// Copyright (c) 2021 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 _RWMesh_TriangulationSource_HeaderFile
#define _RWMesh_TriangulationSource_HeaderFile

#include "Poly_Triangulation.hxx"
#include "NCollection_Array1.hxx"

class RWMesh_TriangulationReader;

//! Mesh data wrapper for delayed triangulation loading.
//! Class inherits Poly_Triangulation so that it can be put temporarily into TopoDS_Face within
//! assembly structure.
class RWMesh_TriangulationSource : public Poly_Triangulation
{
  DEFINE_STANDARD_RTTIEXT(RWMesh_TriangulationSource, Poly_Triangulation)
public:
  //! Constructor.
  Standard_EXPORT RWMesh_TriangulationSource();

  //! Destructor.
  Standard_EXPORT ~RWMesh_TriangulationSource() override;

  //! Returns reader allowing to read data from the buffer.
  const occ::handle<RWMesh_TriangulationReader>& Reader() const { return myReader; }

  //! Sets reader allowing to read data from the buffer.
  void SetReader(const occ::handle<RWMesh_TriangulationReader>& theReader) { myReader = theReader; }

  //! Returns number of degenerated triangles collected during data reading.
  //! Used for debug statistic purpose.
  int DegeneratedTriNb() const { return myStatisticOfDegeneratedTriNb; }

  //! Gets access to number of degenerated triangles to collect them during data reading.
  int& ChangeDegeneratedTriNb() { return myStatisticOfDegeneratedTriNb; }

  //! Returns TRUE if triangulation has some geometry.
  bool HasGeometry() const override
  {
    return !myNodes.IsEmpty() && (!myTriangles.IsEmpty() || !myEdges.IsEmpty());
  }

  //! Returns the number of edges for this triangulation.
  int NbEdges() const { return myEdges.Length(); }

  //! Returns edge at the given index.
  //! @param[in] theIndex edge index within [1, NbEdges()] range
  //! @return edge node indices, with each node defined within [1, NbNodes()] range
  int Edge(int theIndex) const { return myEdges.Value(theIndex); }

  //! Sets an edge.
  //! @param[in] theIndex edge index within [1, NbEdges()] range
  //! @param[in] theEdge edge node indices, with each node defined within [1, NbNodes()] range
  void SetEdge(int theIndex, int theEdge) { myEdges.SetValue(theIndex, theEdge); }

public: //! @name late-load deferred data interface
  //! Returns number of nodes for deferred loading.
  //! Note: this is estimated values defined in object header, which might be different from
  //! actually loaded values (due to broken header or extra mesh processing). Always check
  //! triangulation size of actually loaded data in code to avoid out-of-range issues.
  int NbDeferredNodes() const override { return myNbDefNodes; }

  //! Sets number of nodes for deferred loading.
  void SetNbDeferredNodes(const int theNbNodes) { myNbDefNodes = theNbNodes; }

  //! Returns number of triangles for deferred loading.
  //! Note: this is estimated values defined in object header, which might be different from
  //! actually loaded values (due to broken header or extra mesh processing). Always check
  //! triangulation size of actually loaded data in code to avoid out-of-range issues.
  int NbDeferredTriangles() const override { return myNbDefTriangles; }

  //! Sets number of triangles for deferred loading.
  void SetNbDeferredTriangles(const int theNbTris) { myNbDefTriangles = theNbTris; }

  //! Returns an internal array of edges.
  //! Edge()/SetEdge() should be used instead in portable code.
  NCollection_Array1<int>& InternalEdges() { return myEdges; }

  //! Method resizing an internal array of triangles.
  //! @param[in] theNbTriangles  new number of triangles
  //! @param[in] theToCopyOld    copy old triangles into the new array
  Standard_EXPORT void ResizeEdges(int theNbEdges, bool theToCopyOld);

protected:
  //! Loads triangulation data from deferred storage using specified shared input file system.
  Standard_EXPORT bool loadDeferredData(
    const occ::handle<OSD_FileSystem>&     theFileSystem,
    const occ::handle<Poly_Triangulation>& theDestTriangulation) const override;

protected:
  occ::handle<RWMesh_TriangulationReader> myReader;
  NCollection_Array1<int>                 myEdges;
  int                                     myNbDefNodes;
  int                                     myNbDefTriangles;
  mutable int                             myStatisticOfDegeneratedTriNb;
};

#endif // _RWMesh_TriangulationSource_HeaderFile