<?php
/**
 * Part of the Joomla Framework Session Package
 *
 * @copyright  Copyright (C) 2005 - 2021 Open Source Matters, Inc. All rights reserved.
 * @license    GNU General Public License version 2 or later; see LICENSE
 */

namespace Joomla\Session\Handler;

use Joomla\Session\HandlerInterface;

/**
 * Redis session storage handler
 *
 * @since  2.0.0
 */
class RedisHandler implements HandlerInterface
{
	/**
	 * Session ID prefix to avoid naming conflicts
	 *
	 * @var    string
	 * @since  2.0.0
	 */
	private $prefix;

	/**
	 * Redis driver
	 *
	 * @var    \Redis
	 * @since  2.0.0
	 */
	private $redis;

	/**
	 * Time to live in seconds
	 *
	 * @var    integer
	 * @since  2.0.0
	 */
	private $ttl;

	/**
	 * Constructor
	 *
	 * @param   \Redis  $redis    A Redis instance
	 * @param   array   $options  Associative array of options to configure the handler
	 *
	 * @since   2.0.0
	 */
	public function __construct(\Redis $redis, array $options = [])
	{
		$this->redis = $redis;

		// Set the default time-to-live based on the Session object's default configuration
		$this->ttl = isset($options['ttl']) ? (int) $options['ttl'] : 900;

		// Namespace our session IDs to avoid potential conflicts
		$this->prefix = $options['prefix'] ?? 'jfw';
	}

	/**
	 * Close the session
	 *
	 * @return  boolean  True on success, false otherwise
	 *
	 * @since   2.0.0
	 */
	public function close()
	{
		// No need to close the connection to Redis server manually.
		return true;
	}

	/**
	 * Destroy a session, called automatically when running session_regenerate_id().
	 *
	 * @param   integer  $session_id  The session ID being destroyed
	 *
	 * @return  boolean  True on success, false otherwise
	 *
	 * @since   2.0.0
	 */
	public function destroy($session_id): bool
	{
		$this->redis->del($this->prefix . $session_id);

		// Session callback must have a return value of type bool when session_regenerate_id() is called.
		return true;
	}

	/**
	 * Cleanup old sessions
	 *
	 * @param   integer  $maxlifetime  Sessions that have not updated for the last maxlifetime seconds will be removed
	 *
	 * @return  boolean  True on success, false otherwise
	 *
	 * @since   2.0.0
	 */
	public function gc($maxlifetime)
	{
		return true;
	}

	/**
	 * Test to see if the HandlerInterface is available
	 *
	 * @return  boolean  True on success, false otherwise
	 *
	 * @since   2.0.0
	 */
	public static function isSupported(): bool
	{
		return \extension_loaded('redis') && class_exists('Redis');
	}

	/**
	 * Initialize session
	 *
	 * @param   string  $save_path   The path where to store/retrieve the session
	 * @param   string  $session_id  The session id
	 *
	 * @return  boolean  True on success, false otherwise
	 *
	 * @since   2.0.0
	 */
	public function open($save_path, $session_id)
	{
		return true;
	}

	/**
	 * Read session data
	 *
	 * @param   string  $session_id  The session id to read data for
	 *
	 * @return  string  The session data
	 *
	 * @since   2.0.0
	 */
	public function read($session_id)
	{
		return $this->redis->get($this->prefix . $session_id) ?: '';
	}

	/**
	 * Write session data
	 *
	 * @param   string  $session_id    The session id
	 * @param   string  $session_data  The encoded session data
	 *
	 * @return  boolean  True on success, false otherwise
	 *
	 * @since   2.0.0
	 */
	public function write($session_id, $session_data)
	{
		if ($this->ttl > 0)
		{
			return $this->redis->setex($this->prefix . $session_id, $this->ttl, $session_data);
		}

		return $this->redis->set($this->prefix . $session_id, $session_data);
	}
}
