Website Migration SEO Validation

async function validateMigrationSEO(urls) {
  const headers = { 'Authorization': 'Bearer YOUR_API_KEY' };
  const issues = [];

  for (const url of urls) {
    const domain = new URL(url).hostname;

    const [canonical, meta, robots, redirect] = await Promise.all([
      // validateReciprocity audits hreflang return-links (Developer+ tier)
      fetch(`https://api.edgedns.dev/v1/domain/canonical?url=${url}&validateReciprocity=true`, { headers }),
      fetch(`https://api.edgedns.dev/v1/domain/meta?url=${url}`, { headers }),
      fetch(`https://api.edgedns.dev/v1/domain/robots?domain=${domain}`, { headers }),
      // canonicalCheck=true compares the final URL to its <link rel=canonical>
      fetch(`https://api.edgedns.dev/v1/domain/redirect?url=${url}&canonicalCheck=true`, { headers }),
    ].map(p => p.then(r => r.json())));

    if (canonical.data.canonical && canonical.data.canonical !== url) {
      issues.push({ url, issue: `Canonical mismatch: ${canonical.data.canonical}` });
    }

    // Hreflang reciprocity: every alternate must link back
    const missing = canonical.data.hreflangReciprocity?.missingReturnLinks ?? [];
    for (const m of missing) {
      issues.push({ url, issue: `Hreflang ${m.lang} (${m.href}) has no return link` });
    }

    if (!meta.data.title) issues.push({ url, issue: 'Missing title tag' });
    if (!meta.data.description) issues.push({ url, issue: 'Missing meta description' });

    // Redirect-chain checks: chain length, 302-for-permanent, canonical drift
    if (redirect.data.totalRedirects > 2) {
      issues.push({ url, issue: `Redirect chain has ${redirect.data.totalRedirects} hops — consolidate to ≤ 1` });
    }
    for (const issue of redirect.data.structuredIssues ?? []) {
      if (issue.code === 'redirect-temporary-for-permanent') {
        issues.push({ url, issue: '302/307 used for what looks like a permanent move — switch to 301 for ranking signals' });
      }
      if (issue.code === 'redirect-canonical-mismatch') {
        issues.push({ url, issue: `Redirect lands on ${redirect.data.finalUrl} but its canonical is ${redirect.data.canonicalMatch?.canonicalUrl}` });
      }
    }

    // Verify Googlebot, GPTBot, and ClaudeBot are not accidentally blocked
    const rules = robots.data.effectiveRulesByCrawler ?? {};
    for (const bot of ['Googlebot', 'GPTBot', 'ClaudeBot']) {
      if (rules[bot]?.effective === 'disallow-all') {
        issues.push({ url, issue: `${bot} is disallow-all in robots.txt` });
      }
    }
  }

  // validateUrls samples and HEAD-checks each listed sitemap URL (Pro+ tier)
  const domain = new URL(urls[0]).hostname;
  const sitemapCheck = await fetch(
    `https://api.edgedns.dev/v1/domain/sitemap?domain=${domain}&validateUrls=true`,
    { headers }
  ).then(r => r.json());

  if (!sitemapCheck.data.accessible) {
    issues.push({ url: 'sitemap.xml', issue: 'Sitemap not accessible' });
  }
  const brokenSample = sitemapCheck.data.sampleValidation?.broken ?? [];
  for (const b of brokenSample) {
    issues.push({ url: b.url, issue: `Sitemap URL returned ${b.status}` });
  }

  return { passed: issues.length === 0, issues };
}