import { getSessionAccessToken, verifySession } from '@/lib/auth/dal';
import { backendFetchStream } from '@/lib/http/backend-fetch';

const ADMIN_MEMBER_EXCEL_PATH = '/api/v1/mngr/admin/excel/download';

const EXCEL_ROW_LIMIT = 100_000;

const EXCEL_TIMEOUT_MS = 60_000;

const DOWNLOAD_FAILED_MESSAGE =
  '엑셀 파일을 내려받지 못했습니다. 잠시 후 다시 시도해 주세요.';

const XLSX_CONTENT_TYPE =
  'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet';

export async function GET() {
  await verifySession();

  const accessToken = await getSessionAccessToken();

  const result = await backendFetchStream(ADMIN_MEMBER_EXCEL_PATH, {
    query: { pageIndex: 1, recordCountPerPage: EXCEL_ROW_LIMIT },
    accessToken: accessToken ?? undefined,
    timeoutMs: EXCEL_TIMEOUT_MS,
  });

  if (!result.ok) {
    return new Response(DOWNLOAD_FAILED_MESSAGE, {
      status: 502,
      headers: { 'Content-Type': 'text/plain; charset=utf-8' },
    });
  }

  const upstream = result.data;

  return new Response(upstream.body, {
    status: 200,
    headers: {
      'Content-Type': upstream.headers.get('content-type') ?? XLSX_CONTENT_TYPE,
      'Content-Disposition':
        upstream.headers.get('content-disposition') ??
        'attachment; filename="admins.xlsx"',
    },
  });
}