backend/internal/service/report_service.go

package service

import (
	"context"
	"errors"
	"fmt"

	"with_you/internal/config"
	"with_you/internal/model"
	"with_you/internal/repository"

	"go.uber.org/zap"
)

// ReportService 举报服务接口（用户端）
type ReportService interface {
	// CreateReport 创建举报
	CreateReport(ctx context.Context, reporterID, targetType, targetID, reason, description string) (*model.Report, error)
	// HasUserReported 检查用户是否已举报
	HasUserReported(ctx context.Context, reporterID, targetType, targetID string) (bool, error)
}

// reportServiceImpl 举报服务实现
type reportServiceImpl struct {
	reportRepo  repository.ReportRepository
	postRepo    repository.PostRepository
	commentRepo repository.CommentRepository
	messageRepo repository.MessageRepository
	userRepo    repository.UserRepository
	notifyRepo  repository.SystemNotificationRepository
	pushService PushService
	txManager   repository.TransactionManager
	logService  OperationLogService
	config      *config.ReportConfig
}

// NewReportService 创建举报服务
func NewReportService(
	reportRepo repository.ReportRepository,
	postRepo repository.PostRepository,
	commentRepo repository.CommentRepository,
	messageRepo repository.MessageRepository,
	userRepo repository.UserRepository,
	notifyRepo repository.SystemNotificationRepository,
	pushService PushService,
	txManager repository.TransactionManager,
	logService OperationLogService,
	cfg *config.Config,
) ReportService {
	reportConfig := &cfg.Report
	if reportConfig.AutoHideThreshold == 0 {
		reportConfig.AutoHideThreshold = 3
	}
	return &reportServiceImpl{
		reportRepo:  reportRepo,
		postRepo:    postRepo,
		commentRepo: commentRepo,
		messageRepo: messageRepo,
		userRepo:    userRepo,
		notifyRepo:  notifyRepo,
		pushService: pushService,
		txManager:   txManager,
		logService:  logService,
		config:      reportConfig,
	}
}

// CreateReport 创建举报
func (s *reportServiceImpl) CreateReport(ctx context.Context, reporterID, targetType, targetID, reason, description string) (*model.Report, error) {
	// 验证举报类型
	reportTargetType := model.ReportTargetType(targetType)
	if reportTargetType != model.ReportTargetTypePost &&
		reportTargetType != model.ReportTargetTypeComment &&
		reportTargetType != model.ReportTargetTypeMessage {
		return nil, errors.New("invalid target type")
	}

	// 验证举报原因
	reportReason := model.ReportReason(reason)
	if reportReason != model.ReportReasonSpam &&
		reportReason != model.ReportReasonInappropriate &&
		reportReason != model.ReportReasonHarassment &&
		reportReason != model.ReportReasonMisinformation &&
		reportReason != model.ReportReasonOther {
		return nil, errors.New("invalid reason")
	}

	// 检查目标内容是否存在
	if err := s.validateTargetExists(ctx, reportTargetType, targetID); err != nil {
		return nil, err
	}

	// 检查用户是否已举报过
	hasReported, err := s.reportRepo.HasUserReported(reporterID, reportTargetType, targetID)
	if err != nil {
		zap.L().Error("failed to check if user has reported", zap.Error(err))
		return nil, errors.New("failed to check report status")
	}
	if hasReported {
		return nil, errors.New("you have already reported this content")
	}

	// 创建举报
	report := &model.Report{
		ReporterID:  reporterID,
		TargetType:  reportTargetType,
		TargetID:    targetID,
		Reason:      reportReason,
		Description: description,
		Status:      model.ReportStatusPending,
	}

	// 使用事务处理
	var createdReport *model.Report
	err = s.txManager.RunInTransaction(ctx, func(ctx context.Context) error {
		// 创建举报记录
		if err := s.reportRepo.CreateWithContext(ctx, report); err != nil {
			return fmt.Errorf("failed to create report: %w", err)
		}

		createdReport = report

		// 检查举报次数是否达到阈值
		count, err := s.reportRepo.GetReportCount(reportTargetType, targetID)
		if err != nil {
			zap.L().Error("failed to get report count", zap.Error(err))
			return nil // 不阻止举报创建
		}

		// 达到阈值，自动隐藏内容
		if int(count) >= s.config.AutoHideThreshold {
			if err := s.hideTargetContent(ctx, reportTargetType, targetID); err != nil {
				zap.L().Error("failed to hide target content", zap.Error(err))
				return nil // 不阻止举报创建
			}
			zap.L().Info("content auto-hidden due to report threshold",
				zap.String("target_type", targetType),
				zap.String("target_id", targetID),
				zap.Int64("report_count", count),
			)
		}

		return nil
	})

	if err != nil {
		return nil, err
	}

	// 记录操作日志
	if s.logService != nil {
		s.logService.RecordOperation(&model.OperationLog{
			UserID:     reporterID,
			Operation:  "create_report",
			TargetType: "report",
			TargetID:   report.ID,
			Module:     "report",
		})
	}

	return createdReport, nil
}

// HasUserReported 检查用户是否已举报
func (s *reportServiceImpl) HasUserReported(ctx context.Context, reporterID, targetType, targetID string) (bool, error) {
	return s.reportRepo.HasUserReported(reporterID, model.ReportTargetType(targetType), targetID)
}

// validateTargetExists 验证目标内容是否存在
func (s *reportServiceImpl) validateTargetExists(ctx context.Context, targetType model.ReportTargetType, targetID string) error {
	switch targetType {
	case model.ReportTargetTypePost:
		post, err := s.postRepo.GetByID(targetID)
		if err != nil || post == nil {
			return errors.New("post not found")
		}
	case model.ReportTargetTypeComment:
		comment, err := s.commentRepo.GetByID(targetID)
		if err != nil || comment == nil {
			return errors.New("comment not found")
		}
	case model.ReportTargetTypeMessage:
		_, err := s.messageRepo.GetMessageByID(targetID)
		if err != nil {
			return errors.New("message not found")
		}
	}
	return nil
}

// hideTargetContent 隐藏目标内容。
//
// 评论隐藏统一走 commentRepo.UpdateModerationStatus(published → deleted)，
// 经由仓储内的统一状态转换层维护 posts.comments_count / comments.replies_count，
// 避免此前用裸 Update 改 status 导致举报自动隐藏后计数漏减的问题。
func (s *reportServiceImpl) hideTargetContent(ctx context.Context, targetType model.ReportTargetType, targetID string) error {
	switch targetType {
	case model.ReportTargetTypePost:
		post, err := s.postRepo.GetByID(targetID)
		if err != nil {
			return err
		}
		if post != nil && post.Status != model.PostStatusDeleted {
			post.Status = model.PostStatusDeleted
			return s.postRepo.Update(post)
		}
	case model.ReportTargetTypeComment:
		comment, err := s.commentRepo.GetByID(targetID)
		if err != nil {
			return err
		}
		// 已是终态（deleted/rejected 等非 published）无需再隐藏，也避免重复调整计数
		if comment == nil || comment.Status != model.CommentStatusPublished {
			return nil
		}
		// published → deleted：统一状态转换层会原子维护计数（永不为负）
		if _, err := s.commentRepo.UpdateModerationStatus(targetID, model.CommentStatusDeleted, "举报自动隐藏", "system"); err != nil {
			return err
		}
	case model.ReportTargetTypeMessage:
		// 消息隐藏通过更新状态实现
		return s.messageRepo.UpdateMessageStatus(targetID, model.MessageStatusDeleted)
	}
	return nil
}