// Copyright (c) 2023, ETH Zurich and UNC Chapel Hill.
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#include "colmap/estimators/similarity_transform.h"

#include "colmap/geometry/sim3.h"
#include "colmap/math/random.h"
#include "colmap/util/eigen_alignment.h"

#include <Eigen/Core>
#include <gtest/gtest.h>

namespace colmap {
namespace {

void TestEstimateSim3dWithNumCoords(const size_t num_coords) {
  const Sim3d gt_tgt_from_src(RandomUniformReal<double>(0.1, 10),
                              Eigen::Quaterniond::UnitRandom(),
                              Eigen::Vector3d::Random());

  std::vector<Eigen::Vector3d> src;
  std::vector<Eigen::Vector3d> dst;
  for (size_t i = 0; i < num_coords; ++i) {
    src.emplace_back(i, i + 2, i * i);
    dst.push_back(gt_tgt_from_src * src.back());
  }

  Sim3d tgt_from_src;
  EXPECT_TRUE(EstimateSim3d(src, dst, tgt_from_src));
  EXPECT_NEAR(gt_tgt_from_src.scale, tgt_from_src.scale, 1e-6);
  EXPECT_LT(gt_tgt_from_src.rotation.angularDistance(tgt_from_src.rotation),
            1e-6);
  EXPECT_LT((gt_tgt_from_src.translation - tgt_from_src.translation).norm(),
            1e-6);
}

TEST(Sim3d, EstimateMinimal) { TestEstimateSim3dWithNumCoords(3); }

TEST(Sim3d, EstimateOverDetermined) { TestEstimateSim3dWithNumCoords(100); }

TEST(Sim3d, EstimateDegenerate) {
  std::vector<Eigen::Vector3d> invalid_src_dst(3, Eigen::Vector3d::Zero());
  Sim3d tgt_from_src;
  EXPECT_FALSE(EstimateSim3d(invalid_src_dst, invalid_src_dst, tgt_from_src));
}

}  // namespace
}  // namespace colmap
