import fs from 'fs';
import path from 'path';

import { parseCsv } from './localization';

import type { LocaleMap } from './localization';

declare global {
  var __serverLocaleCache: LocaleMap | undefined;
}

/**
 * Loads and merges EN + DE locale CSVs from the public directory.
 * Cached for the lifetime of the server process.
 * Server-only — never import from client components.
 */
export function getServerLocaleMap(): LocaleMap {
  if (globalThis.__serverLocaleCache) return globalThis.__serverLocaleCache;

  const pub = path.join(process.cwd(), 'public');

  function load(filename: string): LocaleMap {
    try {
      return parseCsv(fs.readFileSync(path.join(pub, filename), 'utf8'));
    } catch {
      return new Map();
    }
  }

  const merged: LocaleMap = new Map([
    ...load('factorio_english_items.csv'),
    ...load('factorio_german_items.csv'),
  ]);
  globalThis.__serverLocaleCache = merged;
  return merged;
}