修复(#75): 适配促销数量与永久订阅判定

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

internal/logic/public/subscribe/promo.go

@@ -15,6 +15,7 @@ import (
 	"github.com/perfect-panel/server/pkg/xerr"
 	"github.com/pkg/errors"
 	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
 )
 
 const (
@@ -171,11 +172,7 @@ func (e *promoEligibilityEvaluator) lastSubscribeExpireAt() (time.Time, error) {
 		return *e.lastExpire, nil
 	}
 	var item user.Subscribe
-	err := e.db.WithContext(e.ctx).
-		Model(&user.Subscribe{}).
-		Where("user_id = ?", e.userInfo.Id).
-		Where("expire_time != ?", time.UnixMilli(0)).
-		Order("expire_time DESC").
+	err := e.lastSubscribeExpireQuery().
 		Limit(1).
 		Take(&item).Error
 	if err != nil {
@@ -190,6 +187,18 @@ func (e *promoEligibilityEvaluator) lastSubscribeExpireAt() (time.Time, error) {
 	return item.ExpireTime, nil
 }
 
+func (e *promoEligibilityEvaluator) lastSubscribeExpireQuery() *gorm.DB {
+	return e.db.WithContext(e.ctx).
+		Model(&user.Subscribe{}).
+		Where("user_id = ?", e.userInfo.Id).
+		Order(clause.OrderBy{
+			Expression: clause.Expr{
+				SQL:  "CASE WHEN expire_time = ? THEN 0 ELSE 1 END, expire_time DESC",
+				Vars: []interface{}{time.UnixMilli(0)},
+			},
+		})
+}
+
 func (c subscribePromoCandidate) expiresAt() time.Time {
 	if c.EndTime == nil {
 		return time.Time{}