import ICAL from 'ical.js';

const calendarIds = [
  "5WrcagPPARQ3BD87",
  "TFEAKjAgNFQZpNjo"
];

function mkCalendarUrl(id) {
  return `/cal/${id}/?export&accept=jcal`;
}

function fetchCalendar(id) {
  return fetch(mkCalendarUrl(id), { credentials: 'omit' }).then(resp => resp.json()).catch(err => console.error(err));
}

class Calendar {
  constructor (calendar) {
    this.calName = calendar[1][3][3];
    this.events = calendar[2].filter(item => item[0] === 'vevent').map(item => this._parse_vevent(item[1]));
  }

  _parse_vevent(vevent) {
    const event = {};
    vevent.forEach(elt => {
      event[elt[0]] = elt[3];
    });
    return event;
  }
}

function mkEventsFromCalendar(id) {
  return fetchCalendar(id).then(calendar => {
    if (calendar[0] !== 'vcalendar') return;
    const cal = new Calendar(calendar)
    return cal.events.map(evt => ({ title: evt.summary, start: new Date(evt.dtstart), end: new Date(evt.dtend) }))
  });
}

export function mkEvent(title, start, duration, ...rest) {
  start = new Date(start)
  const end = new Date(start)
  end.setMinutes(start.getMinutes() + duration)
  return {
    title,
    start,
    end,
    ...rest
  }
}

export function refreshEvents() {
  return Promise.all(calendarIds.map(mkEventsFromCalendar))
}