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

#include "vtkDataArray.h"
#include "vtkImageData.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkStreamingDemandDrivenPipeline.h"
#include <vtksys/SystemTools.hxx>

#include <cctype>

VTK_ABI_NAMESPACE_BEGIN
vtkStandardNewMacro(vtkSLCReader);

// Constructor for a vtkSLCReader.
vtkSLCReader::vtkSLCReader()
{
  this->FileName = nullptr;
  this->Error = 0;
}

vtkSLCReader::~vtkSLCReader() = default;

// Decodes an array of eight bit run-length encoded data.
unsigned char* vtkSLCReader::Decode8BitData(unsigned char* in_ptr, int size)
{
  unsigned char* curr_ptr;
  unsigned char* decode_ptr;
  unsigned char* return_ptr;
  unsigned char current_value;
  unsigned char remaining;

  curr_ptr = in_ptr;

  decode_ptr = return_ptr = new unsigned char[size];

  while (true)
  {
    current_value = *(curr_ptr++);

    if (!(remaining = (current_value & 0x7f)))
    {
      break;
    }

    if (current_value & 0x80)
    {
      while (remaining--)
      {
        *(decode_ptr++) = *(curr_ptr++);
      }
    }
    else
    {
      current_value = *(curr_ptr++);
      while (remaining--)
      {
        *(decode_ptr++) = current_value;
      }
    }
  }

  return return_ptr;
}

// This will be needed when we make this an imaging filter.
int vtkSLCReader::RequestInformation(
  vtkInformation* request, vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  FILE* fp;
  int temp;
  double f[3];
  int size[3];
  int magic_num;
  this->Error = 1;

  if (!this->FileName)
  {
    vtkErrorMacro(<< "A FileName must be specified.");
    return 0;
  }

  // Initialize
  if ((fp = vtksys::SystemTools::Fopen(this->FileName, "rb")) == nullptr)
  {
    vtkErrorMacro(<< "File " << this->FileName << " not found");
    return 0;
  }
  this->FileDimensionality = 3;
  if (fscanf(fp, "%d", &magic_num) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed to read magic number");
    fclose(fp);
    return 1;
  }
  if (magic_num != 11111)
  {
    vtkErrorMacro(<< "SLC magic number is not correct");
    fclose(fp);
    return 1;
  }

  f[0] = f[1] = f[2] = 0.0;
  this->SetDataOrigin(f);

  if (fscanf(fp, "%d", size) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed to read size[0]");
    fclose(fp);
    return 1;
  }
  if (fscanf(fp, "%d", size + 1) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed to read size[1]");
    fclose(fp);
    return 1;
  }
  if (fscanf(fp, "%d", size + 2) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed to read size[2]");
    fclose(fp);
    return 1;
  }
  this->SetDataExtent(0, size[0] - 1, 0, size[1] - 1, 0, size[2] - 1);

  // Skip Over bits_per_voxel Field */
  if (fscanf(fp, "%d", &temp) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName
                  << "Failed to skip over bits per pixel");
    fclose(fp);
    return 1;
  }

  if (fscanf(fp, "%lf", f) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed to spacing[0]");
    fclose(fp);
    return 1;
  }
  if (fscanf(fp, "%lf", f + 1) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed to spacing[1]");
    fclose(fp);
    return 1;
  }
  if (fscanf(fp, "%lf", f + 2) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed to spacing[2]");
    fclose(fp);
    return 1;
  }
  this->SetDataSpacing(f);

  // Skip Over unit_type, data_origin, and data_modification
  if (fscanf(fp, "%d", &temp) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed to skip over unit type");
    fclose(fp);
    return 1;
  }
  if (fscanf(fp, "%d", &temp) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed to skip over data origin");
    fclose(fp);
    return 1;
  }
  if (fscanf(fp, "%d", &temp) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName
                  << "Failed to skip over data modification");
    fclose(fp);
    return 1;
  }

  this->SetDataScalarType(VTK_UNSIGNED_CHAR);
  this->SetNumberOfScalarComponents(1);

  fclose(fp);
  return this->Superclass::RequestInformation(request, inputVector, outputVector);
}

// Reads an SLC file and creates a vtkStructuredPoints dataset.
void vtkSLCReader::ExecuteDataWithInformation(
  vtkDataObject* output_do, vtkInformation* vtkNotUsed(outInfo))
{
  vtkImageData* output = vtkImageData::SafeDownCast(output_do);

  FILE* fp;

  int temp;
  int data_compression;
  int plane_size;
  double f[3];
  int size[3];
  int magic_num;
  int z_counter;
  int icon_width, icon_height;
  int compressed_size;

  unsigned char* icon_ptr;
  unsigned char* compressed_ptr;
  unsigned char* scan_ptr = nullptr;

  this->Error = 1;

  if (!this->FileName)
  {
    vtkErrorMacro(<< "A FileName must be specified.");
    return;
  }

  // Initialize
  if ((fp = vtksys::SystemTools::Fopen(this->FileName, "rb")) == nullptr)
  {
    vtkErrorMacro(<< "File " << this->FileName << " not found");
    return;
  }

  if (fscanf(fp, "%d", &magic_num) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed to read magic number");
    fclose(fp);
    return;
  }
  if (magic_num != 11111)
  {
    vtkErrorMacro(<< "SLC magic number is not correct");
    fclose(fp);
    return;
  }

  f[0] = f[1] = f[2] = 0.0;
  output->SetOrigin(f);

  if (fscanf(fp, "%d", size) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed read size[0]");
    fclose(fp);
    return;
  }
  if (fscanf(fp, "%d", size + 1) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed read size[1]");
    fclose(fp);
    return;
  }
  if (fscanf(fp, "%d", size + 2) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed read size[2]");
    fclose(fp);
    return;
  }
  output->SetDimensions(size);

  output->AllocateScalars(VTK_UNSIGNED_CHAR, 1);
  output->GetPointData()->GetScalars()->SetName("SLCImage");

  // Skip Over bits_per_voxel Field */
  if (fscanf(fp, "%d", &temp) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName
                  << "Failed to skip over bits per voxel");
    fclose(fp);
    return;
  }
  if (fscanf(fp, "%lf", f) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed read spacing[0]");
    fclose(fp);
    return;
  }
  if (fscanf(fp, "%lf", f + 1) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed read spacing[1]");
    fclose(fp);
    return;
  }
  if (fscanf(fp, "%lf", f + 2) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed read spacing[2]");
    fclose(fp);
    return;
  }
  output->SetSpacing(f);

  // Skip Over unit_type, data_origin, and data_modification
  if (fscanf(fp, "%d", &temp) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed to skip over unit type");
    fclose(fp);
    return;
  }
  if (fscanf(fp, "%d", &temp) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed to skip over data origin");
    fclose(fp);
    return;
  }
  if (fscanf(fp, "%d", &temp) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName
                  << "Failed to skip over data modification");
    fclose(fp);
    return;
  }

  if (fscanf(fp, "%d\n", &data_compression) != 1)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed to read data compression");
    fclose(fp);
    return;
  }

  plane_size = size[0] * size[1];
#ifndef NDEBUG
  int volume_size = plane_size * size[2];
#endif

  // Skip Over Icon
  if (fscanf(fp, "%d %d X", &icon_width, &icon_height) != 2)
  {
    vtkErrorMacro(<< "Error reading file: " << this->FileName << "Failed to skip over icon");
    fclose(fp);
    return;
  }
  icon_ptr = new unsigned char[(icon_width * icon_height)];

  if (fread(icon_ptr, (icon_width * icon_height), 1, fp) != 1)
  {
    vtkErrorMacro(
      "SLCReader error reading file: " << this->FileName << " Premature EOF while reading icon.");
    delete[] icon_ptr;
    fclose(fp);
    return;
  }
  if (fread(icon_ptr, (icon_width * icon_height), 1, fp) != 1)
  {
    vtkErrorMacro(
      "SLCReader error reading file: " << this->FileName << " Premature EOF while reading icon.");
    delete[] icon_ptr;
    fclose(fp);
    return;
  }
  if (fread(icon_ptr, (icon_width * icon_height), 1, fp) != 1)
  {
  }

  delete[] icon_ptr;

  // Read In Data Plane By Plane
  for (z_counter = 0; z_counter < size[2]; z_counter++)
  {
    if (!(z_counter % 10) && !z_counter)
    {
      this->UpdateProgress((float)z_counter / size[2]);
    }

    // Read a single plane into temp memory
    switch (data_compression)
    {
      case 0:

        if (!scan_ptr)
        {
          scan_ptr = new unsigned char[plane_size];
        }

        if (fread(scan_ptr, 1, plane_size, fp) != (unsigned int)plane_size)
        {
          vtkErrorMacro(<< "Unable to read slice " << z_counter << " from SLC File");
          fclose(fp);
          return;
        }

        break;

      case 1:

        delete[] scan_ptr;

        if (fscanf(fp, "%d X", &compressed_size) != 1)
        {
          vtkErrorMacro(<< "Error reading file: " << this->FileName
                        << "Failed to read compressed size");
          fclose(fp);
          return;
        }

        compressed_ptr = new unsigned char[compressed_size];

        if (fread(compressed_ptr, 1, compressed_size, fp) != (unsigned int)compressed_size)
        {
          vtkErrorMacro(<< "Unable to read compressed slice " << z_counter << " from SLC File");
          delete[] compressed_ptr;
          fclose(fp);
          return;
        }

        scan_ptr = this->Decode8BitData(compressed_ptr, plane_size);
        delete[] compressed_ptr;

        break;
      default:
        vtkErrorMacro(<< "Unknown SLC compression type: " << data_compression);
        fclose(fp);
        return;
    }
    void* outputSlice = output->GetScalarPointer(0, 0, z_counter);
    if (outputSlice && scan_ptr)
    {
      memcpy(outputSlice, scan_ptr, plane_size);
    }
  }

  delete[] scan_ptr;

  vtkDebugMacro(<< "Read " << volume_size << " points");

  fclose(fp);
  this->Error = 0;
}

int vtkSLCReader::CanReadFile(const char* fname)
{
  FILE* fp;
  int magic_num = 0;
  if ((fp = vtksys::SystemTools::Fopen(fname, "rb")) == nullptr)
  {
    return 0;
  }

  if (fscanf(fp, "%d", &magic_num) != 1)
  {
    fclose(fp);
    return 0;
  }
  if (magic_num != 11111)
  {
    fclose(fp);
    return 0;
  }
  fclose(fp);
  return 3;
}

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

  os << indent << "Error: " << this->Error << "\n";
  os << indent << "File Name: " << (this->FileName ? this->FileName : "(none)") << "\n";
}
VTK_ABI_NAMESPACE_END
