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

namespace LehrerApp.Desktop.Tests;

public sealed class LessonDialogViewModelTests
{
    private static LessonDialogViewModel BuildVm(Guid unitId, Guid groupId, Lesson? editing = null) =>
        new(new FakeLessons(), new FakeShorthandCodes([]), new FakeAlternativeLessonPaths([]),
            unitId, groupId, [], [], editing);

    [Fact]
    public void AddPhase_FuegtZeileMitStandardwertenHinzu()
    {
        var vm = BuildVm(Guid.NewGuid(), Guid.NewGuid());

        vm.AddPhaseCommand.Execute(null);

        Assert.Single(vm.Phases);
        Assert.Equal(5, vm.Phases[0].DurationMinutes);
        Assert.False(vm.Phases[0].HasAlternativePath);
    }

    [Fact]
    public void RemovePhase_EntferntZeileUndAktualisiertGesamtdauer()
    {
        var vm = BuildVm(Guid.NewGuid(), Guid.NewGuid());
        vm.AddPhaseCommand.Execute(null);
        vm.Phases[0].DurationMinutes = 20;

        vm.Phases[0].RemoveCommand.Execute(null);

        Assert.Empty(vm.Phases);
        Assert.Equal("0 Minuten gesamt", vm.TotalDurationDisplay);
    }

    [Fact]
    public void MoveDown_VertauschtReihenfolgeDerPhasen()
    {
        var vm = BuildVm(Guid.NewGuid(), Guid.NewGuid());
        vm.AddPhaseCommand.Execute(null);
        vm.Phases[0].Name = "Einstieg";
        vm.AddPhaseCommand.Execute(null);
        vm.Phases[1].Name = "Erarbeitung";

        vm.Phases[0].MoveDownCommand.Execute(null);

        Assert.Equal("Erarbeitung", vm.Phases[0].Name);
        Assert.Equal("Einstieg", vm.Phases[1].Name);
    }

    [Fact]
    public void Shorthand_IstFreitextOhneErzwungeneVonNachStruktur()
    {
        // Kurzsymbol muss nicht immer ein Materialfluss-Pfeil sein — manchmal nur eine
        // Sozialform ohne Pfeil (z.B. "Plenum", "LDE").
        var vm = BuildVm(Guid.NewGuid(), Guid.NewGuid());
        vm.AddPhaseCommand.Execute(null);
        var phase = vm.Phases[0];

        phase.Shorthand = "Plenum";
        Assert.Equal("Plenum", phase.Shorthand);

        phase.Shorthand = "AB001->S";
        Assert.Equal("AB001->S", phase.Shorthand);
    }

    [Fact]
    public void ShorthandSuggestions_KombiniertKatalogUndBisherigeStundenwerte()
    {
        var codes = new FakeShorthandCodes([new ShorthandCode { Code = "Tb" }, new ShorthandCode { Code = "SH" }]);
        var vm = new LessonDialogViewModel(new FakeLessons(), codes, new FakeAlternativeLessonPaths([]),
            Guid.NewGuid(), Guid.NewGuid(), [], ["Plenum", "LDE", "Tb"], null); // "Tb" doppelt (Katalog + Historie), soll nur einmal erscheinen

        Assert.Equal(["LDE", "Plenum", "SH", "Tb"], vm.ShorthandSuggestions);
    }

    [Fact]
    public void RecomputeTimes_LeitetUhrzeitJePhaseAusBeginnUndKumulierterDauerAb()
    {
        var vm = BuildVm(Guid.NewGuid(), Guid.NewGuid());
        vm.StartTimeText = "12:00";
        vm.AddPhaseCommand.Execute(null);
        vm.Phases[0].DurationMinutes = 15;
        vm.AddPhaseCommand.Execute(null);
        vm.Phases[1].DurationMinutes = 10;

        Assert.Equal("ab 12:00", vm.Phases[0].ComputedTimeDisplay);
        Assert.Equal("ab 12:15", vm.Phases[1].ComputedTimeDisplay);
        Assert.Equal("25 Minuten gesamt", vm.TotalDurationDisplay);
    }

    [Fact]
    public void RecomputeTimes_OhneBeginnBleibtDieUhrzeitanzeigeLeer()
    {
        var vm = BuildVm(Guid.NewGuid(), Guid.NewGuid());
        vm.AddPhaseCommand.Execute(null);
        vm.Phases[0].DurationMinutes = 15;

        Assert.Equal("", vm.Phases[0].ComputedTimeDisplay);
    }

    [Fact]
    public void Save_ErfordertThemaUndGueltigesDatum()
    {
        var vm = BuildVm(Guid.NewGuid(), Guid.NewGuid());
        vm.Topic = ""; vm.DateText = "keinDatum";

        vm.SaveCommand.Execute(null);

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

    [Fact]
    public void Save_UngueltigesBeginnFormatWirdAbgelehnt()
    {
        var vm = BuildVm(Guid.NewGuid(), Guid.NewGuid());
        vm.Topic = "Thema"; vm.DateText = "01.09.2025"; vm.StartTimeText = "nicht-uhrzeit";

        vm.SaveCommand.Execute(null);

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

    [Fact]
    public void Save_SetztUnitIdGroupIdUndUebernimmtPhasenUndBeginn()
    {
        var unitId = Guid.NewGuid();
        var groupId = Guid.NewGuid();
        var lessons = new FakeLessons();
        var vm = new LessonDialogViewModel(lessons, new FakeShorthandCodes([]), new FakeAlternativeLessonPaths([]),
            unitId, groupId, [], [], null)
        {
            Topic = "Brechung", DateText = "01.09.2025", StartTimeText = "11:45",
        };
        vm.AddPhaseCommand.Execute(null);
        vm.Phases[0].Name = "Einstieg";
        vm.Phases[0].DurationMinutes = 10;
        vm.Phases[0].Activity = "Begrüßung";
        vm.Phases[0].Material = "AB01";
        vm.Phases[0].Shorthand = "L->AB01";

        vm.SaveCommand.Execute(null);

        Assert.NotNull(vm.Result);
        Assert.Equal(unitId, vm.Result!.UnitId);
        Assert.Equal(groupId, vm.Result.GroupId);
        Assert.Equal(new TimeOnly(11, 45), vm.Result.StartTime);
        Assert.Single(vm.Result.Phases);
        Assert.Equal("Einstieg", vm.Result.Phases[0].Name);
        Assert.Equal(10, vm.Result.Phases[0].DurationMinutes);
        Assert.Equal("L->AB01", vm.Result.Phases[0].Shorthand);
        Assert.Single(lessons.GetByUnit(unitId));
    }

    [Fact]
    public void HasAlternativePath_AngehaktOeffnetZuweisungUndUebernimmtErgebnis()
    {
        var vm = BuildVm(Guid.NewGuid(), Guid.NewGuid());
        var path = new AlternativeLessonPath { Name = "Kurzversion" };
        vm.OnPickAlternativePath = _ => Task.FromResult<AlternativeLessonPath?>(path);
        vm.AddPhaseCommand.Execute(null);

        vm.Phases[0].HasAlternativePath = true;

        Assert.True(vm.Phases[0].HasAlternativePath);
        Assert.Equal("Kurzversion", vm.Phases[0].AlternativePathName);
        Assert.Equal(path.Id, vm.Phases[0].AlternativePathId);
    }

    [Fact]
    public void HasAlternativePath_AbbruchDerZuweisungLaesstEsUnangehakt()
    {
        var vm = BuildVm(Guid.NewGuid(), Guid.NewGuid());
        vm.OnPickAlternativePath = _ => Task.FromResult<AlternativeLessonPath?>(null); // abgebrochen
        vm.AddPhaseCommand.Execute(null);

        vm.Phases[0].HasAlternativePath = true;

        Assert.False(vm.Phases[0].HasAlternativePath);
        Assert.Null(vm.Phases[0].AlternativePathId);
    }

    [Fact]
    public void HasAlternativePath_AbwaehlenEntferntZuordnungOhneDialogZuOeffnen()
    {
        var vm = BuildVm(Guid.NewGuid(), Guid.NewGuid());
        var path = new AlternativeLessonPath { Name = "Kurzversion" };
        var dialogCalls = 0;
        vm.OnPickAlternativePath = _ => { dialogCalls++; return Task.FromResult<AlternativeLessonPath?>(path); };
        vm.AddPhaseCommand.Execute(null);
        vm.Phases[0].HasAlternativePath = true; // zuweisen -> 1 Dialogaufruf

        vm.Phases[0].HasAlternativePath = false; // abwählen -> kein weiterer Dialogaufruf

        Assert.Equal(1, dialogCalls);
        Assert.False(vm.Phases[0].HasAlternativePath);
        Assert.Equal("", vm.Phases[0].AlternativePathName);
        Assert.Null(vm.Phases[0].AlternativePathId);
    }

    [Fact]
    public void Save_UebernimmtZugewiesenenAlternativePfad()
    {
        var vm = BuildVm(Guid.NewGuid(), Guid.NewGuid());
        var path = new AlternativeLessonPath { Name = "Kurzversion" };
        vm.OnPickAlternativePath = _ => Task.FromResult<AlternativeLessonPath?>(path);
        vm.Topic = "Thema"; vm.DateText = "01.09.2025";
        vm.AddPhaseCommand.Execute(null);
        vm.Phases[0].HasAlternativePath = true;

        vm.SaveCommand.Execute(null);

        Assert.Equal(path.Id, vm.Result!.Phases[0].AlternativePathId);
    }

    [Fact]
    public void AddPhaseInternal_LoestBestehendeZuordnungBeimBearbeitenAuf()
    {
        var path = new AlternativeLessonPath { Name = "Kurzversion" };
        var alternativePaths = new FakeAlternativeLessonPaths([path]);
        var editing = new Lesson
        {
            Topic = "Thema", Date = new DateOnly(2025, 9, 1),
            Phases = [new LessonPhaseStep { Name = "Einstieg", AlternativePathId = path.Id }],
        };

        var vm = new LessonDialogViewModel(new FakeLessons(), new FakeShorthandCodes([]), alternativePaths,
            Guid.NewGuid(), Guid.NewGuid(), [], [], editing);

        Assert.True(vm.Phases[0].HasAlternativePath);
        Assert.Equal("Kurzversion", vm.Phases[0].AlternativePathName);
    }
}