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#include <CGAL/Timer.h>

/// Nanoflann code
#include <nanoflann.hpp>

#include <cstdlib>
#include <iostream>
#include <fstream>
#include <vector>

using namespace std;
using namespace nanoflann;

template <typename T>
struct Point
{
  Point(T x, T y, T z)
    : x(x), y(y), z(z)
  {}

  T   x,y,z;
};

template <typename T>
ostream& operator <<(ostream& os, const Point<T>& p)
{
  os << p.x << " " << p.y << " " << p.z ;
  return os;
}


// This is an exampleof a custom data set class
template <typename T>
struct PointCloud
{
  std::vector<Point<T> >  pts;

  // Must return the number of data points
  inline size_t kdtree_get_point_count() const { return pts.size(); }

  // Returns the distance between the vector "p1[0:size-1]" and the data point with index "idx_p2" stored in the class:
  inline T kdtree_distance(const T *p1, const size_t idx_p2,size_t /*size*/) const
  {
    const T d0=p1[0]-pts[idx_p2].x;
    const T d1=p1[1]-pts[idx_p2].y;
    const T d2=p1[2]-pts[idx_p2].z;
    return d0*d0+d1*d1+d2*d2;
  }

  // Returns the dim'th component of the idx'th point in the class:
  // Since this is inlined and the "dim" argument is typically an immediate value, the
  //  "if/else's" are actually solved at compile time.
  inline T kdtree_get_pt(const size_t idx, int dim) const
  {
    if (dim==0) return pts[idx].x;
    else if (dim==1) return pts[idx].y;
    else return pts[idx].z;
  }

  // Optional bounding-box computation: return false to default to a standard bbox computation loop.
  //   Return true if the BBOX was already computed by the class and returned in "bb" so it can be avoided to redo it again.
  //   Look at bb.size() to find out the expected dimensionality (e.g. 2 or 3 for point clouds)
  template <class BBOX>
  bool kdtree_get_bbox(BBOX &) const { return false; }

};

template <typename T>
void generateRandomPointCloud(PointCloud<T> &point, istream& is)
{
  T x, y, z;
  while(is >> x >> y  >> z){
    point.pts.push_back(Point<T>(x,y,z));
  }
  std::cout << "Read "<< point.pts.size() << " points\n";
}

template <typename num_t>
void run_nanoflann()
{
  PointCloud<num_t> cloud;


  // Generate points:
        std::ifstream input("points.xyz");
  generateRandomPointCloud(cloud, input);

        std::vector<Point<double> > queries;
        std::ifstream queries_stream("queries.xyz");
        
        double x,y,z;
        while( queries_stream >> x >> y >> z){
          queries.push_back(Point<double>(x,y,z));
        }

  num_t query_pt[3] = { 0, 0, 0};

        CGAL::Timer timer;
        timer.start();
  // construct a kd-tree index:
  typedef KDTreeSingleIndexAdaptor<
    L2_Simple_Adaptor<num_t, PointCloud<num_t> > ,
    PointCloud<num_t>,
    3 /* dim */
    > my_kd_tree_t;

  my_kd_tree_t   index(3 /*dim*/, cloud, KDTreeSingleIndexAdaptorParams(10 /* max leaf */) );
  index.buildIndex();

        timer.stop();
        std::cout << "construction time: " << timer.time() << " sec" << std::endl;
        
        timer.reset();
        timer.start();
  // do a knn search
  const size_t num_results = 50;
  size_t ret_index[50];
  num_t out_dist_sqr[50];
        int size = cloud.pts.size();
        
        std::cout << "start search" << std::endl;
        double sum = 0;
        for(int i = 0 ; i < size; i++){
          query_pt[0] = queries[i].x;
          query_pt[1] = queries[i].y;
          query_pt[2] = queries[i].z;
          nanoflann::KNNResultSet<num_t> resultSet(num_results);
          resultSet.init(ret_index, out_dist_sqr );
          index.findNeighbors(resultSet, &query_pt[0], nanoflann::SearchParams(10,0));

          //std::cout << "knnSearch(nn="<<num_results<<"): \n";
          //std::cout << "ret_index=" << ret_index << " out_dist_sqr=" << out_dist_sqr << endl;
          //std::cout << cloud.pts[ret_index] << std::endl;
          for (std::size_t k=0; k<num_results; ++k)
            sum += cloud.pts[ret_index[k]].x;
        }
        timer.stop();
        std::cout << sum << " done in " << timer.time() << " sec."<< std::endl;
}
/// End of Nanoflann code

/// CGAL code
#include <CGAL/Simple_cartesian.h>
#include <CGAL/Orthogonal_k_neighbor_search.h>
#include <CGAL/Search_traits_3.h>
#include <vector>
#include <cmath>
#include <iostream>
#include <fstream>

typedef CGAL::Simple_cartesian<double> K;
typedef K::Point_3 Point_d;
typedef CGAL::Search_traits_3<K> TreeTraits;
typedef CGAL::Orthogonal_k_neighbor_search<TreeTraits> Neighbor_search;
typedef Neighbor_search::Tree Tree;


void run_cgal() {
  CGAL::Timer timer;
  timer.start();

  std::vector<Point_d> points, queries;
  Point_d p;

  std::ifstream point_stream("points.xyz");
  while(point_stream >> p){
    points.push_back(p);

  }


  std::ifstream query_stream("queries.xyz");
  while(query_stream >> p ){
    queries.push_back(p);

  }
  timer.stop();
  std::cerr << "reading points took " << timer.time() << " sec." << std::endl;


  timer.reset();
  timer.start();
  Tree tree(points.begin(), points.end());
  tree.build();
  timer.stop();
  std::cerr << "tree construction took " << timer.time() << " sec." << std::endl;


  // Initialize the search structure, and search all N points
  
  double d = 0;
  timer.reset();
  timer.start();
  for(std::size_t i = 0; i < queries.size(); i++){
    Neighbor_search search(tree, queries[i], 50, 0);

    // report the N nearest neighbors and their distance
    // This should sort all N points by increasing distance from origin
    for(Neighbor_search::iterator it = search.begin(); it != search.end(); ++it){
      //std::cout << it->first << std::endl;
      d += it->first.x();
    }
  }
  timer.stop();
  std::cerr << d << std::endl;
  std::cerr << queries.size() << " queries in " << timer.time() << " sec." << std::endl;
}
/// End of CGAL code


int main()
{
  std::cout << "CGAL\n";
  run_cgal();
  std::cout << "Nanoflann\n";
  run_nanoflann<double>();
}