feat: Fehlzeiten Calender

2026-09-15 10:02:33 +02:00
parent 70dc78904c
commit 1671796844
16 changed files with 477 additions and 16 deletions
@@ -229,6 +229,7 @@ public static class AppBootstrapper
        services.AddSingleton<LessonPlanTools>();
        services.AddSingleton<GroupMembershipTools>();
        services.AddSingleton<LetterTemplateTools>();
+        services.AddSingleton<StudentAttendanceCalendarService>();
        services.AddSingleton<CompetencyTools>();
        services.AddSingleton<GroupTools>();
        services.AddSingleton<UntisComparisonTools>();
@@ -19,7 +19,8 @@ public static class LetterDialogs
            App.Services.GetRequiredService<TemplateStore>(),
            App.Services.GetRequiredService<ITemplateRenderer>(),
            App.Services.GetRequiredService<IGroupMembershipRepository>(),
-            App.Services.GetRequiredService<IGroupRepository>());
+            App.Services.GetRequiredService<IGroupRepository>(),
+            options => App.Services.GetRequiredService<StudentAttendanceCalendarService>().Build(student, options));
        var dialog = new CreateLetterDialog { DataContext = vm };
        var path = await dialog.ShowDialog<string?>(owner);
        if (!string.IsNullOrEmpty(path) && File.Exists(path))
@@ -15,7 +15,7 @@ public static class LetterPlaceholderBuilder
 {
    public static Dictionary<string, PlaceholderValue> BuildStandardValues(
        Student student, Contact? contact, LearningGroup? group, DateOnly date,
-        string letterText, string teacherName)
+        string letterText, string teacherName, DrawingValue? attendanceCalendar = null)
    {
        var cityLine = string.Join(" ", new[] { contact?.PostalCode, contact?.City }.Where(x => !string.IsNullOrWhiteSpace(x)));
        var address = string.Join(Environment.NewLine, new[] { contact?.Name, contact?.Street, cityLine }.Where(x => !string.IsNullOrWhiteSpace(x)));
@@ -29,6 +29,7 @@ public static class LetterPlaceholderBuilder
            ["Contact.Street"] = new TextValue(contact?.Street ?? ""), ["Contact.PostalCode"] = new TextValue(contact?.PostalCode ?? ""),
            ["Contact.City"] = new TextValue(contact?.City ?? ""), ["Letter.Salutation"] = new TextValue(contact?.LetterSalutation ?? ""),
            ["Group.Name"] = new TextValue(group?.Name ?? ""), ["SchoolYear"] = new TextValue(group?.SchoolYear ?? ""),
+            [StudentAttendanceCalendarDrawingBuilder.PlaceholderName] = attendanceCalendar ?? new DrawingValue([], 0),
        };
    }

@@ -36,6 +37,7 @@ public static class LetterPlaceholderBuilder
    {
        TextValue x => string.IsNullOrWhiteSpace(x.Value),
        MultilineValue x => string.IsNullOrWhiteSpace(x.Value),
+        DrawingValue x => x.ContentHeight <= 0 || x.Commands.Count == 0,
        _ => false,
    };
 }
@@ -19,7 +19,8 @@ namespace LehrerApp.Desktop.Services.Mcp.Tools;
 /// tatsächlich nützlichen Fall ab: eine bestehende, vom Nutzer gestaltete Vorlage mit Werten füllen.</summary>
 public class LetterTemplateTools(
    TemplateStore templates, ITemplateLoader loader, ITemplateRenderer renderer,
-    IStudentRepository students, IGroupRepository groups)
+    IStudentRepository students, IGroupRepository groups,
+    StudentAttendanceCalendarService? attendanceCalendars = null)
 {
    [Description("Listet importierte Elternbrief-Vorlagen mit ihren deklarierten Platzhaltern (Name, Typ, Pflichtfeld, konstant).")]
    public List<LetterTemplateDto> ListLetterTemplates()
@@ -73,7 +74,8 @@ public class LetterTemplateTools(
        var group = groupId is { } gid ? groups.GetById(gid) : null;
        var date = letterDate ?? DateOnly.FromDateTime(DateTime.Today);

-        var values = LetterPlaceholderBuilder.BuildStandardValues(student, contact, group, date, letterText, teacherName);
+        var values = LetterPlaceholderBuilder.BuildStandardValues(student, contact, group, date, letterText,
+            teacherName, attendanceCalendars?.Build(student, date));
        foreach (var (name, raw) in extraValues ?? [])
        {
            var definition = loaded.Manifest.Placeholders.FirstOrDefault(p => p.Name == name);
@@ -0,0 +1,129 @@
+using System.Globalization;
+using LehrerApp.Core.Interfaces;
+using LehrerApp.Core.Models;
+using LehrerApp.Desktop.ViewModels.ClassTeacher;
+using LehrerApp.Templating;
+
+namespace LehrerApp.Desktop.Services;
+
+public enum AttendanceCalendarSize { Small, Medium, Large }
+
+public sealed record AttendanceCalendarOptions(DateOnly StartMonth, int MonthCount,
+    AttendanceCalendarSize Size = AttendanceCalendarSize.Medium)
+{
+    public DateOnly NormalizedStartMonth => new(StartMonth.Year, StartMonth.Month, 1);
+    public int NormalizedMonthCount => Math.Clamp(MonthCount, 1, 3);
+}
+
+/// <summary>Erzeugt den portablen Advanced-Content-Platzhalter für Elternbriefe aus derselben
+/// priorisierten Monatsansicht, die im Klassenlehrer-Sidebar-Widget verwendet wird.</summary>
+public static class StudentAttendanceCalendarDrawingBuilder
+{
+    public const string PlaceholderName = "Student.AttendanceCalendar";
+
+    public static DrawingValue Build(string studentName, DateOnly month,
+        IReadOnlyList<ClassAbsenceDaySummaryRow> absences,
+        IReadOnlyList<UntisForeignClassRegisterEventDto> registerEntries) =>
+        Build(studentName, new AttendanceCalendarOptions(month, 1), absences, registerEntries);
+
+    public static DrawingValue Build(string studentName, AttendanceCalendarOptions options,
+        IReadOnlyList<ClassAbsenceDaySummaryRow> absences,
+        IReadOnlyList<UntisForeignClassRegisterEventDto> registerEntries)
+    {
+        const float width = 170;
+        var scale = options.Size switch
+        {
+            AttendanceCalendarSize.Small => .7f,
+            AttendanceCalendarSize.Large => 1f,
+            _ => .85f,
+        };
+        var contentWidth = width * scale;
+        var cellWidth = contentWidth / 7;
+        var cellHeight = 10 * scale;
+        var monthGap = 6 * scale;
+        var first = options.NormalizedStartMonth;
+        var monthCount = options.NormalizedMonthCount;
+        var commands = new List<DrawingCommand>
+        {
+            new DrawStringEx(0, 0, 7 * scale, contentWidth, "Anwesenheit",
+                DrawingTextAlignment.AlignLeft, 11 * scale, Color: "#1F2937", Bold: true),
+            new DrawStringEx(0, 7 * scale, 6 * scale, contentWidth, studentName,
+                DrawingTextAlignment.AlignLeft, 8 * scale, Color: "#6B7280"),
+        };
+        var weekdays = new[] { "Mo", "Di", "Mi", "Do", "Fr", "Sa", "So" };
+        var y = 15 * scale;
+        for (var monthIndex = 0; monthIndex < monthCount; monthIndex++)
+        {
+            var current = first.AddMonths(monthIndex);
+            var days = ClassTeacherOverviewViewModel.BuildCompactMonthDays(current, absences, registerEntries,
+                DateOnly.FromDateTime(DateTime.Today), studentName);
+            var offset = ((int)current.DayOfWeek + 6) % 7;
+            var weeks = (int)Math.Ceiling((offset + days.Count) / 7d);
+            commands.Add(new DrawStringEx(0, y, 7 * scale, contentWidth,
+                current.ToString("MMMM yyyy", CultureInfo.GetCultureInfo("de-DE")),
+                DrawingTextAlignment.AlignLeft, 9 * scale, Color: "#374151", Bold: true));
+            y += 7 * scale;
+            for (var column = 0; column < 7; column++)
+                commands.Add(new DrawStringEx(column * cellWidth, y, 6 * scale, cellWidth, weekdays[column],
+                    DrawingTextAlignment.AlignCenter, 7 * scale, Color: "#6B7280", Bold: true));
+            y += 7 * scale;
+
+            foreach (var day in days)
+            {
+                var index = offset + day.Date.Day - 1;
+                var column = index % 7;
+                var row = index / 7;
+                var x = column * cellWidth;
+                var cellY = y + row * cellHeight;
+                commands.Add(new DrawRectangle(x + scale, cellY, cellWidth - 2 * scale, cellHeight - scale,
+                    "#D1D5DB", .35f, day.HasSignal ? day.SignalColorHex : "#FFFFFF"));
+                commands.Add(new DrawStringEx(x, cellY + scale, cellHeight - 2 * scale, cellWidth,
+                    day.HasSignal ? day.SignalCode : day.DayNumber, DrawingTextAlignment.AlignCenter, 7 * scale,
+                    Color: day.HasSignal ? "#FFFFFF" : "#374151", Bold: day.HasSignal));
+            }
+            y += weeks * cellHeight + monthGap;
+        }
+
+        commands.Add(new DrawStringEx(0, y, 8 * scale, contentWidth,
+            "U unentschuldigt · A abwesend · V verspätet · E entschuldigt · ! Klassenbuch",
+            DrawingTextAlignment.AlignLeft, 6.5f * scale, Color: "#6B7280"));
+        return new DrawingValue(commands, y + 9 * scale);
+    }
+}
+
+/// <summary>Liest ausschließlich den lokalen WebUntis-Cache. Das Öffnen oder Rendern eines
+/// Elternbriefs löst dadurch keinen unerwarteten Netzwerkabruf aus.</summary>
+public sealed class StudentAttendanceCalendarService(
+    WebUntisSettingsService settings,
+    IUntisAbsenceCacheRepository absenceCache,
+    IUntisClassRegisterCacheRepository registerCache,
+    IUntisStudentRosterCacheRepository rosterCache)
+{
+    public DrawingValue Build(Student student, DateOnly month) =>
+        Build(student, new AttendanceCalendarOptions(month, 1));
+
+    public DrawingValue Build(Student student, AttendanceCalendarOptions options)
+    {
+        var className = settings.HomeroomClassName;
+        if (string.IsNullOrWhiteSpace(className)) return new DrawingValue([], 0);
+
+        var first = options.NormalizedStartMonth;
+        var last = first.AddMonths(options.NormalizedMonthCount).AddDays(-1);
+        var rosterName = rosterCache.GetByClass(className)
+            .FirstOrDefault(r => UntisNameMatching.NamesMatch(r.DisplayName, student.FullName))?.DisplayName
+            ?? student.FullName;
+        var start = first.Year * 10000 + first.Month * 100 + first.Day;
+        var end = last.Year * 10000 + last.Month * 100 + last.Day;
+        var absences = absenceCache.GetByClassAndRange(className, start, end)
+            .Select(e => new UntisClassAbsenceEntryDto(e.StudentName, e.ExternKey, e.ClassName, e.Date,
+                e.AbsentPeriods, e.AbsentMinutes, e.TeacherUsernames, e.Subject, e.AbsenceReason, e.Note,
+                e.EntryId, e.HandledOn, e.Counts, e.ExcuseNote, e.PeriodNumber, e.Status, e.CountsAsFullDay))
+            .ToList();
+        var register = registerCache.GetByClassAndRange(className, start, end)
+            .Select(e => new UntisForeignClassRegisterEventDto(e.ClassName, e.Date, e.Subject, e.StudentName,
+                e.TeacherUsername, e.CategoryName, e.CategoryGroup, e.Text))
+            .ToList();
+        return StudentAttendanceCalendarDrawingBuilder.Build(rosterName, options,
+            ClassAbsenceDaySummaryRow.GroupByStudentAndDay(absences), register);
+    }
+}
@@ -18,6 +18,10 @@ public enum ClassTeacherStatusKind { Ok, Info, Warning, Danger }
 /// Schlagwort gezielt dämpfen kann, siehe <see cref="ClassTeacherRosterRow.MatchDomains"/>.</summary>
 public enum VorgangScoreDomain { Attendance, Lateness, Classbook }

+/// <summary>Auswahlbereich des kompakten Monatskalenders. Ein leerer Schülername steht für die
+/// bisherige Klassen-Gesamtansicht.</summary>
+public sealed record ClassTeacherCalendarScope(string? StudentName, string DisplayName);
+
 public sealed record ClassTeacherRosterRow(string StudentName, int? ExternKey, bool HasAbsenceToday,
    string? AbsenceTooltip, bool HasRecentClassRegisterEntry)
 {
@@ -424,6 +428,7 @@ public partial class ClassTeacherOverviewViewModel : ObservableObject
    public ObservableCollection<ClassTeacherPatternNotice> PatternNotices { get; } = [];
    public ObservableCollection<ClassTeacherOpenExcuseRow> OpenExcuses { get; } = [];
    public ObservableCollection<ClassTeacherCompactCalendarDay> CompactMonthDays { get; } = [];
+    public ObservableCollection<ClassTeacherCalendarScope> CalendarScopes { get; } = [];

    [ObservableProperty] private string? _homeroomClassName;
    [ObservableProperty] private int _activeTabIndex;
@@ -453,6 +458,7 @@ public partial class ClassTeacherOverviewViewModel : ObservableObject
    /// den "Klassenbuch öffnen"-Button gehängt statt in einer eigenen Kennzahlkarte.
    [ObservableProperty] private int _ownDocumentationFollowUpCount;
    [ObservableProperty] private int _ownDocumentationCriticalCount;
+    [ObservableProperty] private ClassTeacherCalendarScope? _selectedCalendarScope;

    // Zuletzt per Load() geholte WebUntis-Rohdaten, für RefreshFromLocalDataOnly() - damit ein
    // eingehendes Sync-Ereignis die Ansicht neu aufbauen kann, ohne selbst WebUntis anzufragen.
@@ -501,8 +507,17 @@ public partial class ClassTeacherOverviewViewModel : ObservableObject
    public double UnexcusedAbsenceFraction => StudentCount == 0 ? 0 : (double)UnexcusedAbsenceCount / StudentCount;
    public string DayOverviewTooltip => $"{PresentCount} anwesend · {LateCount} verspätet · " +
        $"{ExcusedAbsenceCount} entschuldigt · {UnexcusedAbsenceCount} unentschuldigt";
-    public string CompactMonthLabel => DateOnly.FromDateTime(DateTime.Today).ToString("MMMM yyyy",
-        System.Globalization.CultureInfo.GetCultureInfo("de-DE"));
+    public string CompactMonthLabel
+    {
+        get
+        {
+            var month = DateOnly.FromDateTime(DateTime.Today).ToString("MMMM yyyy",
+                System.Globalization.CultureInfo.GetCultureInfo("de-DE"));
+            return SelectedCalendarScope?.StudentName is { Length: > 0 }
+                ? $"{month} · {SelectedCalendarScope.DisplayName}"
+                : $"{month} · gesamte Klasse";
+        }
+    }

    public Func<Task>? OnNavigateToSettings { get; set; }
    public Func<Task>? OnNavigateToWorkload { get; set; }
@@ -534,6 +549,11 @@ public partial class ClassTeacherOverviewViewModel : ObservableObject
    partial void OnOpenExcuseOverflowCountChanged(int value) => OnPropertyChanged(nameof(HasOpenExcuseOverflow));
    partial void OnOwnDocumentationFollowUpCountChanged(int value) => OnPropertyChanged(nameof(HasOwnDocumentationAlerts));
    partial void OnOwnDocumentationCriticalCountChanged(int value) => OnPropertyChanged(nameof(HasOwnDocumentationAlerts));
+    partial void OnSelectedCalendarScopeChanged(ClassTeacherCalendarScope? value)
+    {
+        OnPropertyChanged(nameof(CompactMonthLabel));
+        if (CalendarScopes.Count > 0) RebuildCompactMonthFromCachedData();
+    }
    partial void OnSearchTextChanged(string value) => ApplyRosterFilter();
    partial void OnSelectedRosterFilterChanged(int value)
    {
@@ -548,7 +568,8 @@ public partial class ClassTeacherOverviewViewModel : ObservableObject
    {
        ActiveTabIndex = 0;
        Roster.Clear(); PrimaryRoster.Clear(); SecondaryRoster.Clear(); TrendDays.Clear(); PatternNotices.Clear();
-        OpenExcuses.Clear(); CompactMonthDays.Clear(); OpenExcuseOverflowCount = 0;
+        OpenExcuses.Clear(); CompactMonthDays.Clear(); CalendarScopes.Clear(); SelectedCalendarScope = null;
+        OpenExcuseOverflowCount = 0;
    }

    // Wird beim Navigieren auf diese Seite aufgerufen statt LoadCommand: baut nur den lokalen
@@ -678,6 +699,12 @@ public partial class ClassTeacherOverviewViewModel : ObservableObject
                     holidayWeekdaysExcluded, termStart, classRegisterEvents,
                     _patternScoreSettings.Load(), closedVorgaengeByNameKey)) Roster.Add(row);

+        CalendarScopes.Add(new ClassTeacherCalendarScope(null, "Gesamte Klasse"));
+        foreach (var student in students.OrderBy(s => s.DisplayName))
+            CalendarScopes.Add(new ClassTeacherCalendarScope(student.DisplayName,
+                ClassTeacherOverviewViewModel.DisplayStudentName(student.DisplayName)));
+        SelectedCalendarScope = CalendarScopes[0];
+
        StudentCount = Roster.Count;
        TodayAlertCount = Roster.Count(r => r.HasAbsenceToday);
        TodayUnexcusedCount = Roster.Count(r => r.IsUnexcused);
@@ -724,7 +751,7 @@ public partial class ClassTeacherOverviewViewModel : ObservableObject
    private void OpenMonthlyCalendar()
    {
        var today = DateOnly.FromDateTime(DateTime.Today);
-        DetailsTab.StudentFilter = "";
+        DetailsTab.StudentFilter = SelectedCalendarScope?.StudentName ?? "";
        DetailsTab.CalendarMonth = new DateOnly(today.Year, today.Month, 1);
        ActiveTabIndex = 2;
        DetailsTab.ShowCalendarCommand.Execute(null);
@@ -735,15 +762,29 @@ public partial class ClassTeacherOverviewViewModel : ObservableObject
    {
        CompactMonthDays.Clear();
        foreach (var day in BuildCompactMonthDays(new DateOnly(today.Year, today.Month, 1),
-                     absences, registerEntries, today))
+                     absences, registerEntries, today, SelectedCalendarScope?.StudentName))
            CompactMonthDays.Add(day);
    }

+    private void RebuildCompactMonthFromCachedData()
+    {
+        if (_lastAbsences is null || _lastClassRegisterEvents is null) return;
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        BuildCompactMonth(ClassAbsenceDaySummaryRow.GroupByStudentAndDay(_lastAbsences),
+            _lastClassRegisterEvents, today);
+    }
+
    public static IReadOnlyList<ClassTeacherCompactCalendarDay> BuildCompactMonthDays(DateOnly month,
        IReadOnlyList<ClassAbsenceDaySummaryRow> absences,
-        IReadOnlyList<UntisForeignClassRegisterEventDto> registerEntries, DateOnly today)
+        IReadOnlyList<UntisForeignClassRegisterEventDto> registerEntries, DateOnly today,
+        string? studentName = null)
    {
        var first = new DateOnly(month.Year, month.Month, 1);
+        if (!string.IsNullOrWhiteSpace(studentName))
+        {
+            absences = absences.Where(a => UntisNameMatching.NamesMatch(a.StudentName, studentName)).ToList();
+            registerEntries = registerEntries.Where(e => UntisNameMatching.NamesMatch(e.StudentName, studentName)).ToList();
+        }
        var registerRows = registerEntries
            .Select(e => (Entry: e, Valid: TryDate(e.Date, out var date), Date: date))
            .Where(x => x.Valid && x.Date.Year == first.Year && x.Date.Month == first.Month)
@@ -768,6 +809,12 @@ public partial class ClassTeacherOverviewViewModel : ObservableObject
        return result;
    }

+    internal static string DisplayStudentName(string value)
+    {
+        var parts = value.Split(' ', StringSplitOptions.RemoveEmptyEntries);
+        return parts.Length < 2 ? value : string.Join(" ", parts.Skip(1).Append(parts[0]));
+    }
+
    private static int SignalPriority(ClassTeacherCalendarEventKind kind) => kind switch
    {
        ClassTeacherCalendarEventKind.Unexcused => 0,
@@ -0,0 +1,35 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using LehrerApp.Desktop.Services;
+
+namespace LehrerApp.Desktop.ViewModels.Students;
+
+public sealed record AttendanceCalendarSizeChoice(AttendanceCalendarSize Value, string DisplayName);
+
+public partial class AttendanceCalendarConfigurationViewModel : ObservableObject
+{
+    [ObservableProperty] private DateTimeOffset? _startMonth;
+    [ObservableProperty] private int _monthCount;
+    [ObservableProperty] private AttendanceCalendarSizeChoice _selectedSize;
+
+    public IReadOnlyList<int> MonthCounts { get; } = [1, 2, 3];
+    public IReadOnlyList<AttendanceCalendarSizeChoice> Sizes { get; } =
+    [
+        new(AttendanceCalendarSize.Small, "Klein"),
+        new(AttendanceCalendarSize.Medium, "Standard"),
+        new(AttendanceCalendarSize.Large, "Groß"),
+    ];
+
+    public AttendanceCalendarConfigurationViewModel(AttendanceCalendarOptions options)
+    {
+        StartMonth = new DateTimeOffset(options.NormalizedStartMonth.ToDateTime(TimeOnly.MinValue));
+        MonthCount = options.NormalizedMonthCount;
+        SelectedSize = Sizes.First(s => s.Value == options.Size);
+    }
+
+    public AttendanceCalendarOptions BuildResult()
+    {
+        var date = DateOnly.FromDateTime((StartMonth ?? DateTimeOffset.Now).LocalDateTime);
+        return new AttendanceCalendarOptions(new DateOnly(date.Year, date.Month, 1), MonthCount,
+            SelectedSize.Value);
+    }
+}
@@ -12,6 +12,9 @@ public partial class CreateLetterDialogViewModel : ObservableObject
    private readonly Student _student;
    private readonly TemplateStore _templates;
    private readonly ITemplateRenderer _renderer;
+    private readonly Func<AttendanceCalendarOptions, DrawingValue>? _attendanceCalendarFactory;
+    private AttendanceCalendarOptions _attendanceCalendarOptions = new(
+        new DateOnly(DateTime.Today.Year, DateTime.Today.Month, 1), 1);

    [ObservableProperty] private LetterTemplateChoice? _selectedTemplate;
    [ObservableProperty] private LetterContactChoice? _selectedContact;
@@ -21,6 +24,9 @@ public partial class CreateLetterDialogViewModel : ObservableObject
    [ObservableProperty] private string _teacherName = "";
    [ObservableProperty] private string _generationError = "";
    [ObservableProperty] private bool _canGenerate;
+    [ObservableProperty] private bool _usesAttendanceCalendar;
+    [ObservableProperty] private bool _attendanceCalendarConfigured;
+    [ObservableProperty] private string _attendanceCalendarSummary = "1 Monat · Standardgröße";

    public string StudentName => _student.FullName;
    public ObservableCollection<LetterTemplateChoice> Templates { get; } = [];
@@ -34,9 +40,11 @@ public partial class CreateLetterDialogViewModel : ObservableObject
        $"{SelectedTemplate?.Name ?? "Elternbrief"}_{_student.LastName}_{_student.FirstName}.pdf");

    public CreateLetterDialogViewModel(Student student, TemplateStore templates, ITemplateRenderer renderer,
-        IGroupMembershipRepository memberships, IGroupRepository groups)
+        IGroupMembershipRepository memberships, IGroupRepository groups,
+        Func<AttendanceCalendarOptions, DrawingValue>? attendanceCalendarFactory = null)
    {
        _student = student; _templates = templates; _renderer = renderer;
+        _attendanceCalendarFactory = attendanceCalendarFactory;
        foreach (var template in templates.GetTemplates()) Templates.Add(new(template));
        foreach (var contact in student.Contacts.Where(c => !c.InvalidSince.HasValue).OrderBy(c => c.Name)) Contacts.Add(new(contact));
        foreach (var membership in memberships.GetByStudent(student.Id))
@@ -45,10 +53,21 @@ public partial class CreateLetterDialogViewModel : ObservableObject
        RefreshValidation();
    }

-    partial void OnSelectedTemplateChanged(LetterTemplateChoice? value) { OnPropertyChanged(nameof(SuggestedFileName)); RefreshValidation(); }
+    partial void OnSelectedTemplateChanged(LetterTemplateChoice? value)
+    {
+        OnPropertyChanged(nameof(SuggestedFileName));
+        UsesAttendanceCalendar = TemplateUsesAttendanceCalendar(value);
+        AttendanceCalendarConfigured = false;
+        ResetAttendanceCalendarOptions();
+        RefreshValidation();
+    }
    partial void OnSelectedContactChanged(LetterContactChoice? value) => RefreshValidation();
    partial void OnSelectedGroupChanged(LetterGroupChoice? value) => RefreshValidation();
-    partial void OnLetterDateChanged(DateTimeOffset? value) => RefreshValidation();
+    partial void OnLetterDateChanged(DateTimeOffset? value)
+    {
+        if (!AttendanceCalendarConfigured) ResetAttendanceCalendarOptions();
+        RefreshValidation();
+    }
    partial void OnLetterTextChanged(string value) => RefreshValidation();
    partial void OnTeacherNameChanged(string value) => RefreshValidation();

@@ -91,7 +110,60 @@ public partial class CreateLetterDialogViewModel : ObservableObject

    private IReadOnlyDictionary<string, PlaceholderValue> BuildValues() => LetterPlaceholderBuilder.BuildStandardValues(
        _student, SelectedContact?.Model, SelectedGroup?.Model,
-        DateOnly.FromDateTime((LetterDate ?? DateTimeOffset.Now).LocalDateTime), LetterText, TeacherName);
+        DateOnly.FromDateTime((LetterDate ?? DateTimeOffset.Now).LocalDateTime), LetterText, TeacherName,
+        UsesAttendanceCalendar ? _attendanceCalendarFactory?.Invoke(_attendanceCalendarOptions) : null);
+
+    public AttendanceCalendarOptions GetAttendanceCalendarOptions() => _attendanceCalendarOptions;
+
+    public void SetAttendanceCalendarOptions(AttendanceCalendarOptions options)
+    {
+        _attendanceCalendarOptions = options with { StartMonth = options.NormalizedStartMonth,
+            MonthCount = options.NormalizedMonthCount };
+        AttendanceCalendarConfigured = true;
+        AttendanceCalendarSummary = FormatAttendanceCalendarSummary(_attendanceCalendarOptions);
+        RefreshValidation();
+    }
+
+    private void ResetAttendanceCalendarOptions()
+    {
+        var date = DateOnly.FromDateTime((LetterDate ?? DateTimeOffset.Now).LocalDateTime);
+        _attendanceCalendarOptions = new AttendanceCalendarOptions(new(date.Year, date.Month, 1), 1);
+        AttendanceCalendarSummary = FormatAttendanceCalendarSummary(_attendanceCalendarOptions);
+    }
+
+    private bool TemplateUsesAttendanceCalendar(LetterTemplateChoice? choice)
+    {
+        if (choice is null) return false;
+        try
+        {
+            var loaded = _templates.Load(choice.Model);
+            return UsesPlaceholder(loaded.Layout) ||
+                   (loaded.ContinuationLayout is not null && UsesPlaceholder(loaded.ContinuationLayout));
+        }
+        catch (Exception ex) when (ex is IOException or InvalidDataException or TemplateValidationException)
+        {
+            return false;
+        }
+    }
+
+    private static bool UsesPlaceholder(TemplateLayout layout) =>
+        layout.Elements.Concat(layout.PageTemplates.SelectMany(p => p.Elements))
+            .Concat(layout.ContentFlows.SelectMany(f => f.Elements))
+            .Any(e => e is DrawBoxElement { Placeholder: StudentAttendanceCalendarDrawingBuilder.PlaceholderName }
+                   or FlowDrawBoxElement { Placeholder: StudentAttendanceCalendarDrawingBuilder.PlaceholderName });
+
+    private static string FormatAttendanceCalendarSummary(AttendanceCalendarOptions options)
+    {
+        var month = options.NormalizedStartMonth.ToString("MMMM yyyy",
+            System.Globalization.CultureInfo.GetCultureInfo("de-DE"));
+        var size = options.Size switch
+        {
+            AttendanceCalendarSize.Small => "Klein",
+            AttendanceCalendarSize.Large => "Groß",
+            _ => "Standard",
+        };
+        return $"Ab {month} · {options.NormalizedMonthCount} Monat{(options.NormalizedMonthCount == 1 ? "" : "e")} · {size}";
+    }

    private static bool IsEmpty(PlaceholderValue value) => LetterPlaceholderBuilder.IsEmpty(value);
    private static string SanitizeFileName(string value)
@@ -436,6 +436,11 @@
                              Background="Transparent" BorderThickness="0" Padding="6,2"
                              Foreground="{DynamicResource AppAccentTextBrush}"/>
                    </Grid>
+                    <ComboBox ItemsSource="{Binding CalendarScopes}"
+                              SelectedItem="{Binding SelectedCalendarScope, Mode=TwoWay}"
+                              DisplayMemberBinding="{Binding DisplayName}"
+                              HorizontalAlignment="Stretch"
+                              AutomationProperties.Name="Schüler für Monatskalender auswählen"/>
                    <ItemsControl ItemsSource="{Binding CompactMonthDays}" HorizontalAlignment="Center">
                      <ItemsControl.ItemsPanel>
                        <ItemsPanelTemplate><UniformGrid Columns="7"/></ItemsPanelTemplate>
@@ -0,0 +1,39 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:vm="clr-namespace:LehrerApp.Desktop.ViewModels.Students"
+        xmlns:conv="clr-namespace:LehrerApp.Desktop.Converters"
+        x:Class="LehrerApp.Desktop.Views.Students.AttendanceCalendarConfigurationDialog"
+        x:DataType="vm:AttendanceCalendarConfigurationViewModel"
+        Title="Anwesenheitskalender konfigurieren" Width="440" Height="360"
+        CanResize="False" WindowStartupLocation="CenterOwner">
+  <Grid RowDefinitions="*,Auto" Margin="24,20">
+    <StackPanel Spacing="16">
+      <TextBlock Text="Anwesenheitskalender" Classes="dialogtitle"/>
+      <TextBlock Text="Diese Angaben steuern den dynamischen Kalender im Elternbrief. Der Starttag wird automatisch auf den ersten Tag des gewählten Monats gesetzt."
+                 FontSize="12" Opacity="0.65" TextWrapping="Wrap"/>
+      <StackPanel Spacing="4">
+        <TextBlock Text="Erster Monat" FontSize="12" Opacity="0.7"/>
+        <CalendarDatePicker SelectedDate="{Binding StartMonth, Converter={x:Static conv:DateTimeOffsetToDateTimeConverter.Instance}}"
+                            HorizontalAlignment="Stretch"/>
+      </StackPanel>
+      <Grid ColumnDefinitions="*,12,*">
+        <StackPanel Spacing="4">
+          <TextBlock Text="Anzahl Monate" FontSize="12" Opacity="0.7"/>
+          <ComboBox ItemsSource="{Binding MonthCounts}" SelectedItem="{Binding MonthCount, Mode=TwoWay}"
+                    HorizontalAlignment="Stretch"/>
+        </StackPanel>
+        <StackPanel Grid.Column="2" Spacing="4">
+          <TextBlock Text="Darstellungsgröße" FontSize="12" Opacity="0.7"/>
+          <ComboBox ItemsSource="{Binding Sizes}" SelectedItem="{Binding SelectedSize, Mode=TwoWay}"
+                    DisplayMemberBinding="{Binding DisplayName}" HorizontalAlignment="Stretch"/>
+        </StackPanel>
+      </Grid>
+      <TextBlock Text="Bei mehreren Monaten wächst der Zeicheninhalt nach unten. Für drei große Monate sollte die Vorlage eine ausreichend hohe DRAWBOX oder eine FLOWDRAWBOX verwenden."
+                 FontSize="11" Opacity="0.55" TextWrapping="Wrap"/>
+    </StackPanel>
+    <Grid Grid.Row="1" ColumnDefinitions="*,10,*" Margin="0,18,0,0">
+      <Button Grid.Column="0" Content="Abbrechen" HorizontalAlignment="Stretch" Click="OnCancel"/>
+      <Button Grid.Column="2" Content="Übernehmen" HorizontalAlignment="Stretch" Click="OnApply"/>
+    </Grid>
+  </Grid>
+</Window>
@@ -0,0 +1,12 @@
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+
+namespace LehrerApp.Desktop.Views.Students;
+
+public partial class AttendanceCalendarConfigurationDialog : Window
+{
+    public AttendanceCalendarConfigurationDialog() => InitializeComponent();
+
+    private void OnApply(object? sender, RoutedEventArgs e) => Close(true);
+    private void OnCancel(object? sender, RoutedEventArgs e) => Close(false);
+}
@@ -44,6 +44,17 @@
            <CalendarDatePicker SelectedDate="{Binding LetterDate, Converter={x:Static conv:DateTimeOffsetToDateTimeConverter.Instance}}" HorizontalAlignment="Stretch"/>
          </StackPanel>
        </Grid>
+        <Border IsVisible="{Binding UsesAttendanceCalendar}" BorderBrush="{DynamicResource AppCardBorderBrush}"
+                BorderThickness="1" CornerRadius="6" Padding="12">
+          <Grid ColumnDefinitions="*,Auto">
+            <StackPanel Spacing="3">
+              <TextBlock Text="Anwesenheitskalender im Brief" FontWeight="SemiBold"/>
+              <TextBlock Text="{Binding AttendanceCalendarSummary}" FontSize="12" Opacity="0.65"/>
+            </StackPanel>
+            <Button Grid.Column="1" Content="Konfigurieren …" Click="OnConfigureAttendanceCalendar"
+                    VerticalAlignment="Center"/>
+          </Grid>
+        </Border>
        <StackPanel Spacing="4">
          <TextBlock Text="Brieftext" FontSize="12" Opacity="0.7"/>
          <TextBox Text="{Binding LetterText}" AcceptsReturn="True" TextWrapping="Wrap" MinHeight="110"
@@ -12,6 +12,8 @@ public partial class CreateLetterDialog : Window
    private async void OnGenerate(object? sender, RoutedEventArgs e)
    {
        if (DataContext is not CreateLetterDialogViewModel vm) return;
+        if (vm.UsesAttendanceCalendar && !vm.AttendanceCalendarConfigured &&
+            !await ConfigureAttendanceCalendar(vm)) return;
        var file = await StorageProvider.SaveFilePickerAsync(new FilePickerSaveOptions
        {
            Title = "PDF-Brief speichern",
@@ -23,5 +25,19 @@ public partial class CreateLetterDialog : Window
        Close(file.Path.LocalPath);
    }

+    private async void OnConfigureAttendanceCalendar(object? sender, RoutedEventArgs e)
+    {
+        if (DataContext is CreateLetterDialogViewModel vm) await ConfigureAttendanceCalendar(vm);
+    }
+
+    private async Task<bool> ConfigureAttendanceCalendar(CreateLetterDialogViewModel vm)
+    {
+        var configVm = new AttendanceCalendarConfigurationViewModel(vm.GetAttendanceCalendarOptions());
+        var dialog = new AttendanceCalendarConfigurationDialog { DataContext = configVm };
+        if (!await dialog.ShowDialog<bool>(this)) return false;
+        vm.SetAttendanceCalendarOptions(configVm.BuildResult());
+        return true;
+    }
+
    private void OnCancel(object? sender, RoutedEventArgs e) => Close(null);
 }