/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkViewNode.h

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
/**
 * @class   vtkViewNode
 * @brief   a node within a VTK scene graph
 *
 * This is the superclass for all nodes within a VTK scene graph. It
 * contains the API for a node. It supports the essential operations such
 * as graph creation, state storage and traversal. Child classes adapt this
 * to VTK's major rendering classes. Grandchild classes adapt those to
 * for APIs of different rendering libraries.
 */

#ifndef vtkViewNode_h
#define vtkViewNode_h

#include "vtkObject.h"
#include "vtkRenderingSceneGraphModule.h" // For export macro
#include "vtkWeakPointer.h"               //avoid ref loop to parent

class vtkCollection;
class vtkViewNodeFactory;
class vtkViewNodeCollection;

class VTKRENDERINGSCENEGRAPH_EXPORT vtkViewNode : public vtkObject
{
public:
  vtkTypeMacro(vtkViewNode, vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  //@{
  /**
   * This is the VTK class that this node stands in for.
   */
  vtkGetObjectMacro(Renderable, vtkObject);
  //@}

  /**
   * Builds myself.
   */
  virtual void Build(bool /* prepass */) {}

  /**
   * Ensures that my state agrees with my Renderable's.
   */
  virtual void Synchronize(bool /* prepass */) {}

  /**
   * Makes calls to make self visible.
   */
  virtual void Render(bool /*prepass*/) {}

  /**
   * Clear any cached data.
   */
  virtual void Invalidate(bool /*prepass*/) {}

  //@{
  /**
   * Access the node that owns this one.
   */
  virtual void SetParent(vtkViewNode*);
  virtual vtkViewNode* GetParent();
  //@}

  //@{
  /**
   * Access nodes that this one owns.
   */
  virtual void SetChildren(vtkViewNodeCollection*);
  vtkGetObjectMacro(Children, vtkViewNodeCollection);
  //@}

  //@{
  /**
   * A factory that creates particular subclasses for different
   * rendering back ends.
   */
  virtual void SetMyFactory(vtkViewNodeFactory*);
  vtkGetObjectMacro(MyFactory, vtkViewNodeFactory);
  //@}

  /**
   * Returns the view node that corresponding to the provided object
   * Will return NULL if a match is not found in self or descendents
   */
  vtkViewNode* GetViewNodeFor(vtkObject*);

  /**
   * Find the first parent/grandparent of the desired type
   */
  vtkViewNode* GetFirstAncestorOfType(const char* type);

  /**
   * Find the first child of the desired type
   */
  vtkViewNode* GetFirstChildOfType(const char* type);

  /**
   * Allow explicit setting of the renderable for a
   * view node.
   */
  virtual void SetRenderable(vtkObject*);

  // if you want to traverse your children in a specific order
  // or way override this method
  virtual void Traverse(int operation);

  virtual void TraverseAllPasses();

  /**
   * Allows smart caching
   */
  vtkMTimeType RenderTime;

  /**
   * internal mechanics of graph traversal and actions
   */
  enum operation_type
  {
    noop,
    build,
    synchronize,
    render,
    invalidate
  };

protected:
  vtkViewNode();
  ~vtkViewNode() override;

  static const char* operation_type_strings[];

  void Apply(int operation, bool prepass);

  //@{
  /**
   * convenience method to add node or nodes
   * if missing from our current list
   */
  void AddMissingNode(vtkObject* obj);
  void AddMissingNodes(vtkCollection* col);
  //@}

  //@{
  /**
   * Called first before adding missing nodes.
   * Keeps track of the nodes that should be in the collection
   */
  void PrepareNodes();
  vtkCollection* PreparedNodes;
  //@}

  /**
   * Called after PrepareNodes and AddMissingNodes
   * removes any extra leftover nodes
   */
  void RemoveUnusedNodes();

  /**
   * Create the correct ViewNode subclass for the passed in object.
   */
  virtual vtkViewNode* CreateViewNode(vtkObject* obj);

  vtkObject* Renderable;
  vtkWeakPointer<vtkViewNode> Parent;
  vtkViewNodeCollection* Children;
  vtkViewNodeFactory* MyFactory;

  friend class vtkViewNodeFactory;

private:
  vtkViewNode(const vtkViewNode&) = delete;
  void operator=(const vtkViewNode&) = delete;
};

#endif