<?php
namespace wxapp\pay;

class WeixinRefund {
    //证书目录
    protected $SSLCERT_PATH;
    protected $SSLKEY_PATH;
    protected $appid;
    protected $mchid;
    protected $key;
    protected $openid;
    protected $outTradeNo;
    protected $totalFee;
    protected $outRefundNo;
    protected $refundFee;

    function __construct(){
        //初始化退款类需要的变量
        $this->appid = config('app_id');
        $this->mchid = config('wx_mch_id');
        $this->key = config('wx_pay_key');
        $this->SSLCERT_PATH = config('cert_path');
        $this->SSLKEY_PATH = config('key_path');
    }
    public function refund($openid,$outTradeNo,$totalFee,$outRefundNo,$refundFee){
        $this->openid = $openid;
        $this->outTradeNo = $outTradeNo;
        $this->totalFee = $totalFee;
        $this->outRefundNo = $outRefundNo;
        $this->refundFee = $refundFee;
        //对外暴露的退款接口
        $result = $this->wxrefundapi();
        return $result;
    }
    private function wxrefundapi(){
        //通过微信api进行退款流程
        $parma = array(
            'appid'=> $this->appid,
            'mch_id'=> $this->mchid,
            'nonce_str'=> $this->createNoncestr(),
            'out_refund_no'=> $this->outRefundNo,//退款订单号
            'out_trade_no'=> $this->outTradeNo,//商户订单号
            'total_fee'=> $this->totalFee*100,//订单总金额
            'refund_fee'=> $this->refundFee*100,//申请退款金额
        );
        $parma['sign'] = $this->getSign($parma);
        $xmldata = $this->arrayToXml($parma);
        $xmlresult = $this->postXmlSSLCurl($xmldata,'https://api.mch.weixin.qq.com/secapi/pay/refund');
        $result = $this->xmlToArray($xmlresult);
        return $result;
    }
    //作用：产生随机字符串，不长于32位
    private function createNoncestr($length = 32) {
        $chars = "abcdefghijklmnopqrstuvwxyz0123456789";
        $str = "";
        for ($i = 0; $i < $length; $i++) {
            $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
        }
        return $str;
    }
    //作用：生成签名
    private function getSign($Obj) {
        foreach ($Obj as $k => $v) {
            $Parameters[$k] = $v;
        }
        //签名步骤一：按字典序排序参数
        ksort($Parameters);
        $String = $this->formatBizQueryParaMap($Parameters, false);
        //签名步骤二：在string后加入KEY
        $String = $String . "&key=" . $this->key;
        //签名步骤三：MD5加密
        $String = md5($String);
        //签名步骤四：所有字符转为大写
        $result_ = strtoupper($String);
        return $result_;
    }
    //数组转换成xml
    private function arrayToXml($arr) {
        $xml = "<root>";
        foreach ($arr as $key => $val) {
            if (is_array($val)) {
                $xml .= "<" . $key . ">" . arrayToXml($val) . "</" . $key . ">";
            } else {
                $xml .= "<" . $key . ">" . $val . "</" . $key . ">";
            }
        }
        $xml .= "</root>";
        return $xml;
    }
    //xml转换成数组
    private function xmlToArray($xml) {
        //禁止引用外部xml实体
        libxml_disable_entity_loader(true);
        $xmlstring = simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA);
        $val = json_decode(json_encode($xmlstring), true);
        return $val;
    }
    //需要使用证书的请求
    function postXmlSSLCurl($xml,$url,$second=30){
        $ch = curl_init();
        //超时时间
        curl_setopt($ch,CURLOPT_TIMEOUT,$second);
        //这里设置代理，如果有的话
        //curl_setopt($ch,CURLOPT_PROXY, '8.8.8.8');
        //curl_setopt($ch,CURLOPT_PROXYPORT, 8080);
        curl_setopt($ch,CURLOPT_URL, $url);
        curl_setopt($ch,CURLOPT_SSL_VERIFYPEER,FALSE);
        curl_setopt($ch,CURLOPT_SSL_VERIFYHOST,FALSE);
        //设置header
        curl_setopt($ch,CURLOPT_HEADER,FALSE);
        //要求结果为字符串且输出到屏幕上
        curl_setopt($ch,CURLOPT_RETURNTRANSFER,TRUE);
        //设置证书
        //使用证书：cert 与 key 分别属于两个.pem文件
        //默认格式为PEM，可以注释
        curl_setopt($ch,CURLOPT_SSLCERTTYPE,'PEM');
        curl_setopt($ch,CURLOPT_SSLCERT, $this->SSLCERT_PATH);
        //默认格式为PEM，可以注释
        curl_setopt($ch,CURLOPT_SSLKEYTYPE,'PEM');
        curl_setopt($ch,CURLOPT_SSLKEY, $this->SSLKEY_PATH);
        //post提交方式
        curl_setopt($ch,CURLOPT_POST, true);
        curl_setopt($ch,CURLOPT_POSTFIELDS,$xml);
        $data = curl_exec($ch);
        //返回结果
        if($data){
            curl_close($ch);
            return $data;
        } else {
            $error = curl_errno($ch);
            echo "curl出错，错误码:$error"."<br>";
            curl_close($ch);
            return false;
        }
    }
    ///作用：格式化参数，签名过程需要使用
    private function formatBizQueryParaMap($paraMap, $urlencode) {
        $buff = "";
        ksort($paraMap);
        foreach ($paraMap as $k => $v) {
            if ($urlencode) {
                $v = urlencode($v);
            }
            $buff .= $k . "=" . $v . "&";
        }
        $reqPar = '';
        if (strlen($buff) > 0) {
            $reqPar = substr($buff, 0, strlen($buff) - 1);
        }
        return $reqPar;
    }
}