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

const LOCALE_COOKIE = "NEXT_LOCALE";

export default function middleware(request: NextRequest) {
  const pathname = request.nextUrl.pathname;
  const cookieLocale = request.cookies.get(LOCALE_COOKIE)?.value;
  const acceptLanguage = request.headers.get("accept-language") || "";

  if (pathname === "/" || pathname === "") {
    let locale = "sr";

    if (cookieLocale && ["sr", "en", "de", "fr"].includes(cookieLocale)) {
      locale = cookieLocale;
    } else if (acceptLanguage.includes("en")) {
      locale = "en";
    }

    const url = request.nextUrl.clone();
    url.pathname = `/${locale}`;
    return NextResponse.redirect(url, 301);
  }

  const oldSerbianPaths = ["products", "about", "contact", "checkout"];
  const isOldSerbianPath = oldSerbianPaths.some(
    (path) => pathname === `/${path}` || pathname.startsWith(`/${path}/`)
  );

  if (isOldSerbianPath) {
    let locale = "sr";

    if (cookieLocale && ["sr", "en", "de", "fr"].includes(cookieLocale)) {
      locale = cookieLocale;
    } else if (acceptLanguage.includes("en")) {
      locale = "en";
    }

    const url = request.nextUrl.clone();
    url.pathname = `/${locale}${pathname}`;
    return NextResponse.redirect(url, 301);
  }

  return NextResponse.next();
}

export const config = {
  matcher: [
    "/",
    "/(sr|en|de|fr)/:path*",
    "/((?!api|_next|_vercel|.*\\..*).*)",
  ],
};