优化了消息数量,筛选和顶部部分

backend/internal/modules/chat/dto.go

@@ -51,6 +51,10 @@ type MessageDTO struct {
 	CreatedAt      time.Time `json:"created_at"`
 }
 
+type UnreadCountDTO struct {
+	UnreadCount int64 `json:"unread_count"`
+}
+
 type SendMessageRequest struct {
 	Content        string   `json:"content"`
 	AttachmentURLS []string `json:"attachment_urls"`

backend/internal/modules/chat/handler_user.go

@@ -15,6 +15,20 @@ func (h *Handler) List(c *gin.Context) {
 	h.list(c, Principal{Type: "user", ID: userID})
 }
 
+func (h *Handler) UnreadCount(c *gin.Context) {
+	userID, ok := currentUserID(c)
+	if !ok {
+		response.Unauthorized(c, "缺少用户上下文")
+		return
+	}
+	result, err := h.service.CountUnreadMessages(c.Request.Context(), Principal{Type: "user", ID: userID})
+	if err != nil {
+		writeChatError(c, err)
+		return
+	}
+	response.OK(c, result)
+}
+
 func (h *Handler) Detail(c *gin.Context) {
 	userID, ok := currentUserID(c)
 	if !ok {

backend/internal/modules/chat/participant.go

@@ -40,6 +40,18 @@ func (r *Repository) conversationQuery(ctx context.Context, principal Principal)
 		Joins("JOIN chat_participants AS cp ON cp.conversation_id = c.id").
 		Where("cp.participant_type = ? AND cp.participant_id = ?", principal.Type, principal.ID)
 }
+
+func (r *Repository) CountUnreadMessages(ctx context.Context, principal Principal) (int64, error) {
+	var total int64
+	err := r.db.WithContext(ctx).Table("chat_messages AS cm").
+		Joins("JOIN chat_participants AS cp ON cp.conversation_id = cm.conversation_id").
+		Where("cp.participant_type = ? AND cp.participant_id = ?", principal.Type, principal.ID).
+		Where("NOT (cm.sender_type = ? AND cm.sender_id = ?)", principal.Type, principal.ID).
+		Where("(cp.last_read_at IS NULL OR cm.created_at > cp.last_read_at)").
+		Count(&total).Error
+	return total, err
+}
+
 func (r *Repository) findParticipant(tx *gorm.DB, principal Principal, conversationID uint64, lock bool) (*model.ChatParticipant, error) {
 	var participant model.ChatParticipant
 	db := tx

backend/internal/modules/chat/service.go

@@ -29,6 +29,17 @@ func (s *Service) ListConversations(ctx context.Context, principal Principal, pa
 	return s.repo.ListConversations(ctx, principal, page, pageSize)
 }
 
+func (s *Service) CountUnreadMessages(ctx context.Context, principal Principal) (*UnreadCountDTO, error) {
+	if s.repo == nil {
+		return nil, ErrDependencyUnavailable
+	}
+	total, err := s.repo.CountUnreadMessages(ctx, principal)
+	if err != nil {
+		return nil, err
+	}
+	return &UnreadCountDTO{UnreadCount: total}, nil
+}
+
 func (s *Service) FindConversation(ctx context.Context, principal Principal, id uint64) (*ConversationDTO, error) {
 	if s.repo == nil {
 		return nil, ErrDependencyUnavailable

backend/internal/router/router.go

@@ -403,6 +403,7 @@ func New(cfg config.Config, deps Dependencies, logger *zap.Logger) *gin.Engine {
 				chatRoutes.GET("/events", chatHubHandler.UserEvents)
 			}
 			chatRoutes.POST("/support", chatHandler.EnsureSupportConversation)
+			chatRoutes.GET("/unread-count", chatHandler.UnreadCount)
 			chatRoutes.GET("", chatHandler.List)
 			chatRoutes.GET("/:id", chatHandler.Detail)
 			chatRoutes.GET("/:id/messages", chatHandler.Messages)