package services

import (
	"bytes"
	"context"
	"encoding/gob"
	"errors"
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"platform/pkg/env"
	"platform/pkg/u"
	"platform/web/core"
	e "platform/web/events"
	g "platform/web/globals"
	m "platform/web/models"
	q "platform/web/queries"
	"time"

	"github.com/hibiken/asynq"
	"github.com/shopspring/decimal"
	wecahtpaycore "github.com/wechatpay-apiv3/wechatpay-go/core"

	"github.com/smartwalle/alipay/v3"
	"github.com/wechatpay-apiv3/wechatpay-go/services/partnerpayments/h5"
	"github.com/wechatpay-apiv3/wechatpay-go/services/payments/native"
)

func init() {
	gob.Register(&CreateResourceData{})
	gob.Register(&UpdateBalanceData{})
}

var Trade = &tradeService{}

type tradeService struct {
}

// 创建交易
func (s *tradeService) Create(user *m.User, tradeData *CreateTradeData, productData ProductData) (*CreateTradeResult, error) {
	if user == nil {
		return nil, core.NewBizErr("用户未登录")
	}

	detail, err := productData.TradeDetail(user)
	if err != nil {
		return nil, core.NewServErr("获取产品支付信息失败", err)
	}

	now := time.Now()
	platform := tradeData.Platform
	method := tradeData.Method
	expireIn := time.Duration(env.TradeExpire) * time.Second
	expireAt := now.Add(expireIn)

	// 生成订单号
	tradeNo, err := ID.GenSerial()
	if err != nil {
		return nil, core.NewServErr("生成订单号失败", err)
	}

	// 实际支付金额，只在创建真实订单时使用
	amountReal := detail.Actual
	if env.RunMode == env.RunModeDev {
		amountReal = decimal.NewFromFloat(0.01)
	}

	// 提交支付订单
	var paymentUrl string
	switch {

	// 支付宝 + 电脑网站
	case method == m.TradeMethodAlipay && platform == m.TradePlatformPC:
		resp, err := g.Alipay.TradePagePay(alipay.TradePagePay{
			QRPayMode:   "4",
			QRCodeWidth: "196", // 二维码宽度需要-4，支付宝页面布局有问题
			Trade: alipay.Trade{
				ProductCode: "FAST_INSTANT_TRADE_PAY",
				OutTradeNo:  tradeNo,
				Subject:     detail.Subject,
				TotalAmount: amountReal.StringFixed(2),
				TimeExpire:  expireAt.Format("2006-01-02 15:04:05"),
			},
		})
		if err != nil {
			return nil, err
		}
		paymentUrl = resp.String()

	// 微信 + 电脑网站
	case method == m.TradeMethodWechat && platform == m.TradePlatformPC:
		resp, _, err := g.WechatPay.Native.Prepay(context.Background(), native.PrepayRequest{
			Appid:       &env.WechatPayAppId,
			Mchid:       &env.WechatPayMchId,
			OutTradeNo:  &tradeNo,
			Description: &detail.Subject,
			TimeExpire:  &expireAt,
			NotifyUrl:   &env.WechatPayCallbackUrl,
			Amount: &native.Amount{
				Total: u.P(amountReal.Mul(decimal.NewFromInt(100)).Round(0).IntPart()),
			},
		})
		if err != nil {
			return nil, err
		}
		paymentUrl = *resp.CodeUrl

	// 微信 + 手机网站
	case method == m.TradeMethodWechat && platform == m.TradePlatformMobile:
		resp, _, err := g.WechatPay.H5.Prepay(context.Background(), h5.PrepayRequest{
			SpAppid:     &env.WechatPayAppId,
			SpMchid:     &env.WechatPayMchId,
			OutTradeNo:  &tradeNo,
			Description: &detail.Subject,
			TimeExpire:  &expireAt,
			NotifyUrl:   &env.WechatPayCallbackUrl,
			Amount: &h5.Amount{
				Total: u.P(amountReal.Mul(decimal.NewFromInt(100)).Round(0).IntPart()),
			},
		})
		if err != nil {
			return nil, err
		}
		paymentUrl = *resp.H5Url

	// 商福通 + 电脑网站
	case
		method == m.TradeMethodSftAlipay && platform == m.TradePlatformPC,
		method == m.TradeMethodSftWechat && platform == m.TradePlatformPC:

		var payType g.SftPayType
		switch method {
		case m.TradeMethodSftAlipay:
			payType = g.SftAlipay
		case m.TradeMethodSftWechat:
			payType = g.SftWeChat
		}

		resp, err := g.SFTPay.PaymentScanPay(&g.PaymentScanPayReq{
			MchOrderNo:   tradeNo,
			Subject:      detail.Subject,
			Body:         detail.Subject,
			Amount:       amountReal.Mul(decimal.NewFromInt(100)).Round(0).IntPart(),
			PayType:      payType,
			Currency:     "cny",
			ClientIp:     "123.52.74.23",
			OrderTimeout: u.P(expireAt.Format("2006-01-02 15:04:05")),
		})
		if err != nil {
			return nil, err
		}
		paymentUrl = u.Z(u.Z(resp.PayInfo).QrCodeUrl)

	// 商福通 + 手机网站
	case
		method == m.TradeMethodSftAlipay && platform == m.TradePlatformMobile,
		method == m.TradeMethodSftWechat && platform == m.TradePlatformMobile:

		var payType g.SftPayType
		switch method {
		case m.TradeMethodSftAlipay:
			payType = g.SftAlipay
		case m.TradeMethodSftWechat:
			payType = g.SftWeChat
		}

		resp, err := g.SFTPay.PaymentH5Pay(&g.PaymentH5PayReq{
			MchOrderNo:   tradeNo,
			Subject:      detail.Subject,
			Body:         detail.Subject,
			Amount:       amountReal.Mul(decimal.NewFromInt(100)).Round(0).IntPart(),
			PayType:      payType,
			Currency:     "cny",
			ClientIp:     "123.52.74.23",
			OrderTimeout: u.P(expireAt.Format("2006-01-02 15:04:05")),
		})
		if err != nil {
			return nil, err
		}
		paymentUrl = u.Z(u.Z(resp.PayInfo).PayUrl)

	// 不支持的支付方式
	default:
		slog.Warn(ErrTransactionNotSupported.Error(), "method", method, "platform", platform)
		return nil, ErrTransactionNotSupported
	}

	// 保存订单
	err = q.Trade.Create(&m.Trade{
		UserID:     user.ID,
		InnerNo:    tradeNo,
		Type:       detail.Type,
		Subject:    detail.Subject,
		Amount:     detail.Actual,
		Method:     method,
		Platform:   platform,
		PaymentURL: &paymentUrl,
	})
	if err != nil {
		return nil, core.NewServErr("保存交易订单失败", err)
	}

	// 缓存产品数据
	w := bytes.Buffer{}
	gob.NewEncoder(&w).Encode(detail)
	err = g.Redis.Set(
		context.Background(),
		tradeProductKey(tradeNo),
		w.Bytes(),
		expireIn,
	).Err()
	if err != nil {
		return nil, core.NewServErr("保存购买信息失败", err)
	}

	// 提交异步关闭事件
	_, err = g.Asynq.Enqueue(e.NewCloseTradeTask(user.ID, tradeNo, method), asynq.ProcessAt(expireAt))
	if err != nil {
		return nil, core.NewServErr("提交异步关闭事件失败", err)
	}

	return &CreateTradeResult{
		PayUrl:  paymentUrl,
		TradeNo: tradeNo,
	}, nil
}

// 完成交易
func (s *tradeService) CompleteTrade(user *m.User, ref *TradeRef) error {

	// 检查订单状态
	result, err := s.CheckTrade(ref)
	if err != nil {
		return core.NewServErr("检查订单状态失败", err)
	}
	if result.Status != m.TradeStatusSuccess {
		switch result.Status {
		case m.TradeStatusPending:
			return core.NewBizErr("订单未支付")
		case m.TradeStatusCanceled:
			return core.NewBizErr("订单已过期")
		}
	}

	// 更新交易状态
	err = s.OnCompleteTrade(user, ref.TradeNo, result.TransId, &result.Success)
	if err != nil {
		return core.NewServErr("处理交易失败", err)
	}

	return nil
}
func (s *tradeService) OnCompleteTrade(user *m.User, interNo string, outerNo string, result *TradeSuccessResult) error {

	// 获取交易信息
	trade, err := q.Trade.
		Where(q.Trade.InnerNo.Eq(interNo)).
		Take()
	if err != nil {
		return core.NewBizErr("获取交易信息失败", err)
	}

	// 检查交易状态
	switch trade.Status {
	case m.TradeStatusCanceled:
		return core.NewBizErr("交易已取消")
	case m.TradeStatusSuccess:
		return nil // 跳过更新交易信息
	case m.TradeStatusPending:
	}

	// 恢复购买信息；如果反序列化失败，检查开头 init 函数中是否注册了对应的 struct 类型
	detailBytes, err := g.Redis.Get(context.Background(), tradeProductKey(interNo)).Bytes()
	if err != nil {
		return core.NewServErr("恢复购买信息失败", err)
	}

	var detail TradeDetail
	r := bytes.NewReader(detailBytes)
	if err := gob.NewDecoder(r).Decode(&detail); err != nil {
		return core.NewServErr("解析购买信息失败", err)
	}

	err = q.Q.Transaction(func(q *q.Query) error {
		// 更新交易信息
		_, err := q.Trade.
			Where(
				q.Trade.InnerNo.Eq(interNo),
				q.Trade.Status.Eq(int(m.TradeStatusPending)),
			).
			UpdateSimple(
				q.Trade.Status.Value(int(m.TradeStatusSuccess)),
				q.Trade.OuterNo.Value(outerNo),
				q.Trade.Payment.Value(result.Actual),
				q.Trade.Acquirer.Value(int(result.Acquirer)),
				q.Trade.CompletedAt.Value(result.Time),
			)
		if err != nil {
			return core.NewServErr("更新交易信息失败", err)
		}

		switch trade.Type {
		case m.TradeTypeRecharge:

			// 生成账单
			bill, err := Bill.CreateForBalance(q, user.ID, trade.ID, &detail)
			if err != nil {
				return core.NewServErr("生成账单失败", err)
			}

			// 更新用户余额
			if err := User.UpdateBalance(q, user, detail.Actual, "充值余额", nil, &bill.ID); err != nil {
				return err
			}

		case m.TradeTypePurchase:
			data, ok := detail.Product.(*CreateResourceData)
			if !ok {
				return core.NewServErr("购买信息解析失败", nil)
			}

			// 保存套餐
			resource, err := Resource.Create(q, user.ID, result.Time, data)
			if err != nil {
				return core.NewServErr("创建套餐失败", err)
			}

			// 生成账单
			_, err = Bill.CreateForResource(q, user.ID, resource.ID, &trade.ID, &detail)
			if err != nil {
				return core.NewServErr("生成账单失败", err)
			}

			// 核销优惠券
			if detail.CouponUserId != nil {
				err = Coupon.UseCoupon(q, *detail.CouponUserId)
				if err != nil {
					return core.NewServErr("核销优惠券失败", err)
				}
			}
		}

		return nil
	})
	if err != nil {
		return err
	}

	return nil
}

// 取消交易
func (s *tradeService) CancelTrade(ref *TradeRef) error {
	now := time.Now()

	switch ref.Method {
	case m.TradeMethodAlipay:
		resp, err := g.Alipay.TradeCancel(context.Background(), alipay.TradeCancel{
			OutTradeNo: ref.TradeNo,
		})
		if err != nil {
			return core.NewServErr("上游取消交易失败", err)
		}
		if resp.Code != alipay.CodeSuccess {
			slog.Error("支付宝交易取消失败", "code", resp.Code, "sub_code", resp.SubCode, "msg", resp.Msg)
			return errors.New("上游取消交易失败")
		}

	case m.TradeMethodWechat:
		resp, err := g.WechatPay.Native.CloseOrder(context.Background(), native.CloseOrderRequest{
			Mchid:      &env.WechatPayMchId,
			OutTradeNo: &ref.TradeNo,
		})
		if err != nil {
			return core.NewServErr("上游取消交易失败", err)
		}
		if resp.Response.StatusCode != http.StatusNoContent {
			body, err := io.ReadAll(resp.Response.Body)
			if err != nil {
				slog.Error("读取微信交易取消响应失败", "error", err)
				return core.NewServErr("上游取消交易失败", err)
			}
			slog.Error("微信交易取消失败", "code", resp.Response.StatusCode, "body", string(body))
			return errors.New("上游取消交易失败")
		}

	case m.TradeMethodSft, m.TradeMethodSftAlipay, m.TradeMethodSftWechat:
		_, err := g.SFTPay.OrderClose(&g.OrderCloseReq{
			MchOrderNo: &ref.TradeNo,
		})
		if err != nil {
			slog.Debug(fmt.Sprintf("订单无需关闭: %s", err.Error()))
			return nil
		}

	default:
		return ErrTransactionNotSupported
	}

	err := s.OnCancelTrade(ref.TradeNo, now)
	if err != nil {
		return err
	}

	return nil
}
func (s *tradeService) OnCancelTrade(tradeNo string, now time.Time) error {
	_, err := q.Trade.
		Where(
			q.Trade.InnerNo.Eq(tradeNo),
			q.Trade.Status.Eq(int(m.TradeStatusPending)),
		).
		UpdateSimple(
			q.Trade.Status.Value(int(m.TradeStatusCanceled)),
			q.Trade.CanceledAt.Value(now),
		)
	if err != nil {
		return core.NewServErr("更新交易状态失败", err)
	}

	return nil
}

// 交易退款
func (s *tradeService) RefundTrade(ref *TradeRef) error {
	panic("todo")
}
func (s *tradeService) OnRefundTrade(q *q.Query, tradeNo string, now time.Time) error {
	panic("todo")
}

// 检查交易状态
func (s *tradeService) CheckTrade(ref *TradeRef) (*CheckTradeResult, error) {
	var tradeNo = ref.TradeNo
	var method = ref.Method

	// 检查交易号是否存在
	var result CheckTradeResult
	switch method {

	// 支付宝
	case m.TradeMethodAlipay:

		// 查询交易状态
		resp, err := g.Alipay.TradeQuery(context.Background(), alipay.TradeQuery{
			OutTradeNo: tradeNo,
		})
		if err != nil {
			return nil, err
		}
		if resp.Code != alipay.CodeSuccess {
			slog.Warn("支付宝交易查询失败", "code", resp.Code, "sub_code", resp.SubCode, "msg", resp.Msg)
			return nil, errors.New("交易查询失败")
		}

		// 填充返回值
		result.TransId = resp.TradeNo
		switch resp.TradeStatus {

		case alipay.TradeStatusWaitBuyerPay:
			result.Status = m.TradeStatusPending

		case alipay.TradeStatusClosed:
			result.Status = m.TradeStatusCanceled

		case alipay.TradeStatusSuccess, alipay.TradeStatusFinished:
			result.Status = m.TradeStatusSuccess
			result.Success.Acquirer = m.TradeAcquirerAlipay
			result.Success.Actual, err = decimal.NewFromString(resp.ReceiptAmount)
			if err != nil {
				return nil, err
			}
			result.Success.Time, err = time.Parse("2006-01-02 15:04:05", resp.SendPayDate)
			if err != nil {
				return nil, err
			}
		}

	// 微信
	case m.TradeMethodWechat:

		// 查询交易状态
		resp, _, err := g.WechatPay.Native.QueryOrderByOutTradeNo(context.Background(), native.QueryOrderByOutTradeNoRequest{
			OutTradeNo: &tradeNo,
			Mchid:      &env.WechatPayMchId,
		})
		if err != nil {
			var apiErr *wecahtpaycore.APIError
			if errors.As(err, &apiErr) {
				if apiErr.Code == "ORDER_NOT_EXIST" {
					return nil, core.NewBizErr("订单不存在")
				}
				return nil, core.NewServErr(
					fmt.Sprintf("微信上游接口异常: code=%v，message=%v", apiErr.Code, apiErr.Message),
					apiErr,
				)
			}
			return nil, core.NewServErr(fmt.Sprintf("微信上游支付接口异常: %s", err.Error()))
		}

		// 填充返回值
		result.TransId = *resp.TransactionId
		switch *resp.TradeState {

		case "NOTPAY":
			result.Status = m.TradeStatusPending

		case "CLOSED":
			result.Status = m.TradeStatusCanceled

		case "SUCCESS", "REFUND":
			result.Status = m.TradeStatusSuccess
			result.Success.Acquirer = m.TradeAcquirerWechat
			result.Success.Actual = decimal.NewFromInt(*resp.Amount.PayerTotal).Div(decimal.NewFromInt(100))
			result.Success.Time, err = time.Parse(time.RFC3339, *resp.SuccessTime)
			if err != nil {
				return nil, err
			}
		}

	// 商福通
	case m.TradeMethodSft, m.TradeMethodSftAlipay, m.TradeMethodSftWechat:

		// 查询交易状态
		resp, err := g.SFTPay.QueryTrade(&g.QueryTradeReq{
			MchOrderNo: &tradeNo,
		})
		if err != nil {
			return nil, err
		}

		// 填充返回值
		if resp.PayOrderId == nil {
			return nil, errors.New("商福通交易号不存在")
		}
		result.TransId = *resp.PayOrderId

		switch resp.State {

		case g.SftInit, g.SftTradeAwait, g.SftTradeFail:
			result.Status = m.TradeStatusPending

		case g.SftTradeClosed, g.SftTradeCancel:
			result.Status = m.TradeStatusCanceled

		case g.SftTradeSuccess, g.SftTradeRefund, g.SftRefundIng:
			result.Status = m.TradeStatusSuccess
			switch resp.PayType {
			case "WECHAT":
				result.Success.Acquirer = m.TradeAcquirerWechat
			case "ALIPAY":
				result.Success.Acquirer = m.TradeAcquirerAlipay
			case "UNIONPAY":
				result.Success.Acquirer = m.TradeAcquirerUnionPay
			}
			result.Success.Actual = decimal.NewFromInt(resp.Amount).Div(decimal.NewFromInt(100))
			result.Success.Time, err = time.Parse("2006-01-02 15:04:05", *resp.PayTime)
			if err != nil {
				return nil, err
			}
		}

	// 不支持的支付方式
	default:
		return nil, ErrTransactionNotSupported
	}

	return &result, nil
}

func tradeProductKey(no string) string {
	return fmt.Sprintf("trade:%s:product", no)
}

func tradeLockKey(no string) string {
	return fmt.Sprintf("trade:%s:lock", no)
}

type CreateTradeData struct {
	Platform m.TradePlatform `json:"platform" validate:"required"`
	Method   m.TradeMethod   `json:"method" validate:"required"`
}

type CreateTradeResult struct {
	PayUrl  string `json:"pay_url"`
	TradeNo string `json:"trade_no"`
}

type TradeRef struct {
	TradeNo string        `json:"trade_no" query:"trade_no" validate:"required"`
	Method  m.TradeMethod `json:"method" validate:"required"`
}

type CheckTradeResult struct {
	TransId string
	Status  m.TradeStatus
	Success TradeSuccessResult
}

type TradeSuccessResult struct {
	Acquirer m.TradeAcquirer
	Actual   decimal.Decimal
	Time     time.Time
}

type OnTradeCompletedData struct {
	TradeNo string
	TransId string
	*TradeSuccessResult
}

type ProductData interface {
	TradeDetail(user *m.User) (*TradeDetail, error)
}

type TradeDetail struct {
	Product      ProductData     `json:"product"`
	Type         m.TradeType     `json:"type"`
	Subject      string          `json:"subject"`
	Amount       decimal.Decimal `json:"amount"`
	Discounted   decimal.Decimal `json:"discounted"`
	Actual       decimal.Decimal `json:"actual"`
	DiscountId   *int32          `json:"discount_id,omitempty"`
	CouponUserId *int32          `json:"coupon_id,omitempty"`
}

type TradeErr string

func (e TradeErr) Error() string {
	return string(e)
}

var (
	ErrTransactionNotSupported = core.NewBizErr("不支持的支付方式")
)