import { Router } from 'express';
import { handleErrorAsync } from '../../src/helpers.ts';
import fs from 'fs';
import { caches } from '../../src/cache.ts';

interface Post {
    slug: string;
    title: string;
    date: string;
    authors: string[];
    hero: string | null;
}

const router = Router();

router.get('/blog', handleErrorAsync(async (req, res) => {
    const posts = await caches.blog.fetch(async () => {
        const dir = `${__dirname}/../../data/blog`;
        const posts: Post[] = [];
        fs.readdirSync(dir).forEach((file) => {
            if (!file.endsWith('.md')) {
                return;
            }

            const slug = file.substring(0, file.length - 3);
            const content = fs.readFileSync(`${dir}/${file}`)
                .toString('utf-8')
                .split('\n')
                .filter((l) => !!l);

            let title = '',
                date = '',
                authorsRaw = '',
                authors = [],
                hero = null;

            try {
                title = content[0].match(/^# (.*)$/)![1];
            } catch {
                return;
            }

            try {
                [, date, authorsRaw] = content[1].match(/^<small>(\d\d\d\d-\d\d-\d\d) \| ([^|]*).*<\/small>$/)!;
                authors = authorsRaw.split(',').map((a) => {
                    a = a.trim();
                    const m = a.match(/^\[([^\]]+)]/);
                    if (m) {
                        return m[1];
                    }
                    return a;
                });
            } catch {
                return;
            }

            try {
                const classHeroImages = content.map((x) => x.match(/<img src="([^"]+)" class="hero/)).filter((x) => !!x);
                if (classHeroImages.length) {
                    hero = classHeroImages[0][1];
                    throw 'continue';
                }

                const images = content.map((x) => x.match(/^!\[[^\]]*]\(([^)]+)\)$/)).filter((x) => !!x);
                if (images.length) {
                    hero = images[0][1];
                }
            } catch {
            }

            posts.push({ slug, title, date, authors, hero });
        });

        posts.sort((a, b) => {
            if (a.date < b.date) {
                return 1;
            }
            if (a.date > b.date) {
                return -1;
            }
            return 0;
        });

        return posts;
    });

    return res.json(posts.filter((post) => {
        if (req.query.shortcuts !== undefined) {
            if (!global.config.blog || !global.config.blog.shortcuts) {
                return false;
            }

            if (!Object.values(global.config.blog.shortcuts).includes(post.slug)) {
                return false;
            }
        }

        if (req.query.slugs !== undefined) {
            const slugs = Array.isArray(req.query.slugs) ? req.query.slugs : [req.query.slugs];
            if (!slugs.includes(post.slug)) {
                return false;
            }
        }

        return true;
    }));
}));

export default router;