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

namespace LehrerApp.Desktop.Tests;

/// Tests für den bisher als Platzhalter existierenden Gruppen-Tab "Dokumentation" (Nutzer-Feedback):
/// listet Dokumentationseinträge aller Gruppen-Schüler, zeigt Einträge aus anderen Lerngruppen
/// standardmäßig mit an (optisch abgesetzt statt versteckt), mit optionalem Filter darauf.
public sealed class GroupDocumentationTabViewModelTests
{
    private static GroupDocumentationTabViewModel BuildVm(
        List<Student> students, List<LearningGroup> groups, FakeDocumentation? docs = null)
    {
        var vm = new GroupDocumentationTabViewModel(docs ?? new FakeDocumentation(),
            new FakeStudents(students), new FakeGroups(groups));
        return vm;
    }

    [Fact]
    public void Initialize_ZeigtEintraegeAllerGruppenschuelerSortiertNachDatumAbsteigend()
    {
        var group = new LearningGroup { Name = "9c" };
        var anna = new Student { FirstName = "Anna", LastName = "Beispiel" };
        var ben = new Student { FirstName = "Ben", LastName = "Muster" };
        var docs = new FakeDocumentation();
        docs.Add(new Documentation { StudentId = anna.Id, GroupId = group.Id, Title = "Alt", Date = new DateOnly(2025, 9, 1) });
        docs.Add(new Documentation { StudentId = ben.Id, GroupId = group.Id, Title = "Neu", Date = new DateOnly(2025, 9, 10) });

        var vm = BuildVm([anna, ben], [group], docs);
        vm.Initialize(group.Id);

        Assert.Equal(2, vm.Entries.Count);
        Assert.Equal("Neu", vm.Entries[0].Model.Title);
        Assert.Equal("Alt", vm.Entries[1].Model.Title);
    }

    [Fact]
    public void Initialize_EintragAusAndererGruppe_WirdMitangezeigtAberAlsFremdMarkiert()
    {
        var group = new LearningGroup { Name = "9c" };
        var otherGroup = new LearningGroup { Name = "Mathematik 9b" };
        var anna = new Student { FirstName = "Anna", LastName = "Beispiel" };
        var docs = new FakeDocumentation();
        docs.Add(new Documentation { StudentId = anna.Id, GroupId = otherGroup.Id, Title = "Aus anderem Kurs", Date = new DateOnly(2025, 9, 1) });

        var vm = BuildVm([anna], [group, otherGroup], docs);
        vm.Initialize(group.Id);

        var entry = Assert.Single(vm.Entries);
        Assert.False(entry.IsOwnGroup);
        Assert.Equal("Mathematik 9b", entry.OtherGroupLabel);
        Assert.True(entry.ContentOpacity < 1.0);
    }

    [Fact]
    public void Initialize_EintragOhneGruppe_GiltAlsEigen()
    {
        var group = new LearningGroup { Name = "9c" };
        var anna = new Student { FirstName = "Anna", LastName = "Beispiel" };
        var docs = new FakeDocumentation();
        docs.Add(new Documentation { StudentId = anna.Id, GroupId = null, Title = "Allgemein", Date = new DateOnly(2025, 9, 1) });

        var vm = BuildVm([anna], [group], docs);
        vm.Initialize(group.Id);

        var entry = Assert.Single(vm.Entries);
        Assert.True(entry.IsOwnGroup);
    }

    [Fact]
    public void OnlyThisGroup_Aktiviert_BlendetEintraegeAusAnderenGruppenAus()
    {
        var group = new LearningGroup { Name = "9c" };
        var otherGroup = new LearningGroup { Name = "Mathematik 9b" };
        var anna = new Student { FirstName = "Anna", LastName = "Beispiel" };
        var docs = new FakeDocumentation();
        docs.Add(new Documentation { StudentId = anna.Id, GroupId = group.Id, Title = "Eigen", Date = new DateOnly(2025, 9, 1) });
        docs.Add(new Documentation { StudentId = anna.Id, GroupId = otherGroup.Id, Title = "Fremd", Date = new DateOnly(2025, 9, 2) });

        var vm = BuildVm([anna], [group, otherGroup], docs);
        vm.Initialize(group.Id);
        vm.OnlyThisGroup = true;

        var entry = Assert.Single(vm.Entries);
        Assert.Equal("Eigen", entry.Model.Title);
    }

    [Fact]
    public void SelectedStudentFilter_AufEinzelnenSchueler_FiltertListe()
    {
        var group = new LearningGroup { Name = "9c" };
        var anna = new Student { FirstName = "Anna", LastName = "Beispiel" };
        var ben = new Student { FirstName = "Ben", LastName = "Muster" };
        var docs = new FakeDocumentation();
        docs.Add(new Documentation { StudentId = anna.Id, GroupId = group.Id, Title = "Anna-Eintrag", Date = new DateOnly(2025, 9, 1) });
        docs.Add(new Documentation { StudentId = ben.Id, GroupId = group.Id, Title = "Ben-Eintrag", Date = new DateOnly(2025, 9, 1) });

        var vm = BuildVm([anna, ben], [group], docs);
        vm.Initialize(group.Id);
        vm.SelectedStudentFilter = vm.StudentFilterOptions.Single(s => s.Id == anna.Id);

        var entry = Assert.Single(vm.Entries);
        Assert.Equal("Anna-Eintrag", entry.Model.Title);
    }

    [Fact]
    public async Task AddDocumentation_SpeichertErgebnisUndLaedtNeu()
    {
        var group = new LearningGroup { Name = "9c" };
        var anna = new Student { FirstName = "Anna", LastName = "Beispiel" };
        var docs = new FakeDocumentation();
        var vm = BuildVm([anna], [group], docs);
        vm.Initialize(group.Id);

        vm.OnEditDocumentation = (groupId, options, editing) =>
        {
            Assert.Equal(group.Id, groupId);
            Assert.Contains(options, o => o.Id == anna.Id);
            Assert.Null(editing);
            return Task.FromResult<Documentation?>(new Documentation
            { StudentId = anna.Id, GroupId = groupId, Title = "Neu", Date = new DateOnly(2025, 9, 1) });
        };

        await vm.AddDocumentationCommand.ExecuteAsync(null);

        var entry = Assert.Single(vm.Entries);
        Assert.Equal("Neu", entry.Model.Title);
    }

    [Fact]
    public async Task DeleteDocumentation_NachBestaetigung_EntferntEintragAusListe()
    {
        var group = new LearningGroup { Name = "9c" };
        var anna = new Student { FirstName = "Anna", LastName = "Beispiel" };
        var docs = new FakeDocumentation();
        docs.Add(new Documentation { StudentId = anna.Id, GroupId = group.Id, Title = "Weg", Date = new DateOnly(2025, 9, 1) });
        var vm = BuildVm([anna], [group], docs);
        vm.Initialize(group.Id);
        vm.OnConfirmDeleteDocumentation = _ => Task.FromResult(true);

        await vm.DeleteDocumentationCommand.ExecuteAsync(vm.Entries[0]);

        Assert.Empty(vm.Entries);
    }
}