// clang-format off
/* ----------------------------------------------------------------------
   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
   https://www.lammps.org/, Sandia National Laboratories
   Steve Plimpton, sjplimp@sandia.gov

   Copyright (2003) Sandia Corporation.  Under the terms of Contract
   DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
   certain rights in this software.  This software is distributed under
   the GNU General Public License.

   See the README file in the top-level LAMMPS directory.
------------------------------------------------------------------------- */

#include "nstencil_half_multi_3d.h"
#include "neighbor.h"
#include "neigh_list.h"
#include "nbin.h"
#include "memory.h"
#include "atom.h"
#include <math.h>

using namespace LAMMPS_NS;

/* ---------------------------------------------------------------------- */

NStencilHalfMulti3d::NStencilHalfMulti3d(LAMMPS *lmp) :
  NStencil(lmp) {}

/* ---------------------------------------------------------------------- */

void NStencilHalfMulti3d::set_stencil_properties()
{
  int n = ncollections;
  int i, j;

  // Cross collections: use full stencil, looking one way through hierarchy
  // smaller -> larger => use full stencil in larger bin
  // larger -> smaller => no nstencil required
  // If cut offs are same, use half stencil

  for (i = 0; i < n; i++) {
    for (j = 0; j < n; j++) {
      if(cutcollectionsq[i][i] > cutcollectionsq[j][j]) continue;

      flag_skip_multi[i][j] = 0;

      if(cutcollectionsq[i][i] == cutcollectionsq[j][j]){
        flag_half_multi[i][j] = 1;
        bin_collection_multi[i][j] = i;
      } else {
        flag_half_multi[i][j] = 0;
        bin_collection_multi[i][j] = j;
      }
    }
  }
}

/* ----------------------------------------------------------------------
   create stencils based on bin geometry and cutoff
------------------------------------------------------------------------- */

void NStencilHalfMulti3d::create()
{
  int icollection, jcollection, bin_collection, i, j, k, ns;
  int n = ncollections;
  double cutsq;


  for (icollection = 0; icollection < n; icollection++) {
    for (jcollection = 0; jcollection < n; jcollection++) {
      if (flag_skip_multi[icollection][jcollection]) {
        nstencil_multi[icollection][jcollection] = 0;
        continue;
      }

      ns = 0;

      sx = stencil_sx_multi[icollection][jcollection];
      sy = stencil_sy_multi[icollection][jcollection];
      sz = stencil_sz_multi[icollection][jcollection];

      mbinx = stencil_mbinx_multi[icollection][jcollection];
      mbiny = stencil_mbiny_multi[icollection][jcollection];
      mbinz = stencil_mbinz_multi[icollection][jcollection];

      bin_collection = bin_collection_multi[icollection][jcollection];

      cutsq = cutcollectionsq[icollection][jcollection];

      if (flag_half_multi[icollection][jcollection]) {
        for (k = 0; k <= sz; k++)
          for (j = -sy; j <= sy; j++)
            for (i = -sx; i <= sx; i++)
	          if (k > 0 || j > 0 || (j == 0 && i > 0)) {
	            if (bin_distance_multi(i,j,k,bin_collection) < cutsq)
	              stencil_multi[icollection][jcollection][ns++] =
                          k*mbiny*mbinx + j*mbinx + i;
	          }
      } else {
        for (k = -sz; k <= sz; k++)
          for (j = -sy; j <= sy; j++)
            for (i = -sx; i <= sx; i++)
	          if (bin_distance_multi(i,j,k,bin_collection) < cutsq)
	            stencil_multi[icollection][jcollection][ns++] =
                        k*mbiny*mbinx + j*mbinx + i;
      }

      nstencil_multi[icollection][jcollection] = ns;
    }
  }
}