using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices.Expando;
using System.Security.Cryptography;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;
using XRLib.UI;

namespace Studio
{
    public class HierarchyPanel : PanelBase,IDropHandler
    {
        public ScrollRect scrollrect_hierarchycontent;
        public UI_HierarchyItem prf_hierarchyitem;
        
        internal Action<TwinObject> onClickItem;
        internal Action<TreeItem> onItemDrop;
        internal Action<TreeItem, TreeItem> OnItemDropOnItem;
        
        private Dictionary<TreeItem, UI_HierarchyItem> itemToView = new();
        private Dictionary<UI_HierarchyItem, TreeItem> viewToItem = new();
        HashSet<TreeItem> tempHashSet = new();

        public float tap = 30f;

        public override void AfterAwake()
        {
            prf_hierarchyitem = Resources.Load<UI_HierarchyItem>("Prefabs/UI/PRF_TreeItem");
        }

        public void OnDrop(PointerEventData eventData)
        {
            if (eventData.pointerDrag != null)
            {
                UI_HierarchyItem draggeditem = eventData.pointerDrag.GetComponent<UI_HierarchyItem>();
                if (draggeditem)
                {
                    var item = viewToItem[draggeditem];
                    onItemDrop(item);
                }
            }
        }


        public void AddItem(TreeItem item)
        {
            UI_HierarchyItem itemView = Instantiate(prf_hierarchyitem, scrollrect_hierarchycontent.content);
            item.onExpand += Expand;
            item.onFold += Fold;
            itemView.Set(item);
            itemView.onDestroy += RemoveItem;
            itemView.onClick += OnClickItem;

            UI_DragDrop_ ui_DragDrop = itemView.transform.GetComponent<UI_DragDrop_>();
            ui_DragDrop.OnDropItem += ItemDrop;

            viewToItem.Add(itemView, item);
            itemToView.Add(item, itemView);
        }

        void ItemDrop(UIBase parent, UIBase child)
        {
            if(parent is UI_HierarchyItem parentItem && child is UI_HierarchyItem childItem)
            {
                var pi = viewToItem[parentItem];
                var ci = viewToItem[childItem];
                OnItemDropOnItem(pi, ci);
            }
        }

        void Expand(TreeItem item)
        {
            var rootChildren = item.children;
            for (int i = 0; i < rootChildren.Count; ++i)
            {
                var rootChild = item.children[i];
                tempHashSet.Add(rootChild);

                if (!rootChild.expanded)
                {
                    continue;
                }

                var rootChildItem = rootChild;
                for (int j = 0; j < rootChildItem.children.Count; ++j)
                {
                    var leafChild = rootChildItem.children[j];
                    GetExpandTargets(leafChild);
                }
            }
            foreach (var r in tempHashSet)
            {
                
                itemToView[r].gameObject.SetActive(true);
            }
            tempHashSet.Clear();
        }

        void GetExpandTargets(TreeItem i)
        {
            tempHashSet.Add(i);
            if (!i.expanded)
            {
                return;
            }

            var children = i.children;
            foreach (var item in children)
            {
                tempHashSet.Add(item);
                GetExpandTargets(item);
            }
        }

        void Fold(TreeItem item)
        {
            GetFoldTargets(item);
            foreach (var r in tempHashSet)
            {
                var view = itemToView[r];
                view.SetActive(false);
            }
            tempHashSet.Clear();
        }

        void GetFoldTargets(TreeItem i)
        {
            var children = i.children;
            foreach (var item in children)
            {
                if (itemToView[i].gameObject.activeSelf)
                {
                    tempHashSet.Add(item);
                    GetFoldTargets(item);
                }
            }
        }

        public void UpdateIndex(List<TreeItem> data)
        {
            for(int i = 0; i < data.Count; i++)
            {
                var item = data[i];
                var view = itemToView[item];
                var depth = data[i].depth;
                view.transform.SetSiblingIndex(i);
                var TapRectTransform = view.transform.GetChild(0).GetComponentInChildren<RectTransform>(true);
                TapRectTransform.offsetMin = new Vector2(depth * tap, TapRectTransform.offsetMin.y);

            }
        }

        void OnClickItem(UI_HierarchyItem view)
        {
            var item = viewToItem[view];
            onClickItem?.Invoke(item.ToItem);
        }

        public void RemoveItem(UI_HierarchyItem to)
        {
            itemToView.Remove(viewToItem[to]);
            viewToItem.Remove(to);
        }
    }
}