//
//=======================================================================
// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
//
// This file is part of the Boost Graph Library
//
// You should have received a copy of the License Agreement for the
// Boost Graph Library along with the software; see the file LICENSE.
// If not, contact Office of Research, University of Notre Dame, Notre
// Dame, IN 46556.
//
// Permission to modify the code and to distribute modified code is
// granted, provided the text of this NOTICE is retained, a notice that
// the code was modified is included with the above COPYRIGHT NOTICE and
// with the COPYRIGHT NOTICE in the LICENSE file, and that the LICENSE
// file is distributed with the modified code.
//
// LICENSOR MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED.
// By way of example, but not limitation, Licensor MAKES NO
// REPRESENTATIONS OR WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY
// PARTICULAR PURPOSE OR THAT THE USE OF THE LICENSED SOFTWARE COMPONENTS
// OR DOCUMENTATION WILL NOT INFRINGE ANY PATENTS, COPYRIGHTS, TRADEMARKS
// OR OTHER RIGHTS.
//=======================================================================
//
#ifndef BOOST_GRAPH_RECURSIVE_DFS_HPP
#define BOOST_GRAPH_RECURSIVE_DFS_HPP

#include <stack>
#include <boost/config.hpp>
#include <boost/graph/graph_traits.hpp>
#include <boost/graph/graph_concepts.hpp>
#include <boost/graph/properties.hpp>
#include <boost/graph/visitors.hpp>

namespace boost {

  template <class Visitor, class Graph>
  class DFSVisitorConcept {
  public:
    void constraints() {
      vis.initialize_vertex(u, g);
      vis.start_vertex(u, g);
      vis.discover_vertex(u, g);
      vis.examine_edge(e, g);
      vis.tree_edge(e, g);
      vis.back_edge(e, g);
      vis.forward_or_cross_edge(e, g);
      vis.finish_vertex(u, g);
    }
  private:
    Visitor vis;
    Graph g;
    typename graph_traits<Graph>::vertex_descriptor u;
    typename graph_traits<Graph>::edge_descriptor e;
  };

  namespace detail {

    template <class IncidenceGraph, class DFSVisitor, class ColorMap>
    void internal_depth_first_visit
      (const IncidenceGraph& g,
       typename graph_traits<IncidenceGraph>::vertex_descriptor u, 
       DFSVisitor& vis,  // pass-by-reference here, important!
       ColorMap color)
    {
      function_requires<IncidenceGraphConcept<IncidenceGraph> >();
      function_requires<DFSVisitorConcept<DFSVisitor, IncidenceGraph> >();
      typedef typename property_traits<ColorMap>::value_type ColorValue;
      function_requires< ColorValueConcept<ColorValue> >();
      typedef color_traits<ColorValue> Color;

      put(color, u, Color::gray());
      vis.discover_vertex(u, g);
      typename graph_traits<IncidenceGraph>::out_edge_iterator ei, ei_end;
      for (tie(ei, ei_end) = out_edges(u, g); ei != ei_end; ++ei) {
	vis.examine_edge(*ei, g);
	if (get(color, target(*ei, g)) == Color::white()) {
	  vis.tree_edge(*ei, g);
	  internal_depth_first_visit(g, target(*ei, g), vis, color);
	} else if (get(color, target(*ei, g)) == Color::gray())
	  vis.back_edge(*ei, g);
	else
	  vis.forward_or_cross_edge(*ei, g);
      }
      put(color, u, Color::black());
      vis.finish_vertex(u, g);
    }

  }
  
  // Variant (1)
  template <class Graph, class DFSVisitor>
  inline void
  depth_first_search(Graph& g, DFSVisitor v)
  {
    typedef typename graph_traits<Graph>::vertex_descriptor Vertex;
    depth_first_search(g, v, get(vertex_color, g));
  }

  // Variant (2)
  template <class VertexListGraph, class DFSVisitor, class ColorMap>
  void
  depth_first_search(const VertexListGraph& g, DFSVisitor vis, ColorMap color)
  {
    function_requires<DFSVisitorConcept<DFSVisitor, VertexListGraph> >();
    typedef typename property_traits<ColorMap>::value_type ColorValue;
    typedef color_traits<ColorValue> Color;

    typename graph_traits<VertexListGraph>::vertex_iterator ui, ui_end;
    for (tie(ui, ui_end) = vertices(g); ui != ui_end; ++ui) {
      put(color, *ui, Color::white());
      vis.initialize_vertex(*ui, g);
    }
    for (tie(ui, ui_end) = vertices(g); ui != ui_end; ++ui)
      if (get(color, *ui) == Color::white()) {
        vis.start_vertex(*ui, g);
        detail::internal_depth_first_visit(g, *ui, vis, color);
      }
  }

  template <class IncidenceGraph, class DFSVisitor, class ColorMap>
  void depth_first_visit
    (const IncidenceGraph& g,
     typename graph_traits<IncidenceGraph>::vertex_descriptor u, 
     DFSVisitor vis, ColorMap color)
  {
    detail::internal_depth_first_visit(g, u, vis, color);
  }


  template <class Visitors = null_visitor>
  class dfs_visitor {
  public:
    dfs_visitor(Visitors vis = Visitors()) : m_vis(vis) { }

    template <class Vertex, class Graph>
    void initialize_vertex(Vertex u, Graph& g) {
      invoke_visitors(m_vis, u, g, on_initialize_vertex());      
    }
    template <class Vertex, class Graph>
    void start_vertex(Vertex u, Graph& g) {
      invoke_visitors(m_vis, u, g, on_start_vertex());      
    }
    template <class Vertex, class Graph>
    void discover_vertex(Vertex u, Graph& g) {
      invoke_visitors(m_vis, u, g, on_discover_vertex());      
    }
    template <class Edge, class Graph>
    void examine_edge(Edge u, Graph& g) {
      invoke_visitors(m_vis, u, g, on_examine_edge());
    }
    template <class Edge, class Graph>
    void tree_edge(Edge u, Graph& g) {
      invoke_visitors(m_vis, u, g, on_tree_edge());      
    }
    template <class Edge, class Graph>
    void back_edge(Edge u, Graph& g) {
      invoke_visitors(m_vis, u, g, on_back_edge());
    }
    template <class Edge, class Graph>
    void forward_or_cross_edge(Edge u, Graph& g) {
      invoke_visitors(m_vis, u, g, on_forward_or_cross_edge());
    }
    template <class Vertex, class Graph>
    void finish_vertex(Vertex u, Graph& g) {
      invoke_visitors(m_vis, u, g, on_finish_vertex());      
    }
  protected:
    Visitors m_vis;
  };
  template <class Visitors>
  dfs_visitor<Visitors>
  make_dfs_visitor(Visitors vis) {
    return dfs_visitor<Visitors>(vis);
  }

} // namespace boost


#endif
