package summary

import (
	"context"
	"errors"
	"time"

	"bsm/full/module/ec/order/internal/impl"
	"bsm/full/module/ec/order/internal/models"
	pb "bsm/full/module/ec/order/pb"

	"git.apinb.com/bsm-sdk/core/errcode"
	"git.apinb.com/bsm-sdk/core/printer"
	"git.apinb.com/bsm-sdk/core/service"
	"gorm.io/gorm"
)

// 取消订单
func Cancel(ctx context.Context, in *pb.CancelRequest) (reply *pb.OrderStatusReply, err error) {
	// parse authorization meta.
	_, err = service.ParseMetaCtx(ctx, nil)
	if err != nil {
		return nil, err
	}

	var (
		summary = new(models.OrderSummary)
	)

	err = impl.DBService.Where("order_no = ?", in.OrderNo).First(&summary).Error
	if err != nil {
		printer.Error(err.Error())
		return nil, errcode.ErrDB
	}

	// 状态机约束：只有"未支付"（status=1）的订单允许取消，其它状态拒绝，避免非法状态跃迁。
	if summary.Status != 1 {
		return nil, errcode.ErrUnavailable
	}

	details := make([]*models.OrderDetails, 0)
	err = impl.DBService.Transaction(func(tx *gorm.DB) error {
		// 1. 以状态为条件更新订单，避免并发下重复取消。
		result := tx.Model(&models.OrderSummary{}).Where("order_no = ? AND status = ?", in.OrderNo, 1).
			Updates(map[string]any{
				"status":          -1,
				"coupon_identity": "",
				"coupon_amount":   0,
			})
		if result.Error != nil {
			return result.Error
		}
		if result.RowsAffected == 0 {
			return errcode.ErrUnavailable
		}

		// 2. 按订单明细的规格回补库存，避免取消后库存丢失。
		if err := tx.Where("summary_identity = ?", summary.Identity).Find(&details).Error; err != nil {
			return err
		}
		for _, d := range details {
			if d.Number > 0 {
				if err := tx.Table("mall_product_spec").Where("id = ?", d.SpecID).
					UpdateColumn("stock", gorm.Expr("stock + ?", d.Number)).Error; err != nil {
					return err
				}
			}
		}

		// 3. 退回已使用的优惠券，使其重新可用。
		if summary.CouponIdentity != "" {
			if err := tx.Model(&models.OrderCoupon{}).Where("identity = ?", summary.CouponIdentity).
				Update("status", 2).Error; err != nil {
				return err
			}
		}
		return nil
	})
	if err != nil {
		printer.Error(err.Error())
		if errors.Is(err, errcode.ErrUnavailable) {
			return nil, errcode.ErrUnavailable
		}
		return nil, errcode.ErrDB
	}

	return &pb.OrderStatusReply{
		Code:     0,
		Identity: summary.Identity,
		Message:  "OK",
		Timeseq:  time.Now().UnixNano(),
	}, nil

}