// Copyright (c) 2017 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#ifndef _Graphic3d_FrameStats_HeaderFile
#define _Graphic3d_FrameStats_HeaderFile

#include <Graphic3d_FrameStatsData.hxx>
#include <Graphic3d_RenderingParams.hxx>
#include <Standard_Type.hxx>
#include <Standard_Transient.hxx>
#include <TColStd_IndexedDataMapOfStringString.hxx>

class Graphic3d_CView;

//! Class storing the frame statistics.
class Graphic3d_FrameStats : public Standard_Transient
{
  DEFINE_STANDARD_RTTIEXT(Graphic3d_FrameStats, Standard_Transient)
public:

  //! Default constructor.
  Standard_EXPORT Graphic3d_FrameStats();

  //! Destructor.
  Standard_EXPORT virtual ~Graphic3d_FrameStats();

  //! Returns interval in seconds for updating meters across several frames; 1 second by default.
  Standard_Real UpdateInterval() const { return myUpdateInterval; }

  //! Sets interval in seconds for updating values.
  void SetUpdateInterval (Standard_Real theInterval) { myUpdateInterval = theInterval; }

  //! Prefer longer lines over more greater of lines.
  Standard_Boolean IsLongLineFormat() const { return myIsLongLineFormat; }

  //! Set if format should prefer longer lines over greater number of lines.
  void SetLongLineFormat (Standard_Boolean theValue) { myIsLongLineFormat = theValue; }

  //! Frame redraw started.
  Standard_EXPORT virtual void FrameStart (const Handle(Graphic3d_CView)& theView,
                                           bool theIsImmediateOnly);

  //! Frame redraw finished.
  Standard_EXPORT virtual void FrameEnd (const Handle(Graphic3d_CView)& theView,
                                         bool theIsImmediateOnly);

public:

  //! Returns formatted string.
  Standard_EXPORT virtual TCollection_AsciiString FormatStats (Graphic3d_RenderingParams::PerfCounters theFlags) const;

  //! Fill in the dictionary with formatted statistic info.
  Standard_EXPORT virtual void FormatStats (TColStd_IndexedDataMapOfStringString&   theDict,
                                            Graphic3d_RenderingParams::PerfCounters theFlags) const;

  //! Returns duration of the last frame in seconds.
  Standard_Real FrameDuration() const { return myFrameDuration; }

  //! Returns FPS (frames per seconds, elapsed time).
  //! This number indicates an actual frame rate averaged for several frames within UpdateInterval() duration,
  //! basing on a real elapsed time between updates.
  Standard_Real FrameRate() const { return LastDataFrame().FrameRate(); }

  //! Returns CPU FPS (frames per seconds, CPU time).
  //! This number indicates a PREDICTED frame rate,
  //! basing on CPU elapsed time between updates and NOT real elapsed time (which might include periods of CPU inactivity).
  //! Number is expected to be greater then actual frame rate returned by FrameRate().
  //! Values significantly greater actual frame rate indicate that rendering is limited by GPU performance (CPU is stalled in-between),
  //! while values around actual frame rate indicate rendering being limited by CPU performance (GPU is stalled in-between).
  Standard_Real FrameRateCpu() const { return LastDataFrame().FrameRateCpu(); }

  //! Returns value of specified counter, cached between stats updates.
  //! Should NOT be called between ::FrameStart() and ::FrameEnd() calls.
  Standard_Size CounterValue (Graphic3d_FrameStatsCounter theCounter) const { return LastDataFrame()[theCounter]; }

  //! Returns value of specified timer for modification, should be called between ::FrameStart() and ::FrameEnd() calls.
  //! Should NOT be called between ::FrameStart() and ::FrameEnd() calls.
  Standard_Real TimerValue (Graphic3d_FrameStatsTimer theTimer) const { return LastDataFrame()[theTimer]; }

  //! Returns TRUE if some Layers have been culled.
  Standard_Boolean HasCulledLayers() const { return LastDataFrame()[Graphic3d_FrameStatsCounter_NbLayersNotCulled] != LastDataFrame()[Graphic3d_FrameStatsCounter_NbLayers]; }

  //! Returns TRUE if some structures have been culled.
  Standard_Boolean HasCulledStructs() const { return LastDataFrame()[Graphic3d_FrameStatsCounter_NbStructsNotCulled] != LastDataFrame()[Graphic3d_FrameStatsCounter_NbStructs]; }

  //! Returns last data frame, cached between stats updates.
  //! Should NOT be called between ::FrameStart() and ::FrameEnd() calls.
  const Graphic3d_FrameStatsData& LastDataFrame() const { return myCounters.Value (myLastFrameIndex); }

  //! Returns last data frame index.
  Standard_Integer LastDataFrameIndex() const { return myLastFrameIndex; }

  //! Returns data frames.
  const NCollection_Array1<Graphic3d_FrameStatsData>& DataFrames() const { return myCounters; }

  //! Returns data frames.
  NCollection_Array1<Graphic3d_FrameStatsData>& ChangeDataFrames() { return myCounters; }

public:

  //! Returns value of specified counter for modification, should be called between ::FrameStart() and ::FrameEnd() calls.
  Standard_Size& ChangeCounter (Graphic3d_FrameStatsCounter theCounter) { return ActiveDataFrame()[theCounter]; }

  //! Returns value of specified timer for modification, should be called between ::FrameStart() and ::FrameEnd() calls.
  Standard_Real& ChangeTimer (Graphic3d_FrameStatsTimer theTimer) { return ActiveDataFrame()[theTimer]; }

  //! Returns currently filling data frame for modification, should be called between ::FrameStart() and ::FrameEnd() calls.
  Graphic3d_FrameStatsDataTmp& ActiveDataFrame() { return myCountersTmp; }

protected:

  //! Method to collect statistics from the View; called by FrameEnd().
  virtual void updateStatistics (const Handle(Graphic3d_CView)& theView,
                                 bool theIsImmediateOnly) = 0;

protected:

  OSD_Timer        myFpsTimer;                //!< timer for FPS measurements
  Standard_Real    myFrameStartTime;          //!< time at the beginning of frame redraw
  Standard_Real    myFrameDuration;           //!< frame duration
  Standard_Real    myUpdateInterval;          //!< interval to update meters
  Standard_Size    myFpsFrameCount;           //!< FPS counter (within short measurement time slice)
  NCollection_Array1<Graphic3d_FrameStatsData> myCounters; //!< data frames history
  Graphic3d_FrameStatsDataTmp myCountersTmp;  //!< data frame values filled to be filled between FrameStart() and FrameEnd() calls
  Graphic3d_FrameStatsData    myCountersMax;  //!< data frame values with absolute maximum values in the history
  Standard_Integer myLastFrameIndex;          //!< last data frame index
  Standard_Boolean myIsLongLineFormat;        //!< prefer longer lines over greater number of lines

};

#endif // _Graphic3d_FrameStats_HeaderFile