<?php
/*
* 2007-2015 PrestaShop
*
* NOTICE OF LICENSE
*
* This source file is subject to the Open Software License (OSL 3.0)
* that is bundled with this package in the file LICENSE.txt.
* It is also available through the world-wide-web at this URL:
* http://opensource.org/licenses/osl-3.0.php
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to license@prestashop.com so we can send you a copy immediately.
*
* DISCLAIMER
*
* Do not edit or add to this file if you wish to upgrade PrestaShop to newer
* versions in the future. If you wish to customize PrestaShop for your
* needs please refer to http://www.prestashop.com for more information.
*
*  @author PrestaShop SA <contact@prestashop.com>
*  @copyright  2007-2015 PrestaShop SA
*  @license    http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
*  International Registered Trademark & Property of PrestaShop SA
*/

/**
 * This class require PECL Memcache extension
 *
 */
class CacheMemcacheCore extends Cache
{
	/**
	 * @var Memcache
	 */
	protected $memcache;

	/**
	 * @var bool Connection status
	 */
	protected $is_connected = false;

	public function __construct()
	{
		$this->connect();
	}

	public function __destruct()
	{
		$this->close();
	}

	/**
	 * Connect to memcache server
	 */
	public function connect()
	{
		if (class_exists('Memcache') && extension_loaded('memcache'))
			$this->memcache = new Memcache();
		else
			return;

		$servers = self::getMemcachedServers();
		if (!$servers)
			return;
		foreach ($servers as $server)
			$this->memcache->addServer($server['ip'], $server['port'], true, (int)$server['weight']);

		$this->is_connected = true;
	}

	/**
	 * @see Cache::_set()
	 */
	protected function _set($key, $value, $ttl = 0)
	{
		if (!$this->is_connected)
			return false;
		return $this->memcache->set($key, $value, 0, $ttl);
	}

	/**
	 * @see Cache::_get()
	 */
	protected function _get($key)
	{
		if (!$this->is_connected)
			return false;
		return $this->memcache->get($key);
	}

	/**
	 * @see Cache::_exists()
	 */
	protected function _exists($key)
	{
		if (!$this->is_connected)
			return false;
		return ($this->memcache->get($key) !== false);
	}

	/**
	 * @see Cache::_delete()
	 */
	protected function _delete($key)
	{
		if (!$this->is_connected)
			return false;
		return $this->memcache->delete($key);
	}

	/**
	 * @see Cache::_writeKeys()
	 */
	protected function _writeKeys()
	{
		if (!$this->is_connected)
			return false;
		return true;
	}

	/**
	 * @see Cache::flush()
	 */
	public function flush()
	{
		if (!$this->is_connected)
			return false;
		return $this->memcache->flush();
	}

	/**
	 * Store a data in cache
	 *
	 * @param string $key
	 * @param mixed $value
	 * @param int $ttl
	 * @return bool
	 */
	public function set($key, $value, $ttl = 0)
	{
		return $this->_set($key, $value, $ttl);
	}

	/**
	 * Retrieve a data from cache
	 *
	 * @param string $key
	 * @return mixed
	 */
	public function get($key)
	{
		return $this->_get($key);
	}

	/**
	 * Check if a data is cached
	 *
	 * @param string $key
	 * @return bool
	 */
	public function exists($key)
	{
		return $this->_exists($key);
	}

	/**
	 * Delete one or several data from cache (* joker can be used, but avoid it !)
	 * 	E.g.: delete('*'); delete('my_prefix_*'); delete('my_key_name');
	 *
	 * @param string $key
	 * @return bool
	 */
	public function delete($key)
	{
		if ($key == '*')
			$this->flush();
		elseif (strpos($key, '*') === false)
			$this->_delete($key);
		else
		{
			// Get keys (this code comes from Doctrine 2 project)
			$pattern = str_replace('\\*', '.*', preg_quote($key));
			$servers = $this->getMemcachedServers();
			if (is_array($servers) && count($servers) > 0 && method_exists('Memcache', 'getStats'))
				$all_slabs = $this->memcache->getStats('slabs');

			if (isset($all_slabs) && is_array($all_slabs))
			{
				foreach ($all_slabs as $server => $slabs)
				{
					if (is_array($slabs))
					{
						foreach (array_keys($slabs) as $i => $slab_id) // $slab_id is not an int but a string, using the key instead ?
						{
							if (is_int($i))
							{
								$dump = $this->memcache->getStats('cachedump', (int)$i);
								if ($dump)
								{
									foreach ($dump as $entries)
									{
										if ($entries)
										{
											foreach ($entries as $key => $data)
											{
												if (preg_match('#^'.$pattern.'$#', $key))
													$this->_delete($key);
											}
										}
									}
								}
							}
						}
					}
				}
			}
		}
		return true;
	}

	/**
	 * Close connection to memcache server
	 *
	 * @return bool
	 */
	protected function close()
	{
		if (!$this->is_connected)
			return false;
		return $this->memcache->close();
	}

	/**
	 * Add a memcache server
	 *
	 * @param string $ip
	 * @param int $port
	 * @param int $weight
	 */
	public static function addServer($ip, $port, $weight)
	{
		return Db::getInstance()->execute('INSERT INTO '._DB_PREFIX_.'memcached_servers (ip, port, weight) VALUES(\''.pSQL($ip).'\', '.(int)$port.', '.(int)$weight.')', false);
	}

	/**
	 * Get list of memcached servers
	 *
	 * @return array
	 */
	public static function getMemcachedServers()
	{
		return Db::getInstance(_PS_USE_SQL_SLAVE_)->executeS('SELECT * FROM '._DB_PREFIX_.'memcached_servers', true, false);
	}

	/**
	 * Delete a memcache server
	 *
	 * @param int $id_server
	 */
	public static function deleteServer($id_server)
	{
		return Db::getInstance()->execute('DELETE FROM '._DB_PREFIX_.'memcached_servers WHERE id_memcached_server='.(int)$id_server);
	}
}