import 'package:hiddingsel_app/appflow/controller/network/calendar.dart';
import 'package:hiddingsel_app/appflow/model/event.dart';
import 'package:hiddingsel_app/appflow/model/event_organisations.dart';

import '../../constants/constant.dart';
import '../../services/storage.dart';
import '../../todo/scheduled_notification.dart';

class EventController {

  static int defaultSortCompare(EventModel a, EventModel b) => a.schedule.startTime.compareTo(b.schedule.startTime);

  static Stream<List<EventModel>> getEventListStream({int Function(EventModel, EventModel) sortCompare = defaultSortCompare}) async* {
    List<EventModel> yieldEvents = [];
    List<EventModel> allEvents = [];
    List<EventModel> newEvents = [];
    List<EventModel> organisationEvents = [];
    List<EventModel> savedEvents = await DataConnector.getJsonEncodableList<
        EventModel>(SystemStrings.dataEvents, [], EventModel.fromJson);
    yield yieldEvents = yieldEvents..addAll(savedEvents)..sort(sortCompare);

    for (EventOrganisationModel eventOrganisation in EventOrganisationModel.values){
      organisationEvents = await CalendarController
          .getOrganisationEvents(eventOrganisation);
      newEvents = organisationEvents.where((a) => !yieldEvents.contains(a)).toList();
      if (newEvents.isNotEmpty) {
        yield yieldEvents
          ..addAll(newEvents)
          ..sort(sortCompare);
      }
      allEvents = allEvents..addAll(organisationEvents)..sort(sortCompare);
    }
    DataConnector.saveJsonEncodable(SystemStrings.dataEvents, allEvents);
  }

  static Future<void> scheduleNotificationsBySettings() async {
    List<EventOrganisationModel> notifiableOrganisations = await _getNotifiableOrganisations();
    final duration = Duration(milliseconds: await SettingsConnector.getInt(SystemStrings.keyAlertTime, 1*60*60*1000));
    await ScheduledNotificationConnector.cancelAllScheduledNotification();
    EventController.getEventListStream().forEach((List<EventModel> list) async{
      var eventsToSchedule = list
          .where((e) => e.schedule.startTime.isAfter(DateTime.now()))
          .where((e) => notifiableOrganisations.any((o) => e.eventOrganizer.contains(o)))
          .toList();
      _scheduleNotifications(eventsToSchedule, duration);
    });
  }

  static _getNotifiableOrganisations() async {
    var notifiableOrganisations = List<EventOrganisationModel>.empty(growable: true);
    for (EventOrganisationModel event in EventOrganisationModel.values) {
      if(await event.eventNotificationAllowed) notifiableOrganisations.add(event);
    }
    return notifiableOrganisations;
  }

  static _scheduleNotifications(List<EventModel> eventsToSchedule,
      Duration duration) {
    eventsToSchedule.sort((a, b) => a.schedule.startTime.compareTo(b.schedule.startTime));
    Future.forEach(eventsToSchedule.take(50), (EventModel element) async {
      ScheduledNotificationConnector.scheduleNotification(
          element.id.hashCode,
          element.schedule.startTime.subtract(duration),
          element.name,
          '${element.eventOrganizer.first.name} - Der Termin beginnt bald.');
    });
  }
}