import type { Plugin } from "vite";
import { resolve, join } from "node:path";
import { readdirSync, readFileSync, writeFileSync } from "node:fs";
import matter from "gray-matter";

const BLOG_DIR = resolve("src/routes/blog");
const OUTPUT_FILE = resolve("src/data/posts.json");

function generatePostsJson() {
	const posts = readdirSync(BLOG_DIR)
		.filter((file) => file.endsWith(".mdx"))
		.map((file) => {
			const content = readFileSync(join(BLOG_DIR, file), "utf-8");
			const { data } = matter(content);
			return { ...data, slug: file.replace(".mdx", "") };
		})
		.sort(
			(a, b) =>
				new Date(b.date as string).getTime() -
				new Date(a.date as string).getTime(),
		);

	writeFileSync(OUTPUT_FILE, JSON.stringify(posts, null, 2));
}

export const blogPostsPlugin = (): Plugin => ({
	name: "blog-posts-gen",
	buildStart: generatePostsJson,
	configureServer(server) {
		server.watcher.on("change", (path) => {
			if (path.includes("src/routes/blog") && path.endsWith(".mdx")) {
				generatePostsJson();
			}
		});
	},
});