import fs from 'node:fs/promises';

import { defineCachedFunction } from 'nitropack/runtime';
import SQL from 'sql-template-strings';

import type { Config } from '~/locale/config.ts';
import type { Database } from '~/server/db.ts';
import type { UserRow } from '~/server/express/user.ts';
import { rootDir } from '~/server/paths.ts';
import { extractMetadata } from '~/src/blog/metadata.ts';
import type { PostWithContent } from '~/src/blog/metadata.ts';

export const getPosts = defineCachedFunction(async (config: Config): Promise<PostWithContent[]> => {
    const dir = `${rootDir}/locale/${config.locale}/blog`;
    const posts: PostWithContent[] = [];

    for (const file of await fs.readdir(dir)) {
        if (!file.endsWith('.md')) {
            continue;
        }
        const content = await fs.readFile(`${dir}/${file}`, 'utf-8');

        const slug = file.substring(0, file.length - 3);
        const metadata = extractMetadata(config, content);
        if (metadata !== undefined) {
            posts.push({ slug, content, ...metadata });
        }
    }

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

    return posts;
}, {
    name: 'blog',
    getKey: (config) => config.locale,
    maxAge: Infinity,
});

export interface BlogReactions {
    total: Record<string, number>;
    user?: string[];
}

export const getPostReactions = async (
    db: Database,
    locale: string,
    slug: string,
    userId: UserRow['id'] | undefined,
): Promise<BlogReactions> => {
    const totalReactions = await db.all<{ c: number; emoji: string }>(SQL`SELECT COUNT(*) as c, emoji
        FROM blog_reactions
        WHERE locale = ${locale} AND slug = ${slug}
        GROUP BY emoji`);

    const reactions: BlogReactions = {
        total: Object.fromEntries(totalReactions.map((row) => [row.emoji, row.c])),
    };

    if (userId !== undefined) {
        const userReactions = await db.all<{ emoji: string }>(SQL`SELECT emoji FROM blog_reactions
            WHERE locale = ${locale} AND slug = ${slug} AND user_id = ${userId}`);
        reactions.user = userReactions.map((row) => row.emoji);
    }

    return reactions;
};