# Default Language Setting Implementation Plan > **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking. **Goal:** Allow admin to configure a global default language in System Settings, which is forced for unauthenticated users and logged-in users without a personal language preference. **Architecture:** Backend adds a `DefaultLanguage` option to the existing flat-key option system (same pattern as `SystemName`, `ServerAddress`). The value flows to frontend via `/api/status`. Frontend applies it in two places: `PageLayout.jsx` (for unauthenticated users) and `UserContext` (for logged-in users without preference). **Tech Stack:** Go (backend), React + Semi UI (frontend), i18next (i18n) **Spec:** `docs/superpowers/specs/2026-04-17-default-language-setting-design.md` --- ## File Map | File | Action | Responsibility | |------|--------|---------------| | `common/constants.go` | Modify | Declare `DefaultLanguage` variable | | `model/option.go` | Modify | Handle `DefaultLanguage` in option update switch | | `controller/misc.go` | Modify | Expose `default_language` in `/api/status` response | | `web/src/components/settings/SystemSetting.jsx` | Modify | Admin UI: language dropdown in system settings | | `web/src/components/layout/PageLayout.jsx` | Modify | Apply default language for unauthenticated users | | `web/src/context/User/index.jsx` | Modify | Fall back to default language when user has no preference | --- ### Task 1: Backend — Add DefaultLanguage variable and option handling **Files:** - Modify: `common/constants.go:17-18` (after `TopUpLink` declaration) - Modify: `model/option.go:457-458` (after `Logo` case in `updateOptionMap` switch) - [ ] **Step 1: Add `DefaultLanguage` variable to `common/constants.go`** In `common/constants.go`, after line 18 (`var TopUpLink = ""`), add: ```go var DefaultLanguage = "" // admin-configured default language; empty = follow browser detection ``` - [ ] **Step 2: Add case handler in `model/option.go`** In `model/option.go`, after the `case "Logo":` block (line 457-458), add: ```go case "DefaultLanguage": common.DefaultLanguage = value ``` - [ ] **Step 3: Verify the Go code compiles** Run: `go build ./...` Expected: no errors - [ ] **Step 4: Commit** ```bash git add common/constants.go model/option.go git commit -m "feat(default-language): add DefaultLanguage variable and option handler" ``` --- ### Task 2: Backend — Expose default_language in /api/status **Files:** - Modify: `controller/misc.go:89` (after `"default_use_auto_group"` line) - [ ] **Step 1: Add `default_language` field to GetStatus response** In `controller/misc.go`, inside `GetStatus()`, after the line containing `"default_use_auto_group": setting.DefaultUseAutoGroup,` (line 89), add: ```go "default_language": common.DefaultLanguage, ``` Place it right before the blank line at line 90, aligned with the surrounding entries. - [ ] **Step 2: Verify the Go code compiles** Run: `go build ./...` Expected: no errors - [ ] **Step 3: Commit** ```bash git add controller/misc.go git commit -m "feat(default-language): expose default_language in /api/status response" ``` --- ### Task 3: Frontend — Add DefaultLanguage dropdown in System Settings **Files:** - Modify: `web/src/components/settings/SystemSetting.jsx` - [ ] **Step 1: Add `DefaultLanguage` to `inputs` state** In `web/src/components/settings/SystemSetting.jsx`, in the `inputs` useState (around line 49-112), add `DefaultLanguage: ''` after `ServerAddress: ''` (line 102): ```javascript ServerAddress: '', DefaultLanguage: '', ``` - [ ] **Step 2: Add `submitDefaultLanguage` function** After `submitServerAddress` (line 315-318), add a new function: ```javascript const submitDefaultLanguage = async () => { await updateOptions([{ key: 'DefaultLanguage', value: inputs.DefaultLanguage || '' }]); }; ``` - [ ] **Step 3: Add language dropdown UI in the 通用设置 Card** In the `通用设置` `Form.Section` (line 715-733), inside the `` block, after the `ServerAddress` `` closing tag (line 728) and before the `` closing tag (line 729), add a new ``: ```jsx ``` Also change the `ServerAddress` Col from `md={24} lg={24} xl={24}` to `md={24} lg={12} xl={12}` so both fields sit side by side on large screens. - [ ] **Step 4: Add save button for DefaultLanguage** After the existing `submitServerAddress` button (line 730-732), add: ```jsx ``` - [ ] **Step 5: Verify frontend compiles** Run: `cd web && bun run build` Expected: build succeeds - [ ] **Step 6: Commit** ```bash git add web/src/components/settings/SystemSetting.jsx git commit -m "feat(default-language): add language dropdown in system settings" ``` --- ### Task 4: Frontend — Apply default language for unauthenticated users **Files:** - Modify: `web/src/components/layout/PageLayout.jsx:87-100` (loadStatus function) - [ ] **Step 1: Modify `loadStatus` to apply default language** In `web/src/components/layout/PageLayout.jsx`, in the `loadStatus` function (line 87-100), after `setStatusData(data)` (line 93) and before the `} else {` (line 94), add: ```javascript // Apply admin-configured default language for unauthenticated users if (data.default_language && !localStorage.getItem('user')) { i18n.changeLanguage(data.default_language); } ``` - [ ] **Step 2: Update the existing localStorage language fallback logic** In the same file, the existing `useEffect` (line 102-120) reads `localStorage.getItem('i18nextLng')` and calls `i18n.changeLanguage(savedLang)`. This logic should be kept as-is — it handles the case where `default_language` is not set (admin chose "auto"). No changes needed to this block. - [ ] **Step 3: Verify frontend compiles** Run: `cd web && bun run build` Expected: build succeeds - [ ] **Step 4: Commit** ```bash git add web/src/components/layout/PageLayout.jsx git commit -m "feat(default-language): apply default language for unauthenticated users" ``` --- ### Task 5: Frontend — Fall back to default language for logged-in users without preference **Files:** - Modify: `web/src/context/User/index.jsx:20-45` - [ ] **Step 1: Import StatusContext** At the top of `web/src/context/User/index.jsx`, add `StatusContext` import after the existing imports: ```javascript import { StatusContext } from '../Status'; ``` - [ ] **Step 2: Access StatusContext inside UserProvider** Inside `UserProvider` (line 29), before the `useEffect`, add: ```javascript const [statusState] = React.useContext(StatusContext); ``` - [ ] **Step 3: Update language sync logic** Replace the existing `useEffect` (lines 34-45) with: ```javascript // Sync language preference when user data is loaded useEffect(() => { if (state.user?.setting) { try { const settings = JSON.parse(state.user.setting); if (settings.language && settings.language !== i18n.language) { i18n.changeLanguage(settings.language); } else if (!settings.language && statusState.status?.default_language) { // No personal preference — fall back to admin default i18n.changeLanguage(statusState.status.default_language); } } catch (e) { // Ignore parse errors } } }, [state.user?.setting, statusState.status?.default_language, i18n]); ``` - [ ] **Step 4: Verify frontend compiles** Run: `cd web && bun run build` Expected: build succeeds - [ ] **Step 5: Commit** ```bash git add web/src/context/User/index.jsx git commit -m "feat(default-language): fall back to default language for users without preference" ``` --- ### Task 6: Integration verification - [ ] **Step 1: Start full-stack dev server** Terminal 1: `cd web && bun run dev` Terminal 2: `go run main.go` - [ ] **Step 2: Test admin setting** 1. Login as admin, navigate to Settings → System Settings (系统设置) 2. Find the "默认语言" dropdown in the 通用设置 section 3. Select "English" and click "保存默认语言" 4. Verify success toast appears 5. Refresh the page — the dropdown should still show "English" - [ ] **Step 3: Test unauthenticated user behavior** 1. Open an incognito/private browser window 2. Visit the site 3. Expected: The page renders in English (not following browser language) 4. The header language selector still shows English as active - [ ] **Step 4: Test logged-in user with personal preference** 1. Login as a regular user 2. Go to personal settings, set language to "Français" 3. Refresh — page should be in French (personal preference overrides admin default) - [ ] **Step 5: Test logged-in user without personal preference** 1. Login as a user who has never set a language preference 2. Expected: Page renders in English (admin default), not browser language - [ ] **Step 6: Test "auto" mode** 1. As admin, set "默认语言" back to "自动(跟随浏览器)" 2. Save, then test in incognito — should follow browser language again - [ ] **Step 7: Verify /api/status returns the field** ```bash curl -s http://localhost:3000/api/status | python -m json.tool | grep default_language ``` Expected: `"default_language": "en"` (or the set value, or `""` if auto)