#include "EmbreeRenderer.h"
// Implementation

//IGL viewing parts
#include "../unproject.h"
#include "../look_at.h"
#include "../frustum.h"
#include "../ortho.h"

// color map
#include "../jet.h"

#include "../PI.h"


IGL_INLINE void igl::embree::EmbreeRenderer::init_view()
{
  camera_base_zoom = 1.0f;
  camera_zoom = 1.0f;

  camera_view_angle = 45.0;
  camera_dnear = 1.0;
  camera_dfar = 100.0;
  camera_base_translation << 0, 0, 0;
  camera_translation << 0, 0, 0;
  camera_eye << 0, 0, 5;
  camera_center << 0, 0, 0;
  camera_up << 0, 1, 0;
  
  rot_matrix = Eigen::Matrix3f::Identity();

  view = Eigen::Matrix4f::Identity();
  proj = Eigen::Matrix4f::Identity();
  norm = Eigen::Matrix4f::Identity();

  orthographic = false;
  

}

IGL_INLINE igl::embree::EmbreeRenderer::EmbreeRenderer()
  :
  scene(NULL),
  geomID(0),
  initialized(false),
  device(igl::embree::EmbreeDevice::get_device())
{
  init_view();
  uC << 1,0,0;
  double_sided = false;
}

IGL_INLINE igl::embree::EmbreeRenderer::EmbreeRenderer(
  const EmbreeRenderer &)
  :// To make -Weffc++ happy
  scene(NULL),
  geomID(0),
  initialized(false)
{
  assert(false && "Embree: Copying EmbreeRenderer is not allowed");
}

IGL_INLINE igl::embree::EmbreeRenderer & igl::embree::EmbreeRenderer::operator=(
  const EmbreeRenderer &)
{
  assert(false && "Embree: Assigning an EmbreeRenderer is not allowed");
  return *this;
}


IGL_INLINE void igl::embree::EmbreeRenderer::init(
  const PointMatrixType& V,
  const FaceMatrixType& F,
  bool isStatic)
{
  std::vector<const PointMatrixType*> Vtemp;
  std::vector<const FaceMatrixType*> Ftemp;
  std::vector<int> masks;
  Vtemp.push_back(&V);
  Ftemp.push_back(&F);
  masks.push_back(0xFFFFFFFF);
  init(Vtemp,Ftemp,masks,isStatic);
}

IGL_INLINE void igl::embree::EmbreeRenderer::init(
  const std::vector<const PointMatrixType*>& V,
  const std::vector<const FaceMatrixType*>&  F,
  const std::vector<int>& masks,
  bool isStatic)
{
  if(initialized)
    deinit();

  using namespace std;

  if(V.size() == 0 || F.size() == 0)
  {
    std::cerr << "Embree: No geometry specified!";
    return;
  }
  RTCBuildQuality buildQuality = isStatic ? RTC_BUILD_QUALITY_HIGH : RTC_BUILD_QUALITY_MEDIUM;

  // create a scene
  scene = rtcNewScene(device);
  rtcSetSceneFlags(scene, RTC_SCENE_FLAG_ROBUST);
  rtcSetSceneBuildQuality(scene, buildQuality);

  for(int g=0;g<(int)V.size();g++)
  {
    // create triangle mesh geometry in that scene
    RTCGeometry geom_0 = rtcNewGeometry (device, RTC_GEOMETRY_TYPE_TRIANGLE);
    rtcSetGeometryBuildQuality(geom_0, buildQuality);
    rtcSetGeometryTimeStepCount(geom_0,1);
    geomID = rtcAttachGeometry(scene,geom_0);
    rtcReleaseGeometry(geom_0);

    // fill vertex buffer, have to be 16 byte wide( sizeof(float)*4 )
    Eigen::Map<Eigen::Matrix<float,-1,4,Eigen::RowMajor>> vertices(
        (float*)rtcSetNewGeometryBuffer(geom_0,RTC_BUFFER_TYPE_VERTEX,0,RTC_FORMAT_FLOAT3,4*sizeof(float),V[g]->rows()),
        V[g]->rows(),4
    );
    vertices.block(0,0,V[g]->rows(),3) = V[g]->cast<float>();

    // fill triangle buffer
    Eigen::Map<Eigen::Matrix<unsigned int,-1,3,Eigen::RowMajor>> triangles(
      (unsigned int*) rtcSetNewGeometryBuffer(geom_0,RTC_BUFFER_TYPE_INDEX,0,RTC_FORMAT_UINT3,3*sizeof(unsigned int), F[g]->rows()),
      F[g]->rows(),3
    );
    triangles = F[g]->cast<unsigned int>();
    //TODO: store vertices and triangles in array for whatever reason?

    rtcSetGeometryMask(geom_0, masks[g]);
    rtcCommitGeometry(geom_0);
  }

  rtcCommitScene(scene);

  if(rtcGetDeviceError (device) != RTC_ERROR_NONE)
      std::cerr << "Embree: An error occurred while initializing the provided geometry!" << endl;
#ifdef IGL_VERBOSE
  else
    std::cerr << "Embree: geometry added." << endl;
#endif

  initialized = true;
}

IGL_INLINE igl::embree::EmbreeRenderer::~EmbreeRenderer()
{
  if(initialized)
    deinit();
  
  igl::embree::EmbreeDevice::release_device();
}

IGL_INLINE void igl::embree::EmbreeRenderer::deinit()
{
  if(scene)
  {
    rtcReleaseScene(scene);

    if(rtcGetDeviceError (device) != RTC_ERROR_NONE)
    {
        std::cerr << "Embree: An error occurred while resetting!" << std::endl;
    }
#ifdef IGL_VERBOSE
    else
    {
      std::cerr << "Embree: geometry removed." << std::endl;
    }
#endif
  }
}

IGL_INLINE bool igl::embree::EmbreeRenderer::intersect_ray(
  const Eigen::RowVector3f& origin,
  const Eigen::RowVector3f& direction,
  Hit&  hit,
  float tnear,
  float tfar,
  int mask) const
{
  RTCRayHit ray;
  ray.ray.flags = 0;
  create_ray(ray, origin,direction,tnear,tfar,mask);

  // shot ray
  {
    RTCIntersectContext context;
    rtcInitIntersectContext(&context);
    rtcIntersect1(scene, &context, &ray);
    ray.hit.Ng_x = -ray.hit.Ng_x; // EMBREE_FIXME: only correct for triangles,quads, and subdivision surfaces
    ray.hit.Ng_y = -ray.hit.Ng_y;
    ray.hit.Ng_z = -ray.hit.Ng_z;
  }
#ifdef IGL_VERBOSE
  if(rtcGetDeviceError (device) != RTC_ERROR_NONE)
      std::cerr << "Embree: An error occurred while resetting!" << std::endl;
#endif

  if((unsigned)ray.hit.geomID != RTC_INVALID_GEOMETRY_ID)
  {
    hit.id = ray.hit.primID;
    hit.gid = ray.hit.geomID;
    hit.u = ray.hit.u;
    hit.v = ray.hit.v;
    hit.t = ray.ray.tfar;
    hit.N = Vec3f(ray.hit.Ng_x, ray.hit.Ng_y, ray.hit.Ng_z);
    return true;
  }

  return false;
}

IGL_INLINE void 
igl::embree::EmbreeRenderer
::create_ray(RTCRayHit& ray, const Eigen::RowVector3f& origin, 
 const Eigen::RowVector3f& direction, float tnear, float tfar, int mask) const
{
  ray.ray.org_x = origin[0];
  ray.ray.org_y = origin[1];
  ray.ray.org_z = origin[2];
  ray.ray.dir_x = direction[0];
  ray.ray.dir_y = direction[1];
  ray.ray.dir_z = direction[2];
  ray.ray.tnear = tnear;
  ray.ray.tfar = tfar;
  ray.ray.id = RTC_INVALID_GEOMETRY_ID;
  ray.ray.mask = mask;
  ray.ray.time = 0.0f;

  ray.hit.geomID = RTC_INVALID_GEOMETRY_ID;
  ray.hit.instID[0] = RTC_INVALID_GEOMETRY_ID;
  ray.hit.primID = RTC_INVALID_GEOMETRY_ID;
}


template <typename DerivedV, typename DerivedF>
IGL_INLINE void
igl::embree::EmbreeRenderer
::set_mesh(const Eigen::MatrixBase<DerivedV> & MV,
           const Eigen::MatrixBase<DerivedF> & MF,
           bool is_static)
{
  V = MV.template cast<float>();
  F = MF;
  this->init(V,F,is_static);

  auto min_point = V.colwise().minCoeff();
  auto max_point = V.colwise().maxCoeff();
  auto centroid  = (0.5*(min_point + max_point)).eval();

  camera_base_translation.setConstant(0);
  camera_base_translation.head(centroid.size()) = -centroid.cast<float>();
  camera_base_zoom = 2.0 / (max_point-min_point).array().abs().maxCoeff();
}

IGL_INLINE void
igl::embree::EmbreeRenderer
::render_buffer(PixelMatrixType& R, PixelMatrixType&G, PixelMatrixType &B,PixelMatrixType &A)
{
  assert(R.rows()==G.rows());assert(R.rows()==B.rows());assert(R.rows()==A.rows());
  assert(R.cols()==G.cols());assert(R.cols()==B.cols());assert(R.cols()==A.cols());

  Eigen::Vector4f viewport(0,0,R.rows(),R.cols());

  float width  = R.rows();
  float height = R.cols();

  // update view matrix
  igl::look_at( camera_eye, camera_center, camera_up, view);

  view = view
    * (rot_matrix * Eigen::Scaling(camera_zoom * camera_base_zoom)
    * Eigen::Translation3f(camera_translation + camera_base_translation)).matrix();
  
  if (orthographic)
  {
    float length = (camera_eye - camera_center).norm();
    float h = tan(camera_view_angle/360.0 * igl::PI) * (length);
    igl::ortho(-h*width/height, h*width/height, -h, h, camera_dnear, camera_dfar, proj);
  } else {
    float fH = tan(camera_view_angle / 360.0 * igl::PI) * camera_dnear;
    float fW = fH * (double)width/(double)height;
    igl::frustum(-fW, fW, -fH, fH, camera_dnear, camera_dfar, proj);
  }

  // go over all pixels in the "view"
  for(int x=0;x<(int)width;++x) 
  {
    for(int y=0;y<(int)height;++y) 
    {
      Vec3f s,d,dir;
      igl::embree::EmbreeRenderer::Hit hit;

      // look into the screen
      Vec3f win_s(x,y,0);
      Vec3f win_d(x,y,1);
      // Source, destination and direction in world
      igl::unproject(win_s,this->view,this->proj,viewport,s);
      igl::unproject(win_d,this->view,this->proj,viewport,d);
      dir = d-s;
      dir.normalize();

      auto clamp=[](float x)->unsigned char {return (unsigned char)(x<0?0:x>1.0?255:x*255);};

      if(this->intersect_ray(s,dir,hit))
      {
        if ( double_sided || dir.dot(hit.N) > 0.0f )
        {
          // TODO: interpolate normals ?
          hit.N.normalize();

          // cos between ray and face normal
          // negative projection will indicate back side
          float face_proj = fabs(dir.dot(hit.N));

          Eigen::RowVector3f c;

          if(this->uniform_color)
          {
            // same color for the whole mesh
            c=this->uC;
          } else if(this->face_based) {
            // flat color per face
            c=this->C.row(hit.id);
          } else { //use barycentric coordinates to interpolate colour
              c=this->C.row(F(hit.id,1))*hit.u+
                this->C.row(F(hit.id,2))*hit.v+
                this->C.row(F(hit.id,0))*(1.0-hit.u-hit.v);
          }

          R(x,y) = clamp(face_proj*c(0));
          G(x,y) = clamp(face_proj*c(1));
          B(x,y) = clamp(face_proj*c(2));
        } else {
          // backface?
          R(x,y)=0;
          G(x,y)=0;
          B(x,y)=0;
        }
        // give the same alpha to all points with something behind
        A(x,y)=255; 
      } else {
        R(x,y)=0;
        G(x,y)=0;
        B(x,y)=0;
        A(x,y)=0;
      }

    }
  }
}


template <typename DerivedC>
IGL_INLINE void
igl::embree::EmbreeRenderer
::set_colors(const Eigen::MatrixBase<DerivedC> & C)
{
  if(C.rows()==V.rows()) // per vertex color
  {
    face_based = false;
    this->C = C.template cast<float>();
    this->uniform_color=false;
  } else if (C.rows()==F.rows()) {
    face_based = true;
    this->C = C.template cast<float>();
    this->uniform_color=false;
  } else if (C.rows()==1) {
    face_based = true;
    this->uC = C.template cast<float>();
    this->uniform_color=true;
  }else {
    // don't know what to do
    this->uniform_color=true;
    assert(false); //?
  }
}

template <typename DerivedD>
IGL_INLINE void
igl::embree::EmbreeRenderer
::set_data(const Eigen::MatrixBase<DerivedD> & D, igl::ColorMapType cmap)
{
  const auto caxis_min = D.minCoeff();
  const auto caxis_max = D.maxCoeff();
  return set_data(D,caxis_min,caxis_max,cmap);
}


template <typename DerivedD, typename T>
IGL_INLINE void igl::embree::EmbreeRenderer::set_data(
  const Eigen::MatrixBase<DerivedD> & D,
  T caxis_min,
  T caxis_max,
  igl::ColorMapType cmap)
{
    Eigen::Matrix<T, -1, -1> C;
    igl::colormap(cmap,D,caxis_min,caxis_max,C);
    set_colors(C);
}

template <typename Derivedr>
IGL_INLINE void 
igl::embree::EmbreeRenderer::set_rot(const Eigen::MatrixBase<Derivedr> &r)
{
  this->rot_matrix = r.template cast<float>();
}

template <typename T>
IGL_INLINE void 
igl::embree::EmbreeRenderer::set_zoom(T zoom)
{
  this->camera_zoom=zoom;
}

template <typename Derivedtr>
IGL_INLINE void 
igl::embree::EmbreeRenderer::set_translation(const Eigen::MatrixBase<Derivedtr> &tr)
{
  this->camera_translation=tr.template cast<float>();
}

IGL_INLINE void 
igl::embree::EmbreeRenderer::set_face_based(bool _f)
{
  this->face_based=_f;
}

IGL_INLINE void 
igl::embree::EmbreeRenderer::set_orthographic(bool o)
{
  this->orthographic=o;
}

IGL_INLINE void 
igl::embree::EmbreeRenderer::set_double_sided(bool d)
{
  this->double_sided=d;
}


#ifdef IGL_STATIC_LIBRARY
template void igl::embree::EmbreeRenderer::set_rot<Eigen::Matrix<double, 3, 3, 0, 3, 3> >(Eigen::MatrixBase<Eigen::Matrix<double, 3, 3, 0, 3, 3> > const&);
template void igl::embree::EmbreeRenderer::set_data<Eigen::Matrix<double, -1, 1, 0, -1, 1> >(Eigen::MatrixBase<Eigen::Matrix<double, -1, 1, 0, -1, 1> > const&, igl::ColorMapType);
template void igl::embree::EmbreeRenderer::set_mesh<Eigen::Matrix<double, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, -1, 0, -1, -1> >(Eigen::MatrixBase<Eigen::Matrix<double, -1, -1, 0, -1, -1> > const&, Eigen::MatrixBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> > const&, bool);
template void igl::embree::EmbreeRenderer::set_zoom<double>(double);
#endif //IGL_STATIC_LIBRARY
