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 },
  })
}