Net.Like.Xue.Tokyo/Packages-Local/Com.Project.B.Unity/UX/UXIndicator.cs

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Threading;
using BITKit;
using BITKit.Tween;
using BITKit.UX;
using Cysharp.Threading.Tasks;
using Net.Project.B.Damage;
using Project.B.Entities;
using Unity.Mathematics;
using UnityEngine;
using UnityEngine.UIElements;

namespace Net.Project.B.UX
{
    public class UXIndicator<TPanel> : UIToolkitSubPanel<TPanel> , IDisposable, IUXIndicator where TPanel : IUXPanel
    {
        private struct IndicatorData
        {
            public int Initiator;
            public VisualElement VisualElement;
            public Vector3 Position;
            public CancellationTokenSource CancellationTokenSource;
        }
        
        private readonly IMainTicker _mainTicker;
        private readonly IDamageService _damageService;
        private readonly IPlayerFactory _playerFactory;

        private readonly ConcurrentDictionary<int,IndicatorData> _indicators = new(); 
        
        [UXBindPath("indicator-container")]
        private VisualElement _indicatorContainer;
        private VisualTreeAsset _template;

        private readonly Transform _cameraTransform;
        
        public UXIndicator(IServiceProvider serviceProvider, IDamageService damageService, IPlayerFactory playerFactory, IMainTicker mainTicker) : base(serviceProvider)
        {
            _damageService = damageService;
            _playerFactory = playerFactory;
            _mainTicker = mainTicker;

            _damageService.OnDamaged += OnDamaged;
            
            _mainTicker.Add(OnMainTick);

            _cameraTransform = Camera.main!.transform;
        }

        private void OnMainTick(float obj)
        {
            foreach (var indicatorData in _indicators.Values)
            {
                UpdateIndicator(indicatorData);
            }
        }

        private async void OnDamaged(IDamageReport obj)
        {
            if (_playerFactory.Entities.ContainsKey(obj.Target) is false || obj.Target == obj.Initiator) return;

  

            if (_indicators.TryGetValue(obj.Initiator, out var indicatorData))
            {
                indicatorData.Position = obj.ContactPosition;
                indicatorData.CancellationTokenSource.Cancel();
                indicatorData.CancellationTokenSource = new CancellationTokenSource();
            }
            else
            {
                indicatorData = new IndicatorData()
                {
                    Initiator = obj.Initiator,
                    VisualElement = _indicatorContainer.Create(_template),
                    Position = obj.ContactPosition,
                    CancellationTokenSource = new(),
                };
            }

            _indicators[obj.Initiator] = indicatorData;

            try
            {
                await BITween.CreateSequence()
                        .Append(UniTask.Delay(1000))
                        .Append(BITween.Lerp(indicatorData.VisualElement.SetOpacity, 1f, 0f, 1f, math.lerp,
                            indicatorData.CancellationTokenSource.Token))
                        .Play()
                    ;

                _indicators.TryRemove(obj.Initiator, out _);
                indicatorData.VisualElement.RemoveFromHierarchy();
            }
            catch (OperationCanceledException)
            {

            }
        }


        private void UpdateIndicator(IndicatorData indicatorData){
            
            var rhs = indicatorData.Position - _cameraTransform.position;

            var forward =Vector3.ProjectOnPlane( _cameraTransform.forward,Vector3.up);
            //Convert angle into screen space
            rhs.y = indicatorData.Position.y;
            rhs.Normalize();
            //Get the angle between two positions.
            var angle = Vector3.Angle(rhs, forward);
            //Calculate the perpendicular of both vectors
            //More information about this calculation: https://unity3d.com/es/learn/tutorials/modules/beginner/scripting/vector-maths-dot-cross-products?playlist=17117
            var perpendicular = Vector3.Cross(forward, rhs);
            //Calculate magnitude between two vectors
            var dot = -Vector3.Dot(perpendicular, Vector3.up);
            //get the horizontal angle in direction of target / sender.
            angle = AngleCircumference(dot, angle);
            //Apply the horizontal rotation to the indicator.
			
            indicatorData.VisualElement.transform.rotation = Quaternion.Euler(new(0,0,-angle));

            return;

            float AngleCircumference(float dot, float angle)
            {
                const float circumference = 360f;
                var ac = angle - 10;
                if (dot < 0)
                {
                    ac = circumference - angle;
                }
                return ac;
            }
        }

        protected override async UniTask OnInitiatedAsync()
        {
            await base.OnInitiatedAsync();
            _template = _indicatorContainer.Q<TemplateContainer>().templateSource;
            _indicatorContainer.Clear();
        }

        public void Dispose()
        {
            foreach (var indicatorData in _indicators.Values)
            {
                indicatorData.CancellationTokenSource.Cancel();
            }
            _mainTicker.Remove(OnMainTick);
            _damageService.OnDamaged -= OnDamaged;
        }
    }
}