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

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

#include "vtkObjectFactory.h"
#include "vtkDoubleArray.h"
#include "vtkImageData.h"
#include "vtkImageIterator.h"
#include "vtkImageProgressIterator.h"
#include "vtkInformation.h"
#include "vtkInformationVector.h"
#include "vtkStreamingDemandDrivenPipeline.h"
#include "vtkDataSetAttributes.h"

vtkStandardNewMacro(vtkImageWeightedSum);

vtkCxxSetObjectMacro(vtkImageWeightedSum,Weights,vtkDoubleArray);
//----------------------------------------------------------------------------
// Description:
// Constructor sets default values
vtkImageWeightedSum::vtkImageWeightedSum()
{
  this->SetNumberOfInputPorts(1);

  // array of weights: need as many weights as inputs
  this->Weights = vtkDoubleArray::New();
  // By default normalize
  this->NormalizeByWeight = 1;
}


//----------------------------------------------------------------------------
vtkImageWeightedSum::~vtkImageWeightedSum()
{
  this->Weights->Delete();
}

//----------------------------------------------------------------------------
void vtkImageWeightedSum::SetWeight(vtkIdType id, double weight)
{
  // Reallocate if needed and pass the new weight
  this->Weights->InsertValue(id, weight);
}

//----------------------------------------------------------------------------
double vtkImageWeightedSum::CalculateTotalWeight()
{
  double totalWeight = 0.0;

  for(int i = 0; i < this->Weights->GetNumberOfTuples(); ++i)
  {
    totalWeight += this->Weights->GetValue(i);
  }
  return totalWeight;
}

//----------------------------------------------------------------------------
// Description:
// This templated function executes the filter for any type of data.
template <class T>
void vtkImageWeightedSumExecute(vtkImageWeightedSum *self,
                          vtkImageData **inDatas, int numInputs, vtkImageData *outData,
                          int outExt[6], int id, T*)
{
  vtkImageIterator<T> inItsFast[256];
  T* inSIFast[256];
  vtkImageProgressIterator<T> outIt(outData, outExt, self, id);

  double *weights =
    static_cast<vtkDoubleArray *>(self->GetWeights())->GetPointer(0);
  double totalWeight = self->CalculateTotalWeight();
  int normalize = self->GetNormalizeByWeight();
  vtkImageIterator<T> *inIts;
  T* *inSI;
  if( numInputs < 256)
  {
    inIts = inItsFast;
    inSI = inSIFast;
  }
  else
  {
    inIts = new vtkImageIterator<T>[numInputs];
    inSI = new T*[numInputs];
  }

  // Loop through all input ImageData to initialize iterators
  for(int i=0; i < numInputs; ++i)
  {
    inIts[i].Initialize(inDatas[i], outExt);
  }
  // Loop through output pixels
  while (!outIt.IsAtEnd())
  {
    for(int j=0; j < numInputs; ++j)
    {
      inSI[j] = inIts[j].BeginSpan();
    }
    T* outSI = outIt.BeginSpan();
    T* outSIEnd = outIt.EndSpan();
    // Pixel operation
    while (outSI != outSIEnd)
    {
      double sum = 0.;
      for(int k=0; k < numInputs; ++k)
      {
        sum += weights[k] * *inSI[k];
      }
      // Divide only if needed and different from 0
      if (normalize && totalWeight != 0.0)
      {
        sum /= totalWeight;
      }
      *outSI = static_cast<T>(sum); // do the cast only at the end
      outSI++;
      for(int l=0; l < numInputs; ++l)
      {
        inSI[l]++;
      }
    }
    for(int j=0; j < numInputs; ++j)
    {
      inIts[j].NextSpan();
    }
    outIt.NextSpan();
  }

  if( numInputs >= 256)
  {
    delete[] inIts;
    delete[] inSI;
  }
}

//----------------------------------------------------------------------------
int vtkImageWeightedSum::RequestInformation (
  vtkInformation * vtkNotUsed(request),
  vtkInformationVector** inputVector,
  vtkInformationVector *outputVector)
{
  // get the info objects
  vtkInformation* outInfo = outputVector->GetInformationObject(0);

  int numInputs = this->GetNumberOfInputConnections(0);
  if(!numInputs)
  {
    return 0;
  }
  int outputType = VTK_DOUBLE;
  vtkInformation *info = inputVector[0]->GetInformationObject(0);
  vtkInformation *scalarInfo = vtkDataObject::GetActiveFieldInformation(info,
    vtkDataObject::FIELD_ASSOCIATION_POINTS, vtkDataSetAttributes::SCALARS);
  if (scalarInfo)
  {
    outputType = scalarInfo->Get( vtkDataObject::FIELD_ARRAY_TYPE() );
  }
  int type;
  for (int whichInput = 1; whichInput < numInputs; whichInput++)
  {
    vtkInformation *inInfo = inputVector[0]->GetInformationObject(whichInput);
    vtkInformation *inScalarInfo = vtkDataObject::GetActiveFieldInformation(inInfo,
      vtkDataObject::FIELD_ASSOCIATION_POINTS, vtkDataSetAttributes::SCALARS);
    if (inScalarInfo)
    {
      type = inScalarInfo->Get( vtkDataObject::FIELD_ARRAY_TYPE() );
      // Should we also check weight[whichInput] != 0
      if( type != outputType )
      {
        // Could be more fancy
        outputType = VTK_DOUBLE;
      }
    }
  }
  vtkDataObject::SetPointDataActiveScalarInfo(outInfo, outputType, 1);
  return 1;
}

//----------------------------------------------------------------------------
// Description:
// This method is passed a input and output data, and executes the filter
// algorithm to fill the output from the input.
// It just executes a switch statement to call the correct function for
// the datas data types.
void vtkImageWeightedSum::ThreadedRequestData (
  vtkInformation * vtkNotUsed( request ),
  vtkInformationVector** vtkNotUsed( inputVector ),
  vtkInformationVector * vtkNotUsed( outputVector ),
  vtkImageData ***inData,
  vtkImageData **outData,
  int outExt[6], int id)
{
  if (inData[0][0] == nullptr)
  {
    vtkErrorMacro(<< "Input " << 0 << " must be specified.");
    return;
  }

  int numInputs = this->GetNumberOfInputConnections(0);
  int numWeights = this->Weights->GetNumberOfTuples();
  if(numWeights != numInputs)
  {
    if (id == 0)
    {
      vtkErrorMacro("ThreadedRequestData: There are " << numInputs
                    << " vtkImageData inputs provided but only "
                    << numWeights << " weights provided");
    }
    return;
  }

  int scalarType = inData[0][0]->GetScalarType();
  int numComp = inData[0][0]->GetNumberOfScalarComponents();
  for (int i = 1; i < numInputs; ++i)
  {
    int otherType = inData[0][i]->GetScalarType();
    int otherComp = inData[0][i]->GetNumberOfScalarComponents();
    if (otherType != scalarType || otherComp != numComp)
    {
      if (id == 0)
      {
        vtkErrorMacro("ThreadedRequestData: Input " << i
                      << " has " << otherComp << " components of type "
                      << otherType << ", but input 0 has " << numComp
                      << " components of type " << scalarType);
      }
      return;
    }
  }

  switch (scalarType)
  {
    vtkTemplateMacro(
      vtkImageWeightedSumExecute(this, inData[0], numInputs,
        outData[0], outExt, id, static_cast<VTK_TT *>(nullptr))
      );
    default:
      if (id == 0)
      {
        vtkErrorMacro(<< "Execute: Unknown ScalarType");
      }
      return;
  }
}

//----------------------------------------------------------------------------
int vtkImageWeightedSum::FillInputPortInformation(int i, vtkInformation* info)
{
  info->Set(vtkAlgorithm::INPUT_IS_REPEATABLE(), 1);
  return this->Superclass::FillInputPortInformation(i,info);
}

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

  // objects
  os << indent << "NormalizeByWeight: " <<
    (this->NormalizeByWeight ? "On" : "Off" ) << "\n";
  os << indent << "Weights: " << this->Weights << "\n";
  this->Weights->PrintSelf(os,indent.GetNextIndent());
}