多语言支持

/zh-CN/dashboard    # 简体中文界面
/en/dashboard       # 英文界面
/ja/settings        # 日文设置页

// messages/zh-CN/index.ts
import auth from "./auth.json";
import common from "./common.json";
import dashboard from "./dashboard.json";
// ... 其他导入

export default {
  auth,
  common,
  dashboard,
  // ... 其他命名空间
};

messages/zh-CN/settings/
├── index.ts           # 聚合所有子模块
├── nav.json           # 导航菜单
├── common.json        # 通用设置
├── config.json        # 配置项
├── providers/         # 供应商相关
│   ├── autoSort.json
│   ├── batchEdit.json
│   └── form/          # 表单相关
│       ├── apiTest.json
│       └── buttons.json

// src/i18n/config.ts
export const locales = ["zh-CN", "zh-TW", "en", "ru", "ja"] as const;
export type Locale = (typeof locales)[number];
export const defaultLocale: Locale = "zh-CN";

export const localeLabels: Record<Locale, string> = {
  "zh-CN": "简体中文",
  "zh-TW": "繁体中文",
  en: "English",
  ru: "Русский",
  ja: "日本語",
};

// src/i18n/routing.ts
import { createNavigation } from "next-intl/navigation";
import { defineRouting } from "next-intl/routing";

export const routing = defineRouting({
  locales,
  defaultLocale,
  localePrefix: "always",
  localeCookie: {
    name: "NEXT_LOCALE",
    maxAge: 365 * 24 * 60 * 60,  // 1年
    path: "/",
    sameSite: "lax",
  },
});

// 类型安全的导航工具
export const { Link, redirect, useRouter, usePathname } = createNavigation(routing);

// src/i18n/request.ts
import { getRequestConfig } from "next-intl/server";

export default getRequestConfig(async ({ requestLocale }) => {
  let locale = await requestLocale;

  // 验证语言有效性
  if (!locale || !routing.locales.includes(locale as Locale)) {
    locale = routing.defaultLocale;
  }

  // 动态导入当前语言的翻译文件
  const messages = await import(`../../messages/${locale}`)
    .then((module) => module.default);

  const timeZone = await resolveSystemTimezone();

  return {
    locale,
    messages,
    timeZone,
    now: new Date(),
    getMessageFallback: ({ namespace, key }) => `${namespace}.${key}`,
  };
});

import { useTranslations } from "next-intl";

export default function DashboardPage() {
  const t = useTranslations("dashboard");

  return (
    <div>
      <h1>{t("title")}</h1>
      <p>{t("welcomeMessage")}</p>
    </div>
  );
}

"use client";

import { useTranslations } from "next-intl";
import { Link } from "@/i18n/routing";

export function UserCard() {
  const t = useTranslations("users");

  return (
    <div>
      <h2>{t("cardTitle")}</h2>
      <Link href="/users/profile">
        {t("viewProfile")}
      </Link>
    </div>
  );
}

"use server";

import { getTranslations } from "next-intl/server";

export async function createUser(data: UserData) {
  const t = await getTranslations("errors");

  if (!data.name) {
    return { error: t("REQUIRED_FIELD", { field: "用户名" }) };
  }

  // ... 业务逻辑
}

import { LanguageSwitcher } from "@/components/ui/language-switcher";

// 在布局或导航栏中使用
<LanguageSwitcher size="sm" />

// src/lib/utils/error-messages.ts
export const ERROR_CODES = {
  UNAUTHORIZED: "UNAUTHORIZED",
  PERMISSION_DENIED: "PERMISSION_DENIED",
  RATE_LIMIT_RPM_EXCEEDED: "RATE_LIMIT_RPM_EXCEEDED",
  // ... 更多错误码
} as const;

// 在翻译文件中使用占位符
{
  "RATE_LIMIT_RPM_EXCEEDED": "请求频率超限：当前 {current} 次/分钟（限制：{limit} 次/分钟）"
}

// 使用示例
const message = t("RATE_LIMIT_RPM_EXCEEDED", {
  current: 120,
  limit: 100,
});
// 结果："请求频率超限：当前 120 次/分钟（限制：100 次/分钟）"

// 时区解析优先级：
// 1. 数据库 system_settings.timezone
// 2. 环境变量 TZ
// 3. 回退到 UTC

const timeZone = await resolveSystemTimezone();
// 返回如 "Asia/Shanghai", "America/New_York" 等 IANA 时区标识符

if (!locale || !routing.locales.includes(locale as Locale)) {
  locale = routing.defaultLocale;
}

getMessageFallback: ({ namespace, key }) => {
  return `${namespace}.${key}`;
}
// 显示如 "errors.UNKNOWN_ERROR"

// 创建稳定的 now 时间戳
const now = new Date();

<NextIntlClientProvider messages={messages} timeZone={timeZone} now={now}>
  {children}
</NextIntlClientProvider>

const locale = isLocaleInPath ? potentialLocale : routing.defaultLocale;
url.pathname = `/${locale}/login`;
url.searchParams.set("from", pathWithoutLocale);
return NextResponse.redirect(url);