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

@@ -255,11 +255,12 @@ 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 {
+	return r.db.Transaction(func(tx *gorm.DB) 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
+		err := tx.Where("comment_id = ? AND user_id = ?", commentID, userID).First(&existing).Error
 		if err == nil {
 			// 已经点赞
 			return nil
@@ -273,28 +274,30 @@ func (r *CommentRepository) Like(commentID, userID string) error {
 			CommentID: commentID,
 			UserID:    userID,
 		}
-	err = r.db.Create(like).Error
-	if err != nil {
+		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).
+		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{})
+	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 r.db.Model(&model.Comment{}).Where("id = ?", commentID).
+			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
+	if len(ids) == 0 {
+		return nil, nil
+	}
 
-	for _, id := range ids {
-		if err := r.Delete(id); err != nil {
-			failedIDs = append(failedIDs, id)
+	// 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 failedIDs, nil
+		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）

internal/repository/group_repo.go

@@ -4,6 +4,7 @@ import (
 	"carrot_bbs/internal/model"
 	"carrot_bbs/internal/pkg/cursor"
 	"context"
+	"errors"
 
 	"gorm.io/gorm"
 )
@@ -188,6 +189,36 @@ func (r *groupRepository) IsMember(groupID string, userID string) (bool, error)
 	return count > 0, err
 }
 
+// GetExistingMembers 批量检查用户是否是群成员（解决 N+1 问题）
+// 返回 map[userID]bool
+func (r *groupRepository) GetExistingMembers(groupID string, userIDs []string) (map[string]bool, error) {
+	result := make(map[string]bool)
+	if len(userIDs) == 0 || groupID == "" {
+		return result, nil
+	}
+
+	// 初始化所有用户为 false
+	for _, id := range userIDs {
+		result[id] = false
+	}
+
+	// 一次性查询所有群成员记录
+	var existingIDs []string
+	err := r.db.Model(&model.GroupMember{}).
+		Where("group_id = ? AND user_id IN ?", groupID, userIDs).
+		Pluck("user_id", &existingIDs).Error
+	if err != nil {
+		return nil, err
+	}
+
+	// 更新已存在的成员
+	for _, id := range existingIDs {
+		result[id] = true
+	}
+
+	return result, nil
+}
+
 // GetUserGroups 获取用户加入的群组列表
 func (r *groupRepository) GetUserGroups(userID string, page, pageSize int) ([]model.Group, int64, error) {
 	var groups []model.Group
@@ -318,7 +349,7 @@ func (r *groupRepository) GetLatestAnnouncement(groupID string) (*model.GroupAnn
 		Order("is_pinned DESC, created_at DESC").
 		First(&announcement).Error
 	if err != nil {
-		if err == gorm.ErrRecordNotFound {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
 			return nil, nil
 		}
 		return nil, err

internal/repository/login_log_repo.go

@@ -107,7 +107,7 @@ func (r *LoginLogRepository) DeleteOldLogs(ctx context.Context, beforeDate strin
 	return r.db.WithContext(ctx).Where("created_at < ?", beforeDate).Delete(&model.LoginLog{}).Error
 }
 
-// GetStatistics 获取登录日志统计
+// GetStatistics 获取登录日志统计（使用单次 GROUP BY 查询，避免多次 COUNT）
 func (r *LoginLogRepository) GetStatistics(ctx context.Context, startTime, endTime string) (*LoginLogStatistics, error) {
 	stats := &LoginLogStatistics{}
 
@@ -119,20 +119,37 @@ func (r *LoginLogRepository) GetStatistics(ctx context.Context, startTime, endTi
 		query = query.Where("created_at <= ?", endTime)
 	}
 
-	if err := query.Count(&stats.TotalCount).Error; err != nil {
+	// 使用单次 GROUP BY 查询获取 result 计数
+	type resultCount struct {
+		Result string
+		Count  int64
+	}
+	var results []resultCount
+	err := query.Select("result, count(*) as count").Group("result").Scan(&results).Error
+	if err != nil {
 		return nil, err
 	}
 
-	if err := query.Where("result = ?", string(model.LoginResultSuccess)).Count(&stats.SuccessCount).Error; err != nil {
-		return nil, err
+	// 汇总结果
+	for _, r := range results {
+		stats.TotalCount += r.Count
+		if r.Result == string(model.LoginResultSuccess) {
+			stats.SuccessCount = r.Count
+		} else if r.Result == string(model.LoginResultFail) {
+			stats.FailCount = r.Count
+		}
 	}
 
-	if err := query.Where("result = ?", string(model.LoginResultFail)).Count(&stats.FailCount).Error; err != nil {
-		return nil, err
+	// 单独查询登录次数
+	if startTime != "" || endTime != "" {
+		loginQuery := r.db.WithContext(ctx).Model(&model.LoginLog{})
+		if startTime != "" {
+			loginQuery = loginQuery.Where("created_at >= ?", startTime)
 		}
-
-	if err := query.Where("event = ?", string(model.LoginEventLogin)).Count(&stats.LoginCount).Error; err != nil {
-		return nil, err
+		if endTime != "" {
+			loginQuery = loginQuery.Where("created_at <= ?", endTime)
+		}
+		loginQuery.Where("event = ?", string(model.LoginEventLogin)).Count(&stats.LoginCount)
 	}
 
 	return stats, nil

internal/repository/message_repo.go

@@ -4,6 +4,7 @@ import (
 	"carrot_bbs/internal/model"
 	"carrot_bbs/internal/pkg/cursor"
 	"context"
+	"errors"
 	"fmt"
 	"strconv"
 	"strings"
@@ -188,7 +189,7 @@ func (r *MessageRepository) GetParticipant(conversationID string, userID string)
 	err := r.db.Where("conversation_id = ? AND user_id = ?", conversationID, userID).First(&participant).Error
 	if err != nil {
 		// 如果找不到参与者，尝试添加（修复没有参与者记录的问题）
-		if err == gorm.ErrRecordNotFound {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
 			// 检查会话是否存在
 			var conv model.Conversation
 			if err := r.db.Where("id = ?", conversationID).First(&conv).Error; err == nil {
@@ -513,7 +514,7 @@ func (r *MessageRepository) DeleteConversationByGroupID(groupID string) error {
 	conv, err := r.GetConversationByGroupID(groupID)
 	if err != nil {
 		// 如果会话不存在，直接返回
-		if err == gorm.ErrRecordNotFound {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
 			return nil
 		}
 		return err

internal/repository/operation_log_repo.go

@@ -89,7 +89,7 @@ func (r *OperationLogRepository) DeleteOldLogs(ctx context.Context, beforeDate s
 	return r.db.WithContext(ctx).Where("created_at < ?", beforeDate).Delete(&model.OperationLog{}).Error
 }
 
-// GetStatistics 获取操作日志统计
+// GetStatistics 获取操作日志统计（使用单次 GROUP BY 查询，避免多次 COUNT)
 func (r *OperationLogRepository) GetStatistics(ctx context.Context, startTime, endTime string) (*OperationLogStatistics, error) {
 	stats := &OperationLogStatistics{}
 
@@ -101,16 +101,25 @@ func (r *OperationLogRepository) GetStatistics(ctx context.Context, startTime, e
 		query = query.Where("created_at <= ?", endTime)
 	}
 
-	if err := query.Count(&stats.TotalCount).Error; err != nil {
+	// 使用单次 GROUP BY 查询获取各状态计数
+	type statusCount struct {
+		Status string
+		Count  int64
+	}
+	var results []statusCount
+	err := query.Select("status, count(*) as count").Group("status").Scan(&results).Error
+	if err != nil {
 		return nil, err
 	}
 
-	if err := query.Where("status = ?", "success").Count(&stats.SuccessCount).Error; err != nil {
-		return nil, err
+	// 汇总结果
+	for _, r := range results {
+		stats.TotalCount += r.Count
+		if r.Status == "success" {
+			stats.SuccessCount = r.Count
+		} else if r.Status == "fail" {
+			stats.FailCount = r.Count
 		}
-
-	if err := query.Where("status = ?", "fail").Count(&stats.FailCount).Error; err != nil {
-		return nil, err
 	}
 
 	return stats, nil

internal/repository/post_repo.go

@@ -802,30 +802,101 @@ func (r *PostRepository) GetByIDForAdmin(id string) (*model.Post, error) {
 	return &post, nil
 }
 
-// BatchDelete 批量删除帖子
+// BatchDelete 批量删除帖子（使用单次事务批量删除，避免 N+1 问题）
 func (r *PostRepository) 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
+	err := r.db.Transaction(func(tx *gorm.DB) error {
+		// 批量删除帖子图片
+		if err := tx.Where("post_id IN ?", ids).Delete(&model.PostImage{}).Error; err != nil {
+			return err
+		}
+
+		// 批量删除帖子点赞记录
+		if err := tx.Where("post_id IN ?", ids).Delete(&model.PostLike{}).Error; err != nil {
+			return err
+		}
+
+		// 批量删除帖子收藏记录
+		if err := tx.Where("post_id IN ?", ids).Delete(&model.Favorite{}).Error; err != nil {
+			return err
+		}
+
+		// 批量删除评论点赞记录（子查询获取所有评论ID）
+		if err := tx.Where("comment_id IN (SELECT id FROM comments WHERE post_id IN ?)", ids).Delete(&model.CommentLike{}).Error; err != nil {
+			return err
+		}
+
+		// 批量删除帖子评论
+		if err := tx.Where("post_id IN ?", ids).Delete(&model.Comment{}).Error; err != nil {
+			return err
+		}
+
+		// 批量删除投票选项
+		if err := tx.Where("post_id IN ?", ids).Delete(&model.VoteOption{}).Error; err != nil {
+			return err
+		}
+
+		// 批量删除用户投票记录
+		if err := tx.Where("post_id IN ?", ids).Delete(&model.UserVote{}).Error; err != nil {
+			return err
+		}
+
+		// 最后批量删除帖子本身（软删除）
+		return tx.Where("id IN ?", ids).Delete(&model.Post{}).Error
+	})
+
+	if err != nil {
+		return ids, err
+	}
+	return nil, nil
 }
 
-// BatchUpdateStatus 批量更新帖子审核状态
+// BatchUpdateStatus 批量更新帖子审核状态（使用单条 SQL 批量更新，避免 N+1 问题）
 func (r *PostRepository) BatchUpdateStatus(ids []string, status model.PostStatus, reviewedBy string) ([]string, error) {
-	var failedIDs []string
+	if len(ids) == 0 {
+		return nil, nil
+	}
 
+	// 使用单条 SQL 批量更新
+	result := r.db.Model(&model.Post{}).
+		Where("id IN ?", ids).
+		Updates(map[string]any{
+			"status":       status,
+			"reviewed_at":  gorm.Expr("CURRENT_TIMESTAMP"),
+			"reviewed_by":  reviewedBy,
+			"reject_reason": "",
+			"updated_at":   gorm.Expr("updated_at"),
+		})
+
+	if result.Error != nil {
+		return ids, result.Error
+	}
+
+	// 返回实际更新的帖子数量
+	if result.RowsAffected < int64(len(ids)) {
+		// 部分帖子可能不存在，查询实际更新的 ID
+		var updatedIDs []string
+		r.db.Model(&model.Post{}).Where("id IN ?", ids).Pluck("id", &updatedIDs)
+
+		// 找出未更新的 ID
+		updatedMap := make(map[string]bool, len(updatedIDs))
+		for _, id := range updatedIDs {
+			updatedMap[id] = true
+		}
+
+		var failedIDs []string
 		for _, id := range ids {
-		if err := r.UpdateModerationStatus(id, status, "", reviewedBy); err != nil {
+			if !updatedMap[id] {
 				failedIDs = append(failedIDs, id)
 			}
 		}
-
 		return failedIDs, nil
+	}
+
+	return nil, nil
 }
 
 // UpdatePinStatus 更新帖子置顶状态

internal/repository/sticker_repo.go

@@ -2,6 +2,7 @@ package repository
 
 import (
 	"carrot_bbs/internal/model"
+	"strings"
 
 	"gorm.io/gorm"
 )
@@ -88,18 +89,31 @@ func (r *stickerRepository) UpdateSortOrder(id string, sortOrder int) error {
 		Update("sort_order", sortOrder).Error
 }
 
-// BatchUpdateSortOrder 批量更新排序
+// BatchUpdateSortOrder 批量更新排序（使用 CASE WHEN 批量更新，避免 N+1 问题）
 func (r *stickerRepository) BatchUpdateSortOrder(userID string, orders map[string]int) error {
-	return r.db.Transaction(func(tx *gorm.DB) error {
-		for id, sortOrder := range orders {
-			if err := tx.Model(&model.UserSticker{}).
-				Where("id = ? AND user_id = ?", id, userID).
-				Update("sort_order", sortOrder).Error; err != nil {
-				return err
-			}
-		}
+	if len(orders) == 0 {
 		return nil
-	})
+	}
+
+	// 构建 CASE WHEN 批量更新 SQL
+	var cases []string
+	var args []any
+
+	for id, sortOrder := range orders {
+		cases = append(cases, "WHEN id = ? THEN ?")
+		args = append(args, id, sortOrder)
+	}
+
+	ids := make([]string, 0, len(orders))
+	for id := range orders {
+		ids = append(ids, id)
+	}
+
+	sql := `UPDATE user_stickers SET sort_order = CASE ` + 
+		strings.Join(cases, " ") + ` END WHERE id IN ? AND user_id = ?`
+	args = append(args, ids, userID)
+
+	return r.db.Exec(sql, args...).Error
 }
 
 // CountByUserID 获取用户表情数量

internal/repository/user_repo.go

@@ -140,6 +140,36 @@ func (r *UserRepository) IsFollowing(followerID, followingID string) (bool, erro
 	return count > 0, nil
 }
 
+// IsFollowingBatch 批量检查当前用户是否关注了目标用户（解决 N+1 问题）
+// 返回 map[targetUserID]bool
+func (r *UserRepository) IsFollowingBatch(followerID string, targetUserIDs []string) (map[string]bool, error) {
+	result := make(map[string]bool)
+	if len(targetUserIDs) == 0 || followerID == "" {
+		return result, nil
+	}
+
+	// 初始化所有目标用户为 false
+	for _, id := range targetUserIDs {
+		result[id] = false
+	}
+
+	// 一次性查询所有关注记录
+	var followingIDs []string
+	err := r.db.Model(&model.Follow{}).
+		Where("follower_id = ? AND following_id IN ?", followerID, targetUserIDs).
+		Pluck("following_id", &followingIDs).Error
+	if err != nil {
+		return nil, err
+	}
+
+	// 更新已关注的用户
+	for _, id := range followingIDs {
+		result[id] = true
+	}
+
+	return result, nil
+}
+
 // IncrementFollowersCount 增加用户粉丝数
 func (r *UserRepository) IncrementFollowersCount(userID string) error {
 	return r.db.Model(&model.User{}).Where("id = ?", userID).
@@ -243,6 +273,36 @@ func (r *UserRepository) IsBlocked(blockerID, blockedID string) (bool, error) {
 	return count > 0, nil
 }
 
+// IsBlockedBatch 批量检查拉黑关系（解决 N+1 问题）
+// 返回 map[blockedUserID]bool
+func (r *UserRepository) IsBlockedBatch(blockerID string, blockedIDs []string) (map[string]bool, error) {
+	result := make(map[string]bool)
+	if len(blockedIDs) == 0 || blockerID == "" {
+		return result, nil
+	}
+
+	// 初始化所有目标用户为 false
+	for _, id := range blockedIDs {
+		result[id] = false
+	}
+
+	// 一次性查询所有拉黑记录
+	var blockedUserIDs []string
+	err := r.db.Model(&model.UserBlock{}).
+		Where("blocker_id = ? AND blocked_id IN ?", blockerID, blockedIDs).
+		Pluck("blocked_id", &blockedUserIDs).Error
+	if err != nil {
+		return nil, err
+	}
+
+	// 更新已拉黑的用户
+	for _, id := range blockedUserIDs {
+		result[id] = true
+	}
+
+	return result, nil
+}
+
 // IsBlockedEitherDirection 检查是否任一方向存在拉黑
 func (r *UserRepository) IsBlockedEitherDirection(userA, userB string) (bool, error) {
 	var count int64

internal/repository/vote_repo.go

@@ -17,21 +17,24 @@ func NewVoteRepository(db *gorm.DB) *VoteRepository {
 	return &VoteRepository{db: db}
 }
 
-// CreateOptions 批量创建投票选项
+// CreateOptions 批量创建投票选项（使用批量插入，避免 N+1 问题）
 func (r *VoteRepository) CreateOptions(postID string, options []string) error {
-	return r.db.Transaction(func(tx *gorm.DB) error {
+	if len(options) == 0 {
+		return nil
+	}
+
+	// 构建批量插入的选项切片
+	voteOptions := make([]model.VoteOption, len(options))
 	for i, content := range options {
-			option := &model.VoteOption{
+		voteOptions[i] = model.VoteOption{
 			PostID:    postID,
 			Content:   content,
 			SortOrder: i,
 		}
-			if err := tx.Create(option).Error; err != nil {
-				return err
 	}
-		}
-		return nil
-	})
+
+	// 使用 GORM 的 Create 方法批量插入
+	return r.db.CreateInBatches(voteOptions, 100).Error
 }
 
 // GetOptionsByPostID 获取帖子的所有投票选项
@@ -58,7 +61,7 @@ func (r *VoteRepository) Vote(postID, userID, optionID string) error {
 		// 验证选项是否属于该帖子
 		var option model.VoteOption
 		if err := tx.Where("id = ? AND post_id = ?", optionID, postID).First(&option).Error; err != nil {
-			if err == gorm.ErrRecordNotFound {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
 			return errors.New("invalid option")
 		}
 			return err
@@ -86,7 +89,7 @@ func (r *VoteRepository) Unvote(postID, userID string) error {
 		var userVote model.UserVote
 		err := tx.Where("post_id = ? AND user_id = ?", postID, userID).First(&userVote).Error
 		if err != nil {
-			if err == gorm.ErrRecordNotFound {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
 			return nil // 没有投票记录，直接返回
 		}
 			return err
@@ -113,7 +116,7 @@ func (r *VoteRepository) GetUserVote(postID, userID string) (*model.UserVote, er
 	var userVote model.UserVote
 	err := r.db.Where("post_id = ? AND user_id = ?", postID, userID).First(&userVote).Error
 	if err != nil {
-		if err == gorm.ErrRecordNotFound {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
 			return nil, nil
 		}
 		return nil, err