public function check() {

		return is_readable($this->_file) && is_writable($this->_file);

	}



	/**

	 * Get a cache content

	 *

	 * @param  string $key The key

	 *

	 * @return mixed      The cache content

	 *

	 * @since 2.0

	 */

	public function get($key) {

		if ($this->_hash)

			$key = md5($key);

		if (!array_key_exists($key, $this->_items))

			return null;



		return $this->_items[$key]['value'];

	}



	/**

	 * Set a cache content

	 *

	 * @param string $key   The key

	 * @param mixed $value The value

	 *

	 * @return AppCache $this for chaining support

	 *

	 * @since 2.0

	 */

	public function set($key, $value) {

		if ($this->_hash)

			$key = md5($key);

		if (array_key_exists($key, $this->_items) && @$this->_items[$key]['value'] == $value)

			return $this;



		$this->_items[$key]['value'] = $value;

		$this->_items[$key]['timestamp'] = time();

		$this->_dirty = true;

		return $this;

	}



	/**

	 * Parse the cache file

	 *

	 * @return AppCache $this for chaining support

	 *

	 * @since 2.0

	 */

	protected function _parse() {

		$content = JFile::read($this->_file);

		if (!empty($content)) {

			$items = json_decode($content, true);

			if (is_array($items)) {

				$this->_items = $items;

			}

		}

		return $this;

	}



	/**

	 * Save the cache file if it was changed

	 *

	 * @return AppCache $this for chaining support

	 *

	 * @since 2.0

	 */

	public function save() {

		if ($this->_dirty) {

			JFile::write($this->_file, json_encode($this->_items));

		}

		return $this;

	}



	/**

	 * Clear the cache file

	 *

	 * @return AppCache $this for chaining support

	 */

	public function clear() {

		$this->_items = array();

		$this->_dirty = true;

		return $this;

	}



}



/**

 * AppCacheException identifies an Exception in the AppCache class

 * @see AppCache

 */

class AppCacheException extends AppException {}