feat: better previews and consistent previews

tests/engine/PreviewServer.test.ts

@@ -174,6 +174,14 @@ describe('PreviewServer', () => {
     const lightboxJsResponse = await fetch(`${server.getBaseUrl()}/assets/lightbox.min.js`);
     expect(lightboxJsResponse.status).toBe(200);
     expect(lightboxJsResponse.headers.get('content-type')).toContain('application/javascript');
+
+    const lightboxPrevImageResponse = await fetch(`${server.getBaseUrl()}/images/prev.png`);
+    expect(lightboxPrevImageResponse.status).toBe(200);
+    expect(lightboxPrevImageResponse.headers.get('content-type')).toContain('image/png');
+
+    const lightboxLoadingImageResponse = await fetch(`${server.getBaseUrl()}/images/loading.gif`);
+    expect(lightboxLoadingImageResponse.status).toBe(200);
+    expect(lightboxLoadingImageResponse.headers.get('content-type')).toContain('image/gif');
   });
 
   it('limits list routes to 50 posts', async () => {

tests/engine/mainStartup.test.ts

@@ -114,4 +114,167 @@ describe('main bootstrap preview behavior', () => {
     expect(mockPreviewStart).toHaveBeenCalledWith(4123);
     expect(mockApp.whenReady).toHaveBeenCalled();
   });
+
+  it('enables Blog Preview Post only for active post tab and opens canonical URL', async () => {
+    const mockApp = {
+      name: 'bDS',
+      whenReady: vi.fn(() => Promise.resolve()),
+      on: vi.fn(),
+      quit: vi.fn(),
+    };
+
+    const mockBrowserWindowGetAllWindows = vi.fn(() => [{ id: 1 }]);
+
+    class MockBrowserWindow {
+      static getAllWindows = mockBrowserWindowGetAllWindows;
+
+      loadURL = vi.fn();
+      loadFile = vi.fn();
+      on = vi.fn();
+      isDestroyed = vi.fn(() => false);
+      webContents = {
+        on: vi.fn(),
+        send: vi.fn(),
+        openDevTools: vi.fn(),
+        toggleDevTools: vi.fn(),
+      };
+    }
+
+    const findMenuItemById = (template: any[], id: string): any | null => {
+      for (const item of template) {
+        if (item && item.id === id) {
+          return item;
+        }
+        if (item?.submenu && Array.isArray(item.submenu)) {
+          const found = findMenuItemById(item.submenu, id);
+          if (found) return found;
+        }
+      }
+      return null;
+    };
+
+    let capturedTemplate: any[] = [];
+    const menuObject = {
+      getMenuItemById: (id: string) => findMenuItemById(capturedTemplate, id),
+    };
+
+    const ipcMainHandle = vi.fn();
+    const shellOpenExternal = vi.fn().mockResolvedValue(undefined);
+
+    vi.doMock('electron', () => ({
+      app: mockApp,
+      BrowserWindow: MockBrowserWindow,
+      Menu: {
+        buildFromTemplate: vi.fn((template: any[]) => {
+          capturedTemplate = template;
+          return menuObject;
+        }),
+        setApplicationMenu: vi.fn(),
+        getApplicationMenu: vi.fn(() => menuObject),
+      },
+      ipcMain: {
+        on: vi.fn(),
+        handle: ipcMainHandle,
+        removeHandler: vi.fn(),
+      },
+      protocol: {
+        registerSchemesAsPrivileged: vi.fn(),
+        handle: vi.fn(),
+      },
+      net: {
+        fetch: vi.fn(),
+      },
+      shell: {
+        openExternal: shellOpenExternal,
+        openPath: vi.fn(),
+      },
+    }));
+
+    const mockPreviewStart = vi.fn().mockResolvedValue(4123);
+    const mockPreviewStop = vi.fn().mockResolvedValue(undefined);
+    const mockPreviewGetBaseUrl = vi.fn(() => 'http://127.0.0.1:4123');
+
+    class MockPreviewServer {
+      start = mockPreviewStart;
+      stop = mockPreviewStop;
+      getBaseUrl = mockPreviewGetBaseUrl;
+    }
+
+    vi.doMock('../../src/main/engine/PreviewServer', () => ({
+      PreviewServer: MockPreviewServer,
+    }));
+
+    const postCreatedAt = new Date('2026-02-17T10:00:00.000Z');
+    const getPost = vi.fn().mockResolvedValue({
+      id: 'post-42',
+      slug: 'current-post',
+      createdAt: postCreatedAt,
+    });
+
+    vi.doMock('../../src/main/engine/PostEngine', () => ({
+      getPostEngine: vi.fn(() => ({
+        getPost,
+      })),
+    }));
+
+    vi.doMock('../../src/main/database', () => ({
+      getDatabase: vi.fn(() => ({
+        initializeLocal: vi.fn().mockResolvedValue(undefined),
+        close: vi.fn().mockResolvedValue(undefined),
+        getLocal: vi.fn(() => ({
+          select: vi.fn(() => ({
+            from: vi.fn(() => ({
+              where: vi.fn(() => ({
+                get: vi.fn().mockResolvedValue(null),
+              })),
+            })),
+          })),
+        })),
+        getDataPaths: vi.fn(() => ({ database: '/tmp/mock.db' })),
+      })),
+    }));
+
+    vi.doMock('../../src/main/ipc', () => ({
+      registerIpcHandlers: vi.fn(),
+      registerChatHandlers: vi.fn(),
+      initializeChatHandlers: vi.fn(),
+      cleanupChatHandlers: vi.fn().mockResolvedValue(undefined),
+    }));
+
+    vi.doMock('../../src/main/database/schema', () => ({
+      media: {},
+    }));
+
+    vi.doMock('drizzle-orm', () => ({
+      eq: vi.fn(),
+    }));
+
+    vi.doMock('../../src/main/engine/MediaEngine', () => ({
+      getMediaEngine: vi.fn(() => ({
+        getThumbnailPaths: vi.fn().mockResolvedValue({ small: null }),
+      })),
+    }));
+
+    await import('../../src/main/main');
+    await new Promise((resolve) => setTimeout(resolve, 0));
+
+    const previewMenuItem = findMenuItemById(capturedTemplate, 'blog.previewPost');
+    expect(previewMenuItem).toBeTruthy();
+    expect(previewMenuItem.enabled).toBe(false);
+
+    const setPreviewTargetCall = ipcMainHandle.mock.calls.find((call: unknown[]) => call[0] === 'app:setPreviewPostTarget');
+    expect(setPreviewTargetCall).toBeTruthy();
+    const setPreviewTargetHandler = setPreviewTargetCall?.[1] as ((event: unknown, postId: string | null) => Promise<void>);
+
+    await setPreviewTargetHandler({}, 'post-42');
+    expect(previewMenuItem.enabled).toBe(true);
+
+    await previewMenuItem.click();
+
+    expect(getPost).toHaveBeenCalledWith('post-42');
+    expect(shellOpenExternal).toHaveBeenCalledWith('http://127.0.0.1:4123/2026/02/17/current-post');
+
+    await setPreviewTargetHandler({}, null);
+    expect(previewMenuItem.enabled).toBe(false);
+  });
 });