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

  Program:   ParaView
  Module:    vtkPVCacheKeeper.h

  Copyright (c) Kitware, Inc.
  All rights reserved.
  See Copyright.txt or http://www.paraview.org/HTML/Copyright.html 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   vtkPVCacheKeeper
 * @brief   manages data cache for flip book animations.
 *
 * vtkPVCacheKeeper manages data cache for flip book animations.
 * When caching is disabled, this simply acts as a pass through filter.
 * When caching is enabled, is the current time step has been previously cached
 * then this filter shuts the update request, otherwise propagates the update
 * and then cache the result for later use.  The current time step is set using
 * SetCacheTime().
 * @sa
 * vtkPVCacheKeeperPipeline
*/

#ifndef vtkPVCacheKeeper_h
#define vtkPVCacheKeeper_h

#include "vtkDataObjectAlgorithm.h"
#include "vtkPVClientServerCoreRenderingModule.h" //needed for exports

class vtkCacheSizeKeeper;

class VTKPVCLIENTSERVERCORERENDERING_EXPORT vtkPVCacheKeeper : public vtkDataObjectAlgorithm
{
public:
  static vtkPVCacheKeeper* New();
  vtkTypeMacro(vtkPVCacheKeeper, vtkDataObjectAlgorithm);
  void PrintSelf(ostream& os, vtkIndent indent) VTK_OVERRIDE;

  /**
   * Methods for saving, clearing and updating flip books.
   * This removes all saved cache.
   */
  virtual void RemoveAllCaches();

  //@{
  /**
   * Set/Get the current cache time.
   */
  vtkSetMacro(CacheTime, double);
  vtkGetMacro(CacheTime, double);
  //@}

  /**
   * Returns if the given \c cacheTime is available in the cache.
   * Does not cause any updates.
   */
  virtual bool IsCached(double cacheTime);
  virtual bool IsCached() { return this->IsCached(this->CacheTime); }

  //@{
  /**
   * Get/Set if caching is enabled. Default is true.
   */
  vtkSetMacro(CachingEnabled, bool);
  vtkGetMacro(CachingEnabled, bool);
  vtkBooleanMacro(CachingEnabled, bool);
  //@}

  //@{
  /**
   * These methods are used for testing. Using this global state we can add
   * checks to ensure that cache was used or not used for a particular sequence
   * of actions.
   */
  static void ClearCacheStateFlags();
  static int GetCacheHits();
  static int GetCacheMisses();
  static int GetCacheSkips();
  static int GetCacheClears();
  //@}

protected:
  vtkPVCacheKeeper();
  ~vtkPVCacheKeeper() override;

  //@{
  /**
   * Get/Set the cache size keeper. The cacher
   * reports its cache size to this keeper, if any.
   */
  void SetCacheSizeKeeper(vtkCacheSizeKeeper*);
  vtkGetObjectMacro(CacheSizeKeeper, vtkCacheSizeKeeper);
  //@}

  int RequestDataObject(vtkInformation* request, vtkInformationVector** inputVector,
    vtkInformationVector* outputVector) VTK_OVERRIDE;
  int RequestData(vtkInformation* request, vtkInformationVector** inputVector,
    vtkInformationVector* outputVector) VTK_OVERRIDE;
  vtkExecutive* CreateDefaultExecutive() VTK_OVERRIDE;

  /**
   * Called to save the data in cache. Returns true if data is saved otherwise
   * false.
   */
  virtual bool SaveData(vtkDataObject*);

  bool CachingEnabled;
  double CacheTime;
  vtkCacheSizeKeeper* CacheSizeKeeper;

private:
  vtkPVCacheKeeper(const vtkPVCacheKeeper&) = delete;
  void operator=(const vtkPVCacheKeeper&) = delete;

  class vtkCacheMap;
  vtkCacheMap* Cache;

  static int CacheHit;
  static int CacheMiss;
  static int CacheSkips;
  static int CacheClears;
};

#endif
