<?php
/**
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * For full copyright and license information, please see the LICENSE.txt
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @since         3.0.0
 * @license       http://www.opensource.org/licenses/mit-license.php MIT License
 */
namespace Cake\Cache;

use BadMethodCallException;
use Cake\Core\App;
use Cake\Core\ObjectRegistry;
use RuntimeException;

/**
 * An object registry for cache engines.
 *
 * Used by Cake\Cache\Cache to load and manage cache engines.
 */
class CacheRegistry extends ObjectRegistry
{

    /**
     * Resolve a cache engine classname.
     *
     * Part of the template method for Cake\Core\ObjectRegistry::load()
     *
     * @param string $class Partial classname to resolve.
     * @return string|false Either the correct classname or false.
     */
    protected function _resolveClassName($class)
    {
        if (is_object($class)) {
            return $class;
        }
        return App::className($class, 'Cache/Engine', 'Engine');
    }

    /**
     * Throws an exception when a cache engine is missing.
     *
     * Part of the template method for Cake\Core\ObjectRegistry::load()
     *
     * @param string $class The classname that is missing.
     * @param string $plugin The plugin the cache is missing in.
     * @return void
     * @throws \BadMethodCallException
     */
    protected function _throwMissingClassError($class, $plugin)
    {
        throw new BadMethodCallException(sprintf('Cache engine %s is not available.', $class));
    }

    /**
     * Create the cache engine instance.
     *
     * Part of the template method for Cake\Core\ObjectRegistry::load()
     *
     * @param string|\Cake\Cache\CacheEngine $class The classname or object to make.
     * @param string $alias The alias of the object.
     * @param array $config An array of settings to use for the cache engine.
     * @return \Cake\Cache\CacheEngine The constructed CacheEngine class.
     * @throws \RuntimeException when an object doesn't implement the correct interface.
     */
    protected function _create($class, $alias, $config)
    {
        if (is_object($class)) {
            $instance = $class;
        }

        unset($config['className']);
        if (!isset($instance)) {
            $instance = new $class($config);
        }

        if (!($instance instanceof CacheEngine)) {
            throw new RuntimeException(
                'Cache engines must use Cake\Cache\CacheEngine as a base class.'
            );
        }

        if (!$instance->init($config)) {
            throw new RuntimeException(
                sprintf('Cache engine %s is not properly configured.', get_class($instance))
            );
        }

        $config = $instance->config();
        if ($config['probability'] && time() % $config['probability'] === 0) {
            $instance->gc();
        }
        return $instance;
    }

    /**
     * Remove a single adapter from the registry.
     *
     * @param string $name The adapter name.
     * @return void
     */
    public function unload($name)
    {
        unset($this->_loaded[$name]);
    }
}
