<?php

/**
 * User lin
 * Class Patch
 * @package helper
 */
class Patch
{

    // 签名
    public static function sign($param, $key)
    {
        try{
            if(isset($param['sign'])) unset($param['sign']);
            ksort($param);
            $stringA = '';
            foreach ($param as $k=>$v){
                $stringA .= $k.'='.urlencode($v).'&';
            }
            $stringA .= 'key='.$key;
            $sign = base64_encode(md5($stringA));
            return $sign;
        }catch (\Exception $e){
            return false;
        }
    }

    // 验签并返回解析结果
    public static function checkSign($stream, $key)
    {
        try{
            if(!$stream) return false;
            $json = base64_decode($stream);
            $param = json_decode($json, true);
            $stream_sign = $param['sign'];
            $sign = self::sign($param, $key);
            if($sign != $stream_sign) return false;
            return $param;
        }catch (\Exception $e){
            return false;
        }
    }

    // 打补丁
    public static function packPatch($name, $desc, $exec, $ver, $key)
    {
        $param = [];
        // 补丁名称
        $param['name'] = $name;
        // 补丁描述
        $param['desc'] = $desc;
        // 补丁适用版本，适用于在此版本之前的版本升级到此版本时使用
        $param['ver'] = $ver;
        // 补丁发行日期
        $param['date'] = date('Y-m-d H:i:s');
        // 补丁代码 - php
        $param['exec'] = self::packExec($exec);
        // 签名
        $param['sign'] = self::sign($param, $key);
        return base64_encode(json_encode($param));
    }

    // 编码补丁代码
    private static function packExec($exec)
    {
        $stringA = urlencode(htmlspecialchars($exec));
        $stringB = base64_encode($stringA);
        return $stringB;
    }

    // 解码补丁代码
    public static function unpackExec($exec)
    {
        $stringA = base64_decode($exec);
        $stringB = htmlspecialchars_decode(urldecode($stringA));
        return $stringB;
    }

}