feat: 实现评论系统（后端 + 前端）

- 新增 Comment/CommentMention 模型，Post 新增 CommentsCount 冗余计数器 - 新增 CommentRepo（CRUD + @搜索 LV3+ + 回复统计 + 文章作者查询） - 新增 CommentService（发表/回复/删除/@解析/通知 NotifyComment/NotifyCommentReply） - 新增 CommentController（6 个 API 端点），commentUseCase ISP 接口 - 新增评论路由（公开读取 + 需登录写入），依赖注入，错误哨兵，数据库迁移 - 前端评论区 HTML/CSS/JS：分页加载、回复折叠展开、内联回复表单、@提及自动补全
2026-06-01 13:24:16 +08:00
parent b44d7ca5c3
commit b7acc91f8c
15 changed files with 1416 additions and 7 deletions
--- a/internal/repository/comment_repo.go
+++ b/internal/repository/comment_repo.go
@ -0,0 +1,250 @@
+package repository
+
+import (
+	"metazone.cc/metalab/internal/model"
+	"strconv"
+
+	"gorm.io/gorm"
+)
+
+// CommentRepo 评论数据访问
+type CommentRepo struct {
+	db *gorm.DB
+}
+
+// NewCommentRepo 构造函数
+func NewCommentRepo(db *gorm.DB) *CommentRepo {
+	return &CommentRepo{db: db}
+}
+
+// Create 创建评论
+func (r *CommentRepo) Create(comment *model.Comment) error {
+	return r.db.Create(comment).Error
+}
+
+// FindByID 按 ID 查找评论（含作者信息）
+func (r *CommentRepo) FindByID(id uint) (*model.Comment, error) {
+	var c model.Comment
+	err := r.db.Table("comments").
+		Select("comments.*, users.username as author_name, users.avatar as author_avatar").
+		Joins("LEFT JOIN users ON users.uid = comments.user_id").
+		Where("comments.id = ?", id).
+		First(&c).Error
+	if err != nil {
+		return nil, err
+	}
+	return &c, nil
+}
+
+// FindRootComments 分页查询文章的顶级评论（parent_id IS NULL，未删除）
+func (r *CommentRepo) FindRootComments(postID uint, offset, limit int) ([]model.Comment, int64, error) {
+	var total int64
+	base := r.db.Table("comments").
+		Where("post_id = ? AND parent_id IS NULL AND is_deleted = false", postID)
+
+	if err := base.Count(&total).Error; err != nil {
+		return nil, 0, err
+	}
+
+	var list []model.Comment
+	err := base.
+		Select("comments.*, users.username as author_name, users.avatar as author_avatar").
+		Joins("LEFT JOIN users ON users.uid = comments.user_id").
+		Order("comments.created_at DESC").
+		Offset(offset).Limit(limit).
+		Find(&list).Error
+	if err != nil {
+		return nil, 0, err
+	}
+
+	// 为每条顶级评论填充回复数
+	if len(list) > 0 {
+		ids := make([]uint, len(list))
+		for i, c := range list {
+			ids[i] = c.ID
+		}
+		countMap := r.batchCountReplies(ids)
+		for i := range list {
+			list[i].RepliesCount = countMap[list[i].ID]
+		}
+	}
+
+	return list, total, nil
+}
+
+// FindReplies 查询某条顶级评论的所有回复（不分页，全量返回，未删除）
+func (r *CommentRepo) FindReplies(rootID uint) ([]model.Comment, error) {
+	var list []model.Comment
+	err := r.db.Table("comments").
+		Select("comments.*, users.username as author_name, users.avatar as author_avatar").
+		Joins("LEFT JOIN users ON users.uid = comments.user_id").
+		Where("comments.root_id = ? AND comments.parent_id IS NOT NULL AND comments.is_deleted = false", rootID).
+		Order("comments.created_at ASC").
+		Find(&list).Error
+	if err != nil {
+		return nil, err
+	}
+
+	// 填充 reply_to_name
+	r.fillReplyToNames(list)
+
+	return list, nil
+}
+
+// fillReplyToNames 通过 JOIN users 获取被回复者当前显示名
+func (r *CommentRepo) fillReplyToNames(list []model.Comment) {
+	if len(list) == 0 {
+		return
+	}
+	type nameRow struct {
+		UID      string
+		Username string
+	}
+	var rows []nameRow
+	r.db.Table("users").
+		Select("uid, username").
+		Where("uid IN (SELECT reply_to_uid FROM comments WHERE root_id IN (?) AND parent_id IS NOT NULL)", r.rootIDsFromList(list)).
+		Find(&rows)
+
+	m := make(map[string]string)
+	for _, row := range rows {
+		m[row.UID] = row.Username
+	}
+	for i := range list {
+		if list[i].ReplyToUID != "" {
+			list[i].ReplyToName = m[list[i].ReplyToUID]
+		}
+	}
+}
+
+func (r *CommentRepo) rootIDsFromList(list []model.Comment) []uint {
+	ids := make([]uint, len(list))
+	for i, c := range list {
+		ids[i] = c.RootID
+	}
+	return ids
+}
+
+// batchCountReplies 批量统计回复数
+func (r *CommentRepo) batchCountReplies(rootIDs []uint) map[uint]int {
+	type countRow struct {
+		RootID uint
+		Count  int
+	}
+	var rows []countRow
+	r.db.Table("comments").
+		Select("root_id, COUNT(*) as count").
+		Where("root_id IN ? AND parent_id IS NOT NULL AND is_deleted = false", rootIDs).
+		Group("root_id").
+		Find(&rows)
+
+	m := make(map[uint]int)
+	for _, row := range rows {
+		m[row.RootID] = row.Count
+	}
+	return m
+}
+
+// SoftDelete 软删除评论（设置 is_deleted=true）
+func (r *CommentRepo) SoftDelete(id uint) error {
+	return r.db.Model(&model.Comment{}).Where("id = ?", id).Update("is_deleted", true).Error
+}
+
+// IncrCommentsCount 文章评论数+1
+func (r *CommentRepo) IncrCommentsCount(postID uint) error {
+	return r.db.Model(&model.Post{}).Where("id = ?", postID).
+		UpdateColumn("comments_count", gorm.Expr("comments_count + 1")).Error
+}
+
+// DecrCommentsCount 文章评论数-1
+func (r *CommentRepo) DecrCommentsCount(postID uint) error {
+	return r.db.Model(&model.Post{}).Where("id = ?", postID).
+		UpdateColumn("comments_count", gorm.Expr("GREATEST(comments_count - 1, 0)")).Error
+}
+
+// CountRepliesByRootByStatus 统计某条顶级评论的回复数（可选是否统计已删除）
+func (r *CommentRepo) CountRepliesByRoot(rootID uint, includeDeleted bool) (int, error) {
+	var count int64
+	q := r.db.Model(&model.Comment{}).Where("root_id = ? AND parent_id IS NOT NULL", rootID)
+	if !includeDeleted {
+		q = q.Where("is_deleted = false")
+	}
+	err := q.Count(&count).Error
+	return int(count), err
+}
+
+// CreateMention 创建@提及记录
+func (r *CommentRepo) CreateMention(mention *model.CommentMention) error {
+	return r.db.Create(mention).Error
+}
+
+// FindMentionsByComment 查询某条评论的@提及列表
+func (r *CommentRepo) FindMentionsByComment(commentID uint) ([]model.CommentMention, error) {
+	var list []model.CommentMention
+	err := r.db.Where("comment_id = ?", commentID).Find(&list).Error
+	return list, err
+}
+
+// SearchUsersByLevel 搜索 LV3+ 用户（用于@艾特）
+func (r *CommentRepo) SearchUsersByLevel(keyword string, minLevel int, limit int) ([]struct {
+	UID      string
+	Username string
+}, error) {
+	// LV3 = 1500 exp
+	type result struct {
+		UID      string
+		Username string
+	}
+	var list []result
+
+	// level 是计算字段，用 exp >= thresholds[minLevel] 判断
+	threshold := model.LevelThresholds[minLevel]
+
+	err := r.db.Table("users").
+		Select("uid, username").
+		Where("username LIKE ? AND exp >= ? AND deleted_at IS NULL", "%"+keyword+"%", threshold).
+		Order("exp DESC").
+		Limit(limit).
+		Find(&list).Error
+
+	var res []struct {
+		UID      string
+		Username string
+	}
+	for _, u := range list {
+		res = append(res, struct {
+			UID      string
+			Username string
+		}{UID: u.UID, Username: u.Username})
+	}
+	return res, err
+}
+
+// GetUserUIDByID 通过 uint ID 获取 user 的 UID 字符串
+func (r *CommentRepo) GetUserUIDByID(userID uint) (string, error) {
+	var uid uint
+	err := r.db.Table("users").Select("uid").Where("uid = ?", userID).Scan(&uid).Error
+	if err != nil {
+		return "", err
+	}
+	return strconv.FormatUint(uint64(uid), 10), nil
+}
+
+// FindPostIDByComment 查询评论所属的文章ID
+func (r *CommentRepo) FindPostIDByComment(commentID uint) (uint, error) {
+	var postID uint
+	err := r.db.Table("comments").Select("post_id").Where("id = ?", commentID).Scan(&postID).Error
+	return postID, err
+}
+
+// UpdateRootID 更新评论的 root_id 字段（顶级评论创建后回填）
+func (r *CommentRepo) UpdateRootID(id, rootID uint) error {
+	return r.db.Model(&model.Comment{}).Where("id = ?", id).Update("root_id", rootID).Error
+}
+
+// FindPostAuthorID 查询文章的作者 user_id
+func (r *CommentRepo) FindPostAuthorID(postID uint) (uint, error) {
+	var authorID uint
+	err := r.db.Table("posts").Select("user_id").Where("id = ?", postID).Scan(&authorID).Error
+	return authorID, err
+}