/* -*- C++ -*-
 *
 * This file is a part of LEMON, a generic C++ optimization library
 *
 * Copyright (C) 2003-2006
 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
 * (Egervary Research Group on Combinatorial Optimization, EGRES).
 *
 * Permission to use, modify and distribute this software is granted
 * provided that this copyright notice appears in all copies. For
 * precise terms see the accompanying LICENSE file.
 *
 * This software is provided "AS IS" with no warranty of any kind,
 * express or implied, and with no claim as to its suitability for any
 * purpose.
 *
 */

#ifndef LEMON_GRAPH_EXTENDER_H
#define LEMON_GRAPH_EXTENDER_H

#include <lemon/invalid.h>
#include <lemon/error.h>

#include <lemon/bits/default_map.h>

namespace lemon {

  template <typename Base>
  class GraphExtender : public Base {
  public:

    typedef Base Parent;
    typedef GraphExtender Graph;

    // Base extensions

    typedef typename Parent::Node Node;
    typedef typename Parent::Edge Edge;

    int maxId(Node) const {
      return Parent::maxNodeId();
    }

    int maxId(Edge) const {
      return Parent::maxEdgeId();
    }

    Node fromId(int id, Node) const {
      return Parent::nodeFromId(id);
    }

    Edge fromId(int id, Edge) const {
      return Parent::edgeFromId(id);
    }

    Node oppositeNode(const Node &n, const Edge &e) const {
      if (n == Parent::source(e))
	return Parent::target(e);
      else if(n==Parent::target(e))
	return Parent::source(e);
      else
	return INVALID;
    }

    // Alterable extension

    typedef AlterationNotifier<Node> NodeNotifier;
    typedef AlterationNotifier<Edge> EdgeNotifier;


  protected:

    mutable NodeNotifier node_notifier;
    mutable EdgeNotifier edge_notifier;

  public:

    NodeNotifier& getNotifier(Node) const {
      return node_notifier;
    }
    
    EdgeNotifier& getNotifier(Edge) const {
      return edge_notifier;
    }

    class NodeIt : public Node { 
      const Graph* graph;
    public:

      NodeIt() {}

      NodeIt(Invalid i) : Node(i) { }

      explicit NodeIt(const Graph& _graph) : graph(&_graph) {
	_graph.first(*static_cast<Node*>(this));
      }

      NodeIt(const Graph& _graph, const Node& node) 
	: Node(node), graph(&_graph) {}

      NodeIt& operator++() { 
	graph->next(*this);
	return *this; 
      }

    };


    class EdgeIt : public Edge { 
      const Graph* graph;
    public:

      EdgeIt() { }

      EdgeIt(Invalid i) : Edge(i) { }

      explicit EdgeIt(const Graph& _graph) : graph(&_graph) {
	_graph.first(*static_cast<Edge*>(this));
      }

      EdgeIt(const Graph& _graph, const Edge& e) : 
	Edge(e), graph(&_graph) { }

      EdgeIt& operator++() { 
	graph->next(*this);
	return *this; 
      }

    };


    class OutEdgeIt : public Edge { 
      const Graph* graph;
    public:

      OutEdgeIt() { }

      OutEdgeIt(Invalid i) : Edge(i) { }

      OutEdgeIt(const Graph& _graph, const Node& node) 
	: graph(&_graph) {
	_graph.firstOut(*this, node);
      }

      OutEdgeIt(const Graph& _graph, const Edge& edge) 
	: Edge(edge), graph(&_graph) {}

      OutEdgeIt& operator++() { 
	graph->nextOut(*this);
	return *this; 
      }

    };


    class InEdgeIt : public Edge { 
      const Graph* graph;
    public:

      InEdgeIt() { }

      InEdgeIt(Invalid i) : Edge(i) { }

      InEdgeIt(const Graph& _graph, const Node& node) 
	: graph(&_graph) {
	_graph.firstIn(*this, node);
      }

      InEdgeIt(const Graph& _graph, const Edge& edge) : 
	Edge(edge), graph(&_graph) {}

      InEdgeIt& operator++() { 
	graph->nextIn(*this);
	return *this; 
      }

    };

    /// \brief Base node of the iterator
    ///
    /// Returns the base node (ie. the source in this case) of the iterator
    Node baseNode(const OutEdgeIt &e) const {
      return Parent::source(e);
    }
    /// \brief Running node of the iterator
    ///
    /// Returns the running node (ie. the target in this case) of the
    /// iterator
    Node runningNode(const OutEdgeIt &e) const {
      return Parent::target(e);
    }

    /// \brief Base node of the iterator
    ///
    /// Returns the base node (ie. the target in this case) of the iterator
    Node baseNode(const InEdgeIt &e) const {
      return Parent::target(e);
    }
    /// \brief Running node of the iterator
    ///
    /// Returns the running node (ie. the source in this case) of the
    /// iterator
    Node runningNode(const InEdgeIt &e) const {
      return Parent::source(e);
    }

    
    template <typename _Value>
    class NodeMap 
      : public IterableMapExtender<DefaultMap<Graph, Node, _Value> > {
    public:
      typedef GraphExtender Graph;
      typedef IterableMapExtender<DefaultMap<Graph, Node, _Value> > Parent;

      NodeMap(const Graph& _g) 
	: Parent(_g) {}
      NodeMap(const Graph& _g, const _Value& _v) 
	: Parent(_g, _v) {}

      NodeMap& operator=(const NodeMap& cmap) {
	return operator=<NodeMap>(cmap);
      }


      /// \brief Template assign operator.
      ///
      /// The given parameter should be conform to the ReadMap
      /// concecpt and could be indiced by the current item set of
      /// the NodeMap. In this case the value for each item
      /// is assigned by the value of the given ReadMap. 
      template <typename CMap>
      NodeMap& operator=(const CMap& cmap) {
	checkConcept<concept::ReadMap<Node, _Value>, CMap>();
	const typename Parent::Graph* graph = Parent::getGraph();
	Node it;
	for (graph->first(it); it != INVALID; graph->next(it)) {
	  Parent::set(it, cmap[it]);
	}
	return *this;
      }

    };

    template <typename _Value>
    class EdgeMap 
      : public IterableMapExtender<DefaultMap<Graph, Edge, _Value> > {
    public:
      typedef GraphExtender Graph;
      typedef IterableMapExtender<DefaultMap<Graph, Edge, _Value> > Parent;

      EdgeMap(const Graph& _g) 
	: Parent(_g) {}
      EdgeMap(const Graph& _g, const _Value& _v) 
	: Parent(_g, _v) {}

      EdgeMap& operator=(const EdgeMap& cmap) {
	return operator=<EdgeMap>(cmap);
      }

      template <typename CMap>
      EdgeMap& operator=(const CMap& cmap) {
	checkConcept<concept::ReadMap<Edge, _Value>, CMap>();
	const typename Parent::Graph* graph = Parent::getGraph();
	Edge it;
	for (graph->first(it); it != INVALID; graph->next(it)) {
	  Parent::set(it, cmap[it]);
	}
	return *this;
      }
    };


    Node addNode() {
      Node node = Parent::addNode();
      getNotifier(Node()).add(node);
      return node;
    }
    
    Edge addEdge(const Node& from, const Node& to) {
      Edge edge = Parent::addEdge(from, to);
      getNotifier(Edge()).add(edge);
      return edge;
    }

    void clear() {
      getNotifier(Edge()).clear();
      getNotifier(Node()).clear();
      Parent::clear();
    }


    void erase(const Node& node) {
      Edge edge;
      Parent::firstOut(edge, node);
      while (edge != INVALID ) {
	erase(edge);
	Parent::firstOut(edge, node);
      } 

      Parent::firstIn(edge, node);
      while (edge != INVALID ) {
	erase(edge);
	Parent::firstIn(edge, node);
      }

      getNotifier(Node()).erase(node);
      Parent::erase(node);
    }
    
    void erase(const Edge& edge) {
      getNotifier(Edge()).erase(edge);
      Parent::erase(edge);
    }


    ~GraphExtender() {
      getNotifier(Edge()).clear();
      getNotifier(Node()).clear();
    }
  };

  template <typename Base>
  class UGraphBaseExtender : public Base {

  public:

    typedef Base Parent;
    typedef typename Parent::Edge UEdge;
    typedef typename Parent::Node Node;

    typedef True UndirectedTag;

    class Edge : public UEdge {
      friend class UGraphBaseExtender;

    protected:
      bool forward;

      Edge(const UEdge &ue, bool _forward) :
        UEdge(ue), forward(_forward) {}

    public:
      Edge() {}

      /// Invalid edge constructor
      Edge(Invalid i) : UEdge(i), forward(true) {}

      bool operator==(const Edge &that) const {
	return forward==that.forward && UEdge(*this)==UEdge(that);
      }
      bool operator!=(const Edge &that) const {
	return forward!=that.forward || UEdge(*this)!=UEdge(that);
      }
      bool operator<(const Edge &that) const {
	return forward<that.forward ||
	  (!(that.forward<forward) && UEdge(*this)<UEdge(that));
      }
    };



    using Parent::source;

    /// Source of the given Edge.
    Node source(const Edge &e) const {
      return e.forward ? Parent::source(e) : Parent::target(e);
    }

    using Parent::target;

    /// Target of the given Edge.
    Node target(const Edge &e) const {
      return e.forward ? Parent::target(e) : Parent::source(e);
    }

    /// \brief Directed edge from an undirected edge.
    ///
    /// Returns a directed edge corresponding to the specified UEdge.
    /// If the given bool is true the given undirected edge and the
    /// returned edge have the same source node.
    Edge direct(const UEdge &ue, bool d) const {
      return Edge(ue, d);
    }

    /// Returns whether the given directed edge is same orientation as the
    /// corresponding undirected edge.
    ///
    /// \todo reference to the corresponding point of the undirected graph
    /// concept. "What does the direction of an undirected edge mean?"
    bool direction(const Edge &e) const { return e.forward; }


    using Parent::first;
    using Parent::next;

    void first(Edge &e) const {
      Parent::first(e);
      e.forward=true;
    }

    void next(Edge &e) const {
      if( e.forward ) {
	e.forward = false;
      }
      else {
	Parent::next(e);
	e.forward = true;
      }
    }

    void firstOut(Edge &e, const Node &n) const {
      Parent::firstIn(e,n);
      if( UEdge(e) != INVALID ) {
	e.forward = false;
      }
      else {
	Parent::firstOut(e,n);
	e.forward = true;
      }
    }
    void nextOut(Edge &e) const {
      if( ! e.forward ) {
	Node n = Parent::target(e);
	Parent::nextIn(e);
	if( UEdge(e) == INVALID ) {
	  Parent::firstOut(e, n);
	  e.forward = true;
	}
      }
      else {
	Parent::nextOut(e);
      }
    }

    void firstIn(Edge &e, const Node &n) const {
      Parent::firstOut(e,n);
      if( UEdge(e) != INVALID ) {
	e.forward = false;
      }
      else {
	Parent::firstIn(e,n);
	e.forward = true;
      }
    }
    void nextIn(Edge &e) const {
      if( ! e.forward ) {
	Node n = Parent::source(e);
	Parent::nextOut(e);
	if( UEdge(e) == INVALID ) {
	  Parent::firstIn(e, n);
	  e.forward = true;
	}
      }
      else {
	Parent::nextIn(e);
      }
    }

    void firstInc(UEdge &e, bool &d, const Node &n) const {
      d = true;
      Parent::firstOut(e, n);
      if (e != INVALID) return;
      d = false;
      Parent::firstIn(e, n);
    }

    void nextInc(UEdge &e, bool &d) const {
      if (d) {
	Node s = Parent::source(e);
	Parent::nextOut(e);
	if (e != INVALID) return;
	d = false;
	Parent::firstIn(e, s);
      } else {
	Parent::nextIn(e);
      }
    }

    Node nodeFromId(int id) const {
      return Parent::nodeFromId(id);
    }

    Edge edgeFromId(int id) const {
      return direct(Parent::edgeFromId(id >> 1), bool(id & 1));
    }

    UEdge uEdgeFromId(int id) const {
      return Parent::edgeFromId(id >> 1);
    }

    int id(const Node &n) const {
      return Parent::id(n);
    }

    int id(const UEdge &e) const {
      return Parent::id(e);
    }

    int id(const Edge &e) const {
      return 2 * Parent::id(e) + int(e.forward);
    }

    int maxNodeId() const {
      return Parent::maxNodeId();
    }

    int maxEdgeId() const {
      return 2 * Parent::maxEdgeId() + 1;
    }

    int maxUEdgeId() const {
      return Parent::maxEdgeId();
    }


    int edgeNum() const {
      return 2 * Parent::edgeNum();
    }

    int uEdgeNum() const {
      return Parent::edgeNum();
    }

    Edge findEdge(Node source, Node target, Edge prev) const {
      if (prev == INVALID) {
	UEdge edge = Parent::findEdge(source, target);
	if (edge != INVALID) return direct(edge, true);
	edge = Parent::findEdge(target, source);
	if (edge != INVALID) return direct(edge, false);
      } else if (direction(prev)) {
	UEdge edge = Parent::findEdge(source, target, prev);
	if (edge != INVALID) return direct(edge, true);
	edge = Parent::findEdge(target, source);
	if (edge != INVALID) return direct(edge, false);	
      } else {
	UEdge edge = Parent::findEdge(target, source, prev);
	if (edge != INVALID) return direct(edge, false);	      
      }
      return INVALID;
    }

    UEdge findUEdge(Node source, Node target, UEdge prev) const {
      if (prev == INVALID) {
	UEdge edge = Parent::findEdge(source, target);
	if (edge != INVALID) return edge;
	edge = Parent::findEdge(target, source);
	if (edge != INVALID) return edge;
      } else if (Parent::source(prev) == source) {
	UEdge edge = Parent::findEdge(source, target, prev);
	if (edge != INVALID) return edge;
	edge = Parent::findEdge(target, source);
	if (edge != INVALID) return edge;	
      } else {
	UEdge edge = Parent::findEdge(target, source, prev);
	if (edge != INVALID) return edge;	      
      }
      return INVALID;
    }
  };


  template <typename Base> 
  class UGraphExtender : public Base {
  public:
    
    typedef Base Parent;
    typedef UGraphExtender Graph;

    typedef typename Parent::Node Node;
    typedef typename Parent::Edge Edge;
    typedef typename Parent::UEdge UEdge;

    // UGraph extension    

    int maxId(Node) const {
      return Parent::maxNodeId();
    }

    int maxId(Edge) const {
      return Parent::maxEdgeId();
    }

    int maxId(UEdge) const {
      return Parent::maxUEdgeId();
    }

    Node fromId(int id, Node) const {
      return Parent::nodeFromId(id);
    }

    Edge fromId(int id, Edge) const {
      return Parent::edgeFromId(id);
    }

    UEdge fromId(int id, UEdge) const {
      return Parent::uEdgeFromId(id);
    }

    Node oppositeNode(const Node &n, const UEdge &e) const {
      if( n == Parent::source(e))
	return Parent::target(e);
      else if( n == Parent::target(e))
	return Parent::source(e);
      else
	return INVALID;
    }

    Edge oppositeEdge(const Edge &e) const {
      return Parent::direct(e, !Parent::direction(e));
    }

    using Parent::direct;
    Edge direct(const UEdge &ue, const Node &s) const {
      return Parent::direct(ue, Parent::source(ue) == s);
    }

    // Alterable extension

    typedef AlterationNotifier<Node> NodeNotifier;
    typedef AlterationNotifier<Edge> EdgeNotifier;
    typedef AlterationNotifier<UEdge> UEdgeNotifier;


  protected:

    mutable NodeNotifier node_notifier;
    mutable EdgeNotifier edge_notifier;
    mutable UEdgeNotifier uedge_notifier;

  public:

    NodeNotifier& getNotifier(Node) const {
      return node_notifier;
    }
    
    EdgeNotifier& getNotifier(Edge) const {
      return edge_notifier;
    }

    UEdgeNotifier& getNotifier(UEdge) const {
      return uedge_notifier;
    }



    class NodeIt : public Node { 
      const Graph* graph;
    public:

      NodeIt() {}

      NodeIt(Invalid i) : Node(i) { }

      explicit NodeIt(const Graph& _graph) : graph(&_graph) {
	_graph.first(*static_cast<Node*>(this));
      }

      NodeIt(const Graph& _graph, const Node& node) 
	: Node(node), graph(&_graph) {}

      NodeIt& operator++() { 
	graph->next(*this);
	return *this; 
      }

    };


    class EdgeIt : public Edge { 
      const Graph* graph;
    public:

      EdgeIt() { }

      EdgeIt(Invalid i) : Edge(i) { }

      explicit EdgeIt(const Graph& _graph) : graph(&_graph) {
	_graph.first(*static_cast<Edge*>(this));
      }

      EdgeIt(const Graph& _graph, const Edge& e) : 
	Edge(e), graph(&_graph) { }

      EdgeIt& operator++() { 
	graph->next(*this);
	return *this; 
      }

    };


    class OutEdgeIt : public Edge { 
      const Graph* graph;
    public:

      OutEdgeIt() { }

      OutEdgeIt(Invalid i) : Edge(i) { }

      OutEdgeIt(const Graph& _graph, const Node& node) 
	: graph(&_graph) {
	_graph.firstOut(*this, node);
      }

      OutEdgeIt(const Graph& _graph, const Edge& edge) 
	: Edge(edge), graph(&_graph) {}

      OutEdgeIt& operator++() { 
	graph->nextOut(*this);
	return *this; 
      }

    };


    class InEdgeIt : public Edge { 
      const Graph* graph;
    public:

      InEdgeIt() { }

      InEdgeIt(Invalid i) : Edge(i) { }

      InEdgeIt(const Graph& _graph, const Node& node) 
	: graph(&_graph) {
	_graph.firstIn(*this, node);
      }

      InEdgeIt(const Graph& _graph, const Edge& edge) : 
	Edge(edge), graph(&_graph) {}

      InEdgeIt& operator++() { 
	graph->nextIn(*this);
	return *this; 
      }

    };


    class UEdgeIt : public Parent::UEdge { 
      const Graph* graph;
    public:

      UEdgeIt() { }

      UEdgeIt(Invalid i) : UEdge(i) { }

      explicit UEdgeIt(const Graph& _graph) : graph(&_graph) {
	_graph.first(*static_cast<UEdge*>(this));
      }

      UEdgeIt(const Graph& _graph, const UEdge& e) : 
	UEdge(e), graph(&_graph) { }

      UEdgeIt& operator++() { 
	graph->next(*this);
	return *this; 
      }

    };

    class IncEdgeIt : public Parent::UEdge {
      friend class UGraphExtender;
      const Graph* graph;
      bool direction;
    public:

      IncEdgeIt() { }

      IncEdgeIt(Invalid i) : UEdge(i), direction(false) { }

      IncEdgeIt(const Graph& _graph, const Node &n) : graph(&_graph) {
	_graph.firstInc(*this, direction, n);
      }

      IncEdgeIt(const Graph& _graph, const UEdge &ue, const Node &n)
	: graph(&_graph), UEdge(ue) {
	direction = (_graph.source(ue) == n);
      }

      IncEdgeIt& operator++() {
	graph->nextInc(*this, direction);
	return *this; 
      }
    };

    /// \brief Base node of the iterator
    ///
    /// Returns the base node (ie. the source in this case) of the iterator
    Node baseNode(const OutEdgeIt &e) const {
      return Parent::source((Edge)e);
    }
    /// \brief Running node of the iterator
    ///
    /// Returns the running node (ie. the target in this case) of the
    /// iterator
    Node runningNode(const OutEdgeIt &e) const {
      return Parent::target((Edge)e);
    }

    /// \brief Base node of the iterator
    ///
    /// Returns the base node (ie. the target in this case) of the iterator
    Node baseNode(const InEdgeIt &e) const {
      return Parent::target((Edge)e);
    }
    /// \brief Running node of the iterator
    ///
    /// Returns the running node (ie. the source in this case) of the
    /// iterator
    Node runningNode(const InEdgeIt &e) const {
      return Parent::source((Edge)e);
    }

    /// Base node of the iterator
    ///
    /// Returns the base node of the iterator
    Node baseNode(const IncEdgeIt &e) const {
      return e.direction ? source(e) : target(e);
    }
    /// Running node of the iterator
    ///
    /// Returns the running node of the iterator
    Node runningNode(const IncEdgeIt &e) const {
      return e.direction ? target(e) : source(e);
    }

    // Mappable extension

    template <typename _Value>
    class NodeMap 
      : public IterableMapExtender<DefaultMap<Graph, Node, _Value> > {
    public:
      typedef UGraphExtender Graph;
      typedef IterableMapExtender<DefaultMap<Graph, Node, _Value> > Parent;

      NodeMap(const Graph& _g) 
	: Parent(_g) {}
      NodeMap(const Graph& _g, const _Value& _v) 
	: Parent(_g, _v) {}

      NodeMap& operator=(const NodeMap& cmap) {
	return operator=<NodeMap>(cmap);
      }


      /// \brief Template assign operator.
      ///
      /// The given parameter should be conform to the ReadMap
      /// concecpt and could be indiced by the current item set of
      /// the NodeMap. In this case the value for each item
      /// is assigned by the value of the given ReadMap. 
      template <typename CMap>
      NodeMap& operator=(const CMap& cmap) {
	checkConcept<concept::ReadMap<Node, _Value>, CMap>();
	const typename Parent::Graph* graph = Parent::getGraph();
	Node it;
	for (graph->first(it); it != INVALID; graph->next(it)) {
	  Parent::set(it, cmap[it]);
	}
	return *this;
      }

    };

    template <typename _Value>
    class EdgeMap 
      : public IterableMapExtender<DefaultMap<Graph, Edge, _Value> > {
    public:
      typedef UGraphExtender Graph;
      typedef IterableMapExtender<DefaultMap<Graph, Edge, _Value> > Parent;

      EdgeMap(const Graph& _g) 
	: Parent(_g) {}
      EdgeMap(const Graph& _g, const _Value& _v) 
	: Parent(_g, _v) {}

      EdgeMap& operator=(const EdgeMap& cmap) {
	return operator=<EdgeMap>(cmap);
      }

      template <typename CMap>
      EdgeMap& operator=(const CMap& cmap) {
	checkConcept<concept::ReadMap<Edge, _Value>, CMap>();
	const typename Parent::Graph* graph = Parent::getGraph();
	Edge it;
	for (graph->first(it); it != INVALID; graph->next(it)) {
	  Parent::set(it, cmap[it]);
	}
	return *this;
      }
    };


    template <typename _Value>
    class UEdgeMap 
      : public IterableMapExtender<DefaultMap<Graph, UEdge, _Value> > {
    public:
      typedef UGraphExtender Graph;
      typedef IterableMapExtender<DefaultMap<Graph, UEdge, _Value> > Parent;

      UEdgeMap(const Graph& _g) 
	: Parent(_g) {}
      UEdgeMap(const Graph& _g, const _Value& _v) 
	: Parent(_g, _v) {}

      UEdgeMap& operator=(const UEdgeMap& cmap) {
	return operator=<UEdgeMap>(cmap);
      }

      template <typename CMap>
      UEdgeMap& operator=(const CMap& cmap) {
	checkConcept<concept::ReadMap<UEdge, _Value>, CMap>();
	const typename Parent::Graph* graph = Parent::getGraph();
	UEdge it;
	for (graph->first(it); it != INVALID; graph->next(it)) {
	  Parent::set(it, cmap[it]);
	}
	return *this;
      }
    };

    // Alteration extension

    Node addNode() {
      Node node = Parent::addNode();
      getNotifier(Node()).add(node);
      return node;
    }

    UEdge addEdge(const Node& from, const Node& to) {
      UEdge uedge = Parent::addEdge(from, to);
      getNotifier(UEdge()).add(uedge);
      getNotifier(Edge()).add(Parent::direct(uedge, true));
      getNotifier(Edge()).add(Parent::direct(uedge, false));
      return uedge;
    }
    
    void clear() {
      getNotifier(Edge()).clear();
      getNotifier(UEdge()).clear();
      getNotifier(Node()).clear();
      Parent::clear();
    }

    void erase(const Node& node) {
      Edge edge;
      Parent::firstOut(edge, node);
      while (edge != INVALID ) {
	erase(edge);
	Parent::firstOut(edge, node);
      } 

      Parent::firstIn(edge, node);
      while (edge != INVALID ) {
	erase(edge);
	Parent::firstIn(edge, node);
      }

      getNotifier(Node()).erase(node);
      Parent::erase(node);
    }

    void erase(const UEdge& uedge) {
      getNotifier(Edge()).erase(Parent::direct(uedge, true));
      getNotifier(Edge()).erase(Parent::direct(uedge, false));
      getNotifier(UEdge()).erase(uedge);
      Parent::erase(uedge);
    }

    ~UGraphExtender() {
      getNotifier(Edge()).clear();
      getNotifier(UEdge()).clear();
      getNotifier(Node()).clear();
    }

  };


  template <typename Base>
  class BpUGraphBaseExtender : public Base {
  public:
    typedef Base Parent;
    typedef BpUGraphBaseExtender Graph;

    typedef typename Parent::Node Node;
    typedef typename Parent::Edge UEdge;


    using Parent::first;
    using Parent::next;

    using Parent::id;

    class ANode : public Node {
      friend class BpUGraphBaseExtender;
    public:
      ANode() {}
      ANode(const Node& node) : Node(node) {
	LEMON_ASSERT(Parent::aNode(node) || node == INVALID, 
		     typename Parent::NodeSetError());
      }
      ANode(Invalid) : Node(INVALID) {}
    };

    void first(ANode& node) const {
      Parent::firstANode(static_cast<Node&>(node));
    }
    void next(ANode& node) const {
      Parent::nextANode(static_cast<Node&>(node));
    }

    int id(const ANode& node) const {
      return Parent::aNodeId(node);
    }

    class BNode : public Node {
      friend class BpUGraphBaseExtender;
    public:
      BNode() {}
      BNode(const Node& node) : Node(node) {
	LEMON_ASSERT(Parent::bNode(node) || node == INVALID,
		     typename Parent::NodeSetError());
      }
      BNode(Invalid) : Node(INVALID) {}
    };

    void first(BNode& node) const {
      Parent::firstBNode(static_cast<Node&>(node));
    }
    void next(BNode& node) const {
      Parent::nextBNode(static_cast<Node&>(node));
    }
  
    int id(const BNode& node) const {
      return Parent::aNodeId(node);
    }

    Node source(const UEdge& edge) const {
      return aNode(edge);
    }
    Node target(const UEdge& edge) const {
      return bNode(edge);
    }

    void firstInc(UEdge& edge, bool& direction, const Node& node) const {
      if (Parent::aNode(node)) {
	Parent::firstOut(edge, node);
	direction = true;
      } else {
	Parent::firstIn(edge, node);
	direction = static_cast<UEdge&>(edge) == INVALID;
      }
    }
    void nextInc(UEdge& edge, bool& direction) const {
      if (direction) {
	Parent::nextOut(edge);
      } else {
	Parent::nextIn(edge);
	if (edge == INVALID) direction = true;
      }
    }

    int maxUEdgeId() const {
      return Parent::maxEdgeId();
    }

    UEdge uEdgeFromId(int id) const {
      return Parent::edgeFromId(id);
    }

    class Edge : public UEdge {
      friend class BpUGraphBaseExtender;
    protected:
      bool forward;

      Edge(const UEdge& edge, bool _forward)
	: UEdge(edge), forward(_forward) {}

    public:
      Edge() {}
      Edge (Invalid) : UEdge(INVALID), forward(true) {}
      bool operator==(const Edge& i) const {
	return UEdge::operator==(i) && forward == i.forward;
      }
      bool operator!=(const Edge& i) const {
	return UEdge::operator!=(i) || forward != i.forward;
      }
      bool operator<(const Edge& i) const {
	return UEdge::operator<(i) || 
	  (!(i.forward<forward) && UEdge(*this)<UEdge(i));
      }
    };

    void first(Edge& edge) const {
      Parent::first(static_cast<UEdge&>(edge));
      edge.forward = true;
    }

    void next(Edge& edge) const {
      if (!edge.forward) {
	Parent::next(static_cast<UEdge&>(edge));
      }
      edge.forward = !edge.forward;
    }

    void firstOut(Edge& edge, const Node& node) const {
      if (Parent::aNode(node)) {
	Parent::firstOut(edge, node);
	edge.forward = true;
      } else {
	Parent::firstIn(edge, node);
	edge.forward = static_cast<UEdge&>(edge) == INVALID;
      }
    }
    void nextOut(Edge& edge) const {
      if (edge.forward) {
	Parent::nextOut(edge);
      } else {
	Parent::nextIn(edge);
        edge.forward = static_cast<UEdge&>(edge) == INVALID;
      }
    }

    void firstIn(Edge& edge, const Node& node) const {
      if (Parent::bNode(node)) {
	Parent::firstIn(edge, node);
	edge.forward = true;	
      } else {
	Parent::firstOut(edge, node);
	edge.forward = static_cast<UEdge&>(edge) == INVALID;
      }
    }
    void nextIn(Edge& edge) const {
      if (edge.forward) {
	Parent::nextIn(edge);
      } else {
	Parent::nextOut(edge);
	edge.forward = static_cast<UEdge&>(edge) == INVALID;
      }
    }

    Node source(const Edge& edge) const {
      return edge.forward ? Parent::aNode(edge) : Parent::bNode(edge);
    }
    Node target(const Edge& edge) const {
      return edge.forward ? Parent::bNode(edge) : Parent::aNode(edge);
    }

    int id(const Edge& edge) const {
      return (Parent::id(edge) << 1) + (edge.forward ? 0 : 1);
    }
    Edge edgeFromId(int id) const {
      return Edge(Parent::fromId(id >> 1, UEdge()), (id & 1) == 0);
    }
    int maxEdgeId() const {
      return (Parent::maxId(UEdge()) << 1) + 1;
    }

    bool direction(const Edge& edge) const {
      return edge.forward;
    }

    Edge direct(const UEdge& edge, bool direction) const {
      return Edge(edge, direction);
    }
  };

  template <typename Base>
  class BpUGraphExtender : public Base {
  public:
    typedef Base Parent;
    typedef BpUGraphExtender Graph;

    typedef typename Parent::Node Node;
    typedef typename Parent::BNode BNode;
    typedef typename Parent::ANode ANode;
    typedef typename Parent::Edge Edge;
    typedef typename Parent::UEdge UEdge;

    Node oppositeNode(const UEdge& edge, const Node& node) const {
      return source(edge) == node ? 
	target(edge) : source(edge);
    }

    using Parent::direct;
    Edge direct(const UEdge& edge, const Node& node) const {
      return Edge(edge, node == Parent::source(edge));
    }

    Edge oppositeEdge(const Edge& edge) const {
      return Parent::direct(edge, !Parent::direction(edge));
    }


    int maxId(Node) const {
      return Parent::maxNodeId();
    }
    int maxId(BNode) const {
      return Parent::maxBNodeId();
    }
    int maxId(ANode) const {
      return Parent::maxANodeId();
    }
    int maxId(Edge) const {
      return Parent::maxEdgeId();
    }
    int maxId(UEdge) const {
      return Parent::maxUEdgeId();
    }


    Node fromId(int id, Node) const {
      return Parent::nodeFromId(id);
    }
    ANode fromId(int id, ANode) const {
      return Parent::fromANodeId(id);
    }
    BNode fromId(int id, BNode) const {
      return Parent::fromBNodeId(id);
    }
    Edge fromId(int id, Edge) const {
      return Parent::edgeFromId(id);
    }
    UEdge fromId(int id, UEdge) const {
      return Parent::uEdgeFromId(id);
    }  
  
    typedef AlterationNotifier<Node> NodeNotifier;
    typedef AlterationNotifier<BNode> BNodeNotifier;
    typedef AlterationNotifier<ANode> ANodeNotifier;
    typedef AlterationNotifier<Edge> EdgeNotifier;
    typedef AlterationNotifier<UEdge> UEdgeNotifier;

  protected:

    mutable NodeNotifier nodeNotifier;
    mutable BNodeNotifier bNodeNotifier;
    mutable ANodeNotifier aNodeNotifier;
    mutable EdgeNotifier edgeNotifier;
    mutable UEdgeNotifier uEdgeNotifier;

  public:

    NodeNotifier& getNotifier(Node) const {
      return nodeNotifier;
    }

    BNodeNotifier& getNotifier(BNode) const {
      return bNodeNotifier;
    }

    ANodeNotifier& getNotifier(ANode) const {
      return aNodeNotifier;
    }

    EdgeNotifier& getNotifier(Edge) const {
      return edgeNotifier;
    }

    UEdgeNotifier& getNotifier(UEdge) const {
      return uEdgeNotifier;
    }

    ~BpUGraphExtender() {
      getNotifier(UEdge()).clear();
      getNotifier(Edge()).clear();
      getNotifier(ANode()).clear();
      getNotifier(BNode()).clear();
      getNotifier(Node()).clear();
    }

  
    class NodeIt : public Node { 
      const Graph* graph;
    public:
    
      NodeIt() { }
    
      NodeIt(Invalid i) : Node(INVALID) { }
    
      explicit NodeIt(const Graph& _graph) : graph(&_graph) {
	graph->first(static_cast<Node&>(*this));
      }

      NodeIt(const Graph& _graph, const Node& node) 
	: Node(node), graph(&_graph) { }
    
      NodeIt& operator++() { 
	graph->next(*this);
	return *this; 
      }

    };

    class ANodeIt : public Node { 
      friend class BpUGraphExtender;
      const Graph* graph;
    public:
    
      ANodeIt() { }
    
      ANodeIt(Invalid i) : Node(INVALID) { }
    
      explicit ANodeIt(const Graph& _graph) : graph(&_graph) {
	graph->firstANode(static_cast<Node&>(*this));
      }

      ANodeIt(const Graph& _graph, const Node& node) 
	: Node(node), graph(&_graph) {}
    
      ANodeIt& operator++() { 
	graph->nextANode(*this);
	return *this; 
      }
    };

    class BNodeIt : public Node { 
      friend class BpUGraphExtender;
      const Graph* graph;
    public:
    
      BNodeIt() { }
    
      BNodeIt(Invalid i) : Node(INVALID) { }
    
      explicit BNodeIt(const Graph& _graph) : graph(&_graph) {
	graph->firstBNode(static_cast<Node&>(*this));
      }

      BNodeIt(const Graph& _graph, const Node& node) 
	: Node(node), graph(&_graph) {}
    
      BNodeIt& operator++() { 
	graph->nextBNode(*this);
	return *this; 
      }
    };

    class EdgeIt : public Edge { 
      friend class BpUGraphExtender;
      const Graph* graph;
    public:
    
      EdgeIt() { }
    
      EdgeIt(Invalid i) : Edge(INVALID) { }
    
      explicit EdgeIt(const Graph& _graph) : graph(&_graph) {
	graph->first(static_cast<Edge&>(*this));
      }

      EdgeIt(const Graph& _graph, const Edge& edge) 
	: Edge(edge), graph(&_graph) { }
    
      EdgeIt& operator++() { 
	graph->next(*this);
	return *this; 
      }

    };

    class UEdgeIt : public UEdge { 
      friend class BpUGraphExtender;
      const Graph* graph;
    public:
    
      UEdgeIt() { }
    
      UEdgeIt(Invalid i) : UEdge(INVALID) { }
    
      explicit UEdgeIt(const Graph& _graph) : graph(&_graph) {
	graph->first(static_cast<UEdge&>(*this));
      }

      UEdgeIt(const Graph& _graph, const UEdge& edge) 
	: UEdge(edge), graph(&_graph) { }
    
      UEdgeIt& operator++() { 
	graph->next(*this);
	return *this; 
      }
    };

    class OutEdgeIt : public Edge { 
      friend class BpUGraphExtender;
      const Graph* graph;
    public:
    
      OutEdgeIt() { }
    
      OutEdgeIt(Invalid i) : Edge(i) { }
    
      OutEdgeIt(const Graph& _graph, const Node& node) 
	: graph(&_graph) {
	graph->firstOut(*this, node);
      }
    
      OutEdgeIt(const Graph& _graph, const Edge& edge) 
	: Edge(edge), graph(&_graph) {}
    
      OutEdgeIt& operator++() { 
	graph->nextOut(*this);
	return *this; 
      }

    };


    class InEdgeIt : public Edge { 
      friend class BpUGraphExtender;
      const Graph* graph;
    public:
    
      InEdgeIt() { }
    
      InEdgeIt(Invalid i) : Edge(i) { }
    
      InEdgeIt(const Graph& _graph, const Node& node) 
	: graph(&_graph) {
	graph->firstIn(*this, node);
      }
    
      InEdgeIt(const Graph& _graph, const Edge& edge) : 
	Edge(edge), graph(&_graph) {}
    
      InEdgeIt& operator++() { 
	graph->nextIn(*this);
	return *this; 
      }

    };
  
    /// \brief Base node of the iterator
    ///
    /// Returns the base node (ie. the source in this case) of the iterator
    Node baseNode(const OutEdgeIt &e) const {
      return Parent::source((Edge&)e);
    }
    /// \brief Running node of the iterator
    ///
    /// Returns the running node (ie. the target in this case) of the
    /// iterator
    Node runningNode(const OutEdgeIt &e) const {
      return Parent::target((Edge&)e);
    }
  
    /// \brief Base node of the iterator
    ///
    /// Returns the base node (ie. the target in this case) of the iterator
    Node baseNode(const InEdgeIt &e) const {
      return Parent::target((Edge&)e);
    }
    /// \brief Running node of the iterator
    ///
    /// Returns the running node (ie. the source in this case) of the
    /// iterator
    Node runningNode(const InEdgeIt &e) const {
      return Parent::source((Edge&)e);
    }
  
    class IncEdgeIt : public Parent::UEdge { 
      friend class BpUGraphExtender;
      const Graph* graph;
      bool direction;
    public:
    
      IncEdgeIt() { }
    
      IncEdgeIt(Invalid i) : UEdge(i), direction(true) { }
    
      IncEdgeIt(const Graph& _graph, const Node &n) : graph(&_graph) {
	graph->firstInc(*this, direction, n);
      }

      IncEdgeIt(const Graph& _graph, const UEdge &ue, const Node &n)
	: graph(&_graph), UEdge(ue) {
	direction = (graph->source(ue) == n);
      }

      IncEdgeIt& operator++() {
	graph->nextInc(*this, direction);
	return *this; 
      }
    };
  

    /// Base node of the iterator
    ///
    /// Returns the base node of the iterator
    Node baseNode(const IncEdgeIt &e) const {
      return e.direction ? source(e) : target(e);
    }

    /// Running node of the iterator
    ///
    /// Returns the running node of the iterator
    Node runningNode(const IncEdgeIt &e) const {
      return e.direction ? target(e) : source(e);
    }

    template <typename _Value>
    class ANodeMap 
      : public IterableMapExtender<DefaultMap<Graph, ANode, _Value> > {
    public:
      typedef BpUGraphExtender Graph;
      typedef IterableMapExtender<DefaultMap<Graph, ANode, _Value> > 
      Parent;
    
      ANodeMap(const Graph& _g) 
	: Parent(_g) {}
      ANodeMap(const Graph& _g, const _Value& _v) 
	: Parent(_g, _v) {}
    
      ANodeMap& operator=(const ANodeMap& cmap) {
	return operator=<ANodeMap>(cmap);
      }
    

      /// \brief Template assign operator.
      ///
      /// The given parameter should be conform to the ReadMap
      /// concept and could be indiced by the current item set of
      /// the ANodeMap. In this case the value for each item
      /// is assigned by the value of the given ReadMap. 
      template <typename CMap>
      ANodeMap& operator=(const CMap& cmap) {
	checkConcept<concept::ReadMap<ANode, _Value>, CMap>();
	const typename Parent::Graph* graph = Parent::getGraph();
	ANode it;
	for (graph->first(it); it != INVALID; graph->next(it)) {
	  Parent::set(it, cmap[it]);
	}
	return *this;
      }
    
    };

    template <typename _Value>
    class BNodeMap 
      : public IterableMapExtender<DefaultMap<Graph, BNode, _Value> > {
    public:
      typedef BpUGraphExtender Graph;
      typedef IterableMapExtender<DefaultMap<Graph, BNode, _Value> > 
      Parent;
    
      BNodeMap(const Graph& _g) 
	: Parent(_g) {}
      BNodeMap(const Graph& _g, const _Value& _v) 
	: Parent(_g, _v) {}
    
      BNodeMap& operator=(const BNodeMap& cmap) {
	return operator=<BNodeMap>(cmap);
      }
    

      /// \brief Template assign operator.
      ///
      /// The given parameter should be conform to the ReadMap
      /// concept and could be indiced by the current item set of
      /// the BNodeMap. In this case the value for each item
      /// is assigned by the value of the given ReadMap. 
      template <typename CMap>
      BNodeMap& operator=(const CMap& cmap) {
	checkConcept<concept::ReadMap<BNode, _Value>, CMap>();
	const typename Parent::Graph* graph = Parent::getGraph();
	BNode it;
	for (graph->first(it); it != INVALID; graph->next(it)) {
	  Parent::set(it, cmap[it]);
	}
	return *this;
      }
    
    };

  protected:

    template <typename _Value>
    class NodeMapBase : public NodeNotifier::ObserverBase {
    public:
      typedef BpUGraphExtender Graph;

      typedef Node Key;
      typedef _Value Value;

      /// The reference type of the map;
      typedef typename BNodeMap<_Value>::Reference Reference;
      /// The pointer type of the map;
      typedef typename BNodeMap<_Value>::Pointer Pointer;
      
      /// The const value type of the map.
      typedef const Value ConstValue;
      /// The const reference type of the map;
      typedef typename BNodeMap<_Value>::ConstReference ConstReference;
      /// The pointer type of the map;
      typedef typename BNodeMap<_Value>::ConstPointer ConstPointer;

      typedef True ReferenceMapTag;

      NodeMapBase(const Graph& _g) 
	: graph(&_g), bNodeMap(_g), aNodeMap(_g) {
	NodeNotifier::ObserverBase::attach(_g.getNotifier(Node()));
      }
      NodeMapBase(const Graph& _g, const _Value& _v) 
	: graph(&_g), bNodeMap(_g, _v), 
	  aNodeMap(_g, _v) {
	NodeNotifier::ObserverBase::attach(_g.getNotifier(Node()));
      }

      virtual ~NodeMapBase() {      
	if (NodeNotifier::ObserverBase::attached()) {
          NodeNotifier::ObserverBase::detach();
	}
      }
    
      ConstReference operator[](const Key& node) const {
	if (Parent::aNode(node)) {
	  return aNodeMap[node];
	} else {
	  return bNodeMap[node];
	}
      } 

      Reference operator[](const Key& node) {
	if (Parent::aNode(node)) {
	  return aNodeMap[node];
	} else {
	  return bNodeMap[node];
	}
      }

      void set(const Key& node, const Value& value) {
	if (Parent::aNode(node)) {
	  aNodeMap.set(node, value);
	} else {
	  bNodeMap.set(node, value);
	}
      }

    protected:
      
      virtual void add(const Node&) {}
      virtual void add(const std::vector<Node>&) {}
      virtual void erase(const Node&) {}
      virtual void erase(const std::vector<Node>&) {}
      virtual void clear() {}
      virtual void build() {}

      const Graph* getGraph() const { return graph; }
      
    private:
      const Graph* graph;
      BNodeMap<_Value> bNodeMap;
      ANodeMap<_Value> aNodeMap;
    };
    
  public:

    template <typename _Value>
    class NodeMap 
      : public IterableMapExtender<NodeMapBase<_Value> > {
    public:
      typedef BpUGraphExtender Graph;
      typedef IterableMapExtender< NodeMapBase<_Value> > Parent;
    
      NodeMap(const Graph& _g) 
	: Parent(_g) {}
      NodeMap(const Graph& _g, const _Value& _v) 
	: Parent(_g, _v) {}
    
      NodeMap& operator=(const NodeMap& cmap) {
	return operator=<NodeMap>(cmap);
      }
    

      /// \brief Template assign operator.
      ///
      /// The given parameter should be conform to the ReadMap
      /// concept and could be indiced by the current item set of
      /// the NodeMap. In this case the value for each item
      /// is assigned by the value of the given ReadMap. 
      template <typename CMap>
      NodeMap& operator=(const CMap& cmap) {
	checkConcept<concept::ReadMap<Node, _Value>, CMap>();
	const typename Parent::Graph* graph = Parent::getGraph();
	Node it;
	for (graph->first(it); it != INVALID; graph->next(it)) {
	  Parent::set(it, cmap[it]);
	}
	return *this;
      }
    
    };



    template <typename _Value>
    class EdgeMap 
      : public IterableMapExtender<DefaultMap<Graph, Edge, _Value> > {
    public:
      typedef BpUGraphExtender Graph;
      typedef IterableMapExtender<DefaultMap<Graph, Edge, _Value> > Parent;
    
      EdgeMap(const Graph& _g) 
	: Parent(_g) {}
      EdgeMap(const Graph& _g, const _Value& _v) 
	: Parent(_g, _v) {}
    
      EdgeMap& operator=(const EdgeMap& cmap) {
	return operator=<EdgeMap>(cmap);
      }
    
      template <typename CMap>
      EdgeMap& operator=(const CMap& cmap) {
	checkConcept<concept::ReadMap<Edge, _Value>, CMap>();
	const typename Parent::Graph* graph = Parent::getGraph();
	Edge it;
	for (graph->first(it); it != INVALID; graph->next(it)) {
	  Parent::set(it, cmap[it]);
	}
	return *this;
      }
    };

    template <typename _Value>
    class UEdgeMap 
      : public IterableMapExtender<DefaultMap<Graph, UEdge, _Value> > {
    public:
      typedef BpUGraphExtender Graph;
      typedef IterableMapExtender<DefaultMap<Graph, UEdge, _Value> > 
      Parent;
    
      UEdgeMap(const Graph& _g) 
	: Parent(_g) {}
      UEdgeMap(const Graph& _g, const _Value& _v) 
	: Parent(_g, _v) {}
    
      UEdgeMap& operator=(const UEdgeMap& cmap) {
	return operator=<UEdgeMap>(cmap);
      }
    
      template <typename CMap>
      UEdgeMap& operator=(const CMap& cmap) {
	checkConcept<concept::ReadMap<UEdge, _Value>, CMap>();
	const typename Parent::Graph* graph = Parent::getGraph();
	UEdge it;
	for (graph->first(it); it != INVALID; graph->next(it)) {
	  Parent::set(it, cmap[it]);
	}
	return *this;
      }
    };

  
    Node addANode() {
      Node node = Parent::addANode();
      getNotifier(ANode()).add(node);
      getNotifier(Node()).add(node);
      return node;
    }

    Node addBNode() {
      Node node = Parent::addBNode();
      getNotifier(BNode()).add(node);
      getNotifier(Node()).add(node);
      return node;
    }
  
    UEdge addEdge(const Node& source, const Node& target) {
      UEdge uedge = Parent::addEdge(source, target);
      getNotifier(UEdge()).add(uedge);
    
      std::vector<Edge> edges;
      edges.push_back(direct(uedge, true));
      edges.push_back(direct(uedge, false));
      getNotifier(Edge()).add(edges);
    
      return uedge;
    }

    void clear() {
      getNotifier(Edge()).clear();
      getNotifier(UEdge()).clear();
      getNotifier(Node()).clear();
      getNotifier(BNode()).clear();
      getNotifier(ANode()).clear();
      Parent::clear();
    }

    void erase(const Node& node) {
      UEdge uedge;
      bool dir;
      Parent::firstInc(uedge, dir, node);
      while (uedge != INVALID ) {
	erase(uedge);
	Parent::firstInc(uedge, dir, node);
      } 

      getNotifier(Node()).erase(node);
      Parent::erase(node);
    }
    
    void erase(const UEdge& uedge) {
      std::vector<Edge> edges;
      edges.push_back(direct(uedge, true));
      edges.push_back(direct(uedge, false));
      getNotifier(Edge()).erase(edges);
      getNotifier(UEdge()).erase(uedge);
      Parent::erase(uedge);
    }


    ~BpUGraphExtender() {
      getNotifier(Edge()).clear();
      getNotifier(UEdge()).clear();
      getNotifier(Node()).clear();
      getNotifier(BNode()).clear();
      getNotifier(ANode()).clear();
    }


  };

}

#endif // LEMON_UNDIR_GRAPH_EXTENDER_H