using System.Numerics;
using DaggerFramework.Rendering;

namespace DaggerFramework.UI;

/// <summary>
/// A basic container for UI elements. All container's children will update their constraints based on container's sizing and positioning.
/// </summary>
public class Container : UIElement
{
    /// <summary>
    /// Updates the sizes of the container and rearranges its children.
    /// </summary>
    /// <param name="position"></param>
    /// <param name="size"></param>
    public void UpdateRect(Vector2 position, Vector2 size)
    {
        Rect.Position = position;

        UpdateSize(size);
        RearrangeChildren();
    }

    protected void RearrangeChildren()
    {
        int idx = 0;
        foreach (var child in children)
        {
            if (child is Container container)
            {
                container.UpdateRect(Rect.Position, Rect.Size);
            }
            RearrangeChild(idx, child);
            idx++;
        }
    }

    protected virtual void RearrangeChild(int idx, UIElement child) { }

    protected override void OnRender(Renderer renderer)
    {

    }

    private void UpdateSize(Vector2 baseSize)
    {
        if (parent == null)
        {
            Rect.Size = baseSize;
            return;
        }

        if (VerticalSizeFlags == SizeFlags.Fill)
        {
            Rect.Size = new Vector2(Rect.Size.X, baseSize.Y * ExpandRatio.Y);
        }

        if (HorizontalSizeFlags == SizeFlags.Fill)
        {
            Rect.Size = new Vector2(baseSize.X * ExpandRatio.X, Rect.Size.Y);
        }
    }
}