using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.InputSystem;
using UnityEngine.UIElements;

namespace BITKit.UX
{
	public class UXToolTips : MonoBehaviour
	{
		private VisualElement root;
		private Label label;

		private void Start()
		{
			root = GetComponent<UIDocument>().rootVisualElement;
			label = root.Q<Label>();
		}

		private void Update()
		{
			var tooltip = CurrentToolTip(root.panel);
			if (tooltip != "")
			{
				var mouse = Mouse.current;
				if (mouse is null) return;
				var mousePos = mouse.position.ReadValue();
				mousePos.y = Screen.height - mousePos.y;
				var pos =RuntimePanelUtils.ScreenToPanel(label.panel,mousePos);
				pos.x += 24;
				if (pos.x + label.layout.width > label.panel.visualTree.layout.width)
				{
					//pos.x = label.panel.visualTree.layout.width - label.layout.width - label.layout.width;
					pos.x-=label.layout.width+48;
				}
				
				label.visible = true;
				label.text = tooltip;
				label.transform.position = pos;
			}
			else
			{
				label.visible = false;
			}
		}

		private string CurrentToolTip(IPanel panel)
		{
			// https://docs.unity3d.com/2022.2/Documentation/Manual/UIE-faq-event-and-input-system.html

			if (!EventSystem.current.IsPointerOverGameObject()) return "";

			var screenPosition = Input.mousePosition;
			screenPosition.y = Screen.height - screenPosition.y;

			VisualElement ve = panel.Pick(RuntimePanelUtils.ScreenToPanel(panel, screenPosition));
			return ve == null ? "" : ve.tooltip;
		}
	}
}