"use strict";

var _shallowEqual = _interopRequireDefault(require("fbjs/lib/shallowEqual"));

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/* eslint-disable import/no-extraneous-dependencies */
// $FlowIgnore

/**
 * @todo - horrible
 */
const getMonitorState = (props, monitorProps) => monitorProps.reduce((acc, cur) => {
  const dotNot = cur.split('.');

  if (dotNot.length > 1) {
    const obj = props[dotNot[0]];

    const _dotNot$reduce = dotNot.reduce((a, c) => Object.assign({}, a, {
      path: a.path.concat(`${a.path !== '' ? '.' : ''}${c}`),
      value: typeof obj === 'object' && typeof obj[c] !== 'undefined' ? obj[c] : null,
      obj: typeof obj === 'object' && typeof obj[c] === 'object' ? obj[c] : null
    }), {
      path: '',
      value: null,
      obj
    }),
          path = _dotNot$reduce.path,
          value = _dotNot$reduce.value;

    return Object.assign(acc, {
      [path]: value
    });
  }

  return Object.assign(acc, {
    [cur]: props[cur]
  });
}, {});

module.exports = function workAgainForMonitoredProps(monitorProps) {
  const validArgs = monitorProps && Array.isArray(monitorProps) && monitorProps.length > 0;

  if (!validArgs) {
    throw new Error('You must provide at least one prop for the workAgainForMonitoredProps');
  }

  let monitorState = null;
  return (prevProps, nextProps) => {
    if (monitorState === null) {
      // This is likely the first time the "shouldWorkAgain" is being hit.
      // Lets initialise our monitor state with the previous props.
      monitorState = getMonitorState(prevProps, monitorProps);
    }

    const prevState = monitorState;
    monitorState = getMonitorState(nextProps, monitorProps);
    return prevState === null || !(0, _shallowEqual.default)(prevState, monitorState);
  };
};