/* SPDX-License-Identifier: GPL-2.0-or-later
 * Copyright 2020 Blender Foundation. All rights reserved. */

/** \file
 * \ingroup edsculpt
 */

#include "MEM_guardedalloc.h"

#include "BLI_math.h"
#include "BLI_task.h"

#include "DNA_meshdata_types.h"

#include "BKE_brush.h"
#include "BKE_context.h"
#include "BKE_kelvinlet.h"
#include "BKE_paint.h"
#include "BKE_pbvh.h"

#include "DEG_depsgraph.h"

#include "WM_api.h"
#include "WM_types.h"

#include "ED_screen.h"
#include "ED_sculpt.h"
#include "ED_view3d.h"
#include "paint_intern.h"
#include "sculpt_intern.h"

#include "RNA_access.h"
#include "RNA_define.h"

#include "bmesh.h"

#include <math.h>
#include <stdlib.h>

void ED_sculpt_init_transform(struct bContext *C,
                              Object *ob,
                              const int mval[2],
                              const char *undo_name)
{
  Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
  SculptSession *ss = ob->sculpt;
  Depsgraph *depsgraph = CTX_data_depsgraph_pointer(C);

  copy_v3_v3(ss->init_pivot_pos, ss->pivot_pos);
  copy_v4_v4(ss->init_pivot_rot, ss->pivot_rot);
  copy_v3_v3(ss->init_pivot_scale, ss->pivot_scale);

  copy_v3_v3(ss->prev_pivot_pos, ss->pivot_pos);
  copy_v4_v4(ss->prev_pivot_rot, ss->pivot_rot);
  copy_v3_v3(ss->prev_pivot_scale, ss->pivot_scale);

  SCULPT_undo_push_begin_ex(ob, undo_name);
  BKE_sculpt_update_object_for_edit(depsgraph, ob, false, false, false);

  ss->pivot_rot[3] = 1.0f;

  SCULPT_vertex_random_access_ensure(ss);

  SCULPT_filter_cache_init(C, ob, sd, SCULPT_UNDO_COORDS, mval, 5.0);

  if (sd->transform_mode == SCULPT_TRANSFORM_MODE_RADIUS_ELASTIC) {
    ss->filter_cache->transform_displacement_mode = SCULPT_TRANSFORM_DISPLACEMENT_INCREMENTAL;
  }
  else {
    ss->filter_cache->transform_displacement_mode = SCULPT_TRANSFORM_DISPLACEMENT_ORIGINAL;
  }
}

static void sculpt_transform_matrices_init(SculptSession *ss,
                                           const char symm,
                                           const SculptTransformDisplacementMode t_mode,
                                           float r_transform_mats[8][4][4])
{

  float final_pivot_pos[3], d_t[3], d_r[4], d_s[3];
  float t_mat[4][4], r_mat[4][4], s_mat[4][4], pivot_mat[4][4], pivot_imat[4][4],
      transform_mat[4][4];

  float start_pivot_pos[3], start_pivot_rot[4], start_pivot_scale[3];
  switch (t_mode) {
    case SCULPT_TRANSFORM_DISPLACEMENT_ORIGINAL:
      copy_v3_v3(start_pivot_pos, ss->init_pivot_pos);
      copy_v4_v4(start_pivot_rot, ss->init_pivot_rot);
      copy_v3_v3(start_pivot_scale, ss->init_pivot_scale);
      break;
    case SCULPT_TRANSFORM_DISPLACEMENT_INCREMENTAL:
      copy_v3_v3(start_pivot_pos, ss->prev_pivot_pos);
      copy_v4_v4(start_pivot_rot, ss->prev_pivot_rot);
      copy_v3_v3(start_pivot_scale, ss->prev_pivot_scale);
      break;
  }

  for (int i = 0; i < PAINT_SYMM_AREAS; i++) {
    ePaintSymmetryAreas v_symm = i;

    copy_v3_v3(final_pivot_pos, ss->pivot_pos);

    unit_m4(pivot_mat);

    unit_m4(t_mat);
    unit_m4(r_mat);
    unit_m4(s_mat);

    /* Translation matrix. */
    sub_v3_v3v3(d_t, ss->pivot_pos, start_pivot_pos);
    SCULPT_flip_v3_by_symm_area(d_t, symm, v_symm, ss->init_pivot_pos);
    translate_m4(t_mat, d_t[0], d_t[1], d_t[2]);

    /* Rotation matrix. */
    sub_qt_qtqt(d_r, ss->pivot_rot, start_pivot_rot);
    normalize_qt(d_r);
    SCULPT_flip_quat_by_symm_area(d_r, symm, v_symm, ss->init_pivot_pos);
    quat_to_mat4(r_mat, d_r);

    /* Scale matrix. */
    sub_v3_v3v3(d_s, ss->pivot_scale, start_pivot_scale);
    add_v3_fl(d_s, 1.0f);
    size_to_mat4(s_mat, d_s);

    /* Pivot matrix. */
    SCULPT_flip_v3_by_symm_area(final_pivot_pos, symm, v_symm, start_pivot_pos);
    translate_m4(pivot_mat, final_pivot_pos[0], final_pivot_pos[1], final_pivot_pos[2]);
    invert_m4_m4(pivot_imat, pivot_mat);

    /* Final transform matrix. */
    mul_m4_m4m4(transform_mat, r_mat, t_mat);
    mul_m4_m4m4(transform_mat, transform_mat, s_mat);
    mul_m4_m4m4(r_transform_mats[i], transform_mat, pivot_imat);
    mul_m4_m4m4(r_transform_mats[i], pivot_mat, r_transform_mats[i]);
  }
}

static void sculpt_transform_task_cb(void *__restrict userdata,
                                     const int i,
                                     const TaskParallelTLS *__restrict UNUSED(tls))
{

  SculptThreadedTaskData *data = userdata;
  SculptSession *ss = data->ob->sculpt;
  PBVHNode *node = data->nodes[i];

  SculptOrigVertData orig_data;
  SCULPT_orig_vert_data_init(&orig_data, data->ob, data->nodes[i], SCULPT_UNDO_COORDS);

  PBVHVertexIter vd;

  SCULPT_undo_push_node(data->ob, node, SCULPT_UNDO_COORDS);
  BKE_pbvh_vertex_iter_begin (ss->pbvh, node, vd, PBVH_ITER_UNIQUE) {
    SCULPT_orig_vert_data_update(&orig_data, &vd);
    float *start_co;
    float transformed_co[3], orig_co[3], disp[3];
    float fade = vd.mask ? *vd.mask : 0.0f;
    copy_v3_v3(orig_co, orig_data.co);
    char symm_area = SCULPT_get_vertex_symm_area(orig_co);

    switch (ss->filter_cache->transform_displacement_mode) {
      case SCULPT_TRANSFORM_DISPLACEMENT_ORIGINAL:
        start_co = orig_co;
        break;
      case SCULPT_TRANSFORM_DISPLACEMENT_INCREMENTAL:
        start_co = vd.co;
        break;
    }

    copy_v3_v3(transformed_co, start_co);
    mul_m4_v3(data->transform_mats[(int)symm_area], transformed_co);
    sub_v3_v3v3(disp, transformed_co, start_co);
    mul_v3_fl(disp, 1.0f - fade);
    add_v3_v3v3(vd.co, start_co, disp);

    if (vd.mvert) {
      BKE_pbvh_vert_tag_update_normal(ss->pbvh, vd.vertex);
    }
  }
  BKE_pbvh_vertex_iter_end;

  BKE_pbvh_node_mark_update(node);
}

static void sculpt_transform_all_vertices(Sculpt *sd, Object *ob)
{
  SculptSession *ss = ob->sculpt;
  const char symm = SCULPT_mesh_symmetry_xyz_get(ob);

  SculptThreadedTaskData data = {
      .sd = sd,
      .ob = ob,
      .nodes = ss->filter_cache->nodes,
  };

  sculpt_transform_matrices_init(
      ss, symm, ss->filter_cache->transform_displacement_mode, data.transform_mats);

  /* Regular transform applies all symmetry passes at once as it is split by symmetry areas
   * (each vertex can only be transformed once by the transform matrix of its area). */
  TaskParallelSettings settings;
  BKE_pbvh_parallel_range_settings(&settings, true, ss->filter_cache->totnode);
  BLI_task_parallel_range(
      0, ss->filter_cache->totnode, &data, sculpt_transform_task_cb, &settings);
}

static void sculpt_elastic_transform_task_cb(void *__restrict userdata,
                                             const int i,
                                             const TaskParallelTLS *__restrict UNUSED(tls))
{

  SculptThreadedTaskData *data = userdata;
  SculptSession *ss = data->ob->sculpt;
  PBVHNode *node = data->nodes[i];

  float(*proxy)[3] = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[i])->co;

  SculptOrigVertData orig_data;
  SCULPT_orig_vert_data_init(&orig_data, data->ob, data->nodes[i], SCULPT_UNDO_COORDS);

  KelvinletParams params;
  /* TODO(pablodp606): These parameters can be exposed if needed as transform strength and volume
   * preservation like in the elastic deform brushes. Setting them to the same default as elastic
   * deform triscale grab because they work well in most cases. */
  const float force = 1.0f;
  const float shear_modulus = 1.0f;
  const float poisson_ratio = 0.4f;
  BKE_kelvinlet_init_params(
      &params, data->elastic_transform_radius, force, shear_modulus, poisson_ratio);

  SCULPT_undo_push_node(data->ob, node, SCULPT_UNDO_COORDS);

  PBVHVertexIter vd;
  BKE_pbvh_vertex_iter_begin (ss->pbvh, node, vd, PBVH_ITER_UNIQUE) {
    SCULPT_orig_vert_data_update(&orig_data, &vd);
    float transformed_co[3], orig_co[3], disp[3];
    const float fade = vd.mask ? *vd.mask : 0.0f;
    copy_v3_v3(orig_co, orig_data.co);

    copy_v3_v3(transformed_co, vd.co);
    mul_m4_v3(data->elastic_transform_mat, transformed_co);
    sub_v3_v3v3(disp, transformed_co, vd.co);

    float final_disp[3];
    BKE_kelvinlet_grab_triscale(final_disp, &params, vd.co, data->elastic_transform_pivot, disp);
    mul_v3_fl(final_disp, 20.0f * (1.0f - fade));

    copy_v3_v3(proxy[vd.i], final_disp);

    if (vd.mvert) {
      BKE_pbvh_vert_tag_update_normal(ss->pbvh, vd.vertex);
    }
  }
  BKE_pbvh_vertex_iter_end;

  BKE_pbvh_node_mark_update(node);
}

static void sculpt_transform_radius_elastic(Sculpt *sd, Object *ob, const float transform_radius)
{
  SculptSession *ss = ob->sculpt;
  BLI_assert(ss->filter_cache->transform_displacement_mode ==
             SCULPT_TRANSFORM_DISPLACEMENT_INCREMENTAL);

  const char symm = SCULPT_mesh_symmetry_xyz_get(ob);

  SculptThreadedTaskData data = {
      .sd = sd,
      .ob = ob,
      .nodes = ss->filter_cache->nodes,
      .elastic_transform_radius = transform_radius,
  };

  sculpt_transform_matrices_init(
      ss, symm, ss->filter_cache->transform_displacement_mode, data.transform_mats);

  TaskParallelSettings settings;
  BKE_pbvh_parallel_range_settings(&settings, true, ss->filter_cache->totnode);

  /* Elastic transform needs to apply all transform matrices to all vertices and then combine the
   * displacement proxies as all vertices are modified by all symmetry passes. */
  for (ePaintSymmetryFlags symmpass = 0; symmpass <= symm; symmpass++) {
    if (SCULPT_is_symmetry_iteration_valid(symmpass, symm)) {
      flip_v3_v3(data.elastic_transform_pivot, ss->pivot_pos, symmpass);
      flip_v3_v3(data.elastic_transform_pivot_init, ss->init_pivot_pos, symmpass);

      const int symm_area = SCULPT_get_vertex_symm_area(data.elastic_transform_pivot);
      copy_m4_m4(data.elastic_transform_mat, data.transform_mats[symm_area]);
      BLI_task_parallel_range(
          0, ss->filter_cache->totnode, &data, sculpt_elastic_transform_task_cb, &settings);
    }
  }
  SCULPT_combine_transform_proxies(sd, ob);
}

void ED_sculpt_update_modal_transform(struct bContext *C, Object *ob)
{
  Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
  SculptSession *ss = ob->sculpt;
  Depsgraph *depsgraph = CTX_data_depsgraph_pointer(C);

  SCULPT_vertex_random_access_ensure(ss);
  BKE_sculpt_update_object_for_edit(depsgraph, ob, false, false, false);

  switch (sd->transform_mode) {
    case SCULPT_TRANSFORM_MODE_ALL_VERTICES: {
      sculpt_transform_all_vertices(sd, ob);
      break;
    }
    case SCULPT_TRANSFORM_MODE_RADIUS_ELASTIC: {
      Brush *brush = BKE_paint_brush(&sd->paint);
      Scene *scene = CTX_data_scene(C);
      float transform_radius;

      if (BKE_brush_use_locked_size(scene, brush)) {
        transform_radius = BKE_brush_unprojected_radius_get(scene, brush);
      }
      else {
        ViewContext vc;

        ED_view3d_viewcontext_init(C, &vc, depsgraph);

        transform_radius = paint_calc_object_space_radius(
            &vc, ss->init_pivot_pos, BKE_brush_size_get(scene, brush));
      }

      sculpt_transform_radius_elastic(sd, ob, transform_radius);
      break;
    }
  }

  copy_v3_v3(ss->prev_pivot_pos, ss->pivot_pos);
  copy_v4_v4(ss->prev_pivot_rot, ss->pivot_rot);
  copy_v3_v3(ss->prev_pivot_scale, ss->pivot_scale);

  if (ss->deform_modifiers_active || ss->shapekey_active) {
    SCULPT_flush_stroke_deform(sd, ob, true);
  }

  SCULPT_flush_update_step(C, SCULPT_UPDATE_COORDS);
}

void ED_sculpt_end_transform(struct bContext *C, Object *ob)
{
  SculptSession *ss = ob->sculpt;
  if (ss->filter_cache) {
    SCULPT_filter_cache_free(ss);
  }
  SCULPT_flush_update_done(C, ob, SCULPT_UPDATE_COORDS);
}

typedef enum eSculptPivotPositionModes {
  SCULPT_PIVOT_POSITION_ORIGIN = 0,
  SCULPT_PIVOT_POSITION_UNMASKED = 1,
  SCULPT_PIVOT_POSITION_MASK_BORDER = 2,
  SCULPT_PIVOT_POSITION_ACTIVE_VERTEX = 3,
  SCULPT_PIVOT_POSITION_CURSOR_SURFACE = 4,
} eSculptPivotPositionModes;

static EnumPropertyItem prop_sculpt_pivot_position_types[] = {
    {SCULPT_PIVOT_POSITION_ORIGIN,
     "ORIGIN",
     0,
     "Origin",
     "Sets the pivot to the origin of the sculpt"},
    {SCULPT_PIVOT_POSITION_UNMASKED,
     "UNMASKED",
     0,
     "Unmasked",
     "Sets the pivot position to the average position of the unmasked vertices"},
    {SCULPT_PIVOT_POSITION_MASK_BORDER,
     "BORDER",
     0,
     "Mask Border",
     "Sets the pivot position to the center of the border of the mask"},
    {SCULPT_PIVOT_POSITION_ACTIVE_VERTEX,
     "ACTIVE",
     0,
     "Active Vertex",
     "Sets the pivot position to the active vertex position"},
    {SCULPT_PIVOT_POSITION_CURSOR_SURFACE,
     "SURFACE",
     0,
     "Surface",
     "Sets the pivot position to the surface under the cursor"},
    {0, NULL, 0, NULL, NULL},
};

static int sculpt_set_pivot_position_exec(bContext *C, wmOperator *op)
{
  Object *ob = CTX_data_active_object(C);
  SculptSession *ss = ob->sculpt;
  ARegion *region = CTX_wm_region(C);
  Depsgraph *depsgraph = CTX_data_ensure_evaluated_depsgraph(C);
  const char symm = SCULPT_mesh_symmetry_xyz_get(ob);

  int mode = RNA_enum_get(op->ptr, "mode");

  BKE_sculpt_update_object_for_edit(depsgraph, ob, false, true, false);

  /* Pivot to center. */
  if (mode == SCULPT_PIVOT_POSITION_ORIGIN) {
    zero_v3(ss->pivot_pos);
  }
  /* Pivot to active vertex. */
  else if (mode == SCULPT_PIVOT_POSITION_ACTIVE_VERTEX) {
    copy_v3_v3(ss->pivot_pos, SCULPT_active_vertex_co_get(ss));
  }
  /* Pivot to ray-cast surface. */
  else if (mode == SCULPT_PIVOT_POSITION_CURSOR_SURFACE) {
    float stroke_location[3];
    const float mval[2] = {
        RNA_float_get(op->ptr, "mouse_x"),
        RNA_float_get(op->ptr, "mouse_y"),
    };
    if (SCULPT_stroke_get_location(C, stroke_location, mval, false)) {
      copy_v3_v3(ss->pivot_pos, stroke_location);
    }
  }
  else {
    PBVHNode **nodes;
    int totnode;
    BKE_pbvh_search_gather(ss->pbvh, NULL, NULL, &nodes, &totnode);

    float avg[3];
    int total = 0;
    zero_v3(avg);

    /* Pivot to unmasked. */
    if (mode == SCULPT_PIVOT_POSITION_UNMASKED) {
      for (int n = 0; n < totnode; n++) {
        PBVHVertexIter vd;
        BKE_pbvh_vertex_iter_begin (ss->pbvh, nodes[n], vd, PBVH_ITER_UNIQUE) {
          const float mask = (vd.mask) ? *vd.mask : 0.0f;
          if (mask < 1.0f) {
            if (SCULPT_check_vertex_pivot_symmetry(vd.co, ss->pivot_pos, symm)) {
              add_v3_v3(avg, vd.co);
              total++;
            }
          }
        }
        BKE_pbvh_vertex_iter_end;
      }
    }
    /* Pivot to mask border. */
    else if (mode == SCULPT_PIVOT_POSITION_MASK_BORDER) {
      const float threshold = 0.2f;

      for (int n = 0; n < totnode; n++) {
        PBVHVertexIter vd;
        BKE_pbvh_vertex_iter_begin (ss->pbvh, nodes[n], vd, PBVH_ITER_UNIQUE) {
          const float mask = (vd.mask) ? *vd.mask : 0.0f;
          if (mask < (0.5f + threshold) && mask > (0.5f - threshold)) {
            if (SCULPT_check_vertex_pivot_symmetry(vd.co, ss->pivot_pos, symm)) {
              add_v3_v3(avg, vd.co);
              total++;
            }
          }
        }
        BKE_pbvh_vertex_iter_end;
      }
    }

    if (total > 0) {
      mul_v3_fl(avg, 1.0f / total);
      copy_v3_v3(ss->pivot_pos, avg);
    }

    MEM_SAFE_FREE(nodes);
  }

  /* Update the viewport navigation rotation origin. */
  UnifiedPaintSettings *ups = &CTX_data_tool_settings(C)->unified_paint_settings;
  copy_v3_v3(ups->average_stroke_accum, ss->pivot_pos);
  ups->average_stroke_counter = 1;
  ups->last_stroke_valid = true;

  ED_region_tag_redraw(region);
  WM_event_add_notifier(C, NC_GEOM | ND_SELECT, ob->data);

  return OPERATOR_FINISHED;
}

static int sculpt_set_pivot_position_invoke(bContext *C, wmOperator *op, const wmEvent *event)
{
  RNA_float_set(op->ptr, "mouse_x", event->mval[0]);
  RNA_float_set(op->ptr, "mouse_y", event->mval[1]);
  return sculpt_set_pivot_position_exec(C, op);
}

void SCULPT_OT_set_pivot_position(wmOperatorType *ot)
{
  /* Identifiers. */
  ot->name = "Set Pivot Position";
  ot->idname = "SCULPT_OT_set_pivot_position";
  ot->description = "Sets the sculpt transform pivot position";

  /* API callbacks. */
  ot->invoke = sculpt_set_pivot_position_invoke;
  ot->exec = sculpt_set_pivot_position_exec;
  ot->poll = SCULPT_mode_poll;

  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
  RNA_def_enum(ot->srna,
               "mode",
               prop_sculpt_pivot_position_types,
               SCULPT_PIVOT_POSITION_UNMASKED,
               "Mode",
               "");

  RNA_def_float(ot->srna,
                "mouse_x",
                0.0f,
                0.0f,
                FLT_MAX,
                "Mouse Position X",
                "Position of the mouse used for \"Surface\" mode",
                0.0f,
                10000.0f);
  RNA_def_float(ot->srna,
                "mouse_y",
                0.0f,
                0.0f,
                FLT_MAX,
                "Mouse Position Y",
                "Position of the mouse used for \"Surface\" mode",
                0.0f,
                10000.0f);
}
