import type { APIRoute } from 'astro'
import { site } from '@shared/lib/site'

export const prerender = true

// build.format 'file' emits x/index.astro as x.html (the hosting serves no
// x/ directory), so nested index pages collapse to that file; the root index
// stays "/".
const pages = import.meta.glob('./**/*.astro')

const urls = Object.keys(pages)
  .map((file) => file.replace(/^\.\//, '').replace(/\.astro$/, '.html'))
  .sort((a, b) => {
    const depthA = a.split('/').length
    const depthB = b.split('/').length
    if (depthA !== depthB) return depthA - depthB
    return a < b ? 1 : -1
  })
  .map((path) => {
    if (path === 'index.html') return '/'
    if (path.endsWith('/index.html')) return `/${path.slice(0, -'/index.html'.length)}.html`
    return `/${path}`
  })

const escapeXml = (value: string) => value.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;').replace(/'/g, '&apos;')

export const GET: APIRoute = () => {
  const environment = process.env.NODE_ENV || 'production'
  const baseUrl = environment !== 'development' ? site.previewUrl : ''
  // No <lastmod>: it is optional, and stamping every url with the build time
  // said nothing about the pages while making the file differ on every build.
  const entries = urls
    .map(
      (url) => `<url>
	<loc>${escapeXml(`${baseUrl}${url}`)}</loc>
</url>`,
    )
    .join('\n')
  const body = `<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd" xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">

${entries}
</urlset>
`

  return new Response(body, {
    headers: {
      'Content-Type': 'application/xml; charset=utf-8',
    },
  })
}