const defaultOrderRegistry = {};

function wbApplyPromiseOrdering(prom, orderRegistry) {
  let orderId;

  if (!orderRegistry)
    orderRegistry = defaultOrderRegistry;

  if (Object.keys(orderRegistry).length === 0) {
    orderRegistry.started = 0;
    orderRegistry.pendingCompletion = {};
    orderRegistry.completed = { 0: true };
  }

  orderRegistry.started += 1;
  orderId = orderRegistry.started;
  // console.log('New orderId: ' + orderId);

  const orderCallback = ((isCatch, payload) => {
    // console.log('orderId: ' + orderId +
    //  ', pendingCompletion: ' + Object.keys(orderRegistry.pendingCompletion) +
    //  ', completed: ' + Object.keys(orderRegistry.completed));

    if ((orderId - 1) in orderRegistry.completed) {
      // console.log('Running: ' + orderId);
      orderRegistry.completed[orderId] = true;
      delete orderRegistry.pendingCompletion[orderId];

      const keys = Object.keys(orderRegistry.pendingCompletion);
      keys.sort((a, b) => (a - b));
      keys.map(k => {
        if ((k - 1) in orderRegistry.completed) {
          // console.log('Running: ' + k);
          orderRegistry.pendingCompletion[k]();
          orderRegistry.completed[k] = true;
          delete orderRegistry.pendingCompletion[k];
        }
      });

      if (orderRegistry.started in orderRegistry.completed) {
        // console.log('Garbage collect');
        orderRegistry.started = 0;
        orderRegistry.completed = { 0: true };
      }

      if (isCatch)
        throw payload;
      else
        return payload;
    }

    const prom_1 = new Promise((accept, reject) => {
      orderRegistry.pendingCompletion[orderId] = (() =>
        (isCatch ? reject(payload) : accept(payload)));
    });

    return prom_1;
  });

  prom = prom.then(xhr => orderCallback(false, xhr));
  prom = prom.catch(e => orderCallback(true, e));

  return prom;
}

export default wbApplyPromiseOrdering;