import { metadata } from '@/app/metadata'
import { getAllPostsMeta } from '@/lib/posts'

const SITE_URL = process.env.SITE_URL || 'http://localhost:3000'

function escapeXml(str: string) {
  return str
    .replace(/&/g, '&')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;')
    .replace(/'/g, '&apos;')
}

export async function GET(req: Request) {
  const posts = getAllPostsMeta()

  const updated =
    posts.length > 0 ? new Date(posts[0].date).toISOString() : new Date().toISOString()

  const entries = posts
    .map((p) => {
      const url = `${SITE_URL}/posts/${p.slug}`
      const date = new Date(p.date).toISOString()
      return `
  <entry>
    <title>${escapeXml(p.title)}</title>
    <link href="${url}" rel="alternate" type="text/html" />
    <id>${url}</id>
    <published>${date}</published>
    <updated>${date}</updated>
    <content type="html" src="${url}" />
    <summary>${escapeXml(p.description)}</summary>
  </entry>`
    })
    .join('')

  const feed = `<?xml version="1.0" encoding="UTF-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
  <id>${SITE_URL}/</id>
  <title>${escapeXml(metadata.title!.toString())}</title>
  <updated>${updated}</updated>
  <author>
    <name>${escapeXml(metadata.creator!.toString())}</name>
  </author>
  <link href="${SITE_URL}/feed" rel="self" type="application/atom+xml" />
  <link href="${SITE_URL}" rel="alternate" type="text/html" />
  <rights> © ${new Date().getFullYear()} Frank Borisjuk </rights>
  ${entries}
</feed>`

  const accept = req.headers.get('accept') || ''
  const contentType = accept.includes('application/atom+xml')
    ? 'application/atom+xml; charset=utf-8'
    : 'application/xml; charset=utf-8'

  return new Response(feed, {
    headers: { 'Content-Type': contentType },
  })
}