/**
 * Stone of Orthanc
 * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
 * Department, University Hospital of Liege, Belgium
 * Copyright (C) 2017-2020 Osimis S.A., Belgium
 *
 * This program is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Affero 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
 * Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 **/


#include "LookupTableTextureSceneLayer.h"

#include <Core/Images/Image.h>
#include <Core/Images/ImageProcessing.h>
#include <Core/OrthancException.h>

namespace OrthancStone
{
  LookupTableTextureSceneLayer::LookupTableTextureSceneLayer(const Orthanc::ImageAccessor& texture) :
    applyLog_(false)
  {
    {
      std::unique_ptr<Orthanc::ImageAccessor> t(
        new Orthanc::Image(Orthanc::PixelFormat_Float32, 
                           texture.GetWidth(), 
                           texture.GetHeight(), 
                           false));

      Orthanc::ImageProcessing::Convert(*t, texture);
      SetTexture(t.release());
    }

    SetLookupTableGrayscale(); // simple ramp between 0 and 255
    SetRange(0, 1);
  }


  void LookupTableTextureSceneLayer::SetLookupTableGrayscale()
  {
    std::vector<uint8_t> rgb(3 * 256);

    for (size_t i = 0; i < 256; i++)
    {
      rgb[3 * i]     = static_cast<uint8_t>(i);
      rgb[3 * i + 1] = static_cast<uint8_t>(i);
      rgb[3 * i + 2] = static_cast<uint8_t>(i);
    }

    SetLookupTableRgb(rgb);
  }  


  void LookupTableTextureSceneLayer::SetLookupTableRgb(const std::vector<uint8_t>& lut)
  {
    if (lut.size() != 3 * 256)
    {
      throw Orthanc::OrthancException(Orthanc::ErrorCode_InternalError);
    }

    lut_.resize(4 * 256);

    for (size_t i = 0; i < 256; i++)
    {
      // Premultiplied alpha
      
      if (i == 0)
      {
        // Make zero transparent
        lut_[4 * i] = 0;        // R
        lut_[4 * i + 1] = 0;    // G
        lut_[4 * i + 2] = 0;    // B
        lut_[4 * i + 3] = 0;    // A
      }
      else
      {
        float a = static_cast<float>(i) / 255.0f;
        
        float r = static_cast<float>(lut[3 * i]) * a;
        float g = static_cast<float>(lut[3 * i + 1]) * a;
        float b = static_cast<float>(lut[3 * i + 2]) * a;
        
        lut_[4 * i] = static_cast<uint8_t>(std::floor(r));
        lut_[4 * i + 1] = static_cast<uint8_t>(std::floor(g));
        lut_[4 * i + 2] = static_cast<uint8_t>(std::floor(b));
        lut_[4 * i + 3] = static_cast<uint8_t>(std::floor(a * 255.0f));
      }
    }

    IncrementRevision();
  }


  void LookupTableTextureSceneLayer::SetLookupTable(const std::vector<uint8_t>& lut)
  {
    if (lut.size() == 4 * 256)
    {
      lut_ = lut;
      IncrementRevision();
    }
    else if (lut.size() == 3 * 256)
    {
      SetLookupTableRgb(lut);
    }
    else
    {
      throw Orthanc::OrthancException(Orthanc::ErrorCode_ParameterOutOfRange);
    }
  }

  void LookupTableTextureSceneLayer::SetRange(float minValue,
                                              float maxValue)
  {
    if (minValue > maxValue)
    {
      throw Orthanc::OrthancException(Orthanc::ErrorCode_ParameterOutOfRange);
    }
    else
    {
      minValue_ = minValue;
      maxValue_ = maxValue;
      IncrementRevision();
    }
  }

  void LookupTableTextureSceneLayer::SetApplyLog(bool apply)
  {
    applyLog_ = apply;
    IncrementRevision();
  }

  void LookupTableTextureSceneLayer::FitRange()
  {
    Orthanc::ImageProcessing::GetMinMaxFloatValue(minValue_, maxValue_, GetTexture());
    assert(minValue_ <= maxValue_);
    // TODO: debug to be removed
    if (fabs(maxValue_ - minValue_) < 0.0001) {
      LOG(INFO) << "LookupTableTextureSceneLayer::FitRange(): minValue_ = " << minValue_ << " maxValue_ = " << maxValue_;
    }
    IncrementRevision();
  }

    
  ISceneLayer* LookupTableTextureSceneLayer::Clone() const
  {
    std::unique_ptr<LookupTableTextureSceneLayer> cloned
      (new LookupTableTextureSceneLayer(GetTexture()));


    // TODO: why is windowing_ not copied??????
    cloned->CopyParameters(*this);
    cloned->minValue_ = minValue_;
    cloned->maxValue_ = maxValue_;
    cloned->lut_ = lut_;

    return cloned.release();
  }


  // Templatized function to speed up computations, by avoiding
  // testing conditions on each pixel
  template <bool IsApplyLog,
            Orthanc::PixelFormat TargetFormat>
  static void RenderInternal(Orthanc::ImageAccessor& target,
                             const Orthanc::ImageAccessor& source,
                             float minValue,
                             float slope,
                             const std::vector<uint8_t>& lut)
  {
    static const float LOG_NORMALIZATION = 255.0f / log(1.0f + 255.0f);

    const unsigned int width = source.GetWidth();
    const unsigned int height = source.GetHeight();
    
    for (unsigned int y = 0; y < height; y++)
    {
      const float* p = reinterpret_cast<const float*>(source.GetConstRow(y));
      uint8_t* q = reinterpret_cast<uint8_t*>(target.GetRow(y));

      for (unsigned int x = 0; x < width; x++)
      {
        float v = (*p - minValue) * slope;
        if (v <= 0)
        {
          v = 0;
        }
        else if (v >= 255)
        {
          v = 255;
        }

        if (IsApplyLog)
        {
          // https://theailearner.com/2019/01/01/log-transformation/
          v = LOG_NORMALIZATION * log(1.0f + static_cast<float>(v));
        }

        assert(v >= 0.0f && v <= 255.0f);

        uint8_t vv = static_cast<uint8_t>(v);

        switch (TargetFormat)
        {
          case Orthanc::PixelFormat_BGRA32:
            // For Cairo surfaces
            q[0] = lut[4 * vv + 2];  // B
            q[1] = lut[4 * vv + 1];  // G
            q[2] = lut[4 * vv + 0];  // R
            q[3] = lut[4 * vv + 3];  // A
            break;

          case Orthanc::PixelFormat_RGBA32:
            // For OpenGL
            q[0] = lut[4 * vv + 0];  // R
            q[1] = lut[4 * vv + 1];  // G
            q[2] = lut[4 * vv + 2];  // B
            q[3] = lut[4 * vv + 3];  // A
            break;

          default:
            assert(0);
        }
            
        p++;
        q += 4;
      }
    }
  }
  

  void LookupTableTextureSceneLayer::Render(Orthanc::ImageAccessor& target) const
  {
    assert(sizeof(float) == 4);

    if (!HasTexture())
    {
      throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls);
    }

    const Orthanc::ImageAccessor& source = GetTexture();
    
    if (source.GetFormat() != Orthanc::PixelFormat_Float32 ||
        (target.GetFormat() != Orthanc::PixelFormat_RGBA32 &&
         target.GetFormat() != Orthanc::PixelFormat_BGRA32))
    {
      throw Orthanc::OrthancException(Orthanc::ErrorCode_IncompatibleImageFormat);
    }

    if (source.GetWidth() != target.GetWidth() ||
        source.GetHeight() != target.GetHeight())
    {
      throw Orthanc::OrthancException(Orthanc::ErrorCode_IncompatibleImageSize);
    }

    const float minValue = GetMinValue();
    float slope;

    if (GetMinValue() >= GetMaxValue())
    {
      slope = 0;
    }
    else
    {
      slope = 256.0f / (GetMaxValue() - GetMinValue());
    }

    const std::vector<uint8_t>& lut = GetLookupTable();
    if (lut.size() != 4 * 256)
    {
      throw Orthanc::OrthancException(Orthanc::ErrorCode_InternalError);
    }

    switch (target.GetFormat())
    {
      case Orthanc::PixelFormat_RGBA32:
        if (applyLog_)
        {
          RenderInternal<true, Orthanc::PixelFormat_RGBA32>(target, source, minValue, slope, lut);
        }
        else
        {
          RenderInternal<false, Orthanc::PixelFormat_RGBA32>(target, source, minValue, slope, lut);
        }
        break;

      case Orthanc::PixelFormat_BGRA32:
        if (applyLog_)
        {
          RenderInternal<true, Orthanc::PixelFormat_BGRA32>(target, source, minValue, slope, lut);
        }
        else
        {
          RenderInternal<false, Orthanc::PixelFormat_BGRA32>(target, source, minValue, slope, lut);
        }
        break;

      default:
        throw Orthanc::OrthancException(Orthanc::ErrorCode_InternalError);
    }
  }
}