<?php
/* $Id$ */
namespace Mammut\Cache;

(defined('MAMMUT') && (basename(__FILE__) != basename($_SERVER['PHP_SELF']))) or die('ACCESS DENIED');

use \Mammut\Exception\ExtensionException;

/**
 * Memcache adapter
 *
 * Memcache API implementation of cache interface. This could be used with many key-value
 * storage solutions
 * like memcached, couchbase, memcachedb or the memcache-interface of more recent mysql
 * versions.
 *
 * @author Stefan Daurer <s.daurer@q-spot.org>
 * @package Mammut\Cache
 */
class Memcache extends \Mammut\StrictObject implements \Mammut\Cache\iCache {
	const OPT_BACKEND = 'backend';
	
	/**
	 *
	 * @var Memcache
	 */
	protected $memcache;
	
	/**
	 *
	 * @var \Memcached
	 */
	protected $memcached;
	private $hits = 0;
	private $api = false;
	private $prefix;

	public static function getBackendType() {
		// prefer memcached, which is linked to libmemcached
		if(extension_loaded('memcached'))
			return 'memcached';
			// fall back to libless extension, if avaible
		if(extension_loaded('memcache'))
			return 'memcache';
		return false;
	}

	public function __construct($server, $port, $prefix, array $options = array()) {
		if(!(extension_loaded('memcache') || extension_loaded('memcached')))
			throw new ExtensionException('memcache(d)');
		$this->api = isset($options[self::OPT_BACKEND]) ? $options[self::OPT_BACKEND] : self::getBackendType();
		switch($this->api) {
			case 'memcached':
				$this->memcached = new \Memcached();
				$this->memcached->setOption(\Memcached::OPT_PREFIX_KEY, $prefix);
				if(key_exists('user', $options)) {
					if(!method_exists($this->memcached, 'setSaslAuthData'))
						throw new \RuntimeException('extension is build without sasl support, authentication not avaible');
					$this->memcached->setSaslAuthData($options['user'], $options['passwd']);
				}
				if(is_array($server))
					$this->memcached->addServers($server);
				else
					$this->memcached->addServer($server, $port);
			break;
			case 'memcache':
				$this->memcache = new \Memcache();
				$this->memcache->pconnect($server, $port, 30);
				$this->prefix = $prefix;
			break;
		}
	}

	public function set($key, $value, $ttl) {
		if ($value instanceof \Closure)
			$value = $value();
		switch($this->api) {
			case 'memcached':
				return $this->memcached->set($key, $value, $ttl);
			case 'memcache':
				$key = $this->prefix . $key;
				return $this->memcache->set($key, $value, 0, $ttl);
		}
	}

	public function get($key, $default = NULL) {
		$this->api == 'memcached' || $key = $this->prefix . $key;
		$value = $this->{$this->api}->get($key);
		if(is_null($value) || $value === false) {
			if ($default instanceof \Closure)
				$value = $default();
			else
				$value = $default;
		}
		else
			$this->hits++;
		return $value;
	}

	public function delete($key) {
		$this->api == 'memcached' || $key = $this->prefix . $key;
		$this->{$this->api}->delete($key);
	}

	public function keyExists($key) {
		switch($this->api) {
			case 'memcached':
				return (boolean) ($this->memcached->get($key) !== false);
			case 'memcache':
				$key = $this->prefix . $key;
				return (boolean) ($this->memcache->get($key) !== false);
		}
	}

	public function clear() {
		$this->{$this->api}->flush();
	}

	public function getHits() {
		return $this->hits;
	}

	public function getStatistics() {
		$result = array();
		switch($this->api) {
			case 'memcached':
				var_dump($this->memcached);
				var_dump($this->memcached->getStats());
				var_dump($this->memcached->getVersion());
				$stats = $this->memcached->getStats();
				if(!empty($stats)) {
					foreach($stats as $server=>$serverstats) {
						$result[$server]['version'] = $serverstats['version'];
					}
				}
			break;
			case 'memcache':
				var_dump($this->memcache);
				var_dump($this->memcache->getStats());
				var_dump($this->memcache->getExtendedStats());
				// var_dump($this->memcached->getVersion());
				// $stats = $this->memcached->getStats();
				if(!empty($stats)) {
					foreach($stats as $server=>$serverstats) {
						$result[$server]['version'] = $serverstats['version'];
					}
				}
			break;
		}
		return $result;
	}
}