// One-shot helper (not a runtime dependency): normalize a Natural Earth admin-0
// GeoJSON into public/countries.geo.json with `id` = ISO_A3 and properties.name.
// Usage: node scripts/normalize-geojson.mjs <input.geo.json>
import { readFileSync, writeFileSync } from 'node:fs';

const input = process.argv[2];
if (!input) {
  console.error('usage: node scripts/normalize-geojson.mjs <input.geo.json>');
  process.exit(1);
}

const geo = JSON.parse(readFileSync(input, 'utf8'));

// ISO_A3 can be missing/empty for a few territories; fall back to a small table
// keyed by the Natural Earth `NAME` value, then to the (ISO_A2) feature id.
const NAME_TO_A3 = {
  'South Sudan': 'SSD',
  'Somaliland': 'SOL',
  'N. Cyprus': 'CNX',
  'Antarctica': 'ATA',
  'Western Sahara': 'ESH',
  'Falkland Is.': 'FLK',
  'Falkland Islands': 'FLK',
  'Heard & Island McDonald Is.': 'HMD',
  'French Southern & Antarctic Lands': 'ATF',
  'Saint Helena, Ascension & Tristan da Cunha': 'SHN',
  'Bouvet Is.': 'BVT',
  'Pitcairn Is.': 'PCN',
  'S. Geo. de Las Malvinas (Falkland Is.)': 'FLK',
};

let withA3 = 0;
let fallback = 0;
const fallbackNames = [];
const out = {
  type: 'FeatureCollection',
  features: geo.features.map((f) => {
    const p = f.properties ?? {};
    let iso3 =
      (p.ADM0_A3 ?? p.ISO_A3 ?? p.ISO_A3_EH ?? p.SOV_A3 ?? '').toString().trim().toUpperCase();
    const name = (p.ADMIN ?? p.NAME ?? f.id ?? 'Unknown').toString().trim();
    if (!iso3) {
      iso3 = NAME_TO_A3[name] ?? (typeof f.id === 'string' && f.id.length === 2 ? f.id.toUpperCase() : 'ZZZ');
      fallback++;
      fallbackNames.push(name);
    } else {
      withA3++;
    }
    // Trim properties to the two fields the client actually uses (keeps the file small).
    const feature = {
      type: 'Feature',
      id: iso3,
      properties: { name },
      geometry: f.geometry,
    };
    return feature;
  }),
};

writeFileSync(new URL('../public/countries.geo.json', import.meta.url), JSON.stringify(out));
console.log(`features=${out.features.length} withA3=${withA3} fallback=${fallback}`);
if (fallbackNames.length) console.log('fallbacks:', [...new Set(fallbackNames)].join(', '));
const size = JSON.stringify(out).length;
console.log(`output bytes=${size}`);