perf(chat): 优化后台客服会话查询与状态

backend/internal/modules/chat/participant.go

@@ -25,6 +25,7 @@ type conversationRow struct {
 	Title               string
 	Status              string
 	Role                string
+	AdminRemark         string
 	LastMessageID       *uint64
 	LastMessagePreview  string
 	LastMessageAt       *time.Time
@@ -44,6 +45,7 @@ func (r *Repository) conversationQuery(ctx context.Context, principal Principal)
 				SELECT COUNT(1)
 				FROM chat_messages AS cm
 				WHERE cm.conversation_id = c.id
+				  AND cm.sender_type <> 'system'
 				  AND NOT (cm.sender_type = ? AND cm.sender_id = ?)
 				  AND (cp.last_read_at IS NULL OR cm.created_at > cp.last_read_at)
 			) AS unread_count`, principal.Type, principal.ID).
@@ -59,6 +61,7 @@ func (r *Repository) CountUnreadMessages(ctx context.Context, principal Principa
 		Where("cp.participant_type = ? AND cp.participant_id = ?", principal.Type, principal.ID).
 		Where("c.status = ?", "active").
 		Where("NOT (cm.sender_type = ? AND cm.sender_id = ?)", principal.Type, principal.ID).
+		Where("cm.sender_type <> ?", "system").
 		Where("(cp.last_read_at IS NULL OR cm.created_at > cp.last_read_at)").
 		Count(&total).Error
 	return total, err
@@ -81,15 +84,29 @@ func (r *Repository) findParticipant(tx *gorm.DB, principal Principal, conversat
 	return &participant, nil
 }
 func (r *Repository) participants(ctx context.Context, conversationID uint64) ([]ParticipantDTO, error) {
+	grouped, err := r.participantsForConversations(ctx, []uint64{conversationID})
+	if err != nil {
+		return nil, err
+	}
+	return grouped[conversationID], nil
+}
+
+func (r *Repository) participantsForConversations(ctx context.Context, conversationIDs []uint64) (map[uint64][]ParticipantDTO, error) {
+	result := make(map[uint64][]ParticipantDTO, len(conversationIDs))
+	if len(conversationIDs) == 0 {
+		return result, nil
+	}
 	var rows []model.ChatParticipant
-	if err := r.db.WithContext(ctx).Where("conversation_id = ?", conversationID).Order("id ASC").Find(&rows).Error; err != nil {
+	if err := r.db.WithContext(ctx).
+		Where("conversation_id IN ?", uniqueIDs(conversationIDs)).
+		Order("conversation_id ASC, id ASC").
+		Find(&rows).Error; err != nil {
 		return nil, err
 	}
 	userNames, userAvatars, adminNames, err := r.participantNames(ctx, rows)
 	if err != nil {
 		return nil, err
 	}
-	items := make([]ParticipantDTO, 0, len(rows))
 	for _, row := range rows {
 		name := "系统"
 		avatar := ""
@@ -100,19 +117,20 @@ func (r *Repository) participants(ctx context.Context, conversationID uint64) ([
 		if row.ParticipantType == "admin" {
 			name = adminNames[row.ParticipantID]
 		}
-		items = append(items, ParticipantDTO{
+		result[row.ConversationID] = append(result[row.ConversationID], ParticipantDTO{
 			ID:              row.ID,
 			ConversationID:  row.ConversationID,
 			ParticipantType: row.ParticipantType,
 			ParticipantID:   row.ParticipantID,
 			Role:            row.Role,
+			Remark:          row.Remark,
 			DisplayName:     fallbackName(row.ParticipantType, row.ParticipantID, name),
 			AvatarURL:       avatar,
 			LastReadAt:      row.LastReadAt,
 			JoinedAt:        row.JoinedAt,
 		})
 	}
-	return items, nil
+	return result, nil
 }
 func (r *Repository) toMessageDTOs(ctx context.Context, principal Principal, rows []model.ChatMessage) ([]MessageDTO, error) {
 	userIDs := make([]uint64, 0)
@@ -305,6 +323,7 @@ func (row conversationRow) toDTO(participants []ParticipantDTO) ConversationDTO
 		Title:               row.Title,
 		Status:              row.Status,
 		Role:                row.Role,
+		AdminRemark:         row.AdminRemark,
 		Participants:        participants,
 		LastMessageID:       row.LastMessageID,
 		LastMessagePreview:  row.LastMessagePreview,