using Engine.Core;

namespace Engine.Integration.SDL3;

public class Sdl3Camera2D : Behaviour, ICamera2D, IFirstFrameUpdate, ILastFrameUpdate, IPreDraw
{
    public Event<Sdl3Camera2D> OnViewMatrixChanged { get; } = new();
    public Event<Sdl3Camera2D> OnProjectionMatrixChanged { get; } = new();
    public Event<Sdl3Camera2D> OnViewportChanged { get; } = new();
    public Event<Sdl3Camera2D> OnZoomChanged { get; } = new();

    private IWindow window = null!;
    public ITransform2D Transform { get; private set; } = null!;

    public Matrix4x4 ProjectionMatrix
    {
        get;
        private set
        {
            if (field == value)
                return;

            field = value;
            OnProjectionMatrixChanged.Invoke(this);
        }
    } = Matrix4x4.Identity;

    public Matrix4x4 ViewMatrix
    {
        get;
        private set
        {
            if (field == value)
                return;

            field = value;
            OnViewMatrixChanged.Invoke(this);
        }
    } = Matrix4x4.Identity;

    public float Zoom
    {
        get;
        set
        {
            float newValue = Math.Max(0.1f, value);

            if (field == newValue)
                return;

            field = newValue;
            OnZoomChanged.Invoke(this);
        }
    } = 1f;

    // TODO This causes delay since OnPreDraw calls assuming this is called in in Update 
    public Vector2D ScreenToWorldPosition(Vector2D screenPosition)
    {
        Vector2D worldPosition = Vector2D.Transform(screenPosition, Transform);
        return worldPosition;
    }

    public Vector2D WorldToScreenPosition(Vector2D worldPosition)
    {
        Vector2D screenPosition = Vector2D.Transform(worldPosition, Transform);
        return screenPosition;
    }

    public void LastActiveFrame() => Transform = null!;
    public void FirstActiveFrame()
    {
        window = BehaviourController.UniverseObject.Universe.FindRequiredBehaviour<IWindow>();
        Transform = BehaviourController.GetRequiredBehaviour<ITransform2D>();
    }

    public void PreDraw()
    {
        ProjectionMatrix = Matrix4x4.CreateOrthographicViewCentered(window.Size.X, window.Size.Y);

        ViewMatrix = Matrix4x4.Identity
            .ApplyScale(Transform.Scale.X.Max(Transform.Scale.Y))
            .ApplyScale(Zoom)
            .ApplyRotationZ(-Transform.Rotation * Math.DegreeToRadian)
            .ApplyTranslation(new Vector3D(-Transform.Position.X, -Transform.Position.Y, 0f));
    }
}