/*
 * 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) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 */

/** \file
 * \ingroup edlattice
 */

#include "MEM_guardedalloc.h"

#include "BLI_math.h"
#include "BLI_utildefines.h"

#include "DNA_curve_types.h"
#include "DNA_lattice_types.h"
#include "DNA_object_types.h"
#include "DNA_scene_types.h"

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

#include "BKE_context.h"
#include "BKE_lattice.h"
#include "BKE_layer.h"

#include "DEG_depsgraph.h"

#include "ED_screen.h"

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

#include "lattice_intern.h"

/** \} */

/* -------------------------------------------------------------------- */
/** \name Make Regular Operator
 * \{ */

static bool make_regular_poll(bContext *C)
{
  Object *ob;

  if (ED_operator_editlattice(C)) {
    return 1;
  }

  ob = CTX_data_active_object(C);
  return (ob && ob->type == OB_LATTICE);
}

static int make_regular_exec(bContext *C, wmOperator *UNUSED(op))
{
  ViewLayer *view_layer = CTX_data_view_layer(C);
  View3D *v3d = CTX_wm_view3d(C);
  const bool is_editmode = CTX_data_edit_object(C) != NULL;

  if (is_editmode) {
    uint objects_len;
    Object **objects = BKE_view_layer_array_from_objects_in_edit_mode_unique_data(
        view_layer, CTX_wm_view3d(C), &objects_len);
    for (uint ob_index = 0; ob_index < objects_len; ob_index++) {
      Object *ob = objects[ob_index];
      Lattice *lt = ob->data;

      if (lt->editlatt->latt == NULL) {
        continue;
      }

      BKE_lattice_resize(lt->editlatt->latt, lt->pntsu, lt->pntsv, lt->pntsw, NULL);

      DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
      WM_event_add_notifier(C, NC_GEOM | ND_DATA, ob->data);
    }
    MEM_freeN(objects);
  }
  else {
    FOREACH_SELECTED_OBJECT_BEGIN (view_layer, v3d, ob) {
      if (ob->type != OB_LATTICE) {
        continue;
      }

      Lattice *lt = ob->data;
      BKE_lattice_resize(lt, lt->pntsu, lt->pntsv, lt->pntsw, NULL);

      DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
      WM_event_add_notifier(C, NC_GEOM | ND_DATA, ob->data);
    }
    FOREACH_SELECTED_OBJECT_END;
  }
  return OPERATOR_FINISHED;
}

void LATTICE_OT_make_regular(wmOperatorType *ot)
{
  /* identifiers */
  ot->name = "Make Regular";
  ot->description = "Set UVW control points a uniform distance apart";
  ot->idname = "LATTICE_OT_make_regular";

  /* api callbacks */
  ot->exec = make_regular_exec;
  ot->poll = make_regular_poll;

  /* flags */
  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Flip Verts Operator
 * \{ */

/* flipping options */
typedef enum eLattice_FlipAxes {
  LATTICE_FLIP_U = 0,
  LATTICE_FLIP_V = 1,
  LATTICE_FLIP_W = 2,
} eLattice_FlipAxes;

/**
 * Flip midpoint value so that relative distances between midpoint and neighbor-pair is maintained.
 * Assumes that uvw <=> xyz (i.e. axis-aligned index-axes with coordinate-axes).
 * - Helper for #lattice_flip_exec()
 */
static void lattice_flip_point_value(
    Lattice *lt, int u, int v, int w, float mid, eLattice_FlipAxes axis)
{
  BPoint *bp;
  float diff;

  /* just the point in the middle (unpaired) */
  bp = &lt->def[BKE_lattice_index_from_uvw(lt, u, v, w)];

  /* flip over axis */
  diff = mid - bp->vec[axis];
  bp->vec[axis] = mid + diff;
}

/**
 * Swap pairs of lattice points along a specified axis.
 * - Helper for #lattice_flip_exec()
 */
static void lattice_swap_point_pairs(
    Lattice *lt, int u, int v, int w, float mid, eLattice_FlipAxes axis)
{
  BPoint *bpA, *bpB;

  int numU = lt->pntsu;
  int numV = lt->pntsv;
  int numW = lt->pntsw;

  int u0 = u, u1 = u;
  int v0 = v, v1 = v;
  int w0 = w, w1 = w;

  /* get pair index by just overriding the relevant pair-value
   * - "-1" else buffer overflow
   */
  switch (axis) {
    case LATTICE_FLIP_U:
      u1 = numU - u - 1;
      break;
    case LATTICE_FLIP_V:
      v1 = numV - v - 1;
      break;
    case LATTICE_FLIP_W:
      w1 = numW - w - 1;
      break;
  }

  /* get points to operate on */
  bpA = &lt->def[BKE_lattice_index_from_uvw(lt, u0, v0, w0)];
  bpB = &lt->def[BKE_lattice_index_from_uvw(lt, u1, v1, w1)];

  /* Swap all coordinates, so that flipped coordinates belong to
   * the indices on the correct side of the lattice.
   *
   *   Coords:  (-2 4) |0| (3 4)   --> (3 4) |0| (-2 4)
   *   Indices:  (0,L)     (1,R)   --> (0,L)     (1,R)
   */
  swap_v3_v3(bpA->vec, bpB->vec);

  /* However, we need to mirror the coordinate values on the axis we're dealing with,
   * otherwise we'd have effectively only rotated the points around. If we don't do this,
   * we'd just be reimplementing the naive mirroring algorithm, which causes unwanted deforms
   * such as flipped normals, etc.
   *
   *   Coords:  (3 4) |0| (-2 4)  --\
   *                                 \-> (-3 4) |0| (2 4)
   *   Indices: (0,L)     (1,R)   -->     (0,L)     (1,R)
   */
  lattice_flip_point_value(lt, u0, v0, w0, mid, axis);
  lattice_flip_point_value(lt, u1, v1, w1, mid, axis);
}

static int lattice_flip_exec(bContext *C, wmOperator *op)
{
  ViewLayer *view_layer = CTX_data_view_layer(C);
  uint objects_len;
  bool changed = false;
  const eLattice_FlipAxes axis = RNA_enum_get(op->ptr, "axis");

  Object **objects = BKE_view_layer_array_from_objects_in_edit_mode_unique_data(
      view_layer, CTX_wm_view3d(C), &objects_len);
  for (uint ob_index = 0; ob_index < objects_len; ob_index++) {
    Object *obedit = objects[ob_index];
    Lattice *lt;

    int numU, numV, numW;
    int totP;

    float mid = 0.0f;
    short isOdd = 0;

    /* get lattice - we need the "edit lattice" from the lattice... confusing... */
    lt = (Lattice *)obedit->data;
    lt = lt->editlatt->latt;

    numU = lt->pntsu;
    numV = lt->pntsv;
    numW = lt->pntsw;
    totP = numU * numV * numW;

    /* First Pass: determine midpoint - used for flipping center verts if there
     * are odd number of points on axis */
    switch (axis) {
      case LATTICE_FLIP_U:
        isOdd = numU & 1;
        break;
      case LATTICE_FLIP_V:
        isOdd = numV & 1;
        break;
      case LATTICE_FLIP_W:
        isOdd = numW & 1;
        break;

      default:
        printf("lattice_flip(): Unknown flipping axis (%u)\n", axis);
        return OPERATOR_CANCELLED;
    }

    if (isOdd) {
      BPoint *bp;
      float avgInv = 1.0f / (float)totP;
      int i;

      /* midpoint calculation - assuming that u/v/w are axis-aligned */
      for (i = 0, bp = lt->def; i < totP; i++, bp++) {
        mid += bp->vec[axis] * avgInv;
      }
    }

    /* Second Pass: swap pairs of vertices per axis, assuming they are all sorted */
    switch (axis) {
      case LATTICE_FLIP_U: {
        int u, v, w;

        /* v/w strips - front to back, top to bottom */
        for (w = 0; w < numW; w++) {
          for (v = 0; v < numV; v++) {
            /* swap coordinates of pairs of vertices on u */
            for (u = 0; u < (numU / 2); u++) {
              lattice_swap_point_pairs(lt, u, v, w, mid, axis);
            }

            /* flip u-coordinate of midpoint (i.e. unpaired point on u) */
            if (isOdd) {
              u = (numU / 2);
              lattice_flip_point_value(lt, u, v, w, mid, axis);
            }
          }
        }
        break;
      }
      case LATTICE_FLIP_V: {
        int u, v, w;

        /* u/w strips - front to back, left to right */
        for (w = 0; w < numW; w++) {
          for (u = 0; u < numU; u++) {
            /* swap coordinates of pairs of vertices on v */
            for (v = 0; v < (numV / 2); v++) {
              lattice_swap_point_pairs(lt, u, v, w, mid, axis);
            }

            /* flip v-coordinate of midpoint (i.e. unpaired point on v) */
            if (isOdd) {
              v = (numV / 2);
              lattice_flip_point_value(lt, u, v, w, mid, axis);
            }
          }
        }
        break;
      }
      case LATTICE_FLIP_W: {
        int u, v, w;

        for (v = 0; v < numV; v++) {
          for (u = 0; u < numU; u++) {
            /* swap coordinates of pairs of vertices on w */
            for (w = 0; w < (numW / 2); w++) {
              lattice_swap_point_pairs(lt, u, v, w, mid, axis);
            }

            /* flip w-coordinate of midpoint (i.e. unpaired point on w) */
            if (isOdd) {
              w = (numW / 2);
              lattice_flip_point_value(lt, u, v, w, mid, axis);
            }
          }
        }
        break;
      }
      default: /* shouldn't happen, but just in case */
        break;
    }

    /* updates */
    DEG_id_tag_update(&obedit->id, ID_RECALC_GEOMETRY);
    WM_event_add_notifier(C, NC_GEOM | ND_DATA, obedit->data);
    changed = true;
  }
  MEM_freeN(objects);

  return changed ? OPERATOR_FINISHED : OPERATOR_CANCELLED;
}

void LATTICE_OT_flip(wmOperatorType *ot)
{
  static const EnumPropertyItem flip_items[] = {
      {LATTICE_FLIP_U, "U", 0, "U (X) Axis", ""},
      {LATTICE_FLIP_V, "V", 0, "V (Y) Axis", ""},
      {LATTICE_FLIP_W, "W", 0, "W (Z) Axis", ""},
      {0, NULL, 0, NULL, NULL},
  };

  /* identifiers */
  ot->name = "Flip (Distortion Free)";
  ot->description = "Mirror all control points without inverting the lattice deform";
  ot->idname = "LATTICE_OT_flip";

  /* api callbacks */
  ot->poll = ED_operator_editlattice;
  ot->invoke = WM_menu_invoke;
  ot->exec = lattice_flip_exec;

  /* flags */
  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

  /* properties */
  ot->prop = RNA_def_enum(ot->srna,
                          "axis",
                          flip_items,
                          LATTICE_FLIP_U,
                          "Flip Axis",
                          "Coordinates along this axis get flipped");
}

/** \} */