#include "Environment.h"
#include "GvsPreprocessor.h"
#include "GlRenderer.h"
#include "VssRay.h"
#include "ViewCellsManager.h"
#include "Triangle3.h"
#include "IntersectableWrapper.h"


namespace GtpVisibilityPreprocessor
{
  

GvsPreprocessor::GvsPreprocessor(): Preprocessor(), mSamplingType(0)
{
	Environment::GetSingleton()->GetIntValue("GvsPreprocessor.totalSamples", mTotalSamples);
	Environment::GetSingleton()->GetIntValue("GvsPreprocessor.initialSamples", mInitialSamples);
	Environment::GetSingleton()->GetIntValue("GvsPreprocessor.samplesPerPass", mSamplesPerPass);
	Environment::GetSingleton()->GetFloatValue("GvsPreprocessor.epsilon", mEps);
		

	Debug << "Gvs preprocessor options" << endl;
	Debug << "number of total samples: " << mTotalSamples << endl;
	Debug << "number of initial samples: " << mInitialSamples << endl;
	Debug << "number of samples per pass: " << mSamplesPerPass << endl;

	mStats.open("gvspreprocessor.log");
}


const bool GvsPreprocessor::DiscontinuityFound(const VssRay &ray, 
											   const VssRay &oldRay) const
{
    //const Plane3 plane = tri->GetPlane();
	return false;
}


int GvsPreprocessor::HandleRay(const GvsRayInfo &gvsRay)
{
	VssRay *ray = gvsRay.mRay;

	if (!mViewCellsManager->ComputeSampleContribution(*ray, true, false))
		return 1;

	if (gvsRay.mFoundDiscontinuity)
	{
		return ReverseSampling(*ray);
	}
	else
	{
		return AdaptiveBorderSampling(*ray);
	}
}

/** Hepler function for adaptive border sampling. It finds 
	new sample points around a triangle in a eps environment
*/
static void CreateNewSamples(VertexContainer &samples, 
							 const Triangle3 &hitTriangle,
							 const VssRay &ray, 
							 const int index,
							 const float eps)
{
	const int indexU = (index + 1) % 3;
	const int indexL = (index == 0) ? 2 : index - 1;

	const Vector3 a = hitTriangle.mVertices[index] - ray.GetDir();
	const Vector3 b = hitTriangle.mVertices[indexU] - hitTriangle.mVertices[index];
	const Vector3 c = hitTriangle.mVertices[index] - hitTriangle.mVertices[indexL];
	const float len = Magnitude(a);

	// compute the new three hit points
	// pi, i + 1
	const Vector3 dir1 = CrossProd(a, b); //N((pi-xp)×(pi+1- pi));
	const Vector3 pt1 = hitTriangle.mVertices[index] + eps * len * dir1; //pi+ e·|pi-xp|·di, j
	samples.push_back(pt1);

	// pi, i - 1
    const Vector3 dir2 = CrossProd(a, c); // N((pi-xp)×(pi- pi-1))
	const Vector3 pt2 = hitTriangle.mVertices[index] + eps * len * dir2; //pi+ e·|pi-xp|·di, j
	samples.push_back(pt2);

	// pi, i
	const Vector3 dir3 = DotProd(dir1, dir2) > 0 ? 
		Normalize(dir2 + dir1) : Normalize(CrossProd(a, dir2) + CrossProd(dir1, a)); // N((pi-xp)×di,i-1+di,i+1×(pi-xp))
	const Vector3 pt3 = hitTriangle.mVertices[index] + eps * len * dir3; //pi+ e·|pi-xp|·di, j
	samples.push_back(pt3);
}


/** Generate rays from sample points.
*/
static void CreateRays(VssRayContainer &rays,
					   const VertexContainer &samples)
{
	VertexContainer::const_iterator vit, vit_end = samples.end();
	
	for (vit = samples.begin(); vit != vit_end; ++ vit)
	{
		const Vector3 currentSample = *vit;
		VssRay *ray;// = new VssRay(ray->mOrigin, currentSample);
	}
}


int GvsPreprocessor::AdaptiveBorderSampling(const VssRay &prevRay)
{
	cout << "a";
	Intersectable *tObj = prevRay.mTerminationObject;
	Triangle3 hitTriangle;

	// other types not implemented yet
	if (tObj->Type() == Intersectable::TRIANGLE_INTERSECTABLE)
	{
		hitTriangle = dynamic_cast<TriangleIntersectable *>(tObj)->GetItem();
	}

	VertexContainer samples;
	samples.reserve(9);

	CreateNewSamples(samples, hitTriangle, prevRay, 0, mEps);
	CreateNewSamples(samples, hitTriangle, prevRay, 1, mEps);
	CreateNewSamples(samples, hitTriangle, prevRay, 2, mEps);

	VssRayContainer vssRays;
	CreateRays(vssRays, samples);

	VssRayContainer::const_iterator rit, rit_end = vssRays.end();
	
	for (rit = vssRays.begin(); rit != rit_end; ++ rit)
	{
		VssRay *ray = *rit;

		// discontinuity found? 
		// schedule for reverse sampling or adaptive border sampling
		const bool gap = DiscontinuityFound(*ray, prevRay);
		mRayQueue.push(GvsRayInfo(ray, gap));
	}

	return 9;
}


int GvsPreprocessor::ReverseSampling(const VssRay &ray)
{
	cout << "r" << endl;
	// TODO
	return 1;
}


int GvsPreprocessor::CastInitialSamples(const int numSamples, 
										const int sampleType)
{	
	const long startTime = GetTime();

	// generate simple rays
	SimpleRayContainer simpleRays;
	GenerateRays(numSamples, sampleType, simpleRays);
	
	// generate vss rays
	VssRayContainer samples;
	CastRays(simpleRays, samples);
	
	// add to ray queue
	EnqueueSamples(samples);

	Debug << "generated " <<  numSamples << " samples in " << TimeDiff(startTime, GetTime()) * 1e-3 << " secs" << endl;

	return (int)samples.size();
}


void GvsPreprocessor::EnqueueSamples(VssRayContainer &samples, VssRay *oldRay)
{
	// add samples to ray queue
	VssRayContainer::const_iterator vit, vit_end = samples.end();
	for (vit = samples.begin(); vit != vit_end; ++ vit)
	{
		/// if there is no old ray, no discontinuity
		const bool gap = oldRay ? DiscontinuityFound(*(*vit), *oldRay) : false;
		mRayQueue.push(GvsRayInfo(*vit, gap));
	}

}


int GvsPreprocessor::Pass()
{
	int castSamples = 0;
	const int mSampleType = 0;
	while (castSamples < mSamplesPerPass) 
	{
		// Ray queue empty => 
		// cast a number of uniform samples to fill ray Queue
		CastInitialSamples(mInitialSamples, mSampleType);

		const int gvsSamples = ProcessQueue();
		castSamples += gvsSamples;
		//cout << "\ncast " << castSamples << " of " << mSamplesPerPass << endl;
	}

	return castSamples;
}


int GvsPreprocessor::ProcessQueue()
{
	int castSamples = 0;

	while (!mRayQueue.empty()) 
	{
		// handle next ray
		GvsRayInfo rayInfo = mRayQueue.top();
		mRayQueue.pop();
		
		castSamples += HandleRay(rayInfo);
	}

	return castSamples;
}


bool GvsPreprocessor::ComputeVisibility()
{
	Randomize(0);
	const long startTime = GetTime();
	
	mViewSpaceBox = mKdTree->GetBox();
	cout << "Gvs Preprocessor started\n" << flush;
	
	if (!mLoadViewCells)
	{	/// construct the view cells from the scratch
		ConstructViewCells(mViewSpaceBox);
		cout << "view cells loaded" << endl;
	}

	int castSamples = 0;

	while (castSamples < mTotalSamples) 
	{
		const int passSamples = Pass();
		castSamples += passSamples;
		
		/////////////
		// -- stats
		cout << "+";
		cout << "\nsamples cast " << passSamples << " (=" << castSamples << " of " << mTotalSamples << ")" << endl;
		//mVssRays.PrintStatistics(mStats);
		mStats << "#Time\n" << TimeDiff(startTime, GetTime())*1e-3 << endl
			   << "#TotalSamples\n" << castSamples << endl;

		mViewCellsManager->PrintPvsStatistics(mStats);
		// ComputeRenderError();
	}

	return true;
}

}