package refund

import (
	"context"
	"strconv"
	"strings"

	"gorm.io/gorm"
	"gorm.io/gorm/clause"

	approvalapp "github.com/break/junhong_cmp_fiber/internal/application/approval"
	"github.com/break/junhong_cmp_fiber/internal/infrastructure/commissiondelivery"
	"github.com/break/junhong_cmp_fiber/internal/infrastructure/messaging/outbox"
	"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"
)

// Handle 幂等处理退款的渠道无关审批终态。
func (s *Service) Handle(ctx context.Context, event approvalapp.TerminalDecisionEvent) error {
	if s == nil || s.db == nil || event.BusinessType != constants.ApprovalBusinessTypeRefund ||
		event.BusinessID == 0 || event.InstanceID == 0 {
		return errors.New(errors.CodeInvalidParam, "退款审批终态参数无效")
	}
	switch event.Decision {
	case constants.ApprovalDecisionApproved:
		return s.applyApprovedDecision(ctx, event)
	case constants.ApprovalDecisionRejected, constants.ApprovalDecisionCancelled, constants.ApprovalDecisionDeleted:
		return s.applyClosedDecision(ctx, event)
	case constants.ApprovalDecisionRevokedAfterApproved:
		return nil
	default:
		return errors.New(errors.CodeInvalidParam, "不支持的退款审批终态")
	}
}

func (s *Service) applyApprovedDecision(ctx context.Context, event approvalapp.TerminalDecisionEvent) error {
	ctx = auditcontext.With(ctx, auditcontext.Context{CorrelationID: event.CorrelationID, ParentEventID: event.EventID})
	var refund model.RefundRequest
	var order model.Order
	changed := false
	err := s.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		if err := tx.WithContext(ctx).Clauses(clause.Locking{Strength: "UPDATE"}).Where("id = ?", event.BusinessID).First(&refund).Error; err != nil {
			if err == gorm.ErrRecordNotFound {
				return errors.New(errors.CodeForbidden, "无权限操作该资源或资源不存在")
			}
			return errors.Wrap(errors.CodeDatabaseError, err, "锁定退款申请失败")
		}
		if refund.ApprovalInstanceID == nil || *refund.ApprovalInstanceID != event.InstanceID {
			return errors.New(errors.CodeConflict, "退款申请关联的审批实例不一致")
		}
		if refund.Status != model.RefundStatusPending && refund.Status != model.RefundStatusApproved {
			return errors.New(errors.CodeInvalidStatus, "退款申请状态不允许审批通过")
		}
		if err := tx.WithContext(ctx).Clauses(clause.Locking{Strength: "UPDATE"}).Where("id = ?", refund.OrderID).First(&order).Error; err != nil {
			return errors.Wrap(errors.CodeDatabaseError, err, "锁定退款关联订单失败")
		}
		beforeRefund := refundAuditState(&refund)
		beforeOrder := map[string]any{"payment_status": order.PaymentStatus}
		approvedAmount := refund.RequestedRefundAmount
		if err := validateApprovedRefundAmount(approvedAmount, refund.RequestedRefundAmount, &order); err != nil {
			return err
		}
		if refund.Status == model.RefundStatusPending {
			changed = true
			result := tx.WithContext(ctx).Model(&model.RefundRequest{}).
				Where("id = ? AND status = ?", refund.ID, model.RefundStatusPending).
				Updates(map[string]any{
					"status": model.RefundStatusApproved, "processed_at": event.OccurredAt,
					"approved_refund_amount": approvedAmount, "remark": "企业微信审批通过",
					"updated_at": event.OccurredAt,
				})
			if result.Error != nil {
				return errors.Wrap(errors.CodeDatabaseError, result.Error, "完成退款审批申请失败")
			}
			if result.RowsAffected != 1 {
				return errors.New(errors.CodeConflict, "退款申请状态已变化")
			}
		}
		switch order.PaymentStatus {
		case model.PaymentStatusPaid:
			changed = true
			result := tx.WithContext(ctx).Model(&model.Order{}).
				Where("id = ? AND payment_status = ?", order.ID, model.PaymentStatusPaid).
				Updates(map[string]any{"payment_status": model.PaymentStatusRefunded, "updated_at": event.OccurredAt})
			if result.Error != nil {
				return errors.Wrap(errors.CodeDatabaseError, result.Error, "更新订单退款状态失败")
			}
			if result.RowsAffected != 1 {
				return errors.New(errors.CodeConflict, "订单退款状态已变化")
			}
			order.PaymentStatus = model.PaymentStatusRefunded
		case model.PaymentStatusRefunded:
		default:
			return errors.New(errors.CodeInvalidStatus, "订单状态不允许完成退款")
		}
		if err := s.refundWalletPayment(ctx, tx, &refund, &order, approvedAmount, event.SubmitterAccountID); err != nil {
			return err
		}
		if err := s.appendCompletedNotification(ctx, tx, &refund); err != nil {
			return err
		}
		if err := commissiondelivery.AppendRefundCommissionDeduct(ctx, tx, outbox.NewRepository(), refund.ID, refund.OrderID); err != nil {
			return err
		}
		if err := commissiondelivery.AppendRefundAssetProcess(ctx, tx, outbox.NewRepository(), refund.ID, refund.OrderID); err != nil {
			return err
		}
		if !changed {
			return nil
		}
		return s.appendRefundAudit(ctx, tx, refund.ID, constants.AuditActionRefundApproved, "通过退款审批",
			"refund:"+strconv.FormatUint(uint64(refund.ID), 10)+":approved", beforeRefund, beforeOrder, "退款已通过")
	})
	if err != nil {
		s.recordRefundFailure(ctx, constants.AuditActionRefundApproved, "通过退款审批失败", &refund, &order, err)
		return err
	}
	return nil
}

func (s *Service) applyClosedDecision(ctx context.Context, event approvalapp.TerminalDecisionEvent) error {
	ctx = auditcontext.With(ctx, auditcontext.Context{CorrelationID: event.CorrelationID, ParentEventID: event.EventID})
	reason := map[string]string{
		constants.ApprovalDecisionRejected:  "企业微信审批已拒绝",
		constants.ApprovalDecisionCancelled: "企业微信审批已撤销",
		constants.ApprovalDecisionDeleted:   "企业微信审批已删除",
	}[event.Decision]
	var refund model.RefundRequest
	var order model.Order
	err := s.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		if err := tx.WithContext(ctx).Clauses(clause.Locking{Strength: "UPDATE"}).Where("id = ?", event.BusinessID).First(&refund).Error; err != nil {
			return errors.Wrap(errors.CodeDatabaseError, err, "锁定退款申请失败")
		}
		if refund.ApprovalInstanceID == nil || *refund.ApprovalInstanceID != event.InstanceID {
			return errors.New(errors.CodeConflict, "退款申请关联的审批实例不一致")
		}
		if refund.Status == model.RefundStatusRejected {
			return nil
		}
		if refund.Status != model.RefundStatusPending {
			return errors.New(errors.CodeInvalidStatus, "退款申请状态不允许结束审批")
		}
		if err := tx.WithContext(ctx).First(&order, refund.OrderID).Error; err != nil {
			return errors.Wrap(errors.CodeDatabaseError, err, "查询退款关联订单失败")
		}
		beforeRefund := refundAuditState(&refund)
		result := tx.WithContext(ctx).Model(&model.RefundRequest{}).
			Where("id = ? AND status = ?", refund.ID, model.RefundStatusPending).
			Updates(map[string]any{
				"status": model.RefundStatusRejected, "processed_at": event.OccurredAt,
				"reject_reason": strings.TrimSpace(reason), "updated_at": event.OccurredAt,
			})
		if result.Error != nil {
			return errors.Wrap(errors.CodeDatabaseError, result.Error, "结束退款审批申请失败")
		}
		if result.RowsAffected != 1 {
			return errors.New(errors.CodeConflict, "退款申请状态已变化")
		}
		return s.appendRefundAudit(ctx, tx, refund.ID, constants.AuditActionRefundRejected, "拒绝退款审批",
			"refund:"+strconv.FormatUint(uint64(refund.ID), 10)+":rejected", beforeRefund, nil, "退款已拒绝")
	})
	if err != nil {
		s.recordRefundFailure(ctx, constants.AuditActionRefundRejected, "拒绝退款审批失败", &refund, &order, err)
	}
	return err
}

func (s *Service) ProcessCommissionDeduction(ctx context.Context, refundID uint) error {
	s.deductAllCommission(ctx, refundID)
	var refund model.RefundRequest
	if err := s.db.WithContext(ctx).Select("commission_deducted").First(&refund, refundID).Error; err != nil {
		return errors.Wrap(errors.CodeDatabaseError, err, "复核退款佣金回扣状态失败")
	}
	if !refund.CommissionDeducted {
		return errors.New(errors.CodeServiceUnavailable, "退款佣金回扣尚未完成")
	}
	return nil
}

func (s *Service) ProcessAssetPostProcessing(ctx context.Context, refundID uint) error {
	s.handleRefundAssetProcessing(ctx, refundID)
	var refund model.RefundRequest
	if err := s.db.WithContext(ctx).Select("asset_reset").First(&refund, refundID).Error; err != nil {
		return errors.Wrap(errors.CodeDatabaseError, err, "复核退款资产后处理状态失败")
	}
	if !refund.AssetReset {
		return errors.New(errors.CodeServiceUnavailable, "退款资产后处理尚未完成")
	}
	return nil
}

var _ approvalapp.BusinessDecisionHandler = (*Service)(nil)