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

public class ReorderableListContent : MonoBehaviour
{
    private List<Transform> _cachedChildren;
    private List<ReorderableListElement> _cachedListElement;
    private ReorderableListElement _ele;
    private ReorderableList _extList;
    private RectTransform _rect;

    public void OnTransformChildrenChanged()
    {
        StartCoroutine(RefreshChildren());
    }

    public void Init(ReorderableList extList)
    {
        _extList = extList;
        _rect = GetComponent<RectTransform>();
        _cachedChildren = new List<Transform>();
        _cachedListElement = new List<ReorderableListElement>();

        StartCoroutine(RefreshChildren());
    }

    private IEnumerator RefreshChildren()
    {
        //Handle new chilren
        for (int i = 0; i < _rect.childCount; i++)
        {
            if (_cachedChildren.Contains(_rect.GetChild(i)))
                continue;

            //Get or Create ReorderableListElement
            _ele = _rect.GetChild(i).gameObject.GetComponent<ReorderableListElement>() ??
                   _rect.GetChild(i).gameObject.AddComponent<ReorderableListElement>();
            _ele.Init(_extList);

            _cachedChildren.Add(_rect.GetChild(i));
            _cachedListElement.Add(_ele);
        }

        //HACK a little hack, if I don't wait one frame I don't have the right deleted children
        yield return 0;

        //Remove deleted child
        for (int i = _cachedChildren.Count - 1; i >= 0; i--)
        {
            if (_cachedChildren[i] == null)
            {
                _cachedChildren.RemoveAt(i);
                _cachedListElement.RemoveAt(i);
            }
        }
    }
}