feat(repository): enhance repository methods with batch processing and transaction support

- Updated Like and Unlike methods in CommentRepository to use transactions for data consistency.
- Introduced IsLikedBatch method for batch checking if comments are liked, addressing N+1 query issues.
- Enhanced BatchDelete method in PostRepository to perform batch deletions within a single transaction, improving efficiency.
- Added BatchUpdateStatus method for posts to utilize a single SQL update for status changes, reducing database load.
- Implemented BatchUpdateSortOrder in StickerRepository using CASE WHEN for efficient sorting updates.
- Added IsFollowingBatch and IsBlockedBatch methods in UserRepository for batch checking follow and block relationships, optimizing performance.

internal/repository/comment_repo.go

@@ -255,46 +255,49 @@ func (r *CommentRepository) GetReplies(parentID string) ([]*model.Comment, error
 	return comments, err
 }
 
-// Like 点赞评论
+// Like 点赞评论（使用事务保证数据一致性）
 func (r *CommentRepository) Like(commentID, userID string) error {
-	// 检查是否已经点赞
-	var existing model.CommentLike
-	err := r.db.Where("comment_id = ? AND user_id = ?", commentID, userID).First(&existing).Error
-	if err == nil {
-		// 已经点赞
-		return nil
-	}
-	if err != gorm.ErrRecordNotFound {
-		return err
-	}
+	return r.db.Transaction(func(tx *gorm.DB) error {
+		// 检查是否已经点赞
+		var existing model.CommentLike
+		err := tx.Where("comment_id = ? AND user_id = ?", commentID, userID).First(&existing).Error
+		if err == nil {
+			// 已经点赞
+			return nil
+		}
+		if err != gorm.ErrRecordNotFound {
+			return err
+		}
 
-	// 创建点赞记录
-	like := &model.CommentLike{
-		CommentID: commentID,
-		UserID:    userID,
-	}
-	err = r.db.Create(like).Error
-	if err != nil {
-		return err
-	}
+		// 创建点赞记录
+		like := &model.CommentLike{
+			CommentID: commentID,
+			UserID:    userID,
+		}
+		if err := tx.Create(like).Error; err != nil {
+			return err
+		}
 
-	// 增加评论点赞数
-	return r.db.Model(&model.Comment{}).Where("id = ?", commentID).
-		UpdateColumn("likes_count", gorm.Expr("likes_count + 1")).Error
+		// 增加评论点赞数
+		return tx.Model(&model.Comment{}).Where("id = ?", commentID).
+			UpdateColumn("likes_count", gorm.Expr("likes_count + 1")).Error
+	})
 }
 
-// Unlike 取消点赞评论
+// Unlike 取消点赞评论（使用事务保证数据一致性）
 func (r *CommentRepository) Unlike(commentID, userID string) error {
-	result := r.db.Where("comment_id = ? AND user_id = ?", commentID, userID).Delete(&model.CommentLike{})
-	if result.Error != nil {
-		return result.Error
-	}
-	if result.RowsAffected > 0 {
-		// 减少评论点赞数
-		return r.db.Model(&model.Comment{}).Where("id = ?", commentID).
-			UpdateColumn("likes_count", gorm.Expr("likes_count - 1")).Error
-	}
-	return nil
+	return r.db.Transaction(func(tx *gorm.DB) error {
+		result := tx.Where("comment_id = ? AND user_id = ?", commentID, userID).Delete(&model.CommentLike{})
+		if result.Error != nil {
+			return result.Error
+		}
+		if result.RowsAffected > 0 {
+			// 减少评论点赞数
+			return tx.Model(&model.Comment{}).Where("id = ?", commentID).
+				UpdateColumn("likes_count", gorm.Expr("likes_count - 1")).Error
+		}
+		return nil
+	})
 }
 
 // IsLiked 检查是否已点赞
@@ -304,6 +307,33 @@ func (r *CommentRepository) IsLiked(commentID, userID string) bool {
 	return count > 0
 }
 
+// IsLikedBatch 批量检查是否点赞（解决 N+1 问题）
+// 返回 map[commentID]bool
+func (r *CommentRepository) IsLikedBatch(commentIDs []string, userID string) map[string]bool {
+	result := make(map[string]bool)
+	if len(commentIDs) == 0 || userID == "" {
+		return result
+	}
+
+	// 初始化所有 commentID 为 false
+	for _, commentID := range commentIDs {
+		result[commentID] = false
+	}
+
+	// 一次性查询所有点赞记录
+	var likedCommentIDs []string
+	r.db.Model(&model.CommentLike{}).
+		Where("comment_id IN ? AND user_id = ?", commentIDs, userID).
+		Pluck("comment_id", &likedCommentIDs)
+
+	// 更新已点赞的评论
+	for _, commentID := range likedCommentIDs {
+		result[commentID] = true
+	}
+
+	return result
+}
+
 // AdminCommentListFilter 管理端评论列表筛选条件
 type AdminCommentListFilter struct {
 	Keyword   string
@@ -367,17 +397,58 @@ func (r *CommentRepository) GetAdminCommentByID(id string) (*model.Comment, erro
 	return &comment, nil
 }
 
-// BatchDelete 批量删除评论
+// BatchDelete 批量删除评论（使用单次事务批量删除，避免 N+1 问题）
 func (r *CommentRepository) BatchDelete(ids []string) ([]string, error) {
-	var failedIDs []string
-
-	for _, id := range ids {
-		if err := r.Delete(id); err != nil {
-			failedIDs = append(failedIDs, id)
-		}
+	if len(ids) == 0 {
+		return nil, nil
 	}
 
-	return failedIDs, nil
+	// 先查询所有评论获取 post_id 和状态信息
+	type commentInfo struct {
+		ID     string
+		PostID string
+		Status model.CommentStatus
+	}
+	var comments []commentInfo
+	if err := r.db.Model(&model.Comment{}).Where("id IN ?", ids).Scan(&comments).Error; err != nil {
+		return ids, err
+	}
+
+	err := r.db.Transaction(func(tx *gorm.DB) error {
+		// 批量删除评论点赞记录
+		if err := tx.Where("comment_id IN ?", ids).Delete(&model.CommentLike{}).Error; err != nil {
+			return err
+		}
+
+		// 批量删除评论（软删除）
+		if err := tx.Where("id IN ?", ids).Delete(&model.Comment{}).Error; err != nil {
+			return err
+		}
+
+		// 更新帖子的评论数（仅统计已发布评论）
+		postCountMap := make(map[string]int)
+		for _, c := range comments {
+			if c.Status == model.CommentStatusPublished {
+				postCountMap[c.PostID]++
+			}
+		}
+		for postID, count := range postCountMap {
+			if err := tx.Model(&model.Post{}).Where("id = ?", postID).
+				UpdateColumns(map[string]any{
+					"comments_count": gorm.Expr("comments_count - ?", count),
+					"updated_at":     gorm.Expr("updated_at"),
+				}).Error; err != nil {
+				return err
+			}
+		}
+
+		return nil
+	})
+
+	if err != nil {
+		return ids, err
+	}
+	return nil, nil
 }
 
 // GetCommentsByPostIDForAdmin 管理端获取帖子的评论列表（包含所有状态）