// (C) Copyright 2007-2009 Andrew Sutton
//
// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0 (See accompanying file
// LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)

#ifndef BOOST_GRAPH_CLOSENESS_CENTRALITY_HPP
#define BOOST_GRAPH_CLOSENESS_CENTRALITY_HPP

#include <boost/graph/detail/geodesic.hpp>
#include <boost/graph/exterior_property.hpp>

namespace boost
{
template <typename Graph,
          typename DistanceType,
          typename ResultType,
          typename Reciprocal = detail::reciprocal<ResultType> >
struct closeness_measure
    : public geodesic_measure<Graph, DistanceType, ResultType>
{
    typedef geodesic_measure< Graph, DistanceType, ResultType> base_type;
    typedef typename base_type::distance_type distance_type;
    typedef typename base_type::result_type result_type;

    result_type operator ()(distance_type d, const Graph&)
    {
        function_requires< NumericValueConcept<DistanceType> >();
        function_requires< NumericValueConcept<ResultType> >();
        function_requires< AdaptableUnaryFunctionConcept<Reciprocal,ResultType,ResultType> >();
        return (d == base_type::infinite_distance())
            ? base_type::zero_result()
            : rec(result_type(d));
    }
    Reciprocal rec;
};

template <typename Graph, typename DistanceMap>
inline closeness_measure<
        Graph, typename property_traits<DistanceMap>::value_type, double,
        detail::reciprocal<double> >
measure_closeness(const Graph&, DistanceMap)
{
    typedef typename property_traits<DistanceMap>::value_type Distance;
    return closeness_measure<Graph, Distance, double, detail::reciprocal<double> >();
}

template <typename T, typename Graph, typename DistanceMap>
inline closeness_measure<
        Graph, typename property_traits<DistanceMap>::value_type, T,
        detail::reciprocal<T> >
measure_closeness(const Graph&, DistanceMap)
{
    typedef typename property_traits<DistanceMap>::value_type Distance;
    return closeness_measure<Graph, Distance, T, detail::reciprocal<T> >();
}

template <typename T, typename Graph, typename DistanceMap, typename Reciprocal>
inline closeness_measure<
        Graph, typename property_traits<DistanceMap>::value_type, T,
        Reciprocal>
measure_closeness(const Graph&, DistanceMap)
{
    typedef typename property_traits<DistanceMap>::value_type Distance;
    return closeness_measure<Graph, Distance, T, Reciprocal>();
}

template <typename Graph,
          typename DistanceMap,
          typename Measure,
          typename Combinator>
inline typename Measure::result_type
closeness_centrality(const Graph& g,
                     DistanceMap dist,
                     Measure measure,
                     Combinator combine)
{
    function_requires< VertexListGraphConcept<Graph> >();
    typedef typename graph_traits<Graph>::vertex_descriptor Vertex;
    function_requires< ReadablePropertyMapConcept<DistanceMap,Vertex> >();
    typedef typename property_traits<DistanceMap>::value_type Distance;
    function_requires< NumericValueConcept<Distance> >();
    function_requires< DistanceMeasureConcept<Measure,Graph> >();

    Distance n = detail::combine_distances(g, dist, combine, Distance(0));
    return measure(n, g);
}

template <typename Graph, typename DistanceMap, typename Measure>
inline typename Measure::result_type
closeness_centrality(const Graph& g, DistanceMap dist, Measure measure)
{
    function_requires< GraphConcept<Graph> >();
    typedef typename graph_traits<Graph>::vertex_descriptor Vertex;
    function_requires< ReadablePropertyMapConcept<DistanceMap,Vertex> >();
    typedef typename property_traits<DistanceMap>::value_type Distance;

    return closeness_centrality(g, dist, measure, std::plus<Distance>());
}

template <typename Graph, typename DistanceMap>
inline double closeness_centrality(const Graph& g, DistanceMap dist)
{ return closeness_centrality(g, dist, measure_closeness(g, dist)); }

template <typename T, typename Graph, typename DistanceMap>
inline T closeness_centrality(const Graph& g, DistanceMap dist)
{ return closeness_centrality(g, dist, measure_closeness<T>(g, dist)); }

template <typename Graph,
          typename DistanceMatrixMap,
          typename CentralityMap,
          typename Measure>
inline void
all_closeness_centralities(const Graph& g,
                           DistanceMatrixMap dist,
                           CentralityMap cent,
                           Measure measure)
{
    function_requires< VertexListGraphConcept<Graph> >();
    typedef typename graph_traits<Graph>::vertex_descriptor Vertex;
    function_requires< ReadablePropertyMapConcept<DistanceMatrixMap,Vertex> >();
    typedef typename property_traits<DistanceMatrixMap>::value_type DistanceMap;
    function_requires< ReadablePropertyMapConcept<DistanceMap,Vertex> >();
    function_requires< WritablePropertyMapConcept<CentralityMap,Vertex> >();
    typedef typename property_traits<DistanceMap>::value_type Distance;
    typedef typename property_traits<CentralityMap>::value_type Centrality;

    typename graph_traits<Graph>::vertex_iterator i, end;
    for(tie(i, end) = vertices(g); i != end; ++i) {
        DistanceMap dm = get(dist, *i);
        Centrality c = closeness_centrality(g, dm, measure);
        put(cent, *i, c);
    }
}

template <typename Graph,
          typename DistanceMatrixMap,
          typename CentralityMap>
inline void
all_closeness_centralities(const Graph& g,
                            DistanceMatrixMap dist,
                            CentralityMap cent)
{
    function_requires< GraphConcept<Graph> >();
    typedef typename graph_traits<Graph>::vertex_descriptor Vertex;
    function_requires< ReadablePropertyMapConcept<DistanceMatrixMap,Vertex> >();
    typedef typename property_traits<DistanceMatrixMap>::value_type DistanceMap;
    function_requires< ReadablePropertyMapConcept<DistanceMap,Vertex> >();
    typedef typename property_traits<DistanceMap>::value_type Distance;
    typedef typename property_traits<CentralityMap>::value_type Result;

    all_closeness_centralities(g, dist, cent, measure_closeness<Result>(g, DistanceMap()));
}

} /* namespace boost */

#endif