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

namespace LehrerApp.Desktop.Tests;

public sealed class LessonViewerViewModelTests
{
    [Fact]
    public void OhneAlternativenGibtEsGenauEineHauptwegGruppe()
    {
        var lesson = new Lesson
        {
            Topic = "Brechung", Date = new DateOnly(2025, 9, 1), StartTime = new TimeOnly(11, 45),
            Phases =
            [
                new LessonPhaseStep { Name = "Einstieg", DurationMinutes = 5, Activity = "Begrüßung" },
                new LessonPhaseStep { Name = "Erarbeitung", DurationMinutes = 15, Activity = "AB01 bearbeiten" },
            ],
        };

        var vm = new LessonViewerViewModel(lesson, new FakeAlternativeLessonPaths([]));

        Assert.False(vm.HasAlternatives);
        var group = Assert.Single(vm.PhaseGroups);
        Assert.Equal("Hauptweg", group.Label);
        Assert.True(group.IsMainPath);
        Assert.Equal(2, group.Phases.Count);
        Assert.Equal("ab 11:45", group.Phases[0].TimeDisplay);
        Assert.Equal("ab 11:50", group.Phases[1].TimeDisplay);
    }

    [Fact]
    public void OhneBeginnBleibtDieUhrzeitanzeigeLeer()
    {
        var lesson = new Lesson
        {
            Topic = "Brechung", Date = new DateOnly(2025, 9, 1),
            Phases = [new LessonPhaseStep { Name = "Einstieg", DurationMinutes = 5 }],
        };

        var vm = new LessonViewerViewModel(lesson, new FakeAlternativeLessonPaths([]));

        Assert.Equal("", vm.PhaseGroups[0].Phases[0].TimeDisplay);
        Assert.Equal("–", vm.StartTimeDisplay);
    }

    [Fact]
    public void GruppiertPhasenNachAlternativePathUndHauptwegStehtImmerZuerst()
    {
        var kurzversion = new AlternativeLessonPath { Name = "Kurzversion", Description = "Bei Zeitmangel." };
        var alternativePaths = new FakeAlternativeLessonPaths([kurzversion]);
        var lesson = new Lesson
        {
            Topic = "Brechung", Date = new DateOnly(2025, 9, 1), StartTime = new TimeOnly(12, 0),
            Phases =
            [
                new LessonPhaseStep { Name = "Einstieg", DurationMinutes = 5, AlternativePathId = kurzversion.Id },
                new LessonPhaseStep { Name = "Einstieg", DurationMinutes = 5 }, // Hauptweg, aber nach der Alternative angelegt
                new LessonPhaseStep { Name = "Sicherung (kurz)", DurationMinutes = 5, AlternativePathId = kurzversion.Id },
                new LessonPhaseStep { Name = "Erarbeitung", DurationMinutes = 20 },
            ],
        };

        var vm = new LessonViewerViewModel(lesson, alternativePaths);

        Assert.True(vm.HasAlternatives);
        Assert.Equal(2, vm.PhaseGroups.Count);
        Assert.Equal("Hauptweg", vm.PhaseGroups[0].Label); // steht zuerst trotz Reihenfolge im Modell
        Assert.True(vm.PhaseGroups[0].IsMainPath);
        Assert.Null(vm.PhaseGroups[0].Description);
        Assert.Equal(2, vm.PhaseGroups[0].Phases.Count);
        Assert.Equal("Kurzversion", vm.PhaseGroups[1].Label);
        Assert.False(vm.PhaseGroups[1].IsMainPath);
        Assert.Equal("Bei Zeitmangel.", vm.PhaseGroups[1].Description);
        Assert.Equal(2, vm.PhaseGroups[1].Phases.Count);
    }

    [Fact]
    public void JedeGruppeBerechnetIhreEigeneUhrzeitAbStundenbeginn()
    {
        var planB = new AlternativeLessonPath { Name = "Plan B" };
        var alternativePaths = new FakeAlternativeLessonPaths([planB]);
        var lesson = new Lesson
        {
            Topic = "Brechung", Date = new DateOnly(2025, 9, 1), StartTime = new TimeOnly(12, 0),
            Phases =
            [
                new LessonPhaseStep { Name = "Einstieg", DurationMinutes = 5 },
                new LessonPhaseStep { Name = "Vertiefung", DurationMinutes = 30, AlternativePathId = planB.Id },
            ],
        };

        var vm = new LessonViewerViewModel(lesson, alternativePaths);

        // Beide Gruppen starten unabhängig voneinander bei Stundenbeginn, nicht hintereinander.
        Assert.Equal("ab 12:00", vm.PhaseGroups[0].Phases[0].TimeDisplay);
        Assert.Equal("ab 12:00", vm.PhaseGroups[1].Phases[0].TimeDisplay);
    }
}