fix: debounce untitled H1 filename sync

src/hooks/useAppSave.test.ts

@@ -1,14 +1,17 @@
-import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest'
 import { renderHook, act } from '@testing-library/react'
 import { useAppSave } from './useAppSave'
 import type { VaultEntry } from '../types'
+import { isTauri } from '../mock-tauri'
+import { invoke } from '@tauri-apps/api/core'
 
 vi.mock('@tauri-apps/api/core', () => ({
   invoke: vi.fn().mockResolvedValue(undefined),
 }))
 vi.mock('../mock-tauri', () => ({
-  isTauri: () => false,
+  isTauri: vi.fn(() => false),
   mockInvoke: vi.fn().mockResolvedValue(undefined),
+  updateMockContent: vi.fn(),
 }))
 
 function makeEntry(path: string, title = 'Test', filename = 'test.md'): VaultEntry {
@@ -32,12 +35,18 @@ describe('useAppSave', () => {
 
   beforeEach(() => {
     vi.clearAllMocks()
+    vi.useRealTimers()
+    vi.mocked(isTauri).mockReturnValue(false)
     deps.unsavedPaths = new Set()
     deps.tabs = []
     deps.activeTabPath = null
     deps.handleRenameNote.mockResolvedValue(undefined)
   })
 
+  afterEach(() => {
+    vi.useRealTimers()
+  })
+
   function renderSave(overrides = {}) {
     return renderHook(() => useAppSave({ ...deps, ...overrides }))
   }
@@ -91,4 +100,85 @@ describe('useAppSave', () => {
     const { result } = renderSave()
     expect(typeof result.current.handleContentChange).toBe('function')
   })
+
+  it('debounces untitled H1 auto-rename until the user pauses typing', async () => {
+    vi.useFakeTimers()
+    vi.mocked(isTauri).mockReturnValue(true)
+    vi.mocked(invoke).mockImplementation(async (command: string, args?: Record<string, unknown>) => {
+      if (command === 'save_note_content') return undefined
+      if (command === 'auto_rename_untitled') return { new_path: '/vault/fresh-title.md', updated_files: 0 }
+      if (command === 'reload_vault_entry') return makeEntry('/vault/fresh-title.md', 'Fresh Title', 'fresh-title.md')
+      if (command === 'get_note_content' && args?.path === '/vault/fresh-title.md') return '# Fresh Title\n\nBody'
+      return undefined
+    })
+
+    const entry = makeEntry('/vault/untitled-note-123.md', 'Untitled Note 123', 'untitled-note-123.md')
+    const tabs = [{ entry, content: '# Fresh Title\n\nBody' }]
+    const { result } = renderSave({
+      tabs,
+      activeTabPath: entry.path,
+      unsavedPaths: new Set([entry.path]),
+    })
+
+    await act(async () => {
+      result.current.handleContentChange(entry.path, '# Fresh Title\n\nBody')
+      await vi.advanceTimersByTimeAsync(500)
+    })
+
+    expect(vi.mocked(invoke)).not.toHaveBeenCalledWith('auto_rename_untitled', expect.anything())
+
+    await act(async () => {
+      await vi.advanceTimersByTimeAsync(2_499)
+    })
+    expect(vi.mocked(invoke)).not.toHaveBeenCalledWith('auto_rename_untitled', expect.anything())
+
+    await act(async () => {
+      await vi.advanceTimersByTimeAsync(1)
+    })
+
+    expect(vi.mocked(invoke)).toHaveBeenCalledWith('auto_rename_untitled', {
+      vaultPath: '/vault',
+      notePath: entry.path,
+    })
+    expect(deps.replaceEntry).toHaveBeenCalledWith(
+      entry.path,
+      expect.objectContaining({ path: '/vault/fresh-title.md', filename: 'fresh-title.md' }),
+      '# Fresh Title\n\nBody',
+    )
+  })
+
+  it('cancels a pending untitled auto-rename when the user navigates away', async () => {
+    vi.useFakeTimers()
+    vi.mocked(isTauri).mockReturnValue(true)
+    vi.mocked(invoke).mockImplementation(async (command: string) => {
+      if (command === 'save_note_content') return undefined
+      if (command === 'auto_rename_untitled') return { new_path: '/vault/fresh-title.md', updated_files: 0 }
+      return undefined
+    })
+
+    const entry = makeEntry('/vault/untitled-note-123.md', 'Untitled Note 123', 'untitled-note-123.md')
+    const tabs = [{ entry, content: '# Fresh Title\n\nBody' }]
+    const { result, rerender } = renderHook(
+      ({ currentActiveTabPath }: { currentActiveTabPath: string | null }) => useAppSave({
+        ...deps,
+        tabs,
+        activeTabPath: currentActiveTabPath,
+        unsavedPaths: new Set([entry.path]),
+      }),
+      { initialProps: { currentActiveTabPath: entry.path } },
+    )
+
+    await act(async () => {
+      result.current.handleContentChange(entry.path, '# Fresh Title\n\nBody')
+      await vi.advanceTimersByTimeAsync(500)
+    })
+
+    rerender({ currentActiveTabPath: '/vault/other.md' })
+
+    await act(async () => {
+      await vi.advanceTimersByTimeAsync(2_500)
+    })
+
+    expect(vi.mocked(invoke)).not.toHaveBeenCalledWith('auto_rename_untitled', expect.anything())
+  })
 })