import fs from "node:fs";
import type { IncomingMessage, ServerResponse } from "node:http";
import path from "node:path";

const MIME_TYPES: Record<string, string> = {
	".html": "text/html; charset=utf-8",
	".js": "text/javascript; charset=utf-8",
	".mjs": "text/javascript; charset=utf-8",
	".css": "text/css; charset=utf-8",
	".json": "application/json; charset=utf-8",
	".svg": "image/svg+xml",
	".png": "image/png",
	".jpg": "image/jpeg",
	".jpeg": "image/jpeg",
	".gif": "image/gif",
	".webp": "image/webp",
	".avif": "image/avif",
	".ico": "image/x-icon",
	".txt": "text/plain; charset=utf-8",
	".woff": "font/woff",
	".woff2": "font/woff2",
	".ttf": "font/ttf",
	".map": "application/json; charset=utf-8",
	".wasm": "application/wasm",
	".webmanifest": "application/manifest+json",
};

export const createStaticHandler = (distDir: string) => {
	return (req: IncomingMessage, res: ServerResponse, url: URL) => {
		if (req.method !== "GET" && req.method !== "HEAD") {
			res.writeHead(404).end();
			return;
		}

		const pathname = decodeURIComponent(url.pathname);
		const filePath = path.join(distDir, pathname);
		if (!filePath.startsWith(distDir)) {
			res.writeHead(403).end();
			return;
		}

		if (!fs.existsSync(filePath) || !fs.statSync(filePath).isFile()) {
			res.writeHead(404).end();
			return;
		}

		const cacheControl = pathname.startsWith("/assets/")
			? "public, max-age=31536000, immutable"
			: "public, max-age=0, must-revalidate";
		res.writeHead(200, {
			"content-type":
				MIME_TYPES[path.extname(filePath).toLowerCase()] ??
				"application/octet-stream",
			"cache-control": cacheControl,
		});
		fs.createReadStream(filePath).pipe(res);
	};
};