using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using UnityEngine.UIElements;

namespace BITKit.UX
{
	public class TabContainer : VisualElement
	{
		public new class UxmlTraits : VisualElement.UxmlTraits
		{
			private readonly UxmlIntAttributeDescription m_currentTabAttribute = new ()
			{
				name = "CurrentTab",
				defaultValue = -1
			};
			private readonly UxmlStringAttributeDescription m_customTabPathAttribute = new ()
			{
				name = "CustomTabPath",
			};
			public override void Init(VisualElement ve, IUxmlAttributes bag, CreationContext cc)
			{
				base.Init(ve, bag, cc);
				var tabContainer = (TabContainer)ve;
				tabContainer.CurrentTab = m_currentTabAttribute.GetValueFromBag(bag, cc);
				tabContainer.CustomTabPath = m_customTabPathAttribute.GetValueFromBag(bag, cc);
				tabContainer.pickingMode = PickingMode.Ignore;
				tabContainer._container.pickingMode = PickingMode.Ignore;
			}
		}
		public new class UxmlFactory : UxmlFactory<TabContainer, UxmlTraits> { }
		public TabContainer()
		{
			_internalTabBar = new TabBar();
			_container = new VisualElement
			{
				name = UXConstant.ContextContainer,
				style =
				{
					flexGrow = 1
				}
			};
			hierarchy.Add(_internalTabBar);
			hierarchy.Add(_container);
			RegisterCallback<AttachToPanelEvent>(OnAttachToPanel);
			RegisterCallback<DetachFromPanelEvent>(OnDetachFromPanel);
			_internalTabBar.OnTabChanged += EntryTab;
			pickingMode = PickingMode.Ignore;
			_container.pickingMode = PickingMode.Ignore;
		}
		public override VisualElement contentContainer => _container;
		public event Action<int> OnTabChanged; 
		private int currentTab=-1;

		public int CurrentTab
		{
			get => currentTab;
			set
			{
				currentTab = value;
				EntryTab(currentTab);
			}
		}
		
		private string _customTabPath;
		public string CustomTabPath
		{
			get => _customTabPath;
			set
			{
				_customTabPath = value;
				if (_externalTabBar is not null)
				{
					_externalTabBar.OnTabChanged -= EntryTab;
				}
				if (panel?.visualTree != null)
				{
					_externalTabBar = panel.visualTree.Q<TabBar>(value);
					if (_externalTabBar is not null)
					{
						_externalTabBar.OnTabChanged += EntryTab;
					}
				}
				_internalTabBar.SetActive(_externalTabBar is null);
			}
		}
		private readonly VisualElement _container;
		private readonly TabBar _internalTabBar;
		private TabBar _externalTabBar;
		
		private void OnDetachFromPanel(DetachFromPanelEvent evt)
		{
			UpdateTabBar();
		}
		private void OnAttachToPanel(AttachToPanelEvent evt)
		{
			UpdateTabBar();
		}
		private void UpdateTabBar()
		{
			CustomTabPath = CustomTabPath;
			CurrentTab = CurrentTab;
			_externalTabBar?.SetValueWithoutNotify(CurrentTab);
			_internalTabBar.SetValueWithoutNotify(CurrentTab);
			_internalTabBar.Tabs = string.Join(",", _container.Children().Select(x => x.name));
		}
		private void OnShowTab(bool value)
		{
			_internalTabBar.style.display = value ? DisplayStyle.Flex : DisplayStyle.None;
		}
		public void EntryTab(int index)
		{
			foreach (var x in _container.Children())
			{
				x.SetActive(false);
			}
			if(_container.Children().TryGet(index,out var element))
				element.SetActive(true);
			OnTabChanged?.Invoke(index);
		}
	}
}