var PAGE_PATHS = ['/v1/transit', '/v1/trains', '/v1/villo', '/v1/stops/board'];

function pageOrTransit(page) {
  return PAGE_PATHS[page] ? page : 0;
}

function buildUrl(base, pos, page, favIds) {
  if (page === 3) {
    return base + '/v1/stops/board?ids=' + favIds.join(',');
  }
  return base + PAGE_PATHS[pageOrTransit(page)] + '?' + (pos ? 'lat=' + pos.lat + '&lon=' + pos.lon : '');
}

function buildLineUrl(base, line, stopId, dest) {
  var url = base + '/v1/line?line=' + encodeURIComponent(line) + '&to=' + encodeURIComponent(stopId);
  if (dest) {
    url += '&dest=' + encodeURIComponent(dest);
  }
  return url;
}

module.exports = { buildUrl: buildUrl, buildLineUrl: buildLineUrl, pageOrTransit: pageOrTransit };