/* -*- C++ -*-

 * lemon/edge_set.h - Part of LEMON, a generic C++ optimization library

 *

 * Copyright (C) 2005 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_EDGE_SET_H

#define LEMON_EDGE_SET_H

/// \ingroup graphs

/// \file

/// \brief EdgeSet classes.

///

/// Graphs which use another graph's node-set as own. 

namespace lemon {

  template <typename _Graph>

  class ListEdgeSetBase {

  public:

    typedef _Graph Graph;

    typedef typename Graph::Node Node;

    typedef typename Graph::NodeIt NodeIt;

  protected:

    struct NodeT {

      int first_out, first_in;

      NodeT() : first_out(-1), first_in(-1) {}

    };

    typedef typename Graph::template NodeMap<NodeT> NodesImplBase;

    NodesImplBase* nodes;

    struct EdgeT {

      Node source, target;

      int next_out, next_in;

      int prev_out, prev_in;

      EdgeT() : prev_out(-1), prev_in(-1) {}

    };

    std::vector<EdgeT> edges;

    int first_edge;

    int first_free_edge;

    const Graph* graph;

    void initalize(const Graph& _graph, NodesImplBase& _nodes) {

      graph = &_graph;

      nodes = &_nodes;

    }

  public:

    class Edge {

      friend class ListEdgeSetBase<Graph>;

    protected:

      Edge(int _id) : id(_id) {}

      int id;

    public:

      Edge() {}

      Edge(Invalid) : id(-1) {}

      bool operator==(const Edge& edge) const { return id == edge.id; }

      bool operator!=(const Edge& edge) const { return id != edge.id; }

      bool operator<(const Edge& edge) const { return id < edge.id; }

    };

    ListEdgeSetBase() : first_edge(-1), first_free_edge(-1) {} 

    Edge addEdge(const Node& source, const Node& target) {

      int n;

      if (first_free_edge == -1) {

	n = edges.size();

	edges.push_back(EdgeT());

      } else {

	n = first_free_edge;

	first_free_edge = edges[first_free_edge].next_in;

      }

      edges[n].next_in = (*nodes)[target].first_in;

      (*nodes)[target].first_in = n;

      edges[n].next_out = (*nodes)[source].first_out;

      (*nodes)[source].first_out = n;

      edges[n].source = source;

      edges[n].target = target;

      return Edge(n);

    }

    void erase(const Edge& edge) {

      int n = edge.id;

      if (edges[n].prev_in != -1) {

	edges[edges[n].prev_in].next_in = edges[n].next_in;

      } else {

	(*nodes)[edges[n].target].first_in = edges[n].next_in;

      }

      if (edges[n].next_in != -1) {

	edges[edges[n].next_in].prev_in = edges[n].prev_in;

      }

      if (edges[n].prev_out != -1) {

	edges[edges[n].prev_out].next_out = edges[n].next_out;

      } else {

	(*nodes)[edges[n].source].first_out = edges[n].next_out;

      }

      if (edges[n].next_out != -1) {

	edges[edges[n].next_out].prev_out = edges[n].prev_out;

      }

    }

    void clear() {

      edges.clear();

      first_edge = -1;

      first_free_edge = -1;

    }

    void first(Node& node) const {

      graph->first(node);

    }

    void next(Node& node) const {

      graph->next(node);

    }

    void first(Edge& edge) const {

      Node node;

      for (first(node); node != INVALID && (*nodes)[node].first_in == -1; 

	   next(node));

      edge.id = (node == INVALID) ? -1 : (*nodes)[node].first_in;

    }

    void next(Edge& edge) const {

      if (edges[edge.id].next_in != -1) {

	edge.id = edges[edge.id].next_in;

      } else {

	Node node = edges[edge.id].target;

	for (next(node); node != INVALID && (*nodes)[node].first_in == -1; 

	     next(node));

	edge.id = (node == INVALID) ? -1 : (*nodes)[node].first_in;

      }      

    }

    void firstOut(Edge& edge, const Node& node) const {

      edge.id = (*nodes)[node].first_out;    

    }

    void nextOut(Edge& edge) const {

      edge.id = edges[edge.id].next_out;        

    }

    void firstIn(Edge& edge, const Node& node) const {

      edge.id = (*nodes)[node].first_in;          

    }

    void nextIn(Edge& edge) const {

      edge.id = edges[edge.id].next_in;    

    }

    int id(const Node& node) const { return graph->id(node); }

    int id(const Edge& edge) const { return edge.id; }

    Node nodeFromId(int id) const { return graph->fromId(id, Node()); }

    Edge edgeFromId(int id) const { return Edge(id); }

    int maxNodeId() const { return graph->maxId(Node()); };

    int maxEdgeId() const { return edges.size() - 1; }

    Node source(const Edge& edge) const { return edges[edge.id].source;}

    Node target(const Edge& edge) const { return edges[edge.id].target;}

    template <typename _Value>

    class NodeMap : public Graph::template NodeMap<_Value> {

    public:

      typedef typename _Graph::template NodeMap<_Value> Parent;

      explicit NodeMap(const ListEdgeSetBase<Graph>& edgeset) 

	: Parent(*edgeset.graph) { }

      NodeMap(const ListEdgeSetBase<Graph>& edgeset, const _Value& value)

	: Parent(*edgeset.graph, value) { }

    };

  };

  /// \ingroup graphs

  ///

  /// \brief Graph using a node set of another graph and an

  /// own edge set.

  ///

  /// This structure can be used to establish another graph over a node set

  /// of an existing one. The node iterator will go through the nodes of the

  /// original graph.

  ///

  /// \param _Graph The type of the graph which shares its node set with 

  /// this class. Its interface must conform to the \ref concept::StaticGraph

  /// "StaticGraph" concept.

  ///

  /// In the edge extension and removing it conforms to the 

  /// \ref concept::ExtendableGraph "ExtendableGraph" concept.

  template <typename _Graph>

  class ListEdgeSet :

    public ErasableEdgeSetExtender<

    ClearableEdgeSetExtender<

    ExtendableEdgeSetExtender<

    MappableEdgeSetExtender<

    IterableGraphExtender<

    AlterableEdgeSetExtender<

    GraphExtender<

    ListEdgeSetBase<_Graph> > > > > > > > {

  public:

    typedef ErasableEdgeSetExtender<

      ClearableEdgeSetExtender<

      ExtendableEdgeSetExtender<

      MappableEdgeSetExtender<

      IterableGraphExtender<

      AlterableEdgeSetExtender<

      GraphExtender<

      ListEdgeSetBase<_Graph> > > > > > > > Parent;

    typedef typename Parent::Node Node;

    typedef typename Parent::Edge Edge;

    typedef _Graph Graph;

    typedef typename Parent::NodesImplBase NodesImplBase;

    void eraseNode(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);

      }

    }

    void clearNodes() {

      Parent::clear();

    }

    class NodesImpl : public NodesImplBase {

    public:

      typedef NodesImplBase Parent;

      NodesImpl(const Graph& graph, ListEdgeSet& edgeset) 

	: Parent(graph), _edgeset(edgeset) {}

    protected:

      virtual void erase(const Node& node) {

	_edgeset.eraseNode(node);

	Parent::erase(node);

      }

      virtual void clear() {

	_edgeset.clearNodes();

	Parent::clear();

      }

    private:

      ListEdgeSet& _edgeset;

    };

    NodesImpl nodes;

  public:

    /// \brief Constructor of the adaptor.

    /// 

    /// Constructor of the adaptor.

    ListEdgeSet(const Graph& graph) : nodes(graph, *this) {

      Parent::initalize(graph, nodes);

    }

  };

  /// \ingroup graphs

  ///

  /// \brief Graph using a node set of another graph and an

  /// own undir edge set.

  ///

  /// This structure can be used to establish another graph over a node set

  /// of an existing one. The node iterator will go through the nodes of the

  /// original graph.

  ///

  /// \param _Graph The type of the graph which shares its node set with 

  /// this class. Its interface must conform to the \ref concept::StaticGraph

  /// "StaticGraph" concept.

  ///

  /// In the edge extension and removing it conforms to the 

  /// \ref concept::ExtendableGraph "ExtendableGraph" concept.

  template <typename _Graph>

  class ListUndirEdgeSet :

    public ErasableUndirEdgeSetExtender<

    ClearableUndirEdgeSetExtender<

    ExtendableUndirEdgeSetExtender<

    MappableUndirEdgeSetExtender<

    IterableUndirGraphExtender<

    AlterableUndirEdgeSetExtender<

    UndirGraphExtender<

    ListEdgeSetBase<_Graph> > > > > > > > {

  public:

    typedef ErasableUndirEdgeSetExtender<

      ClearableUndirEdgeSetExtender<

      ExtendableUndirEdgeSetExtender<

      MappableUndirEdgeSetExtender<

      IterableUndirGraphExtender<

      AlterableUndirEdgeSetExtender<

      UndirGraphExtender<

      ListEdgeSetBase<_Graph> > > > > > > > Parent;

    typedef typename Parent::Node Node;

    typedef typename Parent::Edge Edge;

    typedef _Graph Graph;

    typedef typename Parent::NodesImplBase NodesImplBase;

    void eraseNode(const Node& node) {

      Edge edge;

      Parent::firstOut(edge, node);

      while (edge != INVALID ) {

	erase(edge);

	Parent::firstOut(edge, node);

      } 

    }

    void clearNodes() {

      Parent::clear();

    }

    class NodesImpl : public NodesImplBase {

    public:

      typedef NodesImplBase Parent;

      NodesImpl(const Graph& graph, ListUndirEdgeSet& edgeset) 

	: Parent(graph), _edgeset(edgeset) {}

    protected:

      virtual void erase(const Node& node) {

	_edgeset.eraseNode(node);

	Parent::erase(node);

      }

      virtual void clear() {

	_edgeset.clearNodes();

	Parent::clear();

      }

    private:

      ListUndirEdgeSet& _edgeset;

    };

    NodesImpl nodes;

  public:

    /// \brief Constructor of the adaptor.

    /// 

    /// Constructor of the adaptor.

    ListUndirEdgeSet(const Graph& graph) : nodes(graph, *this) {

      Parent::initalize(graph, nodes);

    }

  };

}

#endif