using Engine.Core;
using Engine.Systems.Graphics;

namespace Pong.Behaviours;

public class DrawableCircle : Behaviour2D, IDrawableTriangle, IPreDraw
{
    private const float CIRCLE_SEGMENT_COUNT = 32f;

    private readonly Circle circle = new();
    private Circle worldCircle = new();

    public ColorRGBA Color { get; set; } = new ColorRGBA(255, 255, 255);

    public void PreDraw() => UpdateWorldCircle();

    public void Draw(ITriangleBatch triangleBatch)
    {
        for (int i = 0; i < CIRCLE_SEGMENT_COUNT; i++)
        {
            float iPi1 = i / CIRCLE_SEGMENT_COUNT * 2f * Math.Pi;
            float iPi2 = (i + 1f).Mod(CIRCLE_SEGMENT_COUNT) / CIRCLE_SEGMENT_COUNT * 2f * Math.Pi;

            Vector2D firstVertex = new Vector2D(Math.Sin(iPi1), Math.Cos(iPi1)) * worldCircle.Radius;
            Vector2D secondVertex = new Vector2D(Math.Sin(iPi2), Math.Cos(iPi2)) * worldCircle.Radius;
            triangleBatch.Draw(new(worldCircle.Center, worldCircle.Center + firstVertex, worldCircle.Center + secondVertex), Color);
        }
    }

    protected void UpdateWorldCircle() => worldCircle = circle.Transform(Transform);

    public DrawableCircle(Circle circle) { this.circle = circle; }
    public DrawableCircle(Circle circle, ColorRGBA color) { this.circle = circle; Color = color; }
}