// Server entry point. Runs headless (`npm run server`) or inside an Electron utilityProcess.
import { DEFAULT_MAP_ID, NET_PORT } from '../shared/constants';
import { loadCharacterStats, loadMap, loadMaterials, resolveAssetsDir } from './assets';
import { Game } from './game';
import { GameServer } from './net';

interface ParentPort {
  postMessage(message: unknown): void;
}

/** Set by Electron when this file runs in a utilityProcess. */
const parentPort = (process as { parentPort?: ParentPort }).parentPort;

function arg(name: string): string | undefined {
  const prefix = `--${name}=`;
  return process.argv.find((a) => a.startsWith(prefix))?.slice(prefix.length);
}

function main(): void {
  const assetsDir = resolveAssetsDir();
  const mapId = arg('map') ?? DEFAULT_MAP_ID;
  const port = Number(arg('port') ?? NET_PORT);
  // The only place the seed is drawn; everything downstream uses the seeded RNG.
  const seed = Number(arg('seed') ?? Date.now() % 0x7fffffff);

  const materials = loadMaterials(assetsDir);
  const { definition, terrain } = loadMap(assetsDir, mapId, materials);
  const game = new Game({
    map: definition,
    terrain,
    materials,
    seed,
    loadCharacter: (id) => loadCharacterStats(assetsDir, id),
  });

  const server = new GameServer(game, port, '0.0.0.0', () => {
    console.log(`[server] map "${mapId}" (seed ${seed}) listening on :${port}`);
    parentPort?.postMessage({ type: 'ready', port });
  });
  server.start();

  const shutdown = (): void => {
    server.close();
    process.exit(0);
  };
  process.on('SIGINT', shutdown);
  process.on('SIGTERM', shutdown);
}

try {
  main();
} catch (err) {
  console.error('[server] failed to start:', err);
  parentPort?.postMessage({ type: 'error', message: err instanceof Error ? err.message : String(err) });
  process.exit(1);
}