'use strict';

let d = require('debug')('gen2async');
let promisedNaturalAdd = require('./helpers').promisedNaturalAdd;

function asyncify(generator) {
  function iterate(g, resolvedValue) {
    let i = g.next(resolvedValue);

    if (i.done) {
      return i.value;
    }

    return i.value.then(res => {
      return iterate(g, res);
    }, err => {
      g.throw(err);
      return iterate(g);
    });

  }
  return function (args) {
    let g = generator.apply(generator, args);
    return iterate(g);
  }
}

function* gen() {
  d('START: gen');
  let res;
  try {
    res = yield promisedNaturalAdd(10, 5);
    d('First result value (10, 5): %s', res);
    res = yield promisedNaturalAdd(10, -5);
    d('Second result value (10, -5): %s', res);
  } catch (e) {
    d('Error gathered in catch: %s', e);
  }

  d('END: gen');
}

let afn = asyncify(gen);


afn().then(
  function () {
    d('END');
}).catch(
  function (e) {
    d('END with error: %s', e);
});

process.on('unhandledRejection', (err, promise) => {
  console.error('unhandledRejection: %s', err);
});