// Aseprite
// Copyright (C) 2017  David Capello
//
// This program is distributed under the terms of
// the End-User License Agreement for Aseprite.

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "filters/brightness_contrast_filter.h"

#include "doc/image.h"
#include "doc/palette.h"
#include "doc/rgbmap.h"
#include "filters/filter_indexed_data.h"
#include "filters/filter_manager.h"
#include "gfx/hsl.h"
#include "gfx/rgb.h"

#include <cmath>

namespace filters {

using namespace doc;

const char* BrightnessContrastFilter::getName()
{
  return "Brightness Contrast";
}

BrightnessContrastFilter::BrightnessContrastFilter()
  : m_brightness(0.0)
  , m_contrast(0.0)
  , m_cmap(256)
{
  updateMap();
}

void BrightnessContrastFilter::setBrightness(double brightness)
{
  m_brightness = brightness;
  updateMap();
}

void BrightnessContrastFilter::setContrast(double contrast)
{
  m_contrast = contrast;
  updateMap();
}

void BrightnessContrastFilter::applyToRgba(FilterManager* filterMgr)
{
  FilterIndexedData* fid = filterMgr->getIndexedData();

  if (filterMgr->isFirstRow()) {
    m_picks = fid->getPalettePicks();
    m_usePalette = (m_picks.picks() > 0);
    if (m_usePalette)
      applyToPalette(filterMgr);
  }

  const Palette* pal = fid->getPalette();
  const uint32_t* src_address = (uint32_t*)filterMgr->getSourceAddress();
  uint32_t* dst_address = (uint32_t*)filterMgr->getDestinationAddress();
  const int w = filterMgr->getWidth();
  const Target target = filterMgr->getTarget();

  for (int x=0; x<w; x++) {
    if (filterMgr->skipPixel()) {
      ++src_address;
      ++dst_address;
      continue;
    }

    color_t c = *(src_address++);

    if (m_usePalette) {
      int i =
        pal->findExactMatch(rgba_getr(c),
                            rgba_getg(c),
                            rgba_getb(c),
                            rgba_geta(c), -1);
      if (i >= 0)
        c = fid->getNewPalette()->getEntry(i);
    }
    else {
      applyFilterToRgb(target, c);
    }

    *(dst_address++) = c;
  }
}

void BrightnessContrastFilter::applyToGrayscale(FilterManager* filterMgr)
{
  const uint16_t* src_address = (uint16_t*)filterMgr->getSourceAddress();
  uint16_t* dst_address = (uint16_t*)filterMgr->getDestinationAddress();
  const int w = filterMgr->getWidth();
  const Target target = filterMgr->getTarget();

  for (int x=0; x<w; x++) {
    if (filterMgr->skipPixel()) {
      ++src_address;
      ++dst_address;
      continue;
    }

    color_t c = *(src_address++);
    int k = graya_getv(c);
    int a = graya_geta(c);

    if (target & TARGET_GRAY_CHANNEL) k = m_cmap[k];

    *(dst_address++) = graya(k, a);
  }
}

void BrightnessContrastFilter::applyToIndexed(FilterManager* filterMgr)
{
  FilterIndexedData* fid = filterMgr->getIndexedData();

  // Apply filter to color palette if there is no selection
  if (!filterMgr->isMaskActive()) {
    if (!filterMgr->isFirstRow())
      return;

    m_picks = fid->getPalettePicks();
    if (m_picks.picks() == 0)
      m_picks.all();

    applyToPalette(filterMgr);
    return;
  }

  // Apply filter to color region
  const Target target = filterMgr->getTarget();
  const Palette* pal = fid->getPalette();
  const RgbMap* rgbmap = fid->getRgbMap();
  const uint8_t* src_address = (uint8_t*)filterMgr->getSourceAddress();
  uint8_t* dst_address = (uint8_t*)filterMgr->getDestinationAddress();
  const int w = filterMgr->getWidth();

  for (int x=0; x<w; x++) {
    if (filterMgr->skipPixel()) {
      ++src_address;
      ++dst_address;
      continue;
    }

    color_t c = pal->getEntry(*(src_address++));
    applyFilterToRgb(target, c);
    *(dst_address++) = rgbmap->mapColor(rgba_getr(c),
                                        rgba_getg(c),
                                        rgba_getb(c),
                                        rgba_geta(c));
  }
}

void BrightnessContrastFilter::applyToPalette(FilterManager* filterMgr)
{
  const Target target = filterMgr->getTarget();
  FilterIndexedData* fid = filterMgr->getIndexedData();
  const Palette* pal = fid->getPalette();
  Palette* newPal = fid->getNewPalette();

  int i = 0;
  for (bool state : m_picks) {
    if (!state) {
      ++i;
      continue;
    }

    color_t c = pal->getEntry(i);
    applyFilterToRgb(target, c);
    newPal->setEntry(i, c);
    ++i;
  }
}

void BrightnessContrastFilter::applyFilterToRgb(
  const Target target, doc::color_t& c)
{
  int r = rgba_getr(c);
  int g = rgba_getg(c);
  int b = rgba_getb(c);
  int a = rgba_geta(c);

  if (target & TARGET_RED_CHANNEL  ) r = m_cmap[r];
  if (target & TARGET_GREEN_CHANNEL) g = m_cmap[g];
  if (target & TARGET_BLUE_CHANNEL ) b = m_cmap[b];

  c = rgba(r, g, b, a);
}

void BrightnessContrastFilter::updateMap()
{
  int max = int(m_cmap.size());
  for (int u=0; u<max; ++u) {
    double x = double(u) / double(max-1);
    double y = (m_contrast+1.0) * (x - 0.5) + 0.5;
    y = y*(1.0+m_brightness);
    y = MID(0.0, y, 1.0);
    m_cmap[u] = int(255.5 * y);
  }
}

} // namespace filters
