/*
 * 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) 2018, Blender Foundation
 * This is a new part of Blender
 */

/** \file
 * \ingroup modifiers
 */

#include <stdio.h>

#include "BLI_listbase.h"
#include "BLI_utildefines.h"

#include "BLI_math.h"

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

#include "BKE_armature.h"
#include "BKE_gpencil.h"
#include "BKE_gpencil_geom.h"
#include "BKE_gpencil_modifier.h"
#include "BKE_lib_query.h"
#include "BKE_main.h"
#include "BKE_modifier.h"
#include "BKE_scene.h"

#include "MEM_guardedalloc.h"

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

#include "DEG_depsgraph.h"
#include "DEG_depsgraph_build.h"
#include "DEG_depsgraph_query.h"

static void initData(GpencilModifierData *md)
{
  ArmatureGpencilModifierData *gpmd = (ArmatureGpencilModifierData *)md;
  gpmd->object = NULL;
  gpmd->deformflag = ARM_DEF_VGROUP;
}

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

static void gpencil_deform_verts(ArmatureGpencilModifierData *mmd, Object *target, bGPDstroke *gps)
{
  bGPDspoint *pt = gps->points;
  float(*vert_coords)[3] = MEM_mallocN(sizeof(float[3]) * gps->totpoints, __func__);
  int i;

  BKE_gpencil_dvert_ensure(gps);

  /* prepare array of points */
  for (i = 0; i < gps->totpoints; i++, pt++) {
    copy_v3_v3(vert_coords[i], &pt->x);
  }

  /* deform verts */
  BKE_armature_deform_coords_with_gpencil_stroke(mmd->object,
                                                 target,
                                                 vert_coords,
                                                 NULL,
                                                 gps->totpoints,
                                                 mmd->deformflag,
                                                 mmd->vert_coords_prev,
                                                 mmd->vgname,
                                                 gps);

  /* Apply deformed coordinates */
  pt = gps->points;
  for (i = 0; i < gps->totpoints; i++, pt++) {
    copy_v3_v3(&pt->x, vert_coords[i]);
  }

  MEM_freeN(vert_coords);
}

/* deform stroke */
static void deformStroke(GpencilModifierData *md,
                         Depsgraph *UNUSED(depsgraph),
                         Object *ob,
                         bGPDlayer *UNUSED(gpl),
                         bGPDframe *UNUSED(gpf),
                         bGPDstroke *gps)
{
  ArmatureGpencilModifierData *mmd = (ArmatureGpencilModifierData *)md;
  if (!mmd->object) {
    return;
  }

  gpencil_deform_verts(mmd, ob, gps);
  /* Calc geometry data. */
  BKE_gpencil_stroke_geometry_update(gps);
}

static void bakeModifier(Main *bmain, Depsgraph *depsgraph, GpencilModifierData *md, Object *ob)
{
  Scene *scene = DEG_get_evaluated_scene(depsgraph);
  Object *object_eval = DEG_get_evaluated_object(depsgraph, ob);
  ArmatureGpencilModifierData *mmd = (ArmatureGpencilModifierData *)md;
  GpencilModifierData *md_eval = BKE_gpencil_modifiers_findby_name(object_eval, md->name);
  bGPdata *gpd = (bGPdata *)ob->data;
  int oldframe = (int)DEG_get_ctime(depsgraph);

  if (mmd->object == NULL) {
    return;
  }

  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
    LISTBASE_FOREACH (bGPDframe *, gpf, &gpl->frames) {
      /* apply armature effects on this frame
       * NOTE: this assumes that we don't want armature animation on non-keyframed frames
       */
      CFRA = gpf->framenum;
      BKE_scene_graph_update_for_newframe(depsgraph, bmain);

      /* compute armature effects on this frame */
      LISTBASE_FOREACH (bGPDstroke *, gps, &gpf->strokes) {
        deformStroke(md_eval, depsgraph, object_eval, gpl, gpf, gps);
      }
    }
  }

  /* return frame state and DB to original state */
  CFRA = oldframe;
  BKE_scene_graph_update_for_newframe(depsgraph, bmain);
}

static bool isDisabled(GpencilModifierData *md, int UNUSED(userRenderParams))
{
  ArmatureGpencilModifierData *mmd = (ArmatureGpencilModifierData *)md;

  /* The object type check is only needed here in case we have a placeholder
   * object assigned (because the library containing the armature is missing).
   *
   * In other cases it should be impossible to have a type mismatch. */
  return !mmd->object || mmd->object->type != OB_ARMATURE;
}

static void updateDepsgraph(GpencilModifierData *md, const ModifierUpdateDepsgraphContext *ctx)
{
  ArmatureGpencilModifierData *lmd = (ArmatureGpencilModifierData *)md;
  if (lmd->object != NULL) {
    DEG_add_object_relation(ctx->node, lmd->object, DEG_OB_COMP_EVAL_POSE, "Armature Modifier");
    DEG_add_object_relation(ctx->node, lmd->object, DEG_OB_COMP_TRANSFORM, "Armature Modifier");
  }
  DEG_add_object_relation(ctx->node, ctx->object, DEG_OB_COMP_TRANSFORM, "Armature Modifier");
}

static void foreachObjectLink(GpencilModifierData *md,
                              Object *ob,
                              ObjectWalkFunc walk,
                              void *userData)
{
  ArmatureGpencilModifierData *mmd = (ArmatureGpencilModifierData *)md;

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

GpencilModifierTypeInfo modifierType_Gpencil_Armature = {
    /* name */ "Armature",
    /* structName */ "ArmatureGpencilModifierData",
    /* structSize */ sizeof(ArmatureGpencilModifierData),
    /* type */ eGpencilModifierTypeType_Gpencil,
    /* flags */ eGpencilModifierTypeFlag_SupportsEditmode,

    /* copyData */ copyData,

    /* deformStroke */ deformStroke,
    /* generateStrokes */ NULL,
    /* bakeModifier */ bakeModifier,
    /* remapTime */ NULL,
    /* initData */ initData,
    /* freeData */ NULL,
    /* isDisabled */ isDisabled,
    /* updateDepsgraph */ updateDepsgraph,
    /* dependsOnTime */ NULL,
    /* foreachObjectLink */ foreachObjectLink,
    /* foreachIDLink */ NULL,
    /* foreachTexLink */ NULL,
};