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

Assets/External/AstarPathfindingProject/TurnBased/SingleNodeBlocker.cs

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+using UnityEngine;
+
+namespace Pathfinding {
+	/// <summary>
+	/// Blocks single nodes in a graph.
+	///
+	/// This is useful in turn based games where you want
+	/// units to avoid all other units while pathfinding
+	/// but not be blocked by itself.
+	///
+	/// Note: This cannot be used together with any movement script
+	/// as the nodes are not blocked in the normal way.
+	/// See: TurnBasedAI for example usage
+	///
+	/// See: BlockManager
+	/// See: turnbased (view in online documentation for working links)
+	/// </summary>
+	[HelpURL("http://arongranberg.com/astar/docs/class_pathfinding_1_1_single_node_blocker.php")]
+	public class SingleNodeBlocker : VersionedMonoBehaviour {
+		public GraphNode lastBlocked { get; private set; }
+		public BlockManager manager;
+
+		/// <summary>
+		/// Block node closest to the position of this object.
+		///
+		/// Will unblock the last node that was reserved (if any)
+		/// </summary>
+		public void BlockAtCurrentPosition () {
+			BlockAt(transform.position);
+		}
+
+		/// <summary>
+		/// Block node closest to the specified position.
+		///
+		/// Will unblock the last node that was reserved (if any)
+		/// </summary>
+		public void BlockAt (Vector3 position) {
+			Unblock();
+			var node = AstarPath.active.GetNearest(position, NNConstraint.None).node;
+			if (node != null) {
+				Block(node);
+			}
+		}
+
+		/// <summary>
+		/// Block specified node.
+		///
+		/// Will unblock the last node that was reserved (if any)
+		/// </summary>
+		public void Block (GraphNode node) {
+			if (node == null)
+				throw new System.ArgumentNullException("node");
+
+			manager.InternalBlock(node, this);
+			lastBlocked = node;
+		}
+
+		/// <summary>Unblock the last node that was blocked (if any)</summary>
+		public void Unblock () {
+			if (lastBlocked == null || lastBlocked.Destroyed) {
+				lastBlocked = null;
+				return;
+			}
+
+			manager.InternalUnblock(lastBlocked, this);
+			lastBlocked = null;
+		}
+	}
+}