backend/internal/service/comment_service.go

package service

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

	"carrot_bbs/internal/cache"
	"carrot_bbs/internal/model"
	"carrot_bbs/internal/pkg/gorse"
	"carrot_bbs/internal/repository"
)

// CommentService 评论服务
type CommentService struct {
	commentRepo          *repository.CommentRepository
	postRepo             *repository.PostRepository
	systemMessageService SystemMessageService
	cache                cache.Cache
	gorseClient          gorse.Client
	postAIService        *PostAIService
}

// NewCommentService 创建评论服务
func NewCommentService(commentRepo *repository.CommentRepository, postRepo *repository.PostRepository, systemMessageService SystemMessageService, gorseClient gorse.Client, postAIService *PostAIService) *CommentService {
	return &CommentService{
		commentRepo:          commentRepo,
		postRepo:             postRepo,
		systemMessageService: systemMessageService,
		cache:                cache.GetCache(),
		gorseClient:          gorseClient,
		postAIService:        postAIService,
	}
}

// Create 创建评论
func (s *CommentService) Create(ctx context.Context, postID, userID, content string, 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,
		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
	}

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

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

	return comment, nil
}

func (s *CommentService) reviewCommentAsync(
	commentID, userID, postID, content string,
	imageURLs []string,
	parentID *string,
	parentUserID string,
	postOwnerID string,
) {
	// 未启用AI时，直接通过审核并发送后续通知
	if s.postAIService == nil || !s.postAIService.IsEnabled() {
		if err := s.commentRepo.UpdateModerationStatus(commentID, model.CommentStatusPublished); err != nil {
			log.Printf("[WARN] Failed to publish comment without AI moderation: %v", err)
			return
		}
		if err := s.applyCommentPublishedStats(commentID); err != nil {
			log.Printf("[WARN] Failed to apply published stats for comment %s: %v", commentID, err)
		}
		s.invalidatePostCaches(postID)
		s.afterCommentPublished(userID, postID, commentID, parentID, parentUserID, postOwnerID)
		return
	}

	err := s.postAIService.ModerateComment(context.Background(), content, imageURLs)
	if err != nil {
		var rejectedErr *CommentModerationRejectedError
		if errors.As(err, &rejectedErr) {
			if delErr := s.commentRepo.Delete(commentID); delErr != nil {
				log.Printf("[WARN] Failed to delete rejected comment %s: %v", commentID, delErr)
			}
			s.notifyCommentModerationRejected(userID, rejectedErr.Reason)
			return
		}

		// 审核服务异常时降级放行，避免评论长期pending
		if updateErr := s.commentRepo.UpdateModerationStatus(commentID, model.CommentStatusPublished); updateErr != nil {
			log.Printf("[WARN] Failed to publish comment %s after moderation error: %v", commentID, updateErr)
			return
		}
		if statsErr := s.applyCommentPublishedStats(commentID); statsErr != nil {
			log.Printf("[WARN] Failed to apply published stats for comment %s: %v", commentID, statsErr)
		}
		s.invalidatePostCaches(postID)
		log.Printf("[WARN] Comment moderation failed, fallback publish comment=%s err=%v", commentID, err)
		s.afterCommentPublished(userID, postID, commentID, parentID, parentUserID, postOwnerID)
		return
	}

	if updateErr := s.commentRepo.UpdateModerationStatus(commentID, model.CommentStatusPublished); updateErr != nil {
		log.Printf("[WARN] Failed to publish comment %s: %v", commentID, updateErr)
		return
	}
	if statsErr := s.applyCommentPublishedStats(commentID); statsErr != nil {
		log.Printf("[WARN] Failed to apply published stats for comment %s: %v", commentID, 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 {
						log.Printf("[ERROR] Error sending reply notification: %v", 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 {
						log.Printf("[ERROR] Error sending comment notification: %v", notifyErr)
					}
				}
			}
		}()
	}

	// 推送评论行为到Gorse（异步）
	go func() {
		if s.gorseClient.IsEnabled() {
			if err := s.gorseClient.InsertFeedback(context.Background(), gorse.FeedbackTypeComment, userID, postID); err != nil {
				log.Printf("[WARN] Failed to insert comment feedback to Gorse: %v", err)
			}
		}
	}()
}

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 {
			log.Printf("[WARN] Failed to send comment moderation reject notification: %v", 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, comment *model.Comment) error {
	return s.commentRepo.Update(comment)
}

// Delete 删除评论
func (s *CommentService) Delete(ctx context.Context, id string) error {
	comment, err := s.commentRepo.GetByID(id)
	if err != nil {
		return err
	}
	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 {
				log.Printf("[ERROR] Error sending like notification: %v", 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)
}