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 * Copyright 2011-2022 Jose Luis Blanco (joseluisblancoc@gmail.com).
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#include <nanoflann.hpp>
using namespace nanoflann;

#include "KDTreeVectorOfVectorsAdaptor.h"

#include <ctime>
#include <cstdlib>
#include <iostream>

const int SAMPLES_DIM = 15;

typedef std::vector<std::vector<double> > my_vector_of_vectors_t;


void generateRandomPointCloud(my_vector_of_vectors_t &samples, const size_t N, const size_t dim, const double max_range = 10.0)
{
	std::cout << "Generating "<< N << " random points...";
	samples.resize(N);
	for (size_t i = 0; i < N; i++)
	{
		samples[i].resize(dim);
		for (size_t d = 0; d < dim; d++)
			samples[i][d] = max_range * (rand() % 1000) / (1000.0);
	}
	std::cout << "done\n";
}

void kdtree_demo(const size_t nSamples, const size_t dim)
{
	my_vector_of_vectors_t  samples;

	const double max_range = 20;

	// Generate points:
	generateRandomPointCloud(samples, nSamples,dim, max_range);

	// Query point:
	std::vector<double> query_pt(dim);
	for (size_t d = 0;d < dim; d++)
		query_pt[d] = max_range * (rand() % 1000) / (1000.0);

	// construct a kd-tree index:
	// Dimensionality set at run-time (default: L2)
	// ------------------------------------------------------------
	typedef KDTreeVectorOfVectorsAdaptor< my_vector_of_vectors_t, double >  my_kd_tree_t;

	my_kd_tree_t   mat_index(dim /*dim*/, samples, 10 /* max leaf */ );
	mat_index.index->buildIndex();

	// do a knn search
	const size_t num_results = 3;
	std::vector<size_t>   ret_indexes(num_results);
	std::vector<double> out_dists_sqr(num_results);

	nanoflann::KNNResultSet<double> resultSet(num_results);

	resultSet.init(&ret_indexes[0], &out_dists_sqr[0] );
	mat_index.index->findNeighbors(resultSet, &query_pt[0], nanoflann::SearchParams(10));

	std::cout << "knnSearch(nn="<<num_results<<"): \n";
	for (size_t i = 0; i < num_results; i++)
		std::cout << "ret_index["<<i<<"]=" << ret_indexes[i] << " out_dist_sqr=" << out_dists_sqr[i] << std::endl;
}

int main()
{
	// Randomize Seed
	srand(static_cast<unsigned int>(time(nullptr)));
	kdtree_demo(1000 /* samples */, SAMPLES_DIM /* dim */);
}
