package service

import (
	"context"
	"encoding/json"
	"log/slog"
	"time"

	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/global"
	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/internal/dto"
	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/internal/mysqldao"
	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/internal/mysqlmodel"
	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/internal/redisdao"
	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/internal/redismodel"
	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/pkg/errcode"
	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/pkg/wechat"
	"github.com/redis/go-redis/v9"
)

// VirtualOrderCreate 创建虚拟支付订单：本地落单（pay_channel=2）并返回前端调起
// wx.requestVirtualPayment 所需的 signData / paySig / signature。
func (s *OrderService) VirtualOrderCreate(ctx context.Context, userID int64, request *dto.VirtualOrderCreateRequest) (*dto.VirtualOrderCreateResponse, *errcode.Error) {
	ctx, span := global.Tracer.Start(ctx, "svc.VirtualOrderCreate")
	defer span.End()

	if !wechat.IsVirtualPayEnabled() {
		return nil, errcode.VirtualPayNotEnabled
	}
	// 订单记录当前激活的虚拟支付环境（现网 0 / 沙箱 1），发货推送按此校验。
	xpayEnv, verr := wechat.GetVirtualPayEnv()
	if verr != nil {
		return nil, errcode.VirtualPayNotEnabled
	}

	goods, err := s.goodsDao.GoodsGetByCode(ctx, request.GoodsCode)
	if err != nil {
		if isNotFound(err) {
			return nil, errcode.GoodsNotFound
		}
		return nil, errcode.DatabaseError
	}
	if goods.Status != GoodsStatusOnShelf {
		return nil, errcode.GoodsOffShelf
	}
	if goods.ProductID == "" || goods.ProductStatus != GoodsProductPublished {
		return nil, errcode.VirtualPayGoodsNotPublished
	}
	// iOS 端微信限制最低支付 1 元（100 分），低于此金额调起支付必失败，提前拒绝以降低垃圾订单。
	// 注意：platform 由前端上报（不可作为安全边界，可伪造为 android 绕过此限制）；
	// 此校验仅作体验优化，不构成资损防线——真正的资损防线是发货推送 verifyXPayOrderPaid
	// 对微信侧订单真实性、金额、道具的反查。低金额商品在 iOS 上的垃圾订单靠过期清理兜底。
	if request.Platform == XPayPlatformIOS && goods.DiscountPrice < 100 {
		return nil, errcode.VirtualPayAmountTooLow
	}

	// 虚拟支付 signature 依赖用户 session_key（登录时缓存），缺失说明需重新登录。
	sessionKey, serr := redisdao.AuthSessionKeyGet(ctx, userID)
	if serr != nil {
		if serr == redis.Nil {
			return nil, errcode.UnauthorizedTokenError.WithDetails("缺少 session_key，请重新登录")
		}
		return nil, errcode.CacheError
	}

	orderNo := genOrderNo()
	expireTime := nowUnix() + orderPayTTLSeconds
	payAmount := goods.DiscountPrice
	platform := request.Platform

	order := &mysqlmodel.Order{
		OrderNo:       orderNo,
		UserID:        userID,
		GoodsID:       goods.ID,
		GoodsName:     goods.GoodsName,
		UnitPrice:     goods.DiscountPrice,
		TotalAmount:   payAmount,
		PayAmount:     payAmount,
		PayChannel:    PayChannelVirtual,
		OrderStatus:   OrderStatusPending,
		MemberDays:    goods.MemberDays,
		CosQuota:      goods.CosQuota,
		AIRecommendQuota: goods.AIRecommendQuota,
		ClosetShareQuota: goods.ClosetShareQuota,
		OutfitShareQuota: goods.OutfitShareQuota,
		ExpireTime:    expireTime,
		XPayProductID: goods.ProductID,
		XPayPlatform:  platform,
		XPayEnv:       int8(xpayEnv),
	}
	if cerr := s.orderDao.OrderCreate(ctx, order); cerr != nil {
		return nil, errcode.VirtualOrderCreateFailed
	}

	sign, perr := wechat.BuildPaymentSign(
		global.VirtualPaySetting.OfferID,
		goods.ProductID,
		orderNo,
		"",
		sessionKey,
		payAmount,
	)
	if perr != nil {
		return nil, errcode.VirtualOrderCreateFailed
	}

	return &dto.VirtualOrderCreateResponse{
		OrderNo:    orderNo,
		PayAmount:  payAmount,
		ExpireTime: expireTime,
		SignData:   sign.SignData,
		PaySig:     sign.PaySig,
		Signature:  sign.Signature,
	}, nil
}

// ---- 消息推送回调 ----

// XPayNotify 处理虚拟支付消息推送（发货/退款/iOS 退款问询/其它），返回应答报文。
func (s *OrderService) XPayNotify(ctx context.Context, raw []byte) []byte {
	ctx, span := global.Tracer.Start(ctx, "svc.XPayNotify")
	defer span.End()

	base, err := wechat.ParseNotify(raw)
	if err != nil {
		slog.ErrorContext(ctx, "xpay notify parse failed", "error", err)
		return wechat.BuildNotifyResponse(false)
	}

	switch base.Event {
	case wechat.EventGoodsDeliverNotify:
		var deliver wechat.XPayGoodsDeliverNotify
		if err := json.Unmarshal(raw, &deliver); err != nil {
			slog.ErrorContext(ctx, "xpay deliver notify decode failed", "error", err)
			return wechat.BuildNotifyResponse(false)
		}
		if e := s.handleGoodsDeliver(ctx, &deliver, string(raw)); e != nil {
			slog.ErrorContext(ctx, "xpay deliver notify handle failed", "error", e)
			return wechat.BuildNotifyResponse(false)
		}
		return wechat.BuildNotifyResponse(true)

	case wechat.EventRefundNotify:
		var refund wechat.XPayRefundNotify
		if err := json.Unmarshal(raw, &refund); err != nil {
			slog.ErrorContext(ctx, "xpay refund notify decode failed", "error", err)
			return wechat.BuildNotifyResponse(false)
		}
		if e := s.handleRefundNotify(ctx, &refund); e != nil {
			slog.ErrorContext(ctx, "xpay refund notify handle failed", "error", e)
			return wechat.BuildNotifyResponse(false)
		}
		return wechat.BuildNotifyResponse(true)

	case wechat.EventIOSRefundQueryNotify:
		var query wechat.XPayIOSRefundQueryNotify
		if err := json.Unmarshal(raw, &query); err != nil {
			slog.ErrorContext(ctx, "xpay ios refund query decode failed", "error", err)
			return wechat.BuildNotifyResponse(false)
		}
		return s.handleIOSRefundQuery(ctx, &query)

	default:
		// 投诉/代币/风控等推送：结构化记录即可，暂不实现业务。
		slog.WarnContext(ctx, "xpay notify ignored", "event", base.Event, "out_trade_no", base.OutTradeNo)
		return wechat.BuildNotifyResponse(true)
	}
}

// verifyXPayOrderPaid 反查微信侧订单真实性：消息推送无签名，发货前必须通过
// query_order（带 HMAC 签名的服务端 API）确认订单已真实支付、实付金额一致，
// 防止伪造发货推送零成本获取权益。任一校验不通过返回错误（fail-closed，触发微信重试）。
func (s *OrderService) verifyXPayOrderPaid(ctx context.Context, order *mysqlmodel.Order, deliver *wechat.XPayGoodsDeliverNotify) *errcode.Error {
	if deliver.OpenID == "" {
		slog.ErrorContext(ctx, "xpay deliver: empty openid", "order_no", order.OrderNo)
		return errcode.OrderRealityCheckFailed
	}

	info, err := wechat.QueryOrder(ctx, deliver.OpenID, deliver.OutTradeNo, "")
	if err != nil {
		slog.ErrorContext(ctx, "xpay deliver: query order failed",
			"order_no", order.OrderNo, "error", err)
		return errcode.OrderRealityCheckFailed
	}

	// 微信侧无支付记录/未支付：伪造推送或数据异常，拒绝发放。
	if !wechat.IsOrderPaidStatus(info.Order.Status) {
		slog.ErrorContext(ctx, "xpay deliver: order not paid in wechat side",
			"order_no", order.OrderNo, "query_status", info.Order.Status)
		return errcode.OrderRealityCheckFailed
	}
	// 反查金额必须与下单快照一致（资损防线）。
	if info.Order.PaidFee != order.PayAmount {
		slog.ErrorContext(ctx, "xpay deliver: query amount mismatch",
			"order_no", order.OrderNo, "query_amount", info.Order.PaidFee, "order_amount", order.PayAmount)
		return errcode.OrderRealityCheckFailed
	}
	// 道具一致性由推送报文层校验（deliver.GoodsInfo.ProductID 对订单快照）；
	// query_order 不回传 product_id，无法在此二次核对，故不再重复校验。
	return nil
}

// verifyXPayRefund 反查微信侧退款真实性：退款推送无签名，回退权益前必须通过
// query_order（带 HMAC 签名的服务端 API）确认订单在微信侧已真实退款、金额一致，
// 防止伪造退款推送回收权益。任一校验不通过返回错误（fail-closed，触发微信重试）。
func (s *OrderService) verifyXPayRefund(ctx context.Context, order *mysqlmodel.Order, refund *wechat.XPayRefundNotify) *errcode.Error {
	if refund.OpenID == "" {
		slog.ErrorContext(ctx, "xpay refund: empty openid", "order_no", order.OrderNo)
		return errcode.OrderRealityCheckFailed
	}

	info, err := wechat.QueryOrder(ctx, refund.OpenID, refund.OutTradeNo, "")
	if err != nil {
		slog.ErrorContext(ctx, "xpay refund: query order failed",
			"order_no", order.OrderNo, "error", err)
		return errcode.OrderRealityCheckFailed
	}

	// 微信侧无退款记录/未退款：伪造推送或数据异常，拒绝回退权益。
	if !wechat.IsOrderRefundedStatus(info.Order.Status) {
		slog.ErrorContext(ctx, "xpay refund: order not refunded in wechat side",
			"order_no", order.OrderNo, "query_status", info.Order.Status)
		return errcode.OrderRealityCheckFailed
	}
	// 反查退款金额必须与推送一致（资损防线）。
	// 退款单用 refund_fee；支付单退款后用 paid_fee - left_fee 推算累计已退金额。
	refundedFee := info.Order.RefundFee
	if refundedFee <= 0 {
		refundedFee = info.Order.PaidFee - info.Order.LeftFee
	}
	if refundedFee != refund.RefundFee {
		slog.ErrorContext(ctx, "xpay refund: refund amount mismatch",
			"order_no", order.OrderNo, "query_refunded_fee", refundedFee, "notify_refund_fee", refund.RefundFee)
		return errcode.OrderRealityCheckFailed
	}
	return nil
}

// handleGoodsDeliver 处理道具发货推送：幂等锁 + 金额/道具校验 + 条件流转 + 发放权益。
func (s *OrderService) handleGoodsDeliver(ctx context.Context, deliver *wechat.XPayGoodsDeliverNotify, raw string) *errcode.Error {
	lockKey := fmtLockKey(redismodel.KeyLockPayCallback, deliver.OutTradeNo)
	lockVal := genUUID()
	if ok, _ := redisdao.TryLock(ctx, lockKey, lockVal, 30*time.Second); !ok {
		return nil // 并发回调，交由持锁者处理。
	}
	defer func() { _ = redisdao.Unlock(ctx, lockKey, lockVal) }()

	order, gerr := s.orderDao.OrderGetByOrderNo(ctx, deliver.OutTradeNo)
	if gerr != nil {
		if isNotFound(gerr) {
			slog.ErrorContext(ctx, "xpay deliver: order not found", "out_trade_no", deliver.OutTradeNo)
			return errcode.OrderRealityCheckFailed
		}
		return errcode.DatabaseError
	}

	// 仅虚拟支付订单走此链路，防止与普通支付回调串单。
	if order.PayChannel != PayChannelVirtual {
		slog.ErrorContext(ctx, "xpay deliver: order not virtual pay", "order_no", order.OrderNo, "pay_channel", order.PayChannel)
		return errcode.OrderRealityCheckFailed
	}
	// 防篡改：道具 ID 与实付金额必须与下单快照一致。
	if deliver.GoodsInfo.ProductID != order.XPayProductID {
		slog.ErrorContext(ctx, "xpay deliver: product mismatch",
			"order_no", order.OrderNo, "notify_product", deliver.GoodsInfo.ProductID, "order_product", order.XPayProductID)
		return errcode.OrderRealityCheckFailed
	}
	if deliver.GoodsInfo.ActualPrice != order.PayAmount {
		slog.ErrorContext(ctx, "xpay deliver: amount mismatch",
			"order_no", order.OrderNo, "notify_amount", deliver.GoodsInfo.ActualPrice, "order_amount", order.PayAmount)
		return errcode.OrderRealityCheckFailed
	}
	// 防环境串单：沙箱推送不得发放现网订单。
	if int8(deliver.Env) != order.XPayEnv {
		slog.ErrorContext(ctx, "xpay deliver: env mismatch",
			"order_no", order.OrderNo, "notify_env", deliver.Env, "order_env", order.XPayEnv)
		return errcode.OrderRealityCheckFailed
	}

	// 订单真实性反查：消息推送无签名，必须反查微信侧订单确认真实支付，
	// 防止伪造发货推送零成本获取权益；未通过返回错误 -> 应答 ErrCode:1，微信重试。
	if verr := s.verifyXPayOrderPaid(ctx, order, deliver); verr != nil {
		return verr
	}

	// 条件流转：待支付 -> 已支付，防重复回调。
	updated, uerr := s.orderDao.OrderUpdateStatusByOrderNo(ctx, deliver.OutTradeNo, OrderStatusPending, OrderStatusPaid)
	if uerr != nil {
		return errcode.DatabaseError
	}
	if updated {
		s.finalizeVirtualPaidOrder(ctx, order, deliver.WeChatPayInfo.PaidTime, deliver.WeChatPayInfo.TransactionID, raw)
		return nil
	}

	// 流转失败：处理「订单已过期但用户实际已付款」的竞态（与普通支付 PayNotify 一致）。
	current, gerr := s.orderDao.OrderGetByOrderNo(ctx, deliver.OutTradeNo)
	if gerr != nil {
		if isNotFound(gerr) {
			return nil
		}
		return errcode.DatabaseError
	}
	switch current.OrderStatus {
	case OrderStatusPaid:
		// 已被并发回调处理，兜底补发（幂等）。
		_ = s.orderDao.OrderUpdateByOrderNo(ctx, current.OrderNo, map[string]any{
			"pay_time":       resolvePaidTime(deliver.WeChatPayInfo.PaidTime),
			"transaction_id": deliver.WeChatPayInfo.TransactionID,
			"callback_raw":   raw,
		})
		s.grantOrderBenefits(ctx, current)
	case OrderStatusExpired:
		// 订单被系统过期但用户已付款：过期 -> 已支付并补发货。
		if ok, uerr := s.orderDao.OrderUpdateStatusByOrderNo(ctx, deliver.OutTradeNo, OrderStatusExpired, OrderStatusPaid); uerr != nil {
			return errcode.DatabaseError
		} else if ok {
			s.finalizeVirtualPaidOrder(ctx, current, deliver.WeChatPayInfo.PaidTime, deliver.WeChatPayInfo.TransactionID, raw)
		}
	case OrderStatusCancelled:
		// 防御分支：历史上已取消的虚拟支付订单用户仍完成了支付，补发货避免「钱已扣、权益不到账」。
		// 当前虚拟支付订单已禁止取消，此分支兜底存量数据与并发竞态。
		if ok, uerr := s.orderDao.OrderUpdateStatusByOrderNo(ctx, deliver.OutTradeNo, OrderStatusCancelled, OrderStatusPaid); uerr != nil {
			return errcode.DatabaseError
		} else if ok {
			s.finalizeVirtualPaidOrder(ctx, current, deliver.WeChatPayInfo.PaidTime, deliver.WeChatPayInfo.TransactionID, raw)
		}
	}
	return nil
}

// handleRefundNotify 处理退款推送：复用退款成功回退权益链路（settleRefundSuccess）。
func (s *OrderService) handleRefundNotify(ctx context.Context, refund *wechat.XPayRefundNotify) *errcode.Error {
	lockKey := fmtLockKey(redismodel.KeyLockRefundCallback, refund.RefundOrderID)
	lockVal := genUUID()
	if ok, _ := redisdao.TryLock(ctx, lockKey, lockVal, 30*time.Second); !ok {
		return nil
	}
	defer func() { _ = redisdao.Unlock(ctx, lockKey, lockVal) }()

	// 白名单判断：仅「退款成功」才回退权益；空串/未知/中间状态仅记录，防止误回退
	// （退款推送按官方文档在退款完成时触发，状态枚举联调时以官方为准）。
	if refund.RefundStatus != wechat.XPayRefundStatusSuccess {
		slog.WarnContext(ctx, "xpay refund notify not success, skip revoke",
			"order_no", refund.OutTradeNo, "refund_status", refund.RefundStatus)
		return nil
	}

	order, gerr := s.orderDao.OrderGetByOrderNo(ctx, refund.OutTradeNo)
	if gerr != nil {
		if isNotFound(gerr) {
			slog.ErrorContext(ctx, "xpay refund: order not found", "out_trade_no", refund.OutTradeNo)
			return nil
		}
		return errcode.DatabaseError
	}
	// 已终态则幂等返回。
	if order.OrderStatus == OrderStatusRefunded {
		return nil
	}

	// 订单真实性反查：退款推送无签名，回退权益前必须反查微信侧确认真实退款，
	// 防止伪造退款推送回收权益；未通过返回错误 -> 应答 ErrCode:1，微信重试。
	if verr := s.verifyXPayRefund(ctx, order, refund); verr != nil {
		return verr
	}

	// settleRefundSuccess 内部含条件流转（Paid -> Refunded），重复推送不会重复回退。
	s.settleRefundSuccess(ctx, order, refund.RefundFee)
	return nil
}

// handleIOSRefundQuery 处理 iOS 退款问询（3 秒内应答，仅本地查询）。
// 按权益使用情况细化：权益已消耗则拒绝退款（result_code=1 + evidence），未消耗则建议退款；
// 建议退款后权益由后续退款推送 settleRefundSuccess 回收（回收链路保证「已消耗部分不回退」）。
func (s *OrderService) handleIOSRefundQuery(ctx context.Context, query *wechat.XPayIOSRefundQueryNotify) []byte {
	order, err := s.orderDao.OrderGetByOrderNo(ctx, query.OutTradeNo)
	if err != nil {
		slog.ErrorContext(ctx, "xpay ios refund query: order not found", "out_trade_no", query.OutTradeNo, "error", err)
		return wechat.BuildIOSRefundQueryResponse(1, "拒绝退款",
			"订单号 "+query.OutTradeNo+" 在本地无记录，无法确认权益使用情况，拒绝退款")
	}
	// 已退款：款项已退回，再次建议退款会造成重复退款资损。
	if order.OrderStatus == OrderStatusRefunded {
		return wechat.BuildIOSRefundQueryResponse(1, "拒绝退款",
			"订单 "+order.OrderNo+" 已处于已退款状态，不支持重复退款")
	}
	// 权益已消耗则拒绝退款，防止「已使用权益后白嫖退款」。
	if s.iosRefundBenefitsConsumed(ctx, order) {
		return wechat.BuildIOSRefundQueryResponse(1, "拒绝退款",
			"订单 "+order.OrderNo+" 发放的权益已被使用（上传额度已消耗或会员已生效），不支持退款")
	}
	return wechat.BuildIOSRefundQueryResponse(0, "建议退款",
		"订单 "+order.OrderNo+" 发放的权益尚未使用，建议退款")
}

// iosRefundBenefitsConsumed 判断订单发放的权益是否已被消耗（用于 iOS 退款问询拒绝策略）。
// 额度类：Cos 凭证已用 >0 视为已消耗；会员类：会员已生效（在有效期内）视为已使用。
func (s *OrderService) iosRefundBenefitsConsumed(ctx context.Context, order *mysqlmodel.Order) bool {
	// 额度类：该订单发放的 Cos 凭证已消耗则视为已使用。
	if order.CosQuota > 0 {
		grants, err := mysqldao.NewQuotaGrantDao().QuotaGrantListByUserIDAndType(ctx, order.UserID, QuotaTypeCos)
		if err == nil {
			for _, g := range grants {
				if g.RefID == order.OrderNo && g.Used > 0 {
					return true
				}
			}
		}
	}
	// 会员类：会员已生效（vip_expire 在未来且非非会员），说明用户已开始享受会员权益。
	if order.MemberDays > 0 {
		if user, err := s.userDao.UserGetByID(ctx, order.UserID); err == nil {
			if user.VIPExpire > nowUnix() && user.VIPType != VIPTypeNone {
				return true
			}
		}
	}
	return false
}

// finalizeVirtualPaidOrder 虚拟支付发货：记录支付信息、发放权益并发送通知。
// paidTime/transactionID 由调用方提供：推送路径取推送报文，查单补偿路径取 query_order 结果。
func (s *OrderService) finalizeVirtualPaidOrder(ctx context.Context, order *mysqlmodel.Order, paidTime int64, transactionID, raw string) {
	_ = s.orderDao.OrderUpdateByOrderNo(ctx, order.OrderNo, map[string]any{
		"pay_time":       resolvePaidTime(paidTime),
		"transaction_id": transactionID,
		"callback_raw":   raw,
	})

	s.grantOrderBenefits(ctx, order)

	sendNotification(ctx, order.UserID, 0, NotificationTypeOrder, "订单支付成功", "你购买的「"+order.GoodsName+"」已到账")
}

// resolvePaidTime 兜底支付时间：推送字段缺失/非法（<=0）时用当前时间，避免 pay_time 写入 0。
func resolvePaidTime(paidTime int64) int64 {
	if paidTime <= 0 {
		return nowUnix()
	}
	return paidTime
}