#include <iostream>
#include "opencv2/core.hpp"
#ifdef HAVE_OPENCV_XFEATURES2D
#include "opencv2/highgui.hpp"
#include "opencv2/features2d.hpp"
#include "opencv2/xfeatures2d.hpp"

using namespace cv;
using namespace cv::xfeatures2d;
using std::cout;
using std::endl;

const char* keys =
    "{ help h |                  | Print help message. }"
    "{ input1 | box.png          | Path to input image 1. }"
    "{ input2 | box_in_scene.png | Path to input image 2. }";

int main( int argc, char* argv[] )
{
    CommandLineParser parser( argc, argv, keys );
    Mat img1 = imread( samples::findFile( parser.get<String>("input1") ), IMREAD_GRAYSCALE );
    Mat img2 = imread( samples::findFile( parser.get<String>("input2") ), IMREAD_GRAYSCALE );
    if ( img1.empty() || img2.empty() )
    {
        cout << "Could not open or find the image!\n" << endl;
        parser.printMessage();
        return -1;
    }

    //-- Step 1: Detect the keypoints using SURF Detector, compute the descriptors
    int minHessian = 400;
    Ptr<SURF> detector = SURF::create( minHessian );
    std::vector<KeyPoint> keypoints1, keypoints2;
    Mat descriptors1, descriptors2;
    detector->detectAndCompute( img1, noArray(), keypoints1, descriptors1 );
    detector->detectAndCompute( img2, noArray(), keypoints2, descriptors2 );

    //-- Step 2: Matching descriptor vectors with a brute force matcher
    // Since SURF is a floating-point descriptor NORM_L2 is used
    Ptr<DescriptorMatcher> matcher = DescriptorMatcher::create(DescriptorMatcher::BRUTEFORCE);
    std::vector< DMatch > matches;
    matcher->match( descriptors1, descriptors2, matches );

    //-- Draw matches
    Mat img_matches;
    drawMatches( img1, keypoints1, img2, keypoints2, matches, img_matches );

    //-- Show detected matches
    imshow("Matches", img_matches );

    waitKey();
    return 0;
}
#else
int main()
{
    std::cout << "This tutorial code needs the xfeatures2d contrib module to be run." << std::endl;
    return 0;
}
#endif