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

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

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

export default auth((req) => {
  const { nextUrl } = req;
  const isLoggedIn = !!req.auth;
  const pathname = nextUrl.pathname;

  // Check if there is any supported locale in the pathname
  const pathnameIsMissingLocale = locales.every(
    (locale) => !pathname.startsWith(`/${locale}/`) && pathname !== `/${locale}`
  );

  const host = req.headers.get("x-forwarded-host") || req.headers.get("host") || "localhost:3000";
  const proto = req.headers.get("x-forwarded-proto") || "http";
  const baseUrl = `${proto}://${host}`;

  // Redirect if there is no locale
  if (pathnameIsMissingLocale) {
    const locale = getLocale(req as any);
    return NextResponse.redirect(
      new URL(`/${locale}${pathname === '/' ? '' : pathname}`, baseUrl)
    );
  }

  const currentLocale = pathname.split('/')[1] || defaultLocale;
  const isLoginPage = pathname === `/${currentLocale}/login`;

  if (!isLoggedIn && !isLoginPage) {
    return NextResponse.redirect(new URL(`/${currentLocale}/login`, baseUrl));
  }

  if (isLoggedIn && isLoginPage) {
    return NextResponse.redirect(new URL(`/${currentLocale}/dashboard`, baseUrl));
  }

  return NextResponse.next();
});

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