// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause

#include "vtkHigherOrderQuadrilateral.h"

#include "vtkCellData.h"
#include "vtkDoubleArray.h"
#include "vtkHigherOrderCurve.h"
#include "vtkHigherOrderInterpolation.h"
#include "vtkIdList.h"
#include "vtkMath.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkPoints.h"
#include "vtkQuad.h"
#include "vtkTriangle.h"
#include "vtkVector.h"

#include <array>

VTK_ABI_NAMESPACE_BEGIN
vtkHigherOrderQuadrilateral::vtkHigherOrderQuadrilateral()
{
  this->Approx = nullptr;
  this->Order[0] = this->Order[1] = 1;
  // Deliberately leave this unset. When GetOrder() is called, it will construct
  // the accompanying data arrays used for other calculations.
  this->Order[2] = 0;

  this->Points->SetNumberOfPoints(4);
  this->PointIds->SetNumberOfIds(4);
  for (vtkIdType i = 0; i < 4; i++)
  {
    this->Points->SetPoint(i, 0.0, 0.0, 0.0);
    this->PointIds->SetId(i, -1);
  }
}

vtkHigherOrderQuadrilateral::~vtkHigherOrderQuadrilateral() = default;

void vtkHigherOrderQuadrilateral::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os, indent);
  os << indent << "Order: " << this->GetOrder(0) << "\n";
  if (this->PointParametricCoordinates)
  {
    os << indent
       << "PointParametricCoordinates: " << this->PointParametricCoordinates->GetNumberOfPoints()
       << " entries\n";
  }
  os << indent << "Approx: " << this->Approx << "\n";
}

void vtkHigherOrderQuadrilateral::SetEdgeIdsAndPoints(int edgeId,
  const std::function<void(const vtkIdType&)>& set_number_of_ids_and_points,
  const std::function<void(const vtkIdType&, const vtkIdType&)>& set_ids_and_points)
{
  const int* order = this->GetOrder();
  // Note in calls below: quad has same edges as first 4 of hex
  int oi = vtkHigherOrderInterpolation::GetVaryingParameterOfHexEdge(edgeId);
  vtkVector2i eidx = vtkHigherOrderInterpolation::GetPointIndicesBoundingHexEdge(edgeId);
  vtkIdType npts = order[oi] + 1;
  int sn = 0;

  set_number_of_ids_and_points(npts);
  for (int i = 0; i < 2; ++i, ++sn)
  {
    set_ids_and_points(sn, eidx[i]);
  }
  // Now add edge-interior points in axis order:
  int offset = 4;
  for (int ee = 0; ee < edgeId; ++ee)
  {
    offset += order[ee % 2 == 0 ? 0 : 1] - 1;
  }
  for (int jj = 0; jj < order[oi] - 1; ++jj, ++sn)
  {
    set_ids_and_points(sn, offset + jj);
  }
}

void vtkHigherOrderQuadrilateral::Initialize() {}

int vtkHigherOrderQuadrilateral::CellBoundary(
  int vtkNotUsed(subId), const double pcoords[3], vtkIdList* pts)
{
  double t1 = pcoords[0] - pcoords[1];
  double t2 = 1.0 - pcoords[0] - pcoords[1];

  pts->SetNumberOfIds(2);

  // compare against two lines in parametric space that divide element
  // into four pieces.
  if (t1 >= 0.0 && t2 >= 0.0)
  {
    pts->SetId(0, this->PointIds->GetId(0));
    pts->SetId(1, this->PointIds->GetId(1));
  }

  else if (t1 >= 0.0 && t2 < 0.0)
  {
    pts->SetId(0, this->PointIds->GetId(1));
    pts->SetId(1, this->PointIds->GetId(2));
  }

  else if (t1 < 0.0 && t2 < 0.0)
  {
    pts->SetId(0, this->PointIds->GetId(2));
    pts->SetId(1, this->PointIds->GetId(3));
  }

  else //( t1 < 0.0 && t2 >= 0.0 )
  {
    pts->SetId(0, this->PointIds->GetId(3));
    pts->SetId(1, this->PointIds->GetId(0));
  }

  if (pcoords[0] < 0.0 || pcoords[0] > 1.0 || pcoords[1] < 0.0 || pcoords[1] > 1.0)
  {
    return 0;
  }
  else
  {
    return 1;
  }
}

int vtkHigherOrderQuadrilateral::EvaluatePosition(const double x[3], double closestPoint[3],
  int& subId, double pcoords[3], double& minDist2, double weights[])
{
  int result = 0;

  int dummySubId;
  double linearWeights[4];
  double tmpDist2;
  vtkVector3d params;
  vtkVector3d tmpClosestPt;

  minDist2 = VTK_DOUBLE_MAX;
  vtkIdType nquad = vtkHigherOrderInterpolation::NumberOfIntervals<2>(this->GetOrder());
  for (int subCell = 0; subCell < nquad; ++subCell)
  {
    vtkQuad* approx = this->GetApproximateQuad(subCell, nullptr, nullptr);
    int stat = approx->EvaluatePosition(
      x, tmpClosestPt.GetData(), dummySubId, params.GetData(), tmpDist2, linearWeights);
    if (stat != -1 && tmpDist2 < minDist2)
    {
      result = stat;
      subId = subCell;
      minDist2 = tmpDist2;
      for (int ii = 0; ii < 3; ++ii)
      {
        pcoords[ii] = params[ii]; // We will translate the winning parameter values later.
        if (closestPoint)
        {
          closestPoint[ii] = tmpClosestPt[ii];
        }
      }
    }
  }

  if (result != -1)
  {
    this->TransformApproxToCellParams(subId, pcoords);
    if (closestPoint)
    {
      this->EvaluateLocation(dummySubId, pcoords, closestPoint, weights);
    }
    else
    {
      this->InterpolateFunctions(pcoords, weights);
    }
  }

  return result;
}

void vtkHigherOrderQuadrilateral::EvaluateLocation(
  int& subId, const double pcoords[3], double x[3], double* weights)
{
  subId = 0; // TODO: Should this be -1?
  this->InterpolateFunctions(pcoords, weights);

  // Efficient point access
  const auto pointsArray = vtkDoubleArray::FastDownCast(this->Points->GetData());
  if (!pointsArray)
  {
    vtkErrorMacro(<< "Points should be double type");
    return;
  }
  const double* pts = pointsArray->GetPointer(0);

  const double* p;
  x[0] = x[1] = x[2] = 0.;
  vtkIdType nPoints = this->GetPoints()->GetNumberOfPoints();
  for (vtkIdType idx = 0; idx < nPoints; ++idx)
  {
    p = pts + 3 * idx;
    for (vtkIdType jdx = 0; jdx < 3; ++jdx)
    {
      x[jdx] += p[jdx] * weights[idx];
    }
  }
}

void vtkHigherOrderQuadrilateral::Contour(double value, vtkDataArray* cellScalars,
  vtkIncrementalPointLocator* locator, vtkCellArray* verts, vtkCellArray* lines,
  vtkCellArray* polys, vtkPointData* inPd, vtkPointData* outPd, vtkCellData* inCd, vtkIdType cellId,
  vtkCellData* outCd)
{
  this->PrepareApproxData(
    inPd, inCd, cellId, cellScalars); // writes to this->{CellScalars, ApproxPD, ApproxCD}
  vtkIdType nquad = vtkHigherOrderInterpolation::NumberOfIntervals<2>(this->GetOrder());
  for (int i = 0; i < nquad; ++i)
  {
    vtkQuad* approx =
      this->GetApproximateQuad(i, this->CellScalars.GetPointer(), this->Scalars.GetPointer());
    approx->Contour(value, this->Scalars.GetPointer(), locator, verts, lines, polys, this->ApproxPD,
      outPd, this->ApproxCD, cellId, outCd);
  }
}

void vtkHigherOrderQuadrilateral::Clip(double value, vtkDataArray* cellScalars,
  vtkIncrementalPointLocator* locator, vtkCellArray* polys, vtkPointData* inPd, vtkPointData* outPd,
  vtkCellData* inCd, vtkIdType cellId, vtkCellData* outCd, int insideOut)
{
  this->PrepareApproxData(
    inPd, inCd, cellId, cellScalars); // writes to this->{CellScalars, ApproxPD, ApproxCD}
  vtkIdType nquad = vtkHigherOrderInterpolation::NumberOfIntervals<2>(this->GetOrder());
  for (int i = 0; i < nquad; ++i)
  {
    vtkQuad* approx =
      this->GetApproximateQuad(i, this->CellScalars.GetPointer(), this->Scalars.GetPointer());
    approx->Clip(value, this->Scalars.GetPointer(), locator, polys, this->ApproxPD, outPd,
      this->ApproxCD, cellId, outCd, insideOut);
  }
}

int vtkHigherOrderQuadrilateral::IntersectWithLine(
  const double* p1, const double* p2, double tol, double& t, double* x, double* pcoords, int& subId)
{
  vtkIdType nquad = vtkHigherOrderInterpolation::NumberOfIntervals<2>(this->GetOrder());
  double tFirst = VTK_DOUBLE_MAX;
  bool intersection = false;
  vtkVector3d tmpX;
  vtkVector3d tmpP;
  int tmpId;
  for (int i = 0; i < nquad; ++i)
  {
    vtkQuad* approx = this->GetApproximateQuad(i);
    if (approx->IntersectWithLine(p1, p2, tol, t, tmpX.GetData(), tmpP.GetData(), tmpId))
    {
      // Record the point closest to p1 in the direction of p2 unless there is no other
      // intersection, in which case we will report a point "before" p1 (further from p2 than p1).
      if (!intersection || (t >= 0 && (t < tFirst || tFirst < 0)))
      {
        tFirst = t;
        subId = i;
        for (int ii = 0; ii < 3; ++ii)
        {
          x[ii] = tmpX[ii];
          pcoords[ii] = tmpP[ii]; // Translate this after we're sure it's the closest hit.
        }
      }
      intersection = true;
    }
  }
  if (intersection)
  {
    intersection &= this->TransformApproxToCellParams(subId, pcoords);
    t = tFirst;
  }
  return intersection ? 1 : 0;
}

int vtkHigherOrderQuadrilateral::TriangulateLocalIds(int vtkNotUsed(index), vtkIdList* ptIds)
{
  // The base of the pyramid must be split into two triangles.  There are two
  // ways to do this (across either diagonal).  Pick the shorter diagonal.
  double d1 = vtkMath::Distance2BetweenPoints(this->Points->GetPoint(0), this->Points->GetPoint(2));
  double d2 = vtkMath::Distance2BetweenPoints(this->Points->GetPoint(1), this->Points->GetPoint(3));
  constexpr std::array<vtkIdType, 6> localPtIds1{ 0, 1, 2, 0, 2, 3 };
  constexpr std::array<vtkIdType, 6> localPtIds2{ 0, 1, 3, 1, 2, 3 };

  vtkIdType nquad = vtkHigherOrderInterpolation::NumberOfIntervals<2>(this->GetOrder());
  ptIds->SetNumberOfIds(nquad * 6);
  int i, j, k, corner;
  int count = 0;
  for (int subId = 0; subId < nquad; ++subId)
  {
    if (!this->SubCellCoordinatesFromId(i, j, k, subId))
    {
      vtkErrorMacro("Invalid subId " << subId);
      return 0;
    }
    for (vtkIdType ic : ((d1 <= d2) ? localPtIds1 : localPtIds2))
    {
      corner = this->PointIndexFromIJK(
        i + ((((ic + 1) / 2) % 2) ? 1 : 0), j + (((ic / 2) % 2) ? 1 : 0), 0);
      ptIds->SetId(count, corner);
      count++;
    }
  }
  return 1;
}

void vtkHigherOrderQuadrilateral::Derivatives(
  int vtkNotUsed(subId), const double pcoords[3], const double* values, int dim, double* derivs)
{
  vtkIdType numberOfPoints = this->Points->GetNumberOfPoints();

  double sum[2], p[3];
  std::vector<double> functionDerivs(2 * numberOfPoints);
  double *J[3], J0[3], J1[3], J2[3];
  double *JI[3], JI0[3], JI1[3], JI2[3];

  this->InterpolateDerivs(pcoords, functionDerivs.data());

  // Compute transposed Jacobian and inverse Jacobian
  J[0] = J0;
  J[1] = J1;
  J[2] = J2;
  JI[0] = JI0;
  JI[1] = JI1;
  JI[2] = JI2;
  for (int k = 0; k < 3; k++)
  {
    J0[k] = J1[k] = 0.0;
  }

  for (int i = 0; i < numberOfPoints; i++)
  {
    this->Points->GetPoint(i, p);
    for (int j = 0; j < 2; j++)
    {
      for (int k = 0; k < 3; k++)
      {
        J[j][k] += p[k] * functionDerivs[j + 2 * i];
      }
    }
  }

  // Compute third row vector in transposed Jacobian and normalize it, so that Jacobian determinant
  // stays the same.
  vtkMath::Cross(J0, J1, J2);
  if (vtkMath::Normalize(J2) == 0.0 || !vtkMath::InvertMatrix(J, JI, 3)) // degenerate
  {
    for (int j = 0; j < dim; j++)
    {
      for (int i = 0; i < 3; i++)
      {
        derivs[j * dim + i] = 0.0;
      }
    }
    return;
  }

  // Loop over "dim" derivative values. For each set of values,
  // compute derivatives
  // in local system and then transform into modelling system.
  // First compute derivatives in local x'-y' coordinate system
  for (int j = 0; j < dim; j++)
  {
    sum[0] = sum[1] = 0.0;
    for (int i = 0; i < numberOfPoints; i++) // loop over interp. function derivatives
    {
      sum[0] += functionDerivs[2 * i] * values[dim * i + j];
      sum[1] += functionDerivs[2 * i + 1] * values[dim * i + j];
    }
    //    dBydx = sum[0]*JI[0][0] + sum[1]*JI[0][1];
    //    dBydy = sum[0]*JI[1][0] + sum[1]*JI[1][1];

    // Transform into global system (dot product with global axes)
    derivs[3 * j] = sum[0] * JI[0][0] + sum[1] * JI[0][1];
    derivs[3 * j + 1] = sum[0] * JI[1][0] + sum[1] * JI[1][1];
    derivs[3 * j + 2] = sum[0] * JI[2][0] + sum[1] * JI[2][1];
  }
}

void vtkHigherOrderQuadrilateral::SetParametricCoords()
{
  if (!this->PointParametricCoordinates)
  {
    this->PointParametricCoordinates = vtkSmartPointer<vtkPoints>::New();
    this->PointParametricCoordinates->SetDataTypeToDouble();
  }

  // Ensure Order is up-to-date and check that current point size matches:
  if (static_cast<int>(this->PointParametricCoordinates->GetNumberOfPoints()) != this->GetOrder(2))
  {
    this->PointParametricCoordinates->Initialize();
    vtkHigherOrderInterpolation::AppendQuadrilateralCollocationPoints(
      this->PointParametricCoordinates, this->Order);
  }
}

double* vtkHigherOrderQuadrilateral::GetParametricCoords()
{
  this->SetParametricCoords();

  return vtkDoubleArray::SafeDownCast(this->PointParametricCoordinates->GetData())->GetPointer(0);
}

double vtkHigherOrderQuadrilateral::GetParametricDistance(const double pcoords[3])
{
  double pDist, pDistMax = 0.0;

  for (int ii = 0; ii < 2; ++ii)
  {
    pDist = (pcoords[ii] < 0. ? -pcoords[ii] : (pcoords[ii] > 1. ? pcoords[ii] - 1. : 0.));
    if (pDist > pDistMax)
    {
      pDistMax = pDist;
    }
  }

  // The quadrilateral's 3rd parametric coordinate should always be 0:
  if (pcoords[2] != 0.0 && (pDist = std::abs(pcoords[2])) > pDistMax)
  {
    pDistMax = pDist;
  }

  return pDistMax;
}

/// Return a linear quadrilateral used to approximate a region of the nonlinear quadrilateral.
vtkQuad* vtkHigherOrderQuadrilateral::GetApprox()
{
  if (!this->Approx)
  {
    this->Approx = vtkSmartPointer<vtkQuad>::New();
    this->ApproxPD = vtkSmartPointer<vtkPointData>::New();
    this->ApproxCD = vtkSmartPointer<vtkCellData>::New();
  }
  return this->Approx.GetPointer();
}

/**\brief Prepare point data for use by linear approximating-elements.
 *
 * This copies the point data for the current cell into a new point-data
 * object so that the point ids and scalar ids can match.
 */
void vtkHigherOrderQuadrilateral::PrepareApproxData(
  vtkPointData* pd, vtkCellData* cd, vtkIdType cellId, vtkDataArray* cellScalars)
{
  this->GetApprox(); // Ensure this->Approx{PD,CD} are non-NULL.
  // this->GetOrder(); // Ensure the order has been updated to match this element.
  this->SetOrderFromCellData(cd, this->Points->GetNumberOfPoints(), cellId);
  vtkIdType npts = this->Order[2];
  vtkIdType nele = this->Order[0] * this->Order[1];
  this->ApproxPD->Initialize();
  this->ApproxCD->Initialize();
  this->ApproxPD->CopyAllOn();
  this->ApproxCD->CopyAllOn();
  this->ApproxPD->CopyAllocate(pd, npts);
  this->ApproxCD->CopyAllocate(cd, nele);
  this->CellScalars->SetNumberOfTuples(npts);
  for (int pp = 0; pp < npts; ++pp)
  {
    this->ApproxPD->CopyData(pd, this->PointIds->GetId(pp), pp);
    this->CellScalars->SetValue(pp, cellScalars->GetTuple1(pp));
  }
  for (int ee = 0; ee < nele; ++ee)
  {
    this->ApproxCD->CopyData(cd, cellId, ee);
  }
}

/// A convenience method; see the overloaded variant for more information.
bool vtkHigherOrderQuadrilateral::SubCellCoordinatesFromId(vtkVector3i& ijk, int subId)
{
  return this->SubCellCoordinatesFromId(ijk[0], ijk[1], ijk[2], subId);
}

/**\brief Given an integer specifying an approximating linear quad, compute its IJK
 * coordinate-position in this cell.
 *
 * The \a subId specifies the lower-, left-, front-most vertex of the approximating quad.
 * This sets the ijk coordinates of that point.
 *
 * You must have called this->GetOrder() **before** invoking this method so that the order will be
 * up to date.
 */
bool vtkHigherOrderQuadrilateral::SubCellCoordinatesFromId(int& i, int& j, int& k, int subId)
{
  if (subId < 0)
  {
    return false;
  }

  i = subId % this->Order[0];
  j = (subId / this->Order[0]) % this->Order[1];
  k = 0;
  return i + this->Order[0] * j == subId;
}

/**\brief A convenience function to get a connectivity offset from a control-point tuple.
 *
 * Ensure that you have called GetOrder() before calling this method
 * so that this->Order is up to date. This method does no checking
 * before using it to map connectivity-array offsets.
 */
int vtkHigherOrderQuadrilateral::PointIndexFromIJK(int i, int j, int vtkNotUsed(k))
{
  return vtkHigherOrderQuadrilateral::PointIndexFromIJK(i, j, this->Order);
}

/**\brief Given (i,j,k) coordinates within the HigherOrder quad, return an offset into the local
 * connectivity (PointIds) array.
 *
 * The \a order parameter must point to the start of an array of 2 integers.
 */
int vtkHigherOrderQuadrilateral::PointIndexFromIJK(int i, int j, const int* order)
{
  bool ibdy = (i == 0 || i == order[0]);
  bool jbdy = (j == 0 || j == order[1]);
  // How many boundaries do we lie on at once?
  int nbdy = (ibdy ? 1 : 0) + (jbdy ? 1 : 0);

  if (nbdy == 2) // Vertex DOF
  {              // ijk is a corner node. Return the proper index (somewhere in [0,7]):
    return (i ? (j ? 2 : 1) : (j ? 3 : 0));
  }

  int offset = 4;
  if (nbdy == 1) // Edge DOF
  {
    if (!ibdy)
    { // On i axis
      return (i - 1) + (j ? order[0] - 1 + order[1] - 1 : 0) + offset;
    }
    if (!jbdy)
    { // On j axis
      return (j - 1) + (i ? order[0] - 1 : 2 * (order[0] - 1) + order[1] - 1) + offset;
    }
  }

  offset += 2 * (order[0] - 1 + order[1] - 1);
  // nbdy == 0: Face DOF
  return offset + (i - 1) + (order[0] - 1) * ((j - 1));
}

/**\brief Given the index, \a subCell, of a linear approximating-quad, translate pcoords from that
 * quad into this nonlinear quad.
 *
 * You must call this->GetOrder() **before** invoking this method as it assumes
 * the order is up to date.
 */
bool vtkHigherOrderQuadrilateral::TransformApproxToCellParams(int subCell, double* pcoords)
{
  vtkVector3i ijk;
  if (!this->SubCellCoordinatesFromId(ijk, subCell))
  {
    return false;
  }
  for (int pp = 0; pp < 2; ++pp)
  {
    pcoords[pp] = (pcoords[pp] + ijk[pp]) / this->Order[pp];
  }
  pcoords[2] = 0.;
  return true;
}

/**\brief Set the degree  of the cell, given a vtkDataSet and cellId
 */
void vtkHigherOrderQuadrilateral::SetOrderFromCellData(
  vtkCellData* cell_data, vtkIdType numPts, vtkIdType cell_id)
{
  vtkHigherOrderQuadrilateral::SetOrderFromCellData(cell_data, numPts, cell_id, this->Order);
}

void vtkHigherOrderQuadrilateral::SetOrderFromCellData(
  vtkCellData* cell_data, vtkIdType numPts, vtkIdType cell_id, int* order)
{
  vtkDataArray* v = cell_data->GetHigherOrderDegrees();
  if (v)
  {
    double degs[3];
    v->GetTuple(cell_id, degs);
    order[0] = degs[0];
    order[1] = degs[1];
  }
  else
  {
    order[0] = order[1] = static_cast<int>(round(std::sqrt(static_cast<int>(numPts)))) - 1;
  }
  order[2] = (order[0] + 1) * (order[1] + 1);
  if (order[2] != numPts)
    vtkGenericWarningMacro(
      "The degrees are direction dependents, and should be set in the input file.");
}

void vtkHigherOrderQuadrilateral::SetUniformOrderFromNumPoints(vtkIdType numPts)
{
  int deg = static_cast<int>(round(std::sqrt(static_cast<int>(numPts)))) - 1;
  this->SetOrder(deg, deg);
  if (static_cast<int>(numPts) != this->Order[2])
    vtkErrorMacro("The degrees are direction dependents, and should be set in the input file.");
}

void vtkHigherOrderQuadrilateral::SetOrder(int s, int t)
{
  if (this->PointParametricCoordinates && (Order[0] != s || Order[1] != t))
    this->PointParametricCoordinates->Reset();
  Order[0] = s;
  Order[1] = t;
  Order[2] = (s + 1) * (t + 1);
}

const int* vtkHigherOrderQuadrilateral::GetOrder()
{
  //   The interpolation routines can handle different order along each axis
  //   The connectivity array contains three additional entries at the end which specify the Order
  //   in s, t, and u The unstructure grid calls SetOrder with those three additional entries
  vtkIdType numPts = this->Points->GetNumberOfPoints();
  if (this->Order[2] != numPts)
  {
    if (numPts == 4)
      this->SetUniformOrderFromNumPoints(numPts);
    else
      vtkErrorMacro("The degrees might be direction dependents, and should be set before GetOrder "
                    "is called. numPts is "
        << numPts << " and Order[2] " << Order[2]);
  }
  return this->Order;
}

bool vtkHigherOrderQuadrilateral::PointCountSupportsUniformOrder(vtkIdType pointsPerCell)
{
  // Determine if sqrt(N) is integral (and if so, what is it?).
  vtkIdType nn = pointsPerCell;
  int h = nn % 0x0f; // Perfect squares in base 16 must end in 0, 1, 4, or 9.
  if (h > 9 || (h > 1 && h < 4) || (h > 4 && h < 9))
  {
    // Trivially reject numbers with a bad final digit.
    return false;
  }
  // There's a chance we have a perfect square, do the hard work.
  int root = std::floor(std::sqrt(nn) + 0.5);
  if (root * root != nn)
  {
    return false;
  }
  return root >= 4;
}
VTK_ABI_NAMESPACE_END
