// Copyright (c), ETH Zurich and UNC Chapel Hill.
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//
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// modification, are permitted provided that the following conditions are met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//
//     * Redistributions in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in the
//       documentation and/or other materials provided with the distribution.
//
//     * Neither the name of ETH Zurich and UNC Chapel Hill nor the names of
//       its contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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#pragma once

#include "colmap/util/eigen_alignment.h"

#include <filesystem>
#include <vector>

#include <Eigen/Core>

namespace colmap {
namespace mvs {

// List of geometrically consistent images, in the following format:
//
//    r_1, c_1, N_1, i_11, i_12, ..., i_1N_1,
//    r_2, c_2, N_2, i_21, i_22, ..., i_2N_2, ...
//
// where r, c are the row and column image coordinates of the pixel,
// N is the number of consistent images, followed by the N image indices.
// Note that only pixels are listed which are not filtered and that the
// consistency graph is only filled if filtering is enabled.
class ConsistencyGraph {
 public:
  ConsistencyGraph();
  ConsistencyGraph(size_t width, size_t height, const std::vector<int>& data);

  size_t GetNumBytes() const;

  void GetImageIdxs(int row,
                    int col,
                    int* num_images,
                    const int** image_idxs) const;

  void Read(const std::filesystem::path& path);
  void Write(const std::filesystem::path& path) const;

 private:
  void InitializeMap(size_t width, size_t height);

  const static int kNoConsistentImageIds;
  std::vector<int> data_;
  Eigen::MatrixXi map_;
};

}  // namespace mvs
}  // namespace colmap
