meincantor-app/lib/dashboard.dart

// GCG.MeinCantor - Die Schulplattform für Cantorianer.
// Copyright (C) 2021-2022 Georg-Cantor-Gymnasium Halle (Saale)

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.

// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

import 'dart:convert';
import 'dart:math';

import 'package:background_fetch/background_fetch.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import 'package:meincantor/background_fetch.dart';
import 'package:meincantor/const.dart';
import 'package:meincantor/schuelerzeitung.dart';
import 'package:meincantor/Settings/dashboard.dart';

import 'package:meincantor/main.dart';
import 'package:meincantor/networking.dart';
import 'package:meincantor/login.dart';

import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:intl/intl.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:material_design_icons_flutter/material_design_icons_flutter.dart';
import 'package:http/http.dart' as http;

import 'package:meincantor/news.dart';

Future<String> getSettingsString(String key) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  String? value = prefs.getString(key);
  if (value == null || value.isEmpty) {
    value = "";
  }
  return value;
}

Widget buildSettingsString(String key, TextStyle? style) {
  return FutureBuilder(
      future: getSettingsString(key),
      builder: (context, snapshot) {
        if (snapshot.hasData) {
          return Text(snapshot.data as String, style: style);
        } else {
          return const SizedBox.shrink();
        }
      });
}

Future<List<String>> getFavClasses() async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  List<String>? listJson = prefs.getStringList("favClasses");
  if (listJson == null || listJson.isEmpty) {
    return <String>[];
  } else {
    return listJson;
  }
}

List<Widget> buildFavClasses(
    BuildContext context, List<String> favClasses, Function removeFavClass) {
  if (favClasses.isEmpty) {
    return [const SizedBox.shrink()];
  } else {
    List<Widget> list = [];
    for (var element in favClasses) {
      var card = SizedBox(
        width: 170,
        child: GestureDetector(
          onTap: () async {
            Navigator.push(
                context,
                MaterialPageRoute(
                    builder: (context) => DefaultTabController(
                        initialIndex: 0,
                        length: 3,
                        child: Scaffold(
                          appBar: AppBar(
                            leading: null,
                            elevation: 0,
                            title: Text("Klasse $element"),
                            bottom: const TabBar(
                              indicatorColor: Palette.accent,
                              enableFeedback: true,
                              indicatorPadding: EdgeInsets.all(5),
                              indicatorSize: TabBarIndicatorSize.label,
                              tabs: <Widget>[
                                Tab(
                                  text: "Heute",
                                  icon: Icon(Icons.calendar_today_outlined),
                                ),
                                Tab(
                                  text: "Morgen",
                                  icon: Icon(MdiIcons.calendarToday),
                                ),
                                Tab(
                                  text: "Neuster Plan",
                                  icon: Icon(Icons.calendar_view_day_outlined),
                                ),
                              ],
                            ),
                          ),
                          body: TabBarView(
                            children: <Widget>[
                              LayoutBuilder(builder: (context, constraints) {
                                double widgetWidth = constraints.maxWidth;

                                int factor;

                                if (widgetWidth <= 600) {
                                  factor = 1;
                                } else if (widgetWidth <= 1400) {
                                  factor = 2;
                                } else if (widgetWidth <= 2000) {
                                  factor = 3;
                                } else {
                                  factor = 1;
                                }

                                return Center(
                                    heightFactor: 1,
                                    child: Container(
                                      constraints: BoxConstraints(
                                        maxWidth:
                                            MediaQuery.of(context).size.width /
                                                factor,
                                      ),
                                      child: buildTimetable(
                                          fetchClassTimetable(
                                              "/${DateFormat("yyyyMMdd").format(DateTime.now())}",
                                              element),
                                          "Vertretungsplan für heute"),
                                    ));
                              }),
                              LayoutBuilder(builder: (context, constraints) {
                                double widgetWidth = constraints.maxWidth;

                                int factor;

                                if (widgetWidth <= 600) {
                                  factor = 1;
                                } else if (widgetWidth <= 1400) {
                                  factor = 2;
                                } else if (widgetWidth <= 2000) {
                                  factor = 3;
                                } else {
                                  factor = 1;
                                }

                                return Center(
                                    heightFactor: 1,
                                    child: Container(
                                      constraints: BoxConstraints(
                                        maxWidth:
                                            MediaQuery.of(context).size.width /
                                                factor,
                                      ),
                                      child: buildTimetable(
                                          fetchClassTimetable(
                                              "/${DateFormat("yyyyMMdd").format(DateTime.now().add(const Duration(days: 1)))}",
                                              element),
                                          "Vertretungsplan für morgen"),
                                    ));
                              }),
                              LayoutBuilder(builder: (context, constraints) {
                                double widgetWidth = constraints.maxWidth;

                                int factor;

                                if (widgetWidth <= 600) {
                                  factor = 1;
                                } else if (widgetWidth <= 1400) {
                                  factor = 2;
                                } else if (widgetWidth <= 2000) {
                                  factor = 3;
                                } else {
                                  factor = 1;
                                }

                                return Center(
                                    heightFactor: 1,
                                    child: Container(
                                        constraints: BoxConstraints(
                                          maxWidth: MediaQuery.of(context)
                                                  .size
                                                  .width /
                                              factor,
                                        ),
                                        child: buildTimetable(
                                            fetchClassTimetable(
                                                "/latest", element),
                                            "aktueller Vertretungsplan")));
                              }),
                            ],
                          ),
                        ))));
          },
          onLongPress: () async {
            SharedPreferences prefs = await SharedPreferences.getInstance();
            List<String> stringList = prefs.getStringList("favClasses")!;
            stringList.remove(element);
            prefs.setStringList("favClasses", stringList);
            removeFavClass(element);
          },
          child: Card(
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(10),
            ),
            child: Container(
                decoration: BoxDecoration(
                    borderRadius: BorderRadius.circular(10),
                    gradient: LinearGradient(
                      begin: Alignment.topRight,
                      end: Alignment.bottomLeft,
                      colors: [
                        Colors.primaries[
                            Random().nextInt(Colors.primaries.length)],
                        Colors.primaries[
                            Random().nextInt(Colors.primaries.length)],
                      ],
                    )),
                child: Padding(
                  padding: const EdgeInsets.all(10),
                  child: Center(
                    child: Padding(
                      padding: const EdgeInsets.fromLTRB(15, 15, 15, 15),
                      child: Text(
                        element,
                        style: const TextStyle(color: Colors.white),
                        textScaleFactor: 2.0,
                      ),
                    ),
                  ),
                )),
          ),
        ),
      );
      list.add(card);
    }
    return (list);
  }
}

class Dashboard extends StatefulWidget {
  const Dashboard({Key? key, this.restorationId}) : super(key: key);

  final String? restorationId;

  @override
  State<StatefulWidget> createState() => _DashboardState();
}

class _DashboardState extends State<Dashboard> with RestorationMixin {
  final RestorableInt _currentIndex = RestorableInt(0);

  @override
  void initState() {
    super.initState();
    initPlatformState();
    initNotifications();
  }

  Future<void> initNotifications() async {
    FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
        FlutterLocalNotificationsPlugin();
    // initialise the plugin. app_icon needs to be a added as a drawable resource to the Android head project
    const AndroidInitializationSettings initializationSettingsAndroid =
        AndroidInitializationSettings('app_icon');
    const DarwinInitializationSettings initializationSettingsDarwin =
        DarwinInitializationSettings();
    const InitializationSettings initializationSettings =
        InitializationSettings(
            android: initializationSettingsAndroid,
            iOS: initializationSettingsDarwin,
            macOS: initializationSettingsDarwin);
    await flutterLocalNotificationsPlugin.initialize(initializationSettings,
        onSelectNotification: selectNotification);
  }

  void selectNotification(String? payload) async {
    if (payload == null) {
      debugPrint('notification payload: $payload');
    } else if (payload == "today") {
      await Navigator.push(
        context,
        MaterialPageRoute<void>(
            builder: (context) => Scaffold(
                appBar: AppBar(title: const Text("Vertretungsplan für heute")),
                body: buildTimetable(
                    fetchClassTimetable(
                        "/${DateFormat("yyyyMMdd").format(DateTime.now())}",
                        null),
                    "Vertretungsplan für heute"))),
      );
    } else if (payload == "tomorrow") {
      await Navigator.push(
        context,
        MaterialPageRoute<void>(
            builder: (context) => Scaffold(
                appBar: AppBar(title: const Text("Vertretungsplan für morgen")),
                body: buildTimetable(
                    fetchClassTimetable(
                        "/${DateFormat("yyyyMMdd").format(DateTime.now().add(const Duration(days: 1)))}",
                        null),
                    "Vertretungsplan für morgen"))),
      );
    } else if (payload == "sz") {
      await Navigator.push(
        context,
        MaterialPageRoute<void>(
            builder: (context) => const SZ()),
      );
    } else if (payload == "articles") {
      await Navigator.push(
        context,
        MaterialPageRoute<void>(
            builder: (context) => const News()),
      );
    }
  }

  Future<void> initPlatformState() async {
    // Configure BackgroundFetch.
    int status = await BackgroundFetch.configure(
        BackgroundFetchConfig(
            minimumFetchInterval: 15,
            stopOnTerminate: false,
            enableHeadless: true,
            startOnBoot: true,
            requiresBatteryNotLow: false,
            requiresCharging: false,
            requiresStorageNotLow: false,
            requiresDeviceIdle: false,
            requiredNetworkType: NetworkType.ANY), (String taskId) async {
      // <-- Event handler
      // This is the fetch-event callback.
      print("[BackgroundFetch] Event received $taskId");

      await backgroundFetchTimetable();
      await backgroundFetchArticles();

      // IMPORTANT:  You must signal completion of your task or the OS can punish your app
      // for taking too long in the background.
      BackgroundFetch.finish(taskId);
    }, (String taskId) async {
      // <-- Task timeout handler.
      // This task has exceeded its allowed running-time.  You must stop what you're doing and immediately .finish(taskId)
      print("[BackgroundFetch] TASK TIMEOUT taskId: $taskId");
      BackgroundFetch.finish(taskId);
    });
    print('[BackgroundFetch] configure success: $status');

    // If the widget was removed from the tree while the asynchronous platform
    // message was in flight, we want to discard the reply rather than calling
    // setState to update our non-existent appearance.
    if (!mounted) return;
  }

  @override
  Widget build(BuildContext context) {
    var bottomNavBarItems = [
      const BottomNavigationBarItem(
        icon: Icon(MdiIcons.homeOutline),
        label: "Startseite",
      ),
      const BottomNavigationBarItem(
          icon: Icon(MdiIcons.timetable), label: "Vertretungsplan"),
    ];
    return Scaffold(
      body: _DashboardBottomNavView(
          key: UniqueKey(), item: bottomNavBarItems[_currentIndex.value]),
      bottomNavigationBar: BottomNavigationBar(
        showUnselectedLabels: false,
        items: bottomNavBarItems,
        currentIndex: _currentIndex.value,
        onTap: (index) {
          setState(() {
            _currentIndex.value = index;
          });
        },
      ),
    );
  }

  @override
  String? get restorationId => widget.restorationId;

  @override
  void restoreState(RestorationBucket? oldBucket, bool initialRestore) {
    registerForRestoration(_currentIndex, 'bottom_navigation_tab_index');
  }
}

class _DashboardBottomNavView extends StatefulWidget {
  const _DashboardBottomNavView({Key? key, required this.item})
      : super(key: key);
  final BottomNavigationBarItem item;

  @override
  // ignore: no_logic_in_create_state
  State<StatefulWidget> createState() => _DashboardBottomNavViewState(item);
}

class _DashboardBottomNavViewState extends State<_DashboardBottomNavView> {
  final BottomNavigationBarItem item;
  _DashboardBottomNavViewState(this.item);

  List<String> favClasses = [];

  void removeFavClass(String classNum) {
    setState(() {
      favClasses.remove(classNum);
    });
  }

  @override
  Widget build(BuildContext context) {
    final drawerElements = ListView(
      children: [
        UserAccountsDrawerHeader(
            accountName: buildSettingsString('name', const TextStyle()),
            accountEmail: buildSettingsString('email', const TextStyle()),
            currentAccountPicture: FutureBuilder(
              future: Future.sync(() async {
                SharedPreferences prefs = await SharedPreferences.getInstance();
                String? user = prefs.getString("user");
                if (user == null || user.isEmpty) {
                  user = "";
                }
                String? name = prefs.getString("name");
                if (name == null || name.isEmpty) {
                  name = "";
                }
                Map data = {"user": user, "name": name};
                return data;
              }),
              builder: (context, snapshot) {
                if (snapshot.hasData) {
                  String url = "$avatarUrl/${(snapshot.data! as Map)['user']}";
                  return Container(
                      decoration: BoxDecoration(
                          shape: BoxShape.circle,
                          image: DecorationImage(
                              fit: BoxFit.scaleDown,
                              image: NetworkImage(url))));
                } else {
                  return const CircularProgressIndicator();
                }
              },
            )),
        Padding(
          padding: const EdgeInsets.all(5),
          child: ListTile(
            shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.circular(15.0)),
            title: const Text("Einstellungen"),
            onTap: () {
              Navigator.push(
                context,
                MaterialPageRoute(builder: (context) => const Settings()),
              );
            },
            leading: const Icon(Icons.settings_outlined),
          ),
        ),
        Padding(
          padding: const EdgeInsets.all(5),
          child: ListTile(
            shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.circular(15.0)),
            title: const Text("Abmelden"),
            onTap: () async {
              return showDialog<void>(
                context: context,
                barrierDismissible: false, // user must tap button!
                builder: (BuildContext context) {
                  return AlertDialog(
                    title: const Text('Abmelden'),
                    content: SingleChildScrollView(
                      child: ListBody(
                        children: const <Widget>[
                          Text(
                              'Dabei werden alle persönlichen Enstellungen gelöscht!'),
                        ],
                      ),
                    ),
                    actions: <Widget>[
                      TextButton(
                        child: const Text('Bestätigen'),
                        onPressed: () async {
                          SharedPreferences prefs =
                              await SharedPreferences.getInstance();
                          prefs.clear();
                          Navigator.pushReplacement(
                            context,
                            MaterialPageRoute(builder: (context) => Login()),
                          );
                        },
                      ),
                    ],
                  );
                },
              );
            },
            leading: const Icon(Icons.exit_to_app_outlined),
          ),
        ),
      ],
    );
    if (item.label == "Startseite") {
      double _timeOfDayToDouble(TimeOfDay tod) => tod.hour + tod.minute / 60.0;
      int lessonCount;
      _timeOfDayToDouble(TimeOfDay.now()) <=
              _timeOfDayToDouble(const TimeOfDay(hour: 7, minute: 30))
          ? lessonCount = 1
          : _timeOfDayToDouble(TimeOfDay.now()) > _timeOfDayToDouble(const TimeOfDay(hour: 7, minute: 30)) &&
                  _timeOfDayToDouble(TimeOfDay.now()) <=
                      _timeOfDayToDouble(const TimeOfDay(hour: 8, minute: 20))
              ? lessonCount = 2
              : _timeOfDayToDouble(TimeOfDay.now()) > _timeOfDayToDouble(const TimeOfDay(hour: 8, minute: 20)) &&
                      _timeOfDayToDouble(TimeOfDay.now()) <=
                          _timeOfDayToDouble(
                              const TimeOfDay(hour: 9, minute: 25))
                  ? lessonCount = 3
                  : _timeOfDayToDouble(TimeOfDay.now()) > _timeOfDayToDouble(const TimeOfDay(hour: 9, minute: 25)) &&
                          _timeOfDayToDouble(TimeOfDay.now()) <=
                              _timeOfDayToDouble(
                                  const TimeOfDay(hour: 10, minute: 15))
                      ? lessonCount = 4
                      : _timeOfDayToDouble(TimeOfDay.now()) >
                                  _timeOfDayToDouble(
                                      const TimeOfDay(hour: 10, minute: 15)) &&
                              _timeOfDayToDouble(TimeOfDay.now()) <=
                                  _timeOfDayToDouble(
                                      const TimeOfDay(hour: 11, minute: 30))
                          ? lessonCount = 5
                          : _timeOfDayToDouble(TimeOfDay.now()) > _timeOfDayToDouble(const TimeOfDay(hour: 11, minute: 30)) &&
                                  _timeOfDayToDouble(TimeOfDay.now()) <=
                                      _timeOfDayToDouble(
                                          const TimeOfDay(hour: 12, minute: 20))
                              ? lessonCount = 6
                              : _timeOfDayToDouble(TimeOfDay.now()) > _timeOfDayToDouble(const TimeOfDay(hour: 12, minute: 20)) &&
                                      _timeOfDayToDouble(TimeOfDay.now()) <=
                                          _timeOfDayToDouble(const TimeOfDay(
                                              hour: 13, minute: 30))
                                  ? lessonCount = 7
                                  : _timeOfDayToDouble(TimeOfDay.now()) > _timeOfDayToDouble(const TimeOfDay(hour: 13, minute: 30)) &&
                                          _timeOfDayToDouble(TimeOfDay.now()) <=
                                              _timeOfDayToDouble(const TimeOfDay(hour: 14, minute: 20))
                                      ? lessonCount = 8
                                      : _timeOfDayToDouble(TimeOfDay.now()) > _timeOfDayToDouble(const TimeOfDay(hour: 14, minute: 20)) && _timeOfDayToDouble(TimeOfDay.now()) <= _timeOfDayToDouble(const TimeOfDay(hour: 15, minute: 10))
                                          ? lessonCount = 9
                                          : _timeOfDayToDouble(TimeOfDay.now()) > _timeOfDayToDouble(const TimeOfDay(hour: 15, minute: 10)) && _timeOfDayToDouble(TimeOfDay.now()) <= _timeOfDayToDouble(const TimeOfDay(hour: 16, minute: 00))
                                              ? lessonCount = 10
                                              : lessonCount = -1;

      var view = SingleChildScrollView(
        child: Column(children: [
          Row(
            mainAxisSize: MainAxisSize.max,
            children: [
              Padding(
                padding: const EdgeInsets.fromLTRB(20, 30, 20, 5),
                child: Text(
                  'Hallo,',
                  style: GoogleFonts.robotoSlab(
                    fontSize: 20,
                  ),
                ),
              ),
            ],
          ),
          Row(
            mainAxisSize: MainAxisSize.max,
            children: [
              Padding(
                padding: const EdgeInsets.fromLTRB(20, 5, 20, 20),
                child: buildSettingsString(
                  "name",
                  GoogleFonts.robotoSlab(
                    fontSize: 28,
                    fontWeight: FontWeight.w800,
                  ),
                ),
              )
            ],
          ),
          Row(
            mainAxisSize: MainAxisSize.max,
            children: [
              Padding(
                padding: const EdgeInsets.fromLTRB(20, 10, 0, 10),
                child: Text(
                  'Deine nächste Unterrichtsstunde:',
                  style: GoogleFonts.robotoSlab(
                    fontSize: 20,
                    fontWeight: FontWeight.w100,
                  ),
                ),
              )
            ],
          ),
          Padding(
            padding: const EdgeInsets.fromLTRB(20, 20, 20, 10),
            child: buildTodayClassTimetableLesson(lessonCount),
          ),
          Padding(
            padding: const EdgeInsets.fromLTRB(20, 20, 20, 10),
            child: Wrap(
              children: [
                SizedBox(
                    width: 175,
                    child: GestureDetector(
                      onTap: () async {
                        Navigator.push(
                          context,
                          MaterialPageRoute(builder: (context) => const SZ()),
                        );
                      },
                      child: Card(
                          shape: RoundedRectangleBorder(
                            borderRadius: BorderRadius.circular(10),
                          ),
                          child: const Padding(
                            padding: EdgeInsets.all(10),
                            child: ListTile(
                              title: Padding(
                                padding: EdgeInsets.fromLTRB(0, 0, 0, 10),
                                child: Icon(
                                  MdiIcons.newspaper,
                                  color: Palette.accent,
                                  size: 48,
                                ),
                              ),
                              subtitle: Center(
                                child: Padding(
                                  padding: EdgeInsets.fromLTRB(0, 10, 0, 0),
                                  child: Text('Schülerzeitung'),
                                ),
                              ),
                            ),
                          )),
                    )),
                SizedBox(
                  width: 175,
                  child: GestureDetector(
                    onTap: () async {
                      Navigator.push(
                        context,
                        MaterialPageRoute(builder: (context) => const News()),
                      );
                    },
                    child: Card(
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(10),
                        ),
                        child: const Padding(
                          padding: EdgeInsets.all(10),
                          child: ListTile(
                            title: Padding(
                              padding: EdgeInsets.fromLTRB(0, 0, 0, 10),
                              child: Icon(
                                MdiIcons.newspaperVariantOutline,
                                color: Palette.accent,
                                size: 48,
                              ),
                            ),
                            subtitle: Center(
                              child: Padding(
                                padding: EdgeInsets.fromLTRB(0, 10, 0, 0),
                                child: Text(
                                  'Aktuelles',
                                ),
                              ),
                            ),
                          ),
                        )),
                  ),
                )
              ],
            ),
          ),
          Padding(
              padding: const EdgeInsets.fromLTRB(20, 0, 20, 20),
              child: Column(
                children: [
                  const ListTile(title: Text("Favorisierte Klassen")),
                  FutureBuilder(
                      future: getFavClasses(),
                      builder: (context, snapshot) {
                        if (snapshot.hasData) {
                          favClasses = snapshot.data! as List<String>;
                          return Wrap(children: [
                            ...(buildFavClasses(
                                context, favClasses, removeFavClass)),
                            SizedBox(
                              width: 170,
                              child: GestureDetector(
                                onTap: () async {
                                  showModalBottomSheet<void>(
                                    isScrollControlled: true,
                                    shape: const RoundedRectangleBorder(
                                      borderRadius: BorderRadius.only(
                                          topLeft: Radius.circular(25.0),
                                          topRight: Radius.circular(25.0)),
                                    ),
                                    context: context,
                                    builder: (BuildContext context) {
                                      return SizedBox(
                                        height: 400,
                                        child: ListView(
                                          children: <Widget>[
                                            ListTile(
                                              title: const Text(
                                                  "Klasse hinzufügen",
                                                  style: TextStyle(
                                                      fontWeight:
                                                          FontWeight.bold)),
                                              leading:
                                                  const Icon(Icons.arrow_back),
                                              onTap: () {
                                                Navigator.of(context).pop();
                                              },
                                            ),
                                            FutureBuilder<http.Response>(
                                                future: fetchClassesList(),
                                                builder: (context, snapshot) {
                                                  if (snapshot.hasData) {
                                                    if (snapshot
                                                            .data!.statusCode ==
                                                        200) {
                                                      List<Widget> classesList =
                                                          [];
                                                      for (var classNum
                                                          in jsonDecode(snapshot
                                                              .data!.body)) {
                                                        classesList
                                                            .add(ListTile(
                                                          title: Text(classNum),
                                                          onTap: () async {
                                                            SharedPreferences
                                                                prefs =
                                                                await SharedPreferences
                                                                    .getInstance();
                                                            if (prefs
                                                                        .getStringList(
                                                                            "favClasses") !=
                                                                    null &&
                                                                prefs
                                                                    .getStringList(
                                                                        "favClasses")!
                                                                    .contains(
                                                                        classNum)) {
                                                              const snackBar = SnackBar(
                                                                  content: Text(
                                                                      'Klasse bereits in den Favoriten'));
                                                              ScaffoldMessenger
                                                                      .of(
                                                                          context)
                                                                  .showSnackBar(
                                                                      snackBar);
                                                            } else if (prefs
                                                                    .getStringList(
                                                                        "favClasses") ==
                                                                null) {
                                                              List<String>
                                                                  stringList = [
                                                                classNum
                                                              ];
                                                              prefs.setStringList(
                                                                  "favClasses",
                                                                  stringList);
                                                            } else {
                                                              List<String>
                                                                  stringList =
                                                                  prefs.getStringList(
                                                                      "favClasses")!;
                                                              stringList.add(
                                                                  classNum);
                                                              prefs.setStringList(
                                                                  "favClasses",
                                                                  stringList);
                                                              setState(() {
                                                                favClasses =
                                                                    stringList;
                                                              });
                                                            }
                                                          },
                                                        ));
                                                        classesList.add(
                                                            const Divider());
                                                      }
                                                      return Column(
                                                          children:
                                                              classesList);
                                                    } else if (snapshot
                                                            .data!.statusCode ==
                                                        500) {
                                                      return const Padding(
                                                        padding:
                                                            EdgeInsets.fromLTRB(
                                                                10, 10, 10, 10),
                                                        child: Center(
                                                            child: Text(
                                                                "Serverfehler. Bitte wende dich an den MeinCantor-Support.")),
                                                      );
                                                    } else if (snapshot
                                                            .data!.statusCode ==
                                                        404) {
                                                      return const Padding(
                                                        padding:
                                                            EdgeInsets.fromLTRB(
                                                                10, 10, 10, 10),
                                                        child: Center(
                                                            child: Text(
                                                                "Keine Verbindung mit dem MeinCantor-Server möglich. Bitte prüfe deine Internetverbindung und deine DNS-Einstellungen oder wende dich an den MeinCantor-Support")),
                                                      );
                                                    } else {
                                                      return const Center(
                                                          child: Text(
                                                              "Uups... etwas ist schief gelaufen..."));
                                                    }
                                                  } else if (snapshot
                                                      .hasError) {
                                                    return const Center(
                                                        child: Text(
                                                            "Uups... etwas ist schief gelaufen..."));
                                                  } else {
                                                    return const Center(
                                                        child:
                                                            CircularProgressIndicator());
                                                  }
                                                })
                                          ],
                                        ),
                                      );
                                    },
                                  );
                                },
                                child: Card(
                                    shape: RoundedRectangleBorder(
                                      borderRadius: BorderRadius.circular(10),
                                    ),
                                    child: const Padding(
                                      padding: EdgeInsets.all(6),
                                      child: ListTile(
                                        title: Center(child: Text("+")),
                                        subtitle: Center(
                                          child: Text(
                                            'Klasse hinzufügen',
                                            textScaleFactor: 0.9,
                                          ),
                                        ),
                                      ),
                                    )),
                              ),
                            )
                          ]);
                        } else if (snapshot.hasError) {
                          return const Center(
                              child:
                                  Text("Uups... etwas ist schief gelaufen..."));
                        } else {
                          return const CircularProgressIndicator();
                        }
                      }),
                ],
              ))
        ]),
      );
      return Scaffold(
        appBar: AppBar(
          title: const Text("GCG.MeinCantor"),
          centerTitle: true,
        ),
        drawer: Drawer(
          child: drawerElements,
        ),
        body: LayoutBuilder(builder: (context, constraints) {
          double widgetWidth = constraints.maxWidth;

          int factor;

          if (widgetWidth <= 600) {
            factor = 1;
          } else if (widgetWidth <= 1400) {
            factor = 2;
          } else if (widgetWidth <= 2000) {
            factor = 3;
          } else {
            factor = 1;
          }

          return Center(
            heightFactor: 1,
            child: Container(
                constraints: BoxConstraints(
                  maxWidth: MediaQuery.of(context).size.width / factor,
                ),
                child: view),
          );
        }),
      );
    } else if (item.label == "Vertretungsplan") {
      List<Widget> children = <Widget>[
        LayoutBuilder(builder: (context, constraints) {
          double widgetWidth = constraints.maxWidth;

          int factor;

          if (widgetWidth <= 600) {
            factor = 1;
          } else if (widgetWidth <= 1400) {
            factor = 2;
          } else if (widgetWidth <= 2000) {
            factor = 3;
          } else {
            factor = 1;
          }

          return Center(
            child: Container(
              constraints: BoxConstraints(
                maxWidth: MediaQuery.of(context).size.width / factor,
              ),
              child: buildTimetable(
                  fetchClassTimetable(
                      "/${DateFormat("yyyyMMdd").format(DateTime.now())}",
                      null),
                  "Vertretungsplan für heute"),
            ),
          );
        }),
        LayoutBuilder(builder: (context, constraints) {
          double widgetWidth = constraints.maxWidth;

          int factor;

          if (widgetWidth <= 600) {
            factor = 1;
          } else if (widgetWidth <= 1400) {
            factor = 2;
          } else if (widgetWidth <= 2000) {
            factor = 3;
          } else {
            factor = 1;
          }

          return Center(
            child: Container(
              constraints: BoxConstraints(
                maxWidth: MediaQuery.of(context).size.width / factor,
              ),
              child: buildTimetable(
                  fetchClassTimetable(
                      "/${DateFormat("yyyyMMdd").format(DateTime.now().add(const Duration(days: 1)))}",
                      null),
                  "Vertretungsplan für morgen"),
            ),
          );
        }),
        LayoutBuilder(builder: (context, constraints) {
          double widgetWidth = constraints.maxWidth;

          int factor;

          if (widgetWidth <= 600) {
            factor = 1;
          } else if (widgetWidth <= 1400) {
            factor = 2;
          } else if (widgetWidth <= 2000) {
            factor = 3;
          } else {
            factor = 1;
          }

          return Center(
            child: Container(
                constraints: BoxConstraints(
                  maxWidth: MediaQuery.of(context).size.width / factor,
                ),
                child: buildTimetable(fetchClassTimetable("/latest", null),
                    "aktueller Vertretungsplan")),
          );
        })
      ];
      return DefaultTabController(
        initialIndex: 0,
        length: 3,
        child: Scaffold(
          appBar: AppBar(
            title: const Text("GCG.MeinCantor"),
            centerTitle: true,
            bottom: const TabBar(
              indicatorColor: Palette.accent,
              enableFeedback: true,
              indicatorPadding: EdgeInsets.all(5),
              indicatorSize: TabBarIndicatorSize.label,
              tabs: <Widget>[
                Tab(
                  text: "Heute",
                  icon: Icon(Icons.calendar_today_outlined),
                ),
                Tab(
                  text: "Morgen",
                  icon: Icon(MdiIcons.calendarToday),
                ),
                Tab(
                  text: "Neuster Plan",
                  icon: Icon(Icons.calendar_view_day_outlined),
                ),
              ],
            ),
          ),
          drawer: Drawer(child: drawerElements),
          body: TabBarView(children: children),
        ),
      );
    } else {
      return const Center(child: Text("Derzeit nichts hier..."));
    }
  }
}