import { i18n } from "./i18n.config";

import { match as matchLocale } from "@formatjs/intl-localematcher";
import Negotiator from "negotiator";

import { NextResponse } from "next/server";

function getLocale(request: NextRequest): string | undefined {
  // Negotiator expects plain object so we need to transform headers
  const negotiatorHeaders: Record<string, string> = {};
  request.headers.forEach((value, key) => (negotiatorHeaders[key] = value));

  // @ts-ignore locales are readonly
  const locales: string[] = i18n.locales;

  // Use negotiator and intl-localematcher to get best locale
  let languages = new Negotiator({ headers: negotiatorHeaders }).languages(
    locales
  );

  const locale = matchLocale(languages, locales, i18n.defaultLocale);

  return locale;
}
export async function middleware(request: NextRequest) {
  const pathname = request.nextUrl.pathname;

  // List of routes that should bypass locale redirection
  const nonLocalizedPaths = [
    "/handler/signin",
    "/handler/sign-in",
    "/handler/signup",
    "/handler/sign-up",
    "/handler/oauth-callback",
    "/handler/account-settings",
  ];

  // Check if the pathname matches any non-localized paths
  if (nonLocalizedPaths.includes(pathname)) {
    return NextResponse.next();
  }

  // Iterate over all locales, check and strip the locale prefix
  const localeMatch = i18n.locales.find((locale) =>
    pathname.startsWith(`/${locale}/`)
  );

  if (localeMatch) {
    const strippedPath = pathname.replace(`/${localeMatch}`, "");

    // Handle specific paths after stripping the locale
    if (
      strippedPath === "/handler/sign-in" ||
      strippedPath === "/handler/sign-up" ||
      strippedPath === "/handler/oauth-callback"
    ) {
      request.nextUrl.pathname = strippedPath.replace("/sign-in", "/signin"); // Normalize path
      return NextResponse.next();
    }
  }

  // Ignore specific files (manifest, favicon, PNGs)
  if (
    ["/manifest.json", "/favicon.ico"].includes(pathname) ||
    /\/.*\.png$/.test(pathname)
  ) {
    return;
  }

  // If pathname is missing a locale, redirect
  const pathnameIsMissingLocale = i18n.locales.every(
    (locale) => !pathname.startsWith(`/${locale}/`) && pathname !== `/${locale}`
  );

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

  return NextResponse.next();
}

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