import { NextResponse } from 'next/server';

export const dynamic = 'force-dynamic';

export async function GET() {
  const baseUrl = process.env.NEXT_PUBLIC_SITE_URL || 'https://canina.ir';
  const apiUrl = process.env.INTERNAL_API_URL || process.env.NEXT_PUBLIC_API_URL || 'http://localhost:4001/api';
  const apiBase = apiUrl.endsWith('/api') ? apiUrl : `${apiUrl.replace(/\/$/, '')}/api`;

  let blogs: any[] = [];
  try {
    const res = await fetch(`${apiBase}/blogs?page=1&limit=50`, { next: { revalidate: 3600 } });
    if (res.ok) {
      const data = await res.json();
      blogs = (data.data || []).filter((b: any) => !b.noIndex && b.status === 'PUBLISHED');
    }
  } catch (e) {
    console.error('Error fetching blogs for RSS feed:', e);
  }

  const itemsXml = blogs
    .map((b) => {
      const title = escapeXml(b.title || '');
      const link = `${baseUrl}/blog/${b.slug}`;
      const description = escapeXml(b.excerpt || b.metaDescription || '');
      const pubDate = b.publishedAt ? new Date(b.publishedAt).toUTCString() : b.createdAt ? new Date(b.createdAt).toUTCString() : new Date().toUTCString();
      const author = escapeXml(b.author ? `${b.author.firstName || ''} ${b.author.lastName || ''}`.trim() : 'کنینا فارما');
      const category = escapeXml(b.category?.name || 'دانشنامه سلامت حیوانات');

      return `
    <item>
      <title>${title}</title>
      <link>${link}</link>
      <guid isPermaLink="true">${link}</guid>
      <description><![CDATA[${description}]]></description>
      <pubDate>${pubDate}</pubDate>
      <author>${author}</author>
      <category>${category}</category>
      ${b.imageUrl ? `<enclosure url="${b.imageUrl.startsWith('http') ? b.imageUrl : `${baseUrl}${b.imageUrl}`}" type="image/jpeg" />` : ''}
    </item>`;
    })
    .join('');

  const rssFeed = `<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
  <channel>
    <title>مجله سلامت و دانشنامه تخصصی کنینا (Canina Pharma)</title>
    <link>${baseUrl}/blog</link>
    <description>جدیدترین مقالات علمی در زمینه مکمل‌های تخصصی، تغذیه و سلامت سگ و گربه از داروسازی کنینا آلمان</description>
    <language>fa-ir</language>
    <lastBuildDate>${new Date().toUTCString()}</lastBuildDate>
    <atom:link href="${baseUrl}/blog/rss.xml" rel="self" type="application/rss+xml"/>
    ${itemsXml}
  </channel>
</rss>`;

  return new NextResponse(rssFeed, {
    headers: {
      'Content-Type': 'application/xml; charset=utf-8',
      'Cache-Control': 'public, s-maxage=3600, stale-while-revalidate=86400',
    },
  });
}

function escapeXml(unsafe: string): string {
  return unsafe.replace(/[<>&'"]/g, (c) => {
    switch (c) {
      case '<':
        return '&lt;';
      case '>':
        return '&gt;';
      case '&':
        return '&amp;';
      case '\'':
        return '&apos;';
      case '"':
        return '&quot;';
      default:
        return c;
    }
  });
}