<?php
/*
 +--------------------------------------------------------------------+
 | CiviCRM version 5                                                  |
 +--------------------------------------------------------------------+
 | Copyright CiviCRM LLC (c) 2004-2018                                |
 +--------------------------------------------------------------------+
 | This file is a part of CiviCRM.                                    |
 |                                                                    |
 | CiviCRM is free software; you can copy, modify, and distribute it  |
 | under the terms of the GNU Affero General Public License           |
 | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
 |                                                                    |
 | CiviCRM is distributed in the hope that it will be useful, but     |
 | WITHOUT ANY WARRANTY; without even the implied warranty of         |
 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.               |
 | See the GNU Affero General Public License for more details.        |
 |                                                                    |
 | You should have received a copy of the GNU Affero General Public   |
 | License and the CiviCRM Licensing Exception along                  |
 | with this program; if not, contact CiviCRM LLC                     |
 | at info[AT]civicrm[DOT]org. If you have questions about the        |
 | GNU Affero General Public License or the licensing of CiviCRM,     |
 | see the CiviCRM license FAQ at http://civicrm.org/licensing        |
 +--------------------------------------------------------------------+
 */

/**
 *
 * @package CRM
 * @copyright CiviCRM LLC (c) 2004-2018
 */
class CRM_Utils_Cache_Memcache implements CRM_Utils_Cache_Interface {

  use CRM_Utils_Cache_NaiveMultipleTrait; // TODO Consider native implementation.

  const DEFAULT_HOST = 'localhost';
  const DEFAULT_PORT = 11211;
  const DEFAULT_TIMEOUT = 3600;
  const DEFAULT_PREFIX = '';

  /**
   * The host name of the memcached server.
   *
   * @var string
   */
  protected $_host = self::DEFAULT_HOST;

  /**
   * The port on which to connect on.
   *
   * @var int
   */
  protected $_port = self::DEFAULT_PORT;

  /**
   * The default timeout to use.
   *
   * @var int
   */
  protected $_timeout = self::DEFAULT_TIMEOUT;

  /**
   * The prefix prepended to cache keys.
   *
   * If we are using the same memcache instance for multiple CiviCRM
   * installs, we must have a unique prefix for each install to prevent
   * the keys from clobbering each other.
   *
   * @var string
   */
  protected $_prefix = self::DEFAULT_PREFIX;

  /**
   * The actual memcache object.
   *
   * @var Memcache
   */
  protected $_cache;

  /**
   * Constructor.
   *
   * @param array $config
   *   An array of configuration params.
   *
   * @return \CRM_Utils_Cache_Memcache
   */
  public function __construct($config) {
    if (isset($config['host'])) {
      $this->_host = $config['host'];
    }
    if (isset($config['port'])) {
      $this->_port = $config['port'];
    }
    if (isset($config['timeout'])) {
      $this->_timeout = $config['timeout'];
    }
    if (isset($config['prefix'])) {
      $this->_prefix = $config['prefix'];
    }

    $this->_cache = new Memcache();

    if (!$this->_cache->connect($this->_host, $this->_port)) {
      // dont use fatal here since we can go in an infinite loop
      echo 'Could not connect to Memcached server';
      CRM_Utils_System::civiExit();
    }
  }

  /**
   * @param $key
   * @param $value
   * @param null|int|\DateInterval $ttl
   *
   * @return bool
   */
  public function set($key, $value, $ttl = NULL) {
    if ($ttl !== NULL) {
      throw new \RuntimeException("FIXME: " . __CLASS__ . "::set() should support non-NULL TTL");
    }
    if (!$this->_cache->set($this->_prefix . $key, $value, FALSE, $this->_timeout)) {
      return FALSE;
    }
    return TRUE;
  }

  /**
   * @param $key
   * @param mixed $default
   *
   * @return mixed
   */
  public function get($key, $default = NULL) {
    if ($default !== NULL) {
      throw new \RuntimeException("FIXME: " . __CLASS__ . "::get() only supports NULL default");
    }
    $result = $this->_cache->get($this->_prefix . $key);
    return $result;
  }

  /**
   * @param $key
   *
   * @return mixed
   */
  public function delete($key) {
    return $this->_cache->delete($this->_prefix . $key);
  }

  /**
   * @return bool
   */
  public function flush() {
    // FIXME: Only delete items matching `$this->_prefix`.
    return $this->_cache->flush();
  }

}