#include "SceneGraph.h"
#include "KdTree.h"
#include "VssPreprocessor.h"
#include "X3dExporter.h"
#include "Environment.h"
#include "MutualVisibility.h"
#include "Polygon3.h"
#include "ViewCell.h"
#include "VssRay.h"
#include "VssTree.h"
#include "ViewCellsManager.h"
#include "RenderSimulator.h"
#include "Beam.h"
#include "GlRenderer.h"

bool use2dSampling = false;
bool useViewspacePlane = false;

VssPreprocessor::VssPreprocessor():
  mPass(0),
  mVssRays()
{
  // this should increase coherence of the samples
  environment->GetIntValue("VssPreprocessor.samplesPerPass", mSamplesPerPass);
  environment->GetIntValue("VssPreprocessor.initialSamples", mInitialSamples);
  environment->GetIntValue("VssPreprocessor.vssSamples", mVssSamples);
  environment->GetIntValue("VssPreprocessor.vssSamplesPerPass", mVssSamplesPerPass);
  environment->GetBoolValue("VssPreprocessor.useImportanceSampling", mUseImportanceSampling);
  environment->GetBoolValue("ViewCells.delayedConstruction", mDelayedViewCellsConstruction);

  environment->GetBoolValue("VssPreprocessor.loadInitialSamples", mLoadInitialSamples);
  environment->GetBoolValue("VssPreprocessor.storeInitialSamples", mStoreInitialSamples);
  environment->GetBoolValue("VssPreprocessor.useViewSpaceBox", mUseViewSpaceBox);
  environment->GetBoolValue("VssPreprocessor.testBeamSampling", mTestBeamSampling);

  useViewspacePlane = mUseViewSpaceBox; //hack

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

VssPreprocessor::~VssPreprocessor()
{
  CLEAR_CONTAINER(mVssRays);
}

void
VssPreprocessor::SetupRay(Ray &ray,
						  const Vector3 &point,
						  const Vector3 &direction
						  )
{
  ray.Clear();
  // do not store anything else then intersections at the ray
  ray.Init(point, direction, Ray::LOCAL_RAY);
}

int
VssPreprocessor::CastRay(
						 Vector3 &viewPoint,
						 Vector3 &direction,
						 VssRayContainer &vssRays
						 )
{

    int hits = 0;
  static Ray ray;
  AxisAlignedBox3 box = mKdTree->GetBox();

  AxisAlignedBox3 sbox = box;
  sbox.Enlarge(Vector3(-Limits::Small));
  if (!sbox.IsInside(viewPoint))
	return 0;
	
  SetupRay(ray, viewPoint, direction);
  // cast ray to KD tree to find intersection with other objects
  Intersectable *objectA, *objectB;
  Vector3 pointA, pointB;
  float bsize = Magnitude(box.Size());


  if (!mDetectEmptyViewSpace)
	ray.mFlags &= ~Ray::CULL_BACKFACES;
  
  if (mKdTree->CastRay(ray)) {
	objectA = ray.intersections[0].mObject;
	pointA = ray.Extrap(ray.intersections[0].mT);
  } else {
	objectA = NULL;
	// compute intersection with the scene bounding box
	float tmin, tmax;
	if (box.ComputeMinMaxT(ray, &tmin, &tmax) && tmin < tmax)
	  pointA = ray.Extrap(tmax);
	else
	  return 0;
  }

	
  if (mDetectEmptyViewSpace) {
	SetupRay(ray, pointA, -direction);
  } else
	SetupRay(ray, viewPoint, -direction);
  
  if (!mDetectEmptyViewSpace)
	ray.mFlags &= ~Ray::CULL_BACKFACES;

  if (mKdTree->CastRay(ray)) {
	objectB = ray.intersections[0].mObject;
	pointB = ray.Extrap(ray.intersections[0].mT);
  } else {
	objectB = NULL;
	float tmin, tmax;
	if (box.ComputeMinMaxT(ray, &tmin, &tmax) && tmin < tmax)
	  pointB = ray.Extrap(tmax);
	else
	  return 0;
  }
  
  //  if (objectA == NULL && objectB != NULL) {
  if (mDetectEmptyViewSpace) {
	// cast again to ensure that there is no objectA
	SetupRay(ray, pointB, direction);
	if (mKdTree->CastRay(ray)) {
	  objectA = ray.intersections[0].mObject;
	  pointA = ray.Extrap(ray.intersections[0].mT);
	}
  }

  
  VssRay *vssRay  = NULL;

  bool validSample = (objectA != objectB);
  if (0 && mDetectEmptyViewSpace) {   // consider all samples valid
	// check if the viewpoint lies on the line segment AB
	if (Distance(pointA, pointB) <
		Distance(viewPoint, pointA) + Distance(viewPoint, pointB) - Limits::Small) {
	  validSample = false;
	}
  }
	
  if (validSample) {
	if (objectA) {
	  vssRay = new VssRay(pointB,
						  pointA,
						  objectB,
						  objectA,
						  mPass
						  );
	  vssRays.push_back(vssRay);
	  hits ++;
	}
	
	if (objectB) {
	  vssRay = new VssRay(pointA,
						  pointB,
						  objectA,
						  objectB,
						  mPass
						  );
	  vssRays.push_back(vssRay);
	  hits ++;
	}
  }
	
  return hits;
}


Vector3
VssPreprocessor::GetViewpoint(AxisAlignedBox3 *viewSpaceBox)
{
  AxisAlignedBox3 box;

  if (viewSpaceBox)
	box =*viewSpaceBox;
  else
	box = mKdTree->GetBox();

  // shrink the box in the y direction
  return box.GetRandomPoint();
}

Vector3
VssPreprocessor::GetDirection(const Vector3 &viewpoint,
							  AxisAlignedBox3 *viewSpaceBox
							  )
{
  Vector3 point;
  if (!use2dSampling) {
	if (0) {
	  Vector3 normal;
	  int i = Random((int)mObjects.size());
	  Intersectable *object = mObjects[i];
	  object->GetRandomSurfacePoint(point, normal);
	} else
	  point = mKdTree->GetBox().GetRandomPoint();
	//	  point = viewpoint + UniformRandomVector();

  } else {
	AxisAlignedBox3 box;

	if (viewSpaceBox)
	  box =*viewSpaceBox;
	else
	  box = mKdTree->GetBox();

	point = box.GetRandomPoint();
	point.y = viewpoint.y;
  }

  return point - viewpoint;
}

int
VssPreprocessor::GenerateImportanceRays(VssTree *vssTree,
										const int desiredSamples,
										SimpleRayContainer &rays
										)
{
  int num;
  if (0) {
	float minRayContribution;
	float maxRayContribution;
	float avgRayContribution;

	vssTree->GetRayContributionStatistics(minRayContribution,
										  maxRayContribution,
										  avgRayContribution);

	cout<<
	  "#MIN_RAY_CONTRIB\n"<<minRayContribution<<endl<<
	  "#MAX_RAY_CONTRIB\n"<<maxRayContribution<<endl<<
	  "#AVG_RAY_CONTRIB\n"<<avgRayContribution<<endl;

	float p = desiredSamples/(float)(avgRayContribution*vssTree->stat.Leaves());
	num = vssTree->GenerateRays(p, rays);
  } else {
	int leaves = vssTree->stat.Leaves();
	num = vssTree->GenerateRays(desiredSamples, leaves, rays);
  }

  cout<<"Generated "<<num<<" rays."<<endl;

  return num;
}


bool
VssPreprocessor::ExportRays(const char *filename,
							const VssRayContainer &vssRays,
							const int number
							)
{
  cout<<"Exporting vss rays..."<<endl<<flush;

  Exporter *exporter = NULL;
  exporter = Exporter::GetExporter(filename);
  //	exporter->SetWireframe();
  //	exporter->ExportKdTree(*mKdTree);
  exporter->SetFilled();
  exporter->ExportScene(mSceneGraph->mRoot);
  exporter->SetWireframe();

  if (mViewSpaceBox) {
	exporter->SetForcedMaterial(RgbColor(1,0,1));
	exporter->ExportBox(*mViewSpaceBox);
	exporter->ResetForcedMaterial();
  }

  VssRayContainer rays;
  vssRays.SelectRays(number, rays);
  
  exporter->ExportRays(rays, RgbColor(1, 0, 0));

  delete exporter;

  cout<<"done."<<endl<<flush;

  return true;
}


bool
VssPreprocessor::ExportVssTree(char *filename,
							   VssTree *tree,
							   const Vector3 &dir
							   )
{
  Exporter *exporter = Exporter::GetExporter(filename);
  exporter->SetFilled();
  exporter->ExportScene(mSceneGraph->mRoot);
  //  exporter->SetWireframe();
  bool result = exporter->ExportVssTree2( *tree, dir );
  delete exporter;
  return result;
}

bool
VssPreprocessor::ExportVssTreeLeaf(char *filename,
								   VssTree *tree,
								   VssTreeLeaf *leaf)
{
  Exporter *exporter = NULL;
  exporter = Exporter::GetExporter(filename);
  exporter->SetWireframe();
  exporter->ExportKdTree(*mKdTree);

  if (mViewSpaceBox) {
	exporter->SetForcedMaterial(RgbColor(1,0,0));
	exporter->ExportBox(*mViewSpaceBox);
	exporter->ResetForcedMaterial();
  }

  exporter->SetForcedMaterial(RgbColor(0,0,1));
  exporter->ExportBox(tree->GetBBox(leaf));
  exporter->ResetForcedMaterial();

  VssRayContainer rays[4];
  for (int i=0; i < leaf->rays.size(); i++) {
	int k = leaf->rays[i].GetRayClass();
	rays[k].push_back(leaf->rays[i].mRay);
  }

  // SOURCE RAY
  exporter->ExportRays(rays[0], RgbColor(1, 0, 0));
  // TERMINATION RAY
  exporter->ExportRays(rays[1], RgbColor(1, 1, 1));
  // PASSING_RAY
  exporter->ExportRays(rays[2], RgbColor(1, 1, 0));
  // CONTAINED_RAY
  exporter->ExportRays(rays[3], RgbColor(0, 0, 1));

  delete exporter;
  return true;
}

void
VssPreprocessor::ExportVssTreeLeaves(VssTree *tree, const int number)
{
  vector<VssTreeLeaf *> leaves;
  tree->CollectLeaves(leaves);

  int num = 0;
  int i;
  float p = number / (float)leaves.size();
  for (i=0; i < leaves.size(); i++) {
	if (RandomValue(0,1) < p) {
	  char filename[64];
	  sprintf(filename, "vss-leaf-%04d.x3d", num);
	  ExportVssTreeLeaf(filename, tree, leaves[i]);
	  num++;
	}
	if (num >= number)
	  break;
  }
}


void VssPreprocessor::TestBeamCasting(VssTree *tree, ViewCellsManager *vm)
{
	vector<VssTreeLeaf *> leaves;
	tree->CollectLeaves(leaves);

	for (int i = 0; i < 10; ++i)
	{
		const int index = (int)RandomValue(0, (Real)((int)leaves.size() - 1));
		VssTreeLeaf *leaf = leaves[index];

		Beam beam;
		AxisAlignedBox3 dirBox =tree->GetDirBBox(leaf);
		AxisAlignedBox3 box = tree->GetBBox(leaf);
		
		beam.Construct(dirBox, box);

		// collect kd leaves and view cells
		mKdTree->CastBeam(beam);
		vm->CastBeam(beam);

		Debug << "found " << beam.mViewCells.size() << " view cells and " 
			  << beam.mKdNodes.size() << " kd nodes" << endl;

		Intersectable *sourceObj = mObjects[5];
		BeamSampleStatistics stats;
		renderer->SampleBeamContributions(sourceObj,
										  beam,
										  10000,
										  stats);

		Debug << "beam statistics: " << stats << endl << endl;
	}

}

float
VssPreprocessor::GetAvgPvsSize(VssTree *tree,
							   const vector<AxisAlignedBox3> &viewcells
							   )
{
  vector<AxisAlignedBox3>::const_iterator it, it_end = viewcells.end();

  int sum = 0;
  for (it = viewcells.begin(); it != it_end; ++ it)
	sum += tree->GetPvsSize(*it);

  return sum/(float)viewcells.size();
}

bool
VssPreprocessor::ComputeVisibility()
{


  long startTime = GetTime();

  int totalSamples = 0;


  AxisAlignedBox3 *box = new AxisAlignedBox3(mKdTree->GetBox());
  
  if (!useViewspacePlane) {
	float size = 0.05f;
	float s = 0.5f - size;
	float olds = Magnitude(box->Size());
	box->Enlarge(box->Size()*Vector3(-s));
	Vector3 translation = Vector3(-olds*0.1f, 0, 0);
	box->SetMin(box->Min() + translation);
	box->SetMax(box->Max() + translation);
  } else {

	// sample city like heights
	box->SetMin(1, box->Min(1) + box->Size(1)*0.2f);
	box->SetMax(1, box->Min(1) + box->Size(1)*0.3f);
  }

  if (use2dSampling)
	box->SetMax(1, box->Min(1));

  cout<<"mUseViewSpaceBox="<<mUseViewSpaceBox<<endl;
  if (mUseViewSpaceBox)
  {
	mViewSpaceBox = box;
	mViewCellsManager->SetViewSpaceBox(*box);
  }
  else
  {
	mViewSpaceBox = NULL;
	mViewCellsManager->SetViewSpaceBox(mKdTree->GetBox());
  }
  
  //-- load view cells from file if requested
  if (mLoadViewCells)
  {	
	  // load now because otherwise bounding box not correct
	  mViewCellsManager->LoadViewCells(mViewCellsFilename, &mObjects);
  }


  VssTree *vssTree = NULL;

  mSceneGraph->CollectObjects(&mObjects);

  long initialTime = GetTime();

  if (mLoadInitialSamples)
  {
	  cout << "Loading samples from file ... ";
	  LoadSamples(mVssRays, mObjects);
	  cout << "finished\n" << endl;
	  totalSamples = (int)mVssRays.size();
  }
  else
  {
	
	while (totalSamples < mInitialSamples) {
		int passContributingSamples = 0;
		int passSampleContributions = 0;
		int passSamples = 0;

		int index = 0;

		int sampleContributions;

		int s = Min(mSamplesPerPass, mInitialSamples);
		for (int k=0; k < s; k++) {
			// changed by matt
			Vector3 viewpoint; 
			//			viewpoint = GetViewpoint(mViewSpaceBox);
			mViewCellsManager->GetViewPoint(viewpoint);
			Vector3 direction = GetDirection(viewpoint, mViewSpaceBox);

			sampleContributions = CastRay(viewpoint, direction, mVssRays);

			if (sampleContributions) {
				passContributingSamples ++;
				passSampleContributions += sampleContributions;
			}
			passSamples++;
			totalSamples++;
		}

		mPass++;
		int pvsSize = 0;
		float avgRayContrib = (passContributingSamples > 0) ?
			passSampleContributions/(float)passContributingSamples : 0;

		cout << "#Pass " << mPass << " : t = " << TimeDiff(startTime, GetTime())*1e-3 << "s" << endl;
		cout << "#TotalSamples=" << totalSamples/1000
			<< "k   #SampleContributions=" << passSampleContributions << " ("
			<< 100*passContributingSamples/(float)passSamples<<"%)" << " avgPVS="
			<< pvsSize/(float)mObjects.size() << endl
			<< "avg ray contrib=" << avgRayContrib << endl;

		mStats <<
			"#Pass\n" <<mPass<<endl<<
			"#Time\n" << TimeDiff(startTime, GetTime())*1e-3 << endl<<
			"#TotalSamples\n" << totalSamples<< endl<<
			"#SampleContributions\n" << passSampleContributions << endl <<
			"#PContributingSamples\n"<<100*passContributingSamples/(float)passSamples<<endl <<
			"#AvgPVS\n"<< pvsSize/(float)mObjects.size() << endl <<
			"#AvgRayContrib\n" << avgRayContrib << endl;
	  }
 
	  cout << "#totalPvsSize=" << mKdTree->CollectLeafPvs() << endl;


	  
  }
  
  cout << "#totalRayStackSize=" << (int)mVssRays.size() << endl << flush;
  Debug << (int)mVssRays.size() << " rays generated in " 
	    << TimeDiff(initialTime, GetTime()) * 1e-3 << " seconds" << endl;

  if (mStoreInitialSamples)
  {
	  cout << "Writing " << (int)mVssRays.size() << " samples to file ... ";
	  ExportSamples(mVssRays);
	  cout << "finished\n" << endl;

	  /*VssRayContainer dummyRays;
	  LoadSamples(dummyRays, mObjects);
	  Debug << "rays " << (int)mVssRays.size() << " " << dummyRays.size() << endl;

	  for (int i = 0; i < (int)mVssRays.size(); ++ i)
	  {
		  Debug << mVssRays[i]->GetOrigin() << " " << mVssRays[i]->GetTermination() << " " << mVssRays[i]->mOriginObject << " " << mVssRays[i]->mTerminationObject << endl;
		  Debug << dummyRays[i]->GetOrigin() << " " << dummyRays[i]->GetTermination() << " " << dummyRays[i]->mOriginObject << " " << dummyRays[i]->mTerminationObject << endl << endl;
	  }*/
  }

  
  int numExportRays = 5000;
  //int numExportRays = 0;

  if (numExportRays) {
	char filename[64];
	sprintf(filename, "vss-rays-initial.x3d");
	ExportRays(filename, mVssRays, numExportRays);
  }

  /// compute view cell contribution of rays if view cells manager already constructed
  mViewCellsManager->ComputeSampleContributions(mVssRays);

  // construct view cells
  if (!mDelayedViewCellsConstruction)
	mViewCellsManager->Construct(mObjects, mVssRays);
 
  vssTree = new VssTree;
  // viewcells = Construct(mVssRays);

  vssTree->Construct(mVssRays, mViewSpaceBox);
  cout<<"VssTree root PVS size = "<<vssTree->GetRootPvsSize()<<endl;

  if (0)
  {
	  ExportVssTree("vss-tree-100.x3d", vssTree, Vector3(1,0,0));
	  ExportVssTree("vss-tree-001.x3d", vssTree, Vector3(0,0,1));
	  ExportVssTree("vss-tree-101.x3d", vssTree, Vector3(1,0,1));
	  ExportVssTree("vss-tree-101m.x3d", vssTree, Vector3(-1,0,-1));
	  ExportVssTreeLeaves(vssTree, 10);
  }

  // viewcells->UpdatePVS(newVssRays);
  // get viewcells as kd tree boxes
  vector<AxisAlignedBox3> kdViewcells;
  if (0) {
	vector<KdLeaf *> leaves;
	mKdTree->CollectLeaves(leaves);
	vector<KdLeaf *>::const_iterator it;
	int targetLeaves = 50;
	float prob = targetLeaves/(float)leaves.size();
	for (it = leaves.begin(); it != leaves.end(); ++it)
	  if (RandomValue(0.0f,1.0f) < prob)
		kdViewcells.push_back(mKdTree->GetBox(*it));

	float avgPvs = GetAvgPvsSize(vssTree, kdViewcells);
	cout<<"Initial average PVS size = "<<avgPvs<<endl;
  }


  int samples = 0;
  int pass = 0;

  if (mTestBeamSampling)
	  TestBeamCasting(vssTree, mViewCellsManager);

  // cast view cell samples
  while (1) {
	int num = mVssSamplesPerPass;
	SimpleRayContainer rays;
	VssRayContainer vssRays;

	if (!mUseImportanceSampling) {
	  for (int j=0; j < num; j++) {
	    // changed by matt
		//Vector3 viewpoint = GetViewpoint(mViewSpaceBox);
		Vector3 viewpoint; 
		mViewCellsManager->GetViewPoint(viewpoint);
		Vector3 direction = GetDirection(viewpoint, mViewSpaceBox);
		rays.push_back(SimpleRay(viewpoint, direction));
	  }
	} else {
	  num = GenerateImportanceRays(vssTree, num, rays);
	}

	for (int i=0; i < rays.size(); i++)
	  CastRay(rays[i].mOrigin, rays[i].mDirection, vssRays);

	vssTree->AddRays(vssRays);

	if (0) {
	  int subdivided = vssTree->UpdateSubdivision();
	  cout<<"subdivided leafs = "<<subdivided<<endl;
	}

	float avgPvs = GetAvgPvsSize(vssTree, kdViewcells);
	cout<<"Average PVS size = "<<avgPvs<<endl;

	//Debug << "samples: " << samples << " construction samples " << mViewCellsManager->GetConstructionSamples() << endl;
	// construct view cells after vss
	if (!mViewCellsManager->ViewCellsConstructed() &&
		(samples + mInitialSamples >  mViewCellsManager->GetConstructionSamples()))
	{
		VssRayContainer constructionRays;
		vssTree->CollectRays(constructionRays, 
							 mViewCellsManager->GetConstructionSamples());
		mViewCellsManager->Construct(mObjects, constructionRays);
	}

	/// compute view cell contribution of rays
	mViewCellsManager->ComputeSampleContributions(vssRays);
	
	if (numExportRays) {
	  char filename[64];
	  if (mUseImportanceSampling)
		sprintf(filename, "vss-rays-i%04d.x3d", pass);
	  else
		sprintf(filename, "vss-rays-%04d.x3d", pass);

	  ExportRays(filename, vssRays, numExportRays);
	}

	samples+=num;
	float pvs = vssTree->GetAvgPvsSize();
	cout<<"*****************************\n";
	cout<<samples<<" avgPVS ="<<pvs<<endl;
	cout<<"VssTree root PVS size = "<<vssTree->GetRootPvsSize()<<endl;
	cout<<"*****************************\n";
	if (samples >= mVssSamples)
	  break;
	pass++;
  }


  VssRayContainer viewCellRays;
  
  // compute rays used for view cells construction
  int numRays = Max(mViewCellsManager->GetPostProcessSamples(),
					mViewCellsManager->GetVisualizationSamples());

  vssTree->CollectRays(viewCellRays, numRays);
  
  //-- post process view cells
  mViewCellsManager->PostProcess(mObjects, viewCellRays);

  //-- several visualizations and statistics
  Debug << "\nview cells after post processing: " << endl;
  mViewCellsManager->PrintStatistics(Debug);

  mViewCellsManager->Visualize(mObjects, viewCellRays);
  
  //-- render simulation after merge
  cout << "\nevaluating bsp view cells render time after merge ... ";
  mRenderSimulator->RenderScene();
  SimulationStatistics ss;
  mRenderSimulator->GetStatistics(ss);
  
  cout << " finished" << endl;
  cout << ss << endl;
  Debug << ss << endl;

  delete vssTree;
  
  return true;
}