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

  Program:   Visualization Toolkit
  Module:    vtkTemporalInterpolator.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 "vtkTemporalInterpolator.h"

#include "vtkArrayDispatch.h"
#include "vtkCellData.h"
#include "vtkCompositeDataIterator.h"
#include "vtkCompositeDataPipeline.h"
#include "vtkDataArrayRange.h"
#include "vtkDataSet.h"
#include "vtkDoubleArray.h"
#include "vtkFloatArray.h"
#include "vtkInformation.h"
#include "vtkInformationVector.h"
#include "vtkMultiBlockDataSet.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkPointSet.h"
#include "vtkSmartPointer.h"
#include "vtkStreamingDemandDrivenPipeline.h"

#include <algorithm>
#include <vector>

vtkStandardNewMacro(vtkTemporalInterpolator);

//------------------------------------------------------------------------------
vtkTemporalInterpolator::vtkTemporalInterpolator()
{
  this->DiscreteTimeStepInterval = 0.0; // non value
  this->ResampleFactor = 0;             // non value
  this->Ratio = 0.0;
  this->DeltaT = 0.0;
  this->Tfrac = 0.0;

  this->SetNumberOfInputPorts(1);
  this->SetNumberOfOutputPorts(1);

  this->CacheData = true;
  this->NumberOfCacheEntries = 2;
}

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

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

  os << indent << "ResampleFactor: " << this->ResampleFactor << "\n";
  os << indent << "DiscreteTimeStepInterval: " << this->DiscreteTimeStepInterval << "\n";
}

//------------------------------------------------------------------------------
int vtkTemporalInterpolator::FillInputPortInformation(int port, vtkInformation* info)
{
  if (port == 0)
  {
    info->Set(vtkAlgorithm::INPUT_REQUIRED_DATA_TYPE(), "vtkDataObject");
  }
  return 1;
}

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

//------------------------------------------------------------------------------
int vtkTemporalInterpolator::RequestDataObject(
  vtkInformation*, vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  if (this->GetNumberOfInputPorts() == 0 || this->GetNumberOfOutputPorts() == 0)
  {
    return 1;
  }

  vtkInformation* inInfo = inputVector[0]->GetInformationObject(0);
  if (!inInfo)
  {
    return 0;
  }
  vtkDataObject* input = inInfo->Get(vtkDataObject::DATA_OBJECT());

  if (input)
  {
    // for each output
    for (int i = 0; i < this->GetNumberOfOutputPorts(); ++i)
    {
      vtkInformation* info = outputVector->GetInformationObject(i);
      vtkDataObject* output = info->Get(vtkDataObject::DATA_OBJECT());

      if (!output || !output->IsA(input->GetClassName()))
      {
        vtkDataObject* newOutput = input->NewInstance();
        info->Set(vtkDataObject::DATA_OBJECT(), newOutput);
        newOutput->Delete();
      }
    }
    return 1;
  }
  return 0;
}

//------------------------------------------------------------------------------
// Change the information
int vtkTemporalInterpolator::RequestInformation(vtkInformation* vtkNotUsed(request),
  vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  // get the info objects
  vtkInformation* outInfo = outputVector->GetInformationObject(0);
  vtkInformation* inInfo = inputVector[0]->GetInformationObject(0);

  //
  // find time on input
  //
  int numTimes = 0;
  double* inTimes = nullptr;
  double outRange[2];

  if (inInfo->Has(vtkStreamingDemandDrivenPipeline::TIME_STEPS()))
  {
    inTimes = inInfo->Get(vtkStreamingDemandDrivenPipeline::TIME_STEPS());
    numTimes = inInfo->Length(vtkStreamingDemandDrivenPipeline::TIME_STEPS());

    outRange[0] = inTimes[0];
    outRange[1] = inTimes[numTimes - 1];
    outInfo->Set(vtkStreamingDemandDrivenPipeline::TIME_RANGE(), outRange, 2);
  }

  // Can we continue
  if (numTimes < 2)
  {
    vtkErrorMacro(<< "Not enough input time steps for interpolation");
    return 0;
  }

  //
  // Now compute the interpolated output times
  //
  if (this->DiscreteTimeStepInterval > 0.0)
  {
    //
    // We know the input has got N time steps,
    // how many output steps are we producing, and what are they.
    //
    int NumberOfOutputTimeSteps =
      1 + static_cast<int>(0.5 + ((outRange[1] - outRange[0]) / this->DiscreteTimeStepInterval));

    // Generate list of new output time step values
    std::vector<double> OutputTimeValues;
    OutputTimeValues.reserve(NumberOfOutputTimeSteps);
    for (int i = 0; i < NumberOfOutputTimeSteps; i++)
    {
      OutputTimeValues.push_back((double)(i) * this->DiscreteTimeStepInterval + outRange[0]);
    }
    outInfo->Set(vtkStreamingDemandDrivenPipeline::TIME_STEPS(), &OutputTimeValues[0],
      NumberOfOutputTimeSteps);
  }
  else if (this->ResampleFactor > 0)
  {
    // Generate list of new output time step values
    std::vector<double> OutputTimeValues;
    OutputTimeValues.reserve(numTimes * this->ResampleFactor);
    for (int i = 1; i < numTimes; i++)
    {
      double t0 = inTimes[i - 1];
      double t1 = inTimes[i];
      double step = (t1 - t0) / (double)this->ResampleFactor;
      for (int j = 0; j < this->ResampleFactor; j++)
      {
        double newT = t0 + j * step;
        OutputTimeValues.push_back(newT);
      }
    }
    outInfo->Set(vtkStreamingDemandDrivenPipeline::TIME_STEPS(), &OutputTimeValues[0],
      static_cast<int>(OutputTimeValues.size()));
  }
  else
  {
    // unset the time steps if they are set
    if (outInfo->Has(vtkStreamingDemandDrivenPipeline::TIME_STEPS()))
    {
      outInfo->Remove(vtkStreamingDemandDrivenPipeline::TIME_STEPS());
    }
  }
  return 1;
}

//------------------------------------------------------------------------------
int vtkTemporalInterpolator::Execute(vtkInformation*,
  const std::vector<vtkSmartPointer<vtkDataObject>>& inputs, vtkInformationVector* outputVector)
{
  vtkInformation* outInfo = outputVector->GetInformationObject(0);
  vtkDataObject* outData = vtkDataObject::GetData(outInfo);

  // get the requested update times
  double upTime = outInfo->Get(vtkStreamingDemandDrivenPipeline::UPDATE_TIME_STEP());

  const int numTimeSteps = static_cast<int>(inputs.size());

  // below the range
  if (numTimeSteps == 1)
  {
    // pass the lowest data
    outData->ShallowCopy(inputs[0]);
  }
  else if (numTimeSteps == 2)
  {
    auto& data0 = inputs[0];
    auto& data1 = inputs[1];
    if (data0 == nullptr && data1 == nullptr)
    {
      vtkErrorMacro("Null data set");
      return 0;
    }

    // interpolate i-1 and i
    double t0 = data0->GetInformation()->Get(vtkDataObject::DATA_TIME_STEP());
    double t1 = data1->GetInformation()->Get(vtkDataObject::DATA_TIME_STEP());
    this->Ratio = (upTime - t0) / (t1 - t0);
    vtkSmartPointer<vtkDataObject> newOutput;
    newOutput.TakeReference(this->InterpolateDataObject(data0, data1, this->Ratio));
    outData->ShallowCopy(newOutput);
  }

  // @TODO remove this when we move to new time framework
  // stamp the new temporal dataset with a time key (old style of management)
  outData->GetInformation()->Set(vtkDataObject::DATA_TIME_STEP(), upTime);

  vtkSmartPointer<vtkDoubleArray> originalTimes = vtkSmartPointer<vtkDoubleArray>::New();
  originalTimes->SetName("OriginalTimeSteps");
  originalTimes->SetNumberOfTuples(numTimeSteps);
  for (int i = 0; i < numTimeSteps; i++)
  {
    originalTimes->SetValue(i, inputs[i]->GetInformation()->Get(vtkDataObject::DATA_TIME_STEP()));
  }
  outData->GetFieldData()->AddArray(originalTimes);
  return 1;
}

//------------------------------------------------------------------------------
int vtkTemporalInterpolator::RequestUpdateExtent(vtkInformation* vtkNotUsed(request),
  vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  // get the info objects
  vtkInformation* outInfo = outputVector->GetInformationObject(0);
  vtkInformation* inInfo = inputVector[0]->GetInformationObject(0);

  // find the required input time steps and request them
  if (outInfo->Has(vtkStreamingDemandDrivenPipeline::UPDATE_TIME_STEP()))
  {
    // get the update times
    double upTime = outInfo->Get(vtkStreamingDemandDrivenPipeline::UPDATE_TIME_STEP());

    // get the available input times
    double* inTimes = inInfo->Get(vtkStreamingDemandDrivenPipeline::TIME_STEPS());
    int numInTimes = inInfo->Length(vtkStreamingDemandDrivenPipeline::TIME_STEPS());

    // only if the input is not continuous should we do anything
    if (inTimes)
    {
      // compute request times f
      double inUpTimes[2];
      int numInUpTimes(0);

      // for each requested time mark the required input times
      numInUpTimes = 0;
      // below the range
      if (upTime <= inTimes[0])
      {
        inUpTimes[numInUpTimes++] = inTimes[0];
      }
      // above the range?
      else if (upTime >= inTimes[numInTimes - 1])
      {
        inUpTimes[numInUpTimes++] = inTimes[numInTimes - 1];
      }
      // in the middle
      else
      {
        int i = 0;
        while (upTime > inTimes[i])
        {
          ++i;
        }
        inUpTimes[numInUpTimes++] = inTimes[i - 1];
        inUpTimes[numInUpTimes++] = inTimes[i];
      }

      inInfo->Set(vtkMultiTimeStepAlgorithm::UPDATE_TIME_STEPS(), inUpTimes, numInUpTimes);
    }
  }
  return 1;
}

//------------------------------------------------------------------------------
vtkTemporalInterpolator::ArrayMatch vtkTemporalInterpolator::VerifyArrays(
  vtkDataArray** arrays, int N)
{
  vtkIdType Nt = arrays[0]->GetNumberOfTuples();
  vtkIdType Nc = arrays[0]->GetNumberOfComponents();
  for (int i = 1; i < N; ++i)
  {
    if (arrays[i]->GetNumberOfComponents() != Nc)
    {
      return MISMATCHED_COMPS;
    }
    if (arrays[i]->GetNumberOfTuples() != Nt)
    {
      return MISMATCHED_TUPLES;
    }
  }
  return MATCHED;
}

//------------------------------------------------------------------------------
vtkDataObject* vtkTemporalInterpolator ::InterpolateDataObject(
  vtkDataObject* in1, vtkDataObject* in2, double ratio)
{
  if (vtkDataSet::SafeDownCast(in1))
  {
    //
    // if we have reached the Leaf/DataSet level, we can interpolate directly
    //
    vtkDataSet* inds1 = vtkDataSet::SafeDownCast(in1);
    vtkDataSet* inds2 = vtkDataSet::SafeDownCast(in2);
    return this->InterpolateDataSet(inds1, inds2, ratio);
  }
  else if (vtkCompositeDataSet::SafeDownCast(in1))
  {
    vtkCompositeDataSet* mgds[2];
    mgds[0] = vtkCompositeDataSet::SafeDownCast(in1);
    mgds[1] = vtkCompositeDataSet::SafeDownCast(in2);

    // It is essential that mgds[0] an mgds[1] has the same structure.
    //
    // We need to loop over blocks etc and build up a new dataset
    //
    vtkCompositeDataSet* output = mgds[0]->NewInstance();
    output->CopyStructure(mgds[0]);
    vtkSmartPointer<vtkCompositeDataIterator> iter;
    iter.TakeReference(mgds[0]->NewIterator());

    for (iter->InitTraversal(); !iter->IsDoneWithTraversal(); iter->GoToNextItem())
    {
      vtkDataObject* dataobj1 = iter->GetCurrentDataObject();
      vtkDataObject* dataobj2 = mgds[1]->GetDataSet(iter);
      if (!dataobj1 || !dataobj2)
      {
        vtkWarningMacro("The composite datasets were not identical in structure.");
        continue;
      }
      vtkDataObject* result = this->InterpolateDataObject(dataobj1, dataobj2, ratio);
      if (result)
      {
        output->SetDataSet(iter, result);
        result->Delete();
      }
      else
      {
        vtkErrorMacro(<< "Unexpected error during interpolation");
        // need to clear up memory we may have allocated and lost :(
        return nullptr;
      }
    }
    return output;
  }
  else
  {
    vtkErrorMacro("We cannot yet interpolate this type of dataset");
    return nullptr;
  }
}

//------------------------------------------------------------------------------
vtkDataSet* vtkTemporalInterpolator ::InterpolateDataSet(
  vtkDataSet* in1, vtkDataSet* in2, double ratio)
{
  vtkDataSet* input[2];
  input[0] = in1;
  input[1] = in2;

  //
  vtkDataSet* output = input[0]->NewInstance();
  output->CopyStructure(input[0]);
  //
  // Interpolate points if the dataset is a vtkPointSet
  //
  vtkPointSet* inPointSet1 = vtkPointSet::SafeDownCast(input[0]);
  vtkPointSet* inPointSet2 = vtkPointSet::SafeDownCast(input[1]);
  vtkPointSet* outPointSet = vtkPointSet::SafeDownCast(output);
  if (inPointSet1 && inPointSet2)
  {
    vtkDataArray* outarray = nullptr;
    vtkPoints* outpoints;

    if (inPointSet1->GetNumberOfPoints() > 0 && inPointSet2->GetNumberOfPoints() > 0)
    {
      vtkDataArray* arrays[2];
      arrays[0] = inPointSet1->GetPoints()->GetData();
      arrays[1] = inPointSet2->GetPoints()->GetData();

      // allocate double for output if input is double - otherwise float
      // do a quick check to see if all arrays have the same number of tuples
      if (this->VerifyArrays(arrays, 2) != MATCHED)
      {
        vtkWarningMacro("Interpolation aborted for points because the number of "
                        "tuples/components in each time step are different");
      }
      outarray = this->InterpolateDataArray(ratio, arrays, arrays[0]->GetNumberOfTuples());
      // Do not shallow copy points from either input, because otherwise when
      // we set the actual point coordinate data we overwrite the original
      // we must instantiate a new points object
      // (ie we override the copystrucure above)
      vtkPoints* inpoints = inPointSet1->GetPoints();
      outpoints = inpoints->NewInstance();
      outPointSet->SetPoints(outpoints);
    }
    else
    {
      // not much we can do really
      outpoints = vtkPoints::New();
      outPointSet->SetPoints(outpoints);
    }

    if (vtkArrayDownCast<vtkDoubleArray>(outarray))
    {
      outpoints->SetDataTypeToDouble();
    }
    else
    {
      outpoints->SetDataTypeToFloat();
    }
    outpoints->SetNumberOfPoints(inPointSet1->GetNumberOfPoints());
    outpoints->SetData(outarray);
    outpoints->Delete();
    if (outarray)
    {
      outarray->Delete();
    }
  }
  //
  // Interpolate pointdata if present
  //
  output->GetPointData()->ShallowCopy(input[0]->GetPointData());
  for (int s = 0; s < input[0]->GetPointData()->GetNumberOfArrays(); ++s)
  {
    std::vector<vtkDataArray*> arrays;
    char* scalarname = nullptr;
    for (int i = 0; i < 2; ++i)
    {
      //
      // On some data, the scalar arrays are consistent but ordered
      // differently on each time step, so we will fetch them by name if
      // possible.
      //
      if (i == 0 || (scalarname == nullptr))
      {
        vtkDataArray* dataarray = input[i]->GetPointData()->GetArray(s);
        scalarname = dataarray->GetName();
        arrays.push_back(dataarray);
      }
      else
      {
        vtkDataArray* dataarray = input[i]->GetPointData()->GetArray(scalarname);
        arrays.push_back(dataarray);
      }
    }
    if (arrays[1])
    {
      // do a quick check to see if all arrays have the same number of tuples
      if (this->VerifyArrays(&arrays[0], 2) != MATCHED)
      {
        vtkWarningMacro(<< "Interpolation aborted for array "
                        << (scalarname ? scalarname : "(unnamed array)")
                        << " because the number of tuples/components"
                        << " in each time step are different");
      }
      else
      {
        // allocate double for output if input is double - otherwise float
        vtkDataArray* outarray =
          this->InterpolateDataArray(ratio, &arrays[0], arrays[0]->GetNumberOfTuples());
        output->GetPointData()->AddArray(outarray);
        outarray->Delete();
      }
    }
    else
    {
      vtkDebugMacro(<< "Interpolation aborted for point array "
                    << (scalarname ? scalarname : "(unnamed array)")
                    << " because the array was not found"
                    << " in the second time step");
    }
  }
  //
  // Interpolate celldata if present
  //
  output->GetCellData()->ShallowCopy(input[0]->GetCellData());
  for (int s = 0; s < input[0]->GetCellData()->GetNumberOfArrays(); ++s)
  {
    // copy the structure
    std::vector<vtkDataArray*> arrays;
    char* scalarname = nullptr;
    for (int i = 0; i < 2; ++i)
    {
      //
      // On some data, the scalar arrays are consistent but ordered
      // differently on each time step, so we will fetch them by name if
      // possible.
      //
      if (i == 0 || (scalarname == nullptr))
      {
        vtkDataArray* dataarray = input[i]->GetCellData()->GetArray(s);
        scalarname = dataarray->GetName();
        arrays.push_back(dataarray);
      }
      else
      {
        vtkDataArray* dataarray = input[i]->GetCellData()->GetArray(scalarname);
        arrays.push_back(dataarray);
      }
    }
    if (arrays[1])
    {
      // do a quick check to see if all arrays have the same number of tuples
      if (this->VerifyArrays(&arrays[0], 2) != MATCHED)
      {
        vtkWarningMacro(<< "Interpolation aborted for array "
                        << (scalarname ? scalarname : "(unnamed array)")
                        << " because the number of tuples/components"
                        << " in each time step are different");
      }
      // allocate double for output if input is double - otherwise float
      vtkDataArray* outarray =
        this->InterpolateDataArray(ratio, &arrays[0], arrays[0]->GetNumberOfTuples());
      output->GetCellData()->AddArray(outarray);
      outarray->Delete();
    }
    else
    {
      vtkDebugMacro(<< "Interpolation aborted for cell array "
                    << (scalarname ? scalarname : "(unnamed array)")
                    << " because the array was not found"
                    << " in the second time step");
    }
  }
  return output;
}

namespace
{
struct vtkTemporalExecute
{
  //----------------------------------------------------------------------------
  // This templated function executes the filter for any type of data.
  template <typename ArrayIn1, typename ArrayIn2, typename ArrayOut>
  void operator()(ArrayIn1* input1, ArrayIn2* input2, ArrayOut* output, double ratio) const
  {
    using T = vtk::GetAPIType<ArrayIn1>;
    const double oneMinusRatio = 1.0 - ratio;
    auto in1 = vtk::DataArrayValueRange(input1);
    auto in2 = vtk::DataArrayValueRange(input2);
    auto out = vtk::DataArrayValueRange(output);

    for (vtkIdType i = 0; i < in1.size(); i++)
    {
      out[i] = static_cast<T>(in1[i] * oneMinusRatio + in2[i] * ratio);
    }
  }
};
}

//------------------------------------------------------------------------------
vtkDataArray* vtkTemporalInterpolator ::InterpolateDataArray(
  double ratio, vtkDataArray** arrays, vtkIdType numTuples)
{
  //
  // Create the output
  //
  vtkAbstractArray* aa = vtkDataArray::CreateArray(arrays[0]->GetDataType());
  vtkDataArray* output = vtkArrayDownCast<vtkDataArray>(aa);

  int numComp = arrays[0]->GetNumberOfComponents();

  //
  // initialize the output
  //
  output->SetNumberOfComponents(numComp);
  output->SetNumberOfTuples(numTuples);
  output->SetName(arrays[0]->GetName());

  if (!vtkArrayDispatch::Dispatch3SameValueType::Execute(
        arrays[0], arrays[1], output, vtkTemporalExecute{}, ratio))
  {
    vtkTemporalExecute{}(arrays[0], arrays[1], output, ratio);
  }

  return output;
}
