using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using BITKit.UX;
using BITKit.SubSystems;
using UnityEngine.UIElements;
using Cysharp.Threading.Tasks;
using System.Threading.Tasks;
using System.Threading;
namespace BITKit.Mark
{
    public class MarkSystemUIToolkit : MonoBehaviour
    {
        public UXElement element;
        [SerializeField,SerializeReference, SubclassSelector] private References className;
        [SerializeField, SerializeReference, SubclassSelector]
        private IMarkSystem markSystem;
        Dictionary<string, Label> dictionary = new();
        IPanel panel;
        CancellationToken cancellationToken;
        void Awake()
        {
            cancellationToken = gameObject.GetCancellationTokenOnDestroy();
        }
        void Start()
        {
            panel = element.GetVisualElement().panel;
            if (markSystem is not null)
            {
                markSystem.OnAdd += OnAdd;
                markSystem.OnUpdate += OnUpdate;
                markSystem.OnRemove += OnRemove;
            }
        }
        void OnDestroy()
        {
            if (markSystem is not null)
            {
                markSystem.OnAdd -= OnAdd;
                markSystem.OnUpdate -= OnUpdate;
                markSystem.OnRemove -= OnRemove;
            }
        }
        void OnAdd(IMarkObject markObject)
        {
            GetOrCreate(markObject.GetID());
        }
        async void OnRemove(IMarkObject markObject)
        {
            try
            {
                await UniTask.SwitchToMainThread(cancellationToken);
                if (dictionary.TryGetValue(markObject.GetID(), out var label))
                {
                    element.GetVisualElement().Remove(label);
                    dictionary.Remove(markObject.GetID());
                }
            }
            catch (System.Exception e)
            {
                if (e is not OperationCanceledException)
                    throw;
            }

        }
        async void OnUpdate(IMarkObject markObject)
        {
            var cameraTrans = Camera.main.transform;
            try
            {
                await UniTask.SwitchToMainThread();
                var active = markObject.GetAcitve();
                var label = GetOrCreate(markObject.GetID());
                if (active)
                {
                    var pos = RuntimePanelUtils
                                .CameraTransformWorldToPanel(panel, markObject.GetPostion(), Camera.main);
                    pos.x = (pos.x - label.layout.width / 2);

                    Rect elementRect = new()
                    {
                        position = pos,
                        size = label.layout.size,
                    };
                    label.text = markObject.GetDisplay();
                    label.transform.position = pos;
                    if (Vector3.Dot(cameraTrans.forward, markObject.GetPostion() - cameraTrans.position) > 0)
                    {
                        label.SetActive(true);
                    }
                    else
                    {
                        label.SetActive(false);
                    }
                }
                else
                {
                    label.SetActive(false);
                }
            }
            catch (OperationCanceledException)
            {

            }
            catch (System.Exception)
            {
                throw;
            }

        }
        Label GetOrCreate(string id)
        {
            if (dictionary.TryGetValue(id, out var label))
            {

            }
            else
            {
                label = new();
                label.AddToClassList(className);
                label.style.position = Position.Absolute;
                dictionary.Add(id, label);
                element.GetVisualElement().Add(label);
            }
            return label;
        }
    }
}