// Boost.Geometry Index
//
// R-tree query iterators
//
// Copyright (c) 2011-2023 Adam Wulkiewicz, Lodz, Poland.
//
// This file was modified by Oracle on 2019-2021.
// Modifications copyright (c) 2019-2021 Oracle and/or its affiliates.
// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
//
// Use, modification and distribution is subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

#ifndef BOOST_GEOMETRY_INDEX_DETAIL_RTREE_QUERY_ITERATORS_HPP
#define BOOST_GEOMETRY_INDEX_DETAIL_RTREE_QUERY_ITERATORS_HPP

#include <memory>

#include <boost/geometry/index/detail/rtree/node/node_elements.hpp>
#include <boost/geometry/index/detail/rtree/visitors/distance_query.hpp>
#include <boost/geometry/index/detail/rtree/visitors/spatial_query.hpp>

namespace boost { namespace geometry { namespace index { namespace detail { namespace rtree { namespace iterators {

template <typename Value, typename Allocators>
struct end_query_iterator
{
    typedef std::forward_iterator_tag iterator_category;
    typedef Value value_type;
    typedef typename Allocators::const_reference reference;
    typedef typename Allocators::difference_type difference_type;
    typedef typename Allocators::const_pointer pointer;

    reference operator*() const
    {
        BOOST_GEOMETRY_INDEX_ASSERT(false, "iterator not dereferencable");
        pointer p(0);
        return *p;
    }

    const value_type * operator->() const
    {
        BOOST_GEOMETRY_INDEX_ASSERT(false, "iterator not dereferencable");
        const value_type * p = 0;
        return p;
    }

    end_query_iterator & operator++()
    {
        BOOST_GEOMETRY_INDEX_ASSERT(false, "iterator not incrementable");
        return *this;
    }

    end_query_iterator operator++(int)
    {
        BOOST_GEOMETRY_INDEX_ASSERT(false, "iterator not incrementable");
        return *this;
    }

    friend bool operator==(end_query_iterator const& /*l*/, end_query_iterator const& /*r*/)
    {
        return true;
    }
};

template <typename MembersHolder, typename Predicates>
class spatial_query_iterator
{
    typedef typename MembersHolder::allocators_type allocators_type;

public:
    typedef std::forward_iterator_tag iterator_category;
    typedef typename MembersHolder::value_type value_type;
    typedef typename allocators_type::const_reference reference;
    typedef typename allocators_type::difference_type difference_type;
    typedef typename allocators_type::const_pointer pointer;

    spatial_query_iterator() = default;

    explicit spatial_query_iterator(Predicates const& pred)
        : m_impl(pred)
    {}

    spatial_query_iterator(MembersHolder const& members, Predicates const& pred)
        : m_impl(members, pred)
    {
        m_impl.initialize(members);
    }

    reference operator*() const
    {
        return m_impl.dereference();
    }

    const value_type * operator->() const
    {
        return boost::addressof(m_impl.dereference());
    }

    spatial_query_iterator & operator++()
    {
        m_impl.increment();
        return *this;
    }

    spatial_query_iterator operator++(int)
    {
        spatial_query_iterator temp = *this;
        this->operator++();
        return temp;
    }

    friend bool operator==(spatial_query_iterator const& l, spatial_query_iterator const& r)
    {
        return l.m_impl == r.m_impl;
    }

    friend bool operator==(spatial_query_iterator const& l, end_query_iterator<value_type, allocators_type> const& /*r*/)
    {
        return l.m_impl.is_end();
    }

    friend bool operator==(end_query_iterator<value_type, allocators_type> const& /*l*/, spatial_query_iterator const& r)
    {
        return r.m_impl.is_end();
    }

private:
    visitors::spatial_query_incremental<MembersHolder, Predicates> m_impl;
};

template <typename MembersHolder, typename Predicates>
class distance_query_iterator
{
    typedef typename MembersHolder::allocators_type allocators_type;

public:
    typedef std::forward_iterator_tag iterator_category;
    typedef typename MembersHolder::value_type value_type;
    typedef typename allocators_type::const_reference reference;
    typedef typename allocators_type::difference_type difference_type;
    typedef typename allocators_type::const_pointer pointer;

    distance_query_iterator() = default;

    explicit distance_query_iterator(Predicates const& pred)
        : m_impl(pred)
    {}

    distance_query_iterator(MembersHolder const& members, Predicates const& pred)
        : m_impl(members, pred)
    {
        m_impl.initialize(members);
    }

    reference operator*() const
    {
        return m_impl.dereference();
    }

    const value_type * operator->() const
    {
        return boost::addressof(m_impl.dereference());
    }

    distance_query_iterator & operator++()
    {
        m_impl.increment();
        return *this;
    }

    distance_query_iterator operator++(int)
    {
        distance_query_iterator temp = *this;
        this->operator++();
        return temp;
    }

    friend bool operator==(distance_query_iterator const& l, distance_query_iterator const& r)
    {
        return l.m_impl == r.m_impl;
    }

    friend bool operator==(distance_query_iterator const& l, end_query_iterator<value_type, allocators_type> const& /*r*/)
    {
        return l.m_impl.is_end();
    }

    friend bool operator==(end_query_iterator<value_type, allocators_type> const& /*l*/, distance_query_iterator const& r)
    {
        return r.m_impl.is_end();
    }

private:
    visitors::distance_query_incremental<MembersHolder, Predicates> m_impl;
};


template <typename L, typename R>
inline bool operator!=(L const& l, R const& r)
{
    return !(l == r);
}


template <typename Value, typename Allocators>
class query_iterator_base
{
public:
    typedef std::forward_iterator_tag iterator_category;
    typedef Value value_type;
    typedef typename Allocators::const_reference reference;
    typedef typename Allocators::difference_type difference_type;
    typedef typename Allocators::const_pointer pointer;

    virtual ~query_iterator_base() {}

    virtual query_iterator_base * clone() const = 0;

    virtual bool is_end() const = 0;
    virtual reference dereference() const = 0;
    virtual void increment() = 0;
    virtual bool equals(query_iterator_base const&) const = 0;
};

template <typename Value, typename Allocators, typename Iterator>
class query_iterator_wrapper
    : public query_iterator_base<Value, Allocators>
{
    typedef query_iterator_base<Value, Allocators> base_t;

public:
    typedef std::forward_iterator_tag iterator_category;
    typedef Value value_type;
    typedef typename Allocators::const_reference reference;
    typedef typename Allocators::difference_type difference_type;
    typedef typename Allocators::const_pointer pointer;

    query_iterator_wrapper() : m_iterator() {}
    explicit query_iterator_wrapper(Iterator const& it) : m_iterator(it) {}

    virtual base_t * clone() const { return new query_iterator_wrapper(m_iterator); }

    virtual bool is_end() const { return m_iterator == end_query_iterator<Value, Allocators>(); }
    virtual reference dereference() const { return *m_iterator; }
    virtual void increment() { ++m_iterator; }
    virtual bool equals(base_t const& r) const
    {
        const query_iterator_wrapper * p = dynamic_cast<const query_iterator_wrapper *>(boost::addressof(r));
        BOOST_GEOMETRY_INDEX_ASSERT(p, "iterators can't be compared");
        return m_iterator == p->m_iterator;
    }

private:
    Iterator m_iterator;
};


template <typename Value, typename Allocators>
class query_iterator
{
    typedef query_iterator_base<Value, Allocators> iterator_base;
    typedef std::unique_ptr<iterator_base> iterator_ptr;

public:
    typedef std::forward_iterator_tag iterator_category;
    typedef Value value_type;
    typedef typename Allocators::const_reference reference;
    typedef typename Allocators::difference_type difference_type;
    typedef typename Allocators::const_pointer pointer;

    query_iterator() = default;

    template <typename It>
    query_iterator(It const& it)
        : m_ptr(static_cast<iterator_base*>(
                    new query_iterator_wrapper<Value, Allocators, It>(it) ))
    {}

    query_iterator(end_query_iterator<Value, Allocators> const& /*it*/)
    {}

    query_iterator(query_iterator const& o)
        : m_ptr(o.m_ptr.get() ? o.m_ptr->clone() : 0)
    {}

    query_iterator(query_iterator&&) = default;

    query_iterator & operator=(query_iterator const& o)
    {
        if ( this != boost::addressof(o) )
        {
            m_ptr.reset(o.m_ptr.get() ? o.m_ptr->clone() : 0);
        }
        return *this;
    }

    query_iterator& operator=(query_iterator &&) = default;

    reference operator*() const
    {
        return m_ptr->dereference();
    }

    const value_type * operator->() const
    {
        return boost::addressof(m_ptr->dereference());
    }

    query_iterator & operator++()
    {
        m_ptr->increment();
        return *this;
    }

    query_iterator operator++(int)
    {
        query_iterator temp = *this;
        this->operator++();
        return temp;
    }

    friend bool operator==(query_iterator const& l, query_iterator const& r)
    {
        if ( l.m_ptr.get() )
        {
            if ( r.m_ptr.get() )
                return l.m_ptr->equals(*r.m_ptr);
            else
                return l.m_ptr->is_end();
        }
        else
        {
            if ( r.m_ptr.get() )
                return r.m_ptr->is_end();
            else
                return true;
        }
    }

private:
    iterator_ptr m_ptr;
};

}}}}}} // namespace boost::geometry::index::detail::rtree::iterators

#endif // BOOST_GEOMETRY_INDEX_DETAIL_RTREE_QUERY_ITERATORS_HPP