<?php

/**
 * Joomla! Content Management System
 *
 * @copyright  (C) 2016 Open Source Matters, Inc. <https://www.joomla.org>
 * @license    GNU General Public License version 2 or later; see LICENSE.txt
 */

namespace Joomla\CMS\Cache\Storage;

use Joomla\CMS\Cache\CacheStorage;

// phpcs:disable PSR1.Files.SideEffects
\defined('_JEXEC') or die;
// phpcs:enable PSR1.Files.SideEffects

/**
 * APCu cache storage handler
 *
 * @link   https://www.php.net/manual/en/ref.apcu.php
 * @since  3.5
 */
class ApcuStorage extends CacheStorage
{
    /**
     * Check if the cache contains data stored by ID and group
     *
     * @param   string  $id     The cache data ID
     * @param   string  $group  The cache data group
     *
     * @return  boolean
     *
     * @since   3.7.0
     */
    public function contains($id, $group)
    {
        return apcu_exists($this->_getCacheId($id, $group));
    }

    /**
     * Get cached data by ID and group
     *
     * @param   string   $id         The cache data ID
     * @param   string   $group      The cache data group
     * @param   boolean  $checkTime  True to verify cache time expiration threshold
     *
     * @return  mixed  Boolean false on failure or a cached data object
     *
     * @since   3.5
     */
    public function get($id, $group, $checkTime = true)
    {
        return apcu_fetch($this->_getCacheId($id, $group));
    }

    /**
     * Get all cached data
     *
     * @return  mixed  Boolean false on failure or a cached data object
     *
     * @since   3.5
     */
    public function getAll()
    {
        $allinfo = apcu_cache_info();
        $keys    = $allinfo['cache_list'];
        $secret  = $this->_hash;

        $data = [];

        foreach ($keys as $key) {
            if (isset($key['info'])) {
                // The internal key name changed with APCu 4.0.7 from key to info
                $name = $key['info'];
            } elseif (isset($key['entry_name'])) {
                // Some APCu modules changed the internal key name from key to entry_name
                $name = $key['entry_name'];
            } else {
                // A fall back for the old internal key name
                $name = $key['key'];
            }

            $namearr = explode('-', $name);

            if ($namearr !== false && $namearr[0] == $secret && $namearr[1] === 'cache') {
                $group = $namearr[2];

                if (!isset($data[$group])) {
                    $item = new CacheStorageHelper($group);
                } else {
                    $item = $data[$group];
                }

                $item->updateSize($key['mem_size']);

                $data[$group] = $item;
            }
        }

        return $data;
    }

    /**
     * Store the data to cache by ID and group
     *
     * @param   string  $id     The cache data ID
     * @param   string  $group  The cache data group
     * @param   string  $data   The data to store in cache
     *
     * @return  boolean
     *
     * @since   3.5
     */
    public function store($id, $group, $data)
    {
        return apcu_store($this->_getCacheId($id, $group), $data, $this->_lifetime);
    }

    /**
     * Remove a cached data entry by ID and group
     *
     * @param   string  $id     The cache data ID
     * @param   string  $group  The cache data group
     *
     * @return  boolean
     *
     * @since   3.5
     */
    public function remove($id, $group)
    {
        $cache_id = $this->_getCacheId($id, $group);

        // The apcu_delete function returns false if the ID does not exist
        if (apcu_exists($cache_id)) {
            return apcu_delete($cache_id);
        }

        return true;
    }

    /**
     * Clean cache for a group given a mode.
     *
     * group mode    : cleans all cache in the group
     * notgroup mode : cleans all cache not in the group
     *
     * @param   string  $group  The cache data group
     * @param   string  $mode   The mode for cleaning cache [group|notgroup]
     *
     * @return  boolean
     *
     * @since   3.5
     */
    public function clean($group, $mode = null)
    {
        $allinfo = apcu_cache_info();
        $keys    = $allinfo['cache_list'];
        $secret  = $this->_hash;

        foreach ($keys as $key) {
            if (isset($key['info'])) {
                // The internal key name changed with APCu 4.0.7 from key to info
                $internalKey = $key['info'];
            } elseif (isset($key['entry_name'])) {
                // Some APCu modules changed the internal key name from key to entry_name
                $internalKey = $key['entry_name'];
            } else {
                // A fall back for the old internal key name
                $internalKey = $key['key'];
            }

            if (strpos($internalKey, $secret . '-cache-' . $group . '-') === 0 xor $mode !== 'group') {
                apcu_delete($internalKey);
            }
        }

        return true;
    }

    /**
     * Garbage collect expired cache data
     *
     * @return  boolean
     *
     * @since   3.5
     */
    public function gc()
    {
        $allinfo = apcu_cache_info();
        $keys    = $allinfo['cache_list'];
        $secret  = $this->_hash;

        foreach ($keys as $key) {
            if (isset($key['info'])) {
                // The internal key name changed with APCu 4.0.7 from key to info
                $internalKey = $key['info'];
            } elseif (isset($key['entry_name'])) {
                // Some APCu modules changed the internal key name from key to entry_name
                $internalKey = $key['entry_name'];
            } else {
                // A fall back for the old internal key name
                $internalKey = $key['key'];
            }

            if (strpos($internalKey, $secret . '-cache-')) {
                apcu_fetch($internalKey);
            }
        }

        return true;
    }

    /**
     * Test to see if the storage handler is available.
     *
     * @return  boolean
     *
     * @since   3.5
     */
    public static function isSupported()
    {
        $supported = \extension_loaded('apcu') && ini_get('apc.enabled');

        // If on the CLI interface, the `apc.enable_cli` option must also be enabled
        if ($supported && PHP_SAPI === 'cli') {
            $supported = ini_get('apc.enable_cli');
        }

        return (bool) $supported;
    }

    /**
     * Lock cached item
     *
     * @param   string   $id        The cache data ID
     * @param   string   $group     The cache data group
     * @param   integer  $locktime  Cached item max lock time
     *
     * @return  mixed  Boolean false if locking failed or an object containing properties lock and locklooped
     *
     * @since   3.5
     */
    public function lock($id, $group, $locktime)
    {
        $returning             = new \stdClass();
        $returning->locklooped = false;

        $looptime = $locktime * 10;

        $cache_id = $this->_getCacheId($id, $group) . '_lock';

        $data_lock = apcu_add($cache_id, 1, $locktime);

        if ($data_lock === false) {
            $lock_counter = 0;

            // Loop until you find that the lock has been released.
            // That implies that data get from other thread has finished
            while ($data_lock === false) {
                if ($lock_counter > $looptime) {
                    $returning->locked     = false;
                    $returning->locklooped = true;
                    break;
                }

                usleep(100);
                $data_lock = apcu_add($cache_id, 1, $locktime);
                $lock_counter++;
            }
        }

        $returning->locked = $data_lock;

        return $returning;
    }

    /**
     * Unlock cached item
     *
     * @param   string  $id     The cache data ID
     * @param   string  $group  The cache data group
     *
     * @return  boolean
     *
     * @since   3.5
     */
    public function unlock($id, $group = null)
    {
        $cache_id = $this->_getCacheId($id, $group) . '_lock';

        // The apcu_delete function returns false if the ID does not exist
        if (apcu_exists($cache_id)) {
            return apcu_delete($cache_id);
        }

        return true;
    }
}
