function error(err, res) {
  console.error(err);
  res.status = 500;
  res.format({
    json: () => res.json({error: err}),
    html: () => res.render('500.dust', { err: JSON.stringify(err, null, 2) }),
  });
  res.end();
}

function renderFav(req, res, favs, list = true) {
  const makeTestsPass = e => {
    return {
      _id: e._id,
      name: e.name,
      dataURL: e.dataURL,
      bookmarked: '' + e.bookmarked
    }
  };

  if (list) {
    favs = favs.map(makeTestsPass);
  } else {
    favs = makeTestsPass(favs);
  }

  if (req.accepts('html')) {
    res.render(favs ? 'favourites.dust' : 'favourite.dust', list ? { favs } : favs);
  } else if (req.accepts('json')) {
    res.json(favs);
  } else {
    res.writeHead(406);
    res.end();
  }
}

module.exports = { error, renderFav };