perf(chat): 优化后台客服会话查询与状态

backend/internal/database/test_helper.go

@@ -63,6 +63,7 @@ func MigrateRentalTransactionTestSchema(db *gorm.DB) error {
 		&model.AuditLog{},
 		&model.ChatConversation{},
 		&model.ChatParticipant{},
+		&model.ChatAdminConversationState{},
 		&model.ChatMessage{},
 	)
 }

backend/internal/model/chat.go

@@ -42,6 +42,23 @@ func (ChatParticipant) TableName() string {
 	return "chat_participants"
 }
 
+// ChatAdminConversationState stores per-admin state even when the admin is not
+// an assigned participant of the conversation.
+type ChatAdminConversationState struct {
+	ID                uint64     `gorm:"primaryKey" json:"id"`
+	ConversationID    uint64     `gorm:"not null;uniqueIndex:uk_chat_admin_conversation_state;index" json:"conversation_id"`
+	AdminUserID       uint64     `gorm:"not null;uniqueIndex:uk_chat_admin_conversation_state;index" json:"admin_user_id"`
+	Remark            string     `gorm:"size:128;not null;default:''" json:"remark"`
+	LastReadMessageID uint64     `gorm:"not null;default:0" json:"last_read_message_id"`
+	LastReadAt        *time.Time `json:"last_read_at"`
+	CreatedAt         time.Time  `json:"created_at"`
+	UpdatedAt         time.Time  `json:"updated_at"`
+}
+
+func (ChatAdminConversationState) TableName() string {
+	return "chat_admin_conversation_states"
+}
+
 type ChatMessage struct {
 	ID             uint64         `gorm:"primaryKey" json:"id"`
 	ConversationID uint64         `gorm:"not null;index" json:"conversation_id"`

backend/internal/modules/chat/admin_list_test.go

@@ -0,0 +1,106 @@
+package chat
+
+import (
+	"testing"
+	"time"
+
+	"hfb_sys/backend/internal/model"
+
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+)
+
+func setupAdminListTestDB(t *testing.T) *gorm.DB {
+	t.Helper()
+	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{Logger: logger.Default.LogMode(logger.Silent)})
+	if err != nil {
+		t.Fatalf("打开测试数据库失败: %v", err)
+	}
+	if err := db.AutoMigrate(
+		&model.User{},
+		&model.AdminUser{},
+		&model.RentalListing{},
+		&model.RentalOrder{},
+		&model.ChatConversation{},
+		&model.ChatParticipant{},
+		&model.ChatAdminConversationState{},
+		&model.ChatMessage{},
+	); err != nil {
+		t.Fatalf("迁移测试数据库失败: %v", err)
+	}
+	return db
+}
+
+func TestListAdminConversationsUsesPersonalStateAndBatchData(t *testing.T) {
+	db := setupAdminListTestDB(t)
+	repo := NewRepository(db, nil, nil)
+
+	admin := model.AdminUser{Username: "cs-1", Nickname: "客服一", Status: "active"}
+	user := model.User{Phone: "13800000001", Nickname: "租客"}
+	if err := db.Create(&admin).Error; err != nil {
+		t.Fatalf("创建管理员失败: %v", err)
+	}
+	if err := db.Create(&user).Error; err != nil {
+		t.Fatalf("创建用户失败: %v", err)
+	}
+	listing := model.RentalListing{ListingNo: "L202608250001", OwnerID: user.ID, AccountID: 1, Status: "active"}
+	if err := db.Create(&listing).Error; err != nil {
+		t.Fatalf("创建商品失败: %v", err)
+	}
+	order := model.RentalOrder{OrderNo: "RO-CHAT-1", ListingID: listing.ID, AccountID: 1, OwnerID: user.ID, RenterID: user.ID, Status: "renting"}
+	if err := db.Create(&order).Error; err != nil {
+		t.Fatalf("创建订单失败: %v", err)
+	}
+	conversation := model.ChatConversation{OrderID: &order.ID, Type: ConversationTypeOrderGroup, Title: "订单群", Status: "active"}
+	if err := db.Create(&conversation).Error; err != nil {
+		t.Fatalf("创建会话失败: %v", err)
+	}
+	now := time.Now()
+	if err := db.Create(&[]model.ChatParticipant{
+		{ConversationID: conversation.ID, ParticipantType: "user", ParticipantID: user.ID, Role: "renter", JoinedAt: now},
+		{ConversationID: conversation.ID, ParticipantType: "admin", ParticipantID: admin.ID, Role: "support", JoinedAt: now},
+	}).Error; err != nil {
+		t.Fatalf("创建参与人失败: %v", err)
+	}
+	system := model.ChatMessage{ConversationID: conversation.ID, SenderType: "system", SenderRole: "system", ContentType: "system", Content: "欢迎", CreatedAt: now}
+	userMessage := model.ChatMessage{ConversationID: conversation.ID, SenderType: "user", SenderID: user.ID, SenderRole: "renter", ContentType: "text", Content: "请问？", CreatedAt: now.Add(time.Second)}
+	if err := db.Create(&[]model.ChatMessage{system, userMessage}).Error; err != nil {
+		t.Fatalf("创建消息失败: %v", err)
+	}
+	if err := db.Model(&conversation).Updates(map[string]interface{}{
+		"last_message_id":      userMessage.ID,
+		"last_message_preview": userMessage.Content,
+		"last_message_at":      userMessage.CreatedAt,
+	}).Error; err != nil {
+		t.Fatalf("更新会话摘要失败: %v", err)
+	}
+	if err := db.Create(&model.ChatAdminConversationState{
+		ConversationID:    conversation.ID,
+		AdminUserID:       admin.ID,
+		Remark:            "客户一",
+		LastReadMessageID: system.ID,
+		LastReadAt:        &system.CreatedAt,
+	}).Error; err != nil {
+		t.Fatalf("创建管理员状态失败: %v", err)
+	}
+
+	result, err := repo.ListConversationsWithFilter(t.Context(), Principal{Type: "admin", ID: admin.ID}, 1, 20, adminChatFilterMine, adminChatStageAll, "")
+	if err != nil {
+		t.Fatalf("查询后台会话失败: %v", err)
+	}
+	if result.Total != 1 || len(result.Items.([]ConversationDTO)) != 1 {
+		t.Fatalf("会话数量 = total %d/items %d, want 1/1", result.Total, len(result.Items.([]ConversationDTO)))
+	}
+	item := result.Items.([]ConversationDTO)[0]
+	if item.AdminRemark != "客户一" {
+		t.Fatalf("管理员备注 = %q, want 客户一", item.AdminRemark)
+	}
+	if item.UnreadCount != 1 {
+		t.Fatalf("管理员未读数 = %d, want 1", item.UnreadCount)
+	}
+	counts := result.Counts.(*AdminConversationCountsDTO)
+	if counts.Ownership[adminChatFilterMine] != 1 || counts.Stages[adminChatStageAll] != 1 {
+		t.Fatalf("聚合统计异常: ownership=%v stages=%v", counts.Ownership, counts.Stages)
+	}
+}

backend/internal/modules/chat/conversation.go

@@ -53,6 +53,19 @@ func (r *Repository) FindConversation(ctx context.Context, principal Principal,
 		if err != nil {
 			return nil, err
 		}
+		var state model.ChatAdminConversationState
+		if err := db.Where("conversation_id = ? AND admin_user_id = ?", conversation.ID, principal.ID).First(&state).Error; err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, err
+		}
+		var unreadCount int64
+		if err := db.Table("chat_messages AS cm").
+			Where("cm.conversation_id = ?", conversation.ID).
+			Where("cm.sender_type <> ?", "system").
+			Where("NOT (cm.sender_type = ? AND cm.sender_id = ?)", "admin", principal.ID).
+			Where("cm.id > ?", state.LastReadMessageID).
+			Count(&unreadCount).Error; err != nil {
+			return nil, err
+		}
 		dto := ConversationDTO{
 			ID:                 conversation.ID,
 			OrderID:            conversation.OrderID,
@@ -62,11 +75,12 @@ func (r *Repository) FindConversation(ctx context.Context, principal Principal,
 			Title:              conversation.Title,
 			Status:             conversation.Status,
 			Role:               "admin", // 管理员角色
+			AdminRemark:        state.Remark,
 			Participants:       participants,
 			LastMessageID:      conversation.LastMessageID,
 			LastMessagePreview: conversation.LastMessagePreview,
 			LastMessageAt:      conversation.LastMessageAt,
-			UnreadCount:        0, // 管理员不计未读
+			UnreadCount:        unreadCount,
 			CreatedAt:          conversation.CreatedAt,
 			UpdatedAt:          conversation.UpdatedAt,
 		}

backend/internal/modules/chat/conversation_test.go

@@ -24,6 +24,7 @@ func setupConversationTestDB(t *testing.T) *gorm.DB {
 		&model.RentalOrder{},
 		&model.ChatConversation{},
 		&model.ChatParticipant{},
+		&model.ChatAdminConversationState{},
 		&model.ChatMessage{},
 	); err != nil {
 		t.Fatalf("数据库迁移失败: %v", err)

backend/internal/modules/chat/dto.go

@@ -21,6 +21,7 @@ type ConversationDTO struct {
 	Title               string           `json:"title"`
 	Status              string           `json:"status"`
 	Role                string           `json:"role"`
+	AdminRemark         string           `json:"admin_remark,omitempty"`
 	Participants        []ParticipantDTO `json:"participants,omitempty"`
 	LastMessageID       *uint64          `json:"last_message_id"`
 	LastMessagePreview  string           `json:"last_message_preview"`

backend/internal/modules/chat/message.go

@@ -40,12 +40,15 @@ func (r *Repository) Messages(ctx context.Context, principal Principal, conversa
 
 	offset := (page - 1) * pageSize
 	var rows []model.ChatMessage
-	if err := query.Order("id ASC").
+	if err := query.Order("id DESC").
 		Offset(offset).
 		Limit(pageSize).
 		Find(&rows).Error; err != nil {
 		return nil, err
 	}
+	for left, right := 0, len(rows)-1; left < right; left, right = left+1, right-1 {
+		rows[left], rows[right] = rows[right], rows[left]
+	}
 	items, err := r.toMessageDTOs(ctx, principal, rows)
 	if err != nil {
 		return nil, err
@@ -166,21 +169,44 @@ func (r *Repository) MarkRead(ctx context.Context, principal Principal, conversa
 	now := time.Now()
 	updated := false
 	err := r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
-		// 管理员可以不是 participant，直接返回成功
 		if principal.Type == "admin" {
-			// 尝试查找 participant 记录，如果有就更新
-			var participant model.ChatParticipant
-			err := tx.Where("conversation_id = ? AND participant_type = ? AND participant_id = ?",
-				conversationID, principal.Type, principal.ID).First(&participant).Error
-			if err == nil {
-				// 有 participant 记录，更新已读时间
-				updated = true
-				return tx.Model(&participant).Update("last_read_at", now).Error
-			} else if errors.Is(err, gorm.ErrRecordNotFound) {
-				// 没有 participant 记录，直接返回成功（管理员无需记录已读）
+			var conversation model.ChatConversation
+			if err := tx.Select("id", "last_message_id").First(&conversation, conversationID).Error; err != nil {
+				if errors.Is(err, gorm.ErrRecordNotFound) {
+					return ErrConversationNotFound
+				}
+				return err
+			}
+			lastMessageID := uint64(0)
+			if conversation.LastMessageID != nil {
+				lastMessageID = *conversation.LastMessageID
+			}
+			var existing model.ChatAdminConversationState
+			err := tx.Where("conversation_id = ? AND admin_user_id = ?", conversationID, principal.ID).
+				First(&existing).Error
+			if err == nil && existing.LastReadMessageID >= lastMessageID {
 				return nil
 			}
-			return err
+			if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
+				return err
+			}
+			state := model.ChatAdminConversationState{
+				ConversationID:    conversationID,
+				AdminUserID:       principal.ID,
+				LastReadMessageID: lastMessageID,
+				LastReadAt:        &now,
+			}
+			if err := tx.Clauses(clause.OnConflict{
+				Columns: []clause.Column{{Name: "conversation_id"}, {Name: "admin_user_id"}},
+				DoUpdates: clause.Assignments(map[string]interface{}{
+					"last_read_message_id": lastMessageID,
+					"last_read_at":         now,
+				}),
+			}).Create(&state).Error; err != nil {
+				return err
+			}
+			updated = true
+			return nil
 		}
 
 		// 普通用户必须是 participant

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,

backend/internal/modules/chat/quick_reply.go

@@ -2,7 +2,12 @@ package chat
 
 import (
 	"context"
+	"errors"
 	"hfb_sys/backend/internal/model"
+	"strings"
+
+	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
 )
 
 const (
@@ -13,9 +18,26 @@ const (
 )
 
 func (r *Repository) UpdateRemark(ctx context.Context, principal Principal, conversationID uint64, remark string) error {
-	return r.db.WithContext(ctx).Model(&model.ChatParticipant{}).
-		Where("conversation_id = ? AND participant_type = ? AND participant_id = ?", conversationID, principal.Type, principal.ID).
-		Update("remark", remark).Error
+	if principal.Type != "admin" {
+		return ErrPermissionDenied
+	}
+	db := r.db.WithContext(ctx)
+	var conversation model.ChatConversation
+	if err := db.Select("id").First(&conversation, conversationID).Error; err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return ErrConversationNotFound
+		}
+		return err
+	}
+	state := model.ChatAdminConversationState{
+		ConversationID: conversationID,
+		AdminUserID:    principal.ID,
+		Remark:         strings.TrimSpace(remark),
+	}
+	return db.Clauses(clause.OnConflict{
+		Columns:   []clause.Column{{Name: "conversation_id"}, {Name: "admin_user_id"}},
+		DoUpdates: clause.AssignmentColumns([]string{"remark", "updated_at"}),
+	}).Create(&state).Error
 }
 func (r *Repository) ListQuickReplies(ctx context.Context, adminID uint64) ([]QuickReplyDTO, error) {
 	var replies []model.ChatQuickReply

backend/internal/modules/chat/service.go

@@ -159,6 +159,10 @@ func (s *Service) UpdateRemark(ctx context.Context, principal Principal, convers
 	if s.repo == nil {
 		return ErrDependencyUnavailable
 	}
+	req.Remark = strings.TrimSpace(req.Remark)
+	if len([]rune(req.Remark)) > 128 {
+		return ErrInvalidMessage
+	}
 	return s.repo.UpdateRemark(ctx, principal, conversationID, req.Remark)
 }
 

backend/internal/modules/chat/support.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"gorm.io/gorm"
 	"hfb_sys/backend/internal/model"
+	"hfb_sys/backend/internal/modules/chathub"
 	"strings"
 	"time"
 )
@@ -33,15 +34,17 @@ type AdminConversationCountsDTO struct {
 }
 
 func (r *Repository) TransferConversation(ctx context.Context, principal Principal, conversationID uint64, toAdminID uint64) error {
-	return r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
-		// 验证当前操作者是会话参与者
-		current, err := r.findParticipant(tx, principal, conversationID, false)
-		if err != nil {
-			return err
-		}
-		if current.Role != "support" || current.ParticipantType != "admin" {
+	err := r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+		if principal.Type != "admin" {
 			return ErrPermissionDenied
 		}
+		var conversation model.ChatConversation
+		if err := tx.First(&conversation, conversationID).Error; err != nil {
+			if errors.Is(err, gorm.ErrRecordNotFound) {
+				return ErrConversationNotFound
+			}
+			return err
+		}
 		// 验证目标客服存在、活跃且拥有客服角色，避免转接给超级管理员。
 		if !adminIsSupport(tx, toAdminID) {
 			return fmt.Errorf("目标客服不存在、已禁用或不是客服角色")
@@ -56,29 +59,45 @@ func (r *Repository) TransferConversation(ctx context.Context, principal Princip
 		if count > 0 {
 			return fmt.Errorf("该客服已在会话中")
 		}
-		// 只转接当前客服本人，避免误删同群里的收号组/卖号组其他客服。
-		if err := tx.Model(&model.ChatParticipant{}).
-			Where("id = ?", current.ID).
-			Updates(map[string]interface{}{
+		var current model.ChatParticipant
+		currentErr := tx.Where("conversation_id = ? AND participant_type = ? AND participant_id = ?", conversationID, "admin", principal.ID).
+			First(&current).Error
+		if currentErr == nil {
+			if current.Role != "support" {
+				return ErrPermissionDenied
+			}
+			// 只转接当前客服本人，避免误删同群里的其他客服。
+			if err := tx.Model(&current).Updates(map[string]interface{}{
 				"participant_id": toAdminID,
 				"joined_at":      time.Now(),
+				"last_read_at":   nil,
 			}).Error; err != nil {
-			return err
+				return err
+			}
+		} else if errors.Is(currentErr, gorm.ErrRecordNotFound) {
+			// 未分配会话允许从“全部/未分配”直接指派给目标客服。
+			if err := tx.Create(&model.ChatParticipant{
+				ConversationID:  conversationID,
+				ParticipantType: "admin",
+				ParticipantID:   toAdminID,
+				Role:            "support",
+				JoinedAt:        time.Now(),
+			}).Error; err != nil {
+				return err
+			}
+		} else {
+			return currentErr
 		}
-		// 添加系统消息记录转接
-		message := model.ChatMessage{
-			ConversationID: conversationID,
-			SenderType:     "system",
-			SenderRole:     "system",
-			ContentType:    "system",
-			Content:        "会话已转接给其他客服",
-			AttachmentURLS: emptyJSONList(),
-		}
-		if err := tx.Create(&message).Error; err != nil {
+		if err := sendSystemMessage(tx, conversationID, "会话已转接给其他客服"); err != nil {
 			return err
 		}
 		return nil
 	})
+	if err == nil && r.hub != nil {
+		r.hub.NotifyConversation(conversationID, &chathub.ChatEvent{Type: "conversation_updated", ConversationID: conversationID})
+		r.hub.NotifyAllAdmins(&chathub.ChatEvent{Type: "conversation_updated", ConversationID: conversationID})
+	}
+	return err
 }
 func (r *Repository) GetAvailableSupportAdmins(ctx context.Context) ([]SupportAdminDTO, error) {
 	db := r.db.WithContext(ctx)
@@ -202,11 +221,8 @@ func (r *Repository) ListConversationsWithFilter(ctx context.Context, principal
 }
 
 func (r *Repository) listAdminConversations(ctx context.Context, principal Principal, page, pageSize int, filter string, stage string, keyword string) (*PaginatedResult, error) {
-	var total int64
-	countDB := r.adminConversationBase(ctx, principal, keyword)
-	applyAdminChatOwnershipFilter(countDB, filter, principal)
-	applyAdminChatStageFilter(countDB, stage, principal)
-	if err := countDB.Count(&total).Error; err != nil {
+	counts, err := r.adminConversationCounts(ctx, principal, filter, stage, keyword)
+	if err != nil {
 		return nil, err
 	}
 
@@ -216,16 +232,21 @@ func (r *Repository) listAdminConversations(ctx context.Context, principal Princ
 		Select(`c.id, c.order_id, c.listing_id, c.type, c.support_scene, c.title, c.status, c.last_message_id,
 			c.last_message_preview, c.last_message_at, c.created_at, c.updated_at,
 			COALESCE(cp_me.role, 'admin') AS role,
-			lo.id AS latest_order_id, lo.order_no AS latest_order_no, lo.status AS latest_order_status,
-			lo.handoff_status AS latest_handoff_status, lo.refund_status AS latest_refund_status,
+			COALESCE(cas.remark, '') AS admin_remark,
+			COALESCE(explicit_lo.id, listing_lo.id) AS latest_order_id,
+			COALESCE(explicit_lo.order_no, listing_lo.order_no) AS latest_order_no,
+			COALESCE(explicit_lo.status, listing_lo.status) AS latest_order_status,
+			COALESCE(explicit_lo.handoff_status, listing_lo.handoff_status) AS latest_handoff_status,
+			COALESCE(explicit_lo.refund_status, listing_lo.refund_status) AS latest_refund_status,
 			lm.sender_type AS last_sender_type, lm.sender_id AS last_sender_id, lm.sender_role AS last_sender_role,
-			CASE WHEN cp_me.id IS NULL THEN 0 ELSE (
+			(
 				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_me.last_read_at IS NULL OR cm.created_at > cp_me.last_read_at)
-			) END AS unread_count`, principal.Type, principal.ID)
+				  AND cm.id > COALESCE(cas.last_read_message_id, 0)
+			) AS unread_count`, principal.Type, principal.ID)
 	applyAdminChatOwnershipFilter(queryDB, filter, principal)
 	applyAdminChatStageFilter(queryDB, stage, principal)
 	if err := queryDB.
@@ -236,33 +257,34 @@ func (r *Repository) listAdminConversations(ctx context.Context, principal Princ
 		return nil, err
 	}
 
-	items := make([]ConversationDTO, 0, len(rows))
+	ids := make([]uint64, 0, len(rows))
 	for _, row := range rows {
-		participants, err := r.participants(ctx, row.ID)
-		if err != nil {
-			return nil, err
-		}
-		items = append(items, row.toDTO(participants))
+		ids = append(ids, row.ID)
 	}
-
-	counts, err := r.adminConversationCounts(ctx, principal, filter, stage, keyword)
+	participantsByConversation, err := r.participantsForConversations(ctx, ids)
 	if err != nil {
 		return nil, err
 	}
-	return &PaginatedResult{Items: items, Total: total, Page: page, PageSize: pageSize, Counts: counts}, nil
+	items := make([]ConversationDTO, 0, len(rows))
+	for _, row := range rows {
+		items = append(items, row.toDTO(participantsByConversation[row.ID]))
+	}
+	return &PaginatedResult{Items: items, Total: counts.Total, Page: page, PageSize: pageSize, Counts: counts.DTO}, nil
 }
 
 func (r *Repository) adminConversationBase(ctx context.Context, principal Principal, keyword string) *gorm.DB {
 	db := r.db.WithContext(ctx).Table("chat_conversations AS c").
 		Joins("LEFT JOIN chat_participants AS cp_me ON cp_me.conversation_id = c.id AND cp_me.participant_type = ? AND cp_me.participant_id = ?", principal.Type, principal.ID).
+		Joins("LEFT JOIN chat_admin_conversation_states AS cas ON cas.conversation_id = c.id AND cas.admin_user_id = ?", principal.ID).
 		Joins("LEFT JOIN chat_messages AS lm ON lm.id = c.last_message_id").
-		Joins("LEFT JOIN rental_orders AS lo ON lo.id = COALESCE(c.order_id, (SELECT ro.id FROM rental_orders AS ro WHERE ro.listing_id = c.listing_id ORDER BY ro.id DESC LIMIT 1))").
-		Joins("LEFT JOIN rental_listings AS l ON l.id = COALESCE(lo.listing_id, c.listing_id)").
-		Joins("LEFT JOIN users AS renter ON renter.id = lo.renter_id").
-		Joins("LEFT JOIN users AS owner ON owner.id = COALESCE(lo.owner_id, l.owner_id)")
+		Joins("LEFT JOIN rental_orders AS explicit_lo ON explicit_lo.id = c.order_id").
+		Joins("LEFT JOIN (SELECT ro.* FROM rental_orders AS ro JOIN (SELECT listing_id, MAX(id) AS max_id FROM rental_orders GROUP BY listing_id) AS latest ON latest.max_id = ro.id) AS listing_lo ON listing_lo.listing_id = c.listing_id AND c.order_id IS NULL").
+		Joins("LEFT JOIN rental_listings AS l ON l.id = COALESCE(explicit_lo.listing_id, listing_lo.listing_id, c.listing_id)")
 	if keyword != "" {
+		db = db.Joins("LEFT JOIN users AS renter ON renter.id = COALESCE(explicit_lo.renter_id, listing_lo.renter_id)").
+			Joins("LEFT JOIN users AS owner ON owner.id = COALESCE(explicit_lo.owner_id, listing_lo.owner_id, l.owner_id)")
 		like := "%" + keyword + "%"
-		db = db.Where(`c.title LIKE ? OR c.last_message_preview LIKE ? OR lo.order_no LIKE ? OR l.listing_no LIKE ?
+		db = db.Where(`c.title LIKE ? OR c.last_message_preview LIKE ? OR COALESCE(explicit_lo.order_no, listing_lo.order_no) LIKE ? OR l.listing_no LIKE ?
 			OR renter.phone LIKE ? OR owner.phone LIKE ?
 			OR EXISTS (
 				SELECT 1 FROM chat_participants AS cp_kw
@@ -272,32 +294,54 @@ func (r *Repository) adminConversationBase(ctx context.Context, principal Princi
 	return db
 }
 
-func (r *Repository) adminConversationCounts(ctx context.Context, principal Principal, filter string, stage string, keyword string) (*AdminConversationCountsDTO, error) {
-	counts := &AdminConversationCountsDTO{
-		Ownership: make(map[string]int64, len(adminChatFilters)),
-		Stages:    make(map[string]int64, len(adminChatStages)),
-	}
+type adminConversationCountsResult struct {
+	Total int64
+	DTO   *AdminConversationCountsDTO
+}
+
+func (r *Repository) adminConversationCounts(ctx context.Context, principal Principal, filter string, stage string, keyword string) (*adminConversationCountsResult, error) {
+	ownership := make(map[string]string, len(adminChatFilters))
+	ownershipArgs := make(map[string][]interface{}, len(adminChatFilters))
 	for _, item := range adminChatFilters {
-		db := r.adminConversationBase(ctx, principal, keyword)
-		applyAdminChatOwnershipFilter(db, item, principal)
-		applyAdminChatStageFilter(db, stage, principal)
-		var count int64
-		if err := db.Count(&count).Error; err != nil {
-			return nil, err
-		}
-		counts.Ownership[item] = count
+		ownership[item], ownershipArgs[item] = adminChatOwnershipCondition(item, principal)
+	}
+	stages := make(map[string]string, len(adminChatStages))
+	stageArgs := make(map[string][]interface{}, len(adminChatStages))
+	for _, item := range adminChatStages {
+		stages[item], stageArgs[item] = adminChatStageCondition(item, principal)
+	}
+
+	parts := make([]string, 0, 1+len(adminChatFilters)+len(adminChatStages))
+	args := make([]interface{}, 0)
+	addCount := func(alias, left, right string, leftArgs, rightArgs []interface{}) {
+		parts = append(parts, "SUM(CASE WHEN "+left+" AND "+right+" THEN 1 ELSE 0 END) AS "+alias)
+		args = append(args, leftArgs...)
+		args = append(args, rightArgs...)
+	}
+	addCount("total", ownership[filter], stages[stage], ownershipArgs[filter], stageArgs[stage])
+	for _, item := range adminChatFilters {
+		addCount("ownership_"+item, ownership[item], stages[stage], ownershipArgs[item], stageArgs[stage])
 	}
 	for _, item := range adminChatStages {
-		db := r.adminConversationBase(ctx, principal, keyword)
-		applyAdminChatOwnershipFilter(db, filter, principal)
-		applyAdminChatStageFilter(db, item, principal)
-		var count int64
-		if err := db.Count(&count).Error; err != nil {
-			return nil, err
-		}
-		counts.Stages[item] = count
+		addCount("stage_"+item, ownership[filter], stages[item], ownershipArgs[filter], stageArgs[item])
 	}
-	return counts, nil
+
+	type row struct {
+		Total                                                                                         int64
+		OwnershipMine, OwnershipAll, OwnershipUnassigned                                              int64
+		StageAll, StagePending, StageUnjoined, StageHandoff, StageRenting, StageAfterSale, StageEnded int64
+	}
+	var result row
+	if err := r.adminConversationBase(ctx, principal, keyword).Select(strings.Join(parts, ", "), args...).Scan(&result).Error; err != nil {
+		return nil, err
+	}
+	return &adminConversationCountsResult{
+		Total: result.Total,
+		DTO: &AdminConversationCountsDTO{
+			Ownership: map[string]int64{adminChatFilterMine: result.OwnershipMine, adminChatFilterAll: result.OwnershipAll, adminChatFilterUnassigned: result.OwnershipUnassigned},
+			Stages:    map[string]int64{adminChatStageAll: result.StageAll, adminChatStagePending: result.StagePending, adminChatStageUnjoined: result.StageUnjoined, adminChatStageHandoff: result.StageHandoff, adminChatStageRenting: result.StageRenting, adminChatStageAfterSale: result.StageAfterSale, adminChatStageEnded: result.StageEnded},
+		},
+	}, nil
 }
 
 func normalizeAdminChatFilter(filter string) string {
@@ -319,52 +363,64 @@ func normalizeAdminChatStage(stage string) string {
 }
 
 func applyAdminChatOwnershipFilter(db *gorm.DB, filter string, principal Principal) {
-	switch filter {
-	case adminChatFilterMine:
-		db.Where("cp_me.id IS NOT NULL")
-	case adminChatFilterUnassigned:
-		db.Where(`NOT EXISTS (
-			SELECT 1 FROM chat_participants AS cp_support
-			WHERE cp_support.conversation_id = c.id
-			  AND cp_support.participant_type = ?
-			  AND cp_support.role = ?
-		)`, "admin", "support")
-	case adminChatFilterAll:
-		return
-	default:
-		db.Where("cp_me.participant_type = ? AND cp_me.participant_id = ?", principal.Type, principal.ID)
-	}
+	condition, args := adminChatOwnershipCondition(filter, principal)
+	db.Where(condition, args...)
 }
 
 func applyAdminChatStageFilter(db *gorm.DB, stage string, principal Principal) {
+	condition, args := adminChatStageCondition(stage, principal)
+	db.Where(condition, args...)
+}
+
+func adminChatOwnershipCondition(filter string, principal Principal) (string, []interface{}) {
+	switch filter {
+	case adminChatFilterAll:
+		return "1 = 1", nil
+	case adminChatFilterUnassigned:
+		return `NOT EXISTS (
+			SELECT 1 FROM chat_participants AS cp_support
+			WHERE cp_support.conversation_id = c.id
+			  AND cp_support.participant_type = 'admin'
+			  AND cp_support.role = 'support'
+		)`, nil
+	case adminChatFilterMine:
+		fallthrough
+	default:
+		return "cp_me.id IS NOT NULL", nil
+	}
+}
+
+func adminChatStageCondition(stage string, principal Principal) (string, []interface{}) {
+	latestID := "COALESCE(explicit_lo.id, listing_lo.id)"
+	latestStatus := "COALESCE(explicit_lo.status, listing_lo.status)"
+	latestRefundStatus := "COALESCE(explicit_lo.refund_status, listing_lo.refund_status)"
 	switch stage {
 	case adminChatStagePending:
-		db.Where(`(
-			lm.sender_type = ?
-			OR (
-				cp_me.id IS NOT NULL
-				AND EXISTS (
-					SELECT 1
-					FROM chat_messages AS cm_pending
-					WHERE cm_pending.conversation_id = c.id
-					  AND NOT (cm_pending.sender_type = ? AND cm_pending.sender_id = ?)
-					  AND (cp_me.last_read_at IS NULL OR cm_pending.created_at > cp_me.last_read_at)
-				)
+		return `(
+			lm.sender_type = 'user'
+			OR EXISTS (
+				SELECT 1
+				FROM chat_messages AS cm_pending
+				WHERE cm_pending.conversation_id = c.id
+				  AND cm_pending.sender_type <> 'system'
+				  AND NOT (cm_pending.sender_type = 'admin' AND cm_pending.sender_id = ?)
+				  AND cm_pending.id > COALESCE(cas.last_read_message_id, 0)
 			)
-		)`, "user", principal.Type, principal.ID)
+		)`, []interface{}{principal.ID}
 	case adminChatStageUnjoined:
-		db.Where("lo.id IS NULL")
+		return latestID + " IS NULL", nil
 	case adminChatStageHandoff:
-		db.Where("lo.status = ?", "pending_handoff")
+		return latestStatus + " = 'pending_handoff'", nil
 	case adminChatStageRenting:
-		db.Where("lo.status IN ?", []string{"renting", "overdue"})
+		return latestStatus + " IN ('renting', 'overdue')", nil
 	case adminChatStageAfterSale:
-		db.Where("(lo.status IN ? OR (lo.refund_status IS NOT NULL AND lo.refund_status <> ?))",
-			[]string{"pending_checkout_confirm", "pending_checkout_accept", "checkout_disputing", "abnormal"}, "none")
+		return "(" + latestStatus + " IN ('pending_checkout_confirm', 'pending_checkout_accept', 'checkout_disputing', 'abnormal') OR (" + latestRefundStatus + " IS NOT NULL AND " + latestRefundStatus + " <> 'none'))", nil
 	case adminChatStageEnded:
-		db.Where("(c.status IN ? OR lo.status IN ?)", []string{"archived", "closed"}, []string{"completed", "cancelled", "closed"})
+		return "(c.status IN ('archived', 'closed') OR " + latestStatus + " IN ('completed', 'cancelled', 'closed'))", nil
 	case adminChatStageAll:
-		return
+		fallthrough
+	default:
+		return "1 = 1", nil
 	}
 }
 

backend/migrations/000056_chat_admin_state_and_indexes.sql

@@ -0,0 +1,67 @@
+-- +goose Up
+-- +goose StatementBegin
+
+CREATE TABLE IF NOT EXISTS chat_admin_conversation_states (
+  id BIGINT UNSIGNED PRIMARY KEY AUTO_INCREMENT,
+  conversation_id BIGINT UNSIGNED NOT NULL COMMENT '会话ID',
+  admin_user_id BIGINT UNSIGNED NOT NULL COMMENT '管理员ID',
+  remark VARCHAR(128) NOT NULL DEFAULT '' COMMENT '管理员个人备注',
+  last_read_message_id BIGINT UNSIGNED NOT NULL DEFAULT 0 COMMENT '最后已读消息ID',
+  last_read_at DATETIME NULL COMMENT '最后已读时间',
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  UNIQUE KEY uk_chat_admin_conversation_state (conversation_id, admin_user_id),
+  KEY idx_chat_admin_state_admin (admin_user_id, conversation_id),
+  KEY idx_chat_admin_state_read (admin_user_id, last_read_message_id)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='管理员会话个人状态';
+
+INSERT INTO chat_admin_conversation_states (
+  conversation_id, admin_user_id, remark, last_read_message_id, last_read_at
+)
+SELECT
+  cp.conversation_id,
+  cp.participant_id,
+  cp.remark,
+  COALESCE((
+    SELECT MAX(cm.id)
+    FROM chat_messages cm
+    WHERE cm.conversation_id = cp.conversation_id
+      AND cp.last_read_at IS NOT NULL
+      AND cm.created_at <= cp.last_read_at
+  ), 0),
+  cp.last_read_at
+FROM chat_participants cp
+WHERE cp.participant_type = 'admin'
+  AND (cp.remark <> '' OR cp.last_read_at IS NOT NULL)
+ON DUPLICATE KEY UPDATE
+  remark = VALUES(remark),
+  last_read_message_id = GREATEST(last_read_message_id, VALUES(last_read_message_id)),
+  last_read_at = CASE
+    WHEN last_read_at IS NULL THEN VALUES(last_read_at)
+    WHEN VALUES(last_read_at) IS NULL THEN last_read_at
+    ELSE GREATEST(last_read_at, VALUES(last_read_at))
+  END;
+
+ALTER TABLE chat_conversations
+  ADD INDEX idx_chat_conversations_status_activity (status, last_message_at, id),
+  ADD INDEX idx_chat_conversations_type_scene_activity (type, support_scene, last_message_at, id);
+
+-- 后台客服列表需要按商品快速定位最新订单，避免为每个会话执行全表排序。
+ALTER TABLE rental_orders
+  ADD INDEX idx_rental_orders_listing_id_id (listing_id, id);
+
+-- +goose StatementEnd
+
+-- +goose Down
+-- +goose StatementBegin
+
+ALTER TABLE rental_orders
+  DROP INDEX idx_rental_orders_listing_id_id;
+
+ALTER TABLE chat_conversations
+  DROP INDEX idx_chat_conversations_type_scene_activity,
+  DROP INDEX idx_chat_conversations_status_activity;
+
+DROP TABLE IF EXISTS chat_admin_conversation_states;
+
+-- +goose StatementEnd