// (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_DETAIL_INDEX_HPP
#define BOOST_GRAPH_DETAIL_INDEX_HPP

#include <boost/graph/graph_traits.hpp>

// The structures in this module are responsible for selecting and defining
// types for accessing a builting index map. Note that the selection of these
// types requires the Graph parameter to model either VertexIndexGraph or
// EdgeIndexGraph.

namespace boost
{
    namespace detail
    {
        template <typename Graph>
        struct vertex_indexer
        {
            typedef vertex_index_t index_type;
            typedef typename property_map<Graph, vertex_index_t>::type map_type;
            typedef typename property_map<Graph, vertex_index_t>::const_type const_map_type;
            typedef typename property_traits<map_type>::value_type value_type;
            typedef typename graph_traits<Graph>::vertex_descriptor key_type;

            static const_map_type index_map(const Graph& g)
            { return get(vertex_index, g); }

            static map_type index_map(Graph& g)
            { return get(vertex_index, g); }

            static value_type index(key_type k, const Graph& g)
            { return get(vertex_index, g, k); }
        };

        template <typename Graph>
        struct edge_indexer
        {
            typedef edge_index_t index_type;
            typedef typename property_map<Graph, edge_index_t>::type map_type;
            typedef typename property_map<Graph, edge_index_t>::const_type const_map_type;
            typedef typename property_traits<map_type>::value_type value_type;
            typedef typename graph_traits<Graph>::edge_descriptor key_type;

            static const_map_type index_map(const Graph& g)
            { return get(edge_index, g); }

            static map_type index_map(Graph& g)
            { return get(edge_index, g); }

            static value_type index(key_type k, const Graph& g)
            { return get(edge_index, g, k); }
        };

        // NOTE: The Graph parameter MUST be a model of VertexIndexGraph or
        // VertexEdgeGraph - whichever type Key is selecting.
        template <typename Graph, typename Key>
        struct choose_indexer
        {
            typedef typename mpl::if_<
                    is_same<Key, typename graph_traits<Graph>::vertex_descriptor>,
                    vertex_indexer<Graph>,
                    edge_indexer<Graph>
                >::type indexer_type;
            typedef typename indexer_type::index_type index_type;
        };
    }
}

#endif