import type { NextRequest } from 'next/server';

export const runtime = 'nodejs';
export const dynamic = 'force-dynamic';

type RouteContext = {
  params: Promise<{ path: string[] }>;
};

const BACKEND_INTERNAL_URL = process.env.BACKEND_INTERNAL_URL || 'http://127.0.0.1:8000';
const HOP_BY_HOP_HEADERS = new Set([
  'connection',
  'content-encoding',
  'content-length',
  'host',
  'keep-alive',
  'proxy-authenticate',
  'proxy-authorization',
  'te',
  'trailer',
  'transfer-encoding',
  'upgrade',
]);

async function proxyRequest(request: NextRequest, context: RouteContext): Promise<Response> {
  const { path } = await context.params;
  const upstream = new URL(`/${path.join('/')}`, BACKEND_INTERNAL_URL);
  upstream.search = request.nextUrl.search;

  const headers = new Headers(request.headers);
  for (const header of HOP_BY_HOP_HEADERS) {
    headers.delete(header);
  }

  const response = await fetch(upstream, {
    method: request.method,
    headers,
    body: request.method === 'GET' || request.method === 'HEAD' ? undefined : request.body,
    cache: 'no-store',
    duplex: 'half',
  } as RequestInit & { duplex: 'half' });

  const responseHeaders = new Headers(response.headers);
  for (const header of HOP_BY_HOP_HEADERS) {
    responseHeaders.delete(header);
  }

  return new Response(response.body, {
    status: response.status,
    statusText: response.statusText,
    headers: responseHeaders,
  });
}

export const GET = proxyRequest;
export const POST = proxyRequest;
export const PUT = proxyRequest;
export const PATCH = proxyRequest;
export const DELETE = proxyRequest;
export const HEAD = proxyRequest;
export const OPTIONS = proxyRequest;