import fs from "fs/promises";
import path from "path";
import matter from "gray-matter";
import { serialize } from "next-mdx-remote/serialize";
import { MDXRemoteSerializeResult } from "next-mdx-remote";

const EVENTS_PATH = path.join("content", "events");

export async function getYears(): Promise<string[]> {
  return await fs.readdir(EVENTS_PATH);
}

export async function getTermsByYear(year: string): Promise<string[]> {
  return await fs.readdir(path.join(EVENTS_PATH, year));
}

interface Metadata {
  name: string;
  short: string;
  date: string;
  online: boolean;
  location: string;
}

export interface Event {
  content: string | MDXRemoteSerializeResult<Record<string, unknown>>;
  metadata: Metadata;
}

export async function getEventBySlug(
  year: string,
  term: string,
  slug: string,
  convert = true
): Promise<Event> {
  const raw = await fs.readFile(
    path.join(EVENTS_PATH, year, term, `${slug}.event.md`),
    "utf-8"
  );
  const { content, data: metadata } = matter(raw);

  return {
    content: convert ? await serialize(content) : content,
    metadata: metadata as Metadata,
  };
}

export async function getEventsByTerm(
  year: string,
  term: string
): Promise<Event[]> {
  const files = (await fs.readdir(path.join(EVENTS_PATH, year, term)))
    .filter((name) => name.endsWith(".event.md"))
    .map((name) => name.slice(0, -".event.md".length));

  const props = await Promise.all(
    files.map((file) => getEventBySlug(year, term, file))
  );
  return props;
}