backend/internal/pkg/hook/moderation_hooks.go

package hook

import (
	"context"
	"strings"
	"time"

	"carrot_bbs/internal/repository"

	"go.uber.org/zap"
)

type reviewableError interface {
	IsReview() bool
}

type PostAIService interface {
	IsEnabled() bool
	ModeratePost(ctx context.Context, title, content string, images []string) error
	ModerateComment(ctx context.Context, content string, images []string) error
}

type PostModerationHook struct {
	name          string
	postAIService PostAIService
	postRepo      repository.PostRepository
	strictMode    bool
}

func NewPostModerationHook(postAIService PostAIService, postRepo repository.PostRepository, strictMode bool) *PostModerationHook {
	return &PostModerationHook{
		name:          "moderation.post.ai",
		postAIService: postAIService,
		postRepo:      postRepo,
		strictMode:    strictMode,
	}
}

func (h *PostModerationHook) Register(manager *Manager) {
	manager.Register(&Hook{
		Name:     h.name,
		HookType: HookPostPreModerate,
		Priority: PriorityHigh,
		Func:     h.Execute,
		Async:    false,
		Timeout:  30 * time.Second,
	})
}

func (h *PostModerationHook) Execute(ctx *HookContext) error {
	data, ok := ctx.Data.(*PostModerateHookData)
	if !ok {
		return nil
	}

	result, ok := ctx.Metadata["result"].(*ModerationResult)
	if !ok || result == nil {
		return nil
	}

	if result.RejectReason != "" || result.NeedsReview {
		return nil
	}

	if h.postAIService == nil || !h.postAIService.IsEnabled() {
		result.Approved = true
		result.ReviewedBy = "system"
		return nil
	}

	err := h.postAIService.ModeratePost(ctx.Ctx, data.Title, data.Content, data.Images)
	if err != nil {
		if userErr, ok := err.(interface{ UserMessage() string }); ok {
			if revErr, ok := err.(reviewableError); ok && revErr.IsReview() {
				result.Approved = false
				result.NeedsReview = true
				result.RejectReason = userErr.UserMessage()
				result.ReviewedBy = "ai"
				zap.L().Info("Post flagged for manual review by AI",
					zap.String("post_id", data.PostID),
					zap.String("reason", result.RejectReason),
				)
				return nil
			}
			result.Approved = false
			result.RejectReason = userErr.UserMessage()
			result.ReviewedBy = "ai"
			zap.L().Info("Post rejected by AI moderation",
				zap.String("post_id", data.PostID),
				zap.String("reason", result.RejectReason),
			)
			return nil
		}

		if h.strictMode {
			result.Approved = false
			result.Error = err
			result.ReviewedBy = "ai"
			zap.L().Error("AI post moderation failed in strict mode, reject post",
				zap.String("post_id", data.PostID),
				zap.Error(err),
			)
			return nil
		}

		result.Approved = true
		result.ReviewedBy = "system"
		zap.L().Warn("AI moderation error, fallback approve",
			zap.String("post_id", data.PostID),
			zap.Error(err),
		)
		return nil
	}

	result.Approved = true
	result.ReviewedBy = "ai"
	return nil
}

type CommentModerationHook struct {
	name          string
	postAIService PostAIService
	commentRepo   repository.CommentRepository
	strictMode    bool
}

func NewCommentModerationHook(postAIService PostAIService, commentRepo repository.CommentRepository, strictMode bool) *CommentModerationHook {
	return &CommentModerationHook{
		name:          "moderation.comment.ai",
		postAIService: postAIService,
		commentRepo:   commentRepo,
		strictMode:    strictMode,
	}
}

func (h *CommentModerationHook) Register(manager *Manager) {
	manager.Register(&Hook{
		Name:     h.name,
		HookType: HookCommentPreModerate,
		Priority: PriorityHigh,
		Func:     h.Execute,
		Async:    false,
		Timeout:  30 * time.Second,
	})
}

func (h *CommentModerationHook) Execute(ctx *HookContext) error {
	data, ok := ctx.Data.(*CommentModerateHookData)
	if !ok {
		return nil
	}

	result, ok := ctx.Metadata["result"].(*ModerationResult)
	if !ok || result == nil {
		return nil
	}

	if result.RejectReason != "" || result.NeedsReview {
		return nil
	}

	if h.postAIService == nil || !h.postAIService.IsEnabled() {
		result.Approved = true
		result.ReviewedBy = "system"
		return nil
	}

	err := h.postAIService.ModerateComment(ctx.Ctx, data.Content, data.Images)
	if err != nil {
		if userErr, ok := err.(interface{ UserMessage() string }); ok {
			if revErr, ok := err.(reviewableError); ok && revErr.IsReview() {
				result.Approved = false
				result.NeedsReview = true
				result.RejectReason = userErr.UserMessage()
				result.ReviewedBy = "ai"
				zap.L().Info("Comment flagged for manual review by AI",
					zap.String("comment_id", data.CommentID),
					zap.String("reason", result.RejectReason),
				)
				return nil
			}
			result.Approved = false
			result.RejectReason = userErr.UserMessage()
			result.ReviewedBy = "ai"
			zap.L().Info("Comment rejected by AI moderation",
				zap.String("comment_id", data.CommentID),
				zap.String("reason", result.RejectReason),
			)
			return nil
		}

		if h.strictMode {
			result.Approved = false
			result.Error = err
			result.ReviewedBy = "ai"
			zap.L().Error("AI comment moderation failed in strict mode, reject comment",
				zap.String("comment_id", data.CommentID),
				zap.Error(err),
			)
			return nil
		}

		result.Approved = true
		result.ReviewedBy = "system"
		zap.L().Warn("AI moderation error, fallback approve",
			zap.String("comment_id", data.CommentID),
			zap.Error(err),
		)
		return nil
	}

	result.Approved = true
	result.ReviewedBy = "ai"
	return nil
}

type SensitiveService interface {
	Check(ctx context.Context, text string) (bool, []string)
	Replace(ctx context.Context, text string, repl string) string
}

type SensitiveWordHook struct {
	name       string
	sensitive  SensitiveService
	replaceStr string
}

func NewSensitiveWordHook(sensitive SensitiveService, replaceStr string) *SensitiveWordHook {
	return &SensitiveWordHook{
		name:       "moderation.sensitive_word",
		sensitive:  sensitive,
		replaceStr: replaceStr,
	}
}

func (h *SensitiveWordHook) RegisterPostHook(manager *Manager) {
	manager.Register(&Hook{
		Name:     h.name + ".post",
		HookType: HookPostPreModerate,
		Priority: PriorityHighest,
		Func:     h.executePost,
		Async:    false,
	})
}

func (h *SensitiveWordHook) RegisterCommentHook(manager *Manager) {
	manager.Register(&Hook{
		Name:     h.name + ".comment",
		HookType: HookCommentPreModerate,
		Priority: PriorityHighest,
		Func:     h.executeComment,
		Async:    false,
	})
}

func (h *SensitiveWordHook) executePost(ctx *HookContext) error {
	if h.sensitive == nil {
		return nil
	}

	data, ok := ctx.Data.(*PostModerateHookData)
	if !ok {
		return nil
	}

	result, ok := ctx.Metadata["result"].(*ModerationResult)
	if !ok || result == nil {
		return nil
	}

	if result.RejectReason != "" {
		return nil
	}

	hasSensitive, words := h.sensitive.Check(ctx.Ctx, data.Title+" "+data.Content)
	if hasSensitive {
		result.Approved = false
		result.RejectReason = "内容包含敏感词: " + strings.Join(words, ", ")
		result.ReviewedBy = "sensitive_word"
		zap.L().Info("Post rejected by sensitive word filter",
			zap.String("post_id", data.PostID),
			zap.Strings("words", words),
		)
	}

	return nil
}

func (h *SensitiveWordHook) executeComment(ctx *HookContext) error {
	if h.sensitive == nil {
		return nil
	}

	data, ok := ctx.Data.(*CommentModerateHookData)
	if !ok {
		return nil
	}

	result, ok := ctx.Metadata["result"].(*ModerationResult)
	if !ok || result == nil {
		return nil
	}

	if result.RejectReason != "" {
		return nil
	}

	hasSensitive, words := h.sensitive.Check(ctx.Ctx, data.Content)
	if hasSensitive {
		result.Approved = false
		result.RejectReason = "内容包含敏感词: " + strings.Join(words, ", ")
		result.ReviewedBy = "sensitive_word"
		zap.L().Info("Comment rejected by sensitive word filter",
			zap.String("comment_id", data.CommentID),
			zap.Strings("words", words),
		)
	}

	return nil
}

type ModerationHooks struct {
	postAIService    PostAIService
	sensitiveService SensitiveService
	postRepo         repository.PostRepository
	commentRepo      repository.CommentRepository
	strictMode       bool
	replaceStr       string
}

func NewModerationHooks(
	postAIService PostAIService,
	sensitiveService SensitiveService,
	postRepo repository.PostRepository,
	commentRepo repository.CommentRepository,
	strictMode bool,
	replaceStr string,
) *ModerationHooks {
	return &ModerationHooks{
		postAIService:    postAIService,
		sensitiveService: sensitiveService,
		postRepo:         postRepo,
		commentRepo:      commentRepo,
		strictMode:       strictMode,
		replaceStr:       replaceStr,
	}
}

func (m *ModerationHooks) RegisterAll(manager *Manager) {
	if m.sensitiveService != nil {
		sensitiveHook := NewSensitiveWordHook(m.sensitiveService, m.replaceStr)
		sensitiveHook.RegisterPostHook(manager)
		sensitiveHook.RegisterCommentHook(manager)
	}

	postHook := NewPostModerationHook(m.postAIService, m.postRepo, m.strictMode)
	postHook.Register(manager)

	commentHook := NewCommentModerationHook(m.postAIService, m.commentRepo, m.strictMode)
	commentHook.Register(manager)

	zap.L().Info("Registered moderation hooks",
		zap.Bool("ai_enabled", m.postAIService != nil && m.postAIService.IsEnabled()),
		zap.Bool("sensitive_enabled", m.sensitiveService != nil),
		zap.Bool("strict_mode", m.strictMode),
	)
}

func (m *ModerationHooks) ModeratePost(ctx context.Context, manager *Manager, data *PostModerateHookData) *ModerationResult {
	result := &ModerationResult{}
	manager.TriggerWithMetadata(ctx, HookPostPreModerate, data.AuthorID, data, map[string]any{
		"result": result,
	})
	return result
}

func (m *ModerationHooks) ModerateComment(ctx context.Context, manager *Manager, data *CommentModerateHookData) *ModerationResult {
	result := &ModerationResult{}
	manager.TriggerWithMetadata(ctx, HookCommentPreModerate, data.AuthorID, data, map[string]any{
		"result": result,
	})
	return result
}