import { readFile } from "node:fs/promises";
import path from "node:path";
import { PUBLIC_DIR, REPO_DIR, safeJoin } from "./paths";

/* Read-only file serving from the portfolio checkout, so the preview iframe
 * can load the site's real stylesheets and the post's images. */

const TYPES: Record<string, string> = {
  ".css": "text/css; charset=utf-8",
  ".png": "image/png",
  ".jpg": "image/jpeg",
  ".jpeg": "image/jpeg",
  ".gif": "image/gif",
  ".webp": "image/webp",
  ".svg": "image/svg+xml",
  ".ico": "image/x-icon",
  ".mp4": "video/mp4",
};

/** Stylesheets the preview may load, keyed by their /site/... path. */
const SITE_CSS = new Set(["app/globals.css", "styles/markdown-container.css", "styles/blog.css"]);

async function send(file: string): Promise<Response> {
  const type = TYPES[path.extname(file).toLowerCase()];
  if (!type) return new Response("not found", { status: 404 });
  try {
    const body = await readFile(file);
    return new Response(new Uint8Array(body), {
      headers: { "content-type": type, "cache-control": "no-cache" },
    });
  } catch {
    return new Response("not found", { status: 404 });
  }
}

/** /site/<css allowlist> -> repo file; /site/<anything else> -> repo public/. */
export function serveSitePath(segments: string[]): Promise<Response> {
  const rel = segments.join("/");
  if (SITE_CSS.has(rel)) return send(path.join(REPO_DIR, rel));
  return send(safeJoin(PUBLIC_DIR, ...segments));
}

export function servePublic(segments: string[]): Promise<Response> {
  return send(safeJoin(PUBLIC_DIR, ...segments));
}