//
// Copyright (C) Stanislaw Adaszewski, 2020
// Contact: s.adaszewski@gmail.com
// Website: https://adared.ch/wba
// License: GNU Affero General Public License, Version 3
//

const defaultOrderRegistry = {};

/* function notify(orderRegistry) {
  if (!('listeners' in orderRegistry))
    return;
  for (let k in orderRegistry.listeners) {
    orderRegistry.listeners[k](orderRegistry);
  }
} */

function cursorDecor() {
  let d = $('#cursor-decor');
  if (d.length === 1)
    return $(d[0]);
  d = $('<div id="cursor-decor" style="z-index: 10000; position: absolute; left: 10px; top: 10px;"> \
      <div class="progress" style="height: 8px;"> \
        <div class="progress-bar progress-bar-striped progress-bar-animated" \
          role="progressbar" aria-valuenow="100" aria-valuemin="0" \
          aria-valuemax="100" style="width: 32px;"></div> \
      </div> \
    </div>');
  $(document.body).append(d);
  let pageX = 0, pageY = 0, scrollX = 0, scrollY = 0;
  document.addEventListener('mousemove', e => {
    pageX = e.pageX;
    pageY = e.pageY;
    d.css({ left: (e.pageX + 16) + 'px', top: (e.pageY + 16) + 'px' })
    scrollX = window.scrollX;
    scrollY = window.scrollY;
  });
  document.addEventListener('scroll', e => {
    d.css({ left: (pageX + window.scrollX - scrollX + 16) + 'px',
      top: (pageY + window.scrollY - scrollY + 16) + 'px' });
  });
  return d;
}

function updateCursorDecor(orderRegistry) {
  const d = cursorDecor();
  if (Object.keys(orderRegistry.pendingCompletion).length === 0)
    d.hide();
  else
    d.show();
}

function wbApplyPromiseOrdering(prom, orderRegistry) {
  let orderId;

  if (!orderRegistry)
    orderRegistry = defaultOrderRegistry;

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

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

  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 };
        cursorDecor().hide();
      }

      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;