/**
 * Orthanc - A Lightweight, RESTful DICOM Store
 * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
 * Department, University Hospital of Liege, Belgium
 * Copyright (C) 2017-2018 Osimis S.A., 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.
 *
 * In addition, as a special exception, the copyright holders of this
 * program give permission to link the code of its release with the
 * OpenSSL project's "OpenSSL" library (or with modified versions of it
 * that use the same license as the "OpenSSL" library), and distribute
 * the linked executables. You must obey the GNU General Public License
 * in all respects for all of the code used other than "OpenSSL". If you
 * modify file(s) with this exception, you may extend this exception to
 * your version of the file(s), but you are not obligated to do so. If
 * you do not wish to do so, delete this exception statement from your
 * version. If you delete this exception statement from all source files
 * in the program, then also delete it here.
 *
 * 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 "../PrecompiledHeaders.h"
#include "PamReader.h"

#include "../Endianness.h"
#include "../OrthancException.h"
#include "../Toolbox.h"

#if ORTHANC_SANDBOXED == 0
#  include "../SystemToolbox.h"
#endif

#include <boost/algorithm/string/find.hpp>
#include <boost/lexical_cast.hpp>


namespace Orthanc
{
  static void GetPixelFormat(PixelFormat& format,
                             unsigned int& bytesPerChannel,
                             const unsigned int& maxValue,
                             const unsigned int& channelCount,
                             const std::string& tupleType)
  {
    if (tupleType == "GRAYSCALE" &&
        channelCount == 1)
    {
      switch (maxValue)
      {
        case 255:
          format = PixelFormat_Grayscale8;
          bytesPerChannel = 1;
          return;

        case 65535:
          format = PixelFormat_Grayscale16;
          bytesPerChannel = 2;
          return;

        default:
          throw OrthancException(ErrorCode_NotImplemented);
      }
    }
    else if (tupleType == "RGB" &&
             channelCount == 3)
    {
      switch (maxValue)
      {
        case 255:
          format = PixelFormat_RGB24;
          bytesPerChannel = 1;
          return;

        case 65535:
          format = PixelFormat_RGB48;
          bytesPerChannel = 2;
          return;

        default:
          throw OrthancException(ErrorCode_NotImplemented);
      }
    }
    else
    {
      throw OrthancException(ErrorCode_NotImplemented);
    }
  }

  
  typedef std::map<std::string, std::string>  Parameters;

  
  static std::string LookupStringParameter(const Parameters& parameters,
                                           const std::string& key)
  {
    Parameters::const_iterator found = parameters.find(key);

    if (found == parameters.end())
    {
      throw OrthancException(ErrorCode_BadFileFormat);
    }
    else
    {
      return found->second;
    }
  }
  

  static unsigned int LookupIntegerParameter(const Parameters& parameters,
                                             const std::string& key)
  {
    try
    {
      int value = boost::lexical_cast<int>(LookupStringParameter(parameters, key));

      if (value < 0)
      {
        throw OrthancException(ErrorCode_BadFileFormat);
      }
      else
      {
        return static_cast<unsigned int>(value);
      }
    }
    catch (boost::bad_lexical_cast&)
    {
      throw OrthancException(ErrorCode_BadFileFormat);
    }
  }
  

  void PamReader::ParseContent()
  {
    static const std::string headerDelimiter = "ENDHDR\n";
    
    boost::iterator_range<std::string::const_iterator> headerRange =
      boost::algorithm::find_first(content_, headerDelimiter);

    if (!headerRange)
    {
      throw OrthancException(ErrorCode_BadFileFormat);
    }

    std::string header(static_cast<const std::string&>(content_).begin(), headerRange.begin());

    std::vector<std::string> lines;
    Toolbox::TokenizeString(lines, header, '\n');

    if (lines.size() < 2 ||
        lines.front() != "P7" ||
        !lines.back().empty())
    {
      throw OrthancException(ErrorCode_BadFileFormat);
    }

    Parameters parameters;
    
    for (size_t i = 1; i + 1 < lines.size(); i++)
    {
      std::vector<std::string> tokens;
      Toolbox::TokenizeString(tokens, lines[i], ' ');

      if (tokens.size() != 2)
      {
        throw OrthancException(ErrorCode_BadFileFormat);
      }
      else
      {
        parameters[tokens[0]] = tokens[1];
      }
    }

    const unsigned int width = LookupIntegerParameter(parameters, "WIDTH");
    const unsigned int height = LookupIntegerParameter(parameters, "HEIGHT");
    const unsigned int channelCount = LookupIntegerParameter(parameters, "DEPTH");
    const unsigned int maxValue = LookupIntegerParameter(parameters, "MAXVAL");
    const std::string tupleType = LookupStringParameter(parameters, "TUPLTYPE");

    unsigned int bytesPerChannel;
    PixelFormat format;
    GetPixelFormat(format, bytesPerChannel, maxValue, channelCount, tupleType.c_str());

    unsigned int pitch = width * channelCount * bytesPerChannel;

    if (content_.size() != header.size() + headerDelimiter.size() + pitch * height)
    {
      throw OrthancException(ErrorCode_BadFileFormat);
    }

    size_t offset = content_.size() - pitch * height;
    AssignWritable(format, width, height, pitch, &content_[offset]);

    // Byte swapping if needed
    if (bytesPerChannel != 1 &&
        bytesPerChannel != 2)
    {
      throw OrthancException(ErrorCode_NotImplemented);
    }
    
    if (Toolbox::DetectEndianness() == Endianness_Little &&
        bytesPerChannel == 2)
    {
      for (unsigned int h = 0; h < height; ++h)
      {
        uint16_t* pixel = reinterpret_cast<uint16_t*>(GetRow(h));
        
        for (unsigned int w = 0; w < GetWidth(); ++w, ++pixel)
        {
          // memcpy() is necessary to avoid segmentation fault if the
          // "pixel" pointer is not 16-bit aligned (which is the case
          // if "offset" is an odd number). Check out issue #99:
          // https://bitbucket.org/sjodogne/orthanc/issues/99
          uint16_t v = htobe16(*pixel);
          memcpy(pixel, &v, sizeof(v));
        }
      }
    }
  }

  
#if ORTHANC_SANDBOXED == 0
  void PamReader::ReadFromFile(const std::string& filename)
  {
    SystemToolbox::ReadFile(content_, filename);
    ParseContent();
  }
#endif
  

  void PamReader::ReadFromMemory(const std::string& buffer)
  {
    content_ = buffer;
    ParseContent();
  }
}