修正订单群聊与发布跳转

backend/internal/modules/chat/conversation.go

@@ -87,8 +87,34 @@ func (r *Repository) FindConversation(ctx context.Context, principal Principal,
 	return &dto, nil
 }
 func (r *Repository) FindOrderConversation(ctx context.Context, userID uint64, orderID uint64) (*ConversationDTO, error) {
-	var row conversationRow
 	principal := Principal{Type: "user", ID: userID}
+	var order model.RentalOrder
+	if err := r.db.WithContext(ctx).First(&order, orderID).Error; err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrConversationNotFound
+		}
+		return nil, err
+	}
+
+	if order.ListingID > 0 {
+		var row conversationRow
+		err := r.conversationQuery(ctx, principal).
+			Where("c.listing_id = ? AND c.type = ?", order.ListingID, ConversationTypeListingGroup).
+			First(&row).Error
+		if err == nil {
+			participants, err := r.participants(ctx, row.ID)
+			if err != nil {
+				return nil, err
+			}
+			dto := row.toDTO(participants)
+			return &dto, nil
+		}
+		if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, err
+		}
+	}
+
+	var row conversationRow
 	err := r.conversationQuery(ctx, principal).Where("c.order_id = ?", orderID).First(&row).Error
 	if err != nil {
 		if errors.Is(err, gorm.ErrRecordNotFound) {

backend/internal/modules/chat/conversation_test.go

@@ -0,0 +1,152 @@
+package chat
+
+import (
+	"testing"
+	"time"
+
+	"hfb_sys/backend/internal/model"
+
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+)
+
+func setupConversationTestDB(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("无法创建测试数据库: %v", err)
+	}
+	if err := db.AutoMigrate(
+		&model.User{},
+		&model.RentalOrder{},
+		&model.ChatConversation{},
+		&model.ChatParticipant{},
+		&model.ChatMessage{},
+	); err != nil {
+		t.Fatalf("数据库迁移失败: %v", err)
+	}
+	return db
+}
+
+func TestFindOrderConversationPrefersListingGroup(t *testing.T) {
+	db := setupConversationTestDB(t)
+	repo := NewRepository(db, nil)
+	now := time.Date(2026, 6, 18, 12, 0, 0, 0, time.UTC)
+
+	owner := model.User{Phone: "13800001001", Nickname: "号主"}
+	renter := model.User{Phone: "13800001002", Nickname: "租客"}
+	if err := db.Create(&owner).Error; err != nil {
+		t.Fatalf("创建号主失败: %v", err)
+	}
+	if err := db.Create(&renter).Error; err != nil {
+		t.Fatalf("创建租客失败: %v", err)
+	}
+
+	order := model.RentalOrder{
+		OrderNo:   "ORDER-LISTING-GROUP",
+		ListingID: 101,
+		AccountID: 201,
+		OwnerID:   owner.ID,
+		RenterID:  renter.ID,
+		Status:    "renting",
+	}
+	if err := db.Create(&order).Error; err != nil {
+		t.Fatalf("创建订单失败: %v", err)
+	}
+	orderConv := model.ChatConversation{
+		OrderID: &order.ID,
+		Type:    ConversationTypeOrderGroup,
+		Title:   "旧订单群",
+		Status:  "active",
+	}
+	listingConv := model.ChatConversation{
+		ListingID: &order.ListingID,
+		Type:      ConversationTypeListingGroup,
+		Title:     "发布群",
+		Status:    "active",
+	}
+	if err := db.Create(&orderConv).Error; err != nil {
+		t.Fatalf("创建订单群失败: %v", err)
+	}
+	if err := db.Create(&listingConv).Error; err != nil {
+		t.Fatalf("创建发布群失败: %v", err)
+	}
+	participants := []model.ChatParticipant{
+		{ConversationID: orderConv.ID, ParticipantType: "user", ParticipantID: order.RenterID, Role: "renter", JoinedAt: now},
+		{ConversationID: listingConv.ID, ParticipantType: "user", ParticipantID: order.RenterID, Role: "renter", JoinedAt: now},
+	}
+	if err := db.Create(&participants).Error; err != nil {
+		t.Fatalf("创建成员失败: %v", err)
+	}
+
+	dto, err := repo.FindOrderConversation(t.Context(), order.RenterID, order.ID)
+	if err != nil {
+		t.Fatalf("查询订单会话失败: %v", err)
+	}
+	if dto.ID != listingConv.ID {
+		t.Fatalf("会话 ID = %d, want 发布群 %d", dto.ID, listingConv.ID)
+	}
+	if dto.Type != ConversationTypeListingGroup {
+		t.Fatalf("会话类型 = %q, want %q", dto.Type, ConversationTypeListingGroup)
+	}
+}
+
+func TestFindOrderConversationFallsBackToOrderGroup(t *testing.T) {
+	db := setupConversationTestDB(t)
+	repo := NewRepository(db, nil)
+	now := time.Date(2026, 6, 18, 12, 0, 0, 0, time.UTC)
+
+	owner := model.User{Phone: "13800001003", Nickname: "号主"}
+	renter := model.User{Phone: "13800001004", Nickname: "租客"}
+	if err := db.Create(&owner).Error; err != nil {
+		t.Fatalf("创建号主失败: %v", err)
+	}
+	if err := db.Create(&renter).Error; err != nil {
+		t.Fatalf("创建租客失败: %v", err)
+	}
+
+	order := model.RentalOrder{
+		OrderNo:   "ORDER-LEGACY-GROUP",
+		ListingID: 102,
+		AccountID: 202,
+		OwnerID:   owner.ID,
+		RenterID:  renter.ID,
+		Status:    "renting",
+	}
+	if err := db.Create(&order).Error; err != nil {
+		t.Fatalf("创建订单失败: %v", err)
+	}
+	orderConv := model.ChatConversation{
+		OrderID: &order.ID,
+		Type:    ConversationTypeOrderGroup,
+		Title:   "旧订单群",
+		Status:  "active",
+	}
+	if err := db.Create(&orderConv).Error; err != nil {
+		t.Fatalf("创建订单群失败: %v", err)
+	}
+	participant := model.ChatParticipant{
+		ConversationID:  orderConv.ID,
+		ParticipantType: "user",
+		ParticipantID:   order.RenterID,
+		Role:            "renter",
+		JoinedAt:        now,
+	}
+	if err := db.Create(&participant).Error; err != nil {
+		t.Fatalf("创建成员失败: %v", err)
+	}
+
+	dto, err := repo.FindOrderConversation(t.Context(), order.RenterID, order.ID)
+	if err != nil {
+		t.Fatalf("查询订单会话失败: %v", err)
+	}
+	if dto.ID != orderConv.ID {
+		t.Fatalf("会话 ID = %d, want 订单群 %d", dto.ID, orderConv.ID)
+	}
+	if dto.Type != ConversationTypeOrderGroup {
+		t.Fatalf("会话类型 = %q, want %q", dto.Type, ConversationTypeOrderGroup)
+	}
+}