---
import { pathHasLocale, getRelativeLocaleUrl } from 'astro:i18n';

// 使用 pathHasLocale 安全判断当前路径是否已包含任何语言前缀（返回 boolean）
const hasLocale = pathHasLocale(Astro.url.pathname);

// 自动生成中文根路径
const cnRootUrl = getRelativeLocaleUrl('cn', '');
---

<script is:inline define:vars={{ hasLocale, cnRootUrl }}>
  (() => {
    try {
      // 当前路径已带有语言前缀（如 /cn/ 或 /en/），直接跳过
      if (hasLocale) return;

      // 避免重复跳转
      if (sessionStorage.getItem('lang-redirect')) return;

      // 判定浏览器偏好语言
      const langs = navigator.languages || [navigator.language || 'en'];
      const isZh = langs.some((l) => l.toLowerCase().startsWith('zh'));

      if (!isZh) return;

      sessionStorage.setItem('lang-redirect', '1');

      // 拼接真实跳转路径
      const { pathname, search, hash } = location;
      const cleanPath = pathname === '/' ? '' : pathname;
      const targetUrl = `${cnRootUrl}${cleanPath.replace(/^\//, '')}${search}${hash}`;

      location.replace(targetUrl);
    } catch (e) {}
  })();
</script>