<?php
if (!defined('LIB_CACHE_ENABLE'))
{
    define('LIB_CACHE_ENABLE', 0);
    Logger::getLogger('cache')->error('setting LIB_CACHE_ENABLE is not defined, ' .
            'turning cache off. define LIB_CACHE_ENABLE to 1 to enable cache');
}

interface Cache
{
    public function setKey($key);
    public function get($key = null);
    public function set($value, $expire = 3600, $key = null);
    public function delete($key = null);

	public function getInstance();
}

/**
 * todo: docme
 * @author Cory
 * @version 1.0
 */
abstract class AbstractCache
{
	protected $_log;
	protected $_key;
	protected $_origKey;

	const CACHE_MISS = 'CACHEMISS';

	/**
	 * todo: docme
	 */
	protected function __construct()
	{
        $this->_log = Logger::getLogger('cache');
		$this->_key = null;
    }

	/**
	 * todo: docme
	 * @param string $key the new cache key to use for the next calls to get, set, delete
	 *    if $key is not a string, it will be serialized()
	 */
	public function setKey($key)
	{
		$this->_origKey = $key;
		if (!is_string($key))
			$key = serialize($key);

		$this->_key = $key;

        // hash it if we need to
        if (strspn($this->_key, 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_.-') != strlen($this->_key))
			$this->_key = md5($this->_key);

		$this->_log->trace("new key: [{$this->_origKey}] => {$this->_key}");
		return $this;
	}

	
	/**
	 * @return mixed something that was cached
	 */
	abstract public function get($key = null);
	

	/**
	 * @return true on success
	 */
	abstract public function set($value, $expire = 3600, $key = null);

	/**
	 * @return true on success
	 */
	abstract  public function delete($key = null);

}