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

  Program:   Visualization Toolkit
  Module:    vtkXMLUnstructuredGridReader.cxx

  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.

=========================================================================*/
#include "vtkXMLUnstructuredGridReader.h"

#include "vtkCellArray.h"
#include "vtkIdTypeArray.h"
#include "vtkObjectFactory.h"
#include "vtkUnsignedCharArray.h"
#include "vtkUnstructuredGrid.h"
#include "vtkXMLDataElement.h"
#include "vtkInformation.h"
#include "vtkStreamingDemandDrivenPipeline.h"

#include <cassert>

vtkStandardNewMacro(vtkXMLUnstructuredGridReader);

//----------------------------------------------------------------------------
vtkXMLUnstructuredGridReader::vtkXMLUnstructuredGridReader()
{
  this->CellElements = nullptr;
  this->NumberOfCells = nullptr;
  this->CellsTimeStep = -1;
  this->CellsOffset   = static_cast<unsigned long>(-1); // almost invalid state
}

//----------------------------------------------------------------------------
vtkXMLUnstructuredGridReader::~vtkXMLUnstructuredGridReader()
{
  if(this->NumberOfPieces)
  {
    this->DestroyPieces();
  }
}

//----------------------------------------------------------------------------
void vtkXMLUnstructuredGridReader::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os, indent);
}

//----------------------------------------------------------------------------
vtkUnstructuredGrid* vtkXMLUnstructuredGridReader::GetOutput()
{
  return this->GetOutput(0);
}

//----------------------------------------------------------------------------
vtkUnstructuredGrid* vtkXMLUnstructuredGridReader::GetOutput(int idx)
{
  return vtkUnstructuredGrid::SafeDownCast( this->GetOutputDataObject(idx) );
}

//----------------------------------------------------------------------------
const char* vtkXMLUnstructuredGridReader::GetDataSetName()
{
  return "UnstructuredGrid";
}

//----------------------------------------------------------------------------
void vtkXMLUnstructuredGridReader::GetOutputUpdateExtent(int& piece,
                                                         int& numberOfPieces,
                                                         int& ghostLevel)
{
  vtkInformation* outInfo = this->GetCurrentOutputInformation();
  piece = outInfo->Get(
      vtkStreamingDemandDrivenPipeline::UPDATE_PIECE_NUMBER());
  numberOfPieces = outInfo->Get(
      vtkStreamingDemandDrivenPipeline::UPDATE_NUMBER_OF_PIECES());
  ghostLevel = outInfo->Get(
      vtkStreamingDemandDrivenPipeline::UPDATE_NUMBER_OF_GHOST_LEVELS());
}

//----------------------------------------------------------------------------
void vtkXMLUnstructuredGridReader::SetupOutputTotals()
{
  this->Superclass::SetupOutputTotals();
  // Find the total size of the output.
  int i;
  this->TotalNumberOfCells = 0;
  for(i=this->StartPiece; i < this->EndPiece; ++i)
  {
    this->TotalNumberOfCells += this->NumberOfCells[i];
  }

  // Data reading will start at the beginning of the output.
  this->StartCell = 0;
}

//----------------------------------------------------------------------------
void vtkXMLUnstructuredGridReader::SetupPieces(int numPieces)
{
  this->Superclass::SetupPieces(numPieces);
  this->NumberOfCells = new vtkIdType[numPieces];
  this->CellElements = new vtkXMLDataElement*[numPieces];
  for(int i=0;i < numPieces; ++i)
  {
    this->CellElements[i] = nullptr;
  }
}

//----------------------------------------------------------------------------
void vtkXMLUnstructuredGridReader::DestroyPieces()
{
  delete [] this->CellElements;
  delete [] this->NumberOfCells;
  this->Superclass::DestroyPieces();
}

//----------------------------------------------------------------------------
vtkIdType vtkXMLUnstructuredGridReader::GetNumberOfCellsInPiece(int piece)
{
  return this->NumberOfCells[piece];
}

//----------------------------------------------------------------------------
void vtkXMLUnstructuredGridReader::SetupOutputData()
{
  this->Superclass::SetupOutputData();

  vtkUnstructuredGrid* output = vtkUnstructuredGrid::SafeDownCast(
      this->GetCurrentOutput());

  // Setup the output's cell arrays.
  vtkUnsignedCharArray* cellTypes = vtkUnsignedCharArray::New();
  cellTypes->SetNumberOfTuples(this->GetNumberOfCells());
  vtkCellArray* outCells = vtkCellArray::New();

  vtkIdTypeArray* locations = vtkIdTypeArray::New();
  locations->SetNumberOfTuples(this->GetNumberOfCells());

  output->SetCells(cellTypes, locations, outCells);

  locations->Delete();
  outCells->Delete();
  cellTypes->Delete();
}

//----------------------------------------------------------------------------
int vtkXMLUnstructuredGridReader::ReadPiece(vtkXMLDataElement* ePiece)
{
  if(!this->Superclass::ReadPiece(ePiece))
  {
    return 0;
  }
  int i;

  if(!ePiece->GetScalarAttribute("NumberOfCells",
                                 this->NumberOfCells[this->Piece]))
  {
    vtkErrorMacro("Piece " << this->Piece
                  << " is missing its NumberOfCells attribute.");
    this->NumberOfCells[this->Piece] = 0;
    return 0;
  }

  // Find the Cells element in the piece.
  this->CellElements[this->Piece] = nullptr;
  for(i=0; i < ePiece->GetNumberOfNestedElements(); ++i)
  {
    vtkXMLDataElement* eNested = ePiece->GetNestedElement(i);
    if((strcmp(eNested->GetName(), "Cells") == 0)
       && (eNested->GetNumberOfNestedElements() > 0))
    {
      this->CellElements[this->Piece] = eNested;
    }
  }

  if(!this->CellElements[this->Piece])
  {
    vtkErrorMacro("A piece is missing its Cells element.");
    return 0;
  }

  return 1;
}

//----------------------------------------------------------------------------
void vtkXMLUnstructuredGridReader::SetupNextPiece()
{
  this->Superclass::SetupNextPiece();
  this->StartCell += this->NumberOfCells[this->Piece];
}


//----------------------------------------------------------------------------
int vtkXMLUnstructuredGridReader::ReadPieceData()
{
  // The amount of data read by the superclass's ReadPieceData comes
  // from point/cell data and point specifications (we read cell
  // specifications here).
  vtkIdType superclassPieceSize =
    ((this->NumberOfPointArrays+1)*this->GetNumberOfPointsInPiece(this->Piece)+
     this->NumberOfCellArrays*this->GetNumberOfCellsInPiece(this->Piece));

  // Total amount of data in this piece comes from cell/face data arrays.
  // Three of them are for standard vtkUnstructuredGrid cell specification:
  // connectivities, offsets and types. Two optional arrays are for face
  // specification of polyhedron cells: faces and face offsets.
  // Note: We don't know exactly the array size of cell connectivities and
  // faces until we actually read the file. The following progress computation
  // assumes that each array cost the same time to read.
  vtkIdType totalPieceSize =
    superclassPieceSize + 5*this->GetNumberOfCellsInPiece(this->Piece);
  if(totalPieceSize == 0)
  {
    totalPieceSize = 1;
  }

  // Split the progress range based on the approximate fraction of
  // data that will be read by each step in this method.  The cell
  // specification reads two arrays, and then the cell types array is
  // one more.
  float progressRange[2] = {0,0};
  this->GetProgressRange(progressRange);
  float fractions[5] =
    {
      0,
      float(superclassPieceSize) / totalPieceSize,
      ((float(superclassPieceSize) +
        2*this->GetNumberOfCellsInPiece(this->Piece)) / totalPieceSize),
      ((float(superclassPieceSize) +
        3*this->GetNumberOfCellsInPiece(this->Piece)) / totalPieceSize),
      1
    };

  // Set the range of progress for the superclass.
  this->SetProgressRange(progressRange, 0, fractions);

  // Let the superclass read its data.
  if(!this->Superclass::ReadPieceData())
  {
    return 0;
  }

  vtkUnstructuredGrid* output = vtkUnstructuredGrid::SafeDownCast(
      this->GetCurrentOutput());

  // Set the range of progress for the cell specifications.
  this->SetProgressRange(progressRange, 1, fractions);

  // Read the Cells.
  vtkXMLDataElement* eCells = this->CellElements[this->Piece];
  if(!eCells)
  {
    vtkErrorMacro("Cannot find cell arrays in piece " << this->Piece);
    return 0;
  }

//  int needToRead = this->CellsNeedToReadTimeStep(eNested,
//    this->CellsTimeStep, this->CellsOffset);
//  if( needToRead )
  {
    // Read the array.
    if(!this->ReadCellArray(this->NumberOfCells[this->Piece],
                            this->TotalNumberOfCells,
                            eCells,
                            output->GetCells()))
    {
      return 0;
    }
  }

  // Construct the cell locations.
  vtkIdTypeArray* locations = output->GetCellLocationsArray();
  vtkIdType* locs = locations->GetPointer(this->StartCell);
  vtkIdTypeArray* cellArrayData = output->GetCells()->GetData();
  vtkIdType startLoc = 0;
  if (this->StartCell > 0)
  {
    // this set the startLoc to point to the location in the cellArray where the
    // cell for this piece will start writing.

    // Id for last written cell:
    vtkIdType lastWrittenCell = this->StartCell - 1;
    vtkIdType locationOfLastWrittenCell = locations->GetValue(lastWrittenCell);
    startLoc = locationOfLastWrittenCell + 1 +
      cellArrayData->GetValue(locationOfLastWrittenCell);
    // startLoc = location-of-last-written-cell + 1 (for put the count for items in the cell)
    //            + (number of items in the cell).
  }
  vtkIdType* begin = output->GetCells()->GetData()->GetPointer(startLoc);
  vtkIdType* cur = begin;
  vtkIdType i;
  for(i=0; i < this->NumberOfCells[this->Piece]; ++i)
  {
    locs[i] = startLoc + cur - begin;
    cur += *cur + 1;
  }

  // Set the range of progress for the cell types.
  this->SetProgressRange(progressRange, 2, fractions);

  // Read the corresponding cell types.
  vtkIdType numberOfCells = this->NumberOfCells[this->Piece];
  if (numberOfCells > 0)
  {
    vtkXMLDataElement* eTypes = this->FindDataArrayWithName(eCells, "types");
    if(!eTypes)
    {
      vtkErrorMacro("Cannot read cell types from " << eCells->GetName()
                    << " in piece " << this->Piece
                    << " because the \"types\" array could not be found.");
      return 0;
    }
    vtkAbstractArray* ac2 = this->CreateArray(eTypes);
    vtkDataArray* c2 = vtkArrayDownCast<vtkDataArray>(ac2);
    if(!c2 || (c2->GetNumberOfComponents() != 1))
    {
      vtkErrorMacro("Cannot read cell types from " << eCells->GetName()
                    << " in piece " << this->Piece
                    << " because the \"types\" array could not be created"
                    << " with one component.");
      if (ac2) { ac2->Delete(); }
      return 0;
    }
    c2->SetNumberOfTuples(numberOfCells);
    if(!this->ReadArrayValues(eTypes, 0, c2, 0, numberOfCells))
    {
      vtkErrorMacro("Cannot read cell types from " << eCells->GetName()
                    << " in piece " << this->Piece
                    << " because the \"types\" array is not long enough.");
      return 0;
    }
    vtkUnsignedCharArray* cellTypes = this->ConvertToUnsignedCharArray(c2);
    if(!cellTypes)
    {
      vtkErrorMacro("Cannot read cell types from " << eCells->GetName()
                    << " in piece " << this->Piece
                    << " because the \"types\" array could not be converted"
                    << " to a vtkUnsignedCharArray.");
      return 0;
    }

    // Copy the cell type data.
    memcpy(output->GetCellTypesArray()->GetPointer(this->StartCell),
           cellTypes->GetPointer(0), numberOfCells);

    cellTypes->Delete();
  }

  // Set the range of progress for the faces.
  this->SetProgressRange(progressRange, 3, fractions);

  //
  // Read face array. Used for polyhedron mesh support. First need to
  // check if faces and faceoffsets arrays are available in this piece.
  if (!this->FindDataArrayWithName(eCells, "faces") ||
      !this->FindDataArrayWithName(eCells, "faceoffsets"))
  {
    if (output->GetFaces())
    {
      // This piece doesn't have any polyhedron but other pieces that
      // we've already processed do so we need to add in face information
      // for cells that don't have that by marking -1.
      for(vtkIdType c=0;c<numberOfCells;c++)
      {
        output->GetFaceLocations()->InsertNextValue(-1);
      }
    }
    return 1;
  }

  // By default vtkUnstructuredGrid does not contain face information, which is
  // only used by polyhedron cells. If so far no polyhedron cells have been
  // added, the pointers to the arrays will be nullptr. In this case, we need to
  // initialize the arrays and assign values to the previous non-polyhedron cells.
  if (!output->GetFaces() || !output->GetFaceLocations())
  {
    output->InitializeFacesRepresentation(this->StartCell);
  }

  // Read face arrays.
  if(!this->ReadFaceArray(this->NumberOfCells[this->Piece],
                          eCells,
                          output->GetFaces(),
                          output->GetFaceLocations()))
  {
    return 0;
  }

  return 1;
}

//----------------------------------------------------------------------------
int vtkXMLUnstructuredGridReader::ReadArrayForCells(vtkXMLDataElement* da,
                                                    vtkAbstractArray* outArray)
{
  vtkIdType startCell = this->StartCell;
  vtkIdType numCells = this->NumberOfCells[this->Piece];
  vtkIdType components = outArray->GetNumberOfComponents();
  return this->ReadArrayValues(da, startCell*components, outArray,
    0, numCells*components);
}


//----------------------------------------------------------------------------
int vtkXMLUnstructuredGridReader::FillOutputPortInformation(int, vtkInformation *info)
{
  info->Set(vtkDataObject::DATA_TYPE_NAME(), "vtkUnstructuredGrid");
  return 1;
}