import { fetchPostsSorted, resolveBlogPath } from "$src/lib/util/Blogs";

export const prerender = true;

const feedUpdated = new Date();

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

function makeThumbnail(post: App.BlogPost): string {
    if (!post.thumbnail) return '';

    const alt = !!post.thumbnailAlt ? ` alt="${escapeXml(post.thumbnailAlt)}"` : '';

    return `<br><br><img src="https://teasanctuary.ru${resolveBlogPath(post.slug, post.thumbnail)}"${alt}>`;
}

function makeAuthors(post: App.BlogPost): string {
    const authors =
        (post.authors == null
            ? []
            : typeof post.authors === 'string'
                ? [post.authors]
                : post.authors)
            .map(a => escapeXml(a));

    if (authors.length === 0) return '';

    let authorsString = authors[0];
    if (authors.length > 1) {
        const lastAuthor = authors.pop();
        authorsString = `${authors.join(', ')} и ${lastAuthor}`;
    }

    return `\n<author>${authorsString}</author>`;
}

export async function GET({ setHeaders }) {
    setHeaders({
        'Cache-Control': 'max-age=0, s-maxage=3600',
        'Content-Type': 'application/rss+xml',
    });
    const posts = await fetchPostsSorted();
    return new Response(String(`<?xml version="1.0" encoding="UTF-8" ?>
<rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:atom="http://www.w3.org/2005/Atom">
<channel>
<title>Блог Tea Sanctuary</title>
<description>Лента с новостями, заметками и событиями Tea Sanctuary</description>
<link>https://teasanctuary.ru/blog</link>
<atom:link href="https://teasanctuary.ru/blog/rss.xml" rel="self" type="application/rss+xml" />
<ttl>1800</ttl>
${posts.map((post) => `<item>
<title>${escapeXml(post.title)}</title>
<description><![CDATA[${escapeXml(post.description)}${makeThumbnail(post)}]]></description>${makeAuthors(post)}
<guid isPermaLink="true">https://teasanctuary.ru/blog/${post.slug}</guid>
<link>https://teasanctuary.ru/blog/${post.slug}</link>
<pubDate>${(new Date(post.date!)).toUTCString()}</pubDate>
</item>`).join("\n")}
</channel>
</rss>`))
}