import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:syncfusion_flutter_calendar/calendar.dart';

import '../../../api/webuntis/queries/getHolidays/getHolidaysResponse.dart';
import '../../../api/webuntis/queries/getTimetable/getTimetableResponse.dart';
import '../../../extensions/dateTime.dart';
import '../../../model/timetable/timetableProps.dart';
import '../../../storage/base/settingsProvider.dart';
import 'appointmenetComponent.dart';
import 'appointmentDetails.dart';
import 'arbitraryAppointment.dart';
import 'customTimetableColors.dart';
import 'timeRegionComponent.dart';
import 'timetableEvents.dart';
import 'timetableNameMode.dart';

class Calendar extends StatefulWidget {
  final CalendarController controller;
  final TimetableProps timetableProps;
  final SettingsProvider settings;
  final bool isHomeWidget;
  const Calendar({super.key, required this.controller, required this.timetableProps, required this.settings, this.isHomeWidget = false});

  @override
  State<Calendar> createState() => _CalendarState();
}

class _CalendarState extends State<Calendar> {
  @override
  Widget build(BuildContext context) {
    var holidays = widget.timetableProps.getHolidaysResponse;
    return SfCalendar(
      timeZone: 'W. Europe Standard Time',
      view: widget.isHomeWidget ? CalendarView.day : CalendarView.workWeek,
      dataSource: _buildTableEvents(widget.timetableProps),

      maxDate: DateTime.now().add(const Duration(days: 7)).nextWeekday(DateTime.saturday),
      minDate: DateTime.now().subtract(const Duration (days: 14)).nextWeekday(DateTime.sunday),

      controller: widget.controller,

      onViewChanged: (ViewChangedDetails details) {
        if(widget.isHomeWidget) return;
        WidgetsBinding.instance.addPostFrameCallback((timeStamp) {
          Provider.of<TimetableProps>(context, listen: false).updateWeek(details.visibleDates.first, details.visibleDates.last);
        });
      },

      onTap: (calendarTapDetails) {
        if(calendarTapDetails.appointments == null) return;
        Appointment tapped = calendarTapDetails.appointments!.first;
        AppointmentDetails.show(context, widget.timetableProps, tapped);
      },

      firstDayOfWeek: DateTime.monday,
      specialRegions: _buildSpecialTimeRegions(holidays),
      timeSlotViewSettings: TimeSlotViewSettings(
        startHour: widget.isHomeWidget ? 08 : 07.5,
        endHour: widget.isHomeWidget ? 16 : 16.5,
        timeInterval: Duration(minutes: 30),
        timeFormat: 'HH:mm',
        dayFormat: 'EE',
        timeIntervalHeight: 40,
      ),

      timeRegionBuilder: (BuildContext context, TimeRegionDetails timeRegionDetails) => TimeRegionComponent(details: timeRegionDetails),
      appointmentBuilder: (BuildContext context, CalendarAppointmentDetails details) => AppointmentComponent(
        details: details,
        crossedOut: _isCrossedOut(details)
      ),

      headerHeight: 0,
      selectionDecoration: const BoxDecoration(),

      allowAppointmentResize: false,
      allowDragAndDrop: false,
      allowViewNavigation: false,
    );
  }

  List<TimeRegion> _buildSpecialTimeRegions(GetHolidaysResponse holidays) {
    var lastMonday = DateTime.now().subtract(const Duration(days: 14)).nextWeekday(DateTime.monday);
    var firstBreak = lastMonday.copyWith(hour: 10, minute: 15);
    var secondBreak = lastMonday.copyWith(hour: 13, minute: 50);

    var holidayList = holidays.result.map((holiday) {
      var startDay = _parseWebuntisTimestamp(holiday.startDate, 0);
      var dayCount = _parseWebuntisTimestamp(holiday.endDate, 0)
          .difference(startDay)
          .inDays;
      var days = List<DateTime>.generate(dayCount, (index) => startDay.add(Duration(days: index)));

      return days.map((holidayDay) => TimeRegion(
          startTime: holidayDay.copyWith(hour: 07, minute: 55),
          endTime: holidayDay.copyWith(hour: 16, minute: 30),
          text: 'holiday:${holiday.name}',
          color: Theme
              .of(context)
              .disabledColor
              .withAlpha(50),
          iconData: Icons.holiday_village_outlined
      ));
    }).expand((e) => e);

    bool isInHoliday(DateTime time) => holidayList.any((element) => element.startTime.isSameDay(time));

    return [
      ...holidayList,

      if(!isInHoliday(firstBreak))
        TimeRegion(
            startTime: firstBreak,
            endTime: firstBreak.add(const Duration(minutes: 20)),
            recurrenceRule: 'FREQ=DAILY;INTERVAL=1',
            text: 'centerIcon',
            color: Theme.of(context).primaryColor.withAlpha(50),
            iconData: Icons.restaurant
        ),

      if(!isInHoliday(secondBreak))
        TimeRegion(
            startTime: secondBreak,
            endTime: secondBreak.add(const Duration(minutes: 15)),
            recurrenceRule: 'FREQ=DAILY;INTERVAL=1',
            text: 'centerIcon',
            color: Theme.of(context).primaryColor.withAlpha(50),
            iconData: Icons.restaurant
        ),
    ];
  }

  List<GetTimetableResponseObject> _removeDuplicates(TimetableProps data, Duration maxTimeBetweenDouble) {

    var timetableList = data.getTimetableResponse.result.toList();

    if(timetableList.isEmpty) return timetableList;

    timetableList.sort((a, b) => _parseWebuntisTimestamp(a.date, a.startTime).compareTo(_parseWebuntisTimestamp(b.date, b.startTime)));

    var previousElement = timetableList.first;
    for(var i = 1; i < timetableList.length; i++) {
      var currentElement = timetableList.elementAt(i);

      bool isSameLesson() {
        var currentSubjectId = currentElement.su.firstOrNull?.id;
        var previousSubjectId = previousElement.su.firstOrNull?.id;

        if(currentSubjectId == null || previousSubjectId == null || currentSubjectId != previousSubjectId) return false;

        var currentRoomId = currentElement.ro.firstOrNull?.id;
        var previousRoomId = previousElement.ro.firstOrNull?.id;

        if(currentRoomId != previousRoomId) return false;

        var currentTeacherId = currentElement.te.firstOrNull?.id;
        var previousTeacherId = previousElement.te.firstOrNull?.id;

        if(currentTeacherId != previousTeacherId) return false;

        var currentStatusCode = currentElement.code;
        var previousStatusCode = previousElement.code;

        if(currentStatusCode != previousStatusCode) return false;

        return true;
      }

      bool isNotSeparated() => _parseWebuntisTimestamp(previousElement.date, previousElement.endTime).add(maxTimeBetweenDouble)
          .isSameOrAfter(_parseWebuntisTimestamp(currentElement.date, currentElement.startTime));

      if(isSameLesson() && isNotSeparated()) {
        previousElement.endTime = currentElement.endTime;
        timetableList.remove(currentElement);
        i--;
      } else {
        previousElement = currentElement;
      }
    }

    return timetableList;
  }

  TimetableEvents _buildTableEvents(TimetableProps data) {

    var timetableList = data.getTimetableResponse.result.toList();

    if(widget.settings.val().timetableSettings.connectDoubleLessons) {
      timetableList = _removeDuplicates(data, const Duration(minutes: 5));
    }

    var appointments = timetableList.map((element) {

      var rooms = data.getRoomsResponse;
      var subjects = data.getSubjectsResponse;

      try {
        var startTime = _parseWebuntisTimestamp(element.date, element.startTime);
        var endTime = _parseWebuntisTimestamp(element.date, element.endTime);

        var subject = subjects.result.firstWhere((subject) => subject.id == element.su[0].id);
        var subjectName = {
          TimetableNameMode.name: subject.name,
          TimetableNameMode.longName: subject.longName,
          TimetableNameMode.alternateName: subject.alternateName,
        }[widget.settings.val().timetableSettings.timetableNameMode];


        return Appointment(
          id: ArbitraryAppointment(webuntis: element),
          startTime: startTime,
          endTime: endTime,
          subject: subjectName!,
          location: ''
              '${rooms.result.firstWhere((room) => room.id == element.ro[0].id).name}'
              '\n'
              '${element.te.first.longname}',
          notes: element.activityType,
          color: _getEventColor(element, startTime, endTime),
        );
      } catch(e) {
        var endTime = _parseWebuntisTimestamp(element.date, element.endTime);
        return Appointment(
          id: ArbitraryAppointment(webuntis: element),
          startTime: _parseWebuntisTimestamp(element.date, element.startTime),
          endTime: endTime,
          subject: 'Änderung',
          notes: element.info,
          location: 'Unbekannt',
          color: endTime.isBefore(DateTime.now()) ? Theme.of(context).primaryColor.withAlpha(100) : Theme.of(context).primaryColor,
          startTimeZone: '',
          endTimeZone: '',
        );
      }
    }).toList();

    appointments.addAll(data.getCustomTimetableEventResponse.events.map((customEvent) => Appointment(
      id: ArbitraryAppointment(custom: customEvent),
      startTime: customEvent.startDate,
      endTime: customEvent.endDate,
      location: customEvent.description,
      subject: customEvent.title,
      recurrenceRule: customEvent.rrule,
      color: TimetableColors.getColorFromString(customEvent.color ?? TimetableColors.defaultColor.name),
      startTimeZone: '',
      endTimeZone: '',
    )));

    return TimetableEvents(appointments);
  }

  DateTime _parseWebuntisTimestamp(int date, int time) {
    var timeString = time.toString().padLeft(4, '0');
    return DateTime.parse('$date ${timeString.substring(0, 2)}:${timeString.substring(2, 4)}');
  }

  Color _getEventColor(GetTimetableResponseObject webuntisElement, DateTime startTime, DateTime endTime) {
    // Make element darker, when it already took place
    var alpha = endTime.isBefore(DateTime.now()) ? 100 : 255;

    // Cancelled
    if(webuntisElement.code == 'cancelled') return const Color(0xff000000).withAlpha(alpha);

    // Any changes or no teacher at this element
    if(webuntisElement.code == 'irregular' || webuntisElement.te.first.id == 0) return const Color(0xff8F19B3).withAlpha(alpha);

    // Teacher has changed
    if(webuntisElement.te.any((element) => element.orgname != null)) return const Color(0xFF29639B).withAlpha(alpha);

    // Event was in the past
    if(endTime.isBefore(DateTime.now())) return Theme.of(context).primaryColor.withAlpha(alpha);

    // Event takes currently place
    if(endTime.isAfter(DateTime.now()) && startTime.isBefore(DateTime.now())) return Theme.of(context).primaryColor.withRed(200);

    // Fallback
    return Theme.of(context).primaryColor.withAlpha(alpha);
  }

  bool _isCrossedOut(CalendarAppointmentDetails calendarEntry) {
    var appointment = calendarEntry.appointments.first.id as ArbitraryAppointment;
    if(appointment.hasWebuntis()) {
      return appointment.webuntis!.code == 'cancelled';
    }
    return false;
  }
}