/*============================================================================
 * General-purpose user-defined functions called before time stepping, at
 * the end of each time step, and after time-stepping.
 *
 * These can be used for operations which do not fit naturally in any other
 * dedicated user function.
 *============================================================================*/

/* code_saturne version 8.0 */

/*
  This file is part of code_saturne, a general-purpose CFD tool.

  Copyright (C) 1998-2023 EDF S.A.

  This program is free software; you can redistribute it and/or modify it under
  the terms of the GNU General Public License as published by the Free Software
  Foundation; either version 2 of the License, or (at your option) any later
  version.

  This program is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  details.

  You should have received a copy of the GNU General Public License along with
  this program; if not, write to the Free Software Foundation, Inc., 51 Franklin
  Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/

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

#include "cs_defs.h"

/*----------------------------------------------------------------------------
 * Standard C library headers
 *----------------------------------------------------------------------------*/

#include <assert.h>
#include <math.h>
#include <stdio.h>

#if defined(HAVE_MPI)
#include <mpi.h>
#endif

/*----------------------------------------------------------------------------
 * Local headers
 *----------------------------------------------------------------------------*/

#include "cs_headers.h"

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

BEGIN_C_DECLS

/*----------------------------------------------------------------------------*/
/*!
 * \file cs_user_extra_operations-boundary_forces.c
 *
 * \brief This function is called at the end of each time step, and has a very
 * general purpose (i.e. anything that does not have another dedicated
 * user function).
 *
 * This is an example of cs_user_extra_operations.c which computes the total
 * force on a boundary zone.
 *
 */
/*----------------------------------------------------------------------------*/

/*============================================================================
 * User function definitions
 *============================================================================*/

/*----------------------------------------------------------------------------*/
/*!
 * \brief This function is called at the end of each time step.
 *
 * It has a very general purpose, although it is recommended to handle
 * mainly postprocessing or data-extraction type operations.
 *
 * \param[in, out]  domain   pointer to a cs_domain_t structure
 */
/*----------------------------------------------------------------------------*/

static cs_time_plot_t *_boundary_force_plot = NULL;

void
cs_user_extra_operations(cs_domain_t     *domain)
{
  const cs_time_step_t *ts = cs_glob_time_step;
  const int n_variables = 3; // Surface force in x,y,z directions

  if (cs_glob_rank_id<1 && _boundary_force_plot == NULL){
    int                    _plot_buffer_steps = -1;
    double                 _plot_flush_wtime = 60;
    cs_time_plot_format_t  _plot_format = CS_TIME_PLOT_CSV;
    bool                   use_iteration = (ts->is_local) ? true : false;

    const char **labels;
    BFT_MALLOC(labels, n_variables + 1, const char *);
    labels[0]="force_x";
    labels[1]="force_y";
    labels[2]="force_z";
    
    _boundary_force_plot = cs_time_plot_init_probe("boundary_force",
                                                   "",
                                                   _plot_format,
                                                   use_iteration,
                                                   _plot_flush_wtime,
                                                   _plot_buffer_steps,
                                                   n_variables,
                                                   NULL,
                                                   NULL,
                                                   labels);
    BFT_FREE(labels);
  }

  {
    const cs_lnum_t n_b_faces = domain->mesh->n_b_faces;

    cs_field_t *b_forces = cs_field_by_name_try("boundary_forces");

    if (b_forces != NULL) {
      cs_real_3_t total_b_forces = {0., 0., 0.};
      cs_lnum_t n_elts, *lst_elts;
      BFT_MALLOC(lst_elts, n_b_faces, cs_lnum_t);
      cs_selector_get_b_face_list("UPPER_WALL", &n_elts, lst_elts);

      for (cs_lnum_t i_elt = 0; i_elt < n_elts; i_elt++) {
        cs_lnum_t face_id = lst_elts[i_elt];
        for (int ii = 0; ii < 3; ii++)
          total_b_forces[ii] += b_forces->val[3*face_id + ii];
      }
      BFT_FREE(lst_elts);

      /* parallel sum */
      cs_parall_sum(3, CS_DOUBLE, total_b_forces);
      bft_printf(" Total Axial Force: %f\n", total_b_forces[0]);

      if (cs_glob_rank_id<1){
        cs_time_plot_vals_write(_boundary_force_plot,
                                ts->nt_cur,
                                ts->t_cur,
                                n_variables,
                                total_b_forces);
      }
    }

  }

  {
    const cs_lnum_t n_b_faces = domain->mesh->n_b_faces;
    const cs_real_t *b_f_face_normal =
      domain->mesh_quantities->b_f_face_normal;

    cs_real_3_t total_b_p_forces = {0., 0., 0.};
    cs_lnum_t n_elts, *lst_elts;
    BFT_MALLOC(lst_elts, n_b_faces, cs_lnum_t);
    cs_selector_get_b_face_list("UPPER_WALL", &n_elts, lst_elts);

    /* compute static pressure on selected boundary faces */
    cs_real_t *p_b_val;
    BFT_MALLOC(p_b_val, n_elts, cs_real_t);
    cs_post_b_pressure(n_elts, lst_elts, p_b_val);

    for (cs_lnum_t i_elt = 0; i_elt < n_elts; i_elt++) {
      cs_lnum_t face_id = lst_elts[i_elt];
      for (int ii = 0; ii < 3; ii++)
        total_b_p_forces[ii] += p_b_val[i_elt]*b_f_face_normal[3*face_id+ii];
    }
    BFT_FREE(lst_elts);
    BFT_FREE(p_b_val);

    /* parallel sum */
    cs_parall_sum(3, CS_DOUBLE, total_b_p_forces);
    bft_printf(" Total Axial Pressure Force: %f\n", total_b_p_forces[0]);
  }

}

END_C_DECLS