LehrerApp/LehrerApp.Desktop.Tests/CreateLetterDialogViewModelTests.cs

using LehrerApp.Core.Models;
using LehrerApp.Desktop.Services;
using LehrerApp.Desktop.ViewModels.Students;
using LehrerApp.Templating;
using Xunit;

namespace LehrerApp.Desktop.Tests;

public sealed class CreateLetterDialogViewModelTests : IDisposable
{
    private readonly string _directory = Path.Combine(Path.GetTempPath(), $"lehrerapp-letter-vm-tests-{Guid.NewGuid():N}");
    public CreateLetterDialogViewModelTests() => Directory.CreateDirectory(_directory);

    [Fact]
    public void OhneVorlage_KannKeinenBriefErzeugen()
    {
        var vm = Build(StudentWithContact("Sehr geehrte Frau Muster,"), new TemplateStore(_directory));
        Assert.False(vm.CanGenerate);
        Assert.Contains(vm.Issues, i => i.Message.Contains("Vorlage", StringComparison.OrdinalIgnoreCase));
    }

    [Fact]
    public void VerwendeteBriefanredeFehlt_BlockiertErzeugung()
    {
        var vm = Build(StudentWithContact(null), StoreWithTemplate(
            new PlaceholderDefinition("Anrede", PlaceholderType.Text, true)));
        Assert.False(vm.CanGenerate);
        Assert.Contains(vm.Issues, i => i.Message.Contains("Anrede", StringComparison.OrdinalIgnoreCase));
    }

    [Fact]
    public void VollstaendigeDaten_ErzeugenFlachesPdf()
    {
        var store = StoreWithTemplate(new PlaceholderDefinition("Anrede", PlaceholderType.Text, true),
            new PlaceholderDefinition("Datum", PlaceholderType.Date, true),
            new PlaceholderDefinition("Brieftext", PlaceholderType.Multiline, true));
        var vm = Build(StudentWithContact("Sehr geehrte Frau Muster,"), store);
        vm.LetterText = "Dies ist der Inhalt.";
        var output = Path.Combine(_directory, "Brief.pdf");

        Assert.True(vm.Generate(output));
        Assert.Equal("%PDF", System.Text.Encoding.ASCII.GetString(File.ReadAllBytes(output), 0, 4));
    }

    [Fact]
    public void KonstanterPflichttext_BenoetigtKeineExterneEingabe()
    {
        var store = StoreWithTemplate(new PlaceholderDefinition("Brieftext", PlaceholderType.Multiline,
            Required: true, IsConstant: true, ConstantValue: "Fest im Vorlagenpaket"));
        var vm = Build(StudentWithContact("Sehr geehrte Frau Muster,"), store);
        var output = Path.Combine(_directory, "Konstant.pdf");

        Assert.True(vm.CanGenerate);
        Assert.True(vm.Generate(output));
        Assert.Equal("%PDF", System.Text.Encoding.ASCII.GetString(File.ReadAllBytes(output), 0, 4));
    }

    [Fact]
    public void AdvancedContent_Anwesenheitskalender_WirdAlsDrawingGerendert()
    {
        var store = StoreWithTemplate(new PlaceholderDefinition(
            StudentAttendanceCalendarDrawingBuilder.PlaceholderName, PlaceholderType.Drawing, true));
        var drawing = StudentAttendanceCalendarDrawingBuilder.Build("Lena Beispiel", new DateOnly(2026, 9, 1), [], []);
        var vm = new CreateLetterDialogViewModel(StudentWithContact("Sehr geehrte Frau Muster,"), store,
            new QuestTemplateRenderer(), new FakeMemberships([]), new FakeGroups([]), _ => drawing);
        var output = Path.Combine(_directory, "Kalender.pdf");

        Assert.True(vm.UsesAttendanceCalendar);
        vm.SetAttendanceCalendarOptions(new AttendanceCalendarOptions(
            new DateOnly(2026, 8, 19), 3, AttendanceCalendarSize.Large));
        Assert.True(vm.AttendanceCalendarConfigured);
        Assert.Contains("August 2026", vm.AttendanceCalendarSummary);
        Assert.Contains("3 Monate", vm.AttendanceCalendarSummary);
        Assert.Contains("Groß", vm.AttendanceCalendarSummary);
        Assert.True(vm.Generate(output));
        Assert.Equal("%PDF", System.Text.Encoding.ASCII.GetString(File.ReadAllBytes(output), 0, 4));
    }

    private CreateLetterDialogViewModel Build(Student student, TemplateStore store) =>
        new(student, store, new QuestTemplateRenderer(), new FakeMemberships([]), new FakeGroups([]));

    private TemplateStore StoreWithTemplate(params PlaceholderDefinition[] definitions)
    {
        var source = Path.Combine(_directory, $"{Guid.NewGuid():N}.lavorlage");
        var manifest = new TemplateManifest { Id = $"brief-{Guid.NewGuid():N}", Name = "Elternbrief", Placeholders = [.. definitions] };
        var lines = new List<string> { "PAGE 210 297 mm" };
        var y = 20;
        foreach (var definition in definitions)
        {
            var element = definition.Type switch
            {
                PlaceholderType.Multiline => "TEXTBOX",
                PlaceholderType.Drawing => "DRAWBOX",
                _ => "TEXT",
            };
            lines.Add(element switch
            {
                "TEXTBOX" => $"TEXTBOX 20 {y} 170 80 ${definition.Name}",
                "DRAWBOX" => $"DRAWBOX 20 {y} 170 80 ${definition.Name}",
                _ => $"TEXT 20 {y} ${definition.Name}",
            });
            y += 20;
        }
        TemplatePackage.Create(source, manifest, string.Join('\n', lines), new Dictionary<string, byte[]>());
        var store = new TemplateStore(Path.Combine(_directory, $"store-{Guid.NewGuid():N}")); store.Import(source); return store;
    }

    private static Student StudentWithContact(string? salutation) => new()
    {
        FirstName = "Lena", LastName = "Beispiel",
        Contacts = [new Contact { Name = "Frau Muster", Relation = "Mutter", LetterSalutation = salutation,
            Street = "Hauptstraße 1", PostalCode = "12345", City = "Musterstadt" }],
    };
    public void Dispose() { if (Directory.Exists(_directory)) Directory.Delete(_directory, true); }
}