LehrerApp/LehrerApp.Desktop.Tests/TeachingModeOutstandingHomeworkViewModelTests.cs

using LehrerApp.Core.Models;
using LehrerApp.Desktop.ViewModels.Groups;
using Xunit;

namespace LehrerApp.Desktop.Tests;

public sealed class TeachingModeOutstandingHomeworkViewModelTests
{
    [Fact]
    public void Refresh_ZeigtJungeOffeneNachreichungenUndFiltertAktuellAbwesende()
    {
        var date = new DateOnly(2026, 9, 25);
        var group = new LearningGroup { Name = "10c Chemie" };
        var amelia = new Student { FirstName = "Amelia", LastName = "Gerste" };
        var ben = new Student { FirstName = "Ben", LastName = "Muster" };
        var carl = new Student { FirstName = "Carl", LastName = "Beispiel" };
        var oldMember = new Student { FirstName = "Dana", LastName = "Alt" };
        var previous = new ParticipationSession { GroupId = group.Id, Date = date.AddDays(-5) };
        var older = new ParticipationSession { GroupId = group.Id, Date = date.AddDays(-130) };
        var current = new ParticipationSession { GroupId = group.Id, Date = date };
        var memberships = new FakeMemberships([
            new GroupMembership { StudentId = amelia.Id, GroupId = group.Id },
            new GroupMembership { StudentId = ben.Id, GroupId = group.Id },
            new GroupMembership { StudentId = carl.Id, GroupId = group.Id },
            new GroupMembership { StudentId = oldMember.Id, GroupId = group.Id,
                Period = MembershipPeriod.Custom, JoinedAt = date.AddDays(-30), LeftAt = date.AddDays(-1) },
        ]);
        var entries = new FakeEntries();
        entries.Add(new ParticipationEntry { SessionId = previous.Id, StudentId = amelia.Id,
            Homework = HomeworkStatus.MissingOverdue });
        var benEntry = new ParticipationEntry { SessionId = previous.Id, StudentId = ben.Id,
            Homework = HomeworkStatus.MissingOpen };
        entries.Add(benEntry);
        entries.Add(new ParticipationEntry { SessionId = previous.Id, StudentId = carl.Id,
            Homework = HomeworkStatus.SubmittedLate });
        entries.Add(new ParticipationEntry { SessionId = previous.Id, StudentId = oldMember.Id,
            Homework = HomeworkStatus.MissingOverdue });
        entries.Add(new ParticipationEntry { SessionId = older.Id, StudentId = ben.Id,
            Homework = HomeworkStatus.MissingOverdue });
        entries.Add(new ParticipationEntry { SessionId = current.Id, StudentId = ben.Id,
            Attendance = AttendanceStatus.Present });
        entries.Add(new ParticipationEntry { SessionId = current.Id, StudentId = amelia.Id,
            Attendance = AttendanceStatus.ExcusePending });

        var vm = new TeachingModeOutstandingHomeworkViewModel(group.Id, date,
            new FakeStudents([amelia, ben, carl, oldMember]), memberships,
            new FakeSessions([previous, older, current]), entries);
        vm.SetCurrentSessionId(current.Id);
        vm.IsExpanded = true;

        Assert.Equal(ben.FullName, Assert.Single(vm.Rows).StudentName);
        Assert.Equal("Offene Nachreichungen (1)", vm.Header);
        vm.IncludeAbsentStudents = true;
        Assert.Equal(2, vm.Rows.Count);
        Assert.Contains(vm.Rows, r => r.StudentName == amelia.FullName &&
            r.Status == HomeworkStatus.MissingOverdue);

        vm.IncludeAbsentStudents = false;
        var currentAmelia = entries.GetBySessionAndStudent(current.Id, amelia.Id)!;
        currentAmelia.Attendance = AttendanceStatus.Present;
        entries.Save(currentAmelia);
        vm.Refresh();
        Assert.Equal(2, vm.Rows.Count);

        benEntry.Homework = HomeworkStatus.SubmittedLate;
        entries.Save(benEntry);
        vm.Refresh();
        Assert.Equal(amelia.FullName, Assert.Single(vm.Rows).StudentName);
    }

    [Theory]
    [InlineData(HomeworkStatus.MissingOpen, "submitted", HomeworkStatus.SubmittedLate)]
    [InlineData(HomeworkStatus.MissingOpen, "final", HomeworkStatus.MissingOverdue)]
    [InlineData(HomeworkStatus.MissingOpen, "partial", HomeworkStatus.PartialMissingOverdue)]
    [InlineData(HomeworkStatus.MissingOverdue, "submitted", HomeworkStatus.SubmittedLate)]
    [InlineData(HomeworkStatus.PartiallyCompleted, "submitted", HomeworkStatus.PartialSubmittedLate)]
    [InlineData(HomeworkStatus.PartiallyCompleted, "final", HomeworkStatus.PartialMissingOverdue)]
    [InlineData(HomeworkStatus.PartialMissingOverdue, "submitted", HomeworkStatus.PartialSubmittedLate)]
    public void Zeilenaktionen_SetzenPassendenEndstatus(HomeworkStatus start, string action, HomeworkStatus expected)
    {
        var (vm, entries, entry) = CreateSingle(start);
        vm.Refresh();
        var row = Assert.Single(vm.Rows);

        var command = action switch
        {
            "submitted" => row.MarkSubmittedCommand,
            "final" => row.MarkFinalCommand,
            _ => row.MarkPartialCommand,
        };
        command.Execute(null);

        var saved = entries.GetBySessionAndStudent(entry.SessionId, entry.StudentId)!;
        Assert.Equal(expected, saved.Homework);
        Assert.Equal(HomeworkDisplay.CountsAsMissing(expected), saved.HomeworkMissing);
        Assert.Equal(HomeworkDisplay.CountsAsMissing(expected), vm.Rows.Count == 1);
    }

    [Fact]
    public void Zeilenaktionen_BietenNurSinnvolleOptionenAn()
    {
        var (vm, _, _) = CreateSingle(HomeworkStatus.MissingOverdue);
        vm.Refresh();
        var overdue = Assert.Single(vm.Rows);
        Assert.False(overdue.CanMarkFinal);
        Assert.True(overdue.CanMarkPartial);

        (vm, _, _) = CreateSingle(HomeworkStatus.PartiallyCompleted);
        vm.Refresh();
        var partial = Assert.Single(vm.Rows);
        Assert.True(partial.CanMarkFinal);
        Assert.False(partial.CanMarkPartial);

        (vm, _, _) = CreateSingle(HomeworkStatus.MissingOpen, isReadOnly: true);
        vm.Refresh();
        Assert.False(Assert.Single(vm.Rows).CanEdit);
    }

    [Fact]
    public void Undo_StelltVorherigenStatusWiederHer()
    {
        var (vm, entries, entry) = CreateSingle(HomeworkStatus.MissingOpen);
        var changed = 0;
        vm.OnHomeworkChanged = () => changed++;
        vm.Refresh();
        Assert.False(vm.UndoCommand.CanExecute(null));

        vm.Rows[0].MarkSubmittedCommand.Execute(null);
        Assert.Empty(vm.Rows);
        Assert.NotNull(vm.LastChangeLabel);
        Assert.True(vm.UndoCommand.CanExecute(null));

        vm.UndoCommand.Execute(null);
        var saved = entries.GetBySessionAndStudent(entry.SessionId, entry.StudentId)!;
        Assert.Equal(HomeworkStatus.MissingOpen, saved.Homework);
        Assert.True(saved.HomeworkMissing);
        Assert.Single(vm.Rows);
        Assert.Null(vm.LastChangeLabel);
        Assert.False(vm.UndoCommand.CanExecute(null));
        Assert.Equal(2, changed);
    }

    private static (TeachingModeOutstandingHomeworkViewModel Vm, FakeEntries Entries, ParticipationEntry Entry)
        CreateSingle(HomeworkStatus status, bool isReadOnly = false)
    {
        var date = new DateOnly(2026, 9, 25);
        var group = new LearningGroup { Name = "10c Chemie" };
        var student = new Student { FirstName = "Ben", LastName = "Muster" };
        var session = new ParticipationSession { GroupId = group.Id, Date = date.AddDays(-5) };
        var entries = new FakeEntries();
        var entry = new ParticipationEntry { SessionId = session.Id, StudentId = student.Id,
            Homework = status, HomeworkMissing = true };
        entries.Add(entry);
        var vm = new TeachingModeOutstandingHomeworkViewModel(group.Id, date,
            new FakeStudents([student]),
            new FakeMemberships([new GroupMembership { StudentId = student.Id, GroupId = group.Id }]),
            new FakeSessions([session]), entries, isReadOnly);
        return (vm, entries, entry);
    }
}