import { match } from "@formatjs/intl-localematcher";
import Negotiator from "negotiator";
import type { NextRequest } from "next/server";
import { NextResponse } from "next/server";

const locales = ["en", "pl"];
const defaultLocale = "pl";

function getLocale(request: NextRequest) {
  const headers = {
    "accept-language": request.headers.get("accept-language") || "",
  };
  const languages = new Negotiator({ headers }).languages();
  return match(languages, locales, defaultLocale);
}

export function middleware(request: NextRequest) {
  const pathname = request.nextUrl.pathname;
  const pathnameIsMissingLocale = locales.every(
    (locale) => !pathname.startsWith(`/${locale}/`) && pathname !== `/${locale}`
  );

  if (pathnameIsMissingLocale) {
    const locale = getLocale(request);
    return NextResponse.redirect(new URL(`/${locale}${pathname}`, request.url));
  }
}

export const config = {
  matcher: ["/((?!api|_next/static|_next/image|favicon.ico).*)"],
};