修复(#84): 补齐促销管理API实现文件

Co-authored-by: multica-agent <github@multica.ai>

internal/logic/admin/promo/getPromoRuleDetailLogic.go

@@ -0,0 +1,39 @@
+package promo
+
+import (
+	"context"
+
+	promoModel "github.com/perfect-panel/server/internal/model/promo"
+	"github.com/perfect-panel/server/internal/svc"
+	"github.com/perfect-panel/server/internal/types"
+	"github.com/perfect-panel/server/pkg/logger"
+	"github.com/perfect-panel/server/pkg/xerr"
+)
+
+type GetPromoRuleDetailLogic struct {
+	logger.Logger
+	ctx    context.Context
+	svcCtx *svc.ServiceContext
+}
+
+// Get promo rule detail
+func NewGetPromoRuleDetailLogic(ctx context.Context, svcCtx *svc.ServiceContext) *GetPromoRuleDetailLogic {
+	return &GetPromoRuleDetailLogic{
+		Logger: logger.WithContext(ctx),
+		ctx:    ctx,
+		svcCtx: svcCtx,
+	}
+}
+
+func (l *GetPromoRuleDetailLogic) GetPromoRuleDetail(req *types.GetPromoRuleDetailRequest) (*types.PromoRule, error) {
+	data, err := l.svcCtx.PromoModel.FindRule(l.ctx, req.Id)
+	if err != nil {
+		if promoModel.IsNotFound(err) {
+			return nil, xerr.NewErrCodeMsg(xerr.InvalidParams, "promo rule not found")
+		}
+		l.Errorw("[GetPromoRuleDetail] Database Error", logger.Field("error", err.Error()))
+		return nil, wrapQueryError("get promo rule detail failed", err)
+	}
+	resp := toRuleResponse(data)
+	return &resp, nil
+}