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

namespace LehrerApp.Desktop.Tests;

public sealed class WorkTaskListViewModelTests
{
    [Fact]
    public void Load_BlendetErledigteAufgabenStandardmaessigAus()
    {
        var tasks = new FakeWorkTasks();
        tasks.Add(new WorkTask { Title = "Offen", Status = WorkTaskStatus.Open });
        tasks.Add(new WorkTask { Title = "Erledigt", Status = WorkTaskStatus.Done });
        var vm = new WorkTaskListViewModel(tasks, new FakeGroups([]));

        Assert.Single(vm.Tasks);
        Assert.Equal("Offen", vm.Tasks[0].Title);
    }

    [Fact]
    public void StatusFilter_Alle_ZeigtAuchErledigteAufgaben()
    {
        var tasks = new FakeWorkTasks();
        tasks.Add(new WorkTask { Title = "Erledigt", Status = WorkTaskStatus.Done });
        var vm = new WorkTaskListViewModel(tasks, new FakeGroups([]))
        {
            StatusFilter = WorkTaskListViewModel.AllFilter,
        };

        Assert.Single(vm.Tasks);
    }

    [Fact]
    public void CategoryFilter_FiltertNachKategorie()
    {
        var tasks = new FakeWorkTasks();
        tasks.Add(new WorkTask { Title = "Korrektur", Category = TaskCategory.Correction });
        tasks.Add(new WorkTask { Title = "Vorbereitung", Category = TaskCategory.Preparation });
        var vm = new WorkTaskListViewModel(tasks, new FakeGroups([]))
        {
            CategoryFilter = TaskCategoryDisplay.Label(TaskCategory.Correction),
        };

        Assert.Single(vm.Tasks);
        Assert.Equal("Korrektur", vm.Tasks[0].Title);
    }

    [Fact]
    public void GroupFilter_OhneGruppe_ZeigtNurAufgabenOhneGroupId()
    {
        var group = new LearningGroup { Name = "8a" };
        var tasks = new FakeWorkTasks();
        tasks.Add(new WorkTask { Title = "Mit Gruppe", GroupId = group.Id });
        tasks.Add(new WorkTask { Title = "Ohne Gruppe", GroupId = null });
        var vm = new WorkTaskListViewModel(tasks, new FakeGroups([group]))
        {
            GroupFilter = WorkTaskListViewModel.NoGroupFilter,
        };

        Assert.Single(vm.Tasks);
        Assert.Equal("Ohne Gruppe", vm.Tasks[0].Title);
    }

    [Fact]
    public void CycleStatus_WechseltVonOffenNachInBearbeitung()
    {
        var tasks = new FakeWorkTasks();
        tasks.Add(new WorkTask { Title = "T", Status = WorkTaskStatus.Open });
        var vm = new WorkTaskListViewModel(tasks, new FakeGroups([]))
        {
            StatusFilter = WorkTaskListViewModel.AllFilter,
        };

        vm.CycleStatusCommand.Execute(vm.Tasks[0]);

        Assert.Equal(WorkTaskStatus.InProgress, vm.Tasks[0].Model.Status);
    }

    [Fact]
    public void CycleStatus_VonErledigtSpringtZurueckZuOffen()
    {
        var tasks = new FakeWorkTasks();
        tasks.Add(new WorkTask { Title = "T", Status = WorkTaskStatus.Done });
        var vm = new WorkTaskListViewModel(tasks, new FakeGroups([]))
        {
            StatusFilter = WorkTaskListViewModel.AllFilter,
        };

        vm.CycleStatusCommand.Execute(vm.Tasks[0]);

        Assert.Equal(WorkTaskStatus.Open, vm.Tasks[0].Model.Status);
    }

    [Fact]
    public void DeleteTask_EntferntAufgabeAusDerListe()
    {
        var tasks = new FakeWorkTasks();
        tasks.Add(new WorkTask { Title = "T" });
        var vm = new WorkTaskListViewModel(tasks, new FakeGroups([]));

        vm.DeleteTaskCommand.Execute(vm.Tasks[0]);

        Assert.Empty(vm.Tasks);
    }

    [Fact]
    public async Task AddTask_RuftOnEditTaskAufUndSpeichertErgebnis()
    {
        var tasks = new FakeWorkTasks();
        var vm = new WorkTaskListViewModel(tasks, new FakeGroups([]));
        vm.OnEditTask = _ => Task.FromResult<WorkTask?>(new WorkTask { Title = "Neu" });

        await vm.AddTaskCommand.ExecuteAsync(null);

        Assert.Single(vm.Tasks);
        Assert.Equal("Neu", vm.Tasks[0].Title);
    }

    [Fact]
    public void Tasks_SindNachFaelligkeitSortiertUnbefristeteAmEnde()
    {
        var tasks = new FakeWorkTasks();
        tasks.Add(new WorkTask { Title = "Ohne Frist", DueDate = null });
        tasks.Add(new WorkTask { Title = "Spät fällig", DueDate = DateOnly.FromDateTime(DateTime.Today.AddDays(10)) });
        tasks.Add(new WorkTask { Title = "Bald fällig", DueDate = DateOnly.FromDateTime(DateTime.Today.AddDays(1)) });
        var vm = new WorkTaskListViewModel(tasks, new FakeGroups([]));

        Assert.Equal(["Bald fällig", "Spät fällig", "Ohne Frist"], vm.Tasks.Select(t => t.Title));
    }
}

public sealed class AddEditWorkTaskDialogViewModelTests
{
    [Fact]
    public void Save_OhneTitel_SetztFehlerUndErzeugtKeinResult()
    {
        var vm = new AddEditWorkTaskDialogViewModel(null, []);

        vm.SaveCommand.Execute(null);

        Assert.Null(vm.Result);
        Assert.NotEmpty(vm.TitleError);
    }

    [Fact]
    public void Save_MitGueltigenDaten_ErzeugtWorkTask()
    {
        var group = new LearningGroup { Name = "8a" };
        var vm = new AddEditWorkTaskDialogViewModel(null, [group])
        {
            Title = "Klausur korrigieren",
            SelectedCategory = TaskCategoryDisplay.Label(TaskCategory.Correction),
            SelectedGroup = group,
            DueDateText = "24.12.2026",
            EstimatedMinutesText = "90",
        };

        vm.SaveCommand.Execute(null);

        Assert.NotNull(vm.Result);
        Assert.Equal("Klausur korrigieren", vm.Result!.Title);
        Assert.Equal(TaskCategory.Correction, vm.Result.Category);
        Assert.Equal(group.Id, vm.Result.GroupId);
        Assert.Equal(new DateOnly(2026, 12, 24), vm.Result.DueDate);
        Assert.Equal(90, vm.Result.EstimatedMinutes);
    }

    [Fact]
    public void Save_MitUngueltigemDatum_SetztFehler()
    {
        var vm = new AddEditWorkTaskDialogViewModel(null, [])
        {
            Title = "T",
            DueDateText = "nicht-ein-datum",
        };

        vm.SaveCommand.Execute(null);

        Assert.Null(vm.Result);
        Assert.NotEmpty(vm.DueDateError);
    }

    [Fact]
    public void Save_BestehendeAufgabe_BehaeltIdUndStatus()
    {
        var source = new WorkTask { Title = "Alt", Status = WorkTaskStatus.InProgress };
        var vm = new AddEditWorkTaskDialogViewModel(source, []) { Title = "Neu" };

        vm.SaveCommand.Execute(null);

        Assert.Equal(source.Id, vm.Result!.Id);
        Assert.Equal(WorkTaskStatus.InProgress, vm.Result.Status);
    }
}