/**
 * Orthanc - A Lightweight, RESTful DICOM Store
 * Copyright (C) 2012-2015 Sebastien Jodogne, Medical Physics
 * Department, University Hospital of Liege, Belgium
 *
 * This program is free software: you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 **/


#include <map>
#include <string>
#include <stdexcept>
#include <sstream>
#include <boost/lexical_cast.hpp>

#include "OrthancContext.h"
#include "../../../Core/ImageFormats/ImageProcessing.h"

#include <gdcmReader.h>
#include <gdcmImageReader.h>
#include <gdcmImageChangePlanarConfiguration.h>


static void AnswerUnsupportedImage(OrthancPluginRestOutput* output)
{
  OrthancContext::GetInstance().Redirect(output, "/app/images/unsupported.png");
}


static bool GetOrthancPixelFormat(Orthanc::PixelFormat& format,
                                  const gdcm::Image& image)
{
  if (image.GetPlanarConfiguration() != 0 && 
      image.GetPixelFormat().GetSamplesPerPixel() != 1)
  {
    OrthancContext::GetInstance().LogError("Planar configurations are not supported");
    return false;
  }

  if (image.GetPixelFormat().GetSamplesPerPixel() == 1)
  {
    switch (image.GetPixelFormat().GetScalarType())
    {
      case gdcm::PixelFormat::UINT8:
        format = Orthanc::PixelFormat_Grayscale8;
        return true;

      case gdcm::PixelFormat::UINT16:
        format = Orthanc::PixelFormat_Grayscale16;
        return true;

      case gdcm::PixelFormat::INT16:
        format = Orthanc::PixelFormat_SignedGrayscale16;
        return true;

      default:
        return false;
    }
  }
  else if (image.GetPixelFormat().GetSamplesPerPixel() == 3 &&
           image.GetPixelFormat().GetScalarType() == gdcm::PixelFormat::UINT8)
  {
    format = Orthanc::PixelFormat_RGB24;
    return true;
  }
  else if (image.GetPixelFormat().GetSamplesPerPixel() == 4 &&
           image.GetPixelFormat().GetScalarType() == gdcm::PixelFormat::UINT8)
  {
    format = Orthanc::PixelFormat_RGBA32;
    return true;
  }
  
  return false;
}


ORTHANC_PLUGINS_API int32_t DecodeImage(OrthancPluginRestOutput* output,
                                        const char* url,
                                        const OrthancPluginHttpRequest* request)
{
  std::string instance(request->groups[0]);
  std::string outputFormat(request->groups[1]);
  OrthancContext::GetInstance().LogWarning("Using GDCM to decode instance " + instance);

  // Download the request DICOM instance from Orthanc into a memory buffer
  std::string dicom;
  OrthancContext::GetInstance().GetDicomForInstance(dicom, instance);

  // Prepare a memory stream over the DICOM instance
  std::stringstream stream(dicom);

  // Parse the DICOM instance using GDCM
  gdcm::ImageReader imageReader;
  imageReader.SetStream(stream);
  if (!imageReader.Read())
  {
    OrthancContext::GetInstance().LogError("GDCM cannot extract an image from this DICOM instance");
    AnswerUnsupportedImage(output);
    return 0;
  }

  gdcm::Image& image = imageReader.GetImage();


  // Log information about the decoded image
  char tmp[1024];
  sprintf(tmp, "Image format: %dx%d %s with %d color channel(s)", image.GetRows(), image.GetColumns(), 
          image.GetPixelFormat().GetScalarTypeAsString(), image.GetPixelFormat().GetSamplesPerPixel());
  OrthancContext::GetInstance().LogWarning(tmp);


  // Convert planar configuration
  gdcm::ImageChangePlanarConfiguration planar;
  if (image.GetPlanarConfiguration() != 0 && 
      image.GetPixelFormat().GetSamplesPerPixel() != 1)
  {
    OrthancContext::GetInstance().LogWarning("Converting planar configuration to interleaved");
    planar.SetInput(imageReader.GetImage());
    planar.Change();
    image = planar.GetOutput();
  }


  // Create a read-only accessor to the bitmap decoded by GDCM
  Orthanc::PixelFormat format;
  if (!GetOrthancPixelFormat(format, image))
  {
    OrthancContext::GetInstance().LogError("This sample plugin does not support this image format");
    AnswerUnsupportedImage(output);
    return 0;
  }

  Orthanc::ImageAccessor decodedImage;
  std::vector<char> decodedBuffer(image.GetBufferLength());

  if (decodedBuffer.size())
  {
    image.GetBuffer(&decodedBuffer[0]);
    unsigned int pitch = image.GetColumns() * ::Orthanc::GetBytesPerPixel(format);
    decodedImage.AssignWritable(format, image.GetColumns(), image.GetRows(), pitch, &decodedBuffer[0]);
  }
  else
  {
    // Empty image
    decodedImage.AssignWritable(format, 0, 0, 0, NULL);
  }


  // Convert the pixel format from GDCM to the format requested by the REST query
  Orthanc::ImageBuffer converted;
  converted.SetWidth(decodedImage.GetWidth());
  converted.SetHeight(decodedImage.GetHeight());

  if (outputFormat == "preview")
  {
    if (format == Orthanc::PixelFormat_RGB24 ||
        format == Orthanc::PixelFormat_RGBA32)
    {
      // Do not rescale color image
      converted.SetFormat(Orthanc::PixelFormat_RGB24);
    }
    else
    {
      converted.SetFormat(Orthanc::PixelFormat_Grayscale8);

      // Rescale the image to the [0,255] range
      int64_t a, b;
      Orthanc::ImageProcessing::GetMinMaxValue(a, b, decodedImage);

      float offset = -a;
      float scaling = 255.0f / static_cast<float>(b - a);
      Orthanc::ImageProcessing::ShiftScale(decodedImage, offset, scaling);
    }
  }
  else
  {
    if (format == Orthanc::PixelFormat_RGB24 ||
        format == Orthanc::PixelFormat_RGBA32)
    {
      // Do not convert color images to grayscale values (this is Orthanc convention)
      AnswerUnsupportedImage(output);
      return 0;
    }

    if (outputFormat == "image-uint8")
    {
      converted.SetFormat(Orthanc::PixelFormat_Grayscale8);
    }
    else if (outputFormat == "image-uint16")
    {
      converted.SetFormat(Orthanc::PixelFormat_Grayscale16);
    }
    else if (outputFormat == "image-int16")
    {
      converted.SetFormat(Orthanc::PixelFormat_SignedGrayscale16);
    }
    else
    {
      OrthancContext::GetInstance().LogError("Unknown output format: " + outputFormat);
      AnswerUnsupportedImage(output);
      return 0;
    }
  }

  Orthanc::ImageAccessor convertedAccessor(converted.GetAccessor());
  Orthanc::ImageProcessing::Convert(convertedAccessor, decodedImage);

  // Compress the converted image as a PNG file
  OrthancContext::GetInstance().CompressAndAnswerPngImage(output, convertedAccessor);

  return 0;  // Success
}


extern "C"
{
  ORTHANC_PLUGINS_API int32_t OrthancPluginInitialize(OrthancPluginContext* context)
  {
    OrthancContext::GetInstance().Initialize(context);
    OrthancContext::GetInstance().LogWarning("Initializing GDCM decoding");

    // Check the version of the Orthanc core
    if (OrthancPluginCheckVersion(context) == 0)
    {
      OrthancContext::GetInstance().LogError(
        "Your version of Orthanc (" + std::string(context->orthancVersion) +
        ") must be above " + boost::lexical_cast<std::string>(ORTHANC_PLUGINS_MINIMAL_MAJOR_NUMBER) +
        "." + boost::lexical_cast<std::string>(ORTHANC_PLUGINS_MINIMAL_MINOR_NUMBER) +
        "." + boost::lexical_cast<std::string>(ORTHANC_PLUGINS_MINIMAL_REVISION_NUMBER) +
        " to run this plugin");
      return -1;
    }

    OrthancContext::GetInstance().Register("/instances/([^/]+)/(preview|image-uint8|image-uint16|image-int16)", DecodeImage);
    return 0;
  }

  ORTHANC_PLUGINS_API void OrthancPluginFinalize()
  {
    OrthancContext::GetInstance().LogWarning("Finalizing GDCM decoding");
    OrthancContext::GetInstance().Finalize();
  }

  ORTHANC_PLUGINS_API const char* OrthancPluginGetName()
  {
    return "gdcm-decoding";
  }

  ORTHANC_PLUGINS_API const char* OrthancPluginGetVersion()
  {
    return "1.0";
  }
}