using LehrerApp.Core.Models;
using LehrerApp.Core.Services;
using LehrerApp.Desktop.ViewModels.Planning;
using Xunit;

namespace LehrerApp.Desktop.Tests;

public sealed class TimetableSlotDialogViewModelTests
{
    private static SchoolYearService SchoolYear() => new();

    [Fact]
    public void Save_OhneAusgewaehlteGruppe_SetztFehlerUndSpeichertNicht()
    {
        var slots = new FakeTimetableSlots();
        var groups = new FakeGroups([]);
        var vm = new TimetableSlotDialogViewModel(slots, groups, new FakeSubjects([]), SchoolYear(), DayOfWeek.Monday, 1, null);

        vm.SaveCommand.Execute(null);

        Assert.Null(vm.Result);
        Assert.NotEqual("", vm.GroupError);
    }

    [Fact]
    public void Save_MitAusgewaehlterGruppe_LegtNeuenSlotAn()
    {
        var group = new LearningGroup { Name = "Q1 Chemie" };
        var slots = new FakeTimetableSlots();
        var groups = new FakeGroups([group]);
        var vm = new TimetableSlotDialogViewModel(slots, groups, new FakeSubjects([]), SchoolYear(), DayOfWeek.Monday, 1, null)
        {
            SelectedGroupName = "Q1 Chemie", Room = "R204",
        };

        vm.SaveCommand.Execute(null);

        Assert.NotNull(vm.Result);
        Assert.Equal(group.Id, vm.Result!.GroupId);
        Assert.Equal("R204", vm.Result.Room);
        Assert.Single(slots.GetAll());
    }

    [Fact]
    public void Save_BelegteStunde_ZeigtFreundlicheFehlermeldungStattAbsturz()
    {
        var groupA = new LearningGroup { Name = "Q1 Chemie" };
        var groupB = new LearningGroup { Name = "Q1 Physik" };
        var slots = new FakeTimetableSlots();
        slots.Add(new TimetableSlot { GroupId = groupA.Id, Weekday = DayOfWeek.Monday, PeriodNumber = 1 });
        var groups = new FakeGroups([groupA, groupB]);
        var vm = new TimetableSlotDialogViewModel(slots, groups, new FakeSubjects([]), SchoolYear(), DayOfWeek.Monday, 1, null)
        {
            SelectedGroupName = "Q1 Physik",
        };

        vm.SaveCommand.Execute(null);

        Assert.Null(vm.Result);
        Assert.Equal("Diese Stunde ist bereits belegt.", vm.GroupError);
    }

    [Fact]
    public void Delete_BeimBearbeitenEinesVorhandenenSlots_EntferntIhn()
    {
        var group = new LearningGroup { Name = "Q1 Chemie" };
        var slot = new TimetableSlot { GroupId = group.Id, Weekday = DayOfWeek.Monday, PeriodNumber = 1 };
        var slots = new FakeTimetableSlots();
        slots.Add(slot);
        var groups = new FakeGroups([group]);
        var vm = new TimetableSlotDialogViewModel(slots, groups, new FakeSubjects([]), SchoolYear(), DayOfWeek.Monday, 1, slot);

        vm.DeleteCommand.Execute(null);

        Assert.True(vm.Deleted);
        Assert.Empty(slots.GetAll());
    }

    /// Regressionstest für den vom Nutzer gemeldeten Absturz: dieselbe Klasse ("10c") wird in
    /// zwei Fächern unterrichtet und hat deshalb zwei LearningGroup-Datensätze mit demselben
    /// Namen — das Anlegen der Gruppenliste darf dabei nicht mehr mit einer ArgumentException
    /// abstürzen, und beide Gruppen müssen über eindeutige, unterscheidbare Labels wählbar bleiben.
    [Fact]
    public void KonstruktorMitGleichnamigenGruppenInVerschiedenenFaechern_StuerztNichtAbUndBleibtUnterscheidbar()
    {
        var chemie = new Subject { Name = "Chemie" };
        var mathe = new Subject { Name = "Mathematik" };
        var groupChemie = new LearningGroup { Name = "10c", SubjectId = chemie.Id };
        var groupMathe = new LearningGroup { Name = "10c", SubjectId = mathe.Id };
        var groups = new FakeGroups([groupChemie, groupMathe]);
        var subjects = new FakeSubjects([chemie, mathe]);
        var slots = new FakeTimetableSlots();

        var vm = new TimetableSlotDialogViewModel(slots, groups, subjects, SchoolYear(), DayOfWeek.Monday, 1, null);

        Assert.Equal(2, vm.GroupOptions.Length);
        Assert.Equal(vm.GroupOptions.Distinct().Count(), vm.GroupOptions.Length);
        Assert.Contains("10c (Chemie)", vm.GroupOptions);
        Assert.Contains("10c (Mathematik)", vm.GroupOptions);

        vm.SelectedGroupName = "10c (Mathematik)";
        vm.SaveCommand.Execute(null);

        Assert.NotNull(vm.Result);
        Assert.Equal(groupMathe.Id, vm.Result!.GroupId);
    }

    /// Beim Bearbeiten eines bestehenden Slots muss das vorausgewählte Label zur tatsächlich
    /// zugewiesenen Gruppe passen, auch wenn deren Name mehrdeutig ist.
    [Fact]
    public void KonstruktorBeimBearbeiten_WaehltDasLabelDerTatsaechlichZugewiesenenGruppeVor()
    {
        var chemie = new Subject { Name = "Chemie" };
        var mathe = new Subject { Name = "Mathematik" };
        var groupChemie = new LearningGroup { Name = "10c", SubjectId = chemie.Id };
        var groupMathe = new LearningGroup { Name = "10c", SubjectId = mathe.Id };
        var groups = new FakeGroups([groupChemie, groupMathe]);
        var subjects = new FakeSubjects([chemie, mathe]);
        var slot = new TimetableSlot { GroupId = groupChemie.Id, Weekday = DayOfWeek.Monday, PeriodNumber = 1 };
        var slots = new FakeTimetableSlots();
        slots.Add(slot);

        var vm = new TimetableSlotDialogViewModel(slots, groups, subjects, SchoolYear(), DayOfWeek.Monday, 1, slot);

        Assert.Equal("10c (Chemie)", vm.SelectedGroupName);
    }
}