<?php

/**
 * @package KantPHP
 * @author  Zhenqiang Zhang <zhenqiang.zhang@hotmail.com>
 * @copyright (c) KantPHP Studio, All rights reserved.
 * @license http://www.opensource.org/licenses/BSD-3-Clause  The BSD 3-Clause License
 */
namespace Kant\Caching;

/**
 * ArrayCache provides caching for the current request only by storing the values in an array.
 *
 * See [[Cache]] for common cache operations that ArrayCache supports.
 *
 * Unlike the [[Cache]], ArrayCache allows the expire parameter of [[set]], [[add]], [[multiSet]] and [[multiAdd]] to
 * be a floating point number, so you may specify the time in milliseconds (e.g. 0.1 will be 100 milliseconds).
 *
 * For enhanced performance of ArrayCache, you can disable serialization of the stored data by setting [[$serializer]] to `false`.
 *
 * For more details and usage information on Cache, see the [guide article on caching](guide:caching-overview).
 *
 * @author Carsten Brandt <mail@cebe.cc>
 * @since 2.0
 */
class ArrayCache extends Cache
{

    private $_cache;

    /**
     * @inheritdoc
     */
    public function exists($key)
    {
        $key = $this->buildKey($key);
        return isset($this->_cache[$key]) && ($this->_cache[$key][1] === 0 || $this->_cache[$key][1] > microtime(true));
    }

    /**
     * @inheritdoc
     */
    protected function getValue($key)
    {
        if (isset($this->_cache[$key]) && ($this->_cache[$key][1] === 0 || $this->_cache[$key][1] > microtime(true))) {
            return $this->_cache[$key][0];
        }
        return false;
    }

    /**
     * @inheritdoc
     */
    protected function setValue($key, $value, $duration)
    {
        $this->_cache[$key] = [
            $value,
            $duration === 0 ? 0 : microtime(true) + $duration
        ];
        return true;
    }

    /**
     * @inheritdoc
     */
    protected function addValue($key, $value, $duration)
    {
        if (isset($this->_cache[$key]) && ($this->_cache[$key][1] === 0 || $this->_cache[$key][1] > microtime(true))) {
            return false;
        }
        $this->_cache[$key] = [
            $value,
            $duration === 0 ? 0 : microtime(true) + $duration
        ];
        return true;
    }

    /**
     * @inheritdoc
     */
    protected function deleteValue($key)
    {
        unset($this->_cache[$key]);
        return true;
    }

    /**
     * @inheritdoc
     */
    protected function flushValues()
    {
        $this->_cache = [];
        return true;
    }
}
