/*
 * Copyright(C) 1999-2020 National Technology & Engineering Solutions
 * of Sandia, LLC (NTESS).  Under the terms of Contract DE-NA0003525 with
 * NTESS, the U.S. Government retains certain rights in this software.
 *
 * See packages/seacas/LICENSE for details
 */

#include "refine_map.h" // for refine_vdata
#include <stdio.h>      // for NULL

void update_mesh_vdata(int    old_loc, /* previous node for moved vertex in moved dimension */
                       int    new_loc, /* new node for moved vertex in moved dimension */
                       int    dim,     /* dimension that was changed */
                       double ewgt,    /* weight of edge */
                       struct refine_vdata *vdata,        /* array of vertex data */
                       int                  mesh_dims[3], /* size of processor mesh */
                       int                  neighbor,     /* vertex impacted by flip */
                       int *vtx2node /* mapping from comm_graph vtxs to processors */
)
{
  struct refine_vdata *vptr          = NULL; /* correct element in vdata */
  int                  offset        = 0;    /* index into vdata array */
  int                  my_loc        = 0;    /* my location in relevant dimension */
  int                  neighbor_node = 0;    /* processor neighbor assigned to */

  neighbor_node = vtx2node[neighbor];

  if (dim == 0) {
    offset = 0;
    my_loc = neighbor_node % mesh_dims[0];
  }
  else if (dim == 1) {
    offset = mesh_dims[0] * mesh_dims[1] * mesh_dims[2];
    my_loc = (neighbor_node / mesh_dims[0]) % mesh_dims[1];
  }
  else if (dim == 2) {
    offset = 2 * mesh_dims[0] * mesh_dims[1] * mesh_dims[2];
    my_loc = neighbor_node / (mesh_dims[0] * mesh_dims[1]);
  }

  vptr = &vdata[offset + neighbor];

  /* If I'm far away from the flipped edge, I'm not effected. */
  if (!((old_loc < my_loc && new_loc < my_loc) || (old_loc > my_loc && new_loc > my_loc))) {
    if (old_loc < my_loc) { /* Old moves to the right to line up with me. */
      vptr->same += ewgt;
      vptr->below -= ewgt;
    }

    else if (old_loc > my_loc) { /* Old moves to the left to line up with me. */
      vptr->same += ewgt;
      vptr->above -= ewgt;
    }

    else if (new_loc < my_loc) { /* Old moves to the left to pass me. */
      vptr->same -= ewgt;
      vptr->below += ewgt;
    }

    else if (new_loc > my_loc) { /* Old moves to the right to pass me. */
      vptr->same -= ewgt;
      vptr->above += ewgt;
    }
  }
}