<?php declare(strict_types=1);
/**
 * Banker
 *
 * A Caching library implementing psr/cache
 *
 * PHP version 7.1
 *
 * @package     Banker
 * @author      Timothy J. Warren <tim@timshomepage.net>
 * @copyright   2016 - 2018  Timothy J. Warren
 * @license     http://www.opensource.org/licenses/mit-license.html  MIT License
 * @version     2.0.0
 * @link        https://git.timshomepage.net/timw4mail/banker
 */
namespace Aviat\Banker\Driver;

use function apcu_add;
use function apcu_clear_cache;
use function apcu_delete;
use function apcu_exists;
use function apcu_fetch;
use function apcu_store;

use Aviat\Banker\Exception\CacheException;


/**
 * Memcached cache backend
 */
class ApcuDriver extends AbstractDriver {

	/**
	 * Constructor
	 *
	 * @param array $config - Not used by this driver
	 * @param array $options - Not used by this driver
	 */
	public function __construct(array $config = [], array $options = [])
	{
		// noop
	}

	/**
	 * Destructor
	 */
	public function __destruct()
	{
		// noop
	}

	/**
	 * See if a key currently exists in the cache
	 *
	 * @param string $key
	 * @return bool
	 */
	public function exists(string $key): bool
	{
		return apcu_exists($key) !== FALSE;
	}

	/**
	 * Get the value for the selected cache key
	 *
	 * @param string $key
	 * @return mixed
	 */
	public function get(string $key)
	{
		return apcu_fetch($key);
	}

	/**
	 * Retrieve a set of values by their cache key
	 *
	 * @param string[] $keys
	 * @return array
	 */
	public function getMultiple(array $keys = []): array
	{
		$status = FALSE;
		return apcu_fetch($keys, $status);
	}

	/**
	 * Set a cached value
	 *
	 * @param string $key
	 * @param mixed $value
	 * @param int $expires
	 * @return DriverInterface
	 */
	public function set(string $key, $value, int $expires = 0): DriverInterface
	{
		if ( ! apcu_exists($key))
		{
			apcu_add($key, $value, $expires);
		}
		else
		{
			apcu_store($key, $value, $expires);
		}

		return $this;
	}

	/**
	 * Remove an item from the cache
	 *
	 * @param string $key
	 * @return boolean
	 */
	public function delete(string $key): bool
	{
		return (bool) apcu_delete($key);
	}

	/**
	 * Remove multiple items from the cache
	 *
	 * @param string[] $keys
	 * @return boolean
	 */
	public function deleteMultiple(array $keys = []): bool
	{
		return (bool) apcu_delete($keys);
	}

	/**
	 * Empty the cache
	 *
	 * @return boolean
	 */
	public function flush(): bool
	{
		return apcu_clear_cache();
	}

	/**
	 * Set the specified key to expire at the given time
	 *
	 * @param string $key
	 * @param int $expires
	 * @return boolean
	 */
	public function expiresAt(string $key, int $expires): bool
	{
		if ($this->exists($key))
		{
			$value = $this->get($key);
			return apcu_store($key, $value, $expires);
		}

		$this->getLogger()->log('warning', 'Tried to set expiration on a key that does not exist');

		return FALSE;
	}
}