/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file aiNode.h
 * @author Deepak, John, Navin
 * @date 2009-11-18
 */

#ifndef AINODE_H
#define AINODE_H

#include "aiGlobals.h"

/**
 * This class is used to assign the nodes on the mesh.  It holds all the data
 * necessary to compute A* algorithm.  It also maintains a lot of vital
 * information such as the neighbor nodes of each node and also its position
 * on the mesh.  Note: The Mesh Generator which is a standalone tool makes use
 * of this class to generate the nodes on the mesh.
 */
class EXPCL_PANDAAI AINode {
public:
  // This variable specifies the node status whether open, close or neutral.
  // open = belongs to _open_list.  close = belongs to _closed_list.  neutral
  // = unexamined node.
  enum Status {
    ST_open,
    ST_close,
    ST_neutral
  };
  Status _status;

  // This variable specifies whether the node is an obtacle or not.  Used for
  // dynamic obstacle addition to the environment.  obstacle = false
  // navigational = true
  bool _type;

  // The score is used to compute the traversal expense to nodes when using
  // A*. _score = _cost + heuristic
  int _score;
  int _cost;
  int _heuristic;

  // Used to trace back the path after it is generated using A*.
  AINode *_prv_node;

  // Position of the node in the 2d grid.
  int _grid_x, _grid_y;

  // Position of the node in 3D space.
  LVecBase3 _position;

  // Dimensions of each face  cell on the mesh.  Height is given in case of
  // expansion to a 3d mesh.  Currently not used.
  float _width, _length ,_height;
  AINode *_neighbours[8]; // anti-clockwise from top left corner.

  // The _next pointer is used for traversal during mesh generation from the
  // model.  Note: The data in this member is discarded when mesh data is
  // written into navmesh.csv file.
  AINode *_next;

PUBLISHED:
  explicit AINode(int grid_x, int grid_y, LVecBase3 pos, float w, float l, float h);
  ~AINode();

  bool contains(float x, float y);
};

#endif