// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
#include "vtkEdgePoints.h"

#include "vtkCell.h"
#include "vtkCellArray.h"
#include "vtkCellData.h"
#include "vtkDataSet.h"
#include "vtkGenericCell.h"
#include "vtkInformation.h"
#include "vtkInformationVector.h"
#include "vtkMergePoints.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkPolyData.h"

VTK_ABI_NAMESPACE_BEGIN
vtkStandardNewMacro(vtkEdgePoints);

// Construct object with contour value of 0.0.
vtkEdgePoints::vtkEdgePoints()
{
  this->Value = 0.0;
  this->Locator = vtkMergePoints::New();
}

vtkEdgePoints::~vtkEdgePoints()
{
  this->Locator->Delete();
  this->Locator = nullptr;
}

//
// General filter: handles arbitrary input.
//
int vtkEdgePoints::RequestData(vtkInformation* vtkNotUsed(request),
  vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  // get the info objects
  vtkInformation* inInfo = inputVector[0]->GetInformationObject(0);
  vtkInformation* outInfo = outputVector->GetInformationObject(0);

  // get the input and output
  vtkDataSet* input = vtkDataSet::SafeDownCast(inInfo->Get(vtkDataObject::DATA_OBJECT()));
  vtkPolyData* output = vtkPolyData::SafeDownCast(outInfo->Get(vtkDataObject::DATA_OBJECT()));

  vtkDataArray* inScalars;
  vtkPoints* newPts;
  vtkCellArray* newVerts;
  vtkIdType cellId, ptId, edgeId, newCellId;
  int above, below, i, numEdges;
  vtkCell* edge;
  double range[2];
  double s0, s1, x0[3], x1[3], x[3], t;
  double e0Scalar, deltaScalar;
  int e0, e1;
  vtkIdType p1, p2;
  vtkIdType pts[1];
  vtkIdType numCells, estimatedSize;
  vtkDataArray* cellScalars;
  vtkPointData *inPd = input->GetPointData(), *outPd = output->GetPointData();
  vtkCellData *inCd = input->GetCellData(), *outCd = output->GetCellData();

  vtkDebugMacro(<< "Generating edge points");

  // Initialize and check input
  //
  if (!(inScalars = input->GetPointData()->GetScalars()))
  {
    vtkErrorMacro(<< "No scalar data to contour");
    return 1;
  }

  input->GetPointData()->GetRange(inScalars->GetName(), range, 0);
  if (this->Value < range[0] || this->Value > range[1])
  {
    vtkWarningMacro(<< "Value lies outside of scalar range");
    return 1;
  }

  numCells = input->GetNumberOfCells();
  estimatedSize = static_cast<vtkIdType>(numCells * .75);
  estimatedSize = estimatedSize / 1024 * 1024; // multiple of 1024
  if (estimatedSize < 1024)
  {
    estimatedSize = 1024;
  }

  newPts = vtkPoints::New();
  newPts->Allocate(estimatedSize, estimatedSize / 2);
  newVerts = vtkCellArray::New();
  newVerts->AllocateEstimate(estimatedSize, 1);
  cellScalars = inScalars->NewInstance();
  cellScalars->SetNumberOfComponents(inScalars->GetNumberOfComponents());
  cellScalars->Allocate(VTK_CELL_SIZE * inScalars->GetNumberOfComponents());

  this->Locator->InitPointInsertion(newPts, input->GetBounds());

  // interpolate data along edge; copy cell data
  outPd->InterpolateAllocate(inPd, 5000, 10000);
  outCd->CopyAllocate(inCd, 5000, 10000);

  // Traverse all edges. Since edges are not explicitly represented, use a
  // trick: traverse all cells and obtain cell edges and then cell edge
  // neighbors. If cell id < all edge neighbors ids, then this edge has not
  // yet been visited and is processed.
  //
  bool abort = false;
  vtkIdType progressInterval = numCells / 20 + 1;
  vtkGenericCell* cell = vtkGenericCell::New();
  for (cellId = 0; cellId < numCells && !abort; cellId++)
  {
    if (!(cellId % progressInterval))
    {
      vtkDebugMacro(<< "Processing #" << cellId);
      this->UpdateProgress(static_cast<double>(cellId) / numCells);
      abort = this->CheckAbort();
    }

    input->GetCell(cellId, cell);
    cellScalars->SetNumberOfTuples(cell->GetNumberOfPoints());
    inScalars->GetTuples(cell->PointIds, cellScalars);

    // loop over cell points to check if cell straddles isosurface value
    for (above = below = 0, ptId = 0; ptId < cell->GetNumberOfPoints(); ptId++)
    {
      if (cellScalars->GetComponent(ptId, 0) >= this->Value)
      {
        above = 1;
      }
      else
      {
        below = 1;
      }
    }

    if (above && below) // contour passes through cell
    {
      if (cell->GetCellDimension() < 2) // only points can be generated
      {
        cell->Contour(this->Value, cellScalars, this->Locator, newVerts, nullptr, nullptr, inPd,
          outPd, inCd, cellId, outCd);
      }

      else //
      {
        numEdges = cell->GetNumberOfEdges();
        for (edgeId = 0; edgeId < numEdges; edgeId++)
        {
          edge = cell->GetEdge(edgeId);
          inScalars->GetTuples(edge->PointIds, cellScalars);

          s0 = cellScalars->GetComponent(0, 0);
          s1 = cellScalars->GetComponent(1, 0);
          if ((s0 < this->Value && s1 >= this->Value) || (s0 >= this->Value && s1 < this->Value))
          {
            // ordering intersection direction avoids numerical problems
            deltaScalar = s1 - s0;
            if (deltaScalar > 0)
            {
              e0 = 0;
              e1 = 1;
              e0Scalar = s0;
            }
            else
            {
              e0 = 1;
              e1 = 0;
              e0Scalar = s1;
              deltaScalar = -deltaScalar;
            }

            t = (this->Value - e0Scalar) / deltaScalar;

            edge->Points->GetPoint(e0, x0);
            edge->Points->GetPoint(e1, x1);

            for (i = 0; i < 3; i++)
            {
              x[i] = x0[i] + t * (x1[i] - x0[i]);
            }
            if (this->Locator->InsertUniquePoint(x, pts[0]))
            {
              newCellId = newVerts->InsertNextCell(1, pts);
              outCd->CopyData(inCd, cellId, newCellId);
              p1 = edge->PointIds->GetId(e0);
              p2 = edge->PointIds->GetId(e1);
              outPd->InterpolateEdge(inPd, pts[0], p1, p2, t);
            } // if point not created before
          }   // if edge straddles contour value
        }     // for each edge
      }       // dimension 2 and higher
    }         // above and below
  }           // for all cells
  cell->Delete();

  vtkDebugMacro(<< "Created: " << newPts->GetNumberOfPoints() << " points");

  // Update ourselves.  Because we don't know up front how many verts we've
  // created, take care to reclaim memory.
  //
  output->SetPoints(newPts);
  newPts->Delete();

  output->SetVerts(newVerts);
  newVerts->Delete();

  this->Locator->Initialize(); // free up any extra memory
  output->Squeeze();

  cellScalars->Delete();

  return 1;
}

int vtkEdgePoints::FillInputPortInformation(int, vtkInformation* info)
{
  info->Set(vtkAlgorithm::INPUT_REQUIRED_DATA_TYPE(), "vtkDataSet");
  return 1;
}

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

  os << indent << "Contour Value: " << this->Value << "\n";
}
VTK_ABI_NAMESPACE_END
