/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#ifndef itkQuadEdgeMeshBaseIterator_h
#define itkQuadEdgeMeshBaseIterator_h

#include "itkMacro.h"

// -------------------------------------------------------------------------
#define itkQEDefineIteratorMethodsMacro(Op)                                                                        \
  virtual Iterator Begin##Op() { return Iterator(this, Self::Iterator::Operator##Op, true); }                      \
                                                                                                                   \
  virtual ConstIterator Begin##Op() const { return ConstIterator(this, Self::ConstIterator::Operator##Op, true); } \
                                                                                                                   \
  virtual Iterator End##Op() { return Iterator(this, Self::Iterator::Operator##Op, false); }                       \
                                                                                                                   \
  virtual ConstIterator End##Op() const { return ConstIterator(this, Self::ConstIterator::Operator##Op, false); }  \
  ITK_MACROEND_NOOP_STATEMENT

// -------------------------------------------------------------------------
#define itkQEDefineIteratorGeomMethodsMacro(Op)                                                               \
  virtual IteratorGeom BeginGeom##Op() { return IteratorGeom(this, Self::IteratorGeom::Operator##Op, true); } \
                                                                                                              \
  virtual ConstIteratorGeom BeginGeom##Op() const                                                             \
  {                                                                                                           \
    return ConstIteratorGeom(this, Self::ConstIteratorGeom::Operator##Op, true);                              \
  }                                                                                                           \
                                                                                                              \
  virtual IteratorGeom EndGeom##Op() { return IteratorGeom(this, Self::IteratorGeom::Operator##Op, false); }  \
                                                                                                              \
  virtual ConstIteratorGeom EndGeom##Op() const                                                               \
  {                                                                                                           \
    return ConstIteratorGeom(this, Self::ConstIteratorGeom::Operator##Op, false);                             \
  }                                                                                                           \
  ITK_MACROEND_NOOP_STATEMENT

namespace itk
{
/**
 * \class QuadEdgeMeshBaseIterator
 *
 * \brief Base iterator class for QuadEdgeMesh
 * \ingroup ITKQuadEdgeMesh
 */
template <typename TQuadEdge>
class QuadEdgeMeshBaseIterator
{
public:
  // Hierarchy type alias & values.
  using Self = QuadEdgeMeshBaseIterator;
  using QuadEdgeType = TQuadEdge;

  // Different types of iterators, one for each basic QE operation.
  enum
  {
    OperatorOnext = 0,
    OperatorSym = 1,
    OperatorLnext = 2,
    OperatorRnext = 3,
    OperatorDnext = 4,
    OperatorOprev = 5,
    OperatorLprev = 6,
    OperatorRprev = 7,
    OperatorDprev = 8,
    OperatorInvOnext = 9,
    OperatorInvLnext = 10,
    OperatorInvRnext = 11,
    OperatorInvDnext = 12
  };

public:
  // Object creation methods.
  QuadEdgeMeshBaseIterator(QuadEdgeType * e, int op = OperatorOnext, bool start = true)
    : m_StartEdge(e)
    , m_Iterator(e)
    , m_OpType(op)
    , m_Start(start)
  {}

  QuadEdgeMeshBaseIterator(const QuadEdgeMeshBaseIterator &) = default;

  virtual ~QuadEdgeMeshBaseIterator() = default;

  Self &
  operator=(const Self & r)
  {
    if (this != &r)
    {
      m_StartEdge = r.m_StartEdge;
      m_Iterator = r.m_Iterator;
      m_OpType = r.m_OpType;
      m_Start = r.m_Start;
    }
    return *this;
  }

  [[nodiscard]] QuadEdgeType *
  GetStartEdge() const
  {
    return m_StartEdge;
  }
  [[nodiscard]] QuadEdgeType *
  GetIterator() const
  {
    return m_Iterator;
  }
  [[nodiscard]] int
  GetOpType() const
  {
    return m_OpType;
  }
  [[nodiscard]] bool
  GetStart() const
  {
    return m_Start;
  }

  /** Iteration methods. */
  bool
  operator==(const Self & r) const
  {
    return (m_StartEdge == r.m_StartEdge) && (m_Iterator == r.m_Iterator) && (m_OpType == r.m_OpType) &&
           (m_Start == r.m_Start);
  }

  ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION(Self);

  Self &
  operator++()
  {
    if (m_Start)
    {
      this->GoToNext();
      m_Start = !(m_Iterator == m_StartEdge);
    }

    return *this;
  }

  Self &
  operator++(int)
  {
    if (m_Start)
    {
      this->GoToNext();
      m_Start = !(m_Iterator == m_StartEdge);
    }
    return *this;
  }

protected:
  /** Method that should do all the iteration work. */
  virtual void
  GoToNext()
  {
    switch (m_OpType)
    {
      case OperatorOnext:
        m_Iterator = m_Iterator->GetOnext();
        break;
      case OperatorSym:
        m_Iterator = m_Iterator->GetSym();
        break;
      case OperatorLnext:
        m_Iterator = m_Iterator->GetLnext();
        break;
      case OperatorRnext:
        m_Iterator = m_Iterator->GetRnext();
        break;
      case OperatorDnext:
        m_Iterator = m_Iterator->GetDnext();
        break;
      case OperatorOprev:
        m_Iterator = m_Iterator->GetOprev();
        break;
      case OperatorLprev:
        m_Iterator = m_Iterator->GetLprev();
        break;
      case OperatorRprev:
        m_Iterator = m_Iterator->GetRprev();
        break;
      case OperatorDprev:
        m_Iterator = m_Iterator->GetDprev();
        break;
      case OperatorInvOnext:
        m_Iterator = m_Iterator->GetInvOnext();
        break;
      case OperatorInvLnext:
        m_Iterator = m_Iterator->GetInvLnext();
        break;
      case OperatorInvRnext:
        m_Iterator = m_Iterator->GetInvRnext();
        break;
      case OperatorInvDnext:
        m_Iterator = m_Iterator->GetInvDnext();
        break;
      default:
        break;
    }
  }

protected:
  QuadEdgeType * m_StartEdge{}; /**< Start edge */
  QuadEdgeType * m_Iterator{};  /**< Current iteration position */
  int            m_OpType{};    /**< Operation type */
  bool           m_Start{};     /**< Indicates iteration has just started */
};

/**
 * \class QuadEdgeMeshIterator
 *
 * \brief Non const iterator for QuadMesh
 * \ingroup ITKQuadEdgeMesh
 */
template <typename TQuadEdge>
class ITK_TEMPLATE_EXPORT QuadEdgeMeshIterator : public QuadEdgeMeshBaseIterator<TQuadEdge>
{
public:
  /** Hierarchy type alias and values. */
  using Self = QuadEdgeMeshIterator;
  using Superclass = QuadEdgeMeshBaseIterator<TQuadEdge>;
  using QuadEdgeType = TQuadEdge;

public:
  /** Object creation methods. */
  QuadEdgeMeshIterator(QuadEdgeType * e = (QuadEdgeType *)0, int op = Superclass::OperatorOnext, bool start = true)
    : Superclass(e, op, start)
  {}

  QuadEdgeMeshIterator(const QuadEdgeMeshIterator &) = default;

  ~QuadEdgeMeshIterator() override = default;

  QuadEdgeType *
  Value()
  {
    return this->m_Iterator;
  }
  [[nodiscard]] const QuadEdgeType *
  Value() const
  {
    return this->m_Iterator;
  }
};

/**
 * \class QuadEdgeMeshIteratorGeom
 *
 * \brief Non const geometrical iterator
 * \ingroup ITKQuadEdgeMesh
 */
template <typename TGeometricalQuadEdge>
class ITK_TEMPLATE_EXPORT QuadEdgeMeshIteratorGeom : public QuadEdgeMeshIterator<TGeometricalQuadEdge>
{
public:
  /** Hierarchy type alias and values. */
  using Superclass = QuadEdgeMeshIterator<TGeometricalQuadEdge>;
  using QuadEdgeType = TGeometricalQuadEdge;

  /** Geometric value type. */
  using OriginRefType = typename QuadEdgeType::OriginRefType;

public:
  QuadEdgeMeshIteratorGeom(QuadEdgeType * e = nullptr, int op = Superclass::OperatorOnext, bool start = true)
    : Superclass(e, op, start)
  {}

  QuadEdgeMeshIteratorGeom(const QuadEdgeMeshIteratorGeom &) = default;

  OriginRefType
  operator*()
  {
    return this->m_Iterator->GetOrigin();
  }
};

/**
 * \class QuadEdgeMeshConstIterator
 *
 * \brief Const iterator for QuadEdgeMesh
 * \ingroup ITKQuadEdgeMesh
 */
template <typename TQuadEdge>
class ITK_TEMPLATE_EXPORT QuadEdgeMeshConstIterator : public QuadEdgeMeshBaseIterator<TQuadEdge>
{
public:
  /** Hierarchy type alias & values. */
  using Self = QuadEdgeMeshConstIterator;
  using Superclass = QuadEdgeMeshBaseIterator<TQuadEdge>;
  using NoConstType = QuadEdgeMeshIterator<TQuadEdge>;
  using QuadEdgeType = TQuadEdge;

public:
  /** Object creation methods. */
  QuadEdgeMeshConstIterator(const QuadEdgeType * e = (QuadEdgeType *)0,
                            int                  op = Superclass::OperatorOnext,
                            bool                 start = true)
    : Superclass(const_cast<QuadEdgeType *>(e), op, start)
  {}

  QuadEdgeMeshConstIterator(const QuadEdgeMeshConstIterator &) = default;

  ~QuadEdgeMeshConstIterator() override = default;

  Self &
  operator=(const NoConstType & r)
  {
    this->m_StartEdge = r.GetStartEdge();
    this->m_Iterator = r.GetIterator();
    this->m_OpType = r.GetOpType();
    this->m_Start = r.GetStart();
    return *this;
  }

  [[nodiscard]] const QuadEdgeType *
  Value() const
  {
    return this->m_Iterator;
  }
};

/**
 * \class QuadEdgeMeshConstIteratorGeom
 *
 * \brief Const geometrical iterator
 * \ingroup ITKQuadEdgeMesh
 */
template <typename TGeometricalQuadEdge>
class ITK_TEMPLATE_EXPORT QuadEdgeMeshConstIteratorGeom : public QuadEdgeMeshConstIterator<TGeometricalQuadEdge>
{
public:
  /** Hierarchy type alias and values. */
  using Self = QuadEdgeMeshConstIteratorGeom;
  using Superclass = QuadEdgeMeshConstIterator<TGeometricalQuadEdge>;
  using NoConstType = QuadEdgeMeshIteratorGeom<TGeometricalQuadEdge>;
  using QuadEdgeType = TGeometricalQuadEdge;

  /** Geometric value type. */
  using OriginRefType = typename QuadEdgeType::OriginRefType;

public:
  QuadEdgeMeshConstIteratorGeom(const QuadEdgeType * e = (QuadEdgeType *)0,
                                int                  op = Superclass::OperatorOnext,
                                bool                 start = true)
    : Superclass(e, op, start)
  {}

  QuadEdgeMeshConstIteratorGeom(const QuadEdgeMeshConstIteratorGeom &) = default;

  ~QuadEdgeMeshConstIteratorGeom() override = default;

  Self &
  operator=(const NoConstType & r)
  {
    this->m_StartEdge = r.GetStartEdge();
    this->m_Iterator = r.GetIterator();
    this->m_OpType = r.GetOpType();
    this->m_Start = r.GetStart();
    return *this;
  }

  const OriginRefType
  operator*() const
  {
    return this->m_Iterator->GetOrigin();
  }
};
} // namespace itk

#endif
