<?php
/* $Id$ */
namespace Mammut\Cache;

(defined('MAMMUT') && (basename(__FILE__) != basename($_SERVER['PHP_SELF']))) or die('ACCESS DENIED');

use \Mammut\Exception\ExtensionException;
use \Mammut\Crypt\MCrypt;

/**
 * APC adapter
 *
 * Advanced PHP Cache implementation of cache interface
 *
 * @author Stefan Daurer <s.daurer@q-spot.org>
 * @package Mammut\Cache
 */
class APC extends \Mammut\StrictObject implements \Mammut\Cache\iCache {
	protected $prefix;
	protected $secret;
	
	/**
	 *
	 * @var MCrypt
	 */
	protected $crypt;
	private $hits = 0;

	public function __construct($prefix, $secret = false) {
		if(!extension_loaded('apc'))
			throw new ExtensionException('apc');
		$this->prefix = $prefix;
		// encryption settings (planned)
		$this->secret = $secret;
		if(!empty($this->secret)) {
			$this->crypt = new MCrypt(MCrypt::CIPHER_AES);
			$this->crypt->setKey($secret);
		}
	}
	
	protected function genKey($key) {
		if (!is_scalar($key))
			throw new \InvalidArgumentException('$key is not scalar');
		$key = $this->prefix . $key;
		return $key;
	}

	public function set($key, $value, $ttl) {
		$key = $this->genKey($key);
		if ($value instanceof \Closure)
			$value = $value();		
		if(is_object($this->crypt))
			$value = $this->crypt->encode(serialize($value));
		apc_store($key, $value, $ttl);
	}

	public function get($key, $default = NULL) {
		$key = $this->genKey($key);
		$value = apc_fetch($key, $success);
		if(!$success)
			return $default;
		if(is_object($this->crypt))
			$value = unserialize($this->crypt->decode($value));
		
		$this->hits++;
		return $value;
	}

	public function delete($key) {
		$key = $this->genKey($key);
		apc_delete($key);
	}

	public function keyExists($key) {
		$key = $this->genKey($key);
		if(function_exists('apc_exists')) // apc_exists is only avaible in apc >= 3.1.4
			return apc_exists($key);
		apc_fetch($key, $success);
		return $success;
	}

	public function clear() {
		apc_clear_cache('user');
	}

	public function getHits() {
		return $this->hits;
	}
}