// Boost.Geometry (aka GGL, Generic Geometry Library)

// Copyright (c) 2014-2015, Oracle and/or its affiliates.

// Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle

// Licensed under the Boost Software License version 1.0.
// http://www.boost.org/users/license.html

#ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_HAS_SPIKES_HPP
#define BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_HAS_SPIKES_HPP

#include <algorithm>

#include <boost/core/ignore_unused.hpp>
#include <boost/range.hpp>
#include <boost/type_traits/is_same.hpp>

#include <boost/geometry/core/assert.hpp>
#include <boost/geometry/core/point_type.hpp>
#include <boost/geometry/core/tag.hpp>
#include <boost/geometry/core/tags.hpp>

#include <boost/geometry/policies/is_valid/default_policy.hpp>

#include <boost/geometry/util/range.hpp>

#include <boost/geometry/views/closeable_view.hpp>

#include <boost/geometry/algorithms/equals.hpp>
#include <boost/geometry/algorithms/validity_failure_type.hpp>
#include <boost/geometry/algorithms/detail/point_is_spike_or_equal.hpp>
#include <boost/geometry/io/dsv/write.hpp>


namespace boost { namespace geometry
{


#ifndef DOXYGEN_NO_DETAIL
namespace detail { namespace is_valid
{

template <typename Point>
struct equal_to
{
    Point const& m_point;

    equal_to(Point const& point)
        : m_point(point)
    {}

    template <typename OtherPoint>
    inline bool operator()(OtherPoint const& other) const
    {
        return geometry::equals(m_point, other);
    }
};

template <typename Point>
struct not_equal_to
{
    Point const& m_point;

    not_equal_to(Point const& point)
        : m_point(point)
    {}

    template <typename OtherPoint>
    inline bool operator()(OtherPoint const& other) const
    {
        return ! geometry::equals(other, m_point);
    }
};



template <typename Range, closure_selector Closure>
struct has_spikes
{
    template <typename Iterator>
    static inline Iterator find_different_from_first(Iterator first,
                                                     Iterator last)
    {
        typedef not_equal_to<typename point_type<Range>::type> not_equal;

        BOOST_GEOMETRY_ASSERT(first != last);

        Iterator second = first;
        ++second;
        return std::find_if(second, last, not_equal(*first));
    }

    template <typename VisitPolicy>
    static inline bool apply(Range const& range, VisitPolicy& visitor)
    {
        boost::ignore_unused(visitor);

        typedef typename closeable_view<Range const, Closure>::type view_type;
        typedef typename boost::range_iterator<view_type const>::type iterator; 

        bool const is_linear
            = boost::is_same<typename tag<Range>::type, linestring_tag>::value;

        view_type const view(range);

        iterator prev = boost::begin(view);

        iterator cur = find_different_from_first(prev, boost::end(view));
        if (cur == boost::end(view))
        {
            // the range has only one distinct point, so it
            // cannot have a spike
            return ! visitor.template apply<no_failure>();
        }

        iterator next = find_different_from_first(cur, boost::end(view));
        if (next == boost::end(view))
        {
            // the range has only two distinct points, so it
            // cannot have a spike
            return ! visitor.template apply<no_failure>();
        }

        while (next != boost::end(view))
        {
            if ( geometry::detail::point_is_spike_or_equal(*prev,
                                                           *next,
                                                           *cur) )
            {
                return
                    ! visitor.template apply<failure_spikes>(is_linear, *cur);
            }
            prev = cur;
            cur = next;
            next = find_different_from_first(cur, boost::end(view));
        }

        if (geometry::equals(range::front(view), range::back(view)))
        {
            iterator cur = boost::begin(view);
            typename boost::range_reverse_iterator
                <
                    view_type const
                >::type prev = find_different_from_first(boost::rbegin(view),
                                                         boost::rend(view));

            iterator next = find_different_from_first(cur, boost::end(view));
            if (detail::point_is_spike_or_equal(*prev, *next, *cur))
            {
                return
                    ! visitor.template apply<failure_spikes>(is_linear, *cur);
            }
            else
            {
                return ! visitor.template apply<no_failure>();
            }
        }

        return ! visitor.template apply<no_failure>();
    }
};



}} // namespace detail::is_valid
#endif // DOXYGEN_NO_DETAIL


}} // namespace boost::geometry


#endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_HAS_SPIKES_HPP
