feat:添加热榜功能并添加了增加热度的方法。

backend/internal/feed/repo.go

@@ -68,3 +68,36 @@ func (repo *FeedRepository) ListByFollowing(ctx context.Context, limit int, view
 	}
 	return videos, nil
 }
+
+func (repo *FeedRepository) ListByPopularity(ctx context.Context, limit int, popularityBefore int64, timeBefore time.Time, idBefore uint) ([]*video.Video, error) {
+	var videos []*video.Video
+	query := repo.db.WithContext(ctx).Model(&video.Video{}).
+		Order("popularity DESC, create_time DESC, id DESC")
+
+	// 只有当游标完整提供时才加过滤（popularity 允许为 0）
+	if !timeBefore.IsZero() && idBefore > 0 {
+		query = query.Where(
+			"(popularity < ?) OR (popularity = ? AND create_time < ?) OR (popularity = ? AND create_time = ? AND id < ?)",
+			popularityBefore,
+			popularityBefore, timeBefore,
+			popularityBefore, timeBefore, idBefore,
+		)
+	}
+
+	if err := query.Limit(limit).Find(&videos).Error; err != nil {
+		return nil, err
+	}
+	return videos, nil
+}
+
+func (repo *FeedRepository) GetByIDs(ctx context.Context, ids []uint) ([]*video.Video, error) {
+	var videos []*video.Video
+	if len(ids) == 0 {
+		return videos, nil
+	}
+	if err := repo.db.WithContext(ctx).Model(&video.Video{}).
+		Where("id IN ?", ids).Find(&videos).Error; err != nil {
+		return nil, err
+	}
+	return videos, nil
+}