[Player] Add AI Pathfinding on a 2D grid to the player character

Assets/External/AstarPathfindingProject/PackageTools/Editor/EnumFlagDrawer.cs

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+using System;
+using System.Reflection;
+using UnityEditor;
+using UnityEngine;
+
+namespace Pathfinding {
+	[CustomPropertyDrawer(typeof(EnumFlagAttribute))]
+	public class EnumFlagDrawer : PropertyDrawer {
+		public override void OnGUI (Rect position, SerializedProperty property, GUIContent label) {
+			Enum targetEnum = GetBaseProperty<Enum>(property);
+
+			EditorGUI.BeginProperty(position, label, property);
+			EditorGUI.BeginChangeCheck();
+#if UNITY_2017_3_OR_NEWER
+			Enum enumNew = EditorGUI.EnumFlagsField(position, label, targetEnum);
+#else
+			Enum enumNew = EditorGUI.EnumMaskField(position, label, targetEnum);
+#endif
+			if (EditorGUI.EndChangeCheck() || !property.hasMultipleDifferentValues) {
+				property.intValue = (int)Convert.ChangeType(enumNew, targetEnum.GetType());
+			}
+			EditorGUI.EndProperty();
+		}
+
+		static T GetBaseProperty<T>(SerializedProperty prop) {
+			// Separate the steps it takes to get to this property
+			string[] separatedPaths = prop.propertyPath.Split('.');
+
+			// Go down to the root of this serialized property
+			System.Object reflectionTarget = prop.serializedObject.targetObject as object;
+			// Walk down the path to get the target object
+			foreach (var path in separatedPaths) {
+				FieldInfo fieldInfo = reflectionTarget.GetType().GetField(path, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
+				reflectionTarget = fieldInfo.GetValue(reflectionTarget);
+			}
+			return (T)reflectionTarget;
+		}
+	}
+}