timetable performance optimization

2026-09-25 22:27:10 +02:00
parent ef7d17033d
commit ed8e52f475
13 changed files with 391 additions and 137 deletions
@@ -0,0 +1,45 @@
+import 'package:collection/collection.dart';
+
+import '../../../../../api/marianumconnect/queries/timetable_get_week/timetable_get_week_response.dart';
+import '../../../../../extensions/date_time.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;
+
+/// Returns the cache with [week] stored under [weekStart], pruned to the
+/// weeks near [viewedWeekStart] or [now]. Returns null when the stored week
+/// already has identical content, so callers can skip the emit entirely.
+Map<String, TimetableGetWeekResponse>? mergeWeekIntoCache(
+  Map<String, TimetableGetWeekResponse> cache,
+  DateTime weekStart,
+  TimetableGetWeekResponse week, {
+  required DateTime viewedWeekStart,
+  required DateTime now,
+}) {
+  final key = weekStart.weekKey();
+  final existing = cache[key];
+  if (existing != null &&
+      const DeepCollectionEquality().equals(existing.toJson(), week.toJson())) {
+    return null;
+  }
+
+  final viewedMonday = viewedWeekStart.mondayOfWeek;
+  final todayMonday = now.mondayOfWeek;
+  bool isNear(DateTime monday, DateTime anchor) =>
+      monday.difference(anchor).inDays.abs() <= kWeekCacheRadius * 7 + 1;
+
+  final updated = <String, TimetableGetWeekResponse>{};
+  for (final entry in cache.entries) {
+    final monday = DateTime.tryParse(entry.key);
+    if (monday == null ||
+        isNear(monday, viewedMonday) ||
+        isNear(monday, todayMonday)) {
+      updated[entry.key] = entry.value;
+    }
+  }
+  updated[key] = week;
+  return updated;
+}