/*
 * 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 2
 * 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, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * Copyright 2011, Blender Foundation.
 */

#include "COM_BilateralBlurOperation.h"
#include "BLI_math.h"

#include "RE_pipeline.h"

namespace blender::compositor {

BilateralBlurOperation::BilateralBlurOperation()
{
  this->addInputSocket(DataType::Color);
  this->addInputSocket(DataType::Color);
  this->addOutputSocket(DataType::Color);
  this->flags.complex = true;

  this->m_inputColorProgram = nullptr;
  this->m_inputDeterminatorProgram = nullptr;
}

void BilateralBlurOperation::initExecution()
{
  this->m_inputColorProgram = getInputSocketReader(0);
  this->m_inputDeterminatorProgram = getInputSocketReader(1);
  this->m_space = this->m_data->sigma_space + this->m_data->iter;
  QualityStepHelper::initExecution(COM_QH_INCREASE);
}

void BilateralBlurOperation::executePixel(float output[4], int x, int y, void *data)
{
  // read the determinator color at x, y, this will be used as the reference color for the
  // determinator
  float determinatorReferenceColor[4];
  float determinator[4];
  float tempColor[4];
  float blurColor[4];
  float blurDivider;
  float space = this->m_space;
  float sigmacolor = this->m_data->sigma_color;
  int minx = floor(x - space);
  int maxx = ceil(x + space);
  int miny = floor(y - space);
  int maxy = ceil(y + space);
  float deltaColor;
  this->m_inputDeterminatorProgram->read(determinatorReferenceColor, x, y, data);

  zero_v4(blurColor);
  blurDivider = 0.0f;
  /* TODO(sergey): This isn't really good bilateral filter, it should be
   * using gaussian bell for weights. Also sigma_color doesn't seem to be
   * used correct at all.
   */
  for (int yi = miny; yi < maxy; yi += QualityStepHelper::getStep()) {
    for (int xi = minx; xi < maxx; xi += QualityStepHelper::getStep()) {
      // read determinator
      this->m_inputDeterminatorProgram->read(determinator, xi, yi, data);
      deltaColor = (fabsf(determinatorReferenceColor[0] - determinator[0]) +
                    fabsf(determinatorReferenceColor[1] - determinator[1]) +
                    fabsf(determinatorReferenceColor[2] -
                          determinator[2]));  // do not take the alpha channel into account
      if (deltaColor < sigmacolor) {
        // add this to the blur
        this->m_inputColorProgram->read(tempColor, xi, yi, data);
        add_v4_v4(blurColor, tempColor);
        blurDivider += 1.0f;
      }
    }
  }

  if (blurDivider > 0.0f) {
    mul_v4_v4fl(output, blurColor, 1.0f / blurDivider);
  }
  else {
    output[0] = 0.0f;
    output[1] = 0.0f;
    output[2] = 0.0f;
    output[3] = 1.0f;
  }
}

void BilateralBlurOperation::deinitExecution()
{
  this->m_inputColorProgram = nullptr;
  this->m_inputDeterminatorProgram = nullptr;
}

bool BilateralBlurOperation::determineDependingAreaOfInterest(rcti *input,
                                                              ReadBufferOperation *readOperation,
                                                              rcti *output)
{
  rcti newInput;
  int add = ceil(this->m_space) + 1;

  newInput.xmax = input->xmax + (add);
  newInput.xmin = input->xmin - (add);
  newInput.ymax = input->ymax + (add);
  newInput.ymin = input->ymin - (add);

  return NodeOperation::determineDependingAreaOfInterest(&newInput, readOperation, output);
}

}  // namespace blender::compositor