import { NextResponse } from "next/server";
import type { NextRequest } from "next/server";
import { locales, fallbackLocale, resolveLocale } from "./src/config/i18n";
import type { Locale } from "./src/config/i18n";

const PUBLIC_FILE = /\.(.*)$/;

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

  // Пропускаем API, статические ресурсы и файлы
  if (pathname.startsWith("/api") || PUBLIC_FILE.test(pathname)) {
    return NextResponse.next();
  }

  const segments = pathname.split("/").filter(Boolean);
  const firstSegment = segments[0];

  // Если локаль уже присутствует — пропускаем
  if (locales.includes(firstSegment as Locale)) {
    return NextResponse.next();
  }

  // Детект по Accept-Language -> fallback
  const detected = resolveLocale(request.headers.get("accept-language"));
  const locale = detected || fallbackLocale;

  const redirectPath = ["", locale, ...segments].join("/");
  const url = new URL(redirectPath || `/${locale}`, request.url);
  return NextResponse.redirect(url);
}

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