<?php

// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006-2012 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------

/**
 * 文件类型缓存类.
 *
 * @category   Think
 *
 * @author    liu21st <liu21st@gmail.com>
 */
class CacheFile extends Cache
{
    /**
     * 架构函数.
     */
    public function __construct($options = array())
    {
        if (!empty($options)) {
            $this->options = $options;
        }
        $this->options['temp'] = !empty($options['temp']) ? $options['temp'] : C('DATA_CACHE_PATH');
        $this->options['prefix'] = isset($options['prefix']) ? $options['prefix'] : C('DATA_CACHE_PREFIX');
        $this->options['expire'] = isset($options['expire']) ? $options['expire'] : C('DATA_CACHE_TIME');
        $this->options['length'] = isset($options['length']) ? $options['length'] : 0;
        if (substr($this->options['temp'], -1) != '/') {
            $this->options['temp'] .= '/';
        }
    }

    /**
     * 取得变量的存储文件名.
     *
     * @param string $name 缓存变量名
     *
     * @return string
     */
    private function filename($name)
    {
        $name = md5($name);
        if (C('DATA_CACHE_SUBDIR')) {
            // 使用子目录
            $dir = '';
            for ($i = 0; $i < C('DATA_PATH_LEVEL'); $i++) {
                $dir .= $name[$i]
                .'/';
            }
            if (!is_dir($this->options['temp'].$dir)) {
                \Medz\Component\Filesystem\Filesystem::mkdir($this->options['temp'].$dir, 0777);
            }
            $filename = $dir.$this->options['prefix'].$name.'.php';
        } else {
            $filename = $this->options['prefix'].$name.'.php';
        }

        return $this->options['temp'].$filename;
    }

    /**
     * 读取缓存.
     *
     * @param string $name 缓存变量名
     *
     * @return mixed
     */
    public function get($name)
    {
        $filename = $this->filename($name);
        if (!is_file($filename)) {
            return false;
        }
        N('cache_read', 1);
        $content = file_get_contents($filename);
        if (false !== $content) {
            $expire = (int) substr($content, 8, 12);
            if ($expire != 0 && time() > filemtime($filename) + $expire) {
                //缓存过期删除缓存文件
                unlink($filename);

                return false;
            }
            if (C('DATA_CACHE_CHECK')) {
                //开启数据校验
                $check = substr($content, 20, 32);
                $content = substr($content, 52, -3);
                if ($check != md5($content)) {
                    //校验错误
                    return false;
                }
            } else {
                $content = substr($content, 20, -3);
            }
            if (C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {
                //启用数据压缩
                $content = gzuncompress($content);
            }
            $content = unserialize($content);

            return $content;
        } else {
            return false;
        }
    }

    /**
     * 写入缓存.
     *
     * @param string $name   缓存变量名
     * @param mixed  $value  存储数据
     * @param int    $expire 有效时间 0为永久
     *
     * @return boolen
     */
    public function set($name, $value, $expire = null)
    {
        N('cache_write', 1);
        if (is_null($expire)) {
            $expire = $this->options['expire'];
        }
        $filename = $this->filename($name);
        $data = serialize($value);
        if (C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {
            //数据压缩
            $data = gzcompress($data, 3);
        }
        if (C('DATA_CACHE_CHECK')) {
            //开启数据校验
            $check = md5($data);
        } else {
            $check = '';
        }
        $data = "<?php\n//".sprintf('%012d', $expire).$check.$data."\n?>";
        $result = file_put_contents($filename, $data);
        if ($result) {
            if ($this->options['length'] > 0) {
                // 记录缓存队列
                $this->queue($name);
            }
            clearstatcache();

            return true;
        } else {
            return false;
        }
    }

    /**
     * 删除缓存.
     *
     * @param string $name 缓存变量名
     *
     * @return boolen
     */
    public function rm($name)
    {
        if (file_exists($this->filename($name))) {
            return unlink($this->filename($name));
        }
    }

    /**
     * 清除缓存.
     *
     * @param string $name 缓存变量名
     *
     * @return boolen
     */
    public function clear()
    {
        $path = $this->options['temp'];
        if ($dir = opendir($path)) {
            while ($file = readdir($dir)) {
                $check = is_dir($file);
                if (!$check) {
                    unlink($path.$file);
                }
            }
            closedir($dir);

            return true;
        }
    }
}
