/*
 * 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_listbase.h"
#include "BLI_utildefines.h"

#include "BLI_ghash.h"
#include "BLI_hash.h"
#include "BLI_math_vector.h"
#include "BLI_rand.h"

#include "MEM_guardedalloc.h"

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

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

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

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

static void initData(GpencilModifierData *md)
{
  NoiseGpencilModifierData *gpmd = (NoiseGpencilModifierData *)md;
  gpmd->pass_index = 0;
  gpmd->flag |= GP_NOISE_FULL_STROKE;
  gpmd->flag |= GP_NOISE_USE_RANDOM;
  gpmd->factor = 0.5f;
  gpmd->layername[0] = '\0';
  gpmd->materialname[0] = '\0';
  gpmd->vgname[0] = '\0';
  gpmd->step = 4;
  gpmd->seed = 1;
  gpmd->curve_intensity = BKE_curvemapping_add(1, 0.0f, 0.0f, 1.0f, 1.0f);
  if (gpmd->curve_intensity) {
    CurveMapping *curve = gpmd->curve_intensity;
    BKE_curvemap_reset(curve->cm, &curve->clipr, CURVE_PRESET_BELL, CURVEMAP_SLOPE_POSITIVE);
    BKE_curvemapping_initialize(curve);
  }
}

static void freeData(GpencilModifierData *md)
{
  NoiseGpencilModifierData *gpmd = (NoiseGpencilModifierData *)md;

  if (gpmd->curve_intensity) {
    BKE_curvemapping_free(gpmd->curve_intensity);
  }
}

static void copyData(const GpencilModifierData *md, GpencilModifierData *target)
{
  NoiseGpencilModifierData *gmd = (NoiseGpencilModifierData *)md;
  NoiseGpencilModifierData *tgmd = (NoiseGpencilModifierData *)target;

  if (tgmd->curve_intensity != NULL) {
    BKE_curvemapping_free(tgmd->curve_intensity);
    tgmd->curve_intensity = NULL;
  }

  BKE_gpencil_modifier_copyData_generic(md, target);

  tgmd->curve_intensity = BKE_curvemapping_copy(gmd->curve_intensity);
}

static bool dependsOnTime(GpencilModifierData *md)
{
  NoiseGpencilModifierData *mmd = (NoiseGpencilModifierData *)md;
  return (mmd->flag & GP_NOISE_USE_RANDOM) != 0;
}

static float *noise_table(int len, int seed)
{
  float *table = MEM_callocN(sizeof(float) * len, __func__);
  for (int i = 0; i < len; i++) {
    table[i] = BLI_hash_int_01(BLI_hash_int_2d(seed, i + 1));
  }
  return table;
}

BLI_INLINE float table_sample(float *table, float x)
{
  return interpf(table[(int)ceilf(x)], table[(int)floor(x)], fractf(x));
}

/* aply noise effect based on stroke direction */
static void deformStroke(GpencilModifierData *md,
                         Depsgraph *depsgraph,
                         Object *ob,
                         bGPDlayer *gpl,
                         bGPDframe *gpf,
                         bGPDstroke *gps)
{
  NoiseGpencilModifierData *mmd = (NoiseGpencilModifierData *)md;
  MDeformVert *dvert = NULL;
  /* Noise value in range [-1..1] */
  float normal[3];
  float vec1[3], vec2[3];
  const int def_nr = BKE_object_defgroup_name_index(ob, mmd->vgname);
  const bool invert_group = (mmd->flag & GP_NOISE_INVERT_VGROUP) != 0;
  const bool use_curve = (mmd->flag & GP_NOISE_CUSTOM_CURVE) != 0 && mmd->curve_intensity;

  if (!is_stroke_affected_by_modifier(ob,
                                      mmd->layername,
                                      mmd->materialname,
                                      mmd->pass_index,
                                      mmd->layer_pass,
                                      1,
                                      gpl,
                                      gps,
                                      mmd->flag & GP_NOISE_INVERT_LAYER,
                                      mmd->flag & GP_NOISE_INVERT_PASS,
                                      mmd->flag & GP_NOISE_INVERT_LAYERPASS,
                                      mmd->flag & GP_NOISE_INVERT_MATERIAL)) {
    return;
  }

  int seed = mmd->seed;
  /* FIXME(fclem): This is really slow. We should get the stroke index in another way. */
  int stroke_seed = BLI_findindex(&gpf->strokes, gps);
  seed += stroke_seed;

  /* Make sure different modifiers get different seeds. */
  seed += BLI_hash_string(ob->id.name + 2);
  seed += BLI_hash_string(md->name);

  if (mmd->flag & GP_NOISE_USE_RANDOM) {
    seed += ((int)DEG_get_ctime(depsgraph)) / mmd->step;
  }

  /* Sanitize as it can create out of bound reads. */
  float noise_scale = clamp_f(mmd->noise_scale, 0.0f, 1.0f);

  int len = ceilf(gps->totpoints * noise_scale) + 1;
  float *noise_table_position = (mmd->factor > 0.0f) ? noise_table(len, seed + 2) : NULL;
  float *noise_table_strength = (mmd->factor_strength > 0.0f) ? noise_table(len, seed + 3) : NULL;
  float *noise_table_thickness = (mmd->factor_thickness > 0.0f) ? noise_table(len, seed) : NULL;
  float *noise_table_uvs = (mmd->factor_uvs > 0.0f) ? noise_table(len, seed + 4) : NULL;

  /* Calculate stroke normal. */
  if (gps->totpoints > 2) {
    BKE_gpencil_stroke_normal(gps, normal);
    if (is_zero_v3(normal)) {
      copy_v3_fl(normal, 1.0f);
    }
  }
  else {
    copy_v3_fl(normal, 1.0f);
  }

  /* move points */
  for (int i = 0; i < gps->totpoints; i++) {
    bGPDspoint *pt = &gps->points[i];
    /* verify vertex group */
    dvert = gps->dvert != NULL ? &gps->dvert[i] : NULL;
    float weight = get_modifier_point_weight(dvert, invert_group, def_nr);
    if (weight < 0.0f) {
      continue;
    }

    if (use_curve) {
      float value = (float)i / (gps->totpoints - 1);
      weight *= BKE_curvemapping_evaluateF(mmd->curve_intensity, 0, value);
    }

    if (mmd->factor > 0.0f) {
      /* Offset point randomly around the bi-normal vector. */
      if (gps->totpoints == 1) {
        copy_v3_fl3(vec1, 1.0f, 0.0f, 0.0f);
      }
      else if (i != gps->totpoints - 1) {
        /* Initial vector (p1 -> p0). */
        sub_v3_v3v3(vec1, &gps->points[i].x, &gps->points[i + 1].x);
        /* if vec2 is zero, set to something */
        if (len_squared_v3(vec1) < 1e-8f) {
          copy_v3_fl3(vec1, 1.0f, 0.0f, 0.0f);
        }
      }
      else {
        /* Last point reuse the penultimate normal (still stored in vec1)
         * because the previous point is already modified. */
      }
      /* Vector orthogonal to normal. */
      cross_v3_v3v3(vec2, vec1, normal);
      normalize_v3(vec2);

      float noise = table_sample(noise_table_position, i * noise_scale);
      madd_v3_v3fl(&pt->x, vec2, (noise * 2.0f - 1.0f) * weight * mmd->factor * 0.1f);
    }

    if (mmd->factor_thickness > 0.0f) {
      float noise = table_sample(noise_table_thickness, i * noise_scale);
      pt->pressure *= max_ff(1.0f + (noise * 2.0f - 1.0f) * weight * mmd->factor_thickness, 0.0f);
      CLAMP_MIN(pt->pressure, GPENCIL_STRENGTH_MIN);
    }

    if (mmd->factor_strength > 0.0f) {
      float noise = table_sample(noise_table_strength, i * noise_scale);
      pt->strength *= max_ff(1.0f - noise * weight * mmd->factor_strength, 0.0f);
      CLAMP(pt->strength, GPENCIL_STRENGTH_MIN, 1.0f);
    }

    if (mmd->factor_uvs > 0.0f) {
      float noise = table_sample(noise_table_uvs, i * noise_scale);
      pt->uv_rot += (noise * 2.0f - 1.0f) * weight * mmd->factor_uvs * M_PI_2;
      CLAMP(pt->uv_rot, -M_PI_2, M_PI_2);
    }
  }

  MEM_SAFE_FREE(noise_table_position);
  MEM_SAFE_FREE(noise_table_strength);
  MEM_SAFE_FREE(noise_table_thickness);
  MEM_SAFE_FREE(noise_table_uvs);
}

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

  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
    LISTBASE_FOREACH (bGPDframe *, gpf, &gpl->frames) {
      LISTBASE_FOREACH (bGPDstroke *, gps, &gpf->strokes) {
        deformStroke(md, depsgraph, ob, gpl, gpf, gps);
      }
    }
  }
}

GpencilModifierTypeInfo modifierType_Gpencil_Noise = {
    /* name */ "Noise",
    /* structName */ "NoiseGpencilModifierData",
    /* structSize */ sizeof(NoiseGpencilModifierData),
    /* type */ eGpencilModifierTypeType_Gpencil,
    /* flags */ eGpencilModifierTypeFlag_SupportsEditmode,

    /* copyData */ copyData,

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

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