//=======================================================================
// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
//
// Distributed under 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_FILTERED_GRAPH_HPP
#define BOOST_FILTERED_GRAPH_HPP

#include <boost/graph/graph_traits.hpp>
#include <boost/graph/properties.hpp>
#include <boost/graph/adjacency_iterator.hpp>
#include <boost/graph/detail/set_adaptor.hpp>
#include <boost/iterator/filter_iterator.hpp>

namespace boost
{

//=========================================================================
// Some predicate classes.

struct keep_all
{
    template < typename T > bool operator()(const T&) const { return true; }
};

// Keep residual edges (used in maximum-flow algorithms).
template < typename ResidualCapacityEdgeMap > struct is_residual_edge
{
    is_residual_edge() {}
    is_residual_edge(ResidualCapacityEdgeMap rcap) : m_rcap(rcap) {}
    template < typename Edge > bool operator()(const Edge& e) const
    {
        return 0 < get(m_rcap, e);
    }
    ResidualCapacityEdgeMap m_rcap;
};

template < typename Set > struct is_in_subset
{
    is_in_subset() : m_s(0) {}
    is_in_subset(const Set& s) : m_s(&s) {}

    template < typename Elt > bool operator()(const Elt& x) const
    {
        return set_contains(*m_s, x);
    }
    const Set* m_s;
};

template < typename Set > struct is_not_in_subset
{
    is_not_in_subset() : m_s(0) {}
    is_not_in_subset(const Set& s) : m_s(&s) {}

    template < typename Elt > bool operator()(const Elt& x) const
    {
        return !set_contains(*m_s, x);
    }
    const Set* m_s;
};

namespace detail
{

    template < typename EdgePredicate, typename VertexPredicate,
        typename Graph >
    struct out_edge_predicate
    {
        out_edge_predicate() {}
        out_edge_predicate(EdgePredicate ep, VertexPredicate vp, const Graph& g)
        : m_edge_pred(ep), m_vertex_pred(vp), m_g(&g)
        {
        }

        template < typename Edge > bool operator()(const Edge& e) const
        {
            return m_edge_pred(e) && m_vertex_pred(target(e, *m_g));
        }
        EdgePredicate m_edge_pred;
        VertexPredicate m_vertex_pred;
        const Graph* m_g;
    };

    template < typename EdgePredicate, typename VertexPredicate,
        typename Graph >
    struct in_edge_predicate
    {
        in_edge_predicate() {}
        in_edge_predicate(EdgePredicate ep, VertexPredicate vp, const Graph& g)
        : m_edge_pred(ep), m_vertex_pred(vp), m_g(&g)
        {
        }

        template < typename Edge > bool operator()(const Edge& e) const
        {
            return m_edge_pred(e) && m_vertex_pred(source(e, *m_g));
        }
        EdgePredicate m_edge_pred;
        VertexPredicate m_vertex_pred;
        const Graph* m_g;
    };

    template < typename EdgePredicate, typename VertexPredicate,
        typename Graph >
    struct edge_predicate
    {
        edge_predicate() {}
        edge_predicate(EdgePredicate ep, VertexPredicate vp, const Graph& g)
        : m_edge_pred(ep), m_vertex_pred(vp), m_g(&g)
        {
        }

        template < typename Edge > bool operator()(const Edge& e) const
        {
            return m_edge_pred(e) && m_vertex_pred(source(e, *m_g))
                && m_vertex_pred(target(e, *m_g));
        }
        EdgePredicate m_edge_pred;
        VertexPredicate m_vertex_pred;
        const Graph* m_g;
    };

} // namespace detail

//===========================================================================
// Filtered Graph

struct filtered_graph_tag
{
};

// This base class is a stupid hack to change overload resolution
// rules for the source and target functions so that they are a
// worse match than the source and target functions defined for
// pairs in graph_traits.hpp. I feel dirty. -JGS
template < class G > struct filtered_graph_base
{
    typedef graph_traits< G > Traits;
    typedef typename Traits::vertex_descriptor vertex_descriptor;
    typedef typename Traits::edge_descriptor edge_descriptor;
    filtered_graph_base(const G& g) : m_g(g) {}
    // protected:
    const G& m_g;
};

template < typename Graph, typename EdgePredicate,
    typename VertexPredicate = keep_all >
class filtered_graph : public filtered_graph_base< Graph >
{
    typedef filtered_graph_base< Graph > Base;
    typedef graph_traits< Graph > Traits;
    typedef filtered_graph self;

public:
    typedef Graph graph_type;
    typedef detail::out_edge_predicate< EdgePredicate, VertexPredicate, self >
        OutEdgePred;
    typedef detail::in_edge_predicate< EdgePredicate, VertexPredicate, self >
        InEdgePred;
    typedef detail::edge_predicate< EdgePredicate, VertexPredicate, self >
        EdgePred;

    // Constructors
    filtered_graph(const Graph& g, EdgePredicate ep) : Base(g), m_edge_pred(ep)
    {
    }

    filtered_graph(const Graph& g, EdgePredicate ep, VertexPredicate vp)
    : Base(g), m_edge_pred(ep), m_vertex_pred(vp)
    {
    }

    // Graph requirements
    typedef typename Traits::vertex_descriptor vertex_descriptor;
    typedef typename Traits::edge_descriptor edge_descriptor;
    typedef typename Traits::directed_category directed_category;
    typedef typename Traits::edge_parallel_category edge_parallel_category;
    typedef typename Traits::traversal_category traversal_category;

    // IncidenceGraph requirements
    typedef filter_iterator< OutEdgePred, typename Traits::out_edge_iterator >
        out_edge_iterator;

    typedef typename Traits::degree_size_type degree_size_type;

    // AdjacencyGraph requirements
    typedef typename adjacency_iterator_generator< self, vertex_descriptor,
        out_edge_iterator >::type adjacency_iterator;

    // BidirectionalGraph requirements
    typedef filter_iterator< InEdgePred, typename Traits::in_edge_iterator >
        in_edge_iterator;

    // VertexListGraph requirements
    typedef filter_iterator< VertexPredicate, typename Traits::vertex_iterator >
        vertex_iterator;
    typedef typename Traits::vertices_size_type vertices_size_type;

    // EdgeListGraph requirements
    typedef filter_iterator< EdgePred, typename Traits::edge_iterator >
        edge_iterator;
    typedef typename Traits::edges_size_type edges_size_type;

    typedef filtered_graph_tag graph_tag;

    // Bundled properties support
    template < typename Descriptor >
    typename graph::detail::bundled_result< Graph, Descriptor >::type&
    operator[](Descriptor x)
    {
        return const_cast< Graph& >(this->m_g)[x];
    }

    template < typename Descriptor >
    typename graph::detail::bundled_result< Graph, Descriptor >::type const&
    operator[](Descriptor x) const
    {
        return this->m_g[x];
    }

    static vertex_descriptor null_vertex() { return Traits::null_vertex(); }

    // private:
    EdgePredicate m_edge_pred;
    VertexPredicate m_vertex_pred;
};

// Do not instantiate these unless needed
template < typename Graph, typename EdgePredicate, typename VertexPredicate >
struct vertex_property_type<
    filtered_graph< Graph, EdgePredicate, VertexPredicate > >
: vertex_property_type< Graph >
{
};

template < typename Graph, typename EdgePredicate, typename VertexPredicate >
struct edge_property_type<
    filtered_graph< Graph, EdgePredicate, VertexPredicate > >
: edge_property_type< Graph >
{
};

template < typename Graph, typename EdgePredicate, typename VertexPredicate >
struct graph_property_type<
    filtered_graph< Graph, EdgePredicate, VertexPredicate > >
: graph_property_type< Graph >
{
};

template < typename Graph, typename EdgePredicate, typename VertexPredicate >
struct vertex_bundle_type<
    filtered_graph< Graph, EdgePredicate, VertexPredicate > >
: vertex_bundle_type< Graph >
{
};

template < typename Graph, typename EdgePredicate, typename VertexPredicate >
struct edge_bundle_type<
    filtered_graph< Graph, EdgePredicate, VertexPredicate > >
: edge_bundle_type< Graph >
{
};

template < typename Graph, typename EdgePredicate, typename VertexPredicate >
struct graph_bundle_type<
    filtered_graph< Graph, EdgePredicate, VertexPredicate > >
: graph_bundle_type< Graph >
{
};

//===========================================================================
// Non-member functions for the Filtered Edge Graph

// Helper functions
template < typename Graph, typename EdgePredicate >
inline filtered_graph< Graph, EdgePredicate > make_filtered_graph(
    Graph& g, EdgePredicate ep)
{
    return filtered_graph< Graph, EdgePredicate >(g, ep);
}
template < typename Graph, typename EdgePredicate, typename VertexPredicate >
inline filtered_graph< Graph, EdgePredicate, VertexPredicate >
make_filtered_graph(Graph& g, EdgePredicate ep, VertexPredicate vp)
{
    return filtered_graph< Graph, EdgePredicate, VertexPredicate >(g, ep, vp);
}

template < typename Graph, typename EdgePredicate >
inline filtered_graph< const Graph, EdgePredicate > make_filtered_graph(
    const Graph& g, EdgePredicate ep)
{
    return filtered_graph< const Graph, EdgePredicate >(g, ep);
}
template < typename Graph, typename EdgePredicate, typename VertexPredicate >
inline filtered_graph< const Graph, EdgePredicate, VertexPredicate >
make_filtered_graph(const Graph& g, EdgePredicate ep, VertexPredicate vp)
{
    return filtered_graph< const Graph, EdgePredicate, VertexPredicate >(
        g, ep, vp);
}

template < typename G, typename EP, typename VP >
std::pair< typename filtered_graph< G, EP, VP >::vertex_iterator,
    typename filtered_graph< G, EP, VP >::vertex_iterator >
vertices(const filtered_graph< G, EP, VP >& g)
{
    typedef filtered_graph< G, EP, VP > Graph;
    typename graph_traits< G >::vertex_iterator f, l;
    boost::tie(f, l) = vertices(g.m_g);
    typedef typename Graph::vertex_iterator iter;
    return std::make_pair(
        iter(g.m_vertex_pred, f, l), iter(g.m_vertex_pred, l, l));
}

template < typename G, typename EP, typename VP >
std::pair< typename filtered_graph< G, EP, VP >::edge_iterator,
    typename filtered_graph< G, EP, VP >::edge_iterator >
edges(const filtered_graph< G, EP, VP >& g)
{
    typedef filtered_graph< G, EP, VP > Graph;
    typename Graph::EdgePred pred(g.m_edge_pred, g.m_vertex_pred, g);
    typename graph_traits< G >::edge_iterator f, l;
    boost::tie(f, l) = edges(g.m_g);
    typedef typename Graph::edge_iterator iter;
    return std::make_pair(iter(pred, f, l), iter(pred, l, l));
}

// An alternative for num_vertices() and num_edges() would be to
// count the number in the filtered graph. This is problematic
// because of the interaction with the vertex indices...  they would
// no longer go from 0 to num_vertices(), which would cause trouble
// for algorithms allocating property storage in an array. We could
// try to create a mapping to new recalibrated indices, but I don't
// see an efficient way to do this.
//
// However, the current solution is still unsatisfactory because
// the following semantic constraints no longer hold:
// boost::tie(vi, viend) = vertices(g);
// assert(std::distance(vi, viend) == num_vertices(g));

template < typename G, typename EP, typename VP >
typename filtered_graph< G, EP, VP >::vertices_size_type num_vertices(
    const filtered_graph< G, EP, VP >& g)
{
    return num_vertices(g.m_g);
}

template < typename G, typename EP, typename VP >
typename filtered_graph< G, EP, VP >::edges_size_type num_edges(
    const filtered_graph< G, EP, VP >& g)
{
    return num_edges(g.m_g);
}

template < typename G >
typename filtered_graph_base< G >::vertex_descriptor source(
    typename filtered_graph_base< G >::edge_descriptor e,
    const filtered_graph_base< G >& g)
{
    return source(e, g.m_g);
}

template < typename G >
typename filtered_graph_base< G >::vertex_descriptor target(
    typename filtered_graph_base< G >::edge_descriptor e,
    const filtered_graph_base< G >& g)
{
    return target(e, g.m_g);
}

template < typename G, typename EP, typename VP >
std::pair< typename filtered_graph< G, EP, VP >::out_edge_iterator,
    typename filtered_graph< G, EP, VP >::out_edge_iterator >
out_edges(typename filtered_graph< G, EP, VP >::vertex_descriptor u,
    const filtered_graph< G, EP, VP >& g)
{
    typedef filtered_graph< G, EP, VP > Graph;
    typename Graph::OutEdgePred pred(g.m_edge_pred, g.m_vertex_pred, g);
    typedef typename Graph::out_edge_iterator iter;
    typename graph_traits< G >::out_edge_iterator f, l;
    boost::tie(f, l) = out_edges(u, g.m_g);
    return std::make_pair(iter(pred, f, l), iter(pred, l, l));
}

template < typename G, typename EP, typename VP >
typename filtered_graph< G, EP, VP >::degree_size_type out_degree(
    typename filtered_graph< G, EP, VP >::vertex_descriptor u,
    const filtered_graph< G, EP, VP >& g)
{
    typename filtered_graph< G, EP, VP >::degree_size_type n = 0;
    typename filtered_graph< G, EP, VP >::out_edge_iterator f, l;
    for (boost::tie(f, l) = out_edges(u, g); f != l; ++f)
        ++n;
    return n;
}

template < typename G, typename EP, typename VP >
std::pair< typename filtered_graph< G, EP, VP >::adjacency_iterator,
    typename filtered_graph< G, EP, VP >::adjacency_iterator >
adjacent_vertices(typename filtered_graph< G, EP, VP >::vertex_descriptor u,
    const filtered_graph< G, EP, VP >& g)
{
    typedef filtered_graph< G, EP, VP > Graph;
    typedef typename Graph::adjacency_iterator adjacency_iterator;
    typename Graph::out_edge_iterator f, l;
    boost::tie(f, l) = out_edges(u, g);
    return std::make_pair(adjacency_iterator(f, const_cast< Graph* >(&g)),
        adjacency_iterator(l, const_cast< Graph* >(&g)));
}

template < typename G, typename EP, typename VP >
std::pair< typename filtered_graph< G, EP, VP >::in_edge_iterator,
    typename filtered_graph< G, EP, VP >::in_edge_iterator >
in_edges(typename filtered_graph< G, EP, VP >::vertex_descriptor u,
    const filtered_graph< G, EP, VP >& g)
{
    typedef filtered_graph< G, EP, VP > Graph;
    typename Graph::InEdgePred pred(g.m_edge_pred, g.m_vertex_pred, g);
    typedef typename Graph::in_edge_iterator iter;
    typename graph_traits< G >::in_edge_iterator f, l;
    boost::tie(f, l) = in_edges(u, g.m_g);
    return std::make_pair(iter(pred, f, l), iter(pred, l, l));
}

template < typename G, typename EP, typename VP >
typename filtered_graph< G, EP, VP >::degree_size_type in_degree(
    typename filtered_graph< G, EP, VP >::vertex_descriptor u,
    const filtered_graph< G, EP, VP >& g)
{
    typename filtered_graph< G, EP, VP >::degree_size_type n = 0;
    typename filtered_graph< G, EP, VP >::in_edge_iterator f, l;
    for (boost::tie(f, l) = in_edges(u, g); f != l; ++f)
        ++n;
    return n;
}

template < typename G, typename EP, typename VP >
typename enable_if< typename is_directed_graph< G >::type,
    typename filtered_graph< G, EP, VP >::degree_size_type >::type
degree(typename filtered_graph< G, EP, VP >::vertex_descriptor u,
    const filtered_graph< G, EP, VP >& g)
{
    return out_degree(u, g) + in_degree(u, g);
}

template < typename G, typename EP, typename VP >
typename disable_if< typename is_directed_graph< G >::type,
    typename filtered_graph< G, EP, VP >::degree_size_type >::type
degree(typename filtered_graph< G, EP, VP >::vertex_descriptor u,
    const filtered_graph< G, EP, VP >& g)
{
    return out_degree(u, g);
}

template < typename G, typename EP, typename VP >
std::pair< typename filtered_graph< G, EP, VP >::edge_descriptor, bool > edge(
    typename filtered_graph< G, EP, VP >::vertex_descriptor u,
    typename filtered_graph< G, EP, VP >::vertex_descriptor v,
    const filtered_graph< G, EP, VP >& g)
{
    typename graph_traits< G >::edge_descriptor e;
    bool exists;
    boost::tie(e, exists) = edge(u, v, g.m_g);
    return std::make_pair(e, exists && g.m_edge_pred(e));
}

template < typename G, typename EP, typename VP >
std::pair< typename filtered_graph< G, EP, VP >::out_edge_iterator,
    typename filtered_graph< G, EP, VP >::out_edge_iterator >
edge_range(typename filtered_graph< G, EP, VP >::vertex_descriptor u,
    typename filtered_graph< G, EP, VP >::vertex_descriptor v,
    const filtered_graph< G, EP, VP >& g)
{
    typedef filtered_graph< G, EP, VP > Graph;
    typename Graph::OutEdgePred pred(g.m_edge_pred, g.m_vertex_pred, g);
    typedef typename Graph::out_edge_iterator iter;
    typename graph_traits< G >::out_edge_iterator f, l;
    boost::tie(f, l) = edge_range(u, v, g.m_g);
    return std::make_pair(iter(pred, f, l), iter(pred, l, l));
}

//===========================================================================
// Property map

template < typename G, typename EP, typename VP, typename Property >
struct property_map< filtered_graph< G, EP, VP >, Property >
: property_map< G, Property >
{
};

template < typename G, typename EP, typename VP, typename Property >
typename property_map< G, Property >::type get(
    Property p, filtered_graph< G, EP, VP >& g)
{
    return get(p, const_cast< G& >(g.m_g));
}

template < typename G, typename EP, typename VP, typename Property >
typename property_map< G, Property >::const_type get(
    Property p, const filtered_graph< G, EP, VP >& g)
{
    return get(p, (const G&)g.m_g);
}

template < typename G, typename EP, typename VP, typename Property,
    typename Key >
typename property_map_value< G, Property >::type get(
    Property p, const filtered_graph< G, EP, VP >& g, const Key& k)
{
    return get(p, (const G&)g.m_g, k);
}

template < typename G, typename EP, typename VP, typename Property,
    typename Key, typename Value >
void put(Property p, const filtered_graph< G, EP, VP >& g, const Key& k,
    const Value& val)
{
    put(p, const_cast< G& >(g.m_g), k, val);
}

//===========================================================================
// Some filtered subgraph specializations

template < typename Graph, typename Set > struct vertex_subset_filter
{
    typedef filtered_graph< Graph, keep_all, is_in_subset< Set > > type;
};
template < typename Graph, typename Set >
inline typename vertex_subset_filter< Graph, Set >::type
make_vertex_subset_filter(Graph& g, const Set& s)
{
    typedef typename vertex_subset_filter< Graph, Set >::type Filter;
    is_in_subset< Set > p(s);
    return Filter(g, keep_all(), p);
}

// This is misspelled, but present for backwards compatibility; new code
// should use the version below that has the correct spelling.
template < typename Graph, typename Set > struct vertex_subset_compliment_filter
{
    typedef filtered_graph< Graph, keep_all, is_not_in_subset< Set > > type;
};
template < typename Graph, typename Set >
inline typename vertex_subset_compliment_filter< Graph, Set >::type
make_vertex_subset_compliment_filter(Graph& g, const Set& s)
{
    typedef typename vertex_subset_compliment_filter< Graph, Set >::type Filter;
    is_not_in_subset< Set > p(s);
    return Filter(g, keep_all(), p);
}

template < typename Graph, typename Set > struct vertex_subset_complement_filter
{
    typedef filtered_graph< Graph, keep_all, is_not_in_subset< Set > > type;
};
template < typename Graph, typename Set >
inline typename vertex_subset_complement_filter< Graph, Set >::type
make_vertex_subset_complement_filter(Graph& g, const Set& s)
{
    typedef typename vertex_subset_complement_filter< Graph, Set >::type Filter;
    is_not_in_subset< Set > p(s);
    return Filter(g, keep_all(), p);
}

// Filter that uses a property map whose value_type is a boolean
template < typename PropertyMap > struct property_map_filter
{

    property_map_filter() {}

    property_map_filter(const PropertyMap& property_map)
    : m_property_map(property_map)
    {
    }

    template < typename Key > bool operator()(const Key& key) const
    {
        return (get(m_property_map, key));
    }

private:
    PropertyMap m_property_map;
};

} // namespace boost

#endif // BOOST_FILTERED_GRAPH_HPP