/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

#pragma once

/** \file
 * \ingroup freestyle
 * \brief Iterators used to iterate over the elements of the Curve. Can't be used in python
 */

#include "CurveIterators.h"
#include "Stroke.h"

namespace Freestyle {

namespace CurveInternal {

class CurvePoint_const_traits : public Const_traits<CurvePoint *> {
 public:
  typedef deque<CurvePoint *> vertex_container;
  typedef vertex_container::const_iterator vertex_container_iterator;
  typedef SVertex vertex_type;
};

class CurvePoint_nonconst_traits : public Nonconst_traits<CurvePoint *> {
 public:
  typedef deque<CurvePoint *> vertex_container;
  typedef vertex_container::iterator vertex_container_iterator;
  typedef SVertex vertex_type;
};

/**********************************/
/*                                */
/*                                */
/*     CurvePoint Iterator        */
/*                                */
/*                                */
/**********************************/

/** iterator on a curve. Allows an iterating outside initial vertices. A CurvePoint is
 * instantiated and returned when the iterator is dereferenced.
 */
template<class Traits>
class __point_iterator : public IteratorBase<Traits, BidirectionalIteratorTag_Traits> {
 public:
  typedef __point_iterator<Traits> Self;
  typedef typename Traits::vertex_container_iterator vertex_container_iterator;
  typedef typename Traits::vertex_type vertex_type;
  typedef CurvePoint Point;
  typedef Point point_type;

  typedef __point_iterator<CurvePoint_nonconst_traits> iterator;
  typedef __point_iterator<CurvePoint_const_traits> const_iterator;

#if 0
  typedef Vertex vertex_type;
  typedef vertex_container_iterator vertex_iterator_type;
  typedef CurvePoint<Vertex> Point;
  typedef Point point_type;
#endif
  typedef IteratorBase<Traits, BidirectionalIteratorTag_Traits> parent_class;
#if 0
#  if defined(__GNUC__) && (__GNUC__ < 3)
  typedef bidirectional_iterator<CurvePoint<Vertex>, ptrdiff_t> bidirectional_point_iterator;
#  else
  typedef iterator<bidirectional_iterator_tag, CurvePoint<Vertex>, ptrdiff_t>
      bidirectional_point_iterator;
#  endif
#endif
  friend class Freestyle::Curve;
#if 0
  friend class Curve::vertex_iterator;
  friend class __point_iterator<CurvePoint_nonconst_traits>;
  friend class iterator;
#endif
  // protected:
 public:
  float _CurvilinearLength;
  float _step;
  vertex_container_iterator __A;
  vertex_container_iterator __B;
  vertex_container_iterator _begin;
  vertex_container_iterator _end;
  int _n;
  int _currentn;
  float _t;
  mutable Point *_Point;

 public:
  inline __point_iterator(float step = 0.0f) : parent_class()
  {
    _step = step;
    _CurvilinearLength = 0.0f;
    _t = 0.0f;
    _Point = 0;
    _n = 0;
    _currentn = 0;
  }

  inline __point_iterator(const iterator &iBrother) : parent_class()
  {
    __A = iBrother.__A;
    __B = iBrother.__B;
    _begin = iBrother._begin;
    _end = iBrother._end;
    _CurvilinearLength = iBrother._CurvilinearLength;
    _step = iBrother._step;
    _t = iBrother._t;
    if (iBrother._Point == 0) {
      _Point = 0;
    }
    else {
      _Point = new Point(*(iBrother._Point));
    }
    _n = iBrother._n;
    _currentn = iBrother._currentn;
  }

  inline __point_iterator(const const_iterator &iBrother) : parent_class()
  {
    __A = iBrother.__A;
    __B = iBrother.__B;
    _begin = iBrother._begin;
    _end = iBrother._end;
    _CurvilinearLength = iBrother._CurvilinearLength;
    _step = iBrother._step;
    _t = iBrother._t;
    if (iBrother._Point == 0) {
      _Point = 0;
    }
    else {
      _Point = new Point(*(iBrother._Point));
    }
    _n = iBrother._n;
    _currentn = iBrother._currentn;
  }

  inline Self &operator=(const Self &iBrother)
  {
    //((bidirectional_point_iterator*)this)->operator=(iBrother);
    __A = iBrother.__A;
    __B = iBrother.__B;
    _begin = iBrother._begin;
    _end = iBrother._end;
    _CurvilinearLength = iBrother._CurvilinearLength;
    _step = iBrother._step;
    _t = iBrother._t;
    if (iBrother._Point == 0) {
      _Point = 0;
    }
    else {
      _Point = new Point(*(iBrother._Point));
    }
    _n = iBrother._n;
    _currentn = iBrother._currentn;
    return *this;
  }

  virtual ~__point_iterator()
  {
    if (_Point != 0) {
      delete _Point;
    }
  }

  // protected:  //FIXME
 public:
  inline __point_iterator(vertex_container_iterator iA,
                          vertex_container_iterator iB,
                          vertex_container_iterator ibegin,
                          vertex_container_iterator iend,
                          int currentn,
                          int n,
                          float step,
                          float t = 0.0f,
                          float iCurvilinearLength = 0.0f)
      : parent_class()
  {
    __A = iA;
    __B = iB;
    _begin = ibegin;
    _end = iend;
    _CurvilinearLength = iCurvilinearLength;
    _step = step;
    _t = t;
    _Point = 0;
    _n = n;
    _currentn = currentn;
  }

 public:
  // operators
  inline Self &operator++()  // operator corresponding to ++i
  {
    increment();
    return *this;
  }

  /* Operator corresponding to i++, i.e. it returns the value *and then* increments.
   * That’s why we store the value in a temp.
   */
  inline Self operator++(int)
  {
    Self tmp = *this;
    increment();
    return tmp;
  }

  inline Self &operator--()  // operator corresponding to --i
  {
    decrement();
    return *this;
  }

  inline Self operator--(int)  // operator corresponding to i--
  {
    Self tmp = *this;
    decrement();
    return tmp;
  }

  // comparability
  virtual bool operator!=(const Self &b) const
  {
    return ((__A != b.__A) || (__B != b.__B) || (_t != b._t));
  }

  virtual bool operator==(const Self &b) const
  {
    return !(*this != b);
  }

  // dereferencing
  virtual typename Traits::reference operator*() const
  {
    if (_Point != 0) {
      delete _Point;
      _Point = 0;
    }
    if ((_currentn < 0) || (_currentn >= _n)) {
      return _Point;  // 0 in this case
    }
    return (_Point = new Point(*__A, *__B, _t));
  }

  virtual typename Traits::pointer operator->() const
  {
    return &(operator*());
  }

  virtual bool begin() const
  {
    if ((__A == _begin) && (_t < (float)M_EPSILON)) {
      return true;
    }
    return false;
  }

  virtual bool end() const
  {
    if ((__B == _end)) {
      return true;
    }
    return false;
  }

 protected:
  virtual void increment()
  {
    if (_Point != 0) {
      delete _Point;
      _Point = 0;
    }
    if ((_currentn == _n - 1) && (_t == 1.0f)) {
      // we're setting the iterator to end
      ++__A;
      ++__B;
      ++_currentn;
      _t = 0.0f;
      return;
    }

    if (0 == _step) {  // means we iterate over initial vertices
      Vec3r vec_tmp((*__B)->point2d() - (*__A)->point2d());
      _CurvilinearLength += vec_tmp.norm();
      if (_currentn == _n - 1) {
        _t = 1.0f;
        return;
      }
      ++__B;
      ++__A;
      ++_currentn;
      return;
    }

    // compute the new position:
    Vec3r vec_tmp2((*__A)->point2d() - (*__B)->point2d());
    float normAB = vec_tmp2.norm();

    if (normAB > M_EPSILON) {
      _CurvilinearLength += _step;
      _t = _t + _step / normAB;
    }
    else {
      _t = 1.0f;  // AB is a null segment, we're directly at its end
    }
    // if normAB ~= 0, we don't change these values
    if (_t >= 1) {
      _CurvilinearLength -= normAB * (_t - 1);
      if (_currentn == _n - 1) {
        _t = 1.0f;
      }
      else {
        _t = 0.0f;
        ++_currentn;
        ++__A;
        ++__B;
      }
    }
  }

  virtual void decrement()
  {
    if (_Point != 0) {
      delete _Point;
      _Point = 0;
    }

    if (_t == 0.0f) {  // we're at the beginning of the edge
      _t = 1.0f;
      --_currentn;
      --__A;
      --__B;
      if (_currentn == _n - 1) {
        return;
      }
    }

    if (0 == _step) {  // means we iterate over initial vertices
      Vec3r vec_tmp((*__B)->point2d() - (*__A)->point2d());
      _CurvilinearLength -= vec_tmp.norm();
      _t = 0;
      return;
    }

    // compute the new position:
    Vec3r vec_tmp2((*__A)->point2d() - (*__B)->point2d());
    float normAB = vec_tmp2.norm();

    if (normAB > M_EPSILON) {
      _CurvilinearLength -= _step;
      _t = _t - _step / normAB;
    }
    else {
      _t = -1.0f;  // We just need a negative value here
    }

    // round value
    if (fabs(_t) < (float)M_EPSILON) {
      _t = 0.0f;
    }
    if (_t < 0) {
      if (_currentn == 0) {
        _CurvilinearLength = 0.0f;
      }
      else {
        _CurvilinearLength += normAB * (-_t);
      }
      _t = 0.0f;
    }
  }
};

}  // end of namespace CurveInternal

} /* namespace Freestyle */
