HandDriverUPM/ThirdParty/NaughtyAttributes/Editor/PropertyValidators/ValidateInputPropertyValidator.cs

using UnityEditor;
using System.Reflection;
using System;

namespace NaughtyAttributes.Editor
{
	public class ValidateInputPropertyValidator : PropertyValidatorBase
	{
		private ValidateInputAttribute _cachedValidateInputAttribute;
		
		public override void ValidateProperty(SerializedProperty property)
		{
			if (_cachedValidateInputAttribute == null)
				_cachedValidateInputAttribute = PropertyUtility.GetAttribute<ValidateInputAttribute>(property);
			
			ValidateInputAttribute validateInputAttribute = _cachedValidateInputAttribute;
			object target = PropertyUtility.GetTargetObjectWithProperty(property);

			MethodInfo validationCallback = ReflectionUtility.GetMethod(target, validateInputAttribute.CallbackName);

			if (validationCallback != null &&
				validationCallback.ReturnType == typeof(bool))
			{
				ParameterInfo[] callbackParameters = validationCallback.GetParameters();

				if (callbackParameters.Length == 0) {
					if (!(bool)validationCallback.Invoke(target, null))
					{
						if (string.IsNullOrEmpty(validateInputAttribute.Message))
						{
							NaughtyEditorGUI.HelpBox_Layout(
								property.name + " is not valid", MessageType.Error, context: property.serializedObject.targetObject);
						}
						else
						{
							NaughtyEditorGUI.HelpBox_Layout(
								validateInputAttribute.Message, MessageType.Error, context: property.serializedObject.targetObject);
						}
					}
				}
				else if (callbackParameters.Length == 1)
				{
					FieldInfo fieldInfo = ReflectionUtility.GetField(target, property.name);
					Type fieldType = fieldInfo.FieldType;
					Type parameterType = callbackParameters[0].ParameterType;

					if (fieldType == parameterType)
					{
						if (!(bool)validationCallback.Invoke(target, new object[] { fieldInfo.GetValue(target) }))
						{
							if (string.IsNullOrEmpty(validateInputAttribute.Message))
							{
								NaughtyEditorGUI.HelpBox_Layout(
									property.name + " is not valid", MessageType.Error, context: property.serializedObject.targetObject);
							}
							else
							{
								NaughtyEditorGUI.HelpBox_Layout(
									validateInputAttribute.Message, MessageType.Error, context: property.serializedObject.targetObject);
							}
						}
					}
					else
					{
						string warning = "The field type is not the same as the callback's parameter type";
						NaughtyEditorGUI.HelpBox_Layout(warning, MessageType.Warning, context: property.serializedObject.targetObject);
					}
				}
				else
				{
					string warning =
						validateInputAttribute.GetType().Name +
						" needs a callback with boolean return type and an optional single parameter of the same type as the field";

					NaughtyEditorGUI.HelpBox_Layout(warning, MessageType.Warning, context: property.serializedObject.targetObject);
				}
			}
		}
	}
}