// Gmsh - Copyright (C) 1997-2015 C. Geuzaine, J.-F. Remacle
//
// See the LICENSE.txt file for license information. Please report all
// bugs and problems to the public mailing list <gmsh@geuz.org>.

#include "closestPoint.h"
#include "GEntity.h"
#include "GEdge.h"
#include "GFace.h"
#include <vector>

static void oversample (std::vector<SPoint3> &s, double tol){
  std::vector<SPoint3> t;
  for (unsigned int i=1;i<s.size();i++){
    SPoint3 p0 = s[i-1];
    SPoint3 p1 = s[i];
    double d = p0.distance(p1);
    int N = (int) (d / tol);
    t.push_back(p0);
    for (int j=1;j<N;j++){
      const double xi = (double) j/ N;
      t.push_back(p0 + (p1-p0)*xi);
    }
    t.push_back(p1);
  }
  s = t;
}

closestPointFinder :: closestPointFinder (GEntity *ge, double e) : _tolerance (e)
{
#if defined(HAVE_ANN)
  std::vector<SPoint3> pts;
  if (ge->dim() == 1){
    GEdge *edge = ge->cast2Edge();
    if (edge){
      std::vector<double> ts;
      edge->discretize(_tolerance, pts,ts);
      //    printf("%d points\n",pts.size());
      oversample (pts, _tolerance);
      //    printf("%d points after oversampling\n",pts.size());
    }
    else{
      Msg::Error("Can get edge in closestPointFinder");
    }
  }
  index = new ANNidx[1];
  dist = new ANNdist[1];
  zeronodes = annAllocPts(pts.size(), 3);
  for (unsigned int k=0;k<pts.size();k++){
    zeronodes[k][0] = pts[k].x();
    zeronodes[k][1] = pts[k].y();
    zeronodes[k][2] = pts[k].z();
  }
  kdtree = new ANNkd_tree(zeronodes, pts.size(), 3);
#else
  Msg::Fatal("Gmsh should be compiled using ANN");
#endif
}

closestPointFinder :: ~closestPointFinder ()
{
#if defined(HAVE_ANN)
  if(kdtree) delete kdtree;
  if(zeronodes) annDeallocPts(zeronodes);
  delete[]index;
  delete[]dist;
#endif
}

SPoint3 closestPointFinder ::operator() (const SPoint3 &p)
{
#if defined(HAVE_ANN)
  double xyz[3] = {p.x(),p.y(),p.z()};
  kdtree->annkSearch(xyz, 1, index, dist);
  return SPoint3(zeronodes[index[0]][0],
		 zeronodes[index[0]][1],
		 zeronodes[index[0]][2]);
#else
  return p;
#endif
}

