BITFALL/Assets/BITKit/Unity/Scripts/Events/UnityEvent.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEditor.UIElements;
#if UNITY_EDITOR
using Cysharp.Threading.Tasks;
using UnityEditor;
#endif
using UnityEngine;
using UnityEngine.UIElements;
using Object = UnityEngine.Object;

namespace BITKit.Events
{
	[Serializable]
	public class UnityEventData
	{
		public Object Target;
		public string MethodName;
	}
	[Serializable]
	public class UnityEvent
	{
		public List<UnityEventData> Targets = new List<UnityEventData>();

		public void Invoke(params object[] objects)
		{
			foreach (var x in Targets)
			{
				x.Target.GetType().GetMethod(x.MethodName)?.Invoke(x.Target,objects);
			}
		}
	}
	#if UNITY_EDITOR
	[CustomPropertyDrawer(typeof(UnityEvent))]
	public class UnityEventDataPropertyDrawer:PropertyDrawer
	{
		private VisualElement root;

		private UnityEvent agent;

		private SerializedProperty _property;
		
		public override VisualElement CreatePropertyGUI(SerializedProperty property)
		{
			_property = property;
            agent = property.Get<UnityEvent>();
			
            root = new VisualElement
			{
				style =
				{
					paddingLeft = 10,
					paddingTop = 10,
					paddingRight = 10,
					paddingBottom = 10,
				}
			};
            
            root.styleSheets.Add(BITEditorUtils.InspectorStyleSheet);

            Update();
            
			return root;
		}

		private void Update()
		{
			root.Clear();

			var targets = _property.FindPropertyRelative(nameof(UnityEvent.Targets));

			_property.serializedObject.Update();

			var label = root.Create<Label>();

			label.text = _property.displayName;
			
			var flex = root.Create<VisualElement>();
			
			flex.style.flexDirection = FlexDirection.Row;
			
			var  containers = new[] { flex.Create<VisualElement>(), flex.Create<VisualElement>(),flex.Create<VisualElement>() };

			containers[1].style.flexGrow = 1;
			
			for (var i = 0; i < targets.arraySize; i++)
			{
				var x = agent.Targets[i];
				
				var objectField = containers[0].Create<ObjectField>();
				var field = containers[1].Create<DropdownField>();
				var removeButton = containers[2].Create<Button>();

				
				var data = targets.GetArrayElementAtIndex(i);
				var target = data.FindPropertyRelative(nameof(UnityEventData.Target));
				
				objectField.BindProperty(target);

				if (x.Target is not null)
				{
					field.choices = x.Target.GetType().GetMethods().Select(x => x.Name).ToList();
				}
				
				field.value = x.MethodName;
				field.RegisterValueChangedCallback(changeEvent =>
				{
					x.MethodName = changeEvent.newValue;
				});
				
				
				field.style.flexGrow = 1;

				removeButton.text = "X";
				removeButton.clicked+=()=>{
					agent.Targets.Remove(x);
					Update();
				};
			}
			
			var addButton = root.Create<Button>();
			
			addButton.text = "Add";
			
			addButton.clicked += () =>
			{
				agent.Targets.Add(new());
				Update();
			};

			var invokeButton = root.Create<Button>();
			invokeButton.text = "Invoke";
			invokeButton.clicked +=()=> agent.Invoke();
		}
	}
#endif
}