using System;
using System.Collections;
using System.Collections.Generic;
using System.Threading;
using Cysharp.Threading.Tasks;
using UnityEngine;
using UnityEngine.Events;

namespace BITKit.UX
{
	public class UXTabContainerEvent : UXElement<TabContainer>
	{
		[Tooltip("基于<see cref=\"TabBar\"/>的Tab切换事件")]
		[SerializeField] private UnityEvent<bool>[] onEntryTab;

		[SerializeField] private UnityEvent[] onEntry;
		[SerializeField] private UnityEvent[] onExit;
		
		private readonly DoubleBuffer<int> tabBuffer = new();
		private CancellationToken _cancellationToken;
		public override void OnAwake()
		{
			base.OnAwake();
			_cancellationToken = gameObject.GetCancellationTokenOnDestroy();
		}

		public override async void OnStart()
		{
			base.OnStart();
			visualElement.OnTabChanged += OnTabChanged;
			foreach (var unityEvent in onEntryTab)
			{
				unityEvent.Invoke(false);
			}

			try
			{
				await UniTask.NextFrame(_cancellationToken);
				OnTabChanged(visualElement.CurrentTab);
			}
			catch(OperationCanceledException){}
		}
		private void OnTabChanged(int obj)
		{
			if(onEntryTab.TryGetElementAt(tabBuffer.Current,out var unityEvent))
			{
				unityEvent.Invoke(false);
			}
			if(onEntryTab.TryGetElementAt(obj, out unityEvent))
			{
				unityEvent.Invoke(true);
			}
			if(onExit.TryGetElementAt(tabBuffer.Current,out var exitEvent))
			{
				exitEvent.Invoke();
			}
			if(onEntry.TryGetElementAt(obj, out var entryEvent))
			{
				entryEvent.Invoke();
			}
			tabBuffer.Release(obj);
		}
	}

}