<?php

/**
 * 文件缓存驱动
 */

namespace base\cache;

class FileCacheDriver implements CacheInterface{
    protected $config = array();

    public function __construct($config = array()) {
        $this->config = array(
            'CACHE_PATH' => 'data/caches/cache/',
            'GROUP' => 'tmp',
            'HASH_DEEP' => 0,								
        );
        $this->config = array_merge($this->config, (array)$config);
    }

    public function get($key) {
        $content = @file_get_contents( $this->_getFilePath($key) );
        if( empty($content) ) return false;

        $expire  =  (int) substr($content, 13, 12);
        if( time() >= $expire ) return false;

        $md5Sign  =  substr($content, 25, 32);
        $content   =  substr($content, 57);
        if( $md5Sign != md5($content) ) return false;

        return @unserialize($content);
    }


    public function set($key, $value, $expire = 1800) {		
        $value = serialize($value);
        $md5Sign = md5($value);
        $expire = time() + $expire;		
        $content    = '<?php exit;?>' . sprintf('%012d', $expire) . $md5Sign . $value;		

        return @file_put_contents($this->_getFilePath($key, true), $content, LOCK_EX);
    }

    public function inc($key, $value = 1) {
        return $this->set($key, intval($this->get($key)) + intval($value), -1);
    }

    public function des($key, $value = 1) {
        return $this->set($key, intval($this->get($key)) - intval($value), -1);
    }

    public function del($key) {
        return @unlink( $this->_getFilePath($key) );
    }

    public function clear( $dir='' ) {
        if( empty($dir) ) {
            $dir = $this->config['CACHE_PATH'] . '/' . $this->config['GROUP'] . '/';
            $dir = str_replace('/', DIRECTORY_SEPARATOR, $dir);
        }
        if ( !is_dir($dir) ) return false;

        $handle = opendir($dir);
        while ( ($file = readdir($handle)) !== false ){
            if ( '.' != $file && '..' != $file ){
                is_dir("$dir/$file")? $this->clear("$dir/$file") : @unlink("$dir/$file");
            }
        }
        if ( readdir($handle) == false ){
            closedir($handle);
            @rmdir($dir);
        }
    }

    private function _getFilePath($key, $isCreatePath = false) {
        $key = md5($key);

        $dir = $this->config['CACHE_PATH'] . '/' . $this->config['GROUP'] . '/';
        for($i=0; $i<$this->config['HASH_DEEP']; $i++){
            $dir = $dir. substr($key, $i*2, 2).'/';
        }
        $dir = str_replace('/', DIRECTORY_SEPARATOR, $dir);

        if ( !file_exists($dir) ) {
            if ( !@mkdir($dir, 0777, true) ){
                throw new \Exception("Can not create dir '{$dir}'", 500);
            }             
        }
        if ( !is_writable($dir) ) @chmod($dir, 0777);

        return $dir. $key . '.php';;
    }
}