// ----------------------------------------------------------------------------
// -                        Open3D: www.open3d.org                            -
// ----------------------------------------------------------------------------
// The MIT License (MIT)
//
// Copyright (c) 2018 www.open3d.org
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
// ----------------------------------------------------------------------------

#include <Eigen/Dense>
#include <cstdio>
#include <vector>

#include "Open3D/Open3D.h"

int main(int argc, char **argv) {
    using namespace open3d;
    using namespace flann;

    utility::SetVerbosityLevel(utility::VerbosityLevel::Debug);

    if (argc < 2) {
        PrintOpen3DVersion();
        // clang-format off
        utility::LogInfo("Usage:");
        utility::LogInfo("    > LineSet [filename]");
        utility::LogInfo("    The program will :");
        utility::LogInfo("    1. load the pointcloud in [filename].");
        utility::LogInfo("    2. use KDTreeFlann to compute 50 nearest neighbors of point0.");
        utility::LogInfo("    3. convert the correspondences to LineSet and render it.");
        utility::LogInfo("    4. rotate the point cloud slightly to get another point cloud.");
        utility::LogInfo("    5. find closest point of the original point cloud on the new point cloud, mark as correspondences.");
        utility::LogInfo("    6. convert to LineSet and render it.");
        utility::LogInfo("    7. distance below 0.05 are rendered as red, others as black.");
        // clang-format on
        return 1;
    }

    auto cloud_ptr = io::CreatePointCloudFromFile(argv[1]);
    std::vector<std::pair<int, int>> correspondences;

    const int nn = 50;
    geometry::KDTreeFlann kdtree;
    kdtree.SetGeometry(*cloud_ptr);
    std::vector<int> indices_vec(nn);
    std::vector<double> dists_vec(nn);
    kdtree.SearchKNN(cloud_ptr->points_[0], nn, indices_vec, dists_vec);
    for (int i = 0; i < nn; i++) {
        correspondences.push_back(std::make_pair(0, indices_vec[i]));
    }
    auto lineset_ptr = geometry::LineSet::CreateFromPointCloudCorrespondences(
            *cloud_ptr, *cloud_ptr, correspondences);
    visualization::DrawGeometries({cloud_ptr, lineset_ptr});

    auto new_cloud_ptr = std::make_shared<geometry::PointCloud>();
    *new_cloud_ptr = *cloud_ptr;
    auto bounding_box = new_cloud_ptr->GetAxisAlignedBoundingBox();
    Eigen::Matrix4d trans_to_origin = Eigen::Matrix4d::Identity();
    trans_to_origin.block<3, 1>(0, 3) = bounding_box.GetCenter() * -1.0;
    Eigen::Matrix4d transformation = Eigen::Matrix4d::Identity();
    transformation.block<3, 3>(0, 0) = static_cast<Eigen::Matrix3d>(
            Eigen::AngleAxisd(M_PI / 6.0, Eigen::Vector3d::UnitX()));
    new_cloud_ptr->Transform(trans_to_origin.inverse() * transformation *
                             trans_to_origin);
    correspondences.clear();
    for (size_t i = 0; i < new_cloud_ptr->points_.size(); i++) {
        kdtree.SearchKNN(new_cloud_ptr->points_[i], 1, indices_vec, dists_vec);
        correspondences.push_back(std::make_pair(indices_vec[0], (int)i));
    }
    auto new_lineset_ptr =
            geometry::LineSet::CreateFromPointCloudCorrespondences(
                    *cloud_ptr, *new_cloud_ptr, correspondences);
    new_lineset_ptr->colors_.resize(new_lineset_ptr->lines_.size());
    for (size_t i = 0; i < new_lineset_ptr->lines_.size(); i++) {
        auto point_pair = new_lineset_ptr->GetLineCoordinate(i);
        if ((point_pair.first - point_pair.second).norm() <
            0.05 * bounding_box.GetMaxExtent()) {
            new_lineset_ptr->colors_[i] = Eigen::Vector3d(1.0, 0.0, 0.0);
        } else {
            new_lineset_ptr->colors_[i] = Eigen::Vector3d(0.0, 0.0, 0.0);
        }
    }
    visualization::DrawGeometries({cloud_ptr, new_cloud_ptr, new_lineset_ptr});

    return 0;
}