using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UIElements;

namespace Net.BITKit.UX
{
    public class AdaptiveGrid : VisualElement
    {
        public new class UxmlFactory : UxmlFactory<AdaptiveGrid, UxmlTraits>
        {
        }

        public AdaptiveGrid()
        {
            style.flexDirection = FlexDirection.Row;
            style.flexWrap = Wrap.Wrap;

            RegisterCallback<GeometryChangedEvent>(_ => UpdateLayout());
            RegisterCallback<AttachToPanelEvent>(_ => UpdateLayout());
            RegisterCallback<DetachFromPanelEvent>(_ => UpdateLayout());
        }

        private void UpdateLayout()
        {
            var width = resolvedStyle.width;

            if (childCount == 0 || width <= 0) return;

            var sampleVisualElement = contentContainer[0];

            var max = sampleVisualElement.resolvedStyle.maxWidth.value;
            var min = sampleVisualElement.resolvedStyle.minHeight.value;

            if (max == 0)
            {
                max = sampleVisualElement.resolvedStyle.width;
            }
            if(min == 0)
            {
                min = max * 0.8f;
            }
            
            var count= Mathf.FloorToInt(width / min);
            
            var remainder = width % count;
            var itemWidth = (width - remainder) / count;
            var itemHeight = itemWidth * 0.8f;

            var spacing = (width - itemWidth * count) / (count - 1);
            spacing = spacing < 0 ? 0 : spacing;
            
            for (var i = 0; i < childCount; i++)
            {
                var child =contentContainer[i];
                child.style.width = itemWidth-spacing;
                child.style.height = itemHeight-spacing;

                if (i % count != 0)
                {
                    child.style.marginRight = spacing;
                    child.style.marginBottom = spacing;
                }
            }

        }

    }

}