package services

import (
	"context"
	"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/payments/native"
	"gorm.io/gorm"
)

var Trade = &tradeService{}

type tradeService struct {
}

// 创建交易
func (s *tradeService) CreateTrade(uid int32, now time.Time, data *CreateTradeData) (*CreateTradeResult, error) {
	platform := data.Platform
	method := data.Method
	tType := data.Product.GetType()
	expire := time.Now().Add(30 * time.Minute)
	subject, err := data.Product.GetSubject()
	if err != nil {
		return nil, err
	}
	amount, err := data.Product.GetAmount()
	if err != nil {
		return nil, err
	}

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

	// 附加优惠券
	if data.CouponCode != nil {
		coupon, err := q.Coupon.
			Where(
				q.Coupon.Code.Eq(*data.CouponCode),
				q.Coupon.Status.Eq(int(m.CouponStatusUnused)),
			).
			Take()
		if err != nil {
			if errors.Is(err, gorm.ErrRecordNotFound) {
				return nil, errors.New("优惠券不存在或已失效")
			}
			return nil, err
		}

		expireAt := time.Time(u.Z(coupon.ExpireAt))
		if !expireAt.IsZero() && expireAt.Before(now) {
			_, err = q.Coupon.
				Where(q.Coupon.ID.Eq(coupon.ID)).
				Update(q.Coupon.Status, m.CouponStatusExpired)
			if err != nil {
				return nil, err
			}
			return nil, errors.New("优惠券已过期")
		}

		if amount.Cmp(coupon.MinAmount) < 0 {
			return nil, errors.New("订单金额未达到使用优惠券的条件")
		}

		if coupon.UserID != nil {
			switch *coupon.UserID {
			// 指定用户的优惠券
			case uid:
				amount = amount.Sub(coupon.Amount)
				if expireAt.IsZero() {
					_, err = q.Coupon.
						Where(q.Coupon.ID.Eq(coupon.ID)).
						Update(q.Coupon.Status, int(m.CouponStatusUsed))
					if err != nil {
						return nil, err
					}
				}
			// 该优惠券不属于当前用户
			default:
				return nil, errors.New("优惠券不属于当前用户")
			}
		} else {
			// 公开优惠券
			amount = amount.Sub(coupon.Amount)
		}
	}

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

	// 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:     subject,
				TotalAmount: amountReal.StringFixed(2),
				TimeExpire:  expire.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: &subject,
			TimeExpire:  &expire,
			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

	// 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
		default:
			panic("unhandled default case")
		}
		resp, err := g.SFTPay.PaymentScanPay(&g.PaymentScanPayReq{
			MchOrderNo:   tradeNo,
			Subject:      subject,
			Body:         subject,
			Amount:       amountReal.Mul(decimal.NewFromInt(100)).Round(0).IntPart(),
			PayType:      payType,
			Currency:     "cny",
			ClientIp:     "123.52.74.23",
			OrderTimeout: u.P(expire.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
		default:
			panic("unhandled default case")
		}
		resp, err := g.SFTPay.PaymentH5Pay(&g.PaymentH5PayReq{
			MchOrderNo:   tradeNo,
			Subject:      subject,
			Body:         subject,
			Amount:       amountReal.Mul(decimal.NewFromInt(100)).Round(0).IntPart(),
			PayType:      payType,
			Currency:     "cny",
			ClientIp:     "123.52.74.23",
			OrderTimeout: u.P(expire.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:     uid,
		InnerNo:    tradeNo,
		Type:       tType,
		Subject:    subject,
		Amount:     amount,
		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
	serialized, err := data.Product.Serialize()
	if err != nil {
		return nil, core.NewServErr("序列化产品信息失败", err)
	}

	err = g.Redis.Set(
		context.Background(),
		tradeProductKey(tradeNo),
		serialized,
		time.Duration(env.TradeExpire+10)*time.Second,
	).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
	closeAt := now.Add(time.Duration(env.TradeExpire) * time.Second)
	_, err = g.Asynq.Enqueue(e.NewCancelTrade(e.CompleteTradeData{
		TradeNo: tradeNo,
		Method:  method,
	}), asynq.ProcessAt(closeAt))
	if err != nil {
		return nil, core.NewServErr("提交异步关闭事件失败", err)
	}

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

// 完成交易
func (s *tradeService) CompleteTrade(data *ModifyTradeData) error {
	return g.Redsync.WithLock(tradeLockKey(data.TradeNo), func() error {

		// 检查订单状态
		result, err := s.CheckTrade(data)
		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
		trade, err := completeTrade(&OnTradeCompletedData{
			data.TradeNo,
			result.TransId,
			result.Success,
		})
		if err != nil {
			return core.NewServErr("处理交易失败", err)
		}

		// 处理交易完成事件
		err = afterTradeComplete(trade)
		if err != nil {
			return core.NewServErr("处理交易完成事件失败", err)
		}

		return nil
	})
}
func (s *tradeService) OnTradeCompleted(data *OnTradeCompletedData) error {
	return g.Redsync.WithLock(tradeLockKey(data.TradeNo), func() error {

		// 更新交易状态
		trade, err := completeTrade(data)
		if err != nil {
			return core.NewServErr("处理交易失败", err)
		}

		// 处理交易完成事件
		err = afterTradeComplete(trade)
		if err != nil {
			return core.NewServErr("处理交易完成事件失败", err)
		}

		return nil
	})
}
func completeTrade(data *OnTradeCompletedData) (*m.Trade, error) {
	var trade = new(m.Trade)
	var err = q.Q.Transaction(func(tx *q.Query) error {
		var tradeNo = data.TradeNo
		var transId = data.TransId
		var payment = data.Payment
		var acquirer = data.Acquirer
		var paidAt = data.Time

		// 获取交易信息
		var err error
		trade, err = q.Trade.
			Where(q.Trade.InnerNo.Eq(tradeNo)).
			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:
		}

		// 更新交易信息
		trade.Status = m.TradeStatusSuccess
		trade.OuterNo = &transId
		trade.Payment = payment
		trade.Acquirer = u.P(acquirer)
		trade.CompletedAt = u.P(paidAt)
		rs, err := q.Trade.
			Where(q.Trade.InnerNo.Eq(tradeNo), q.Trade.Status.Eq(int(m.TradeStatusPending))).
			Updates(trade)
		if rs.RowsAffected == 0 {
			return core.NewBizErr("交易状态已发生变化")
		}
		if err != nil {
			return core.NewServErr("更新交易信息失败", err)
		}

		return nil
	})
	if err != nil {
		return nil, err
	} else {
		return trade, err
	}
}
func afterTradeComplete(trade *m.Trade) error {

	// 恢复购买信息
	productData, err := g.Redis.Get(context.Background(), tradeProductKey(trade.InnerNo)).Result()
	if err != nil {
		return core.NewServErr("恢复购买信息失败", err)
	}

	// 执行资源创建
	var ComplementEvents = []CompleteEvent{
		ResourceOnTradeComplete{},
		UserOnTradeComplete{},
	}

	for _, event := range ComplementEvents {
		info, ok := event.Check(trade.Type)
		if !ok {
			continue
		}

		err = info.Deserialize(productData)
		if err != nil {
			return core.NewServErr("反序列化购买信息失败", err)
		}

		err = event.OnTradeComplete(info, trade)
		if err != nil {
			return core.NewServErr("处理交易完成事件失败", err)
		}
	}

	return nil
}

// 取消交易
func (s *tradeService) CancelTrade(data *ModifyTradeData, now time.Time) error {
	tradeNo := data.TradeNo
	method := data.Method

	return g.Redsync.WithLock(tradeLockKey(tradeNo), func() error {
		switch method {

		case m.TradeMethodAlipay:
			resp, err := g.Alipay.TradeCancel(context.Background(), alipay.TradeCancel{
				OutTradeNo: 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: &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: &tradeNo,
			})
			if err != nil {
				slog.Debug(fmt.Sprintf("订单无需关闭: %s", err.Error()))
				return nil
			}

		default:
			return ErrTransactionNotSupported
		}

		err := cancelTrade(tradeNo, now)
		if err != nil {
			return err
		}

		return nil
	})
}
func (s *tradeService) OnTradeCanceled(tradeNo string, now time.Time) error {
	err := g.Redsync.WithLock(tradeLockKey(tradeNo), func() error {
		return cancelTrade(tradeNo, now)
	})
	if err != nil {
		return core.NewServErr("处理交易取消失败", err)
	}
	return nil
}
func cancelTrade(tradeNo string, now time.Time) error {
	return q.Q.Transaction(func(q *q.Query) error {
		// 获取交易信息
		var status m.TradeStatus
		err := q.Trade.
			Where(q.Trade.InnerNo.Eq(tradeNo)).
			Select(q.Trade.Status).
			Scan(&status)
		if err != nil {
			return core.NewBizErr("获取交易信息失败", err)
		}

		// 检查交易状态
		switch status {
		case m.TradeStatusCanceled:
			return core.NewBizErr("交易已取消")
		case m.TradeStatusSuccess:
			return core.NewBizErr("交易已完成")
		case m.TradeStatusPending:
		}

		// 更新交易状态
		_, err = q.Trade.
			Where(q.Trade.InnerNo.Eq(tradeNo)).
			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(data *ModifyTradeData) error {
	panic("todo")
}
func (s *tradeService) OnTradeRefunded(q *q.Query, tradeNo string, now time.Time) error {
	panic("todo")
}

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

	// 检查交易号是否存在
	var result = new(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 = &TradeSuccessResult{}
			result.Success.Acquirer = m.TradeAcquirerAlipay
			result.Success.Payment, err = decimal.NewFromString(resp.TotalAmount)
			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 = &TradeSuccessResult{}
			result.Success.Acquirer = m.TradeAcquirerWechat
			result.Success.Payment = 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
		}

		if resp.PayOrderId == nil {
			return nil, errors.New("商福通交易号不存在")
		}

		// 填充返回值
		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
			result.Success = &TradeSuccessResult{}
			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.Payment = 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"`
	CouponCode *string         `json:"coupon_code"`
	Product    ProductInfo
}

type CreateTradeResult struct {
	TradeNo    string
	PaymentUrl string
}

type ModifyTradeData 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
	Payment  decimal.Decimal
	Time     time.Time
}

type OnTradeCompletedData struct {
	TradeNo string
	TransId string
	*TradeSuccessResult
}

type ProductInfo interface {
	GetType() m.TradeType
	GetSubject() (string, error)
	GetAmount() (decimal.Decimal, error)
	Serialize() (string, error)
	Deserialize(str string) error
}

type CompleteEvent interface {
	Check(t m.TradeType) (ProductInfo, bool)
	OnTradeComplete(info ProductInfo, trade *m.Trade) error
}

type TradeErr string

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

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