/*
 * 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) 2017, Blender Foundation
 * This is a new part of Blender
 */

/** \file
 * \ingroup modifiers
 */

#include <stdio.h>

#include "BLI_utildefines.h"

#include "BLI_math.h"

#include "DNA_meshdata_types.h"
#include "DNA_scene_types.h"
#include "DNA_object_types.h"
#include "DNA_gpencil_types.h"
#include "DNA_gpencil_modifier_types.h"

#include "BKE_colortools.h"
#include "BKE_deform.h"
#include "BKE_gpencil.h"
#include "BKE_gpencil_modifier.h"

#include "DEG_depsgraph.h"

#include "MOD_gpencil_util.h"
#include "MOD_gpencil_modifiertypes.h"

static void initData(GpencilModifierData *md)
{
  OffsetGpencilModifierData *gpmd = (OffsetGpencilModifierData *)md;
  gpmd->pass_index = 0;
  gpmd->layername[0] = '\0';
  gpmd->vgname[0] = '\0';
  ARRAY_SET_ITEMS(gpmd->loc, 0.0f, 0.0f, 0.0f);
  ARRAY_SET_ITEMS(gpmd->rot, 0.0f, 0.0f, 0.0f);
  ARRAY_SET_ITEMS(gpmd->scale, 0.0f, 0.0f, 0.0f);
}

static void copyData(const GpencilModifierData *md, GpencilModifierData *target)
{
  BKE_gpencil_modifier_copyData_generic(md, target);
}

/* change stroke offsetness */
static void deformStroke(GpencilModifierData *md,
                         Depsgraph *UNUSED(depsgraph),
                         Object *ob,
                         bGPDlayer *gpl,
                         bGPDstroke *gps)
{
  OffsetGpencilModifierData *mmd = (OffsetGpencilModifierData *)md;
  const int def_nr = defgroup_name_index(ob, mmd->vgname);

  float mat[4][4];
  float loc[3], rot[3], scale[3];

  if (!is_stroke_affected_by_modifier(ob,
                                      mmd->layername,
                                      mmd->pass_index,
                                      mmd->layer_pass,
                                      1,
                                      gpl,
                                      gps,
                                      mmd->flag & GP_OFFSET_INVERT_LAYER,
                                      mmd->flag & GP_OFFSET_INVERT_PASS,
                                      mmd->flag & GP_OFFSET_INVERT_LAYERPASS)) {
    return;
  }

  for (int i = 0; i < gps->totpoints; i++) {
    bGPDspoint *pt = &gps->points[i];
    MDeformVert *dvert = gps->dvert != NULL ? &gps->dvert[i] : NULL;

    /* verify vertex group */
    const float weight = get_modifier_point_weight(
        dvert, (mmd->flag & GP_OFFSET_INVERT_VGROUP) != 0, def_nr);
    if (weight < 0.0f) {
      continue;
    }
    /* calculate matrix */
    mul_v3_v3fl(loc, mmd->loc, weight);
    mul_v3_v3fl(rot, mmd->rot, weight);
    mul_v3_v3fl(scale, mmd->scale, weight);
    add_v3_fl(scale, 1.0);
    loc_eul_size_to_mat4(mat, loc, rot, scale);

    mul_m4_v3(mat, &pt->x);
  }
}

static void bakeModifier(struct Main *UNUSED(bmain),
                         Depsgraph *depsgraph,
                         GpencilModifierData *md,
                         Object *ob)
{
  bGPdata *gpd = ob->data;

  for (bGPDlayer *gpl = gpd->layers.first; gpl; gpl = gpl->next) {
    for (bGPDframe *gpf = gpl->frames.first; gpf; gpf = gpf->next) {
      for (bGPDstroke *gps = gpf->strokes.first; gps; gps = gps->next) {
        deformStroke(md, depsgraph, ob, gpl, gps);
      }
    }
  }
}

GpencilModifierTypeInfo modifierType_Gpencil_Offset = {
    /* name */ "Offset",
    /* structName */ "OffsetGpencilModifierData",
    /* structSize */ sizeof(OffsetGpencilModifierData),
    /* type */ eGpencilModifierTypeType_Gpencil,
    /* flags */ eGpencilModifierTypeFlag_SupportsEditmode,

    /* copyData */ copyData,

    /* deformStroke */ deformStroke,
    /* generateStrokes */ NULL,
    /* bakeModifier */ bakeModifier,
    /* remapTime */ NULL,

    /* initData */ initData,
    /* freeData */ NULL,
    /* isDisabled */ NULL,
    /* updateDepsgraph */ NULL,
    /* dependsOnTime */ NULL,
    /* foreachObjectLink */ NULL,
    /* foreachIDLink */ NULL,
    /* foreachTexLink */ NULL,
    /* getDuplicationFactor */ NULL,
};
