/*
 * 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) 2005 by the Blender Foundation.
 * All rights reserved.
 */

/** \file
 * \ingroup modifiers
 */

#include "BLI_utildefines.h"

#include "BLI_math.h"

#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_object_types.h"

#include "BKE_deform.h"
#include "BKE_editmesh.h"
#include "BKE_lib_id.h"
#include "BKE_lib_query.h"
#include "BKE_mesh.h"
#include "BKE_modifier.h"

#include "DEG_depsgraph_query.h"

#include "MOD_util.h"

static void initData(ModifierData *md)
{
  CastModifierData *cmd = (CastModifierData *)md;

  cmd->fac = 0.5f;
  cmd->radius = 0.0f;
  cmd->size = 0.0f;
  cmd->flag = MOD_CAST_X | MOD_CAST_Y | MOD_CAST_Z | MOD_CAST_SIZE_FROM_RADIUS;
  cmd->type = MOD_CAST_TYPE_SPHERE;
  cmd->defgrp_name[0] = '\0';
  cmd->object = NULL;
}

static bool isDisabled(const struct Scene *UNUSED(scene),
                       ModifierData *md,
                       bool UNUSED(useRenderParams))
{
  CastModifierData *cmd = (CastModifierData *)md;
  short flag;

  flag = cmd->flag & (MOD_CAST_X | MOD_CAST_Y | MOD_CAST_Z);

  if ((cmd->fac == 0.0f) || flag == 0) {
    return true;
  }

  return false;
}

static void requiredDataMask(Object *UNUSED(ob),
                             ModifierData *md,
                             CustomData_MeshMasks *r_cddata_masks)
{
  CastModifierData *cmd = (CastModifierData *)md;

  /* ask for vertexgroups if we need them */
  if (cmd->defgrp_name[0] != '\0') {
    r_cddata_masks->vmask |= CD_MASK_MDEFORMVERT;
  }
}

static void foreachObjectLink(ModifierData *md, Object *ob, ObjectWalkFunc walk, void *userData)
{
  CastModifierData *cmd = (CastModifierData *)md;

  walk(userData, ob, &cmd->object, IDWALK_CB_NOP);
}

static void updateDepsgraph(ModifierData *md, const ModifierUpdateDepsgraphContext *ctx)
{
  CastModifierData *cmd = (CastModifierData *)md;
  if (cmd->object != NULL) {
    DEG_add_object_relation(ctx->node, cmd->object, DEG_OB_COMP_TRANSFORM, "Cast Modifier");
    DEG_add_modifier_to_transform_relation(ctx->node, "Cast Modifier");
  }
}

static void sphere_do(CastModifierData *cmd,
                      const ModifierEvalContext *UNUSED(ctx),
                      Object *ob,
                      Mesh *mesh,
                      float (*vertexCos)[3],
                      int numVerts)
{
  MDeformVert *dvert = NULL;
  const bool invert_vgroup = (cmd->flag & MOD_CAST_INVERT_VGROUP) != 0;

  Object *ctrl_ob = NULL;

  int i, defgrp_index;
  bool has_radius = false;
  short flag, type;
  float len = 0.0f;
  float fac = cmd->fac;
  float facm = 1.0f - fac;
  const float fac_orig = fac;
  float vec[3], center[3] = {0.0f, 0.0f, 0.0f};
  float mat[4][4], imat[4][4];

  flag = cmd->flag;
  type = cmd->type; /* projection type: sphere or cylinder */

  if (type == MOD_CAST_TYPE_CYLINDER) {
    flag &= ~MOD_CAST_Z;
  }

  ctrl_ob = cmd->object;

  /* spherify's center is {0, 0, 0} (the ob's own center in its local
   * space), by default, but if the user defined a control object,
   * we use its location, transformed to ob's local space */
  if (ctrl_ob) {
    if (flag & MOD_CAST_USE_OB_TRANSFORM) {
      invert_m4_m4(imat, ctrl_ob->obmat);
      mul_m4_m4m4(mat, imat, ob->obmat);
      invert_m4_m4(imat, mat);
    }

    invert_m4_m4(ob->imat, ob->obmat);
    mul_v3_m4v3(center, ob->imat, ctrl_ob->obmat[3]);
  }

  /* now we check which options the user wants */

  /* 1) (flag was checked in the "if (ctrl_ob)" block above) */
  /* 2) cmd->radius > 0.0f: only the vertices within this radius from
   * the center of the effect should be deformed */
  if (cmd->radius > FLT_EPSILON) {
    has_radius = 1;
  }

  /* 3) if we were given a vertex group name,
   * only those vertices should be affected */
  if (cmd->defgrp_name[0] != '\0') {
    MOD_get_vgroup(ob, mesh, cmd->defgrp_name, &dvert, &defgrp_index);
  }

  if (flag & MOD_CAST_SIZE_FROM_RADIUS) {
    len = cmd->radius;
  }
  else {
    len = cmd->size;
  }

  if (len <= 0) {
    for (i = 0; i < numVerts; i++) {
      len += len_v3v3(center, vertexCos[i]);
    }
    len /= numVerts;

    if (len == 0.0f) {
      len = 10.0f;
    }
  }

  for (i = 0; i < numVerts; i++) {
    float tmp_co[3];

    copy_v3_v3(tmp_co, vertexCos[i]);
    if (ctrl_ob) {
      if (flag & MOD_CAST_USE_OB_TRANSFORM) {
        mul_m4_v3(mat, tmp_co);
      }
      else {
        sub_v3_v3(tmp_co, center);
      }
    }

    copy_v3_v3(vec, tmp_co);

    if (type == MOD_CAST_TYPE_CYLINDER) {
      vec[2] = 0.0f;
    }

    if (has_radius) {
      if (len_v3(vec) > cmd->radius) {
        continue;
      }
    }

    if (dvert) {
      const float weight = invert_vgroup ?
                               1.0f - BKE_defvert_find_weight(&dvert[i], defgrp_index) :
                               BKE_defvert_find_weight(&dvert[i], defgrp_index);

      if (weight == 0.0f) {
        continue;
      }

      fac = fac_orig * weight;
      facm = 1.0f - fac;
    }

    normalize_v3(vec);

    if (flag & MOD_CAST_X) {
      tmp_co[0] = fac * vec[0] * len + facm * tmp_co[0];
    }
    if (flag & MOD_CAST_Y) {
      tmp_co[1] = fac * vec[1] * len + facm * tmp_co[1];
    }
    if (flag & MOD_CAST_Z) {
      tmp_co[2] = fac * vec[2] * len + facm * tmp_co[2];
    }

    if (ctrl_ob) {
      if (flag & MOD_CAST_USE_OB_TRANSFORM) {
        mul_m4_v3(imat, tmp_co);
      }
      else {
        add_v3_v3(tmp_co, center);
      }
    }

    copy_v3_v3(vertexCos[i], tmp_co);
  }
}

static void cuboid_do(CastModifierData *cmd,
                      const ModifierEvalContext *UNUSED(ctx),
                      Object *ob,
                      Mesh *mesh,
                      float (*vertexCos)[3],
                      int numVerts)
{
  MDeformVert *dvert = NULL;
  int defgrp_index;
  const bool invert_vgroup = (cmd->flag & MOD_CAST_INVERT_VGROUP) != 0;

  Object *ctrl_ob = NULL;

  int i;
  bool has_radius = false;
  short flag;
  float fac = cmd->fac;
  float facm = 1.0f - fac;
  const float fac_orig = fac;
  float min[3], max[3], bb[8][3];
  float center[3] = {0.0f, 0.0f, 0.0f};
  float mat[4][4], imat[4][4];

  flag = cmd->flag;

  ctrl_ob = cmd->object;

  /* now we check which options the user wants */

  /* 1) (flag was checked in the "if (ctrl_ob)" block above) */
  /* 2) cmd->radius > 0.0f: only the vertices within this radius from
   * the center of the effect should be deformed */
  if (cmd->radius > FLT_EPSILON) {
    has_radius = 1;
  }

  /* 3) if we were given a vertex group name,
   * only those vertices should be affected */
  if (cmd->defgrp_name[0] != '\0') {
    MOD_get_vgroup(ob, mesh, cmd->defgrp_name, &dvert, &defgrp_index);
  }

  if (ctrl_ob) {
    if (flag & MOD_CAST_USE_OB_TRANSFORM) {
      invert_m4_m4(imat, ctrl_ob->obmat);
      mul_m4_m4m4(mat, imat, ob->obmat);
      invert_m4_m4(imat, mat);
    }

    invert_m4_m4(ob->imat, ob->obmat);
    mul_v3_m4v3(center, ob->imat, ctrl_ob->obmat[3]);
  }

  if ((flag & MOD_CAST_SIZE_FROM_RADIUS) && has_radius) {
    for (i = 0; i < 3; i++) {
      min[i] = -cmd->radius;
      max[i] = cmd->radius;
    }
  }
  else if (!(flag & MOD_CAST_SIZE_FROM_RADIUS) && cmd->size > 0) {
    for (i = 0; i < 3; i++) {
      min[i] = -cmd->size;
      max[i] = cmd->size;
    }
  }
  else {
    /* get bound box */
    /* We can't use the object's bound box because other modifiers
     * may have changed the vertex data. */
    INIT_MINMAX(min, max);

    /* Cast's center is the ob's own center in its local space,
     * by default, but if the user defined a control object, we use
     * its location, transformed to ob's local space. */
    if (ctrl_ob) {
      float vec[3];

      /* let the center of the ctrl_ob be part of the bound box: */
      minmax_v3v3_v3(min, max, center);

      for (i = 0; i < numVerts; i++) {
        sub_v3_v3v3(vec, vertexCos[i], center);
        minmax_v3v3_v3(min, max, vec);
      }
    }
    else {
      for (i = 0; i < numVerts; i++) {
        minmax_v3v3_v3(min, max, vertexCos[i]);
      }
    }

    /* we want a symmetric bound box around the origin */
    if (fabsf(min[0]) > fabsf(max[0])) {
      max[0] = fabsf(min[0]);
    }
    if (fabsf(min[1]) > fabsf(max[1])) {
      max[1] = fabsf(min[1]);
    }
    if (fabsf(min[2]) > fabsf(max[2])) {
      max[2] = fabsf(min[2]);
    }
    min[0] = -max[0];
    min[1] = -max[1];
    min[2] = -max[2];
  }

  /* building our custom bounding box */
  bb[0][0] = bb[2][0] = bb[4][0] = bb[6][0] = min[0];
  bb[1][0] = bb[3][0] = bb[5][0] = bb[7][0] = max[0];
  bb[0][1] = bb[1][1] = bb[4][1] = bb[5][1] = min[1];
  bb[2][1] = bb[3][1] = bb[6][1] = bb[7][1] = max[1];
  bb[0][2] = bb[1][2] = bb[2][2] = bb[3][2] = min[2];
  bb[4][2] = bb[5][2] = bb[6][2] = bb[7][2] = max[2];

  /* ready to apply the effect, one vertex at a time */
  for (i = 0; i < numVerts; i++) {
    int octant, coord;
    float d[3], dmax, apex[3], fbb;
    float tmp_co[3];

    copy_v3_v3(tmp_co, vertexCos[i]);
    if (ctrl_ob) {
      if (flag & MOD_CAST_USE_OB_TRANSFORM) {
        mul_m4_v3(mat, tmp_co);
      }
      else {
        sub_v3_v3(tmp_co, center);
      }
    }

    if (has_radius) {
      if (fabsf(tmp_co[0]) > cmd->radius || fabsf(tmp_co[1]) > cmd->radius ||
          fabsf(tmp_co[2]) > cmd->radius) {
        continue;
      }
    }

    if (dvert) {
      const float weight = invert_vgroup ?
                               1.0f - BKE_defvert_find_weight(&dvert[i], defgrp_index) :
                               BKE_defvert_find_weight(&dvert[i], defgrp_index);

      if (weight == 0.0f) {
        continue;
      }

      fac = fac_orig * weight;
      facm = 1.0f - fac;
    }

    /* The algo used to project the vertices to their
     * bounding box (bb) is pretty simple:
     * for each vertex v:
     * 1) find in which octant v is in;
     * 2) find which outer "wall" of that octant is closer to v;
     * 3) calculate factor (var fbb) to project v to that wall;
     * 4) project. */

    /* find in which octant this vertex is in */
    octant = 0;
    if (tmp_co[0] > 0.0f) {
      octant += 1;
    }
    if (tmp_co[1] > 0.0f) {
      octant += 2;
    }
    if (tmp_co[2] > 0.0f) {
      octant += 4;
    }

    /* apex is the bb's vertex at the chosen octant */
    copy_v3_v3(apex, bb[octant]);

    /* find which bb plane is closest to this vertex ... */
    d[0] = tmp_co[0] / apex[0];
    d[1] = tmp_co[1] / apex[1];
    d[2] = tmp_co[2] / apex[2];

    /* ... (the closest has the higher (closer to 1) d value) */
    dmax = d[0];
    coord = 0;
    if (d[1] > dmax) {
      dmax = d[1];
      coord = 1;
    }
    if (d[2] > dmax) {
      /* dmax = d[2]; */ /* commented, we don't need it */
      coord = 2;
    }

    /* ok, now we know which coordinate of the vertex to use */

    if (fabsf(tmp_co[coord]) < FLT_EPSILON) { /* avoid division by zero */
      continue;
    }

    /* finally, this is the factor we wanted, to project the vertex
     * to its bounding box (bb) */
    fbb = apex[coord] / tmp_co[coord];

    /* calculate the new vertex position */
    if (flag & MOD_CAST_X) {
      tmp_co[0] = facm * tmp_co[0] + fac * tmp_co[0] * fbb;
    }
    if (flag & MOD_CAST_Y) {
      tmp_co[1] = facm * tmp_co[1] + fac * tmp_co[1] * fbb;
    }
    if (flag & MOD_CAST_Z) {
      tmp_co[2] = facm * tmp_co[2] + fac * tmp_co[2] * fbb;
    }

    if (ctrl_ob) {
      if (flag & MOD_CAST_USE_OB_TRANSFORM) {
        mul_m4_v3(imat, tmp_co);
      }
      else {
        add_v3_v3(tmp_co, center);
      }
    }

    copy_v3_v3(vertexCos[i], tmp_co);
  }
}

static void deformVerts(ModifierData *md,
                        const ModifierEvalContext *ctx,
                        Mesh *mesh,
                        float (*vertexCos)[3],
                        int numVerts)
{
  CastModifierData *cmd = (CastModifierData *)md;
  Mesh *mesh_src = NULL;

  if (ctx->object->type == OB_MESH && cmd->defgrp_name[0] != '\0') {
    /* mesh_src is only needed for vgroups. */
    mesh_src = MOD_deform_mesh_eval_get(ctx->object, NULL, mesh, NULL, numVerts, false, false);
  }

  if (cmd->type == MOD_CAST_TYPE_CUBOID) {
    cuboid_do(cmd, ctx, ctx->object, mesh_src, vertexCos, numVerts);
  }
  else { /* MOD_CAST_TYPE_SPHERE or MOD_CAST_TYPE_CYLINDER */
    sphere_do(cmd, ctx, ctx->object, mesh_src, vertexCos, numVerts);
  }

  if (!ELEM(mesh_src, NULL, mesh)) {
    BKE_id_free(NULL, mesh_src);
  }
}

static void deformVertsEM(ModifierData *md,
                          const ModifierEvalContext *ctx,
                          struct BMEditMesh *editData,
                          Mesh *mesh,
                          float (*vertexCos)[3],
                          int numVerts)
{
  CastModifierData *cmd = (CastModifierData *)md;
  Mesh *mesh_src = NULL;

  if (cmd->defgrp_name[0] != '\0') {
    mesh_src = MOD_deform_mesh_eval_get(ctx->object, editData, mesh, NULL, numVerts, false, false);
  }

  if (mesh_src) {
    BLI_assert(mesh_src->totvert == numVerts);
  }

  if (cmd->type == MOD_CAST_TYPE_CUBOID) {
    cuboid_do(cmd, ctx, ctx->object, mesh_src, vertexCos, numVerts);
  }
  else { /* MOD_CAST_TYPE_SPHERE or MOD_CAST_TYPE_CYLINDER */
    sphere_do(cmd, ctx, ctx->object, mesh_src, vertexCos, numVerts);
  }

  if (!ELEM(mesh_src, NULL, mesh)) {
    BKE_id_free(NULL, mesh_src);
  }
}

ModifierTypeInfo modifierType_Cast = {
    /* name */ "Cast",
    /* structName */ "CastModifierData",
    /* structSize */ sizeof(CastModifierData),
    /* type */ eModifierTypeType_OnlyDeform,
    /* flags */ eModifierTypeFlag_AcceptsCVs | eModifierTypeFlag_AcceptsLattice |
        eModifierTypeFlag_SupportsEditmode,

    /* copyData */ modifier_copyData_generic,

    /* deformVerts */ deformVerts,
    /* deformMatrices */ NULL,
    /* deformVertsEM */ deformVertsEM,
    /* deformMatricesEM */ NULL,
    /* applyModifier */ NULL,

    /* initData */ initData,
    /* requiredDataMask */ requiredDataMask,
    /* freeData */ NULL,
    /* isDisabled */ isDisabled,
    /* updateDepsgraph */ updateDepsgraph,
    /* dependsOnTime */ NULL,
    /* dependsOnNormals */ NULL,
    /* foreachObjectLink */ foreachObjectLink,
    /* foreachIDLink */ NULL,
    /* foreachTexLink */ NULL,
    /* freeRuntimeData */ NULL,
};
