//

//=======================================================================

// 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_GRAPH_UNDIRECTED_DFS_HPP

#define BOOST_GRAPH_UNDIRECTED_DFS_HPP

#include <boost/graph/depth_first_search.hpp>

#include <vector>

namespace boost {

  namespace detail {

// Define BOOST_RECURSIVE_DFS to use older, recursive version.

// It is retained for a while in order to perform performance

// comparison.

#ifndef BOOST_RECURSIVE_DFS

    template <typename IncidenceGraph, typename DFSVisitor, 

              typename VertexColorMap, typename EdgeColorMap>

    void undir_dfv_impl

      (const IncidenceGraph& g,

       typename graph_traits<IncidenceGraph>::vertex_descriptor u, 

       DFSVisitor& vis,

       VertexColorMap vertex_color,

       EdgeColorMap edge_color)

    {

      function_requires<IncidenceGraphConcept<IncidenceGraph> >();

      function_requires<DFSVisitorConcept<DFSVisitor, IncidenceGraph> >();

      typedef typename graph_traits<IncidenceGraph>::vertex_descriptor Vertex;

      typedef typename graph_traits<IncidenceGraph>::edge_descriptor Edge;

      function_requires<ReadWritePropertyMapConcept<VertexColorMap,Vertex> >();

      function_requires<ReadWritePropertyMapConcept<EdgeColorMap,Edge> >();

      typedef typename property_traits<VertexColorMap>::value_type ColorValue;

      typedef typename property_traits<EdgeColorMap>::value_type EColorValue;

      function_requires< ColorValueConcept<ColorValue> >();

      function_requires< ColorValueConcept<EColorValue> >();

      typedef color_traits<ColorValue> Color;

      typedef color_traits<EColorValue> EColor;

      typedef typename graph_traits<IncidenceGraph>::out_edge_iterator Iter;

      typedef std::pair<Vertex, std::pair<Iter, Iter> > VertexInfo;

      std::vector<VertexInfo> stack;

      put(vertex_color, u, Color::gray());

      vis.discover_vertex(u, g);

      stack.push_back(std::make_pair(u, out_edges(u, g)));

      while (!stack.empty()) {

        VertexInfo& back = stack.back();

        u = back.first;

        Iter ei, ei_end;

        tie(ei, ei_end) = back.second;

        stack.pop_back();

        while (ei != ei_end) {

          Vertex v = target(*ei, g);

          vis.examine_edge(*ei, g);

          ColorValue v_color = get(vertex_color, v);

          EColorValue uv_color = get(edge_color, *ei);

          put(edge_color, *ei, EColor::black());

          if (v_color == Color::white()) {

            vis.tree_edge(*ei, g);

            stack.push_back(std::make_pair(u, std::make_pair(++ei, ei_end)));

            u = v;

            put(vertex_color, u, Color::gray());

            vis.discover_vertex(u, g);

            tie(ei, ei_end) = out_edges(u, g);

          } else if (v_color == Color::gray()) {

            if (uv_color == EColor::white()) vis.back_edge(*ei, g);

            ++ei;

          } else { // if (v_color == Color::black())

            ++ei;

          }

        }

        put(vertex_color, u, Color::black());

        vis.finish_vertex(u, g);

      }

    }

#else // BOOST_RECURSIVE_DFS

    template <typename IncidenceGraph, typename DFSVisitor, 

              typename VertexColorMap, typename EdgeColorMap>

    void undir_dfv_impl

      (const IncidenceGraph& g,

       typename graph_traits<IncidenceGraph>::vertex_descriptor u, 

       DFSVisitor& vis,  // pass-by-reference here, important!

       VertexColorMap vertex_color,

       EdgeColorMap edge_color)

    {

      function_requires<IncidenceGraphConcept<IncidenceGraph> >();

      function_requires<DFSVisitorConcept<DFSVisitor, IncidenceGraph> >();

      typedef typename graph_traits<IncidenceGraph>::vertex_descriptor Vertex;

      typedef typename graph_traits<IncidenceGraph>::edge_descriptor Edge;

      function_requires<ReadWritePropertyMapConcept<VertexColorMap,Vertex> >();

      function_requires<ReadWritePropertyMapConcept<EdgeColorMap,Edge> >();

      typedef typename property_traits<VertexColorMap>::value_type ColorValue;

      typedef typename property_traits<EdgeColorMap>::value_type EColorValue;

      function_requires< ColorValueConcept<ColorValue> >();

      function_requires< ColorValueConcept<EColorValue> >();

      typedef color_traits<ColorValue> Color;

      typedef color_traits<EColorValue> EColor;

      typename graph_traits<IncidenceGraph>::out_edge_iterator ei, ei_end;

      put(vertex_color, u, Color::gray());   vis.discover_vertex(u, g);

      for (tie(ei, ei_end) = out_edges(u, g); ei != ei_end; ++ei) {

        Vertex v = target(*ei, g);           vis.examine_edge(*ei, g);

        ColorValue v_color = get(vertex_color, v);

        EColorValue uv_color = get(edge_color, *ei);

        put(edge_color, *ei, EColor::black());

        if (v_color == Color::white()) {     vis.tree_edge(*ei, g);

          undir_dfv_impl(g, v, vis, vertex_color, edge_color);

        } else if (v_color == Color::gray() && uv_color == EColor::white())

                                             vis.back_edge(*ei, g);

      }

      put(vertex_color, u, Color::black());  vis.finish_vertex(u, g);

    }

#endif // ! BOOST_RECURSIVE_DFS

  } // namespace detail

  template <typename Graph, typename DFSVisitor, 

            typename VertexColorMap, typename EdgeColorMap, 

            typename Vertex>

  void

  undirected_dfs(const Graph& g, DFSVisitor vis, 

                 VertexColorMap vertex_color, EdgeColorMap edge_color,

                 Vertex start_vertex)

  {

    function_requires<DFSVisitorConcept<DFSVisitor, Graph> >();

      function_requires<EdgeListGraphConcept<Graph> >();

    typedef typename property_traits<VertexColorMap>::value_type ColorValue;

    typedef color_traits<ColorValue> Color;

    typename graph_traits<Graph>::vertex_iterator ui, ui_end;

    for (tie(ui, ui_end) = vertices(g); ui != ui_end; ++ui) {

      put(vertex_color, *ui, Color::white());   vis.initialize_vertex(*ui, g);

    }

    typename graph_traits<Graph>::edge_iterator ei, ei_end;

    for (tie(ei, ei_end) = edges(g); ei != ei_end; ++ei)

      put(edge_color, *ei, Color::white());

    if (start_vertex != *vertices(g).first){ vis.start_vertex(start_vertex, g);

      detail::undir_dfv_impl(g, start_vertex, vis, vertex_color, edge_color);

    }

    for (tie(ui, ui_end) = vertices(g); ui != ui_end; ++ui) {

      ColorValue u_color = get(vertex_color, *ui);

      if (u_color == Color::white()) {       vis.start_vertex(*ui, g);

        detail::undir_dfv_impl(g, *ui, vis, vertex_color, edge_color);

      }

    }

  }

  template <typename Graph, typename DFSVisitor, typename VertexColorMap,

    typename EdgeColorMap>

  void

  undirected_dfs(const Graph& g, DFSVisitor vis, 

                 VertexColorMap vertex_color, EdgeColorMap edge_color)

  {

    undirected_dfs(g, vis, vertex_color, edge_color, *vertices(g).first);

  }

  namespace detail {

    template <typename VertexColorMap>

    struct udfs_dispatch {

      template <typename Graph, typename Vertex, 

                typename DFSVisitor, typename EdgeColorMap,

                typename P, typename T, typename R>

      static void

      apply(const Graph& g, DFSVisitor vis, Vertex start_vertex,

            const bgl_named_params<P, T, R>&,

            EdgeColorMap edge_color,

            VertexColorMap vertex_color)

      {

        undirected_dfs(g, vis, vertex_color, edge_color, start_vertex);

      }

    };

    template <>

    struct udfs_dispatch<detail::error_property_not_found> {

      template <typename Graph, typename Vertex, typename DFSVisitor,

                typename EdgeColorMap,

                typename P, typename T, typename R>

      static void

      apply(const Graph& g, DFSVisitor vis, Vertex start_vertex,

            const bgl_named_params<P, T, R>& params,

            EdgeColorMap edge_color,

            detail::error_property_not_found)

      {

        std::vector<default_color_type> color_vec(num_vertices(g));

        default_color_type c = white_color; // avoid warning about un-init

        undirected_dfs

          (g, vis, make_iterator_property_map

           (color_vec.begin(),

            choose_const_pmap(get_param(params, vertex_index),

                              g, vertex_index), c),

           edge_color,

           start_vertex);

      }

    };

  } // namespace detail

  // Named Parameter Variant

  template <typename Graph, typename P, typename T, typename R>

  void

  undirected_dfs(const Graph& g, 

                 const bgl_named_params<P, T, R>& params)

  {

    typedef typename property_value< bgl_named_params<P, T, R>, 

      vertex_color_t>::type C;

    detail::udfs_dispatch<C>::apply

      (g,

       choose_param(get_param(params, graph_visitor),

                    make_dfs_visitor(null_visitor())),

       choose_param(get_param(params, root_vertex_t()),

                    *vertices(g).first),

       params,

       get_param(params, edge_color),

       get_param(params, vertex_color)

       );

  }

  template <typename IncidenceGraph, typename DFSVisitor, 

    typename VertexColorMap, typename EdgeColorMap>

  void undirected_depth_first_visit

    (const IncidenceGraph& g,

     typename graph_traits<IncidenceGraph>::vertex_descriptor u, 

     DFSVisitor vis, VertexColorMap vertex_color, EdgeColorMap edge_color)

  {

    detail::undir_dfv_impl(g, u, vis, vertex_color, edge_color);

  }

} // namespace boost

#endif