// Gmsh - Copyright (C) 1997-2025 C. Geuzaine, J.-F. Remacle
//
// See the LICENSE.txt file in the Gmsh root directory for license information.
// Please report all issues on https://gitlab.onelab.info/gmsh/gmsh/issues.

#ifndef OCTREE_INTERNALS_H
#define OCTREE_INTERNALS_H

#include <vector>

// file of function prototypes and macro constants
typedef void (*BBFunction)(void *, double *, double *);
typedef int (*InEleFunction)(void *, double *);
typedef void (*CentroidFunction)(void *, double *);

// structure for list of elements in an octant
typedef struct elem {
  void *region; // the pointer to a mesh Db region
  double centroid[3]; // centroid of element bounding box inside of the octant
  double minPt[3]; // corner of element bounding box nearest the origin
  double maxPt[3]; // corner of elem bound box furthest from the origin
  struct elem *next; // link to next item in list, NULL if end
} Elem;
typedef Elem *ELink;

// stucture for octant buckets
struct bucket {
  double minPt[3]; //  the point with the smallest coordinates
  double maxPt[3]; //  the point with the biggest coordinates
  int numElements; // number of elements contained by bucket
  int precision; // the level of precision of the bucket
  ELink lhead; // list of elements in bucket, if NULL -> no elements
  std::vector<void *> listBB; // list of elements in bucket by Bounding Box
  struct bucket *next; // link to ragged digit extensions to bucket array
  struct bucket *parent; // link to the parent bucket
};
typedef struct bucket octantBucket;

// structure for global information and requirment
struct global {
  int numBuckets; // number of octant buckets in initial grid array
  int maxElements; // max. number of elements allowed in an octant
  int maxPrecision; // current maximum octant precision for model
  double origin[3]; // smallest x,y, z of model's bounding box
  double size[3]; // size in x, y, z of model bounding box
  void *ptrToPrevElement;
  std::vector<void *> listAllElements;
};
typedef struct global globalInfo;

class Octree {
public:
  globalInfo *info;
  octantBucket *root;
  BBFunction function_BB;
  InEleFunction function_inElement;
  CentroidFunction function_centroid;
};

void refineOctants(octantBucket *buckets, globalInfo *globalPara);

int addElement2Bucket(octantBucket *bucket, void *element, double *minBB,
                      double *maxBB, double *ele_centroid,
                      globalInfo *globalPara);
int subdivideOctantBucket(octantBucket *bucket, globalInfo *globalPara);
int initializeOctantBuckets(double *orig, double *size, int maxElem,
                            octantBucket **buckets, globalInfo **globalPara);
int checkElementInBucket(octantBucket *bucket, void *element);
octantBucket *findElementBucket(octantBucket *buckets, double *pt);
void *searchElement(octantBucket *buckets, double *pt, globalInfo *globalPara,
                    BBFunction BBElement, InEleFunction xyzInElement);
int xyzInElementBB(double *xyz, void *region, BBFunction BBElement);
void insertOneBB(void *, double *, double *, octantBucket *);
void *searchAllElements(octantBucket *_buckets_head, double *_pt,
                        globalInfo *_globalPara, BBFunction BBElement,
                        InEleFunction xyzInElement,
                        std::vector<void *> *_elements);

#endif
