#include "IntersectableWrapper.h"
#include "Mesh.h"
#include "Triangle3.h"
#include "KdTree.h"
#include "BvHierarchy.h"
#include "SimpleRay.h"


namespace GtpVisibilityPreprocessor {


AxisAlignedBox3 TriangleIntersectable::GetBox() const
{	
  return mItem.GetBoundingBox();
}


int
TriangleIntersectable::CastSimpleRay(const SimpleRay &ray)
{
  static Vector3 nearestNormal;
  // std::cout << "To be done - ray triangle intersection\n" << std::endl;
  const int hitCode = mItem.CastSimpleRay(ray,
					  SimpleRay::IntersectionRes[0].tdist,
					  SimpleRay::IntersectionRes[0].maxt);
  if (hitCode == Ray::INTERSECTION) {
    SimpleRay::IntersectionRes[0].intersectable = this;
    SimpleRay::IntersectionRes[0].maxt = SimpleRay::IntersectionRes[0].tdist;
    return 1; // intersection occured
  }
  return 0; // no intersection
}

int
TriangleIntersectable::CastSimpleRay(const SimpleRay &ray, int rayIndex)
{
  const int hitCode =
    mItem.CastSimpleRay(ray,
			SimpleRay::IntersectionRes[rayIndex].tdist,
			SimpleRay::IntersectionRes[rayIndex].maxt);
  if (hitCode == Ray::INTERSECTION) {
    SimpleRay::IntersectionRes[rayIndex].intersectable = this;
    // we copy the closest distance so far - it prunes the search
    // when more triangles in the same leaf and assures the
    // correctness.
    SimpleRay::IntersectionRes[rayIndex].maxt =
      SimpleRay::IntersectionRes[rayIndex].tdist;
    return 1; // intersection occured
  }
  return 0; // no intersection
}

  
int TriangleIntersectable::CastRay(Ray &ray)
{	
  float nearestT = MAX_FLOAT;
  float t;
  Vector3 nearestNormal;
  
  if (ray.GetType() == Ray::LOCAL_RAY && !ray.intersections.empty())
    nearestT = ray.intersections[0].mT;
  
  const int hitCode = mItem.CastRay(ray, t, nearestT, nearestNormal);
  
  nearestT = t;
  
  if (hitCode == Ray::INTERSECTION) {
    if (ray.GetType() == Ray::LOCAL_RAY && !ray.intersections.empty()) {
      ray.intersections[0] = Ray::Intersection(nearestT,
					       nearestNormal,
					       this,
					       0);
    }
    else {
      ray.intersections.push_back(Ray::Intersection(nearestT,
						    nearestNormal,
						    this,
						    0));
    }
    
    return 1;
  }
  
  return 0;
}
	

int TriangleIntersectable::NumberOfFaces() const
{
	return 1;
}


Vector3
TriangleIntersectable::GetNormal(const int idx) const
{
  return mItem.GetNormal();
}


int
TriangleIntersectable::GetRandomSurfacePoint(Vector3 &point, Vector3 &normal)
{
	// random barycentric coordinates
	float a = RandomValue(0.0f, 1.0f);
	float b = RandomValue(0.0f, 1.0f);
	float c = RandomValue(0.0f, 1.0f);
	
	const float sum = a + b + c;

	// scale so we get vaccumated value of 1
	if (sum)
	{
		a /= sum;
		b /= sum;
		c /= sum;
	}

	//cout << "a: " << a << " b: " << b << " c: " << c << " sum: " << sum << endl;
	point = mItem.mVertices[0] * a + mItem.mVertices[1] * b + mItem.mVertices[2] * c;
	normal = mItem.GetNormal();

	return 0;
}


int
TriangleIntersectable::GetRandomSurfacePoint(const float u,
											 const float v,
											 Vector3 &point,
											 Vector3 &normal)
{
  // random barycentric coordinates
  float a = u;
  float b = v;
  float c = 1.0f - u - v;
  
  point = mItem.mVertices[0] * a + mItem.mVertices[1] * b + mItem.mVertices[2] * c;
  normal = mItem.GetNormal();
  
  return 0;
}



int TriangleIntersectable::GetRandomVisibleSurfacePoint(Vector3 &point,
														Vector3 &normal,
														const Vector3 &viewpoint,
														const int maxTries)
{
	return GetRandomSurfacePoint(point, normal);
}


int TriangleIntersectable::GetRandomEdgePoint(Vector3 &point, Vector3 &normal)
{
	const int edge = Random(3);

	const Vector3 a = mItem.mVertices[edge];
	const Vector3 b = mItem.mVertices[(edge + 1) % 3];

	const float factor = RandomValue(0.0f, 1.0f);

	point = a * factor + b * factor;
	normal = mItem.GetNormal();

	return edge;
}


KdIntersectable::KdIntersectable(KdNode *item, const AxisAlignedBox3 &box) :
  IntersectableWrapper<KdNode *>(item), mNumTriangles(-1), mBox(box), mGenericIdx(-1)
{
}


int KdIntersectable::ComputeNumTriangles()
{
	Intersectable::NewMail();

	std::stack<KdNode *> tStack;
	tStack.push(mItem);

	if (mNumTriangles != -1)
		return mNumTriangles;

	mNumTriangles = 0;

	while (!tStack.empty())
	{
		KdNode *node = tStack.top();
		tStack.pop();

		if (!node->IsLeaf()) 
		{
			KdInterior *kdInterior = static_cast<KdInterior *>(node);

			tStack.push(kdInterior->mBack);
			tStack.push(kdInterior->mFront);
		} 
		else 
		{
			KdLeaf *leaf = static_cast<KdLeaf *>(node);

			int tri = 0;

			for (size_t i = 0; i < leaf->mObjects.size(); ++ i)
			{
				TriangleIntersectable *obj = 
					static_cast<TriangleIntersectable *>(leaf->mObjects[i]);
				
				// check if already accounted for
				if (!obj->Mailed())
				{
					obj->Mail();
					++ tri;
				}
			}

            mNumTriangles += tri;
		}
	}

	return mNumTriangles;
}


SceneGraphLeafIntersectable::SceneGraphLeafIntersectable(SceneGraphLeaf *item, const AxisAlignedBox3 &box):
  IntersectableWrapper<SceneGraphLeaf *>(item), mBox(box)
{
}

}