import path from "node:path";
import { writeFileSync } from "node:fs";
import { Feed } from "feed";
import { createContentLoader, type ContentData, type SiteConfig } from "vitepress";
import consola from "consola";
import { meta } from "../constants";

export async function generateFeed(config: SiteConfig): Promise<void> {
  const feed: Feed = new Feed({
    id: meta.hostname,
    link: meta.hostname,
    title: `FMHY blog`,
    description: meta.description,
    language: "en-US",
    image: "https://github.com/fmhy.png",
    favicon: `${meta.hostname}/favicon.ico`,
    copyright: `Copyright (c) 2023-present FMHY`,
  });

  const posts: ContentData[] = await createContentLoader("posts/*.md", {
    excerpt: true,
    render: true,
    transform: (rawData) => {
      return rawData.sort((a, b) => {
        return Number(new Date(b.frontmatter.date)) - Number(new Date(a.frontmatter.date));
      });
    },
  }).load();

  for (const { url, frontmatter, html } of posts) {
    feed.addItem({
      title: frontmatter.title as string,
      id: `${meta.hostname}${url.replace(/\/\d+\./, "/")}`,
      link: `${meta.hostname}${url.replace(/\/\d+\./, "/")}`,
      date: frontmatter.date,
      content: html!,
    });
  }

  writeFileSync(path.join(config.outDir, "feed.rss"), feed.rss2());
  return consola.info("Generated rss feed.");
}