using System;
using System.Collections;
using System.Collections.Generic;
using System.Threading;
using Cysharp.Threading.Tasks;
using UnityEngine;
using UnityEngine.UIElements;
// ReSharper disable MemberCanBeProtected.Global
// ReSharper disable ClassWithVirtualMembersNeverInherited.Global
// ReSharper disable UnusedMember.Global

namespace BITKit.UX
{
	public class UIToolKitPanel : MonoBehaviour,IUXPanel
	{
		public UIToolKitPanel()
		{
			Index = GetType().FullName;
		}
		[Header(Constant.Header.Components)]
		[SerializeField] protected UIDocument document;
		[Header(Constant.Header.Settings)]
		[SerializeField] private bool isAnimate;
		[SerializeField] private bool allowCursor;
		[SerializeField] private bool allowInput;
		[SerializeField] private bool autoEntry;
		
		[Header(Constant.Header.Settings)]
		[SerializeField] private Optional<float> entryDuration;
		[SerializeField] private Optional<float> exitDuration;
		
		protected readonly InputActionGroup inputActionGroup = new()
		{
			allowGlobalActivation = false
		};
		public bool IsAnimate => isAnimate;
		public bool IsValid => cancellationToken.IsCancellationRequested is false;
		public string Index { get; private set; }
		public bool AllowCursor => allowCursor;
		public bool AllowInput => allowInput;
		protected  CancellationToken cancellationToken { get; private set; }
		protected float TargetOpacity { get; private set; }
		protected virtual VisualElement background => document.rootVisualElement;
		protected float CurrentOpacity
		{
			get => background?.GetOpacity() ?? _currentOpacity;
			set
			{
				_currentOpacity = value;
				background?.SetOpacity(value);
			}
		}
		private float _currentOpacity;
		protected virtual void Awake()
		{
			cancellationToken = gameObject.GetCancellationTokenOnDestroy();
			Index= typeof(UIToolKitPanel) == GetType() ? gameObject.name : GetType().Name;
			document.rootVisualElement.SetActive(false);
			background?.SetOpacity(0);
		}
		protected virtual void Start()
		{
			if(IsValid && autoEntry)
				UXService.Entry(this);
		}
		public bool IsEntered { get; set; }
		public void Entry()
		{
			UXService.Entry(this);
		}

		protected virtual void OnEnable()=>UXService.Register(this);
		protected virtual void OnDisable()=>UXService.UnRegister(this);
        void IEntryElement.Entry()
        {
	        CurrentOpacity = 0;
	        TargetOpacity = 1;
			OnEntryOrExit(true);
			document.rootVisualElement.SetActive(true);
			OnEntry?.Invoke();
		}
        async UniTask IEntryElement.EntryAsync()
        {
	        if (entryDuration.Allow is false) return;
	        while (CurrentOpacity < 1 && TargetOpacity is 1)
	        {
		        await UniTask.NextFrame(cancellationToken);
	        }
        }
        void IEntryElement.Entered()
        {
	        inputActionGroup.allowInput.AddElement(this);
        }

        void IEntryElement.Exit()
		{
			if (IsValid is false) return;
			TargetOpacity = 0;
			OnEntryOrExit(false);
			inputActionGroup.allowInput.RemoveElement(this);
		}
		async UniTask IEntryElement.ExitAsync()
		{
			if (exitDuration.Allow is false) return;
			while (CurrentOpacity > 0 && TargetOpacity is 0)
			{
				await UniTask.NextFrame(cancellationToken);
			}
			OnExit?.Invoke();
		}

        void IEntryElement.Exited()
		{
			document.rootVisualElement.SetActive(false);
		}

		public event Action OnEntry;
		public event Action OnExit;

		protected virtual void OnEntryOrExit(bool isEntry)
		{
		}
		public virtual void OnUpdate(float deltaTime)
		{
			var duration = 1f;
			if (TargetOpacity is 1)
			{
				if (entryDuration.Allow is false)
				{
					CurrentOpacity = TargetOpacity;
					return;
				}
				duration = entryDuration.Value;
			}
			else
			{
				if (exitDuration.Allow is false)
				{
					CurrentOpacity = TargetOpacity;
					return;
				}
				duration = exitDuration.Value;
			}
			CurrentOpacity = Mathf.MoveTowards(CurrentOpacity,TargetOpacity,1f/duration * Time.deltaTime);
		}
	}

}