/**
 * `/blog/rss.xml?lang=xx`: the blog as RSS, in one language — a feed reader
 * subscribes to one, and a post only has the addresses of the languages it was
 * translated into.
 */
import {
  defineEventHandler,
  getQuery,
  getRequestHeaders,
  setResponseHeader,
  setResponseStatus,
} from 'h3';

import { pireonApi, resolveLocale } from '../../../app/core/api';
import { BLOG_CATEGORY, byPublication } from '../../../app/core/blog';
import { copyFor } from '../../../app/core/copy';
import { originFromHeaders } from '../../../app/core/origin';
import { listingPath } from '../../../app/core/routes';
import { buildFeed } from '../../../app/core/rss';

export default defineEventHandler(async (event) => {
  const locale = resolveLocale(getQuery(event)['lang']);
  const origin = originFromHeaders(getRequestHeaders(event)) ?? '';
  const copy = copyFor(locale);

  const { data, error } = await pireonApi.pages(locale, {
    category: BLOG_CATEGORY[locale],
    per_page: 50,
  });

  if (error) {
    setResponseStatus(event, 503);
    setResponseHeader(event, 'Cache-Control', 'no-store');

    return 'Feed temporarily unavailable';
  }

  setResponseHeader(
    event,
    'Content-Type',
    'application/rss+xml; charset=utf-8',
  );

  return buildFeed(
    origin,
    locale,
    {
      title: `Pireon — ${copy.blog.title}`,
      description: copy.blog.lead,
      link: listingPath('blog', locale),
    },
    byPublication(data ?? []),
  );
});