import { StoreState } from 'app/common/store/store.types';
import moment from 'moment';
import { createSelector } from 'reselect';
import { CalendarEvent } from './calendar.types';
import { getLoadingStatus } from '../../../shared/modules/loading/getStatus';

const getCalendarStateSlice = (state: StoreState) => state.calendar;

export const selectCalendarEvents = (state: StoreState) => getCalendarStateSlice(state).events;

export const createCalendarIsLoadingSelector = (calendarFetchCollectionSelector) => (state) =>
  getLoadingStatus(calendarFetchCollectionSelector)(state);

export const selectSortedEvents = createSelector(
  selectCalendarEvents,
  calendarEvents => {
    const sortedEvents = calendarEvents.reduce(([past, upcoming]: CalendarEvent[][], event) => {
      return moment().isAfter(moment(event.date)) ? [[...past, event], upcoming] : [past, [...upcoming, event]];
    }, [[], []]);
    const [past, upcoming] = sortedEvents;

    past.sort((a, b) =>
      moment(b.date).isBefore(moment(a.date)) ? -1 : 1);
    upcoming.sort((a, b) =>
      moment(b.date).isBefore(moment(a.date)) ? 1 : -1);

    return {
      upcomingEvents: upcoming,
      pastEvents: past,
    };
  }
);