/* 静态预渲染：把 LandingPage 渲染为静态 HTML 注入 dist/index.html 的 #root，
   让 Google / Bing / ChatGPT / Perplexity 等不执行 JS 的爬虫也能读到真实正文。
   同时生成 robots.txt 与 sitemap.xml。 */
const esbuild = require('esbuild');
const React = require('react');
const ReactDOMServer = require('react-dom/server');
const fs = require('fs');
const path = require('path');

const FRONT = '/app/frontend';
const OUT = path.join(FRONT, 'dist');

// 1) 用 esbuild 把组件打包成 CJS（react/react-dom/react-router-dom 保持 external，复用运行时同一实例）
esbuild.buildSync({
  entryPoints: [path.join(FRONT, 'prerender-entry.tsx')],
  bundle: true,
  format: 'cjs',
  platform: 'node',
  outfile: path.join(FRONT, 'prerender-bundle.cjs'),
  alias: { '@': path.join(FRONT, 'src') },
  loader: { '.css': 'empty', '.tsx': 'tsx', '.ts': 'ts' },
  jsx: 'automatic',
  external: ['react', 'react-dom', 'react-router-dom'],
  logLevel: 'info',
});

// 2) 服务端渲染为静态标记
const mod = require(path.join(FRONT, 'prerender-bundle.cjs'));
const ssrHtml = ReactDOMServer.renderToStaticMarkup(React.createElement(mod.App));
console.log('[prerender] ssrHtml length =', ssrHtml.length);

// 3) 注入 dist/index.html 的 #root
let html = fs.readFileSync(path.join(OUT, 'index.html'), 'utf8');
const rootOpen = '<div id="root"></div>';
if (html.includes(rootOpen)) {
  html = html.replace(rootOpen, '<div id="root">' + ssrHtml + '</div>');
} else {
  html = html.replace(/<div id="root">[\s\S]*?<\/div>\s*<\/body>/,
    '<div id="root">' + ssrHtml + '</div></body>');
}

// 4) SEO/GEO <head> 元数据：替换已有 title/description（避免重复），再注入 og/canonical/JSON-LD
const title = '七虎AI · 个人体验 AI、办公提效与 AI 创收的一站式平台';
const desc = '七虎AI 是面向个人与职场用户的 AI 平台：低价订阅无限 Token、垂直办公模板、可交易技能市场、AI 创作试炼场与低成本养模型，让每个人用 AI 把事做成。';
const jsonLd = {
  '@context': 'https://schema.org',
  '@type': 'SoftwareApplication',
  name: '七虎AI',
  applicationCategory: 'BusinessApplication',
  operatingSystem: 'Web',
  offers: { '@type': 'Offer', price: '0', priceCurrency: 'CNY' },
  aggregateRating: { '@type': 'AggregateRating', ratingValue: '4.8', reviewCount: '1000' },
  url: 'https://ai.qihuyun.com/',
};
// 替换/新增 title 与 description（避免与源模板重复）
html = html.replace(/<title>[\s\S]*?<\/title>/, `    <title>${title}</title>`);
if (/<meta name="description"/.test(html)) {
  html = html.replace(/<meta name="description"[^>]*>/, `    <meta name="description" content="${desc}" />`);
} else {
  html = html.replace('</head>', `    <meta name="description" content="${desc}" />\n  </head>`);
}
// 注入 og / canonical / JSON-LD（仅在尚不存在时，防止重复注入）
const extra = [
  `    <meta property="og:title" content="${title}" />`,
  `    <meta property="og:description" content="${desc}" />`,
  `    <meta property="og:type" content="website" />`,
  `    <meta name="twitter:card" content="summary_large_image" />`,
  `    <link rel="canonical" href="https://ai.qihuyun.com/" />`,
  `    <script type="application/ld+json">${JSON.stringify(jsonLd)}</script>`,
].join('\n');
if (!html.includes('rel="canonical"')) {
  html = html.replace('</head>', extra + '\n  </head>');
}

fs.writeFileSync(path.join(OUT, 'index.html'), html);

// 5) robots.txt
fs.writeFileSync(path.join(OUT, 'robots.txt'),
  'User-agent: *\nAllow: /\n\nSitemap: https://ai.qihuyun.com/sitemap.xml\n');

// 6) sitemap.xml（当前公开可索引页仅首页；其余为登录后页面，按需在后续迭代补充）
const urls = ['https://ai.qihuyun.com/'];
const sitemap = '<?xml version="1.0" encoding="UTF-8"?>\n' +
  '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">\n' +
  urls.map(u => `  <url><loc>${u}</loc><changefreq>daily</changefreq><priority>1.0</priority></url>`).join('\n') +
  '\n</urlset>\n';
fs.writeFileSync(path.join(OUT, 'sitemap.xml'), sitemap);

// 7) 清理临时文件
[path.join(FRONT, 'prerender-entry.tsx'), path.join(FRONT, 'prerender-bundle.cjs')].forEach(f => fs.existsSync(f) && fs.unlinkSync(f));

console.log('PRERENDER DONE');