backend/internal/dto/converter.go

package dto

import (
	"carrot_bbs/internal/model"
	"carrot_bbs/internal/pkg/utils"
	"context"
	"encoding/json"
	"strconv"
)

// ==================== User 转换 ====================

// getAvatarOrDefault 获取头像URL，如果为空则返回在线头像生成服务的URL
func getAvatarOrDefault(user *model.User) string {
	return utils.GetAvatarOrDefault(user.Username, user.Nickname, user.Avatar)
}

// ConvertUserToResponse 将User转换为UserResponse
func ConvertUserToResponse(user *model.User) *UserResponse {
	if user == nil {
		return nil
	}
	return &UserResponse{
		ID:             user.ID,
		Username:       user.Username,
		Nickname:       user.Nickname,
		Email:          user.Email,
		Phone:          user.Phone,
		EmailVerified:  user.EmailVerified,
		Avatar:         getAvatarOrDefault(user),
		CoverURL:       user.CoverURL,
		Bio:            user.Bio,
		Website:        user.Website,
		Location:       user.Location,
		PostsCount:     user.PostsCount,
		FollowersCount: user.FollowersCount,
		FollowingCount: user.FollowingCount,
		CreatedAt:      FormatTime(user.CreatedAt),
	}
}

// ConvertUserToResponseWithFollowing 将User转换为UserResponse（包含关注状态）
func ConvertUserToResponseWithFollowing(user *model.User, isFollowing bool) *UserResponse {
	if user == nil {
		return nil
	}
	return &UserResponse{
		ID:             user.ID,
		Username:       user.Username,
		Nickname:       user.Nickname,
		Email:          user.Email,
		Phone:          user.Phone,
		EmailVerified:  user.EmailVerified,
		Avatar:         getAvatarOrDefault(user),
		CoverURL:       user.CoverURL,
		Bio:            user.Bio,
		Website:        user.Website,
		Location:       user.Location,
		PostsCount:     user.PostsCount,
		FollowersCount: user.FollowersCount,
		FollowingCount: user.FollowingCount,
		IsFollowing:    isFollowing,
		IsFollowingMe:  false, // 默认false，需要单独计算
		CreatedAt:      FormatTime(user.CreatedAt),
	}
}

// ConvertUserToResponseWithPostsCount 将User转换为UserResponse（使用实时计算的帖子数量）
func ConvertUserToResponseWithPostsCount(user *model.User, postsCount int) *UserResponse {
	if user == nil {
		return nil
	}
	return &UserResponse{
		ID:             user.ID,
		Username:       user.Username,
		Nickname:       user.Nickname,
		Email:          user.Email,
		Phone:          user.Phone,
		EmailVerified:  user.EmailVerified,
		Avatar:         getAvatarOrDefault(user),
		CoverURL:       user.CoverURL,
		Bio:            user.Bio,
		Website:        user.Website,
		Location:       user.Location,
		PostsCount:     postsCount,
		FollowersCount: user.FollowersCount,
		FollowingCount: user.FollowingCount,
		CreatedAt:      FormatTime(user.CreatedAt),
	}
}

// ConvertUserToResponseWithMutualFollow 将User转换为UserResponse（包含双向关注状态）
func ConvertUserToResponseWithMutualFollow(user *model.User, isFollowing, isFollowingMe bool) *UserResponse {
	if user == nil {
		return nil
	}
	return &UserResponse{
		ID:             user.ID,
		Username:       user.Username,
		Nickname:       user.Nickname,
		Email:          user.Email,
		Phone:          user.Phone,
		EmailVerified:  user.EmailVerified,
		Avatar:         getAvatarOrDefault(user),
		CoverURL:       user.CoverURL,
		Bio:            user.Bio,
		Website:        user.Website,
		Location:       user.Location,
		PostsCount:     user.PostsCount,
		FollowersCount: user.FollowersCount,
		FollowingCount: user.FollowingCount,
		IsFollowing:    isFollowing,
		IsFollowingMe:  isFollowingMe,
		CreatedAt:      FormatTime(user.CreatedAt),
	}
}

// ConvertUserToResponseWithMutualFollowAndPostsCount 将User转换为UserResponse（包含双向关注状态和实时计算的帖子数量）
func ConvertUserToResponseWithMutualFollowAndPostsCount(user *model.User, isFollowing, isFollowingMe bool, postsCount int) *UserResponse {
	if user == nil {
		return nil
	}
	return &UserResponse{
		ID:             user.ID,
		Username:       user.Username,
		Nickname:       user.Nickname,
		Email:          user.Email,
		Phone:          user.Phone,
		EmailVerified:  user.EmailVerified,
		Avatar:         getAvatarOrDefault(user),
		CoverURL:       user.CoverURL,
		Bio:            user.Bio,
		Website:        user.Website,
		Location:       user.Location,
		PostsCount:     postsCount,
		FollowersCount: user.FollowersCount,
		FollowingCount: user.FollowingCount,
		IsFollowing:    isFollowing,
		IsFollowingMe:  isFollowingMe,
		CreatedAt:      FormatTime(user.CreatedAt),
	}
}

// ConvertUserToDetailResponse 将User转换为UserDetailResponse
func ConvertUserToDetailResponse(user *model.User) *UserDetailResponse {
	if user == nil {
		return nil
	}
	return &UserDetailResponse{
		ID:             user.ID,
		Username:       user.Username,
		Nickname:       user.Nickname,
		Email:          user.Email,
		EmailVerified:  user.EmailVerified,
		Avatar:         getAvatarOrDefault(user),
		CoverURL:       user.CoverURL,
		Bio:            user.Bio,
		Website:        user.Website,
		Location:       user.Location,
		PostsCount:     user.PostsCount,
		FollowersCount: user.FollowersCount,
		FollowingCount: user.FollowingCount,
		IsVerified:     user.IsVerified,
		CreatedAt:      FormatTime(user.CreatedAt),
	}
}

// ConvertUserToDetailResponseWithPostsCount 将User转换为UserDetailResponse（使用实时计算的帖子数量）
func ConvertUserToDetailResponseWithPostsCount(user *model.User, postsCount int) *UserDetailResponse {
	if user == nil {
		return nil
	}
	return &UserDetailResponse{
		ID:             user.ID,
		Username:       user.Username,
		Nickname:       user.Nickname,
		Email:          user.Email,
		EmailVerified:  user.EmailVerified,
		Phone:          user.Phone, // 仅当前用户自己可见
		Avatar:         getAvatarOrDefault(user),
		CoverURL:       user.CoverURL,
		Bio:            user.Bio,
		Website:        user.Website,
		Location:       user.Location,
		PostsCount:     postsCount,
		FollowersCount: user.FollowersCount,
		FollowingCount: user.FollowingCount,
		IsVerified:     user.IsVerified,
		CreatedAt:      FormatTime(user.CreatedAt),
	}
}

// ConvertUsersToResponse 将User列表转换为响应列表
func ConvertUsersToResponse(users []*model.User) []*UserResponse {
	result := make([]*UserResponse, 0, len(users))
	for _, user := range users {
		result = append(result, ConvertUserToResponse(user))
	}
	return result
}

// ConvertUsersToResponseWithMutualFollow 将User列表转换为响应列表（包含双向关注状态）
// followingStatusMap: key是用户ID，value是[isFollowing, isFollowingMe]
func ConvertUsersToResponseWithMutualFollow(users []*model.User, followingStatusMap map[string][2]bool) []*UserResponse {
	result := make([]*UserResponse, 0, len(users))
	for _, user := range users {
		status, ok := followingStatusMap[user.ID]
		if ok {
			result = append(result, ConvertUserToResponseWithMutualFollow(user, status[0], status[1]))
		} else {
			result = append(result, ConvertUserToResponse(user))
		}
	}
	return result
}

// ConvertUsersToResponseWithMutualFollowAndPostsCount 将User列表转换为响应列表（包含双向关注状态和实时计算的帖子数量）
// followingStatusMap: key是用户ID，value是[isFollowing, isFollowingMe]
// postsCountMap: key是用户ID，value是帖子数量
func ConvertUsersToResponseWithMutualFollowAndPostsCount(users []*model.User, followingStatusMap map[string][2]bool, postsCountMap map[string]int64) []*UserResponse {
	result := make([]*UserResponse, 0, len(users))
	for _, user := range users {
		status, hasStatus := followingStatusMap[user.ID]
		postsCount, hasPostsCount := postsCountMap[user.ID]

		// 如果没有帖子数量，使用数据库中的值
		if !hasPostsCount {
			postsCount = int64(user.PostsCount)
		}

		if hasStatus {
			result = append(result, ConvertUserToResponseWithMutualFollowAndPostsCount(user, status[0], status[1], int(postsCount)))
		} else {
			result = append(result, ConvertUserToResponseWithPostsCount(user, int(postsCount)))
		}
	}
	return result
}

// ==================== Post 转换 ====================

// ConvertPostImageToResponse 将PostImage转换为PostImageResponse
func ConvertPostImageToResponse(img *model.PostImage) PostImageResponse {
	if img == nil {
		return PostImageResponse{}
	}
	return PostImageResponse{
		ID:           img.ID,
		URL:          img.URL,
		ThumbnailURL: img.ThumbnailURL,
		Width:        img.Width,
		Height:       img.Height,
	}
}

// ConvertPostImagesToResponse 将PostImage列表转换为响应列表
func ConvertPostImagesToResponse(images []model.PostImage) []PostImageResponse {
	result := make([]PostImageResponse, 0, len(images))
	for i := range images {
		result = append(result, ConvertPostImageToResponse(&images[i]))
	}
	return result
}

// ConvertPostToResponse 将Post转换为PostResponse（列表用）
func ConvertPostToResponse(post *model.Post, isLiked, isFavorited bool) *PostResponse {
	if post == nil {
		return nil
	}

	images := make([]PostImageResponse, 0)
	for _, img := range post.Images {
		images = append(images, ConvertPostImageToResponse(&img))
	}

	var author *UserResponse
	if post.User != nil {
		author = ConvertUserToResponse(post.User)
	}

	return &PostResponse{
		ID:             post.ID,
		UserID:         post.UserID,
		Title:          post.Title,
		Content:        post.Content,
		Images:         images,
		Status:         string(post.Status),
		LikesCount:     post.LikesCount,
		CommentsCount:  post.CommentsCount,
		FavoritesCount: post.FavoritesCount,
		SharesCount:    post.SharesCount,
		ViewsCount:     post.ViewsCount,
		IsPinned:       post.IsPinned,
		IsLocked:       post.IsLocked,
		IsVote:         post.IsVote,
		CreatedAt:      FormatTime(post.CreatedAt),
		UpdatedAt:      FormatTime(post.UpdatedAt),
		Author:         author,
		IsLiked:        isLiked,
		IsFavorited:    isFavorited,
	}
}

// ConvertPostToDetailResponse 将Post转换为PostDetailResponse
func ConvertPostToDetailResponse(post *model.Post, isLiked, isFavorited bool) *PostDetailResponse {
	if post == nil {
		return nil
	}

	images := make([]PostImageResponse, 0)
	for _, img := range post.Images {
		images = append(images, ConvertPostImageToResponse(&img))
	}

	var author *UserResponse
	if post.User != nil {
		author = ConvertUserToResponse(post.User)
	}

	return &PostDetailResponse{
		ID:             post.ID,
		UserID:         post.UserID,
		Title:          post.Title,
		Content:        post.Content,
		Images:         images,
		Status:         string(post.Status),
		LikesCount:     post.LikesCount,
		CommentsCount:  post.CommentsCount,
		FavoritesCount: post.FavoritesCount,
		SharesCount:    post.SharesCount,
		ViewsCount:     post.ViewsCount,
		IsPinned:       post.IsPinned,
		IsLocked:       post.IsLocked,
		IsVote:         post.IsVote,
		CreatedAt:      FormatTime(post.CreatedAt),
		UpdatedAt:      FormatTime(post.UpdatedAt),
		Author:         author,
		IsLiked:        isLiked,
		IsFavorited:    isFavorited,
	}
}

// ConvertPostsToResponse 将Post列表转换为响应列表（每个帖子独立检查点赞/收藏状态）
func ConvertPostsToResponse(posts []*model.Post, isLikedMap, isFavoritedMap map[string]bool) []*PostResponse {
	result := make([]*PostResponse, 0, len(posts))
	for _, post := range posts {
		isLiked := false
		isFavorited := false
		if isLikedMap != nil {
			isLiked = isLikedMap[post.ID]
		}
		if isFavoritedMap != nil {
			isFavorited = isFavoritedMap[post.ID]
		}
		result = append(result, ConvertPostToResponse(post, isLiked, isFavorited))
	}
	return result
}

// BuildPostResponse 构建单个帖子响应（包含交互状态）
// 这是一个语义化的辅助函数，便于 Handler 层调用
func BuildPostResponse(post *model.Post, isLiked, isFavorited bool) *PostResponse {
	return ConvertPostToResponse(post, isLiked, isFavorited)
}

// BuildPostsWithInteractionResponse 批量构建帖子响应（包含交互状态）
// 这是一个语义化的辅助函数，便于 Handler 层调用
func BuildPostsWithInteractionResponse(posts []*model.Post, isLikedMap, isFavoritedMap map[string]bool) []*PostResponse {
	return ConvertPostsToResponse(posts, isLikedMap, isFavoritedMap)
}

// ==================== Comment 转换 ====================

// ConvertCommentToResponse 将Comment转换为CommentResponse
func ConvertCommentToResponse(comment *model.Comment, isLiked bool) *CommentResponse {
	if comment == nil {
		return nil
	}

	var author *UserResponse
	if comment.User != nil {
		author = ConvertUserToResponse(comment.User)
	}

	// 转换子回复（扁平化结构）
	var replies []*CommentResponse
	if len(comment.Replies) > 0 {
		replies = make([]*CommentResponse, 0, len(comment.Replies))
		for _, reply := range comment.Replies {
			replies = append(replies, ConvertCommentToResponse(reply, false))
		}
	}

	// TargetID 就是 ParentID，前端根据这个 ID 找到被回复用户的昵称
	var targetID *string
	if comment.ParentID != nil && *comment.ParentID != "" {
		targetID = comment.ParentID
	}

	// 解析图片JSON
	var images []CommentImageResponse
	if comment.Images != "" {
		var urlList []string
		if err := json.Unmarshal([]byte(comment.Images), &urlList); err == nil {
			images = make([]CommentImageResponse, 0, len(urlList))
			for _, url := range urlList {
				images = append(images, CommentImageResponse{URL: url})
			}
		}
	}

	return &CommentResponse{
		ID:           comment.ID,
		PostID:       comment.PostID,
		UserID:       comment.UserID,
		ParentID:     comment.ParentID,
		RootID:       comment.RootID,
		Content:      comment.Content,
		Images:       images,
		LikesCount:   comment.LikesCount,
		RepliesCount: comment.RepliesCount,
		CreatedAt:    FormatTime(comment.CreatedAt),
		Author:       author,
		IsLiked:      isLiked,
		TargetID:     targetID,
		Replies:      replies,
	}
}

// ConvertCommentsToResponse 将Comment列表转换为响应列表
func ConvertCommentsToResponse(comments []*model.Comment, isLiked bool) []*CommentResponse {
	result := make([]*CommentResponse, 0, len(comments))
	for _, comment := range comments {
		result = append(result, ConvertCommentToResponse(comment, isLiked))
	}
	return result
}

// IsLikedChecker 点赞状态检查器接口
type IsLikedChecker interface {
	IsLiked(ctx context.Context, commentID, userID string) bool
}

// ConvertCommentToResponseWithUser 将Comment转换为CommentResponse（根据用户ID检查点赞状态）
func ConvertCommentToResponseWithUser(comment *model.Comment, userID string, checker IsLikedChecker) *CommentResponse {
	if comment == nil {
		return nil
	}

	// 检查当前用户是否点赞了该评论
	isLiked := false
	if userID != "" && checker != nil {
		isLiked = checker.IsLiked(context.Background(), comment.ID, userID)
	}

	var author *UserResponse
	if comment.User != nil {
		author = ConvertUserToResponse(comment.User)
	}

	// 转换子回复（扁平化结构），递归检查点赞状态
	var replies []*CommentResponse
	if len(comment.Replies) > 0 {
		replies = make([]*CommentResponse, 0, len(comment.Replies))
		for _, reply := range comment.Replies {
			replies = append(replies, ConvertCommentToResponseWithUser(reply, userID, checker))
		}
	}

	// TargetID 就是 ParentID，前端根据这个 ID 找到被回复用户的昵称
	var targetID *string
	if comment.ParentID != nil && *comment.ParentID != "" {
		targetID = comment.ParentID
	}

	// 解析图片JSON
	var images []CommentImageResponse
	if comment.Images != "" {
		var urlList []string
		if err := json.Unmarshal([]byte(comment.Images), &urlList); err == nil {
			images = make([]CommentImageResponse, 0, len(urlList))
			for _, url := range urlList {
				images = append(images, CommentImageResponse{URL: url})
			}
		}
	}

	return &CommentResponse{
		ID:           comment.ID,
		PostID:       comment.PostID,
		UserID:       comment.UserID,
		ParentID:     comment.ParentID,
		RootID:       comment.RootID,
		Content:      comment.Content,
		Images:       images,
		LikesCount:   comment.LikesCount,
		RepliesCount: comment.RepliesCount,
		CreatedAt:    FormatTime(comment.CreatedAt),
		Author:       author,
		IsLiked:      isLiked,
		TargetID:     targetID,
		Replies:      replies,
	}
}

// ConvertCommentsToResponseWithUser 将Comment列表转换为响应列表（根据用户ID检查点赞状态）
func ConvertCommentsToResponseWithUser(comments []*model.Comment, userID string, checker IsLikedChecker) []*CommentResponse {
	result := make([]*CommentResponse, 0, len(comments))
	for _, comment := range comments {
		result = append(result, ConvertCommentToResponseWithUser(comment, userID, checker))
	}
	return result
}

// ==================== Notification 转换 ====================

// ConvertNotificationToResponse 将Notification转换为NotificationResponse
func ConvertNotificationToResponse(notification *model.Notification) *NotificationResponse {
	if notification == nil {
		return nil
	}
	return &NotificationResponse{
		ID:        notification.ID,
		UserID:    notification.UserID,
		Type:      string(notification.Type),
		Title:     notification.Title,
		Content:   notification.Content,
		Data:      notification.Data,
		IsRead:    notification.IsRead,
		CreatedAt: FormatTime(notification.CreatedAt),
	}
}

// ConvertNotificationsToResponse 将Notification列表转换为响应列表
func ConvertNotificationsToResponse(notifications []*model.Notification) []*NotificationResponse {
	result := make([]*NotificationResponse, 0, len(notifications))
	for _, n := range notifications {
		result = append(result, ConvertNotificationToResponse(n))
	}
	return result
}

// ==================== Message 转换 ====================

// ConvertMessageToResponse 将Message转换为MessageResponse
func ConvertMessageToResponse(message *model.Message) *MessageResponse {
	if message == nil {
		return nil
	}

	// 直接使用 segments，不需要解析
	segments := make(model.MessageSegments, len(message.Segments))
	for i, seg := range message.Segments {
		segments[i] = model.MessageSegment{
			Type: seg.Type,
			Data: seg.Data,
		}
	}

	return &MessageResponse{
		ID:             message.ID,
		ConversationID: message.ConversationID,
		SenderID:       message.SenderID,
		Seq:            message.Seq,
		Segments:       segments,
		ReplyToID:      message.ReplyToID,
		Status:         string(message.Status),
		Category:       string(message.Category),
		CreatedAt:      FormatTime(message.CreatedAt),
	}
}

// ConvertConversationToResponse 将Conversation转换为ConversationResponse
// participants: 会话参与者列表（用户信息）
// unreadCount: 当前用户的未读消息数
// lastMessage: 最后一条消息
func ConvertConversationToResponse(conv *model.Conversation, participants []*model.User, unreadCount int, lastMessage *model.Message, isPinned bool) *ConversationResponse {
	if conv == nil {
		return nil
	}

	var participantResponses []*UserResponse
	for _, p := range participants {
		participantResponses = append(participantResponses, ConvertUserToResponse(p))
	}

	// 转换群组信息
	var groupResponse *GroupResponse
	if conv.Group != nil {
		groupResponse = GroupToResponse(conv.Group)
	}

	return &ConversationResponse{
		ID:            conv.ID,
		Type:          string(conv.Type),
		IsPinned:      isPinned,
		Group:         groupResponse,
		LastSeq:       conv.LastSeq,
		LastMessage:   ConvertMessageToResponse(lastMessage),
		LastMessageAt: FormatTimePointer(conv.LastMsgTime),
		UnreadCount:   unreadCount,
		Participants:  participantResponses,
		CreatedAt:     FormatTime(conv.CreatedAt),
		UpdatedAt:     FormatTime(conv.UpdatedAt),
	}
}

// ConvertConversationToDetailResponse 将Conversation转换为ConversationDetailResponse
func ConvertConversationToDetailResponse(conv *model.Conversation, participants []*model.User, unreadCount int64, lastMessage *model.Message, myLastReadSeq int64, otherLastReadSeq int64, isPinned bool) *ConversationDetailResponse {
	if conv == nil {
		return nil
	}

	var participantResponses []*UserResponse
	for _, p := range participants {
		participantResponses = append(participantResponses, ConvertUserToResponse(p))
	}

	return &ConversationDetailResponse{
		ID:               conv.ID,
		Type:             string(conv.Type),
		IsPinned:         isPinned,
		LastSeq:          conv.LastSeq,
		LastMessage:      ConvertMessageToResponse(lastMessage),
		LastMessageAt:    FormatTimePointer(conv.LastMsgTime),
		UnreadCount:      unreadCount,
		Participants:     participantResponses,
		MyLastReadSeq:    myLastReadSeq,
		OtherLastReadSeq: otherLastReadSeq,
		CreatedAt:        FormatTime(conv.CreatedAt),
		UpdatedAt:        FormatTime(conv.UpdatedAt),
	}
}

// ConvertMessagesToResponse 将Message列表转换为响应列表
func ConvertMessagesToResponse(messages []*model.Message) []*MessageResponse {
	result := make([]*MessageResponse, 0, len(messages))
	for _, msg := range messages {
		result = append(result, ConvertMessageToResponse(msg))
	}
	return result
}

// ConvertConversationsToResponse 将Conversation列表转换为响应列表
func ConvertConversationsToResponse(convs []*model.Conversation) []*ConversationResponse {
	result := make([]*ConversationResponse, 0, len(convs))
	for _, conv := range convs {
		result = append(result, ConvertConversationToResponse(conv, nil, 0, nil, false))
	}
	return result
}

// ==================== PushRecord 转换 ====================

// PushRecordToResponse 将PushRecord转换为PushRecordResponse
func PushRecordToResponse(record *model.PushRecord) *PushRecordResponse {
	if record == nil {
		return nil
	}
	resp := &PushRecordResponse{
		ID:          record.ID,
		MessageID:   record.MessageID,
		PushChannel: string(record.PushChannel),
		PushStatus:  string(record.PushStatus),
		RetryCount:  record.RetryCount,
		CreatedAt:   record.CreatedAt,
	}
	if record.PushedAt != nil {
		resp.PushedAt = *record.PushedAt
	}
	if record.DeliveredAt != nil {
		resp.DeliveredAt = *record.DeliveredAt
	}
	return resp
}

// PushRecordsToResponse 将PushRecord列表转换为响应列表
func PushRecordsToResponse(records []*model.PushRecord) []*PushRecordResponse {
	result := make([]*PushRecordResponse, 0, len(records))
	for _, record := range records {
		result = append(result, PushRecordToResponse(record))
	}
	return result
}

// ==================== DeviceToken 转换 ====================

// DeviceTokenToResponse 将DeviceToken转换为DeviceTokenResponse
func DeviceTokenToResponse(token *model.DeviceToken) *DeviceTokenResponse {
	if token == nil {
		return nil
	}
	resp := &DeviceTokenResponse{
		ID:         token.ID,
		DeviceID:   token.DeviceID,
		DeviceType: string(token.DeviceType),
		IsActive:   token.IsActive,
		DeviceName: token.DeviceName,
		CreatedAt:  token.CreatedAt,
	}
	if token.LastUsedAt != nil {
		resp.LastUsedAt = *token.LastUsedAt
	}
	return resp
}

// DeviceTokensToResponse 将DeviceToken列表转换为响应列表
func DeviceTokensToResponse(tokens []*model.DeviceToken) []*DeviceTokenResponse {
	result := make([]*DeviceTokenResponse, 0, len(tokens))
	for _, token := range tokens {
		result = append(result, DeviceTokenToResponse(token))
	}
	return result
}

// ==================== SystemMessage 转换 ====================

// SystemMessageToResponse 将Message转换为SystemMessageResponse
func SystemMessageToResponse(msg *model.Message) *SystemMessageResponse {
	if msg == nil {
		return nil
	}

	// 从 segments 中提取文本内容
	content := ExtractTextContentFromModel(msg.Segments)

	resp := &SystemMessageResponse{
		ID:         msg.ID,
		SenderID:   msg.SenderID,
		ReceiverID: "", // 系统消息的接收者需要从上下文获取
		Content:    content,
		Category:   string(msg.Category),
		SystemType: string(msg.SystemType),
		CreatedAt:  msg.CreatedAt,
	}
	if msg.ExtraData != nil {
		resp.ExtraData = map[string]interface{}{
			"actor_id":    msg.ExtraData.ActorID,
			"actor_name":  msg.ExtraData.ActorName,
			"avatar_url":  msg.ExtraData.AvatarURL,
			"target_id":   msg.ExtraData.TargetID,
			"target_type": msg.ExtraData.TargetType,
			"action_url":  msg.ExtraData.ActionURL,
			"action_time": msg.ExtraData.ActionTime,
		}
	}
	return resp
}

// SystemMessagesToResponse 将Message列表转换为SystemMessageResponse列表
func SystemMessagesToResponse(messages []*model.Message) []*SystemMessageResponse {
	result := make([]*SystemMessageResponse, 0, len(messages))
	for _, msg := range messages {
		result = append(result, SystemMessageToResponse(msg))
	}
	return result
}

// SystemNotificationToResponse 将SystemNotification转换为SystemMessageResponse
func SystemNotificationToResponse(n *model.SystemNotification) *SystemMessageResponse {
	if n == nil {
		return nil
	}
	resp := &SystemMessageResponse{
		ID:         strconv.FormatInt(n.ID, 10),
		SenderID:   model.SystemSenderIDStr, // 系统发送者
		ReceiverID: n.ReceiverID,
		Content:    n.Content,
		Category:   "notification",
		SystemType: string(n.Type),
		IsRead:     n.IsRead,
		CreatedAt:  n.CreatedAt,
	}
	if n.ExtraData != nil {
		resp.ExtraData = map[string]interface{}{
			"actor_id":           n.ExtraData.ActorID,
			"actor_id_str":       n.ExtraData.ActorIDStr,
			"actor_name":         n.ExtraData.ActorName,
			"avatar_url":         n.ExtraData.AvatarURL,
			"target_id":          n.ExtraData.TargetID,
			"target_title":       n.ExtraData.TargetTitle,
			"target_type":        n.ExtraData.TargetType,
			"action_url":         n.ExtraData.ActionURL,
			"action_time":        n.ExtraData.ActionTime,
			"group_id":           n.ExtraData.GroupID,
			"group_name":         n.ExtraData.GroupName,
			"group_avatar":       n.ExtraData.GroupAvatar,
			"group_description":  n.ExtraData.GroupDescription,
			"flag":               n.ExtraData.Flag,
			"request_type":       n.ExtraData.RequestType,
			"request_status":     n.ExtraData.RequestStatus,
			"reason":             n.ExtraData.Reason,
			"target_user_id":     n.ExtraData.TargetUserID,
			"target_user_name":   n.ExtraData.TargetUserName,
			"target_user_avatar": n.ExtraData.TargetUserAvatar,
		}
	}
	return resp
}

// SystemNotificationsToResponse 将SystemNotification列表转换为SystemMessageResponse列表
func SystemNotificationsToResponse(notifications []*model.SystemNotification) []*SystemMessageResponse {
	result := make([]*SystemMessageResponse, 0, len(notifications))
	for _, n := range notifications {
		result = append(result, SystemNotificationToResponse(n))
	}
	return result
}

// ==================== Group 转换 ====================

// GroupToResponse 将Group转换为GroupResponse
func GroupToResponse(group *model.Group) *GroupResponse {
	if group == nil {
		return nil
	}
	return &GroupResponse{
		ID:          group.ID,
		Name:        group.Name,
		Avatar:      group.Avatar,
		Description: group.Description,
		OwnerID:     group.OwnerID,
		MemberCount: group.MemberCount,
		MaxMembers:  group.MaxMembers,
		JoinType:    int(group.JoinType),
		MuteAll:     group.MuteAll,
		CreatedAt:   FormatTime(group.CreatedAt),
	}
}

// GroupsToResponse 将Group列表转换为GroupResponse列表
func GroupsToResponse(groups []model.Group) []*GroupResponse {
	result := make([]*GroupResponse, 0, len(groups))
	for i := range groups {
		result = append(result, GroupToResponse(&groups[i]))
	}
	return result
}

// GroupMemberToResponse 将GroupMember转换为GroupMemberResponse
func GroupMemberToResponse(member *model.GroupMember) *GroupMemberResponse {
	if member == nil {
		return nil
	}
	return &GroupMemberResponse{
		ID:       member.ID,
		GroupID:  member.GroupID,
		UserID:   member.UserID,
		Role:     member.Role,
		Nickname: member.Nickname,
		Muted:    member.Muted,
		JoinTime: FormatTime(member.JoinTime),
	}
}

// GroupMemberToResponseWithUser 将GroupMember转换为GroupMemberResponse（包含用户信息）
func GroupMemberToResponseWithUser(member *model.GroupMember, user *model.User) *GroupMemberResponse {
	if member == nil {
		return nil
	}
	resp := GroupMemberToResponse(member)
	if user != nil {
		resp.User = ConvertUserToResponse(user)
	}
	return resp
}

// GroupMembersToResponse 将GroupMember列表转换为GroupMemberResponse列表
func GroupMembersToResponse(members []model.GroupMember) []*GroupMemberResponse {
	result := make([]*GroupMemberResponse, 0, len(members))
	for i := range members {
		result = append(result, GroupMemberToResponse(&members[i]))
	}
	return result
}

// GroupAnnouncementToResponse 将GroupAnnouncement转换为GroupAnnouncementResponse
func GroupAnnouncementToResponse(announcement *model.GroupAnnouncement) *GroupAnnouncementResponse {
	if announcement == nil {
		return nil
	}
	return &GroupAnnouncementResponse{
		ID:        announcement.ID,
		GroupID:   announcement.GroupID,
		Content:   announcement.Content,
		AuthorID:  announcement.AuthorID,
		IsPinned:  announcement.IsPinned,
		CreatedAt: FormatTime(announcement.CreatedAt),
	}
}

// GroupAnnouncementsToResponse 将GroupAnnouncement列表转换为GroupAnnouncementResponse列表
func GroupAnnouncementsToResponse(announcements []model.GroupAnnouncement) []*GroupAnnouncementResponse {
	result := make([]*GroupAnnouncementResponse, 0, len(announcements))
	for i := range announcements {
		result = append(result, GroupAnnouncementToResponse(&announcements[i]))
	}
	return result
}