feat: support optional file cleanup when deleting conversations

backend/docs/docs.go

@@ -4160,7 +4160,7 @@ const docTemplate = `{
                         "BearerAuth": []
                     }
                 ],
-                "description": "删除当前用户项目分组。默认仅解除其下会话归属；delete_conversations=true 时同时软删除项目内会话。",
+                "description": "删除当前用户项目分组。默认仅解除其下会话归属；delete_conversations=true 时同时软删除项目内会话；delete_files=true 时同步删除不再被其他会话引用的文件。",
                 "consumes": [
                     "application/json"
                 ],
@@ -4184,6 +4184,12 @@ const docTemplate = `{
                         "description": "是否同时删除项目内会话",
                         "name": "delete_conversations",
                         "in": "query"
+                    },
+                    {
+                        "type": "boolean",
+                        "description": "是否同步删除不再被其他会话引用的会话文件",
+                        "name": "delete_files",
+                        "in": "query"
                     }
                 ],
                 "responses": {
@@ -4675,6 +4681,12 @@ const docTemplate = `{
                         "name": "id",
                         "in": "path",
                         "required": true
+                    },
+                    {
+                        "type": "boolean",
+                        "description": "是否同步删除不再被其他会话引用的会话文件",
+                        "name": "delete_files",
+                        "in": "query"
                     }
                 ],
                 "responses": {
@@ -10168,6 +10180,12 @@ const docTemplate = `{
             "properties": {
                 "deleted": {
                     "type": "boolean"
+                },
+                "deletedFileCount": {
+                    "type": "integer"
+                },
+                "quota": {
+                    "$ref": "#/definitions/internal_transport_http_conversation.StorageQuotaResponse"
                 }
             }
         },

backend/docs/swagger.json

@@ -4153,7 +4153,7 @@
                         "BearerAuth": []
                     }
                 ],
-                "description": "删除当前用户项目分组。默认仅解除其下会话归属；delete_conversations=true 时同时软删除项目内会话。",
+                "description": "删除当前用户项目分组。默认仅解除其下会话归属；delete_conversations=true 时同时软删除项目内会话；delete_files=true 时同步删除不再被其他会话引用的文件。",
                 "consumes": [
                     "application/json"
                 ],
@@ -4177,6 +4177,12 @@
                         "description": "是否同时删除项目内会话",
                         "name": "delete_conversations",
                         "in": "query"
+                    },
+                    {
+                        "type": "boolean",
+                        "description": "是否同步删除不再被其他会话引用的会话文件",
+                        "name": "delete_files",
+                        "in": "query"
                     }
                 ],
                 "responses": {
@@ -4668,6 +4674,12 @@
                         "name": "id",
                         "in": "path",
                         "required": true
+                    },
+                    {
+                        "type": "boolean",
+                        "description": "是否同步删除不再被其他会话引用的会话文件",
+                        "name": "delete_files",
+                        "in": "query"
                     }
                 ],
                 "responses": {
@@ -10161,6 +10173,12 @@
             "properties": {
                 "deleted": {
                     "type": "boolean"
+                },
+                "deletedFileCount": {
+                    "type": "integer"
+                },
+                "quota": {
+                    "$ref": "#/definitions/internal_transport_http_conversation.StorageQuotaResponse"
                 }
             }
         },

backend/docs/swagger.yaml

@@ -2397,6 +2397,10 @@ definitions:
     properties:
       deleted:
         type: boolean
+      deletedFileCount:
+        type: integer
+      quota:
+        $ref: '#/definitions/internal_transport_http_conversation.StorageQuotaResponse'
     type: object
   internal_transport_http_conversation.ConversationDeleteResponseDoc:
     properties:
@@ -5974,7 +5978,8 @@ paths:
     delete:
       consumes:
       - application/json
-      description: 删除当前用户项目分组。默认仅解除其下会话归属；delete_conversations=true 时同时软删除项目内会话。
+      description: 删除当前用户项目分组。默认仅解除其下会话归属；delete_conversations=true 时同时软删除项目内会话；delete_files=true
+        时同步删除不再被其他会话引用的文件。
       parameters:
       - description: 项目 public_id
         in: path
@@ -5985,6 +5990,10 @@ paths:
         in: query
         name: delete_conversations
         type: boolean
+      - description: 是否同步删除不再被其他会话引用的会话文件
+        in: query
+        name: delete_files
+        type: boolean
       produces:
       - application/json
       responses:
@@ -6227,6 +6236,10 @@ paths:
         name: id
         required: true
         type: string
+      - description: 是否同步删除不再被其他会话引用的会话文件
+        in: query
+        name: delete_files
+        type: boolean
       produces:
       - application/json
       responses:

backend/internal/application/conversation/service_conversation.go

@@ -15,6 +15,18 @@ const (
 	maxPageSize     = 100
 )
 
+// DeleteConversationOptions 定义会话删除选项。
+type DeleteConversationOptions struct {
+	DeleteFiles bool
+}
+
+// DeleteConversationResult 返回会话删除结果。
+type DeleteConversationResult struct {
+	Deleted          bool
+	DeletedFileCount int
+	Quota            *model.StorageQuota
+}
+
 // CreateConversation 创建用户新会话。
 func (s *Service) CreateConversation(ctx context.Context, userID uint, title string, modelName string, projectPublicID string) (*model.Conversation, error) {
 	normalizedTitle := strings.TrimSpace(title)
@@ -218,15 +230,20 @@ func (s *Service) SetConversationArchived(ctx context.Context, userID uint, publ
 	return item, nil
 }
 
-// DeleteConversation 删除会话（软删除）。
-func (s *Service) DeleteConversation(ctx context.Context, userID uint, publicID string) error {
-	if err := s.repo.DeleteConversationByPublicID(ctx, userID, publicID); err != nil {
+// DeleteConversation 删除会话（软删除），并按需清理不再被其他会话引用的文件。
+func (s *Service) DeleteConversation(ctx context.Context, userID uint, publicID string, options DeleteConversationOptions) (*DeleteConversationResult, error) {
+	cleanupFileIDs, err := s.repo.DeleteConversationByPublicID(ctx, userID, publicID, options.DeleteFiles)
+	if err != nil {
 		if errors.Is(err, repository.ErrNotFound) {
-			return ErrConversationNotFound
+			return nil, ErrConversationNotFound
 		}
-		return err
+		return nil, err
+	}
+	result := &DeleteConversationResult{Deleted: true}
+	if options.DeleteFiles {
+		result.DeletedFileCount, result.Quota = s.deleteConversationFiles(ctx, userID, cleanupFileIDs)
 	}
-	return nil
+	return result, nil
 }
 
 // GetConversation 查询用户会话元信息。

backend/internal/application/conversation/service_file_cleanup.go

@@ -0,0 +1,42 @@
+package conversation
+
+import (
+	"context"
+	"strings"
+
+	model "github.com/DEEIX-AI/DEEIX-Chat/backend/internal/domain/conversation"
+	"go.uber.org/zap"
+)
+
+// deleteConversationFiles 清理会话删除后不再被其他活跃会话引用的文件。
+func (s *Service) deleteConversationFiles(ctx context.Context, userID uint, fileIDs []string) (int, *model.StorageQuota) {
+	if len(fileIDs) == 0 || s.uploadSvc == nil {
+		return 0, nil
+	}
+	deletedCount := 0
+	var latestQuota *model.StorageQuota
+	for _, rawFileID := range fileIDs {
+		fileID := strings.TrimSpace(rawFileID)
+		if fileID == "" {
+			continue
+		}
+		result, deleted, err := s.uploadSvc.DeleteFileIfUnreferenced(ctx, userID, fileID)
+		if err != nil {
+			if s.logger != nil {
+				s.logger.Warn("delete_conversation_file_failed",
+					zap.Uint("user_id", userID),
+					zap.String("file_id", fileID),
+					zap.Error(err),
+				)
+			}
+			continue
+		}
+		if !deleted || result == nil {
+			continue
+		}
+		deletedCount++
+		quota := result.Quota
+		latestQuota = &quota
+	}
+	return deletedCount, latestQuota
+}

backend/internal/application/conversation/service_project.go

@@ -82,14 +82,31 @@ func (s *Service) UpdateConversationProject(
 }
 
 // DeleteConversationProject 删除当前用户项目分组。
-func (s *Service) DeleteConversationProject(ctx context.Context, userID uint, publicID string, deleteConversations bool) error {
-	if err := s.repo.DeleteConversationProjectByPublicID(ctx, userID, strings.TrimSpace(publicID), deleteConversations); err != nil {
+func (s *Service) DeleteConversationProject(
+	ctx context.Context,
+	userID uint,
+	publicID string,
+	deleteConversations bool,
+	options DeleteConversationOptions,
+) (*DeleteConversationResult, error) {
+	cleanupFileIDs, err := s.repo.DeleteConversationProjectByPublicID(
+		ctx,
+		userID,
+		strings.TrimSpace(publicID),
+		deleteConversations,
+		deleteConversations && options.DeleteFiles,
+	)
+	if err != nil {
 		if errors.Is(err, repository.ErrNotFound) {
-			return ErrConversationProjectNotFound
+			return nil, ErrConversationProjectNotFound
 		}
-		return err
+		return nil, err
 	}
-	return nil
+	result := &DeleteConversationResult{Deleted: true}
+	if deleteConversations && options.DeleteFiles {
+		result.DeletedFileCount, result.Quota = s.deleteConversationFiles(ctx, userID, cleanupFileIDs)
+	}
+	return result, nil
 }
 
 // ReorderConversationProjects 更新当前用户项目展示顺序。

backend/internal/application/upload/service.go

@@ -348,7 +348,7 @@ func (s *Service) tryReuseExistingFile(
 					zap.String("path", existingFile.StoragePath),
 				)
 			}
-			deletedFile, _, shouldRemovePhysical, deleteErr := s.repo.DeleteFileObjectAndReleaseQuota(ctx, userID, existingFile.FileID, quotaBytes)
+			deletedFile, _, shouldRemovePhysical, deleteErr := s.repo.DeleteFileObjectAndReleaseQuota(ctx, userID, existingFile.FileID, quotaBytes, repository.DeleteFileObjectOptions{})
 			if deleteErr != nil {
 				return nil, false, deleteErr
 			}
@@ -413,15 +413,28 @@ func objectMatchesContent(ctx context.Context, store objectstore.Store, path str
 
 // DeleteFile 删除文件并回收配额。
 func (s *Service) DeleteFile(ctx context.Context, userID uint, fileID string) (*DeleteFileResult, error) {
+	result, _, err := s.deleteFile(ctx, userID, fileID, repository.DeleteFileObjectOptions{})
+	return result, err
+}
+
+// DeleteFileIfUnreferenced 仅在文件未被活跃会话引用时删除文件并回收配额。
+func (s *Service) DeleteFileIfUnreferenced(ctx context.Context, userID uint, fileID string) (*DeleteFileResult, bool, error) {
+	return s.deleteFile(ctx, userID, fileID, repository.DeleteFileObjectOptions{RequireUnreferenced: true})
+}
+
+func (s *Service) deleteFile(ctx context.Context, userID uint, fileID string, options repository.DeleteFileObjectOptions) (*DeleteFileResult, bool, error) {
 	normalizedFileID := strings.TrimSpace(fileID)
 	if normalizedFileID == "" {
-		return nil, s.errInvalidFileReference()
+		return nil, false, s.errInvalidFileReference()
 	}
 
 	cfg := s.snapshot()
-	deletedFile, quota, shouldRemovePhysical, err := s.repo.DeleteFileObjectAndReleaseQuota(ctx, userID, normalizedFileID, cfg.UserStorageQuotaBytes)
+	deletedFile, quota, shouldRemovePhysical, err := s.repo.DeleteFileObjectAndReleaseQuota(ctx, userID, normalizedFileID, cfg.UserStorageQuotaBytes, options)
 	if err != nil {
-		return nil, err
+		if options.RequireUnreferenced && errors.Is(err, repository.ErrConflict) {
+			return nil, false, nil
+		}
+		return nil, false, err
 	}
 	if shouldRemovePhysical {
 		store, storeErr := s.openObjectStore(ctx)
@@ -442,7 +455,7 @@ func (s *Service) DeleteFile(ctx context.Context, userID uint, fileID string) (*
 		Deleted: true,
 		FileID:  normalizedFileID,
 		Quota:   *quota,
-	}, nil
+	}, true, nil
 }
 
 // RenameFile 重命名当前用户文件。

backend/internal/application/upload/service_test.go

@@ -85,6 +85,33 @@ func TestUploadFileAllowsReuploadAfterDelete(t *testing.T) {
 	}
 }
 
+func TestDeleteFileIfUnreferencedSkipsReferencedFile(t *testing.T) {
+	ctx := context.Background()
+	repo := newUploadTestRepo()
+	store := newUploadTestStore()
+	service := newUploadTestService(repo, store)
+
+	uploaded, err := service.UploadFile(ctx, uploadTestInput("notes.md", "same content"))
+	if err != nil {
+		t.Fatalf("upload failed: %v", err)
+	}
+	repo.referencedFileIDs[uploaded.File.FileID] = true
+
+	result, deleted, err := service.DeleteFileIfUnreferenced(ctx, 1, uploaded.File.FileID)
+	if err != nil {
+		t.Fatalf("delete if unreferenced failed: %v", err)
+	}
+	if deleted || result != nil {
+		t.Fatal("referenced file should be skipped without returning a delete result")
+	}
+	if status := repo.fileStatus(uploaded.File.FileID); status != "active" {
+		t.Fatalf("referenced file should remain active, got %q", status)
+	}
+	if got := store.objectCount(); got != 1 {
+		t.Fatalf("referenced file should keep physical object, got %d objects", got)
+	}
+}
+
 func TestUploadFileReplacesStaleDuplicatePointer(t *testing.T) {
 	ctx := context.Background()
 	repo := newUploadTestRepo()
@@ -301,6 +328,7 @@ type uploadTestRepo struct {
 	quota                   domainconversation.StorageQuota
 	missNextDuplicateLookup bool
 	failNextCreateDuplicate bool
+	referencedFileIDs       map[string]bool
 }
 
 func newUploadTestRepo() *uploadTestRepo {
@@ -310,6 +338,7 @@ func newUploadTestRepo() *uploadTestRepo {
 			UserID:     1,
 			QuotaBytes: 10 * 1024 * 1024,
 		},
+		referencedFileIDs: make(map[string]bool),
 	}
 }
 
@@ -392,14 +421,17 @@ func (r *uploadTestRepo) CreateFileObjectAndConsumeQuota(_ context.Context, item
 	return cloneQuota(r.quota), nil
 }
 
-func (r *uploadTestRepo) DeleteFileObjectAndReleaseQuota(_ context.Context, userID uint, fileID string, quotaLimit int64) (*domainconversation.FileObject, *domainconversation.StorageQuota, bool, error) {
+func (r *uploadTestRepo) DeleteFileObjectAndReleaseQuota(_ context.Context, userID uint, fileID string, quotaLimit int64, options repository.DeleteFileObjectOptions) (*domainconversation.FileObject, *domainconversation.StorageQuota, bool, error) {
 	if quotaLimit > 0 {
 		r.quota.QuotaBytes = quotaLimit
 	}
 	for i := range r.files {
 		if r.files[i].UserID != userID || r.files[i].FileID != fileID || r.files[i].Status != "active" {
 			continue
 		}
+		if options.RequireUnreferenced && r.referencedFileIDs[fileID] {
+			return nil, nil, false, repository.ErrConflict
+		}
 		deleted := r.files[i]
 		r.files[i].Status = "deleted"
 		remainingRefs := 0