improved performance and battery usage on older devices

lib/state/app/modules/timetable/bloc/timetable_bloc.dart

@@ -133,11 +133,7 @@ class TimetableBloc
 
   Future<void> _refreshSubjects() async {
     final subjects = await repo.data.getSubjects(renew: true);
-    add(
-      DataGathered(
-        (s) => s.copyWith(subjects: subjects, dataVersion: s.dataVersion + 1),
-      ),
-    );
+    add(DataGathered((s) => s.withReferenceData(subjects: subjects)));
   }
 
   Future<void> _loadCurrentWeek(
@@ -177,12 +173,11 @@ class TimetableBloc
 
       add(
         Emit(
-          (s) => s.copyWith(
+          (s) => s.withReferenceData(
             rooms: rooms,
             subjects: subjects,
             schoolHolidays: schoolHolidays,
             schoolyear: schoolyear,
-            dataVersion: s.dataVersion + 1,
           ),
         ),
       );
@@ -192,11 +187,7 @@ class TimetableBloc
 
     try {
       final timegrid = await repo.data.getTimegrid(renew: renew);
-      add(
-        Emit(
-          (s) => s.copyWith(timegrid: timegrid, dataVersion: s.dataVersion + 1),
-        ),
-      );
+      add(Emit((s) => s.withReferenceData(timegrid: timegrid)));
     } catch (_) {
       // Timegrid load failure falls back to a hardcoded schedule in the UI layer.
     }
@@ -212,12 +203,7 @@ class TimetableBloc
         renew: renew,
         onError: onError,
       );
-      add(
-        Emit(
-          (s) =>
-              s.copyWith(customEvents: events, dataVersion: s.dataVersion + 1),
-        ),
-      );
+      add(Emit((s) => s.withReferenceData(customEvents: events)));
     } catch (e) {
       onError?.call(e);
     }
@@ -225,11 +211,7 @@ class TimetableBloc
 
   Future<void> _refreshCustomEvents() async {
     final events = await repo.data.getCustomEvents(renew: true);
-    add(
-      DataGathered(
-        (s) => s.copyWith(customEvents: events, dataVersion: s.dataVersion + 1),
-      ),
-    );
+    add(DataGathered((s) => s.withReferenceData(customEvents: events)));
   }
 
   void _prefetchAdjacentWeeks(DateTime start, DateTime end) {

lib/state/app/modules/timetable/bloc/timetable_state.dart

@@ -7,6 +7,7 @@ import '../../../../../api/marianumconnect/queries/timetable_get_subjects/timeta
 import '../../../../../api/marianumconnect/queries/timetable_get_timegrid/timetable_get_timegrid_response.dart';
 import '../../../../../api/marianumconnect/queries/timetable_get_week/timetable_get_week_response.dart';
 import '../../../../../api/mhsl/custom_timetable_event/get/get_custom_timetable_event_response.dart';
+import '../../../../../utils/json_equality.dart';
 import 'week_cache.dart';
 
 part 'timetable_state.freezed.dart';
@@ -58,6 +59,45 @@ abstract class TimetableState with _$TimetableState {
     return copyWith(weekCache: updated, dataVersion: dataVersion + 1);
   }
 
+  /// Applies freshly loaded reference data. Values whose content equals the
+  /// current one keep the old instance, and when nothing changed at all this
+  /// returns `this` — every `dataVersion` bump and new identity makes the
+  /// calendar rebuild all appointments and break regions.
+  TimetableState withReferenceData({
+    TimetableGetRoomsResponse? rooms,
+    TimetableGetSubjectsResponse? subjects,
+    TimetableGetHolidaysResponse? schoolHolidays,
+    TimetableGetSchoolyearResponse? schoolyear,
+    TimetableGetTimegridResponse? timegrid,
+    GetCustomTimetableEventResponse? customEvents,
+  }) {
+    T? changed<T>(T? next, T? current) =>
+        next == null || sameJson(next, current) ? null : next;
+    final newRooms = changed(rooms, this.rooms);
+    final newSubjects = changed(subjects, this.subjects);
+    final newHolidays = changed(schoolHolidays, this.schoolHolidays);
+    final newSchoolyear = changed(schoolyear, this.schoolyear);
+    final newTimegrid = changed(timegrid, this.timegrid);
+    final newCustomEvents = changed(customEvents, this.customEvents);
+    if (newRooms == null &&
+        newSubjects == null &&
+        newHolidays == null &&
+        newSchoolyear == null &&
+        newTimegrid == null &&
+        newCustomEvents == null) {
+      return this;
+    }
+    return copyWith(
+      rooms: newRooms ?? this.rooms,
+      subjects: newSubjects ?? this.subjects,
+      schoolHolidays: newHolidays ?? this.schoolHolidays,
+      schoolyear: newSchoolyear ?? this.schoolyear,
+      timegrid: newTimegrid ?? this.timegrid,
+      customEvents: newCustomEvents ?? this.customEvents,
+      dataVersion: dataVersion + 1,
+    );
+  }
+
   bool get hasReferenceData =>
       rooms != null &&
       subjects != null &&

lib/state/app/modules/timetable/bloc/week_cache.dart

@@ -1,13 +1,12 @@
-import 'package:collection/collection.dart';
-
 import '../../../../../api/marianumconnect/queries/timetable_get_week/timetable_get_week_response.dart';
 import '../../../../../extensions/date_time.dart';
+import '../../../../../utils/json_equality.dart';
 
 /// Weeks kept around the viewed week and around today's week. Everything
 /// further away is dropped: every state emit re-serializes the whole cache for
 /// HydratedBloc and the calendar rebuilds its appointments from all of it, so
 /// an unbounded cache makes week swipes slower the longer the app is used.
-const int kWeekCacheRadius = 4;
+const int kWeekCacheRadius = 8;
 
 /// Returns the cache with [week] stored under [weekStart], pruned to the
 /// weeks near [viewedWeekStart] or [now]. Returns null when the stored week
@@ -21,10 +20,7 @@ Map<String, TimetableGetWeekResponse>? mergeWeekIntoCache(
 }) {
   final key = weekStart.weekKey();
   final existing = cache[key];
-  if (existing != null &&
-      const DeepCollectionEquality().equals(existing.toJson(), week.toJson())) {
-    return null;
-  }
+  if (sameJson(existing, week)) return null;
 
   final viewedMonday = viewedWeekStart.mondayOfWeek;
   final todayMonday = now.mondayOfWeek;