import 'server-only';
import { isoLookupFromCountries, worldPaths } from '@/lib/map-geo';
import type { CountrySummary } from '@/lib/types';
import type { BaseFeature } from './indicator-map';

/** Server-side: world geometry joined with the country list (slug, flag) — values are added client-side. */
export function baseFeatures(countries: CountrySummary[]): { features: BaseFeature[]; sphere: string } {
  const { paths, sphere } = worldPaths();
  const byId = new Map(countries.map((c) => [c.id, c]));
  const numeric = isoLookupFromCountries(countries as Array<{ id: string; iso_numeric?: string | null }>);
  const features = paths.map((p) => {
    const iso3 = p.iso3 ?? (p.numeric ? numeric.get(p.numeric) ?? null : null);
    const c = iso3 ? byId.get(iso3) : undefined;
    return { iso3, name: c?.name ?? p.name, slug: c?.slug ?? null, flag: c?.flag ?? null, d: p.d };
  });
  return { features, sphere };
}