import { NextResponse } from "next/server";
import type { NextRequest } from "next/server";
import { SUPPORTED_LOCALES, DEFAULT_LOCALE, LOCALE_COOKIE, getLocaleFromPath } from "@/lib/i18n/locales";

const OLD_SERBIAN_PATHS = ["products", "about", "contact", "checkout"];

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 = DEFAULT_LOCALE;

    if (cookieLocale && SUPPORTED_LOCALES.includes(cookieLocale as typeof SUPPORTED_LOCALES[number])) {
      locale = cookieLocale;
    } else if (acceptLanguage.includes("en")) {
      locale = "en";
    }

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

  const isOldSerbianPath = OLD_SERBIAN_PATHS.some(
    (path) => pathname === `/${path}` || pathname.startsWith(`/${path}/`)
  );

  if (isOldSerbianPath) {
    let locale = DEFAULT_LOCALE;

    if (cookieLocale && SUPPORTED_LOCALES.includes(cookieLocale as typeof SUPPORTED_LOCALES[number])) {
      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|.*\\..*).*)",
  ],
};