import { parentPort } from 'node:worker_threads';
import {
  decodeBuffer,
  encodeBuffer,
} from './eu4_han_convert/src/codec.js';

const PROFILE = 'compatible';
const bom = Buffer.from([0xef, 0xbb, 0xbf]);

function decodeUtf8Source(buffer) {
  const offset = buffer.subarray(0, bom.length).equals(bom) ? bom.length : 0;
  return new TextDecoder('utf-8', { fatal: true }).decode(buffer.subarray(offset));
}

parentPort.on('message', ({ id, operation, input }) => {
  try {
    const buffer = Buffer.from(input);
    const output = operation === 'encode'
      ? encodeBuffer(decodeUtf8Source(buffer), { profile: PROFILE })
      : Buffer.from(decodeBuffer(buffer), 'utf8');
    parentPort.postMessage({ id, output });
  } catch (error) {
    parentPort.postMessage({ id, error: error.message });
  }
});