/*
 * Copyright 2011, Blender Foundation.
 *
 * 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.
 *
 * Contributor:
 *      Jeroen Bakker
 *      Monique Dewanchand
 */

#include "COM_ColorCorrectionOperation.h"
#include "BLI_math.h"

extern "C" {
#include "IMB_colormanagement.h"
}

ColorCorrectionOperation::ColorCorrectionOperation() : NodeOperation()
{
	this->addInputSocket(COM_DT_COLOR);
	this->addInputSocket(COM_DT_VALUE);
	this->addOutputSocket(COM_DT_COLOR);
	this->m_inputImage = NULL;
	this->m_inputMask = NULL;
	this->m_redChannelEnabled = true;
	this->m_greenChannelEnabled = true;
	this->m_blueChannelEnabled = true;
}
void ColorCorrectionOperation::initExecution()
{
	this->m_inputImage = this->getInputSocketReader(0);
	this->m_inputMask = this->getInputSocketReader(1);
}

void ColorCorrectionOperation::executePixelSampled(float output[4], float x, float y, PixelSampler sampler)
{
	float inputImageColor[4];
	float inputMask[4];
	this->m_inputImage->readSampled(inputImageColor, x, y, sampler);
	this->m_inputMask->readSampled(inputMask, x, y, sampler);

	float level = (inputImageColor[0] + inputImageColor[1] + inputImageColor[2]) / 3.0f;
	float contrast = this->m_data->master.contrast;
	float saturation = this->m_data->master.saturation;
	float gamma = this->m_data->master.gamma;
	float gain = this->m_data->master.gain;
	float lift = this->m_data->master.lift;
	float r, g, b;

	float value = inputMask[0];
	value = min(1.0f, value);
	const float mvalue = 1.0f - value;

	float levelShadows = 0.0;
	float levelMidtones = 0.0;
	float levelHighlights = 0.0;
#define MARGIN 0.10f
#define MARGIN_DIV (0.5f / MARGIN)
	if (level < this->m_data->startmidtones - MARGIN) {
		levelShadows = 1.0f;
	}
	else if (level < this->m_data->startmidtones + MARGIN) {
		levelMidtones = ((level - this->m_data->startmidtones) * MARGIN_DIV) + 0.5f;
		levelShadows = 1.0f - levelMidtones;
	}
	else if (level < this->m_data->endmidtones - MARGIN) {
		levelMidtones = 1.0f;
	}
	else if (level < this->m_data->endmidtones + MARGIN) {
		levelHighlights = ((level - this->m_data->endmidtones) * MARGIN_DIV) + 0.5f;
		levelMidtones = 1.0f - levelHighlights;
	}
	else {
		levelHighlights = 1.0f;
	}
#undef MARGIN
#undef MARGIN_DIV
	contrast *= (levelShadows * this->m_data->shadows.contrast) + (levelMidtones * this->m_data->midtones.contrast) + (levelHighlights * this->m_data->highlights.contrast);
	saturation *= (levelShadows * this->m_data->shadows.saturation) + (levelMidtones * this->m_data->midtones.saturation) + (levelHighlights * this->m_data->highlights.saturation);
	gamma *= (levelShadows * this->m_data->shadows.gamma) + (levelMidtones * this->m_data->midtones.gamma) + (levelHighlights * this->m_data->highlights.gamma);
	gain *= (levelShadows * this->m_data->shadows.gain) + (levelMidtones * this->m_data->midtones.gain) + (levelHighlights * this->m_data->highlights.gain);
	lift += (levelShadows * this->m_data->shadows.lift) + (levelMidtones * this->m_data->midtones.lift) + (levelHighlights * this->m_data->highlights.lift);

	float invgamma = 1.0f / gamma;
	float luma = IMB_colormanagement_get_luminance(inputImageColor);

	r = inputImageColor[0];
	g = inputImageColor[1];
	b = inputImageColor[2];

	r = (luma + saturation * (r - luma));
	g = (luma + saturation * (g - luma));
	b = (luma + saturation * (b - luma));

	r = 0.5f + ((r - 0.5f) * contrast);
	g = 0.5f + ((g - 0.5f) * contrast);
	b = 0.5f + ((b - 0.5f) * contrast);

	r = powf(r * gain + lift, invgamma);
	g = powf(g * gain + lift, invgamma);
	b = powf(b * gain + lift, invgamma);


	// mix with mask
	r = mvalue * inputImageColor[0] + value * r;
	g = mvalue * inputImageColor[1] + value * g;
	b = mvalue * inputImageColor[2] + value * b;

	if (this->m_redChannelEnabled) {
		output[0] = r;
	}
	else {
		output[0] = inputImageColor[0];
	}
	if (this->m_greenChannelEnabled) {
		output[1] = g;
	}
	else {
		output[1] = inputImageColor[1];
	}
	if (this->m_blueChannelEnabled) {
		output[2] = b;
	}
	else {
		output[2] = inputImageColor[2];
	}
	output[3] = inputImageColor[3];
}

void ColorCorrectionOperation::deinitExecution()
{
	this->m_inputImage = NULL;
	this->m_inputMask = NULL;
}