module.exports = function(RED){
  const dav = require('dav')
  const IcalExpander = require('ical-expander')
  const moment = require('moment')
  const https = require('https')

    function NextcloudCalDav (config) {
        RED.nodes.createNode(this, config)
        this.server = RED.nodes.getNode(config.server)
        this.calendar = config.calendar
        this.pastWeeks = config.pastWeeks || 0
        this.futureWeeks = config.futureWeeks || 4
        const node = this
    
        node.on('input', (msg) => {
          let startDate = moment().startOf('day').subtract(this.pastWeeks, 'weeks')
          let endDate = moment().endOf('day').add(this.futureWeeks, 'weeks')
          const filters = [{
            type: 'comp-filter',
            attrs: { name: 'VCALENDAR' },
            children: [{
              type: 'comp-filter',
              attrs: { name: 'VEVENT' },
              children: [{
                type: 'time-range',
                attrs: {
                  start: startDate.format('YYYYMMDD[T]HHmmss[Z]'),
                  end: endDate.format('YYYYMMDD[T]HHmmss[Z]')
                }
              }]
            }]
          }]
          // dav.debug.enabled = true;
          const xhr = new dav.transport.Basic(
            new dav.Credentials({
              username: node.server.credentials.user,
              password: node.server.credentials.pass
            })
          )
          // Server + Basepath
          let calDavUri = node.server.address + '/remote.php/dav/calendars/'
          // User
          calDavUri += node.server.credentials.user + '/'
          dav.createAccount({ server: calDavUri, xhr: xhr, loadCollections: true, loadObjects: true })
            .then(function (account) {
              if (!account.calendars) {
                node.error('Nextcloud:CalDAV -> no calendars found.')
                return
              }
              // account instanceof dav.Account
              account.calendars.forEach(function (calendar) {
                // Wenn Kalender gesetzt ist, dann nur diesen abrufen
                let calName = msg.calendar || node.calendar
                if (!calName || !calName.length || (calName && calName.length && calName === calendar.displayName)) {
                  dav.listCalendarObjects(calendar, { xhr: xhr, filters: filters })
                    .then(function (calendarEntries) {
                      let msg = { 'payload': { 'name': calendar.displayName, 'data': [] } }
                      calendarEntries.forEach(function (calendarEntry) {
                        try {
                          const ics = calendarEntry.calendarData
                          const icalExpander = new IcalExpander({ ics, maxIterations: 100 })
                          const events = icalExpander.between(startDate.toDate(), endDate.toDate())
                          msg.payload.data = msg.payload.data.concat(convertEvents(events))
                        } catch (error) {
                          node.error('Error parsing calendar data: ' + error)
                        }
                      })
                      node.send(msg)
                    }, function () {
                      node.error('Nextcloud:CalDAV -> get ics went wrong.')
                    })
                }
              })
            }, function () {
              node.error('Nextcloud:CalDAV -> get calendars went wrong.')
            })
        })
    
        function convertEvents (events) {
          const mappedEvents = events.events.map(_convertEvent)
          const mappedOccurrences = events.occurrences.map(_convertEvent)
          return [].concat(mappedEvents, mappedOccurrences)
        }
    
        function _convertEvent (e) {
          if (e) {
            let startDate = e.startDate.toString()
            let endDate = e.endDate.toString()
    
            if (e.item) {
              e = e.item
            }
            if (e.duration.wrappedJSObject) {
              delete e.duration.wrappedJSObject
            }
    
            return {
              startDate: startDate,
              endDate: endDate,
              summary: e.summary || '',
              description: e.description || '',
              attendees: e.attendees,
              duration: e.duration.toICALString(),
              durationSeconds: e.duration.toSeconds(),
              location: e.location || '',
              organizer: e.organizer || '',
              uid: e.uid || '',
              isRecurring: false,
              allDay: ((e.duration.toSeconds() % 86400) === 0)
            }
          }
        }
      }
      RED.nodes.registerType('nextcloud-caldav', NextcloudCalDav)
}