const fs = require('fs');
const path = require('path');

const SITE_URL = 'https://yuzhiran.com';
const OUT_DIR = path.join(__dirname, '..', 'out');

const PRIORITIES = {
  '/': 1.0,
  '/tools': 0.9,
  '/courses': 0.9,
  '/skills': 0.8,
  '/marketplace': 0.8,
  '/practices': 0.8,
  '/contents': 0.8,
  '/prompts': 0.8,
  '/prompts/workshop': 0.7,
  '/models': 0.7,
  '/sandbox': 0.7,
  '/sandbox/compare': 0.6,
  '/sandbox/code': 0.6,
  '/sandbox/share': 0.6,
  '/discover': 0.7,
  '/discover/hot': 0.6,
  '/discover/tools': 0.6,
  '/discover/daily': 0.6,
  '/community': 0.6,
  '/circles': 0.6,
  '/resources': 0.7,
  '/about': 0.5,
  '/privacy': 0.3,
  '/terms': 0.3,
  '/ai-agreement': 0.3,
  '/search': 0.5,
};

function walkDir(dir, basePath = '') {
  const entries = fs.readdirSync(dir, { withFileTypes: true });
  const urls = [];
  for (const entry of entries) {
    const fullPath = path.join(dir, entry.name);
    const relativeName = path.join(basePath, entry.name);
    if (entry.isDirectory()) {
      if (entry.name.startsWith('_') || entry.name.startsWith('.')) continue;
      urls.push(...walkDir(fullPath, relativeName));
    } else if (entry.name === 'page.html' || entry.name.endsWith('.html')) {
      if (relativeName === 'index.html' || relativeName === 'page.html') {
        urls.push({ path: '/', file: fullPath });
      } else {
        let urlPath = '/' + relativeName.replace(/\.html$/, '').replace(/\/index$/, '').replace(/\/page$/, '');
        urls.push({ path: urlPath, file: fullPath });
      }
    }
  }
  return urls;
}

function generateSitemap(urls) {
  const now = new Date().toISOString().split('T')[0];
  let xml = '<?xml version="1.0" encoding="UTF-8"?>\n';
  xml += '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">\n';
  const seen = new Set();
  for (const url of urls) {
    if (seen.has(url.path)) continue;
    seen.add(url.path);
    if (url.path.startsWith('/admin') || url.path.startsWith('/_next') || url.path.startsWith('/api') || url.path === '/404') continue;
    if (url.path.includes('/[') || url.path.includes(']')) continue;
    const depth = url.path.split('/').filter(Boolean).length;
    const changefreq = depth <= 1 ? 'weekly' : 'monthly';
    const priority = PRIORITIES[url.path];
    const computedPriority = priority !== undefined ? priority : Math.max(0.1, 0.7 - depth * 0.1);
    xml += '  <url>\n';
    xml += `    <loc>${SITE_URL}${url.path}</loc>\n`;
    xml += `    <lastmod>${now}</lastmod>\n`;
    xml += `    <changefreq>${changefreq}</changefreq>\n`;
    xml += `    <priority>${computedPriority.toFixed(1)}</priority>\n`;
    xml += '  </url>\n';
  }
  xml += '</urlset>';
  return xml;
}

if (!fs.existsSync(OUT_DIR)) {
  console.error('out/ directory not found. Run next build first.');
  process.exit(1);
}

const urls = walkDir(OUT_DIR);
console.log(`Found ${urls.length} HTML pages in output.`);
const sitemap = generateSitemap(urls);
const outputPath = path.join(OUT_DIR, 'sitemap.xml');
fs.writeFileSync(outputPath, sitemap, 'utf-8');
console.log(`Generated sitemap.xml with ${sitemap.split('<url>').length - 1} URLs → ${outputPath}`);

// Copy robots.txt from public/ to out/
const robotsSrc = path.join(__dirname, '..', 'public', 'robots.txt');
const robotsDst = path.join(OUT_DIR, 'robots.txt');
if (fs.existsSync(robotsSrc)) {
  fs.copyFileSync(robotsSrc, robotsDst);
  console.log(`Copied robots.txt → ${robotsDst}`);
}