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 * Author: Eitan Marder-Eppstein
 *         David V. Lu!!
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#ifndef ROBOT_COSTMAP_2D_VOXEL_LAYER_H_
#define ROBOT_COSTMAP_2D_VOXEL_LAYER_H_

#include <robot_costmap_2d/layer.h>
#include <robot_costmap_2d/layered_costmap.h>
#include <robot_costmap_2d/observation_buffer.h>
#include <robot_costmap_2d/voxel_grid.h>
#include <robot_nav_msgs/OccupancyGrid.h>
#include <robot_sensor_msgs/LaserScan.h>
#include <robot_laser_geometry/laser_geometry.hpp>
#include <robot_sensor_msgs/PointCloud.h>
#include <robot_sensor_msgs/PointCloud2.h>
#include <robot_sensor_msgs/point_cloud_conversion.h>
#include <robot_costmap_2d/obstacle_layer.h>
#include <robot_voxel_grid/voxel_grid.h>

#include <limits>
#include <vector>

namespace robot_costmap_2d
{

class VoxelLayer : public ObstacleLayer
{
public:
  VoxelLayer() :
      robot_voxel_grid_(0, 0, 0)
  {
    costmap_ = NULL;  // this is the unsigned char* member of parent class's parent class Costmap2D.
  }

  virtual ~VoxelLayer();

  virtual void onInitialize();
  virtual void updateBounds(double robot_x, double robot_y, double robot_yaw, double* min_x, double* min_y,
                            double* max_x, double* max_y);

  void updateOrigin(double new_origin_x, double new_origin_y);
  bool isDiscretized()
  {
    return true;
  }
  virtual void matchSize();
  virtual void reset();

  LayerType getType() const override
  {
      return LayerType::VOXEL_LAYER;
  }

protected:

  virtual void resetMaps();

private:
  bool getParams(const std::string& config_file_name, robot::NodeHandle &nh);
  void clearNonLethal(double wx, double wy, double w_size_x, double w_size_y, bool clear_no_info);
  virtual void raytraceFreespace(const robot_costmap_2d::Observation& clearing_observation, double* min_x, double* min_y,
                                 double* max_x, double* max_y);
  // bool raytraceDepthFrustum(double* min_x, double* min_y, double* max_x, double* max_y);
  bool raytraceDepthFrustum(const robot_costmap_2d::DepthCameraObservation& observation,
                            double* min_x, double* min_y, double* max_x, double* max_y);
  bool readDepthMeters(const robot_sensor_msgs::Image& depth, unsigned int u, unsigned int v,
                       double& depth_m, bool& is_valid) const;
  /// True when the invalid pixel at (u, v) is an isolated hole surrounded by
  /// valid returns (a flying pixel, safe to clear), false when it belongs to a
  /// structurally invalid region such as the stereo no-disparity strip on the
  /// left image edge (no free-space evidence, must be left untouched).
  bool invalidPixelIsIsolated(const robot_sensor_msgs::Image& depth,
                              unsigned int u, unsigned int v) const;
  void updateDepthRayCache(unsigned int width, unsigned int height, unsigned int pixel_step,
                           double fx, double fy, double cx, double cy);
  bool clipRaytraceEndpoint(double ox, double oy, double oz, double& wx, double& wy, double& wz);
  bool clearVoxelRay(double ox, double oy, double oz, double wx, double wy, double wz,
                     double raytrace_range, unsigned int cell_raytrace_range,
                     double* min_x, double* min_y, double* max_x, double* max_y);
  bool clearDepthColumns(double ox, double oy, double cover_distance, double far_distance,
                         double min_range, double max_range, double skip_dist,
                         double* min_x, double* min_y, double* max_x, double* max_y);
  bool clipColumnSegment(double& sx, double& sy, double& ex, double& ey) const;


  bool publish_voxel_;
  robot_voxel_grid::VoxelGrid robot_voxel_grid_;
  double z_resolution_, origin_z_;
  /// Scratch for the full-column clearing pass (config lives per observation
  /// source in DepthFrustumConfig): per depth-image pixel column, the nearest
  /// return inside the obstacle height band certifies "no obstacle in this
  /// direction closer than d". Cells along that 2D beam get their whole voxel
  /// column cleared, removing marked voxels the per-pixel 3D rays cannot
  /// reach (above the vertical FOV at close range).
  struct DepthColumnStat
  {
    double min_band_dist = -1.0;  ///< horizontal distance of nearest in-band return; < 0 = none
    double azimuth = 0.0;         ///< beam direction in the global frame
    double best_row_delta = std::numeric_limits<double>::infinity();
    bool has_ray = false;            ///< column had at least one readable pixel
    bool has_valid_return = false;   ///< column had at least one valid depth measurement
  };
  std::vector<DepthColumnStat> depth_column_stats_;
  unsigned int unknown_threshold_, mark_threshold_, size_z_;
  robot_sensor_msgs::PointCloud clearing_endpoints_;
  std::vector<unsigned char> rolling_costmap_scratch_;
  std::vector<unsigned int> rolling_voxel_scratch_;

  struct DepthRay
  {
    unsigned int u;
    unsigned int v;
    unsigned int col;  ///< pixel-column index in the cache (border column included)
    double x;
    double y;
    double z;
  };
  std::vector<DepthRay> depth_ray_cache_;
  unsigned int cached_column_count_ = 0;
  unsigned int cached_depth_width_ = 0;
  unsigned int cached_depth_height_ = 0;
  unsigned int cached_depth_pixel_step_ = 0;
  double cached_fx_ = 0.0;
  double cached_fy_ = 0.0;
  double cached_cx_ = 0.0;
  double cached_cy_ = 0.0;

  inline bool worldToMap3DFloat(double wx, double wy, double wz, double& mx, double& my, double& mz)
  {
    if (wx < origin_x_ || wy < origin_y_ || wz < origin_z_)
      return false;
    mx = ((wx - origin_x_) / resolution_);
    my = ((wy - origin_y_) / resolution_);
    mz = ((wz - origin_z_) / z_resolution_);
    if (mx < size_x_ && my < size_y_ && mz < size_z_)
      return true;

    return false;
  }

  inline bool worldToMap3D(double wx, double wy, double wz, unsigned int& mx, unsigned int& my, unsigned int& mz)
  {
    if (wx < origin_x_ || wy < origin_y_ || wz < origin_z_)
      return false;

    mx = (int)((wx - origin_x_) / resolution_);
    my = (int)((wy - origin_y_) / resolution_);
    mz = (int)((wz - origin_z_) / z_resolution_);

    if (mx < size_x_ && my < size_y_ && mz < size_z_)
      return true;

    return false;
  }

  inline void mapToWorld3D(unsigned int mx, unsigned int my, unsigned int mz, double& wx, double& wy, double& wz)
  {
    // returns the center point of the cell
    wx = origin_x_ + (mx + 0.5) * resolution_;
    wy = origin_y_ + (my + 0.5) * resolution_;
    wz = origin_z_ + (mz + 0.5) * z_resolution_;
  }

  inline double dist(double x0, double y0, double z0, double x1, double y1, double z1)
  {
    return sqrt((x1 - x0) * (x1 - x0) + (y1 - y0) * (y1 - y0) + (z1 - z0) * (z1 - z0));
  }
};

}  // namespace robot_costmap_2d

#endif  // ROBOT_COSTMAP_2D_VOXEL_LAYER_H_