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

namespace BITKit.UX
{
    public class UXToolTips:IDisposable
    {
        private readonly IUXService _uxService;
        private readonly IMainTicker _ticker;

        public UXToolTips(IUXService uxService, IMainTicker ticker)
        {
            _uxService = uxService;
            _ticker = ticker;
            _ticker.Add(OnTick);
        }
        private VisualElement _rootVisualElement;
        private Label _label;

        public void Dispose()
        {
            _ticker.Remove(OnTick);
        }
        private void OnTick(float obj)
        {
            if (_label is null && _uxService.Root is not null)
            {
                _rootVisualElement=_uxService.Root as VisualElement;

                _label = _rootVisualElement.Create<Label>();
            
                _label.AddToClassList("bitkit-tool-tips");

                _label.style.position = Position.Absolute;
            
       
            }
            if(_label is null || _rootVisualElement is null)return;
            var tooltip = CurrentToolTip(_rootVisualElement.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;
                _label.BringToFront();
            }
            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 = Mouse.current.position.ReadValue();
            screenPosition.y = Screen.height - screenPosition.y;

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