Add provider caching

uni/lib/model/providers/lazy/bus_stop_provider.dart

@@ -15,7 +15,7 @@ class BusStopProvider extends StateProviderNotifier {
   Map<String, BusStopData> _configuredBusStops = Map.identity();
   DateTime _timeStamp = DateTime.now();
 
-  BusStopProvider() : super(dependsOnSession: false);
+  BusStopProvider() : super(dependsOnSession: false, cacheDuration: null);
 
   UnmodifiableMapView<String, BusStopData> get configuredBusStops =>
       UnmodifiableMapView(_configuredBusStops);

uni/lib/model/providers/lazy/calendar_provider.dart

@@ -13,7 +13,8 @@ import 'package:uni/model/request_status.dart';
 class CalendarProvider extends StateProviderNotifier {
   List<CalendarEvent> _calendar = [];
 
-  CalendarProvider() : super(dependsOnSession: true);
+  CalendarProvider()
+      : super(dependsOnSession: true, cacheDuration: const Duration(days: 30));
 
   UnmodifiableListView<CalendarEvent> get calendar =>
       UnmodifiableListView(_calendar);

uni/lib/model/providers/lazy/exam_provider.dart

@@ -19,7 +19,8 @@ class ExamProvider extends StateProviderNotifier {
   List<String> _hiddenExams = [];
   Map<String, bool> _filteredExamsTypes = {};
 
-  ExamProvider() : super(dependsOnSession: true);
+  ExamProvider()
+      : super(dependsOnSession: true, cacheDuration: const Duration(days: 1));
 
   UnmodifiableListView<Exam> get exams => UnmodifiableListView(_exams);
 

uni/lib/model/providers/lazy/faculty_locations_provider.dart

@@ -10,7 +10,8 @@ import 'package:uni/model/request_status.dart';
 class FacultyLocationsProvider extends StateProviderNotifier {
   List<LocationGroup> _locations = [];
 
-  FacultyLocationsProvider() : super(dependsOnSession: false);
+  FacultyLocationsProvider()
+      : super(dependsOnSession: false, cacheDuration: const Duration(days: 30));
 
   UnmodifiableListView<LocationGroup> get locations =>
       UnmodifiableListView(_locations);

uni/lib/model/providers/lazy/home_page_provider.dart

@@ -8,7 +8,7 @@ class HomePageProvider extends StateProviderNotifier {
   List<FavoriteWidgetType> _favoriteCards = [];
   bool _isEditing = false;
 
-  HomePageProvider() : super(dependsOnSession: false);
+  HomePageProvider() : super(dependsOnSession: false, cacheDuration: null);
 
   List<FavoriteWidgetType> get favoriteCards => _favoriteCards.toList();
 

uni/lib/model/providers/lazy/lecture_provider.dart

@@ -17,7 +17,8 @@ import 'package:uni/model/request_status.dart';
 class LectureProvider extends StateProviderNotifier {
   List<Lecture> _lectures = [];
 
-  LectureProvider() : super(dependsOnSession: true);
+  LectureProvider()
+      : super(dependsOnSession: true, cacheDuration: const Duration(hours: 6));
 
   UnmodifiableListView<Lecture> get lectures => UnmodifiableListView(_lectures);
 

uni/lib/model/providers/lazy/library_occupation_provider.dart

@@ -12,7 +12,8 @@ import 'package:uni/model/request_status.dart';
 class LibraryOccupationProvider extends StateProviderNotifier {
   LibraryOccupation? _occupation;
 
-  LibraryOccupationProvider() : super(dependsOnSession: true);
+  LibraryOccupationProvider()
+      : super(dependsOnSession: true, cacheDuration: const Duration(hours: 1));
 
   LibraryOccupation? get occupation => _occupation;
 

uni/lib/model/providers/lazy/restaurant_provider.dart

@@ -13,7 +13,8 @@ import 'package:uni/model/request_status.dart';
 class RestaurantProvider extends StateProviderNotifier {
   List<Restaurant> _restaurants = [];
 
-  RestaurantProvider() : super(dependsOnSession: false);
+  RestaurantProvider()
+      : super(dependsOnSession: false, cacheDuration: const Duration(days: 1));
 
   UnmodifiableListView<Restaurant> get restaurants =>
       UnmodifiableListView(_restaurants);

uni/lib/model/providers/startup/profile_provider.dart

@@ -28,7 +28,8 @@ class ProfileProvider extends StateProviderNotifier {
   DateTime? _feesRefreshTime;
   DateTime? _printRefreshTime;
 
-  ProfileProvider() : super(dependsOnSession: true);
+  ProfileProvider()
+      : super(dependsOnSession: true, cacheDuration: const Duration(days: 1));
 
   String get feesRefreshTime => _feesRefreshTime.toString();
 

uni/lib/model/providers/startup/session_provider.dart

@@ -17,7 +17,11 @@ class SessionProvider extends StateProviderNotifier {
   Session _session = Session();
   List<String> _faculties = [];
 
-  SessionProvider() : super(dependsOnSession: false);
+  SessionProvider()
+      : super(
+            dependsOnSession: false,
+            cacheDuration: null,
+            initialStatus: RequestStatus.none);
 
   Session get session => _session;
 

uni/lib/model/providers/state_provider_notifier.dart

@@ -1,5 +1,6 @@
 import 'package:connectivity_plus/connectivity_plus.dart';
 import 'package:flutter/material.dart';
+import 'package:logger/logger.dart';
 import 'package:provider/provider.dart';
 import 'package:synchronized/synchronized.dart';
 import 'package:uni/controller/local_storage/app_shared_preferences.dart';
@@ -11,16 +12,21 @@ import 'package:uni/model/request_status.dart';
 
 abstract class StateProviderNotifier extends ChangeNotifier {
   static final Lock _lock = Lock();
-  RequestStatus _status = RequestStatus.busy;
+  RequestStatus _status;
   bool _initialized = false;
   DateTime? _lastUpdateTime;
   bool dependsOnSession;
+  Duration? cacheDuration;
 
   RequestStatus get status => _status;
 
   DateTime? get lastUpdateTime => _lastUpdateTime;
 
-  StateProviderNotifier({required this.dependsOnSession});
+  StateProviderNotifier(
+      {required this.dependsOnSession,
+      required this.cacheDuration,
+      RequestStatus? initialStatus})
+      : _status = initialStatus ?? RequestStatus.busy;
 
   Future<void> _loadFromStorage() async {
     _lastUpdateTime = await AppSharedPreferences.getLastDataClassUpdateTime(
@@ -30,20 +36,43 @@ abstract class StateProviderNotifier extends ChangeNotifier {
         await AppSharedPreferences.getPersistentUserInfo();
     final sessionIsPersistent =
         userPersistentInfo.item1 != '' && userPersistentInfo.item2 != '';
+
     if (sessionIsPersistent) {
       await loadFromStorage();
+      Logger().i("Loaded $runtimeType info from storage");
+    } else {
+      Logger().i(
+          "Session is not persistent; skipping $runtimeType load from storage");
     }
   }
 
-  Future<void> _loadFromRemote(Session session, Profile profile) async {
+  Future<void> _loadFromRemote(Session session, Profile profile,
+      {bool force = false}) async {
     final bool hasConnectivity =
         await Connectivity().checkConnectivity() != ConnectivityResult.none;
-    if (hasConnectivity) {
-      updateStatus(RequestStatus.busy);
-      await loadFromRemote(session, profile);
+    final shouldReload = force ||
+        _lastUpdateTime == null ||
+        cacheDuration == null ||
+        DateTime.now().difference(_lastUpdateTime!) > cacheDuration!;
+
+    if (shouldReload) {
+      if (hasConnectivity) {
+        updateStatus(RequestStatus.busy);
+        await loadFromRemote(session, profile);
+        if (_status == RequestStatus.successful) {
+          Logger().i("Loaded $runtimeType info from remote");
+        } else if (_status == RequestStatus.failed) {
+          Logger().e("Failed to load $runtimeType info from remote");
+        }
+      } else {
+        Logger().i("No internet connection; skipping $runtimeType remote load");
+      }
+    } else {
+      Logger().i(
+          "Last info for $runtimeType is within cache period ($cacheDuration); skipping remote load");
     }
 
-    if (!hasConnectivity || _status == RequestStatus.busy) {
+    if (!shouldReload || !hasConnectivity || _status == RequestStatus.busy) {
       // No online activity from provider
       updateStatus(RequestStatus.successful);
     } else {
@@ -65,7 +94,7 @@ abstract class StateProviderNotifier extends ChangeNotifier {
     final profile =
         Provider.of<ProfileProvider>(context, listen: false).profile;
 
-    _loadFromRemote(session, profile);
+    _loadFromRemote(session, profile, force: true);
   }
 
   Future<void> ensureInitialized(Session session, Profile profile) async {