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

#include "vtkGenericAdaptorCell.h"
#include "vtkGenericAttribute.h"
#include "vtkGenericAttributeCollection.h"
#include "vtkGenericDataSet.h"
#include "vtkObjectFactory.h"
#include <cassert>
#include <cmath>

VTK_ABI_NAMESPACE_BEGIN
vtkStandardNewMacro(vtkAttributesErrorMetric);

//------------------------------------------------------------------------------
vtkAttributesErrorMetric::vtkAttributesErrorMetric()
{
  this->AttributeTolerance = 0.1;         // arbitrary
  this->AbsoluteAttributeTolerance = 0.1; // arbitrary
  this->SquareAbsoluteAttributeTolerance =
    this->AbsoluteAttributeTolerance * this->AbsoluteAttributeTolerance;
  this->Range = 0;
  this->DefinedByAbsolute = 1;
}

//------------------------------------------------------------------------------
vtkAttributesErrorMetric::~vtkAttributesErrorMetric() = default;

//------------------------------------------------------------------------------
// Description:
// Set the absolute attribute accuracy to `value'. See
// GetAbsoluteAttributeTolerance() for details.
// \pre valid_range_value: value>0
void vtkAttributesErrorMetric::SetAbsoluteAttributeTolerance(double value)
{
  assert("pre: valid_range_value" && value > 0);
  if (this->AbsoluteAttributeTolerance != value || !this->DefinedByAbsolute)
  {
    this->AbsoluteAttributeTolerance = value;
    this->SquareAbsoluteAttributeTolerance =
      this->AbsoluteAttributeTolerance * this->AbsoluteAttributeTolerance;
    this->Range = 0;
    this->DefinedByAbsolute = 1;
    this->Modified();
  }
}

//------------------------------------------------------------------------------
// Description:
// Set the relative attribute accuracy to `value'. See
// GetAttributeTolerance() for details.
// \pre valid_range_value: value>0 && value<1
void vtkAttributesErrorMetric::SetAttributeTolerance(double value)
{
  assert("pre: valid_range_value" && value > 0 && value < 1);
  if (this->AttributeTolerance != value || this->DefinedByAbsolute)
  {
    this->AttributeTolerance = value;
    this->DefinedByAbsolute = 0;
    this->Modified();
  }
}

//------------------------------------------------------------------------------
int vtkAttributesErrorMetric::RequiresEdgeSubdivision(
  double* leftPoint, double* midPoint, double* rightPoint, double alpha)
{
  assert("pre: leftPoint_exists" && leftPoint != nullptr);
  assert("pre: midPoint_exists" && midPoint != nullptr);
  assert("pre: rightPoint_exists" && rightPoint != nullptr);
  assert("pre: clamped_alpha" && alpha > 0 && alpha < 1);

  int result;
  double ae;
  vtkGenericAttributeCollection* ac;

  this->ComputeSquareAbsoluteAttributeTolerance();

  const int ATTRIBUTE_OFFSET = 6;

  ac = this->DataSet->GetAttributes();
  vtkGenericAttribute* a = ac->GetAttribute(ac->GetActiveAttribute());

  if (this->GenericCell->IsAttributeLinear(a))
  {
    // don't need to do anything:
    ae = 0;
  }
  else
  {
    if (ac->GetActiveComponent() >= 0)
    {
      int i = ac->GetAttributeIndex(ac->GetActiveAttribute()) + ac->GetActiveComponent() +
        ATTRIBUTE_OFFSET;
      double tmp = leftPoint[i] + alpha * (rightPoint[i] - leftPoint[i]) - midPoint[i];
      ae = tmp * tmp;
    }
    else // module of the vector
    {
      int i = ac->GetAttributeIndex(ac->GetActiveAttribute()) + ATTRIBUTE_OFFSET;
      int j = 0;
      int c = ac->GetNumberOfComponents();
      double tmp;
#if 0
      // If x and y are two vectors, we compute: ||x|-|y||
      double interpolatedValueMod=0;
      double midValueMod=0;
      while(j<c)
      {
        tmp=leftPoint[i+j]+alpha*(rightPoint[i+j]-leftPoint[i+j]);
        interpolatedValueMod+=tmp*tmp;
        tmp=midPoint[i+j];
        midValueMod+=tmp*tmp;
        ++j;
      }
      tmp=sqrt(midValueMod)-sqrt(interpolatedValueMod);
      ae=tmp*tmp;
#else
      // If x and y are two vectors, we compute: |x-y|
      // We should compute ||x|-|y|| but |x-y| is usually enough
      // and tends to produce less degenerated edges.
      // Remind that: ||x|-|y||<=|x-y|
      ae = 0;
      while (j < c)
      {
        tmp = leftPoint[i + j] + alpha * (rightPoint[i + j] - leftPoint[i + j]) - midPoint[i + j];
        ae += tmp * tmp;
        ++j;
      }
#endif
    }
    assert("check: positive_ae" && ae >= 0);
  }

  if (this->SquareAbsoluteAttributeTolerance == 0)
  {
    result = fabs(ae) > 0.0001;
  }
  else
  {
    result = ae > this->SquareAbsoluteAttributeTolerance;
  }
  return result;
}

//------------------------------------------------------------------------------
// Description:
// Return the error at the mid-point. The type of error depends on the state
// of the concrete error metric. For instance, it can return an absolute
// or relative error metric.
// See RequiresEdgeSubdivision() for a description of the arguments.
// \post positive_result: result>=0
double vtkAttributesErrorMetric::GetError(
  double* leftPoint, double* midPoint, double* rightPoint, double alpha)
{
  assert("pre: leftPoint_exists" && leftPoint != nullptr);
  assert("pre: midPoint_exists" && midPoint != nullptr);
  assert("pre: rightPoint_exists" && rightPoint != nullptr);
  assert("pre: clamped_alpha" && alpha > 0 && alpha < 1);

  double ae;
  vtkGenericAttributeCollection* ac;

  this->ComputeSquareAbsoluteAttributeTolerance();

  const int ATTRIBUTE_OFFSET = 6;

  ac = this->DataSet->GetAttributes();
  vtkGenericAttribute* a = ac->GetAttribute(ac->GetActiveAttribute());

  if (this->GenericCell->IsAttributeLinear(a))
  {
    // don't need to do anything:
    ae = 0;
  }
  else
  {
    if (ac->GetActiveComponent() >= 0) // one component
    {
      int i = ac->GetAttributeIndex(ac->GetActiveAttribute()) + ac->GetActiveComponent() +
        ATTRIBUTE_OFFSET;
      double tmp = leftPoint[i] + alpha * (rightPoint[i] - leftPoint[i]) - midPoint[i];
      ae = tmp * tmp;
    }
    else // module of the vector
    {
      // If x and y are two vectors, we compute: |x-y|
      // We should compute ||x|-|y|| but |x-y| is usually enough
      // and tends to produce less degenerated edges.
      // Remind that: ||x|-|y||<=|x-y|
      int i = ac->GetAttributeIndex(ac->GetActiveAttribute()) + ATTRIBUTE_OFFSET;
      int j = 0;
      int c = ac->GetNumberOfComponents();
      double tmp;

      ae = 0;
      while (j < c)
      {
        tmp = leftPoint[i + j] + alpha * (rightPoint[i + j] - leftPoint[i + j]) - midPoint[i + j];
        ae += tmp * tmp;
        ++j;
      }
    }
  }

  double result;

  if (this->Range != 0)
  {
    result = sqrt(ae) / this->Range;
  }
  else
  {
    result = 0;
  }

  assert("post: positive_result" && result >= 0);

  return result;
}

//------------------------------------------------------------------------------
void vtkAttributesErrorMetric::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os, indent);
  os << indent << "AttributeTolerance: " << this->AttributeTolerance << endl;
  os << indent << "AbsoluteAttributeTolerance: " << this->AbsoluteAttributeTolerance << endl;
}

//------------------------------------------------------------------------------
// Description:
// Compute the absolute attribute tolerance, only if the cached value is
// obsolete.
void vtkAttributesErrorMetric::ComputeSquareAbsoluteAttributeTolerance()
{
  if (!this->DefinedByAbsolute)
  {
    if (this->GetMTime() > this->SquareAbsoluteAttributeToleranceComputeTime)
    {
      vtkGenericAttributeCollection* ac = this->DataSet->GetAttributes();
      vtkGenericAttribute* a = ac->GetAttribute(ac->GetActiveAttribute());

      int i = ac->GetActiveComponent();

      double r[2];

      a->GetRange(i, r);

      double tmp = (r[1] - r[0]) * this->AttributeTolerance;

      this->Range = r[1] - r[0];

      this->SquareAbsoluteAttributeTolerance = tmp * tmp;
      this->SquareAbsoluteAttributeToleranceComputeTime.Modified();
      this->AbsoluteAttributeTolerance = sqrt(this->SquareAbsoluteAttributeTolerance);
    }
  }
}
VTK_ABI_NAMESPACE_END
