From 812dc6957e19ac2d220e94ed2b3e452afcc1c6aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jim=20Liu=20=E5=AE=9D=E7=8E=89?= <junminliu@gmail.com>
Date: Fri, 5 Jun 2026 22:12:31 -0500
Subject: [PATCH] Add searchable language picker

---
 .../src/components/language-switcher.test.tsx |  14 ++
 .../src/components/language-switcher.tsx      | 128 +++++++++++-------
 apps/desktop/src/i18n/en.ts                   |   4 +-
 apps/desktop/src/i18n/ja.ts                   |   4 +-
 apps/desktop/src/i18n/languages.ts            |  19 ++-
 apps/desktop/src/i18n/types.ts                |   2 +
 apps/desktop/src/i18n/zh-hant.ts              |   4 +-
 apps/desktop/src/i18n/zh.ts                   |   4 +-
 8 files changed, 119 insertions(+), 60 deletions(-)

diff --git a/apps/desktop/src/components/language-switcher.test.tsx b/apps/desktop/src/components/language-switcher.test.tsx
index 77614af22e5..3792012171a 100644
--- a/apps/desktop/src/components/language-switcher.test.tsx
+++ b/apps/desktop/src/components/language-switcher.test.tsx
@@ -6,6 +6,19 @@ import { type I18nConfigClient, I18nProvider } from '@/i18n'
 
 import { LanguageSwitcher } from './language-switcher'
 
+// cmdk (the searchable list) wires a ResizeObserver and scrolls the active
+// item into view — neither exists in jsdom. Stub them, matching the polyfill
+// idiom in tool-approval-group.test.tsx.
+class TestResizeObserver {
+  observe() {}
+  unobserve() {}
+  disconnect() {}
+}
+
+vi.stubGlobal('ResizeObserver', TestResizeObserver)
+
+Element.prototype.scrollIntoView = function scrollIntoView() {}
+
 describe('LanguageSwitcher', () => {
   afterEach(() => {
     cleanup()
@@ -15,6 +28,7 @@ describe('LanguageSwitcher', () => {
   it('persists language changes through display.language config', async () => {
     const saveConfig = vi.fn().mockResolvedValue({ ok: true })
     const latestConfig: HermesConfigRecord = { display: { language: 'en', skin: 'slate' } }
+
     const configClient: I18nConfigClient = {
       getConfig: vi.fn().mockResolvedValue(latestConfig),
       saveConfig
diff --git a/apps/desktop/src/components/language-switcher.tsx b/apps/desktop/src/components/language-switcher.tsx
index 59edb622ef1..a95c361d485 100644
--- a/apps/desktop/src/components/language-switcher.tsx
+++ b/apps/desktop/src/components/language-switcher.tsx
@@ -1,8 +1,8 @@
 import { useState } from 'react'
 
 import { Button } from '@/components/ui/button'
+import { Command, CommandInput, CommandItem, CommandList } from '@/components/ui/command'
 import { Popover, PopoverContent, PopoverTrigger } from '@/components/ui/popover'
-import { ScrollArea } from '@/components/ui/scroll-area'
 import { Sheet, SheetContent, SheetDescription, SheetHeader, SheetTitle, SheetTrigger } from '@/components/ui/sheet'
 import { useIsMobile } from '@/hooks/use-mobile'
 import { type Locale, LOCALE_META, useI18n } from '@/i18n'
@@ -17,12 +17,14 @@ export interface LanguageSwitcherProps {
   dropUp?: boolean
 }
 
-interface LanguageSwitcherOptionsProps {
+interface LanguageCommandProps {
   allLocales: Array<[Locale, (typeof LOCALE_META)[Locale]]>
+  autoFocus?: boolean
   disabled?: boolean
-  label: string
   locale: Locale
+  noResults: string
   onSelect: (code: Locale) => void
+  searchPlaceholder: string
 }
 
 export function LanguageSwitcher({ className, collapsed = false, dropUp = false }: LanguageSwitcherProps) {
@@ -37,6 +39,7 @@ export function LanguageSwitcher({ className, collapsed = false, dropUp = false
   const selectLocale = async (code: Locale) => {
     if (code === locale || isSavingLocale) {
       setOpen(false)
+
       return
     }
 
@@ -53,8 +56,8 @@ export function LanguageSwitcher({ className, collapsed = false, dropUp = false
 
   const trigger = (
     <Button
-      aria-label={title}
       aria-expanded={open}
+      aria-label={title}
       className={cn(
         'min-w-32 justify-between gap-2 border-(--ui-stroke-tertiary) bg-(--ui-bg-quinary) px-2.5 text-left text-muted-foreground hover:text-foreground',
         collapsed && 'min-w-0 px-2',
@@ -68,7 +71,7 @@ export function LanguageSwitcher({ className, collapsed = false, dropUp = false
     >
       <span className="inline-flex min-w-0 items-center gap-2">
         <Globe className="size-3.5 shrink-0" />
-        {!collapsed && <span className="truncate">{locale === 'en' ? 'EN' : current.name}</span>}
+        {!collapsed && <span className="truncate">{current.name}</span>}
       </span>
       {!collapsed && <ChevronDown className="size-3 shrink-0 opacity-70" />}
     </Button>
@@ -83,15 +86,14 @@ export function LanguageSwitcher({ className, collapsed = false, dropUp = false
             <SheetTitle>{title}</SheetTitle>
             <SheetDescription>{t.language.description}</SheetDescription>
           </SheetHeader>
-          <ScrollArea className="max-h-80 px-2 pb-3">
-            <LanguageSwitcherOptions
-              allLocales={allLocales}
-              disabled={isSavingLocale}
-              label={title}
-              locale={locale}
-              onSelect={code => void selectLocale(code)}
-            />
-          </ScrollArea>
+          <LanguageCommand
+            allLocales={allLocales}
+            disabled={isSavingLocale}
+            locale={locale}
+            noResults={t.language.noResults}
+            onSelect={code => void selectLocale(code)}
+            searchPlaceholder={t.language.searchPlaceholder}
+          />
         </SheetContent>
       </Sheet>
     )
@@ -100,46 +102,74 @@ export function LanguageSwitcher({ className, collapsed = false, dropUp = false
   return (
     <Popover onOpenChange={setOpen} open={open}>
       <PopoverTrigger asChild>{trigger}</PopoverTrigger>
-      <PopoverContent align="end" className="w-48 p-1" side={dropUp ? 'top' : 'bottom'}>
-        <ScrollArea className="max-h-80">
-          <LanguageSwitcherOptions
-            allLocales={allLocales}
-            disabled={isSavingLocale}
-            label={title}
-            locale={locale}
-            onSelect={code => void selectLocale(code)}
-          />
-        </ScrollArea>
+      <PopoverContent align="end" className="w-56 p-0" side={dropUp ? 'top' : 'bottom'}>
+        <LanguageCommand
+          allLocales={allLocales}
+          autoFocus
+          disabled={isSavingLocale}
+          locale={locale}
+          noResults={t.language.noResults}
+          onSelect={code => void selectLocale(code)}
+          searchPlaceholder={t.language.searchPlaceholder}
+        />
       </PopoverContent>
     </Popover>
   )
 }
 
-function LanguageSwitcherOptions({ allLocales, disabled, label, locale, onSelect }: LanguageSwitcherOptionsProps) {
-  return (
-    <div aria-label={label} className="py-1" role="listbox">
-      {allLocales.map(([code, meta]) => {
-        const selected = code === locale
+function LanguageCommand({
+  allLocales,
+  autoFocus,
+  disabled,
+  locale,
+  noResults,
+  onSelect,
+  searchPlaceholder
+}: LanguageCommandProps) {
+  const [search, setSearch] = useState('')
 
-        return (
-          <button
-            aria-selected={selected}
-            className={cn(
-              'flex w-full cursor-pointer items-center gap-2 rounded-md px-2.5 py-1.5 text-left text-[length:var(--conversation-caption-font-size)] transition-colors hover:bg-(--chrome-action-hover) hover:text-foreground disabled:pointer-events-none disabled:opacity-50',
-              selected ? 'font-medium text-foreground' : 'text-muted-foreground'
-            )}
-            disabled={disabled}
-            key={code}
-            onClick={() => onSelect(code)}
-            role="option"
-            type="button"
-          >
-            <span className="min-w-0 flex-1 truncate">{meta.name}</span>
-            <span className="font-mono text-[0.65rem] uppercase text-(--ui-text-tertiary)">{code}</span>
-            {selected && <Check className="size-3.5 shrink-0 text-primary" />}
-          </button>
-        )
-      })}
-    </div>
+  // Own the search term and filter manually. cmdk's built-in shouldFilter
+  // reorders items by its fuzzy-match score (≈alphabetical with an empty
+  // query), which destroys the curated en→zh→zh-hant→ja order. We disable it
+  // and do a plain substring filter that preserves array order — matching
+  // model-picker.tsx. Match against the endonym, the (hidden) English name,
+  // and the locale code so "日本"/"japanese"/"ja" all find Japanese.
+  const q = search.trim().toLowerCase()
+
+  const filtered = allLocales.filter(
+    ([code, meta]) =>
+      !q ||
+      meta.name.toLowerCase().includes(q) ||
+      meta.englishName.toLowerCase().includes(q) ||
+      code.toLowerCase().includes(q)
+  )
+
+  return (
+    <Command className="bg-transparent" shouldFilter={false}>
+      <CommandInput autoFocus={autoFocus} onValueChange={setSearch} placeholder={searchPlaceholder} value={search} />
+      <CommandList className="max-h-80 p-1">
+        {filtered.length === 0 ? (
+          <div className="py-6 text-center text-sm text-muted-foreground">{noResults}</div>
+        ) : (
+          filtered.map(([code, meta]) => {
+            const selected = code === locale
+
+            return (
+              <CommandItem
+                className={cn(selected ? 'font-medium text-foreground' : 'text-muted-foreground')}
+                disabled={disabled}
+                key={code}
+                onSelect={() => onSelect(code)}
+                value={code}
+              >
+                <Check className={cn('size-3.5 shrink-0 text-primary', !selected && 'invisible')} />
+                <span className="min-w-0 flex-1 truncate">{meta.name}</span>
+                <span className="font-mono text-[0.65rem] uppercase text-(--ui-text-tertiary)">{code}</span>
+              </CommandItem>
+            )
+          })
+        )}
+      </CommandList>
+    </Command>
   )
 }
diff --git a/apps/desktop/src/i18n/en.ts b/apps/desktop/src/i18n/en.ts
index 17c42e2d365..8f99e8cdac5 100644
--- a/apps/desktop/src/i18n/en.ts
+++ b/apps/desktop/src/i18n/en.ts
@@ -132,7 +132,9 @@ export const en: Translations = {
     description: 'Choose the language for the desktop interface.',
     saving: 'Saving language…',
     saveError: 'Language update failed',
-    switchTo: 'Switch language'
+    switchTo: 'Switch language',
+    searchPlaceholder: 'Search languages…',
+    noResults: 'No languages found'
   },
 
   settings: {
diff --git a/apps/desktop/src/i18n/ja.ts b/apps/desktop/src/i18n/ja.ts
index 3c93dd39555..93177c380cf 100644
--- a/apps/desktop/src/i18n/ja.ts
+++ b/apps/desktop/src/i18n/ja.ts
@@ -21,7 +21,9 @@ export const ja = defineLocale({
     description: 'デスクトップインターフェイスの言語を選択します。',
     saving: '言語を保存中…',
     saveError: '言語の更新に失敗しました',
-    switchTo: '言語を切り替え'
+    switchTo: '言語を切り替え',
+    searchPlaceholder: '言語を検索…',
+    noResults: '言語が見つかりません'
   },
 
   settings: {
diff --git a/apps/desktop/src/i18n/languages.ts b/apps/desktop/src/i18n/languages.ts
index 2694b3ba5c3..5b4990f4970 100644
--- a/apps/desktop/src/i18n/languages.ts
+++ b/apps/desktop/src/i18n/languages.ts
@@ -6,31 +6,36 @@ export const LOCALE_OPTIONS = [
   {
     id: 'en',
     name: 'English',
+    englishName: 'English',
     configValue: 'en'
   },
   {
     id: 'zh',
     name: '简体中文',
+    englishName: 'Simplified Chinese',
     configValue: 'zh'
   },
   {
     id: 'zh-hant',
     name: '繁體中文',
+    englishName: 'Traditional Chinese',
     configValue: 'zh-hant'
   },
   {
     id: 'ja',
     name: '日本語',
+    englishName: 'Japanese',
     configValue: 'ja'
   }
-] as const satisfies readonly { configValue: string; id: Locale; name: string }[]
+] as const satisfies readonly { configValue: string; englishName: string; id: Locale; name: string }[]
 
-// Endonyms (native names) for the language picker so users recognize their
-// language regardless of the current UI language. No country flags:
-// languages are not countries.
-export const LOCALE_META: Record<Locale, { name: string }> = Object.fromEntries(
-  LOCALE_OPTIONS.map(locale => [locale.id, { name: locale.name }])
-) as Record<Locale, { name: string }>
+// `name` is the endonym (native name) shown in the picker so users recognize
+// their language regardless of the current UI language. No country flags:
+// languages are not countries. `englishName` is search-only (not shown) so an
+// English speaker can type "japanese"/"traditional" to filter the list.
+export const LOCALE_META: Record<Locale, { name: string; englishName: string }> = Object.fromEntries(
+  LOCALE_OPTIONS.map(locale => [locale.id, { name: locale.name, englishName: locale.englishName }])
+) as Record<Locale, { name: string; englishName: string }>
 
 const LOCALE_ALIASES: Record<string, Locale> = {
   en: 'en',
diff --git a/apps/desktop/src/i18n/types.ts b/apps/desktop/src/i18n/types.ts
index 6e7da1cbddc..7e794fc900d 100644
--- a/apps/desktop/src/i18n/types.ts
+++ b/apps/desktop/src/i18n/types.ts
@@ -144,6 +144,8 @@ export interface Translations {
     saving: string
     saveError: string
     switchTo: string
+    searchPlaceholder: string
+    noResults: string
   }
 
   settings: {
diff --git a/apps/desktop/src/i18n/zh-hant.ts b/apps/desktop/src/i18n/zh-hant.ts
index fbfc0124312..d6d1b8c8b12 100644
--- a/apps/desktop/src/i18n/zh-hant.ts
+++ b/apps/desktop/src/i18n/zh-hant.ts
@@ -21,7 +21,9 @@ export const zhHant = defineLocale({
     description: '選擇桌面介面的語言。',
     saving: '正在儲存語言…',
     saveError: '語言更新失敗',
-    switchTo: '切換語言'
+    switchTo: '切換語言',
+    searchPlaceholder: '搜尋語言…',
+    noResults: '找不到語言'
   },
 
   settings: {
diff --git a/apps/desktop/src/i18n/zh.ts b/apps/desktop/src/i18n/zh.ts
index 3cdc6a01870..f9546491c1e 100644
--- a/apps/desktop/src/i18n/zh.ts
+++ b/apps/desktop/src/i18n/zh.ts
@@ -128,7 +128,9 @@ export const zh: Translations = {
     description: '选择桌面界面的语言。',
     saving: '正在保存语言…',
     saveError: '语言更新失败',
-    switchTo: '切换语言'
+    switchTo: '切换语言',
+    searchPlaceholder: '搜索语言…',
+    noResults: '未找到语言'
   },
 
   settings: {