using Avalonia;
using Omika.App.Controls;
using Xunit;

namespace Omika.Tests.Controls;

/// <summary>
/// Tests de la machine à états du tracé de signature (mono-pointeur). La logique
/// est extraite du contrôle visuel <see cref="SignaturePad"/> pour être testable
/// sans plateforme de rendu Avalonia (environnement headless).
/// </summary>
public sealed class SignatureStrokeTrackerTests
{
    [Fact]
    public void TryBeginStroke_PremierPointeur_ActiveLeTrait()
    {
        var tracker = new SignatureStrokeTracker();

        bool started = tracker.TryBeginStroke(pointerId: 1, new Point(5, 5));

        Assert.True(started);
        Assert.True(tracker.IsDrawing);
        Assert.Equal(1, tracker.ActivePointerId);
        Assert.Single(tracker.Points);
        Assert.Equal(new Point(5, 5), tracker.Points[0]);
    }

    [Fact]
    public void TryBeginStroke_SecondPointeurPendantTrait_EstIgnore()
    {
        var tracker = new SignatureStrokeTracker();
        tracker.TryBeginStroke(pointerId: 1, new Point(5, 5));

        bool started = tracker.TryBeginStroke(pointerId: 2, new Point(99, 99));

        Assert.False(started);
        Assert.Equal(1, tracker.ActivePointerId);
        Assert.Single(tracker.Points);
        Assert.Equal(new Point(5, 5), tracker.Points[0]);
    }

    [Fact]
    public void TryAddPoint_PointeurActif_AjoutePointEtRetournePrecedent()
    {
        var tracker = new SignatureStrokeTracker();
        tracker.TryBeginStroke(pointerId: 1, new Point(0, 0));

        Point? previous = tracker.TryAddPoint(pointerId: 1, new Point(10, 20));

        Assert.True(previous.HasValue);
        Assert.Equal(new Point(0, 0), previous!.Value);
        Assert.Equal(2, tracker.Points.Count);
        Assert.Equal(new Point(10, 20), tracker.Points[1]);
    }

    [Fact]
    public void TryAddPoint_PointeurNonActif_EstIgnore()
    {
        var tracker = new SignatureStrokeTracker();
        tracker.TryBeginStroke(pointerId: 1, new Point(0, 0));

        Point? previous = tracker.TryAddPoint(pointerId: 2, new Point(99, 99));

        Assert.Null(previous);
        Assert.Single(tracker.Points);
    }

    [Fact]
    public void EndStroke_ReinitialiseEtatComplet()
    {
        var tracker = new SignatureStrokeTracker();
        tracker.TryBeginStroke(pointerId: 1, new Point(0, 0));
        tracker.TryAddPoint(pointerId: 1, new Point(10, 10));

        tracker.EndStroke();

        Assert.False(tracker.IsDrawing);
        Assert.Null(tracker.ActivePointerId);
        Assert.Empty(tracker.Points);
    }

    [Fact]
    public void NouveauTraitApresEndStroke_Fonctionne()
    {
        var tracker = new SignatureStrokeTracker();
        tracker.TryBeginStroke(pointerId: 1, new Point(0, 0));
        tracker.EndStroke();

        bool started = tracker.TryBeginStroke(pointerId: 3, new Point(7, 7));

        Assert.True(started);
        Assert.Equal(3, tracker.ActivePointerId);
        Assert.Single(tracker.Points);
        Assert.Equal(new Point(7, 7), tracker.Points[0]);
    }

    [Fact]
    public void IsActivePointer_MauvaisPointeur_NeTerminePasLeTraitActif()
    {
        var tracker = new SignatureStrokeTracker();
        tracker.TryBeginStroke(pointerId: 1, new Point(0, 0));

        // Le relâchement d'un mauvais PointerId (second doigt) ne doit pas être
        // interprété comme la fin du trait actif.
        Assert.True(tracker.IsActivePointer(1));
        Assert.False(tracker.IsActivePointer(2));
        Assert.True(tracker.IsDrawing);
    }

    [Fact]
    public void TryAddPoint_SansTraitActif_RetourneNull()
    {
        var tracker = new SignatureStrokeTracker();

        Point? previous = tracker.TryAddPoint(pointerId: 1, new Point(10, 10));

        Assert.Null(previous);
        Assert.False(tracker.IsDrawing);
    }
}