import { evaluate, simplify } from 'mathjs';

function done(data: string): void {
  if (process && process.send) {
    process.send(data);
  }
}

process.once('message', (msg) => {
  msg = msg.toString();

  const dat = msg.split(' ');
  if (!(dat.length > 1)) {
    return;
  }

  let expr = dat.slice(1).join(' ');

  if (!expr) {
    return done('null');
  }
  if (expr.indexOf('=') === expr.length - 1) {
    expr = expr.substring(0, expr.length - 1);
  }

  expr = expr.replace(/π/g, 'pi');
  let result = 'null';

  try {
    if (dat[0] === 'eval') {
        result = evaluate(expr);
    } else if (dat[0] === 'simplify') {
        result = simplify(expr).toString();
    }
  } catch (e) {
    return done(e.message);
  }

  return done(result.toString());
});