show classname instead of teacher name in teacher timetable view

lib/view/pages/timetable/data/lesson_labels.dart

@@ -0,0 +1,19 @@
+import '../../../../api/marianumconnect/queries/timetable_get_week/timetable_get_week_response.dart';
+
+final RegExp _whitespaceRun = RegExp(r'\s+');
+
+/// Collapses any line-break or whitespace run to a single space and trims.
+/// Returns null when input is null or fully whitespace. Webuntis sometimes
+/// returns multi-line values like "A30\n4" — this normalizes those so labels
+/// render on a single line.
+String? collapseWhitespace(String? s) {
+  if (s == null) return null;
+  final cleaned = s.replaceAll(_whitespaceRun, ' ').trim();
+  return cleaned.isEmpty ? null : cleaned;
+}
+
+/// "7a, 7b" — shared by the calendar tile factory and the home-widget mapper
+/// so both surfaces render identical class labels on teacher plans.
+extension LessonClassLabel on McTimetableEntry {
+  String? get classLabel => collapseWhitespace(classNames.join(', '));
+}

lib/view/pages/timetable/data/lesson_merger.dart

@@ -1,3 +1,5 @@
+import 'package:flutter/foundation.dart';
+
 import '../../../../api/marianumconnect/queries/timetable_get_week/timetable_get_week_response.dart';
 
 /// Combines back-to-back lessons with identical subject/room/teacher/status
@@ -44,6 +46,9 @@ class LessonMerger {
         b.teachers.firstOrNull?.shortName) {
       return false;
     }
+    // Relevant für Lehrerpläne: gleicher Lehrer/Fach/Raum, aber verschiedene
+    // Klassen dürfen nicht zu einem Block verschmelzen.
+    if (!listEquals(a.classNames, b.classNames)) return false;
     if (a.status != b.status) return false;
     // Lower bound on the gap — without it, two identical-metadata lessons that
     // overlap in time would silently collapse into one.

lib/view/pages/timetable/data/timetable_appointment_factory.dart

@@ -8,6 +8,7 @@ import '../../../../api/mhsl/custom_timetable_event/custom_timetable_event.dart'
 import '../../../../storage/timetable_settings.dart';
 import 'arbitrary_appointment.dart';
 import 'lesson_color.dart';
+import 'lesson_labels.dart';
 import 'lesson_merger.dart';
 import 'lesson_status.dart';
 import 'lesson_type_label.dart';
@@ -23,6 +24,10 @@ class TimetableAppointmentFactory {
   final TimetableSettings settings;
   final DateTime now;
 
+  /// Teacher plans (a teacher's own plan or a foreign teacher view) show the
+  /// class on the tile instead of the teacher's own name.
+  final bool showClassInsteadOfTeacher;
+
   TimetableAppointmentFactory({
     required this.lessons,
     required this.customEvents,
@@ -30,6 +35,7 @@ class TimetableAppointmentFactory {
     required this.settings,
     required this.now,
     this.holidays = const [],
+    this.showClassInsteadOfTeacher = false,
   });
 
   List<Appointment> build() {
@@ -130,7 +136,7 @@ class TimetableAppointmentFactory {
       location: event.description.trim().isEmpty
           ? null
           : event.description.trim(),
-      subject: _collapseWhitespace(event.title) ?? event.title,
+      subject: collapseWhitespace(event.title) ?? event.title,
       recurrenceRule: parsed.rule,
       recurrenceExceptionDates: exceptionDates.isEmpty ? null : exceptionDates,
       color:
@@ -222,7 +228,7 @@ class TimetableAppointmentFactory {
         TimetableNameMode.longName => lookup?.longName ?? subjectShort,
         TimetableNameMode.alternateName => lookup?.longName ?? subjectShort,
       };
-      final collapsed = _collapseWhitespace(name);
+      final collapsed = collapseWhitespace(name);
       if (collapsed != null) return collapsed;
     }
     // Subject leer → Titel aus dem Lesson-Type ableiten. Pausenaufsicht etc.
@@ -233,10 +239,13 @@ class TimetableAppointmentFactory {
 
   String _locationLabel(McTimetableEntry lesson) {
     final roomName =
-        _collapseWhitespace(lesson.rooms.firstOrNull) ?? 'Unbekannt';
-    final teacherName =
-        _teacherLabel(lesson.teachers.firstOrNull) ?? 'Unbekannt';
-    return '$roomName\n$teacherName';
+        collapseWhitespace(lesson.rooms.firstOrNull) ?? 'Unbekannt';
+    // Klassenlose Einträge (Aufsichten etc.) fallen auf den Lehrer zurück.
+    final secondLine =
+        (showClassInsteadOfTeacher ? lesson.classLabel : null) ??
+        _teacherLabel(lesson.teachers.firstOrNull) ??
+        'Unbekannt';
+    return '$roomName\n$secondLine';
   }
 
   /// Backend serves teachers with their full display name ("Stefan Müller"),
@@ -245,27 +254,11 @@ class TimetableAppointmentFactory {
   /// overview; the detail sheet still renders the full name as a subtitle.
   static String? _teacherLabel(McTimetableTeacher? teacher) {
     if (teacher == null) return null;
-    final display = _collapseWhitespace(teacher.displayName);
+    final display = collapseWhitespace(teacher.displayName);
     if (display != null && display.isNotEmpty) {
       final parts = display.split(' ');
       return parts.isEmpty ? display : parts.last;
     }
-    return _collapseWhitespace(teacher.shortName);
-  }
-
-  /// Collapses any line-break or whitespace run to a single space and trims.
-  /// Returns null when input is null or fully whitespace. Webuntis sometimes
-  /// returns multi-line room names like "A30\n4" — this normalizes those so
-  /// the tile renders the room on a single line.
-  static String? _collapseWhitespace(String? s) {
-    if (s == null) return null;
-    final cleaned = s
-        .replaceAll('\r\n', ' ')
-        .replaceAll('\n', ' ')
-        .replaceAll('\r', ' ')
-        .replaceAll('\t', ' ')
-        .replaceAll(RegExp(r'\s+'), ' ')
-        .trim();
-    return cleaned.isEmpty ? null : cleaned;
+    return collapseWhitespace(teacher.shortName);
   }
 }