/* ----------------------------------------------------------------------
   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
   https://www.lammps.org/, Sandia National Laboratories
   LAMMPS development team: developers@lammps.org

   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 "region_block.h"

#include "domain.h"
#include "error.h"
#include "input.h"
#include "math_extra.h"
#include "variable.h"

#include <cstring>

using namespace LAMMPS_NS;

static constexpr double BIG = 1.0e20;

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

RegBlock::RegBlock(LAMMPS *lmp, int narg, char **arg) :
    Region(lmp, narg, arg), xlostr(nullptr), ylostr(nullptr), zlostr(nullptr), xhistr(nullptr),
    yhistr(nullptr), zhistr(nullptr)
{
  xlovar = xhivar = ylovar = yhivar = zlovar = zhivar = -1;

  options(narg - 8, &arg[8]);

  xlostyle = CONSTANT;
  if (strcmp(arg[2], "INF") == 0 || strcmp(arg[2], "EDGE") == 0) {
    if (domain->box_exist == 0)
      error->all(FLERR, "Cannot use region INF or EDGE when box does not exist");
    if (strcmp(arg[2], "INF") == 0)
      xlo = -BIG;
    else if (domain->triclinic == 0)
      xlo = domain->boxlo[0];
    else
      xlo = domain->boxlo_bound[0];
  } else if (utils::strmatch(arg[2], "^v_")) {
    xlostr = utils::strdup(arg[2] + 2);
    xlo = 0.0;
    xlostyle = VARIABLE;
    varshape = 1;
  } else
    xlo = xscale * utils::numeric(FLERR, arg[2], false, lmp);

  xhistyle = CONSTANT;
  if (strcmp(arg[3], "INF") == 0 || strcmp(arg[3], "EDGE") == 0) {
    if (domain->box_exist == 0)
      error->all(FLERR, "Cannot use region INF or EDGE when box does not exist");
    if (strcmp(arg[3], "INF") == 0)
      xhi = BIG;
    else if (domain->triclinic == 0)
      xhi = domain->boxhi[0];
    else
      xhi = domain->boxhi_bound[0];
  } else if (utils::strmatch(arg[3], "^v_")) {
    xhistr = utils::strdup(arg[3] + 2);
    xhi = 0.0;
    xhistyle = VARIABLE;
    varshape = 1;
  } else
    xhi = xscale * utils::numeric(FLERR, arg[3], false, lmp);

  ylostyle = CONSTANT;
  if (strcmp(arg[4], "INF") == 0 || strcmp(arg[4], "EDGE") == 0) {
    if (domain->box_exist == 0)
      error->all(FLERR, "Cannot use region INF or EDGE when box does not exist");
    if (strcmp(arg[4], "INF") == 0)
      ylo = -BIG;
    else if (domain->triclinic == 0)
      ylo = domain->boxlo[1];
    else
      ylo = domain->boxlo_bound[1];
  } else if (utils::strmatch(arg[4], "^v_")) {
    ylostr = utils::strdup(arg[4] + 2);
    ylo = 0.0;
    ylostyle = VARIABLE;
    varshape = 1;
  } else
    ylo = yscale * utils::numeric(FLERR, arg[4], false, lmp);

  yhistyle = CONSTANT;
  if (strcmp(arg[5], "INF") == 0 || strcmp(arg[5], "EDGE") == 0) {
    if (domain->box_exist == 0)
      error->all(FLERR, "Cannot use region INF or EDGE when box does not exist");
    if (strcmp(arg[5], "INF") == 0)
      yhi = BIG;
    else if (domain->triclinic == 0)
      yhi = domain->boxhi[1];
    else
      yhi = domain->boxhi_bound[1];
  } else if (utils::strmatch(arg[5], "^v_")) {
    yhistr = utils::strdup(arg[5] + 2);
    yhi = 0.0;
    yhistyle = VARIABLE;
    varshape = 1;
  } else
    yhi = yscale * utils::numeric(FLERR, arg[5], false, lmp);

  zlostyle = CONSTANT;
  if (strcmp(arg[6], "INF") == 0 || strcmp(arg[6], "EDGE") == 0) {
    if (domain->box_exist == 0)
      error->all(FLERR, "Cannot use region INF or EDGE when box does not exist");
    if (strcmp(arg[6], "INF") == 0)
      zlo = -BIG;
    else if (domain->triclinic == 0)
      zlo = domain->boxlo[2];
    else
      zlo = domain->boxlo_bound[2];
  } else if (utils::strmatch(arg[6], "^v_")) {
    zlostr = utils::strdup(arg[6] + 2);
    zlo = 0.0;
    zlostyle = VARIABLE;
    varshape = 1;
  } else
    zlo = zscale * utils::numeric(FLERR, arg[6], false, lmp);

  zhistyle = CONSTANT;
  if (strcmp(arg[7], "INF") == 0 || strcmp(arg[7], "EDGE") == 0) {
    if (domain->box_exist == 0)
      error->all(FLERR, "Cannot use region INF or EDGE when box does not exist");
    if (strcmp(arg[7], "INF") == 0)
      zhi = BIG;
    else if (domain->triclinic == 0)
      zhi = domain->boxhi[2];
    else
      zhi = domain->boxhi_bound[2];
  } else if (utils::strmatch(arg[7], "^v_")) {
    zhistr = utils::strdup(arg[7] + 2);
    zhi = 0.0;
    zhistyle = VARIABLE;
    varshape = 1;
  } else
    zhi = zscale * utils::numeric(FLERR, arg[7], false, lmp);

  if (varshape) {
    variable_check();
    RegBlock::shape_update();
  }

  // error check

  if (xlo > xhi) error->all(FLERR, "Illegal region block xlo: {} >= xhi: {}", xlo, xhi);
  if (ylo > yhi) error->all(FLERR, "Illegal region block ylo: {} >= yhi: {}", ylo, yhi);
  if (zlo > zhi) error->all(FLERR, "Illegal region block zlo: {} >= zhi: {}", zlo, zhi);

  // extent of block

  if (interior && !dynamic && !varshape) {
    bboxflag = 1;
    extent_xlo = xlo;
    extent_xhi = xhi;
    extent_ylo = ylo;
    extent_yhi = yhi;
    extent_zlo = zlo;
    extent_zhi = zhi;
  } else
    bboxflag = 0;

  // particle could be close to all 6 planes
  // particle can only touch 3 planes

  cmax = 6;
  contact = new Contact[cmax];
  if (interior)
    tmax = 3;
  else
    tmax = 1;

  // open face data structs

  face[0][0] = -1.0;
  face[0][1] = 0.0;
  face[0][2] = 0.0;
  face[1][0] = 1.0;
  face[1][1] = 0.0;
  face[1][2] = 0.0;
  face[2][0] = 0.0;
  face[2][1] = -1.0;
  face[2][2] = 0.0;
  face[3][0] = 0.0;
  face[3][1] = 1.0;
  face[3][2] = 0.0;
  face[4][0] = 0.0;
  face[4][1] = 0.0;
  face[4][2] = -1.0;
  face[5][0] = 0.0;
  face[5][1] = 0.0;
  face[5][2] = 1.0;

  // face[0]

  corners[0][0][0] = xlo;
  corners[0][0][1] = ylo;
  corners[0][0][2] = zlo;
  corners[0][1][0] = xlo;
  corners[0][1][1] = ylo;
  corners[0][1][2] = zhi;
  corners[0][2][0] = xlo;
  corners[0][2][1] = yhi;
  corners[0][2][2] = zhi;
  corners[0][3][0] = xlo;
  corners[0][3][1] = yhi;
  corners[0][3][2] = zlo;

  // face[1]

  corners[1][0][0] = xhi;
  corners[1][0][1] = ylo;
  corners[1][0][2] = zlo;
  corners[1][1][0] = xhi;
  corners[1][1][1] = ylo;
  corners[1][1][2] = zhi;
  corners[1][2][0] = xhi;
  corners[1][2][1] = yhi;
  corners[1][2][2] = zhi;
  corners[1][3][0] = xhi;
  corners[1][3][1] = yhi;
  corners[1][3][2] = zlo;

  // face[2]

  MathExtra::copy3(corners[0][0], corners[2][0]);
  MathExtra::copy3(corners[1][0], corners[2][1]);
  MathExtra::copy3(corners[1][1], corners[2][2]);
  MathExtra::copy3(corners[0][1], corners[2][3]);

  // face[3]

  MathExtra::copy3(corners[0][3], corners[3][0]);
  MathExtra::copy3(corners[0][2], corners[3][1]);
  MathExtra::copy3(corners[1][2], corners[3][2]);
  MathExtra::copy3(corners[1][3], corners[3][3]);

  // face[4]

  MathExtra::copy3(corners[0][0], corners[4][0]);
  MathExtra::copy3(corners[0][3], corners[4][1]);
  MathExtra::copy3(corners[1][3], corners[4][2]);
  MathExtra::copy3(corners[1][0], corners[4][3]);

  // face[5]

  MathExtra::copy3(corners[0][1], corners[5][0]);
  MathExtra::copy3(corners[1][1], corners[5][1]);
  MathExtra::copy3(corners[1][2], corners[5][2]);
  MathExtra::copy3(corners[0][2], corners[5][3]);
}

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

RegBlock::~RegBlock()
{
  if (copymode) return;

  delete[] xlostr;
  delete[] xhistr;
  delete[] ylostr;
  delete[] yhistr;
  delete[] zlostr;
  delete[] zhistr;
  delete[] contact;
}

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

void RegBlock::init()
{
  Region::init();
  if (varshape) variable_check();
}

/* ----------------------------------------------------------------------
   inside = 1 if x,y,z is inside or on surface
   inside = 0 if x,y,z is outside and not on surface
------------------------------------------------------------------------- */

int RegBlock::inside(double x, double y, double z)
{
  if (x >= xlo && x <= xhi && y >= ylo && y <= yhi && z >= zlo && z <= zhi) return 1;
  return 0;
}

/* ----------------------------------------------------------------------
   contact if 0 <= x < cutoff from one or more inner surfaces of block
   can be one contact for each of 6 faces
   no contact if outside (possible if called from union/intersect)
   delxyz = vector from nearest point on block to x
------------------------------------------------------------------------- */

int RegBlock::surface_interior(double *x, double cutoff)
{
  double delta;

  // x is exterior to block

  if (x[0] < xlo || x[0] > xhi || x[1] < ylo || x[1] > yhi || x[2] < zlo || x[2] > zhi) return 0;

  // x is interior to block or on its surface

  int n = 0;

  delta = x[0] - xlo;
  if (delta < cutoff && !open_faces[0]) {
    contact[n].r = delta;
    contact[n].delx = delta;
    contact[n].dely = contact[n].delz = 0.0;
    contact[n].radius = 0;
    contact[n].iwall = 0;
    n++;
  }
  delta = xhi - x[0];
  if (delta < cutoff && !open_faces[1]) {
    contact[n].r = delta;
    contact[n].delx = -delta;
    contact[n].dely = contact[n].delz = 0.0;
    contact[n].radius = 0;
    contact[n].iwall = 1;
    n++;
  }

  delta = x[1] - ylo;
  if (delta < cutoff && !open_faces[2]) {
    contact[n].r = delta;
    contact[n].dely = delta;
    contact[n].delx = contact[n].delz = 0.0;
    contact[n].radius = 0;
    contact[n].iwall = 2;
    n++;
  }
  delta = yhi - x[1];
  if (delta < cutoff && !open_faces[3]) {
    contact[n].r = delta;
    contact[n].dely = -delta;
    contact[n].delx = contact[n].delz = 0.0;
    contact[n].radius = 0;
    contact[n].iwall = 3;
    n++;
  }

  delta = x[2] - zlo;
  if (delta < cutoff && !open_faces[4]) {
    contact[n].r = delta;
    contact[n].delz = delta;
    contact[n].delx = contact[n].dely = 0.0;
    contact[n].radius = 0;
    contact[n].iwall = 4;
    n++;
  }
  delta = zhi - x[2];
  if (delta < cutoff && !open_faces[5]) {
    contact[n].r = delta;
    contact[n].delz = -delta;
    contact[n].delx = contact[n].dely = 0.0;
    contact[n].radius = 0;
    contact[n].iwall = 5;
    n++;
  }

  return n;
}

/* ----------------------------------------------------------------------
   one contact if 0 <= x < cutoff from outer surface of block
   no contact if inside (possible if called from union/intersect)
   delxyz = vector from nearest point on block to x
------------------------------------------------------------------------- */

int RegBlock::surface_exterior(double *x, double cutoff)
{
  double xp, yp, zp;
  double xc, yc, zc, dist, mindist;

  // x is far enough from block that there is no contact
  // x is interior to block

  if (x[0] <= xlo - cutoff || x[0] >= xhi + cutoff || x[1] <= ylo - cutoff ||
      x[1] >= yhi + cutoff || x[2] <= zlo - cutoff || x[2] >= zhi + cutoff)
    return 0;
  if (x[0] > xlo && x[0] < xhi && x[1] > ylo && x[1] < yhi && x[2] > zlo && x[2] < zhi) return 0;

  // x is exterior to block or on its surface
  // xp,yp,zp = point on surface of block that x is closest to
  //            could be edge or corner pt of block
  // do not add contact point if r >= cutoff

  if (!openflag) {
    if (x[0] < xlo)
      xp = xlo;
    else if (x[0] > xhi)
      xp = xhi;
    else
      xp = x[0];
    if (x[1] < ylo)
      yp = ylo;
    else if (x[1] > yhi)
      yp = yhi;
    else
      yp = x[1];
    if (x[2] < zlo)
      zp = zlo;
    else if (x[2] > zhi)
      zp = zhi;
    else
      zp = x[2];
  } else {
    mindist = BIG;
    for (int i = 0; i < 6; i++) {
      if (open_faces[i]) continue;
      dist = find_closest_point(i, x, xc, yc, zc);
      if (dist < mindist) {
        xp = xc;
        yp = yc;
        zp = zc;
        mindist = dist;
      }
    }
  }

  add_contact(0, x, xp, yp, zp);
  contact[0].iwall = 0;
  if (contact[0].r < cutoff) return 1;
  return 0;
}

/* ----------------------------------------------------------------------
    change region shape via variable evaluation
------------------------------------------------------------------------- */

void RegBlock::shape_update()    // addition
{
  if (xlostyle == VARIABLE) xlo = xscale * input->variable->compute_equal(xlovar);
  if (xhistyle == VARIABLE) xhi = xscale * input->variable->compute_equal(xhivar);
  if (ylostyle == VARIABLE) ylo = yscale * input->variable->compute_equal(ylovar);
  if (yhistyle == VARIABLE) yhi = yscale * input->variable->compute_equal(yhivar);
  if (zlostyle == VARIABLE) zlo = zscale * input->variable->compute_equal(zlovar);
  if (zhistyle == VARIABLE) zhi = zscale * input->variable->compute_equal(zhivar);

  if (xlo > xhi || ylo > yhi || zlo > zhi)
    error->one(FLERR, "Variable evaluation in region gave bad value");

  // face[0]

  corners[0][0][0] = xlo;
  corners[0][0][1] = ylo;
  corners[0][0][2] = zlo;
  corners[0][1][0] = xlo;
  corners[0][1][1] = ylo;
  corners[0][1][2] = zhi;
  corners[0][2][0] = xlo;
  corners[0][2][1] = yhi;
  corners[0][2][2] = zhi;
  corners[0][3][0] = xlo;
  corners[0][3][1] = yhi;
  corners[0][3][2] = zlo;

  // face[1]

  corners[1][0][0] = xhi;
  corners[1][0][1] = ylo;
  corners[1][0][2] = zlo;
  corners[1][1][0] = xhi;
  corners[1][1][1] = ylo;
  corners[1][1][2] = zhi;
  corners[1][2][0] = xhi;
  corners[1][2][1] = yhi;
  corners[1][2][2] = zhi;
  corners[1][3][0] = xhi;
  corners[1][3][1] = yhi;
  corners[1][3][2] = zlo;

  // face[2]

  MathExtra::copy3(corners[0][0], corners[2][0]);
  MathExtra::copy3(corners[1][0], corners[2][1]);
  MathExtra::copy3(corners[1][1], corners[2][2]);
  MathExtra::copy3(corners[0][1], corners[2][3]);

  // face[3]

  MathExtra::copy3(corners[0][3], corners[3][0]);
  MathExtra::copy3(corners[0][2], corners[3][1]);
  MathExtra::copy3(corners[1][2], corners[3][2]);
  MathExtra::copy3(corners[1][3], corners[3][3]);

  // face[4]

  MathExtra::copy3(corners[0][0], corners[4][0]);
  MathExtra::copy3(corners[0][3], corners[4][1]);
  MathExtra::copy3(corners[1][3], corners[4][2]);
  MathExtra::copy3(corners[1][0], corners[4][3]);

  // face[5]

  MathExtra::copy3(corners[0][1], corners[5][0]);
  MathExtra::copy3(corners[1][1], corners[5][1]);
  MathExtra::copy3(corners[1][2], corners[5][2]);
  MathExtra::copy3(corners[0][2], corners[5][3]);
}

/* ----------------------------------------------------------------------
   error check on existence of variable
------------------------------------------------------------------------- */

void RegBlock::variable_check()    // addition
{
  if (xlostyle == VARIABLE) {
    xlovar = input->variable->find(xlostr);
    if (xlovar < 0) error->all(FLERR, "Variable {} for region block does not exist", xlostr);
    if (!input->variable->equalstyle(xlovar))
      error->all(FLERR, "Variable {} for region block is invalid style", xlostr);
  }
  if (xhistyle == VARIABLE) {
    xhivar = input->variable->find(xhistr);
    if (xhivar < 0) error->all(FLERR, "Variable {} for region block does not exist", xhistr);
    if (!input->variable->equalstyle(xhivar))
      error->all(FLERR, "Variable {} for region block is invalid style", xhistr);
  }

  if (ylostyle == VARIABLE) {
    ylovar = input->variable->find(ylostr);
    if (ylovar < 0) error->all(FLERR, "Variable {} for region block does not exist", ylostr);
    if (!input->variable->equalstyle(ylovar))
      error->all(FLERR, "Variable {} for region block is invalid style", ylostr);
  }
  if (yhistyle == VARIABLE) {
    yhivar = input->variable->find(yhistr);
    if (yhivar < 0) error->all(FLERR, "Variable {} for region block does not exist", yhistr);
    if (!input->variable->equalstyle(yhivar))
      error->all(FLERR, "Variable {} for region block is invalid style", yhistr);
  }

  if (zlostyle == VARIABLE) {
    zlovar = input->variable->find(zlostr);
    if (zlovar < 0) error->all(FLERR, "Variable {} for region block does not exist", zlostr);
    if (!input->variable->equalstyle(zlovar))
      error->all(FLERR, "Variable {} for region block is invalid style", zlostr);
  }
  if (zhistyle == VARIABLE) {
    zhivar = input->variable->find(zhistr);
    if (zhivar < 0) error->all(FLERR, "Variable {} for region block does not exist", zhistr);
    if (!input->variable->equalstyle(zhivar))
      error->all(FLERR, "Variable {} for region block is invalid style", zhistr);
  }
}

/*------------------------------------------------------------------------
  return distance to closest point on surface I of block region
  store closest point in xc,yc,zc
--------------------------------------------------------------------------*/

double RegBlock::find_closest_point(int i, double *x, double &xc, double &yc, double &zc)
{
  double dot, d2, d2min;
  double xr[3], xproj[3], p[3];

  xr[0] = x[0] - corners[i][0][0];
  xr[1] = x[1] - corners[i][0][1];
  xr[2] = x[2] - corners[i][0][2];
  dot = face[i][0] * xr[0] + face[i][1] * xr[1] + face[i][2] * xr[2];
  xproj[0] = xr[0] - dot * face[i][0];
  xproj[1] = xr[1] - dot * face[i][1];
  xproj[2] = xr[2] - dot * face[i][2];

  d2min = BIG;

  // check if point projects inside of face

  if (inside_face(xproj, i)) {
    d2 = d2min = dot * dot;
    xc = xproj[0] + corners[i][0][0];
    yc = xproj[1] + corners[i][0][1];
    zc = xproj[2] + corners[i][0][2];

    // check each edge

  } else {
    point_on_line_segment(corners[i][0], corners[i][1], x, p);
    d2 = (p[0] - x[0]) * (p[0] - x[0]) + (p[1] - x[1]) * (p[1] - x[1]) +
        (p[2] - x[2]) * (p[2] - x[2]);
    if (d2 < d2min) {
      d2min = d2;
      xc = p[0];
      yc = p[1];
      zc = p[2];
    }

    point_on_line_segment(corners[i][1], corners[i][2], x, p);
    d2 = (p[0] - x[0]) * (p[0] - x[0]) + (p[1] - x[1]) * (p[1] - x[1]) +
        (p[2] - x[2]) * (p[2] - x[2]);
    if (d2 < d2min) {
      d2min = d2;
      xc = p[0];
      yc = p[1];
      zc = p[2];
    }

    point_on_line_segment(corners[i][2], corners[i][3], x, p);
    d2 = (p[0] - x[0]) * (p[0] - x[0]) + (p[1] - x[1]) * (p[1] - x[1]) +
        (p[2] - x[2]) * (p[2] - x[2]);
    if (d2 < d2min) {
      d2min = d2;
      xc = p[0];
      yc = p[1];
      zc = p[2];
    }

    point_on_line_segment(corners[i][3], corners[i][0], x, p);
    d2 = (p[0] - x[0]) * (p[0] - x[0]) + (p[1] - x[1]) * (p[1] - x[1]) +
        (p[2] - x[2]) * (p[2] - x[2]);
    if (d2 < d2min) {
      d2min = d2;
      xc = p[0];
      yc = p[1];
      zc = p[2];
    }
  }

  return d2min;
}

/*------------------------------------------------------------------------
  determine if projected point is inside given face of the block
--------------------------------------------------------------------------*/

int RegBlock::inside_face(double *xproj, int iface)
{
  if (iface < 2) {
    if (xproj[1] > 0 && (xproj[1] < yhi - ylo) && xproj[2] > 0 && (xproj[2] < zhi - zlo)) return 1;
  } else if (iface < 4) {
    if (xproj[0] > 0 && (xproj[0] < (xhi - xlo)) && xproj[2] > 0 && (xproj[2] < (zhi - zlo)))
      return 1;
  } else {
    if (xproj[0] > 0 && xproj[0] < (xhi - xlo) && xproj[1] > 0 && xproj[1] < (yhi - ylo)) return 1;
  }

  return 0;
}
