/*
 * 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 bke
 */

#include "MEM_guardedalloc.h"

#include <float.h>

#include "DNA_curve_types.h"
#include "DNA_key_types.h"
#include "DNA_object_types.h"

#include "BLI_math_vector.h"

#include "BKE_anim_path.h"
#include "BKE_curve.h"
#include "BKE_key.h"

#include "CLG_log.h"

static CLG_LogRef LOG = {"bke.anim"};

/* ******************************************************************** */
/* Curve Paths - for curve deforms and/or curve following */

/**
 * Free curve path data
 *
 * \note Frees the path itself!
 * \note This is increasingly inaccurate with non-uniform #BevPoint subdivisions T24633.
 */
void free_path(Path *path)
{
  if (path->data) {
    MEM_freeN(path->data);
  }
  MEM_freeN(path);
}

/**
 * Calculate a curve-deform path for a curve
 * - Only called from displist.c -> #do_makeDispListCurveTypes
 */
void calc_curvepath(Object *ob, ListBase *nurbs)
{
  BevList *bl;
  BevPoint *bevp, *bevpn, *bevpfirst, *bevplast;
  PathPoint *pp;
  Nurb *nu;
  Path *path;
  float *fp, *dist, *maxdist, xyz[3];
  float fac, d = 0, fac1, fac2;
  int a, tot, cycl = 0;

  /* in a path vertices are with equal differences: path->len = number of verts */
  /* NOW WITH BEVELCURVE!!! */

  if (ob == NULL || ob->type != OB_CURVE) {
    return;
  }

  if (ob->runtime.curve_cache->path) {
    free_path(ob->runtime.curve_cache->path);
  }
  ob->runtime.curve_cache->path = NULL;

  /* weak! can only use first curve */
  bl = ob->runtime.curve_cache->bev.first;
  if (bl == NULL || !bl->nr) {
    return;
  }

  nu = nurbs->first;

  ob->runtime.curve_cache->path = path = MEM_callocN(sizeof(Path), "calc_curvepath");

  /* if POLY: last vertice != first vertice */
  cycl = (bl->poly != -1);

  tot = cycl ? bl->nr : bl->nr - 1;

  path->len = tot + 1;
  /* Exception: vector handle paths and polygon paths should be subdivided
   * at least a factor resolution. */
  if (path->len < nu->resolu * SEGMENTSU(nu)) {
    path->len = nu->resolu * SEGMENTSU(nu);
  }

  dist = (float *)MEM_mallocN(sizeof(float) * (tot + 1), "calcpathdist");

  /* all lengths in *dist */
  bevp = bevpfirst = bl->bevpoints;
  fp = dist;
  *fp = 0.0f;
  for (a = 0; a < tot; a++) {
    fp++;
    if (cycl && a == tot - 1) {
      sub_v3_v3v3(xyz, bevpfirst->vec, bevp->vec);
    }
    else {
      sub_v3_v3v3(xyz, (bevp + 1)->vec, bevp->vec);
    }

    *fp = *(fp - 1) + len_v3(xyz);
    bevp++;
  }

  path->totdist = *fp;

  /* the path verts  in path->data */
  /* now also with TILT value */
  pp = path->data = (PathPoint *)MEM_callocN(sizeof(PathPoint) * path->len, "pathdata");

  bevp = bevpfirst;
  bevpn = bevp + 1;
  bevplast = bevpfirst + (bl->nr - 1);
  if (UNLIKELY(bevpn > bevplast)) {
    bevpn = cycl ? bevpfirst : bevplast;
  }
  fp = dist + 1;
  maxdist = dist + tot;
  fac = 1.0f / ((float)path->len - 1.0f);
  fac = fac * path->totdist;

  for (a = 0; a < path->len; a++) {

    d = ((float)a) * fac;

    /* we're looking for location (distance) 'd' in the array */
    if (LIKELY(tot > 0)) {
      while ((fp < maxdist) && (d >= *fp)) {
        fp++;
        if (bevp < bevplast) {
          bevp++;
        }
        bevpn = bevp + 1;
        if (UNLIKELY(bevpn > bevplast)) {
          bevpn = cycl ? bevpfirst : bevplast;
        }
      }

      fac1 = (*(fp)-d) / (*(fp) - *(fp - 1));
      fac2 = 1.0f - fac1;
    }
    else {
      fac1 = 1.0f;
      fac2 = 0.0f;
    }

    interp_v3_v3v3(pp->vec, bevp->vec, bevpn->vec, fac2);
    pp->vec[3] = fac1 * bevp->tilt + fac2 * bevpn->tilt;
    pp->radius = fac1 * bevp->radius + fac2 * bevpn->radius;
    pp->weight = fac1 * bevp->weight + fac2 * bevpn->weight;
    interp_qt_qtqt(pp->quat, bevp->quat, bevpn->quat, fac2);
    normalize_qt(pp->quat);

    pp++;
  }

  MEM_freeN(dist);
}

static int interval_test(const int min, const int max, int p1, const int cycl)
{
  if (cycl) {
    p1 = mod_i(p1 - min, (max - min + 1)) + min;
  }
  else {
    if (p1 < min) {
      p1 = min;
    }
    else if (p1 > max) {
      p1 = max;
    }
  }
  return p1;
}

/**
 * Calculate the deformation implied by the curve path at a given parametric position,
 * and returns whether this operation succeeded.
 *
 * \param ctime: Time is normalized range <0-1>.
 *
 * \return success.
 */
bool where_on_path(const Object *ob,
                   float ctime,
                   float r_vec[4],
                   float r_dir[3],
                   float r_quat[4],
                   float *r_radius,
                   float *r_weight)
{
  Curve *cu;
  const Nurb *nu;
  const BevList *bl;
  const Path *path;
  const PathPoint *pp, *p0, *p1, *p2, *p3;
  float fac;
  float data[4];
  int cycl = 0, s0, s1, s2, s3;
  const ListBase *nurbs;

  if (ob == NULL || ob->type != OB_CURVE) {
    return false;
  }
  cu = ob->data;
  if (ob->runtime.curve_cache == NULL || ob->runtime.curve_cache->path == NULL ||
      ob->runtime.curve_cache->path->data == NULL) {
    CLOG_WARN(&LOG, "no path!");
    return false;
  }
  path = ob->runtime.curve_cache->path;
  pp = path->data;

  /* test for cyclic */
  bl = ob->runtime.curve_cache->bev.first;
  if (!bl) {
    return false;
  }
  if (!bl->nr) {
    return false;
  }
  if (bl->poly > -1) {
    cycl = 1;
  }

  /* values below zero for non-cyclic curves give strange results */
  BLI_assert(cycl || ctime >= 0.0f);

  ctime *= (path->len - 1);

  s1 = (int)floor(ctime);
  fac = (float)(s1 + 1) - ctime;

  /* path->len is corrected for cyclic */
  s0 = interval_test(0, path->len - 1 - cycl, s1 - 1, cycl);
  s1 = interval_test(0, path->len - 1 - cycl, s1, cycl);
  s2 = interval_test(0, path->len - 1 - cycl, s1 + 1, cycl);
  s3 = interval_test(0, path->len - 1 - cycl, s1 + 2, cycl);

  p0 = pp + s0;
  p1 = pp + s1;
  p2 = pp + s2;
  p3 = pp + s3;

  /* NOTE: commented out for follow constraint
   *
   *       If it's ever be uncommented watch out for BKE_curve_deform_coords()
   *       which used to temporary set CU_FOLLOW flag for the curve and no
   *       longer does it (because of threading issues of such a thing.
   */
  // if (cu->flag & CU_FOLLOW) {

  key_curve_tangent_weights(1.0f - fac, data, KEY_BSPLINE);

  interp_v3_v3v3v3v3(r_dir, p0->vec, p1->vec, p2->vec, p3->vec, data);

  /* Make compatible with #vec_to_quat. */
  negate_v3(r_dir);
  //}

  nurbs = BKE_curve_editNurbs_get(cu);
  if (!nurbs) {
    nurbs = &cu->nurb;
  }
  nu = nurbs->first;

  /* make sure that first and last frame are included in the vectors here  */
  if (nu->type == CU_POLY) {
    key_curve_position_weights(1.0f - fac, data, KEY_LINEAR);
  }
  else if (nu->type == CU_BEZIER) {
    key_curve_position_weights(1.0f - fac, data, KEY_LINEAR);
  }
  else if (s0 == s1 || p2 == p3) {
    key_curve_position_weights(1.0f - fac, data, KEY_CARDINAL);
  }
  else {
    key_curve_position_weights(1.0f - fac, data, KEY_BSPLINE);
  }

  r_vec[0] = /* X */
      data[0] * p0->vec[0] + data[1] * p1->vec[0] + data[2] * p2->vec[0] + data[3] * p3->vec[0];
  r_vec[1] = /* Y */
      data[0] * p0->vec[1] + data[1] * p1->vec[1] + data[2] * p2->vec[1] + data[3] * p3->vec[1];
  r_vec[2] = /* Z */
      data[0] * p0->vec[2] + data[1] * p1->vec[2] + data[2] * p2->vec[2] + data[3] * p3->vec[2];
  r_vec[3] = /* Tilt, should not be needed since we have quat still used */
      data[0] * p0->vec[3] + data[1] * p1->vec[3] + data[2] * p2->vec[3] + data[3] * p3->vec[3];

  if (r_quat) {
    float totfac, q1[4], q2[4];

    totfac = data[0] + data[3];
    if (totfac > FLT_EPSILON) {
      interp_qt_qtqt(q1, p0->quat, p3->quat, data[3] / totfac);
    }
    else {
      copy_qt_qt(q1, p1->quat);
    }

    totfac = data[1] + data[2];
    if (totfac > FLT_EPSILON) {
      interp_qt_qtqt(q2, p1->quat, p2->quat, data[2] / totfac);
    }
    else {
      copy_qt_qt(q2, p3->quat);
    }

    totfac = data[0] + data[1] + data[2] + data[3];
    if (totfac > FLT_EPSILON) {
      interp_qt_qtqt(r_quat, q1, q2, (data[1] + data[2]) / totfac);
    }
    else {
      copy_qt_qt(r_quat, q2);
    }
  }

  if (r_radius) {
    *r_radius = data[0] * p0->radius + data[1] * p1->radius + data[2] * p2->radius +
                data[3] * p3->radius;
  }

  if (r_weight) {
    *r_weight = data[0] * p0->weight + data[1] * p1->weight + data[2] * p2->weight +
                data[3] * p3->weight;
  }

  return true;
}