wechat v3 refund (#101)

* refund

* Update pay_public_api.go

Co-authored-by: cr <cr>

wechat/v3/model.go

@@ -39,6 +39,7 @@ const (
 	v3CombineNative   = "/v3/combine-transactions/native"
 	v3CombineQuery    = "/v3/combine-transactions/out-trade-no/%s"
 	v3CombineClose    = "/v3/combine-transactions/out-trade-no/%s/close"
+	v3Refund          = "/v3/refund/domestic/refunds"
 
 	// 微信支付分
 	v3ScorePermission                       = "/v3/payscore/permissions"                                 // 商户预授权 POST
@@ -133,6 +134,14 @@ type CloseOrderRsp struct {
 	Error    string    `json:"-"`
 }
 
+// 退款 Rsp
+type RefundRsp struct {
+	Code     int                  `json:"-"`
+	SignInfo *SignInfo            `json:"-"`
+	Response *RefundOrderResponse `json:"response,omitempty"`
+	Error    string               `json:"-"`
+}
+
 // 交易、资金账单 Rsp
 type BillRsp struct {
 	Code     int        `json:"-"`
@@ -243,6 +252,7 @@ type Amount struct {
 	PayerTotal    int    `json:"payer_total,omitempty"`    // 用户支付金额，单位为分
 	Currency      string `json:"currency,omitempty"`       // CNY：人民币，境内商户号仅支持人民币
 	PayerCurrency string `json:"payer_currency,omitempty"` // 用户支付币种
+	Refund        int    `json:"refund,omitempty"`         // 退款金额，币种的最小单位，只能为整数，不能超过原订单支付金额。
 }
 
 type CombineAmount struct {
@@ -271,11 +281,12 @@ type PromotionDetail struct {
 }
 
 type GoodsDetail struct {
-	GoodsId        string `json:"goods_id"`               // 商品编码
-	Quantity       int    `json:"quantity"`               // 用户购买的数量
-	UnitPrice      int    `json:"unit_price"`             // 商品单价，单位为分
-	DiscountAmount int    `json:"discount_amount"`        // 商品优惠金额
-	GoodsRemark    string `json:"goods_remark,omitempty"` // 商品备注信息
+	GoodsId         string `json:"goods_id"`                    // 商品编码
+	Quantity        int    `json:"quantity"`                    // 用户购买的数量
+	UnitPrice       int    `json:"unit_price"`                  // 商品单价，单位为分
+	DiscountAmount  int    `json:"discount_amount"`             // 商品优惠金额
+	GoodsRemark     string `json:"goods_remark,omitempty"`      // 商品备注信息
+	MerchantGoodsID string `json:"merchant_goods_id,omitempty"` // 商户侧商品编码
 }
 
 type QueryOrder struct {
@@ -337,3 +348,18 @@ type DownloadBill struct {
 	DownloadBillCount int           `json:"download_bill_count"`
 	DownloadBillList  []*BillDetail `json:"download_bill_list"`
 }
+
+type RefundOrderResponse struct {
+	RefundID            string             `json:"refund_id" valid:"Required"`             // 微信支付退款号
+	OutRefundNo         string             `json:"out_refund_no" valid:"Required"`         // 商户退款单号
+	TransactionID       string             `json:"transaction_id" valid:"Required"`        // 微信支付系统生成的订单号
+	OutTradeNo          string             `json:"out_trade_no" valid:"Required"`          // 商户系统内部订单号，只能是数字、大小写字母_-*且在同一个商户号下唯一
+	Channel             string             `json:"channel" valid:"Required"`               // 退款渠道
+	UserReceivedAccount string             `json:"user_received_account" valid:"Required"` // 退款入账账户
+	SuccessTime         string             `json:"success_time"`                           // 退款成功时间
+	CreateTime          string             `json:"create_time" valid:"Required"`           // 退款创建时间
+	Status              string             `json:"status" valid:"Required"`                // 退款状态
+	FundsAccount        string             `json:"funds_account"`                          // 资金账户
+	Amount              *Amount            `json:"amount" valid:"Required"`                // 金额信息
+	PromotionDetail     []*PromotionDetail `json:"promotion_detail"`                       // 优惠退款信息
+}

wechat/v3/pay_public_api.go

@@ -580,3 +580,34 @@ func (c *ClientV3) V3CombineTransactionCloseOrder(tradeNo string, bm gopay.BodyM
 	}
 	return wxRsp, c.verifySyncSign(si)
 }
+
+// 申请退款API
+//	Code = 0 is success
+//	文档：https://pay.weixin.qq.com/wiki/doc/apiv3/apis/chapter5_1_14.shtml
+func (c *ClientV3) V3Refund(bm gopay.BodyMap) (wxRsp *RefundRsp, err error) {
+	var (
+		ts       = time.Now().Unix()
+		nonceStr = util.GetRandomString(32)
+		url      = v3Refund
+	)
+	authorization, err := c.authorization(MethodPost, url, nonceStr, ts, bm)
+	if err != nil {
+		return nil, err
+	}
+	res, si, bs, err := c.doProdPost(bm, url, authorization)
+	if err != nil {
+		return nil, err
+	}
+
+	wxRsp = &RefundRsp{Code: Success, SignInfo: si}
+	wxRsp.Response = new(RefundOrderResponse)
+	if err = json.Unmarshal(bs, wxRsp.Response); err != nil {
+		return nil, fmt.Errorf("json.Unmarshal(%s)：%w", string(bs), err)
+	}
+	if res.StatusCode != http.StatusOK {
+		wxRsp.Code = res.StatusCode
+		wxRsp.Error = string(bs)
+		return wxRsp, nil
+	}
+	return wxRsp, c.verifySyncSign(si)
+}