Fix: Sync Log und verwaise Einträge

LehrerApp.Desktop/Services/UntisSyncService.cs

@@ -118,11 +118,20 @@ public class UntisSyncService : IDisposable
         var diffResult = _diffService.Diff(events, previousSnapshot, confirmedMappings, today,
             existingSupervisionDuties: _supervisionDuties.GetAll(), freeDates: BuildFreeDates(today));
 
+        var savedSubstitutionCount = 0;
         foreach (var candidate in diffResult.SubstitutionsToSave)
         {
             var existing = candidate.ExternalId is not null ? _substitutions.GetByExternalId(candidate.ExternalId) : null;
-            if (existing is not null) candidate.Id = existing.Id;
+            // Der Diff liefert auch weiterhin bestehende WebUntis-Abweichungen als Kandidaten.
+            // Ein unverändertes Upsert würde über Repository.OnChange bei jedem Poll erneut ein
+            // Sync-Ereignis erzeugen und bei vielen aktiven Abweichungen das Protokoll fluten.
+            if (existing is not null)
+            {
+                candidate.Id = existing.Id;
+                if (SubstitutionContentEquals(existing, candidate)) continue;
+            }
             _substitutions.Save(candidate);
+            savedSubstitutionCount++;
         }
         // Zuvor automatisch erzeugte Einträge, die jetzt nicht (mehr) gebraucht werden (siehe
         // UntisDiffResult.SubstitutionExternalIdsToDelete) - existiert keiner mit dieser
@@ -135,9 +144,17 @@ public class UntisSyncService : IDisposable
         foreach (var snapshot in diffResult.SnapshotToSave) _snapshots.Save(snapshot);
         foreach (var id in diffResult.SnapshotIdsToDelete) _snapshots.Delete(id);
 
-        return new UntisPollResult(events.Count, diffResult.SubstitutionsToSave.Count);
+        return new UntisPollResult(events.Count, savedSubstitutionCount);
     }
 
+    private static bool SubstitutionContentEquals(SubstitutionEntry left, SubstitutionEntry right) =>
+        left.Date == right.Date && left.Kind == right.Kind &&
+        left.PeriodNumber == right.PeriodNumber && left.AfterPeriod == right.AfterPeriod &&
+        left.FromPeriod == right.FromPeriod && left.ToPeriod == right.ToPeriod &&
+        left.IsAllDay == right.IsAllDay && left.GroupId == right.GroupId &&
+        left.GroupLabel == right.GroupLabel && left.Description == right.Description &&
+        left.Notes == right.Notes && left.ExternalId == right.ExternalId;
+
     // Ferien-/Feiertagstage im relevanten Zeitfenster (deutlich über das Lookahead-Fenster
     // hinaus, kostet bei kleinen Ferienlisten nichts) - verhindert, dass die aktive
     // "fehlt komplett im Feed"-Prüfung in UntisDiffService Ferientage fälschlich als Ausfall

LehrerApp.Desktop/ViewModels/ClassTeacher/ClassTeacherDetailsViewModel.cs

@@ -199,6 +199,7 @@ public partial class ClassTeacherDetailsViewModel : ObservableObject
     public bool ShowAbsenceListEmpty => !ShowMonthlyCalendar && !HasAbsenceEntries;
     public bool HasCategoryAggregates => CategoryAggregates.Count > 0;
     public bool HasOwnDocumentationEntries => OwnDocumentationEntries.Count > 0;
+    public bool CanAddOwnDocumentation => !Busy && _rosterMatches.Count > 0;
     /// Die Kategorien-Chipreihe fasst nur WebUntis-Kategorien zusammen (<see cref="CategoryAggregates"/>)
     /// — im Modus "Eigene Dokumentation" ausgeblendet, dort gibt es kein Äquivalent zu CategoryGroup.
     public bool ShowCategoryAggregates => HasCategoryAggregates && !ShowOwnDocumentation;
@@ -431,7 +432,7 @@ public partial class ClassTeacherDetailsViewModel : ObservableObject
             _loadedStart, _loadedEnd, StudentFilter);
         foreach (var d in entries)
         {
-            var name = _rosterMatches.First(m => m.StudentId == d.StudentId).DisplayName;
+            var name = DocumentationStudentDisplay(d, _rosterMatches);
             OwnDocumentationEntries.Add(new DocumentationItem(d, name));
         }
         OwnDocumentationCount = OwnDocumentationEntries.Count;
@@ -452,7 +453,9 @@ public partial class ClassTeacherDetailsViewModel : ObservableObject
     {
         var matchedIds = rosterMatches.Select(m => m.StudentId).ToHashSet();
         return all
-            .Where(d => !d.IsDeleted && matchedIds.Contains(d.StudentId) && d.Date >= start && d.Date <= end)
+            .Where(d => !d.IsDeleted &&
+                        (matchedIds.Contains(d.StudentId) || IsUnassignedClassDocumentation(d)) &&
+                        d.Date >= start && d.Date <= end)
             .Where(d => MatchesOwnDocStudentFilter(d, rosterMatches, studentFilter))
             .OrderByDescending(d => d.IsDraft).ThenByDescending(d => d.Date)
             .ToList();
@@ -462,14 +465,37 @@ public partial class ClassTeacherDetailsViewModel : ObservableObject
         IReadOnlyList<(Guid StudentId, string DisplayName)> rosterMatches, string studentFilter)
     {
         if (string.IsNullOrWhiteSpace(studentFilter)) return true;
+        if (IsUnassignedClassDocumentation(d))
+            return d.Participants.Any(p => NameContainsSearchTerm(p, studentFilter));
         var name = rosterMatches.FirstOrDefault(m => m.StudentId == d.StudentId).DisplayName;
-        return name is not null && UntisNameMatching.NamesMatch(name, studentFilter);
+        return name is not null && NameContainsSearchTerm(name, studentFilter);
+    }
+
+    private static bool IsUnassignedClassDocumentation(Documentation d) =>
+        d.StudentId == Guid.Empty && d.GroupId is null;
+
+    private static bool NameContainsSearchTerm(string name, string search)
+    {
+        if (UntisNameMatching.NamesMatch(name, search)) return true;
+        var searchKey = UntisNameMatching.NameKey(search);
+        return searchKey.Length > 0 && UntisNameMatching.NameKey(name).Split(' ').Contains(searchKey);
+    }
+
+    private static string DocumentationStudentDisplay(Documentation d,
+        IReadOnlyList<(Guid StudentId, string DisplayName)> rosterMatches)
+    {
+        if (d.StudentId != Guid.Empty)
+            return rosterMatches.FirstOrDefault(m => m.StudentId == d.StudentId).DisplayName
+                   ?? "Unbekannter Schülerbezug";
+        return d.Participants.Count > 0
+            ? $"Ohne festen Bezug · {string.Join(", ", d.Participants)}"
+            : "Ohne Schülerbezug";
     }
 
     [RelayCommand]
     private async Task AddOwnDocumentation()
     {
-        if (OnEditOwnDocumentation is null) return;
+        if (OnEditOwnDocumentation is null || !CanAddOwnDocumentation) return;
         var options = _rosterMatches.Select(m => new StudentOption(m.StudentId, m.DisplayName)).ToList();
         var result = await OnEditOwnDocumentation(options, null);
         if (result is null) return;
@@ -553,6 +579,7 @@ public partial class ClassTeacherDetailsViewModel : ObservableObject
         OnPropertyChanged(nameof(HasCategoryAggregates));
         OnPropertyChanged(nameof(ShowCategoryAggregates));
         OnPropertyChanged(nameof(HasOwnDocumentationEntries));
+        OnPropertyChanged(nameof(CanAddOwnDocumentation));
         OnPropertyChanged(nameof(UntisCriticalCount));
     }
 }

LehrerApp.Desktop/ViewModels/Settings/SettingsViewModel.Sync.cs

@@ -229,6 +229,13 @@ public partial class SettingsViewModel
         _eventQueue.MarkReviewed(item.Id);
         SyncConflicts.Remove(item);
     }
+
+    [RelayCommand]
+    private void ClearSyncConflicts()
+    {
+        _eventQueue.ClearConflicts();
+        SyncConflicts.Clear();
+    }
 }
 
 public class SyncConflictListItem(ConflictEntry c)

LehrerApp.Desktop/ViewModels/Students/DocumentationViewModels.cs

@@ -304,6 +304,11 @@ public partial class DocumentationDialogViewModel : ObservableObject
         var valid = true;
 
         if (CanPickStudent && SelectedStudent is null) { StudentError = "Bezug auswählen."; valid = false; }
+        if (!CanPickStudent && _studentId == Guid.Empty && _contextGroupId is null)
+        {
+            StudentError = "Die Schülerliste ist noch nicht geladen. Dialog schließen und erneut öffnen.";
+            valid = false;
+        }
 
         if (string.IsNullOrWhiteSpace(Title)) { TitleError = "Titel erforderlich."; valid = false; }
 

LehrerApp.Desktop/Views/ClassTeacher/ClassTeacherRegisterView.axaml

@@ -175,6 +175,7 @@
 
     <Grid Grid.Row="4" IsVisible="{Binding ShowOwnDocumentation}" RowDefinitions="Auto,*">
       <Button Grid.Row="0" Content="＋ Eintrag" Command="{Binding AddOwnDocumentationCommand}"
+              IsEnabled="{Binding CanAddOwnDocumentation}"
               HorizontalAlignment="Right" Margin="0,0,0,8"/>
       <ScrollViewer Grid.Row="1">
         <StackPanel>

LehrerApp.Desktop/Views/Settings/SettingsView.axaml

@@ -895,11 +895,15 @@
                          IsVisible="{Binding PairingStatus, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"/>
             </StackPanel>
 
-            <TextBlock Text="Konflikte" FontSize="14" FontWeight="SemiBold" Margin="0,10,0,0"
-                       IsVisible="{Binding SyncConflicts.Count}"/>
+            <Grid ColumnDefinitions="*,Auto" Margin="0,10,0,0" IsVisible="{Binding SyncConflicts.Count}">
+              <TextBlock Grid.Column="0" Text="Automatisch gelöste Konflikte" FontSize="14"
+                         FontWeight="SemiBold" VerticalAlignment="Center"/>
+              <Button Grid.Column="1" Content="Protokoll leeren" FontSize="11" Padding="8,3"
+                      Command="{Binding ClearSyncConflictsCommand}"/>
+            </Grid>
             <TextBlock FontSize="12" Opacity="0.6" TextWrapping="Wrap"
                        IsVisible="{Binding SyncConflicts.Count}"
-                       Text="Ein anderes Gerät hat dieselbe Änderung gleichzeitig gemacht — hier steht, welche Seite jeweils übernommen wurde."/>
+                       Text="Ein anderes Gerät hat dieselbe Änderung gleichzeitig gemacht. Der Konflikt ist bereits automatisch aufgelöst; hier steht nur das Ergebnis zur Kontrolle."/>
             <ItemsControl ItemsSource="{Binding SyncConflicts}">
               <ItemsControl.ItemTemplate>
                 <DataTemplate DataType="vm:SyncConflictListItem">