route.ts

import { fetchSanity, groq } from '@/lib/sanity/fetch';
import processUrl, { BASE_URL } from '@/lib/processUrl';
import { Feed } from 'feed';
import { escapeHTML, toHTML } from '@portabletext/to-html';
import { urlFor } from '@/lib/sanity/urlFor';

export async function GET() {
    try {
        const { blog, posts, site } = await fetchSanity<{
            blog: Sanity.Page;
            posts: Array<Sanity.BlogPost & { image?: string }>;
            site: { copyright: string };
        }>(
            groq`{
                'blog': *[_type == 'page' && metadata.slug.current == 'blog'][0]{
                    _type,
                    title,
                    metadata,
                    'image': metadata.image.asset->url
                },
                'posts': *[_type == 'blog.post']{
                    _type,
                    body,
                    publishDate,
                    metadata
                },
                'site': *[_type == 'site'][0]{
                    'copyright': pt::text(copyright)
                }
            }`,
            { tags: ['blog-rss'] },
        );

        if (!blog || !posts || !site) {
            throw new Error("Failed to fetch necessary data");
        }

        const url = processUrl(blog);

        const feed = new Feed({
            title: blog?.title || blog.metadata.title,
            description: blog.metadata.description,
            link: url,
            id: url,
            copyright: site.copyright,
            favicon: `${BASE_URL}favicon.ico`,
            language: 'en',
            generator: 'https://github.com/nuotsu/sanitypress',
        });

        posts.forEach((post) => {
            if (post && post.metadata && post.body) {
                feed.addItem({
                    title: escapeHTML(post.metadata.title),
                    description: post.metadata.description,
                    id: processUrl(post),
                    link: processUrl(post),
                    date: new Date(post.publishDate),
                    content: toHTML(post.body, {
                        components: {
                            types: {
                                image: ({ value }) => {
                                    const img = `<img src="${urlFor(value).url()}" alt="${value.alt}" />`;
                                    const figcaption = value.caption
                                        ? `<figcaption>${value.caption}</figcaption>`
                                        : '';
                                    return `<figure>${img}${figcaption}</figure>`;
                                },
                                code: ({ value }) =>
                                    `<pre><code>${escapeHTML(value.code)}</code></pre>`,
                            },
                        },
                    }),
                    image: post.image,
                });
            }
        });

        return new Response(feed.atom1(), {
            headers: {
                'Content-Type': 'application/atom+xml',
            },
        });
    } catch (error) {
        console.error("Error generating RSS feed:", error);
        return new Response("Internal Server Error", { status: 500 });
    }
}