feat: Make i18n languages fully configurable via docs.site.json

README.md

@@ -13,8 +13,10 @@ This repository contains the documentation for:
 ## Features
 
 - 🌍 **Multi-language Support**: 
-  - Source: English (`content/docs/*.mdx`)
-  - Target: Chinese (`content/docs/*.cn.mdx`) - *Auto-translated via AI using dot parser*
+  - Configurable via `docs.site.json`
+  - Built-in support for: English, Chinese, Japanese, French, German, Spanish
+  - Extensible: Easy to add new languages
+  - Auto-translation via AI CLI using dot parser convention
 - 📝 **MDX Content**: Interactive documentation with Type-safe components.
 - 🛠️ **Automated Workflows**: 
   - AI Translation CLI (`packages/cli`)
@@ -76,12 +78,43 @@ The guide covers:
 
 ### Internationalization (i18n)
 
-The default language is configured in `lib/i18n.ts` as `en`. If you change the default language, you must also update the redirect destination in `vercel.json` to match (currently `/en/docs`).
+Language configuration is managed in `content/docs.site.json`:
+
+```json
+{
+  "i18n": {
+    "enabled": true,
+    "defaultLanguage": "en",
+    "languages": ["en", "cn"]
+  }
+}
+```
+
+**Configurable Options:**
+- `enabled`: Enable/disable i18n support
+- `defaultLanguage`: The default language for the site (e.g., "en")
+- `languages`: Array of supported language codes (e.g., ["en", "cn", "ja", "fr"])
+
+**Supported Languages:**
+The system includes built-in UI translations for:
+- `en` - English
+- `cn` - Chinese (Simplified) / 简体中文
+- `ja` - Japanese / 日本語
+- `fr` - French / Français
+- `de` - German / Deutsch
+- `es` - Spanish / Español
+
+To add a new language:
+1. Add the language code to the `languages` array in `docs.site.json`
+2. If UI translations don't exist, add them to `packages/site/lib/translations.ts`
+3. Create content files with the language suffix (e.g., `file.{lang}.mdx`)
+
+**Important:** If you change the default language, you must also update the redirect destination in `vercel.json` to match (currently `/en/docs`).
 
 ### Content Structure
 
-Content files are located in `content/docs/` and use language suffixes:
-- `{filename}.en.mdx` - English content
-- `{filename}.cn.mdx` - Chinese content
-- `meta.en.json` - English navigation
-- `meta.cn.json` - Chinese navigation
+Content files are located in `content/docs/` and use language suffixes based on the `languages` configuration:
+- `{filename}.{lang}.mdx` - Language-specific content (e.g., `index.en.mdx`, `index.cn.mdx`)
+- `meta.{lang}.json` - Language-specific navigation (e.g., `meta.en.json`, `meta.cn.json`)
+
+The CLI translate utility automatically generates language suffixes based on your configuration.

packages/cli/src/commands/translate.mjs

@@ -1,7 +1,7 @@
 import fs from 'node:fs';
 import path from 'node:path';
 import OpenAI from 'openai';
-import { getAllMdxFiles, resolveTranslatedFilePath, translateContent } from '../utils/translate.mjs';
+import { getAllMdxFiles, resolveTranslatedFilePath, translateContent, getSiteConfig } from '../utils/translate.mjs';
 
 export function registerTranslateCommand(cli) {
   cli
@@ -22,6 +22,11 @@ export function registerTranslateCommand(cli) {
         baseURL: OPENAI_BASE_URL,
       });
 
+      // Get language configuration
+      const config = getSiteConfig();
+      console.log(`Translation target: ${config.defaultLanguage} -> ${config.targetLanguage}`);
+      console.log(`Configured languages: ${config.languages.join(', ')}\n`);
+
       let targetFiles = [];
 
       if (options.all) {

packages/cli/src/utils/translate.mjs

@@ -2,9 +2,60 @@ import fs from 'node:fs';
 import path from 'node:path';
 import OpenAI from 'openai';
 
-// Supported language suffixes for i18n
-const LANGUAGE_SUFFIXES = ['.cn.mdx', '.en.mdx'];
-const TARGET_LANGUAGE_SUFFIX = '.cn.mdx';
+/**
+ * Load site configuration from docs.site.json
+ * @returns {object} - The site configuration
+ */
+function loadSiteConfig() {
+  const configPath = path.resolve(process.cwd(), 'content/docs.site.json');
+
+  if (!fs.existsSync(configPath)) {
+    console.warn(`Warning: docs.site.json not found at ${configPath}, using defaults`);
+    // Fallback matches the default configuration in packages/site/lib/site-config.ts
+    return {
+      i18n: {
+        enabled: true,
+        defaultLanguage: 'en',
+        languages: ['en', 'cn']
+      }
+    };
+  }
+
+  try {
+    const configContent = fs.readFileSync(configPath, 'utf-8');
+    return JSON.parse(configContent);
+  } catch (error) {
+    console.error('Error loading docs.site.json:', error);
+    throw error;
+  }
+}
+
+// Load configuration
+const siteConfig = loadSiteConfig();
+const languages = siteConfig.i18n?.languages || ['en', 'cn'];
+const defaultLanguage = siteConfig.i18n?.defaultLanguage || 'en';
+
+// Generate language suffixes dynamically from config
+// e.g., ['en', 'cn'] -> ['.en.mdx', '.cn.mdx']
+const LANGUAGE_SUFFIXES = languages.map(lang => `.${lang}.mdx`);
+
+// Target language is the first non-default language
+const targetLanguage = languages.find(lang => lang !== defaultLanguage) || languages[0];
+const TARGET_LANGUAGE_SUFFIX = `.${targetLanguage}.mdx`;
+
+/**
+ * Get the current site configuration
+ * @returns {object} - Configuration object with languages info
+ */
+export function getSiteConfig() {
+  return {
+    languages,
+    defaultLanguage,
+    targetLanguage,
+    languageSuffixes: LANGUAGE_SUFFIXES,
+    targetLanguageSuffix: TARGET_LANGUAGE_SUFFIX,
+  };
+}
 
 /**
  * Check if a file has a language suffix
@@ -37,7 +88,8 @@ export function getAllMdxFiles(dir) {
 
 export function resolveTranslatedFilePath(enFilePath) {
   // Strategy: Use dot parser convention
-  // content/docs/path/to/file.mdx -> content/docs/path/to/file.cn.mdx
+  // content/docs/path/to/file.mdx -> content/docs/path/to/file.{targetLang}.mdx
+  // Target language is determined from docs.site.json configuration
   // Skip files that already have language suffix
   const absPath = path.resolve(enFilePath);
 

packages/site/app/[lang]/layout.tsx

@@ -2,24 +2,11 @@ import 'fumadocs-ui/style.css';
 import { RootProvider } from 'fumadocs-ui/provider/next';
 import { defineI18nUI } from 'fumadocs-ui/i18n';
 import { i18n } from '@/lib/i18n';
+import { getTranslations } from '@/lib/translations';
 
 
 const { provider } = defineI18nUI(i18n, {
-  translations: {
-    en: {
-      displayName: 'English',
-    },
-    cn: {
-      displayName: '简体中文',
-      toc: '目录',
-      search: '搜索文档',
-      lastUpdate: '最后更新于',
-      searchNoResult: '没有结果',
-      previousPage: '上一页',
-      nextPage: '下一页',
-      chooseLanguage: '选择语言',
-    },
-  },
+  translations: getTranslations(),
 });
 
 export default async function Layout({ params, children }: LayoutProps<'/[lang]'>) {

packages/site/app/layout.tsx

@@ -2,17 +2,11 @@ import 'fumadocs-ui/style.css';
 import { RootProvider } from 'fumadocs-ui/provider/next';
 import { defineI18nUI } from 'fumadocs-ui/i18n';
 import { i18n } from '@/lib/i18n';
+import { getTranslations } from '@/lib/translations';
 
 
 const { provider } = defineI18nUI(i18n, {
-  translations: {
-    en: {
-      displayName: 'English',
-    },
-    cn: {
-      displayName: 'Chinese', 
-    },
-  },
+  translations: getTranslations(),
 });
 
 export default function Layout({ children }: { children: React.ReactNode }) {

packages/site/lib/translations.ts

@@ -0,0 +1,102 @@
+import { siteConfig } from './site-config';
+
+/**
+ * Translation strings for different languages
+ * These are the UI strings used by fumadocs-ui
+ */
+interface LanguageTranslations {
+  displayName: string;
+  toc?: string;
+  search?: string;
+  lastUpdate?: string;
+  searchNoResult?: string;
+  previousPage?: string;
+  nextPage?: string;
+  chooseLanguage?: string;
+}
+
+/**
+ * Default translations for supported languages
+ * Add new language translations here as needed
+ */
+const defaultTranslations: Record<string, LanguageTranslations> = {
+  en: {
+    displayName: 'English',
+  },
+  cn: {
+    displayName: '简体中文',
+    toc: '目录',
+    search: '搜索文档',
+    lastUpdate: '最后更新于',
+    searchNoResult: '没有结果',
+    previousPage: '上一页',
+    nextPage: '下一页',
+    chooseLanguage: '选择语言',
+  },
+  ja: {
+    displayName: '日本語',
+    toc: '目次',
+    search: 'ドキュメントを検索',
+    lastUpdate: '最終更新',
+    searchNoResult: '結果がありません',
+    previousPage: '前のページ',
+    nextPage: '次のページ',
+    chooseLanguage: '言語を選択',
+  },
+  fr: {
+    displayName: 'Français',
+    toc: 'Table des matières',
+    search: 'Rechercher dans la documentation',
+    lastUpdate: 'Dernière mise à jour',
+    searchNoResult: 'Aucun résultat',
+    previousPage: 'Page précédente',
+    nextPage: 'Page suivante',
+    chooseLanguage: 'Choisir la langue',
+  },
+  de: {
+    displayName: 'Deutsch',
+    toc: 'Inhaltsverzeichnis',
+    search: 'Dokumentation durchsuchen',
+    lastUpdate: 'Zuletzt aktualisiert',
+    searchNoResult: 'Keine Ergebnisse',
+    previousPage: 'Vorherige Seite',
+    nextPage: 'Nächste Seite',
+    chooseLanguage: 'Sprache wählen',
+  },
+  es: {
+    displayName: 'Español',
+    toc: 'Tabla de contenidos',
+    search: 'Buscar documentación',
+    lastUpdate: 'Última actualización',
+    searchNoResult: 'Sin resultados',
+    previousPage: 'Página anterior',
+    nextPage: 'Página siguiente',
+    chooseLanguage: 'Elegir idioma',
+  },
+};
+
+/**
+ * Get translations for configured languages
+ * Returns only the translations for languages specified in docs.site.json
+ */
+export function getTranslations(): Record<string, LanguageTranslations> {
+  const configuredLanguages = siteConfig.i18n.languages;
+  const translations: Record<string, LanguageTranslations> = {};
+
+  for (const lang of configuredLanguages) {
+    if (defaultTranslations[lang]) {
+      translations[lang] = defaultTranslations[lang];
+    } else {
+      // If no translation exists for a configured language, provide a minimal fallback
+      // Only log warning in development
+      if (process.env.NODE_ENV === 'development') {
+        console.warn(`Warning: No translations found for language "${lang}". Using minimal fallback.`);
+      }
+      translations[lang] = {
+        displayName: lang.toUpperCase(),
+      };
+    }
+  }
+
+  return translations;
+}