package refund

import (
	"context"
	"math"
	"math/big"
	"slices"
	"strconv"

	"go.uber.org/zap"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"

	"github.com/break/junhong_cmp_fiber/internal/infrastructure/audit"
	"github.com/break/junhong_cmp_fiber/internal/model"
	"github.com/break/junhong_cmp_fiber/pkg/auditcontext"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
)

// clawbackAllocation 是一条原佣金的回溯分摊结果。
// Amount 为正的应回溯金额；写入回溯明细时取负数，原佣金记录本身不变。
type clawbackAllocation struct {
	Commission model.CommissionRecord
	Amount     int64
}

// clawbackCommission 处理一次退款的佣金回溯后处理。
//
// 返回非 nil 表示后处理尚未闭合（准入未满足或订单佣金未终态），由既有 Outbox / 补偿任务重试；
// 返回 nil 表示已闭合：已生成回溯明细、确认无需回溯或审批异常转人工。
//
// 准入由退款申请状态、审批异常标记与退款方式唯一决定：
// 仅退款申请已通过（原路退款还须渠道明确成功）且无审批异常时生成回溯明细。
// 失败分类标记面向「尝试是否终结」，与「退款是否真正完成」正交，因此不参与准入判定。
func (s *Service) clawbackCommission(ctx context.Context, refundID uint) error {
	var refund model.RefundRequest
	if err := s.db.WithContext(ctx).Where("id = ?", refundID).First(&refund).Error; err != nil {
		return errors.Wrap(errors.CodeDatabaseError, err, "查询退款单失败")
	}
	ctx = auditcontext.With(ctx, auditcontext.Context{
		ActorKind: constants.AuditActorSystemTask, ActorID: constants.AuditActorIDRefundCommissionPostProcessing,
		ActorName: "退款佣金自动回扣任务", Source: constants.AuditSourceWorker, CorrelationID: refund.RefundNo,
	})
	// commission_deducted 只是投影：已闭合即无需重复处理，本函数不依赖它做逐条幂等判定。
	if refund.CommissionDeducted {
		return nil
	}
	// 审批异常（企业微信通过后撤销）不生成任何回溯事实，但必须闭合后处理并转人工，
	// 否则补偿扫描会在每轮重复处理同一批退款单。
	if refund.AnomalyFlag != 0 {
		return s.settleClawback(ctx, &refund, constants.AuditActionRefundAnomalyFlagged,
			"退款审批异常，佣金回溯转人工处理", clawbackEventID(refund.ID, "clawback-anomaly"),
			map[string]any{
				"anomaly_flag": refund.AnomalyFlag, "anomaly_reason": refund.AnomalyReason,
				"order_id": refund.OrderID, "clawback_required": false,
			})
	}
	// 准入：只有已通过的退款才可能完成退款，待审批、原路处理中与渠道明确失败都必须等待。
	if refund.Status != model.RefundStatusApproved {
		return errors.New(errors.CodeServiceUnavailable, "退款申请尚未通过，暂不生成佣金回溯")
	}
	if refund.Method == constants.RefundMethodOriginalRoute && refund.ChannelRefundStatus != constants.RefundChannelStatusSucceeded {
		return errors.New(errors.CodeServiceUnavailable, "原路退款渠道结果尚未明确成功，暂不生成佣金回溯")
	}

	// 订单佣金未终态时等待：此时「无已发放佣金」只代表尚未计算完成或尚待人工修正，
	// 提前判定为无需回溯会让后续入账的佣金永久失去回溯机会，违反「MUST NOT 提前判定为无需回溯」。
	//
	// 终态由两件事共同决定，缺一不可：
	//   1. 订单佣金流程已离开「待计算」；
	//   2. 该订单不存在任何未终态佣金记录（已冻结 1、解冻中 2、待人工修正 99）。
	// 不能用 order.commission_status = 3 判定终态：该值只表示「存在 99 记录」，
	// 而人工处置（shop_commission.ResolveCommissionRecord）把 99 改成已发放/已失效后并不回写订单状态，
	// 订单会长期停在 3；只看订单状态会把「待人工修正」误判为终态并提前闭合。
	//
	// 收敛条件（依据全仓 tb_commission_record.status 写点实测）：该表状态只由
	// commission_calculation（创建置 3 或 99、入账置 3）、recharge_order（创建置 3）与
	// shop_commission.ResolveCommissionRecord（人工处置置 3 或 4）写入，从不写入 1/2
	// ——1/2 是仅供历史数据读取的遗留枚举，纳入未终态集合属防御性判断。
	// 因此现实中的等待只可能由 99 引起，且处置后必然收敛：置 3 → 生成回溯；置 4 → 确认无佣金可回溯并闭合。
	var order model.Order
	if err := s.db.WithContext(ctx).Select("id, commission_status").First(&order, refund.OrderID).Error; err != nil {
		return errors.Wrap(errors.CodeDatabaseError, err, "查询退款佣金关联订单失败")
	}
	if order.CommissionStatus == model.CommissionStatusPending {
		return errors.New(errors.CodeServiceUnavailable, "订单佣金尚未计算完成，等待终态后再回溯")
	}
	var openCommissionCount int64
	if err := s.db.WithContext(ctx).Model(&model.CommissionRecord{}).
		Where("order_id = ? AND status IN ?", refund.OrderID, []int{
			constants.CommissionStatusFrozen,
			constants.CommissionStatusUnfreezing,
			constants.CommissionStatusPendingReview,
		}).Count(&openCommissionCount).Error; err != nil {
		return errors.Wrap(errors.CodeDatabaseError, err, "统计订单未终态佣金记录失败")
	}
	if openCommissionCount > 0 {
		return errors.New(errors.CodeServiceUnavailable, "订单存在未终态佣金记录，等待终态后再回溯")
	}

	// 可回溯原佣金固定为已发放记录，稳定顺序取 original_commission_id 升序：
	// 该顺序决定舍入补差落点，必须固定，否则同一输入可能得出不同分摊结果。
	var commissions []model.CommissionRecord
	if err := s.db.WithContext(ctx).
		Where("order_id = ? AND status = ?", refund.OrderID, constants.CommissionStatusReleased).
		Order("id ASC").Find(&commissions).Error; err != nil {
		return errors.Wrap(errors.CodeDatabaseError, err, "查询退款原佣金记录失败")
	}
	if len(commissions) == 0 {
		// 终态确无佣金：不产生任何钱包变动。
		return s.settleClawback(ctx, &refund, constants.AuditActionRefundClawbackNotRequired,
			"退款无需回溯佣金", clawbackEventID(refund.ID, "clawback-not-required"),
			map[string]any{
				"order_id": refund.OrderID, "commission_status": order.CommissionStatus,
				"released_commission_count": 0, "clawback_required": false,
			})
	}

	denominator, err := s.resolveClawbackDenominator(ctx, &refund)
	if err != nil {
		return err
	}
	numerator := s.resolveClawbackNumerator(&refund)
	if denominator <= 0 {
		// 冻结实收缺失或非正：记录可恢复失败，不落库、不改余额、不置位，
		// 禁止用订单标价或申请金额替代。
		s.logger.Error("佣金回溯：本次退款冻结实收金额非正，等待权威金额补齐",
			zap.Uint("refund_id", refund.ID), zap.String("refund_no", refund.RefundNo),
			zap.Int64("frozen_actual_received_amount", refund.FrozenActualReceivedAmount))
		return errors.New(errors.CodeServiceUnavailable, "退款冻结实收金额缺失或非正，无法计算佣金回溯")
	}
	if numerator <= 0 {
		// 已通过的退款必然携带权威成功退款金额；缺失时同样按可恢复失败处理，不生成零金额回溯。
		s.logger.Error("佣金回溯：本次退款成功金额非正，等待权威金额补齐",
			zap.Uint("refund_id", refund.ID), zap.String("refund_no", refund.RefundNo),
			zap.String("method", refund.Method), zap.Int64("channel_refund_amount", refund.ChannelRefundAmount))
		return errors.New(errors.CodeServiceUnavailable, "退款成功金额缺失或非正，无法计算佣金回溯")
	}

	// 剩余可回溯余额按明细聚合：同一原佣金可被同订单的多次退款累计回溯，累计不得超过原佣金金额。
	clawed, err := s.loadClawedAmounts(ctx, commissions)
	if err != nil {
		return err
	}
	amounts := make([]int64, len(commissions))
	clawedAmounts := make([]int64, len(commissions))
	for i := range commissions {
		amounts[i] = commissions[i].Amount
		clawedAmounts[i] = clawed[commissions[i].ID]
	}
	amountsAllocated := allocateClawbackAmounts(amounts, clawedAmounts, numerator, denominator)

	allocations := make([]clawbackAllocation, 0, len(commissions))
	total := int64(0)
	for i := range commissions {
		allocations = append(allocations, clawbackAllocation{Commission: commissions[i], Amount: amountsAllocated[i]})
		total += amountsAllocated[i]
	}
	if total <= 0 {
		// 比例向下取整后为 0，或全部原佣金的剩余可回溯余额已用尽：本次退款不再产生资金事实。
		return s.settleClawback(ctx, &refund, constants.AuditActionRefundClawbackNotRequired,
			"退款无需回溯佣金", clawbackEventID(refund.ID, "clawback-not-required"),
			map[string]any{
				"order_id": refund.OrderID, "commission_status": order.CommissionStatus,
				"released_commission_count": len(commissions), "clawback_required": false,
				"numerator": numerator, "denominator": denominator,
			})
	}

	return s.applyClawback(ctx, &refund, allocations)
}

// clawbackEventID 生成回溯审计事件的稳定键，重复执行返回同一事件，审计写入因此天然幂等。
func clawbackEventID(refundID uint, suffix string) string {
	return "refund:" + strconv.FormatUint(uint64(refundID), 10) + ":" + suffix
}

// resolveClawbackDenominator 取本次退款的冻结实收金额作为回溯比例分母。
// 退款行缺失权威金额时回落本次审批尝试记录的冻结事实；两者都没有时返回 0，由调用方按可恢复失败处理。
func (s *Service) resolveClawbackDenominator(ctx context.Context, refund *model.RefundRequest) (int64, error) {
	if refund.FrozenActualReceivedAmount > 0 {
		return refund.FrozenActualReceivedAmount, nil
	}
	if refund.LatestAttemptID == 0 {
		return 0, nil
	}
	var attempt model.RefundRequestAttempt
	err := s.db.WithContext(ctx).Select("id, frozen_actual_received_amount").
		First(&attempt, refund.LatestAttemptID).Error
	if err == nil {
		return attempt.FrozenActualReceivedAmount, nil
	}
	if err == gorm.ErrRecordNotFound {
		return 0, nil
	}
	return 0, errors.Wrap(errors.CodeDatabaseError, err, "查询退款审批尝试冻结实收金额失败")
}

// resolveClawbackNumerator 取本次退款成功金额作为回溯比例分子。
// 原路退款取渠道明确成功金额，其余方式取审批退款金额（含退回原钱包与客户收款信息方式）。
func (s *Service) resolveClawbackNumerator(refund *model.RefundRequest) int64 {
	if refund.Method == constants.RefundMethodOriginalRoute {
		return refund.ChannelRefundAmount
	}
	if refund.ApprovedRefundAmount != nil {
		return *refund.ApprovedRefundAmount
	}
	return 0
}

// loadClawedAmounts 聚合各原佣金已生成的回溯累计金额（正数视图）。
// 累计口径覆盖全部退款单：同一原佣金的累计回溯不得超过其金额，与具体退款无关。
func (s *Service) loadClawedAmounts(ctx context.Context, commissions []model.CommissionRecord) (map[uint]int64, error) {
	clawed := make(map[uint]int64, len(commissions))
	if len(commissions) == 0 {
		return clawed, nil
	}
	ids := make([]uint, 0, len(commissions))
	for i := range commissions {
		ids = append(ids, commissions[i].ID)
	}
	type clawedRow struct {
		OriginalCommissionID uint
		Total                int64
	}
	var rows []clawedRow
	if err := s.db.WithContext(ctx).Model(&model.CommissionClawbackRecord{}).
		Select("original_commission_id, COALESCE(SUM(amount), 0) AS total").
		Where("original_commission_id IN ?", ids).
		Group("original_commission_id").Scan(&rows).Error; err != nil {
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "聚合原佣金已回溯金额失败")
	}
	for _, row := range rows {
		// 明细金额为负数，转为正数视图供分摊计算使用。
		clawed[row.OriginalCommissionID] = -row.Total
	}
	return clawed, nil
}

// allocateClawbackAmounts 按分计算各原佣金的应回溯金额，入参与返回均按 original_commission_id 升序。
//
// 计算规则：
//   - 逐条基准 base_i = min(floor(amount_i × N / D), 剩余_i)；
//   - 应回溯总额 T = min(floor(Σamount_i × N / D), Σ剩余_i)；
//   - 舍入差 T − Σbase_i 自稳定顺序末条起向前分摊，每条不超过该条剩余_i。
//
// 乘法使用 math/big 中间量，全程整数，禁止浮点与溢出；余额不足由调用方允许负余额，不在此处裁剪。
func allocateClawbackAmounts(amounts []int64, clawed []int64, numerator int64, denominator int64) []int64 {
	result := make([]int64, len(amounts))
	if len(amounts) == 0 || numerator <= 0 || denominator <= 0 {
		return result
	}
	remaining := make([]int64, len(amounts))
	totalAmount := new(big.Int)
	totalRemaining := new(big.Int)
	for i := range amounts {
		left := amounts[i] - clawed[i]
		if amounts[i] <= 0 {
			left = 0
		}
		if left < 0 {
			left = 0
		}
		remaining[i] = left
		totalAmount.Add(totalAmount, big.NewInt(amounts[i]))
		totalRemaining.Add(totalRemaining, big.NewInt(left))
	}

	totalTarget := mulDivFloor(totalAmount, numerator, denominator)
	totalTarget = minBig(totalTarget, totalRemaining)

	totalBase := new(big.Int)
	for i := range amounts {
		base := mulDivFloorInt64(amounts[i], numerator, denominator)
		if base > remaining[i] {
			base = remaining[i]
		}
		result[i] = base
		totalBase.Add(totalBase, big.NewInt(base))
	}

	// 补差自末条起向前分摊；最末条不足以吸收全部余差时继续向前一条分摊。
	gap := new(big.Int).Sub(totalTarget, totalBase)
	for i := len(amounts) - 1; i >= 0 && gap.Sign() > 0; i-- {
		room := remaining[i] - result[i]
		if room <= 0 {
			continue
		}
		add := minBig(gap, big.NewInt(room))
		result[i] += add.Int64()
		gap.Sub(gap, add)
	}
	return result
}

// mulDivFloor 计算 floor(value × numerator / denominator)，使用大整数中间量避免溢出。
func mulDivFloor(value *big.Int, numerator int64, denominator int64) *big.Int {
	if value.Sign() <= 0 || numerator <= 0 || denominator <= 0 {
		return big.NewInt(0)
	}
	product := new(big.Int).Mul(value, big.NewInt(numerator))
	return product.Div(product, big.NewInt(denominator))
}

// mulDivFloorInt64 计算 floor(value × numerator / denominator) 并收敛到 int64。
// 结果不可能为负；超过 int64 上限时按上限收敛，由后续剩余额度裁剪兜底。
func mulDivFloorInt64(value int64, numerator int64, denominator int64) int64 {
	result := mulDivFloor(big.NewInt(value), numerator, denominator)
	if !result.IsInt64() {
		return math.MaxInt64
	}
	return result.Int64()
}

// minBig 返回两个非负大整数中的较小值。
func minBig(left *big.Int, right *big.Int) *big.Int {
	if left.Cmp(right) <= 0 {
		return new(big.Int).Set(left)
	}
	return new(big.Int).Set(right)
}

// settleClawback 在没有资金动作时闭合退款佣金后处理：条件置位完成后处理事实并写入同一事务的审计。
// 置位带 commission_deducted = false 保护，重复执行不会二次闭合。
func (s *Service) settleClawback(
	ctx context.Context,
	refund *model.RefundRequest,
	actionCode string,
	summary string,
	eventID string,
	metadata map[string]any,
) error {
	if s.auditWriter == nil {
		return errors.New(errors.CodeInvalidStatus, "退款统一审计接缝未配置")
	}
	err := s.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		result := tx.WithContext(ctx).Model(&model.RefundRequest{}).
			Where("id = ? AND commission_deducted = ?", refund.ID, false).
			Update("commission_deducted", true)
		if result.Error != nil {
			return errors.Wrap(errors.CodeDatabaseError, result.Error, "标记退款佣金后处理已闭合失败")
		}
		if result.RowsAffected == 0 {
			return nil
		}
		primary := audit.RefundResource(refund, constants.AuditResourceRelationPrimary, constants.AuditResourceRoleRefundTarget)
		primary.BeforeData = map[string]any{"commission_deducted": false}
		primary.AfterData = map[string]any{"commission_deducted": true}
		primary.SubjectVisibility = constants.AuditSubjectResult
		primary.SubjectSummary = summary
		resources := []audit.ResourceInput{primary}
		var order model.Order
		if err := tx.WithContext(ctx).First(&order, refund.OrderID).Error; err != nil {
			return errors.Wrap(errors.CodeDatabaseError, err, "查询退款佣金关联订单审计快照失败")
		}
		orderResource := audit.OrderResource(&order, constants.AuditResourceRelationReference, constants.AuditResourceRoleRefundOrder)
		orderResource.SubjectVisibility = constants.AuditSubjectInternalOnly
		resources = append(resources, orderResource)
		if _, err := s.auditWriter.AppendAndGet(ctx, tx, audit.AppendInput{
			EventID: eventID, ActionCode: actionCode, Summary: summary,
			ScopeType: constants.AuditScopePlatform, Result: constants.AuditResultSuccess,
			CorrelationID: refund.RefundNo, Metadata: metadata, Resources: resources,
		}); err != nil {
			return errors.Wrap(errors.CodeDatabaseError, err, "写入退款佣金后处理闭合审计失败")
		}
		return nil
	})
	if err != nil {
		return err
	}
	s.logger.Info("退款佣金回溯后处理已闭合",
		zap.Uint("refund_id", refund.ID), zap.String("refund_no", refund.RefundNo), zap.String("action", actionCode))
	return nil
}

// clawbackShopState 记录一个店铺在本次回溯中的钱包与资金事实，用于同事务审计。
type clawbackShopState struct {
	shop        model.Shop
	wallet      model.AgentWallet
	balanceFrom int64
	balanceTo   int64
}

// applyClawback 在同一事务内释放待审提现冻结、生成回溯明细、扣减佣金钱包并写入审计。
//
// 事务内顺序固定：锁提现申请行 → 锁尝试行 → 解冻冻结 → 置驳回 → 插回溯明细 → 扣 balance（允许为负）
// → 写负数流水 → 审计。任一步失败整体回滚，不释放提现、不写部分明细或部分流水。
func (s *Service) applyClawback(ctx context.Context, refund *model.RefundRequest, allocations []clawbackAllocation) error {
	if s.auditWriter == nil {
		return errors.New(errors.CodeInvalidStatus, "退款统一审计接缝未配置")
	}
	// generatedCount 记录本次实际落库的明细条数，用于日志与审计的真实性（不含命中唯一键跳过的条目）。
	generatedCount := 0
	err := s.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		// 第 2 层幂等：锁定原佣金行并复核状态，状态被并发改写即整体回滚等待重试。
		ids := make([]uint, 0, len(allocations))
		for i := range allocations {
			ids = append(ids, allocations[i].Commission.ID)
		}
		var locked []model.CommissionRecord
		if err := tx.WithContext(ctx).Clauses(clause.Locking{Strength: "UPDATE"}).
			Where("id IN ?", ids).Order("id ASC").Find(&locked).Error; err != nil {
			return errors.Wrap(errors.CodeDatabaseError, err, "锁定退款原佣金记录失败")
		}
		statusByID := make(map[uint]int, len(locked))
		for i := range locked {
			statusByID[locked[i].ID] = locked[i].Status
		}
		for i := range allocations {
			if statusByID[allocations[i].Commission.ID] != constants.CommissionStatusReleased {
				return errors.New(errors.CodeConflict, "退款原佣金状态已变化")
			}
		}

		// 第 1 层幂等的事实来源是 (refund_id, original_commission_id) 唯一约束；
		// 这里按已有明细跳过已生成的条目，避免唯一冲突回滚整次后处理的其余资金事实。
		var existing []model.CommissionClawbackRecord
		if err := tx.WithContext(ctx).Where("refund_id = ?", refund.ID).Find(&existing).Error; err != nil {
			return errors.Wrap(errors.CodeDatabaseError, err, "查询退款已有佣金回溯明细失败")
		}
		generated := make(map[uint]struct{}, len(existing))
		for i := range existing {
			generated[existing[i].OriginalCommissionID] = struct{}{}
		}

		// 按店铺分组并按店铺升序加锁，避免与并发回溯或提现终态消费者形成死锁环。
		shopOrder := make([]uint, 0, len(allocations))
		shopIndex := make(map[uint][]int, len(allocations))
		for i := range allocations {
			shopID := allocations[i].Commission.ShopID
			if _, ok := shopIndex[shopID]; !ok {
				shopOrder = append(shopOrder, shopID)
			}
			shopIndex[shopID] = append(shopIndex[shopID], i)
		}
		sortUintAsc(shopOrder)

		var (
			records      []*model.CommissionClawbackRecord
			transactions []*model.AgentWalletTransaction
			shops        []clawbackShopState
		)
		remark := "退款佣金回溯"
		for _, shopID := range shopOrder {
			// 加锁顺序全库统一：申请行 → 尝试行 → 钱包行（钱包永远最后加锁）。
			rejects, err := s.collectPendingWithdrawalRejects(ctx, tx, shopID)
			if err != nil {
				return err
			}
			var wallet model.AgentWallet
			if err := tx.WithContext(ctx).Clauses(clause.Locking{Strength: "UPDATE"}).
				Where("shop_id = ? AND wallet_type = ?", shopID, constants.AgentWalletTypeCommission).
				First(&wallet).Error; err != nil {
				return errors.Wrap(errors.CodeDatabaseError, err, "锁定退款佣金钱包失败")
			}
			// 先释放待审核提现冻结，再扣减余额：既有约束要求冻结额不高于非负余额。
			if err := s.applyPendingWithdrawalRejects(ctx, tx, &wallet, refund, rejects); err != nil {
				return err
			}
			balanceFrom := wallet.Balance
			for _, index := range shopIndex[shopID] {
				allocation := allocations[index]
				if allocation.Amount <= 0 {
					continue
				}
				if _, ok := generated[allocation.Commission.ID]; ok {
					continue
				}
				commissionID := allocation.Commission.ID
				record := &model.CommissionClawbackRecord{
					RefundID: refund.ID, OriginalCommissionID: commissionID,
					OrderID: allocation.Commission.OrderID, ShopID: allocation.Commission.ShopID,
					OrderNo: refund.OrderNo, RefundNo: refund.RefundNo,
					CommissionSource: allocation.Commission.CommissionSource,
					Amount:           -allocation.Amount, BalanceAfter: wallet.Balance - allocation.Amount,
					Withdrawable: false, Status: constants.CommissionStatusClawback,
				}
				if err := tx.WithContext(ctx).Create(record).Error; err != nil {
					return errors.Wrap(errors.CodeDatabaseError, err, "创建佣金回溯明细失败")
				}
				// 佣金钱包允许余额为负：余额不足不跳过、不拒绝回溯。
				result := tx.WithContext(ctx).Model(&model.AgentWallet{}).
					Where("id = ? AND version = ?", wallet.ID, wallet.Version).
					Updates(map[string]any{"balance": gorm.Expr("balance - ?", allocation.Amount), "version": gorm.Expr("version + 1")})
				if result.Error != nil {
					return errors.Wrap(errors.CodeDatabaseError, result.Error, "扣减退款佣金钱包失败")
				}
				if result.RowsAffected != 1 {
					return errors.New(errors.CodeConflict, "退款佣金钱包版本已变化")
				}
				balanceBefore := wallet.Balance
				wallet.Balance -= allocation.Amount
				wallet.Version++
				refType, refID := constants.ReferenceTypeCommission, commissionID
				transaction := &model.AgentWalletTransaction{
					AgentWalletID: wallet.ID, ShopID: wallet.ShopID, UserID: refund.Creator,
					TransactionType: constants.AgentTransactionTypeCommissionDeduct, Amount: -allocation.Amount,
					BalanceBefore: balanceBefore, BalanceAfter: wallet.Balance,
					Status: constants.TransactionStatusSuccess, ReferenceType: &refType, ReferenceID: &refID,
					Remark: &remark, Creator: refund.Creator, ShopIDTag: wallet.ShopID,
				}
				if err := tx.WithContext(ctx).Create(transaction).Error; err != nil {
					return errors.Wrap(errors.CodeDatabaseError, err, "创建退款佣金回溯流水失败")
				}
				records = append(records, record)
				transactions = append(transactions, transaction)
				generatedCount++
			}
			var shop model.Shop
			if err := tx.WithContext(ctx).First(&shop, shopID).Error; err != nil {
				return errors.Wrap(errors.CodeDatabaseError, err, "查询退款佣金关联店铺审计快照失败")
			}
			shops = append(shops, clawbackShopState{shop: shop, wallet: wallet, balanceFrom: balanceFrom, balanceTo: wallet.Balance})
		}

		// 本次未生成任何明细时（全部命中已存在的唯一键，仅投影陈旧时可达成）不写
		// refund.clawback_commission 审计：该动作语义是「生成回溯明细」，
		// 记录数 0 且 clawback_required=true 的审计是误导性事实。置位逻辑保持不变。
		if len(records) > 0 {
			if err := s.appendClawbackAudit(ctx, tx, refund, records, transactions, shops); err != nil {
				return err
			}
		}
		// 全部回溯明细与钱包流水完成后才置位；带条件保护，重复执行不会二次闭合。
		result := tx.WithContext(ctx).Model(&model.RefundRequest{}).
			Where("id = ? AND commission_deducted = ?", refund.ID, false).
			Update("commission_deducted", true)
		if result.Error != nil {
			return errors.Wrap(errors.CodeDatabaseError, result.Error, "标记退款佣金回溯完成失败")
		}
		if result.RowsAffected != 1 {
			return errors.New(errors.CodeConflict, "退款佣金后处理已由其他执行闭合")
		}
		return nil
	})
	if err != nil {
		return err
	}
	s.logger.Info("退款佣金回溯完成",
		zap.Uint("refund_id", refund.ID), zap.String("refund_no", refund.RefundNo),
		zap.Int("clawback_records", generatedCount))
	return nil
}

// appendClawbackAudit 将回溯明细、佣金钱包与负数流水绑定在同一事务。
func (s *Service) appendClawbackAudit(
	ctx context.Context,
	tx *gorm.DB,
	refund *model.RefundRequest,
	records []*model.CommissionClawbackRecord,
	transactions []*model.AgentWalletTransaction,
	shops []clawbackShopState,
) error {
	primary := audit.RefundResource(refund, constants.AuditResourceRelationPrimary, constants.AuditResourceRoleRefundTarget)
	primary.SubjectVisibility = constants.AuditSubjectResult
	primary.SubjectSummary = "退款佣金已回溯"
	resources := []audit.ResourceInput{primary}
	var order model.Order
	if err := tx.WithContext(ctx).First(&order, refund.OrderID).Error; err != nil {
		return errors.Wrap(errors.CodeDatabaseError, err, "查询退款佣金关联订单审计快照失败")
	}
	orderResource := audit.OrderResource(&order, constants.AuditResourceRelationReference, constants.AuditResourceRoleRefundOrder)
	orderResource.SubjectVisibility = constants.AuditSubjectInternalOnly
	resources = append(resources, orderResource)

	totalClawback := int64(0)
	for _, record := range records {
		totalClawback += record.Amount
		resource := audit.CommissionClawbackResource(record)
		resource.SubjectVisibility = constants.AuditSubjectInternalOnly
		resources = append(resources, resource)
	}
	for i := range transactions {
		resource := audit.AgentWalletTransactionResource(transactions[i], constants.AuditResourceRelationAffected, constants.AuditResourceRoleRefundTransaction)
		resource.SubjectVisibility = constants.AuditSubjectInternalOnly
		resources = append(resources, resource)
	}
	for i := range shops {
		walletResource := audit.AgentWalletResource(&shops[i].wallet, constants.AuditResourceRelationAffected, constants.AuditResourceRoleRefundWallet,
			map[string]any{"balance": shops[i].balanceFrom}, map[string]any{"balance": shops[i].balanceTo})
		walletResource.SubjectVisibility = constants.AuditSubjectInternalOnly
		resources = append(resources, walletResource)
		shopResource := audit.ShopResource(&shops[i].shop, constants.AuditResourceRelationReference, constants.AuditResourceRoleRefundCommission)
		shopResource.SubjectVisibility = constants.AuditSubjectInternalOnly
		resources = append(resources, shopResource)
	}

	_, err := s.auditWriter.AppendAndGet(ctx, tx, audit.AppendInput{
		EventID: clawbackEventID(refund.ID, "clawback"), ActionCode: constants.AuditActionRefundClawbackCommission,
		Summary: "生成退款佣金回溯明细", ScopeType: constants.AuditScopePlatform, Result: constants.AuditResultSuccess,
		CorrelationID: refund.RefundNo,
		Metadata: map[string]any{
			"order_id": refund.OrderID, "clawback_record_count": len(records),
			"clawback_total_amount": totalClawback, "clawback_required": true,
		},
		Resources: resources,
	})
	if err != nil {
		return errors.Wrap(errors.CodeDatabaseError, err, "写入退款佣金回溯审计失败")
	}
	return nil
}

// sortUintAsc 就地对店铺 ID 升序排序，保证多店铺加锁顺序稳定。
func sortUintAsc(values []uint) {
	slices.Sort(values)
}