feat: add campus heilbronn events widget

assets/translations/de.json

@@ -244,5 +244,6 @@
   "visibility": "Sichtbarkeit",
   "utilizationAt": "Auslastung bei {}%",
   "showStudentCardPicture": "Student Card Bild zeigen",
-  "add_contact": "Zu Kontakten hinzufügen"
+  "add_contact": "Zu Kontakten hinzufügen",
+  "noUpcomingEvents": "Keine bevorstehenden Events"
 }

assets/translations/en.json

@@ -244,5 +244,6 @@
   "visibility": "Visibility",
   "utilizationAt": "Utilization at {}%",
   "showStudentCardPicture": "Show Student Card Picture",
-  "add_contact": "Add to contacts"
+  "add_contact": "Add to contacts",
+  "noUpcomingEvents": "No upcoming events"
 }

lib/base/util/grid_utility.dart

@@ -25,6 +25,10 @@ class GridUtility {
     }
   }
 
+  static int campusEventsCrossAxisCount(BuildContext context) {
+    return DeviceService.getType(context) == Device.phone ? 1 : 2;
+  }
+
   static int campusNumberOfItems(BuildContext context) {
     switch (DeviceService.getType(context)) {
       case Device.landscapeTablet:

lib/campusComponent/model/heilbronn_event.dart

@@ -0,0 +1,78 @@
+import 'package:intl/intl.dart';
+import 'package:xml/xml.dart';
+
+class HeilbronnEvent {
+  final String title;
+  final String link;
+  final String description;
+  final DateTime? publishedAt;
+  final DateTime? startDate;
+  final DateTime? endDate;
+  final String? time;
+  final String? location;
+
+  const HeilbronnEvent({
+    required this.title,
+    required this.link,
+    required this.description,
+    this.publishedAt,
+    this.startDate,
+    this.endDate,
+    this.time,
+    this.location,
+  });
+
+  DateTime? get eventDate => startDate ?? publishedAt;
+
+  static List<HeilbronnEvent> listFromRss(String rss) {
+    try {
+      final document = XmlDocument.parse(rss);
+      final events = document
+          .findAllElements('item')
+          .map((item) {
+            final description = _elementText(item, 'description');
+            final pubDate = _parsePubDate(_elementText(item, 'pubDate'));
+
+            return HeilbronnEvent(
+              title: _elementText(item, 'title'),
+              link: _elementText(item, 'link'),
+              description: description,
+              publishedAt: pubDate,
+              startDate: DateTime.tryParse(_elementText(item, 'startDate')),
+              endDate: DateTime.tryParse(_elementText(item, 'endDate')),
+              time: _nullableText(item, 'time'),
+              location: _nullableText(item, 'location'),
+            );
+          })
+          .where((event) => event.title.isNotEmpty)
+          .toList();
+
+      events.sort((a, b) {
+        final firstDate = a.eventDate ?? DateTime(0);
+        final secondDate = b.eventDate ?? DateTime(0);
+        return firstDate.compareTo(secondDate);
+      });
+      return events;
+    } catch (_) {
+      return [];
+    }
+  }
+
+  static String _elementText(XmlElement item, String name) {
+    final elements = item.findElements(name);
+    return elements.isEmpty ? '' : elements.first.innerText.trim();
+  }
+
+  static String? _nullableText(XmlElement item, String name) {
+    final text = _elementText(item, name);
+    return text.isEmpty ? null : text;
+  }
+
+  static DateTime? _parsePubDate(String value) {
+    try {
+      return DateFormat('EEE, dd MMM yyyy HH:mm:ss Z', 'en_US').parse(value);
+    } catch (_) {
+      return null;
+    }
+  }
+}

lib/campusComponent/screen/campus_screen.dart

@@ -1,4 +1,5 @@
 import 'package:campus_flutter/campusComponent/view/studentClub/student_club_widget_view.dart';
+import 'package:campus_flutter/campusComponent/view/heilbronnEvents/heilbronn_events_widget_view.dart';
 import 'package:campus_flutter/campusComponent/view/movie/movies_widget_view.dart';
 import 'package:campus_flutter/campusComponent/view/news/news_widget_view.dart';
 import 'package:flutter/material.dart';
@@ -32,6 +33,7 @@ class CampusScreen extends StatelessWidget {
         child: Column(
           children: [
             NewsWidgetView(),
+            HeilbronnEventsWidgetView(),
             StudentClubWidgetView(),
             MovieWidgetView(),
           ],

lib/campusComponent/service/heilbronn_event_service.dart

@@ -0,0 +1,15 @@
+import 'package:campus_flutter/campusComponent/model/heilbronn_event.dart';
+import 'package:dio/dio.dart';
+
+class HeilbronnEventService {
+  static String feedUrl(String languageCode) => languageCode == 'de'
+      ? 'https://hn.fs.tum.de/de/events/index.xml'
+      : 'https://hn.fs.tum.de/events/index.xml';
+
+  static final _dio = Dio();
+
+  static Future<List<HeilbronnEvent>> fetchEvents(String languageCode) async {
+    final response = await _dio.get<String>(feedUrl(languageCode));
+    return HeilbronnEvent.listFromRss(response.data ?? '');
+  }
+}

lib/campusComponent/view/heilbronnEvents/heilbronn_event_card_view.dart

@@ -0,0 +1,62 @@
+import 'package:campus_flutter/base/extensions/context.dart';
+import 'package:campus_flutter/base/util/string_parser.dart';
+import 'package:campus_flutter/base/util/url_launcher.dart';
+import 'package:campus_flutter/campusComponent/model/heilbronn_event.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+class HeilbronnEventCardView extends ConsumerWidget {
+  const HeilbronnEventCardView({super.key, required this.event});
+
+  final HeilbronnEvent event;
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    return InkWell(
+      borderRadius: BorderRadius.circular(12),
+      onTap: () => UrlLauncher.urlString(event.link, ref),
+      child: Card(
+        margin: EdgeInsets.zero,
+        clipBehavior: Clip.hardEdge,
+        child: Padding(
+          padding: EdgeInsets.all(context.halfPadding * 1.5),
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            crossAxisAlignment: CrossAxisAlignment.start,
+            children: [
+              Text(
+                event.title,
+                style: Theme.of(context).textTheme.titleMedium?.copyWith(
+                  fontWeight: FontWeight.w500,
+                ),
+                maxLines: 2,
+                overflow: TextOverflow.ellipsis,
+              ),
+              if (event.eventDate != null)
+                Text(
+                  StringParser.dateFormatter(event.eventDate!, context),
+                  style: Theme.of(context).textTheme.bodySmall,
+                  maxLines: 1,
+                  overflow: TextOverflow.ellipsis,
+                ),
+              if (event.time != null)
+                Text(
+                  event.time!,
+                  style: Theme.of(context).textTheme.bodySmall,
+                  maxLines: 1,
+                  overflow: TextOverflow.ellipsis,
+                ),
+              if (event.location != null)
+                Text(
+                  event.location!,
+                  style: Theme.of(context).textTheme.bodySmall,
+                  maxLines: 1,
+                  overflow: TextOverflow.ellipsis,
+                ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}

lib/campusComponent/view/heilbronnEvents/heilbronn_events_widget_view.dart

@@ -0,0 +1,120 @@
+import 'package:campus_flutter/base/enums/error_handling_view_type.dart';
+import 'package:campus_flutter/base/errorHandling/error_handling_router.dart';
+import 'package:campus_flutter/base/extensions/context.dart';
+import 'package:campus_flutter/base/util/delayed_loading_indicator.dart';
+import 'package:campus_flutter/base/util/grid_utility.dart';
+import 'package:campus_flutter/campusComponent/model/heilbronn_event.dart';
+import 'package:campus_flutter/campusComponent/view/heilbronnEvents/heilbronn_event_card_view.dart';
+import 'package:campus_flutter/campusComponent/viewmodel/heilbronn_events_viewmodel.dart';
+import 'package:campus_flutter/homeComponent/view/widget/widget_frame_view.dart';
+import 'package:easy_localization/easy_localization.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+class HeilbronnEventsWidgetView extends ConsumerStatefulWidget {
+  const HeilbronnEventsWidgetView({super.key});
+
+  @override
+  ConsumerState<ConsumerStatefulWidget> createState() =>
+      _HeilbronnEventsWidgetViewState();
+}
+
+class _HeilbronnEventsWidgetViewState
+    extends ConsumerState<HeilbronnEventsWidgetView> {
+  String? _languageCode;
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    final languageCode = context.locale.languageCode;
+    if (_languageCode == languageCode) return;
+    _languageCode = languageCode;
+    ref.read(heilbronnEventsViewModel).fetch(languageCode);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return StreamBuilder(
+      stream: ref.watch(heilbronnEventsViewModel).isNearHeilbronn,
+      builder: (context, nearbySnapshot) {
+        if (nearbySnapshot.data == false) {
+          return const SizedBox.shrink();
+        }
+
+        return StreamBuilder(
+          stream: ref.watch(heilbronnEventsViewModel).events,
+          builder: (context, eventsSnapshot) {
+            return WidgetFrameView(
+              titleWidget: Text(
+                'Campus Heilbronn Events',
+                style: Theme.of(context).textTheme.titleMedium,
+                maxLines: 1,
+                overflow: TextOverflow.ellipsis,
+              ),
+              child: _body(eventsSnapshot),
+            );
+          },
+        );
+      },
+    );
+  }
+
+  Widget _body(AsyncSnapshot<List<HeilbronnEvent>?> snapshot) {
+    if (snapshot.hasData) {
+      if (snapshot.data!.isEmpty) {
+        return AspectRatio(
+          aspectRatio: 2,
+          child: Card(
+            child: Center(
+              child: Text(
+                'noUpcomingEvents'.tr(),
+                style: Theme.of(context).textTheme.bodyMedium,
+              ),
+            ),
+          ),
+        );
+      }
+      final events = snapshot.data!
+          .take(GridUtility.campusNumberOfItems(context))
+          .toList();
+      final textScale = MediaQuery.textScalerOf(context).scale(1);
+      return Padding(
+        padding: EdgeInsets.symmetric(horizontal: context.padding),
+        child: GridView.builder(
+          shrinkWrap: true,
+          physics: const NeverScrollableScrollPhysics(),
+          padding: EdgeInsets.zero,
+          itemCount: events.length,
+          gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
+            crossAxisCount: GridUtility.campusEventsCrossAxisCount(context),
+            mainAxisSpacing: context.padding,
+            crossAxisSpacing: context.padding,
+            mainAxisExtent: 128 * textScale,
+          ),
+          itemBuilder: (context, index) =>
+              HeilbronnEventCardView(event: events[index]),
+        ),
+      );
+    } else if (snapshot.hasError) {
+      return AspectRatio(
+        aspectRatio: 2,
+        child: Card(
+          child: ErrorHandlingRouter(
+            error: snapshot.error,
+            errorHandlingViewType: ErrorHandlingViewType.textOnly,
+            retry: (() => ref
+                .read(heilbronnEventsViewModel)
+                .fetch(context.locale.languageCode)),
+          ),
+        ),
+      );
+    } else {
+      return const AspectRatio(
+        aspectRatio: 2,
+        child: Card(
+          child: DelayedLoadingIndicator(name: 'Campus Heilbronn Events'),
+        ),
+      );
+    }
+  }
+}

lib/campusComponent/viewmodel/heilbronn_events_viewmodel.dart

@@ -0,0 +1,64 @@
+import 'package:campus_flutter/base/services/location_service.dart';
+import 'package:campus_flutter/campusComponent/model/heilbronn_event.dart';
+import 'package:campus_flutter/campusComponent/service/heilbronn_event_service.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:geolocator/geolocator.dart';
+import 'package:rxdart/rxdart.dart';
+
+final heilbronnEventsViewModel = Provider(
+  (ref) => HeilbronnEventsViewModel(),
+);
+
+class HeilbronnEventsViewModel {
+  static const _heilbronnLatitude = 49.1472;
+  static const _heilbronnLongitude = 9.2165;
+  static const _heilbronnRadiusMeters = 100000.0;
+
+  final BehaviorSubject<List<HeilbronnEvent>?> events =
+      BehaviorSubject.seeded(null);
+  final BehaviorSubject<bool?> isNearHeilbronn = BehaviorSubject.seeded(null);
+
+  Future<void> fetch(String languageCode) async {
+    Position? position;
+    try {
+      position = await LocationService.determinePosition();
+    } catch (_) {
+      position = null;
+    }
+    if (position == null ||
+        !_isWithinRadius(position.latitude, position.longitude)) {
+      isNearHeilbronn.add(false);
+      events.add([]);
+      return;
+    }
+
+    isNearHeilbronn.add(true);
+    try {
+      final fetchedEvents = await HeilbronnEventService.fetchEvents(
+        languageCode,
+      );
+      fetchedEvents.removeWhere((event) {
+        final eventDate = event.eventDate;
+        return eventDate != null && eventDate.isBefore(_today());
+      });
+      events.add(fetchedEvents);
+    } catch (error) {
+      events.addError(error);
+    }
+  }
+
+  bool _isWithinRadius(double latitude, double longitude) {
+    return Geolocator.distanceBetween(
+          latitude,
+          longitude,
+          _heilbronnLatitude,
+          _heilbronnLongitude,
+        ) <=
+        _heilbronnRadiusMeters;
+  }
+
+  DateTime _today() {
+    final now = DateTime.now();
+    return DateTime(now.year, now.month, now.day);
+  }
+}