backend/internal/service/comment_service.go

package service

import (
	"context"
	"fmt"
	"log"
	"strings"

	apperrors "with_you/internal/errors"
	"with_you/internal/cache"
	"with_you/internal/dto"
	"with_you/internal/model"
	"with_you/internal/pkg/cursor"
	"with_you/internal/pkg/hook"
	"with_you/internal/repository"

	"go.uber.org/zap"
)

type CommentService struct {
	commentRepo          repository.CommentRepository
	postRepo             repository.PostRepository
	systemMessageService SystemMessageService
	cache                cache.Cache
	postAIService        *PostAIService
	logService           *LogService
	hookManager          *hook.Manager
}

func NewCommentService(commentRepo repository.CommentRepository, postRepo repository.PostRepository, systemMessageService SystemMessageService, postAIService *PostAIService, cacheBackend cache.Cache, hookManager *hook.Manager, logService *LogService) *CommentService {
	return &CommentService{
		commentRepo:          commentRepo,
		postRepo:             postRepo,
		systemMessageService: systemMessageService,
		cache:                cacheBackend,
		postAIService:        postAIService,
		logService:           logService,
		hookManager:          hookManager,
	}
}

// Create 创建评论
func (s *CommentService) Create(ctx context.Context, postID, userID, content string, segments model.MessageSegments, parentID *string, images string, imageURLs []string) (*model.Comment, error) {
	if s.postAIService != nil {
		// 采用异步审核，前端先立即返回
	}

	// 获取帖子信息用于发送通知
	post, err := s.postRepo.GetByID(postID)
	if err != nil {
		return nil, err
	}

	comment := &model.Comment{
		PostID:   postID,
		UserID:   userID,
		Content:  content,
		Segments: segments,
		ParentID: parentID,
		Images:   images,
		Status:   model.CommentStatusPending,
	}

	// 如果有父评论，设置根评论ID
	var parentUserID string
	if parentID != nil {
		parent, err := s.commentRepo.GetByID(*parentID)
		if err == nil && parent != nil {
			if parent.RootID != nil {
				comment.RootID = parent.RootID
			} else {
				comment.RootID = parentID
			}
			parentUserID = parent.UserID
		}
	}

	err = s.commentRepo.Create(comment)
	if err != nil {
		return nil, err
	}

	// 记录操作日志
	if s.logService != nil {
		s.logService.OperationLog.RecordOperation(&model.OperationLog{
			UserID:     userID,
			Operation:  string(model.OpCommentCreate),
			Module:     "comment",
			TargetType: "comment",
			TargetID:   comment.ID,
			Status:     "success",
		})
	}

	// 重新查询以获取关联的 User
	comment, err = s.commentRepo.GetByID(comment.ID)
	if err != nil {
		return nil, err
	}

	// 异步处理 @提及通知
	if len(segments) > 0 {
		bgCtx := context.WithoutCancel(ctx)
		go s.processCommentMentionNotifications(bgCtx, userID, postID, post.Title, segments)
	}

	go s.reviewCommentAsync(comment.ID, userID, postID, content, imageURLs, parentID, parentUserID, post.UserID)

	return comment, nil
}

// processCommentMentionNotifications 处理评论中 @提及的通知
func (s *CommentService) processCommentMentionNotifications(ctx context.Context, authorID, postID, postTitle string, segments model.MessageSegments) {
	if s.systemMessageService == nil {
		return
	}

	mentionedUserIDs := dto.ExtractMentionedUsers(segments)
	if len(mentionedUserIDs) == 0 {
		return
	}

	for _, targetUserID := range mentionedUserIDs {
		if targetUserID == authorID {
			continue
		}
		if err := s.systemMessageService.SendMentionNotification(ctx, targetUserID, authorID, postID); err != nil {
			log.Printf("[WARN] Failed to send comment mention notification to user %s: %v", targetUserID, err)
		}
	}
}

func (s *CommentService) reviewCommentAsync(
	commentID, userID, postID, content string,
	imageURLs []string,
	parentID *string,
	parentUserID string,
	postOwnerID string,
) {
	if s.hookManager == nil {
		if err := s.commentRepo.UpdateModerationStatus(commentID, model.CommentStatusPublished, "", "system"); err != nil {
			zap.L().Warn("Failed to publish comment without hook manager",
				zap.Error(err),
			)
			return
		}
		if err := s.applyCommentPublishedStats(commentID); err != nil {
			zap.L().Warn("Failed to apply published stats for comment",
				zap.String("commentID", commentID),
				zap.Error(err),
			)
		}
		s.invalidatePostCaches(postID)
		s.afterCommentPublished(userID, postID, commentID, parentID, parentUserID, postOwnerID)
		return
	}

	var authorID uint
	fmt.Sscanf(userID, "%d", &authorID)

	result := &hook.ModerationResult{}
	s.hookManager.TriggerWithMetadata(context.Background(), hook.HookCommentPreModerate, authorID, &hook.CommentModerateHookData{
		CommentID: commentID,
		PostID:    postID,
		Content:   content,
		Images:    imageURLs,
		AuthorID:  authorID,
		ParentID:  parentID,
	}, map[string]any{
		"result": result,
	})

	s.hookManager.Trigger(context.Background(), hook.HookCommentModerated, authorID, &hook.CommentModeratedHookData{
		CommentID:    commentID,
		PostID:       postID,
		AuthorID:     authorID,
		Approved:     result.Approved,
		RejectReason: result.RejectReason,
		ReviewedBy:   result.ReviewedBy,
	})

	if !result.Approved {
		if result.NeedsReview {
			s.invalidatePostCaches(postID)
			return
		}
		if delErr := s.commentRepo.Delete(commentID); delErr != nil {
			zap.L().Warn("Failed to delete rejected comment",
				zap.String("commentID", commentID),
				zap.Error(delErr),
			)
		}
		s.notifyCommentModerationRejected(userID, result.RejectReason)
		return
	}

	if updateErr := s.commentRepo.UpdateModerationStatus(commentID, model.CommentStatusPublished, "", result.ReviewedBy); updateErr != nil {
		zap.L().Warn("Failed to publish comment",
			zap.String("commentID", commentID),
			zap.Error(updateErr),
		)
		return
	}
	if statsErr := s.applyCommentPublishedStats(commentID); statsErr != nil {
		zap.L().Warn("Failed to apply published stats for comment",
			zap.String("commentID", commentID),
			zap.Error(statsErr),
		)
	}
	s.invalidatePostCaches(postID)
	s.afterCommentPublished(userID, postID, commentID, parentID, parentUserID, postOwnerID)
}

func (s *CommentService) applyCommentPublishedStats(commentID string) error {
	comment, err := s.commentRepo.GetByID(commentID)
	if err != nil {
		return err
	}
	return s.commentRepo.ApplyPublishedStats(comment)
}

func (s *CommentService) invalidatePostCaches(postID string) {
	cache.InvalidatePostDetail(s.cache, postID)
	cache.InvalidatePostList(s.cache)
}

func (s *CommentService) afterCommentPublished(userID, postID, commentID string, parentID *string, parentUserID, postOwnerID string) {
	// 发送系统消息通知
	if s.systemMessageService != nil {
		go func() {
			if parentID != nil && parentUserID != "" {
				// 回复评论，通知被回复的人
				if parentUserID != userID {
					notifyErr := s.systemMessageService.SendReplyNotification(context.Background(), parentUserID, userID, postID, *parentID, commentID)
					if notifyErr != nil {
						zap.L().Error("Error sending reply notification",
							zap.Error(notifyErr),
						)
					}
				}
			} else {
				// 评论帖子，通知帖子作者
				if postOwnerID != userID {
					notifyErr := s.systemMessageService.SendCommentNotification(context.Background(), postOwnerID, userID, postID, commentID)
					if notifyErr != nil {
						zap.L().Error("Error sending comment notification",
							zap.Error(notifyErr),
						)
					}
				}
			}
		}()
	}

}

func (s *CommentService) notifyCommentModerationRejected(userID, reason string) {
	if s.systemMessageService == nil || strings.TrimSpace(userID) == "" {
		return
	}

	content := "您发布的评论未通过AI审核，请修改后重试。"
	if strings.TrimSpace(reason) != "" {
		content = fmt.Sprintf("您发布的评论未通过AI审核，原因：%s。请修改后重试。", reason)
	}

	go func() {
		if err := s.systemMessageService.SendSystemAnnouncement(
			context.Background(),
			[]string{userID},
			"评论审核未通过",
			content,
		); err != nil {
			zap.L().Warn("Failed to send comment moderation reject notification",
				zap.Error(err),
			)
		}
	}()
}

// GetByID 根据ID获取评论
func (s *CommentService) GetByID(ctx context.Context, id string) (*model.Comment, error) {
	return s.commentRepo.GetByID(id)
}

// GetByPostID 获取帖子评论
func (s *CommentService) GetByPostID(ctx context.Context, postID string, page, pageSize int) ([]*model.Comment, int64, error) {
	// 使用带回复的查询，默认加载前3条回复
	return s.commentRepo.GetByPostIDWithReplies(postID, page, pageSize, 3)
}

// GetRepliesByRootID 根据根评论ID分页获取回复
func (s *CommentService) GetRepliesByRootID(ctx context.Context, rootID string, page, pageSize int) ([]*model.Comment, int64, error) {
	return s.commentRepo.GetRepliesByRootID(rootID, page, pageSize)
}

// GetReplies 获取回复
func (s *CommentService) GetReplies(ctx context.Context, parentID string) ([]*model.Comment, error) {
	return s.commentRepo.GetReplies(parentID)
}

// Update 更新评论
func (s *CommentService) Update(ctx context.Context, userID string, comment *model.Comment) error {
	if comment.UserID != userID {
		return apperrors.ErrForbidden
	}
	return s.commentRepo.Update(comment)
}

// Delete 删除评论
func (s *CommentService) Delete(ctx context.Context, userID string, id string) error {
	comment, err := s.commentRepo.GetByID(id)
	if err != nil {
		return err
	}
	if comment.UserID != userID {
		return apperrors.ErrForbidden
	}
	if err := s.commentRepo.Delete(id); err != nil {
		return err
	}
	s.invalidatePostCaches(comment.PostID)
	return nil
}

// Like 点赞评论
func (s *CommentService) Like(ctx context.Context, commentID, userID string) error {
	// 获取评论信息用于发送通知
	comment, err := s.commentRepo.GetByID(commentID)
	if err != nil {
		return err
	}

	err = s.commentRepo.Like(commentID, userID)
	if err != nil {
		return err
	}

	// 发送评论/回复点赞通知（只有不是给自己点赞时才发送）
	if s.systemMessageService != nil && comment.UserID != userID {
		go func() {
			var notifyErr error
			if comment.ParentID != nil {
				notifyErr = s.systemMessageService.SendLikeReplyNotification(
					context.Background(),
					comment.UserID,
					userID,
					comment.PostID,
					commentID,
					comment.Content,
				)
			} else {
				notifyErr = s.systemMessageService.SendLikeCommentNotification(
					context.Background(),
					comment.UserID,
					userID,
					comment.PostID,
					commentID,
					comment.Content,
				)
			}
			if notifyErr != nil {
				zap.L().Error("Error sending like notification",
					zap.Error(notifyErr),
				)
			}
		}()
	}

	return nil
}

// Unlike 取消点赞评论
func (s *CommentService) Unlike(ctx context.Context, commentID, userID string) error {
	return s.commentRepo.Unlike(commentID, userID)
}

// IsLiked 检查是否已点赞
func (s *CommentService) IsLiked(ctx context.Context, commentID, userID string) bool {
	return s.commentRepo.IsLiked(commentID, userID)
}

// GetCommentsByCursor 游标分页获取帖子评论
func (s *CommentService) GetCommentsByCursor(ctx context.Context, postID string, req *cursor.PageRequest) (*cursor.CursorPageResult[*model.Comment], error) {
	return s.commentRepo.GetCommentsByCursor(ctx, postID, req)
}

// GetRepliesByCursor 游标分页获取根评论的回复
func (s *CommentService) GetRepliesByCursor(ctx context.Context, rootID string, req *cursor.PageRequest) (*cursor.CursorPageResult[*model.Comment], error) {
	return s.commentRepo.GetRepliesByCursor(ctx, rootID, req)
}