proxy.ts

import { type NextRequest, NextResponse } from "next/server";

export function proxy(request: NextRequest) {
  const { pathname } = request.nextUrl;

  // If path ends in .md, serve the markdown route
  if (pathname.endsWith(".md")) {
    return NextResponse.rewrite(new URL("/md", request.url));
  }

  // Check Accept header — if text/markdown appears before text/html, serve markdown
  const accept = request.headers.get("accept") ?? "";
  const types = accept.split(",").map((t) => t.trim().split(";")[0].trim());
  const mdIndex = types.indexOf("text/markdown");
  const htmlIndex = types.indexOf("text/html");

  if (mdIndex !== -1 && (htmlIndex === -1 || mdIndex < htmlIndex)) {
    return NextResponse.rewrite(new URL("/md", request.url));
  }

  return NextResponse.next();
}

export const config = {
  matcher: ["/", "/.md"],
};