/*
-----------------------------------------------------------------------
Copyright: 2010-2016, iMinds-Vision Lab, University of Antwerp
           2014-2016, CWI, Amsterdam

Contact: astra@uantwerpen.be
Website: http://www.astra-toolbox.com/

This file is part of the ASTRA Toolbox.


The ASTRA Toolbox 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.

The ASTRA Toolbox 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 the ASTRA Toolbox. If not, see <http://www.gnu.org/licenses/>.

-----------------------------------------------------------------------
*/

#include "astra/ParallelBeamLinearKernelProjector2D.h"

#include <cmath>
#include <algorithm>

#include "astra/DataProjectorPolicies.h"

using namespace std;
using namespace astra;

#include "astra/ParallelBeamLinearKernelProjector2D.inl"

// type of the projector, needed to register with CProjectorFactory
std::string CParallelBeamLinearKernelProjector2D::type = "linear";

//----------------------------------------------------------------------------------------
// default constructor
CParallelBeamLinearKernelProjector2D::CParallelBeamLinearKernelProjector2D()
{
	_clear();
}


//----------------------------------------------------------------------------------------
// constructor
CParallelBeamLinearKernelProjector2D::CParallelBeamLinearKernelProjector2D(CParallelProjectionGeometry2D* _pProjectionGeometry,
																		   CVolumeGeometry2D* _pReconstructionGeometry)

{
	_clear();
	initialize(_pProjectionGeometry, _pReconstructionGeometry);
}

//----------------------------------------------------------------------------------------
// destructor
CParallelBeamLinearKernelProjector2D::~CParallelBeamLinearKernelProjector2D()
{
	clear();
}

//---------------------------------------------------------------------------------------
// Clear - CParallelBeamLinearKernelProjector2D
void CParallelBeamLinearKernelProjector2D::_clear()
{
	CProjector2D::_clear();
	m_bIsInitialized = false;
}

//---------------------------------------------------------------------------------------
// Clear - Public
void CParallelBeamLinearKernelProjector2D::clear()
{
	CProjector2D::clear();
	m_bIsInitialized = false;
}

//---------------------------------------------------------------------------------------
// Check
bool CParallelBeamLinearKernelProjector2D::_check()
{
	// check base class
	ASTRA_CONFIG_CHECK(CProjector2D::_check(), "ParallelBeamLinearKernelProjector2D", "Error in Projector2D initialization");

	ASTRA_CONFIG_CHECK(dynamic_cast<CParallelProjectionGeometry2D*>(m_pProjectionGeometry), "ParallelBeamLinearKernelProjector2D", "Unsupported projection geometry");

	/// TODO: ADD PIXEL H/W LIMITATIONS
	ASTRA_CONFIG_CHECK(m_pVolumeGeometry->getPixelLengthX() == m_pVolumeGeometry->getPixelLengthY(), "ParallelBeamLinearKernelProjector2D", "Pixel height must equal pixel width.");

	// success
	return true;
}

//---------------------------------------------------------------------------------------
// Initialize, use a Config object
bool CParallelBeamLinearKernelProjector2D::initialize(const Config& _cfg)
{
	ASTRA_ASSERT(_cfg.self);

	// if already initialized, clear first
	if (m_bIsInitialized) {
		clear();
	}

	// initialization of parent class
	if (!CProjector2D::initialize(_cfg)) {
		return false;
	}

	// success
	m_bIsInitialized = _check();
	return m_bIsInitialized;
}

//---------------------------------------------------------------------------------------
// Initialize
bool CParallelBeamLinearKernelProjector2D::initialize(CParallelProjectionGeometry2D* _pProjectionGeometry, 
													  CVolumeGeometry2D* _pVolumeGeometry)
{
	// if already initialized, clear first
	if (m_bIsInitialized) {
		clear();
	}

	// hardcopy geometries
	m_pProjectionGeometry = _pProjectionGeometry->clone();
	m_pVolumeGeometry = _pVolumeGeometry->clone();

	// success
	m_bIsInitialized = _check();
	return m_bIsInitialized;
}

//----------------------------------------------------------------------------------------
// Get maximum amount of weights on a single ray
int CParallelBeamLinearKernelProjector2D::getProjectionWeightsCount(int _iProjectionIndex)
{
	int maxDim = max(m_pVolumeGeometry->getGridRowCount(), m_pVolumeGeometry->getGridColCount());
	return maxDim * 2 + 1;
}

//----------------------------------------------------------------------------------------
// Single Ray Weights
void CParallelBeamLinearKernelProjector2D::computeSingleRayWeights(int _iProjectionIndex, 
														   int _iDetectorIndex, 
														   SPixelWeight* _pWeightedPixels,
														   int _iMaxPixelCount, 
														   int& _iStoredPixelCount)
{
	ASTRA_ASSERT(m_bIsInitialized);
	StorePixelWeightsPolicy p(_pWeightedPixels, _iMaxPixelCount);
	projectSingleRay(_iProjectionIndex, _iDetectorIndex, p);
	_iStoredPixelCount = p.getStoredPixelCount();
}

//----------------------------------------------------------------------------------------
// Splat a single point
std::vector<SDetector2D> CParallelBeamLinearKernelProjector2D::projectPoint(int _iRow, int _iCol)
{
	float32 xUL = m_pVolumeGeometry->pixelColToCenterX(_iCol) - m_pVolumeGeometry->getPixelLengthX() * 1.5f;
	float32 yUL = m_pVolumeGeometry->pixelRowToCenterY(_iRow) - m_pVolumeGeometry->getPixelLengthY() * 1.5f;
	float32 xUR = m_pVolumeGeometry->pixelColToCenterX(_iCol) + m_pVolumeGeometry->getPixelLengthX() * 1.5f;
	float32 yUR = m_pVolumeGeometry->pixelRowToCenterY(_iRow) - m_pVolumeGeometry->getPixelLengthY() * 1.5f;
	float32 xLL = m_pVolumeGeometry->pixelColToCenterX(_iCol) - m_pVolumeGeometry->getPixelLengthX() * 1.5f;
	float32 yLL = m_pVolumeGeometry->pixelRowToCenterY(_iRow) + m_pVolumeGeometry->getPixelLengthY() * 1.5f;
	float32 xLR = m_pVolumeGeometry->pixelColToCenterX(_iCol) + m_pVolumeGeometry->getPixelLengthX() * 1.5f;
	float32 yLR = m_pVolumeGeometry->pixelRowToCenterY(_iRow) + m_pVolumeGeometry->getPixelLengthY() * 1.5f;

	std::vector<SDetector2D> res;
	// loop projectors and detectors
	for (int iProjection = 0; iProjection < m_pProjectionGeometry->getProjectionAngleCount(); ++iProjection) {

		// get projection angle
		float32 theta = m_pProjectionGeometry->getProjectionAngle(iProjection);
		if (theta >= 7*PIdiv4) theta -= 2*PI;
		bool inverse = false;
		if (theta >= 3*PIdiv4) {
			theta -= PI;
			inverse = true;
		}

		// calculate distance from the center of the voxel to the ray though the origin
		float32 tUL = xUL * cos(theta) + yUL * sin(theta);
		float32 tUR = xUR * cos(theta) + yUR * sin(theta);
		float32 tLL = xLL * cos(theta) + yLL * sin(theta);
		float32 tLR = xLR * cos(theta) + yLR * sin(theta);
		if (inverse) {
			tUL *= -1.0f;
			tUR *= -1.0f;
			tLL *= -1.0f;
			tLR *= -1.0f;
		}
		float32 tMin = min(tUL, min(tUR, min(tLL,tLR)));
		float32 tMax = max(tUL, max(tUR, max(tLL,tLR)));

		// calculate the offset on the detectorarray (in indices)
		int dmin = (int)floor(m_pProjectionGeometry->detectorOffsetToIndexFloat(tMin));
		int dmax = (int)ceil(m_pProjectionGeometry->detectorOffsetToIndexFloat(tMax));

		// add affected detectors to the list
		for (int i = dmin; i <= dmax; ++i) {
			if (i >= 0 && i < m_pProjectionGeometry->getDetectorCount()) {
				SDetector2D det;
				det.m_iAngleIndex = iProjection;
				det.m_iDetectorIndex = i;
				det.m_iIndex = iProjection * getProjectionGeometry()->getDetectorCount() + i;
				res.push_back(det);
			}
		}
	}

	// return result vector
	return res;

}