/*
   Copyright 2020 XiaochengTech

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package wxpay

import (
	"encoding/xml"
	"errors"

	"github.com/beevik/etree"
)

// 申请退款
func (c *Client) Refund(body RefundBody) (wxRsp RefundResponse, err error) {
	// 业务逻辑
	bytes, err := c.doWeChatWithCert("secapi/pay/refund", body, nil)
	if err != nil {
		return
	}
	// 结果校验
	if err = c.doVerifySign(bytes, true); err != nil {
		return
	}
	// 解析返回值
	err = c.refundParseResponse(bytes, &wxRsp)
	return
}

// 申请退款的参数
type RefundBody struct {
	TransactionId string `json:"transaction_id"`            // 微信支付订单号
	OutTradeNo    string `json:"out_trade_no"`              // 商户系统内部订单号，要求32个字符内，只能是数字、大小写字母_-|*@ ，且在同一个商户号下唯一。
	OutRefundNo   string `json:"out_refund_no"`             // 商户系统内部的退款单号，商户系统内部唯一，只能是数字、大小写字母_-|*@ ，同一退款单号多次请求只退一笔。
	TotalFee      int    `json:"total_fee"`                 // 订单总金额，单位为分，只能为整数，详见支付金额
	RefundFee     int    `json:"refund_fee"`                // 退款总金额，单位为分，只能为整数，可部分退款。详见支付金额
	RefundFeeType string `json:"refund_fee_type,omitempty"` // 退款货币类型，需与支付一致，或者不填。符合ISO 4217标准的三位字母代码，默认人民币：CNY
	RefundDesc    string `json:"refund_desc,omitempty"`     // 现退款原因
	RefundAccount string `json:"refund_account,omitempty"`  // 退款资金来源(见constatnt定义)
	NotifyUrl     string `json:"notify_url,omitempty"`      // 异步接收微信支付退款结果通知的回调地址
}

// 申请退款的返回值
type RefundResponse struct {
	ResponseModel
	ServiceResponseModel
	TransactionId       string `xml:"transaction_id"`
	OutTradeNo          string `xml:"out_trade_no"`
	OutRefundNo         string `xml:"out_refund_no"`
	RefundId            string `xml:"refund_id"`
	RefundFee           int    `xml:"refund_fee"`
	SettlementRefundFee int    `xml:"settlement_refund_fee"`
	TotalFee            int    `xml:"total_fee"`
	SettlementTotalFee  int    `xml:"settlement_total_fee"`
	FeeType             string `xml:"fee_type"`
	CashFee             int    `xml:"cash_fee"`
	CashRefundFee       int    `xml:"cash_refund_fee"`
	CouponRefundFee     int    `xml:"coupon_refund_fee"`
	CouponRefundCount   int    `xml:"coupon_refund_count"`
	// 使用coupon_refund_count的序号生成的优惠券项
	RefundCoupons []CouponResponseModel `xml:"-"`
}

// 申请退款-解析XML返回值
func (c *Client) refundParseResponse(xmlStr []byte, rsp *RefundResponse) (err error) {
	// 常规解析
	if err = xml.Unmarshal(xmlStr, rsp); err != nil {
		return
	}
	// 解析CouponRefundCount的对应项
	if rsp.CouponRefundCount > 0 {
		doc := etree.NewDocument()
		if err = doc.ReadFromBytes(xmlStr); err != nil {
			return
		}
		root := doc.SelectElement("xml")
		if root == nil {
			err = errors.New("xml格式错误")
			return
		}
		for i := 0; i < rsp.CouponRefundCount; i++ {
			m := NewCouponResponseModel(root, "coupon_refund_id_%d", "coupon_type_%d", "coupon_refund_fee_%d", i)
			rsp.RefundCoupons = append(rsp.RefundCoupons, m)
		}
	}
	return
}