import {parseArgs} from 'node:util';

class ArgumentsMissingError extends Error {
  constructor(values) {
    let msg;
    if (!values.variable1 && !values.variable2) {
      msg = 'both variable1 and variable2 must be provided';
    } else {
      msg = `${!values.variable1 ? 'variable1' : 'variable2'} must be provided`;
    }
    super(msg);
    this.code = 'ERR_PARSE_ARGS_ARGUMENTS_MISSING';
  }
}

try {
  const {values} = parseArgs({
    options: {
      help: {
        type: 'boolean',
        short: 'h'
      },
      variable1: {
        short: 'x',
        type: 'string'
      },
      variable2: {
        short: 'y',
        type: 'string'
      }
    }
  });
  if (values.help) {
    console.info(`adds two numbers together: node cli.mjs -x 99 -y 22`);
  } else if (values.variable1 && values.variable2) {
    console.info(`${values.variable1} + ${values.variable2} = ${Number(values.variable1) + Number(values.variable2)}`);
  } else {
    throw new ArgumentsMissingError(values);
  }
} catch (err) {
  const parseErrors = [
    'ERR_PARSE_ARGS_INVALID_OPTION_VALUE',
    'ERR_PARSE_ARGS_UNKNOWN_OPTION',
    'ERR_PARSE_ARGS_ARGUMENTS_MISSING'
  ];
  if (parseErrors.includes(err.code)) {
    console.error(err.message);
    process.exitCode = 1;
  } else {
    throw err;
  }
}