/*
 * 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.
 *
 * The Original Code is Copyright (C) 2019 Blender Foundation.
 * All rights reserved.
 */

/** \file
 * \ingroup edmesh
 *
 * Utility functions for merging geometry once transform has finished:
 *
 * - #EDBM_automerge
 * - #EDBM_automerge_and_split
 */

#include "BKE_editmesh.h"

#include "DNA_object_types.h"

#include "ED_mesh.h"

#include "tools/bmesh_intersect_edges.h"

//#define DEBUG_TIME
#ifdef DEBUG_TIME
#  include "PIL_time.h"
#endif

/* use bmesh operator flags for a few operators */
#define BMO_ELE_TAG 1

/* -------------------------------------------------------------------- */
/** \name Auto-Merge Selection
 *
 * Used after transform operations.
 * \{ */

void EDBM_automerge(Object *obedit, bool update, const char hflag, const float dist)
{
  BMEditMesh *em = BKE_editmesh_from_object(obedit);
  BMesh *bm = em->bm;
  int totvert_prev = bm->totvert;

  BMOperator findop, weldop;

  /* Search for doubles among all vertices, but only merge non-VERT_KEEP
   * vertices into VERT_KEEP vertices. */
  BMO_op_initf(bm,
               &findop,
               BMO_FLAG_DEFAULTS,
               "find_doubles verts=%av keep_verts=%Hv dist=%f",
               hflag,
               dist);

  BMO_op_exec(bm, &findop);

  /* weld the vertices */
  BMO_op_init(bm, &weldop, BMO_FLAG_DEFAULTS, "weld_verts");
  BMO_slot_copy(&findop, slots_out, "targetmap.out", &weldop, slots_in, "targetmap");
  BMO_op_exec(bm, &weldop);

  BMO_op_finish(bm, &findop);
  BMO_op_finish(bm, &weldop);

  if ((totvert_prev != bm->totvert) && update) {
    EDBM_update(obedit->data,
                &(const struct EDBMUpdate_Params){
                    .calc_looptri = true,
                    .calc_normals = false,
                    .is_destructive = true,
                });
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Auto-Merge & Split Selection
 *
 * Used after transform operations.
 * \{ */

void EDBM_automerge_and_split(Object *obedit,
                              const bool UNUSED(split_edges),
                              const bool split_faces,
                              const bool update,
                              const char hflag,
                              const float dist)
{
  bool ok = false;

  BMEditMesh *em = BKE_editmesh_from_object(obedit);
  BMesh *bm = em->bm;

#ifdef DEBUG_TIME
  em->bm = BM_mesh_copy(bm);

  double t1 = PIL_check_seconds_timer();
  EDBM_automerge(obedit, false, hflag, dist);
  t1 = PIL_check_seconds_timer() - t1;

  BM_mesh_free(em->bm);
  em->bm = bm;
  double t2 = PIL_check_seconds_timer();
#endif

  BMOperator weldop;
  BMOpSlot *slot_targetmap;

  BMO_op_init(bm, &weldop, BMO_FLAG_DEFAULTS, "weld_verts");
  slot_targetmap = BMO_slot_get(weldop.slots_in, "targetmap");

  GHash *ghash_targetmap = BMO_SLOT_AS_GHASH(slot_targetmap);

  ok = BM_mesh_intersect_edges(bm, hflag, dist, split_faces, ghash_targetmap);

  if (ok) {
    BMO_op_exec(bm, &weldop);
  }

  BMO_op_finish(bm, &weldop);

#ifdef DEBUG_TIME
  t2 = PIL_check_seconds_timer() - t2;
  printf("t1: %lf; t2: %lf; fac: %lf\n", t1, t2, t1 / t2);
#endif

  if (LIKELY(ok) && update) {
    EDBM_update(obedit->data,
                &(const struct EDBMUpdate_Params){
                    .calc_looptri = true,
                    .calc_normals = false,
                    .is_destructive = true,
                });
  }
}

/** \} */