/* -*- C++ -*-

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

 *

 * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

 * (Egervary Combinatorial Optimization Research Group, 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_FULL_GRAPH_H

#define LEMON_FULL_GRAPH_H

#include <lemon/idmappable_graph_extender.h>

#include <lemon/iterable_graph_extender.h>

#include <lemon/alteration_observer_registry.h>

#include <lemon/default_map.h>

///\ingroup graphs

///\file

///\brief FullGraph and SymFullGraph classes.

#include <lemon/invalid.h>

namespace lemon {

/// \addtogroup graphs

/// @{

  ///A full graph class.

  ///This is a simple and fast directed full graph implementation.

  ///It is completely static, so you can neither add nor delete either

  ///edges or nodes.

  ///Thus it conforms to

  ///the \ref skeleton::StaticGraph "StaticGraph" concept

  ///\sa skeleton::StaticGraph.

  ///\todo What about loops?

  ///\todo Don't we need SymEdgeMap?

  ///

  ///\author Alpar Juttner

  class FullGraphBase {

    int NodeNum;

    int EdgeNum;

  public:

    typedef FullGraphBase Graph;

    class Node;

    class Edge;

  public:

    FullGraphBase() {}

    ///Creates a full graph with \c n nodes.

    void construct(int n) { NodeNum = n; EdgeNum = n * n; }

    ///

    //    FullGraphBase(const FullGraphBase &_g)

    //      : NodeNum(_g.nodeNum()), EdgeNum(NodeNum*NodeNum) { }

    ///Number of nodes.

    int nodeNum() const { return NodeNum; }

    ///Number of edges.

    int edgeNum() const { return EdgeNum; }

    /// Maximum node ID.

    /// Maximum node ID.

    ///\sa id(Node)

    int maxNodeId() const { return NodeNum-1; }

    /// Maximum edge ID.

    /// Maximum edge ID.

    ///\sa id(Edge)

    int maxEdgeId() const { return EdgeNum-1; }

    Node tail(Edge e) const { return e.id % NodeNum; }

    Node head(Edge e) const { return e.id / NodeNum; }

    /// Node ID.

    /// The ID of a valid Node is a nonnegative integer not greater than

    /// \ref maxNodeId(). The range of the ID's is not surely continuous

    /// and the greatest node ID can be actually less then \ref maxNodeId().

    ///

    /// The ID of the \ref INVALID node is -1.

    ///\return The ID of the node \c v. 

    static int id(Node v) { return v.id; }

    /// Edge ID.

    /// The ID of a valid Edge is a nonnegative integer not greater than

    /// \ref maxEdgeId(). The range of the ID's is not surely continuous

    /// and the greatest edge ID can be actually less then \ref maxEdgeId().

    ///

    /// The ID of the \ref INVALID edge is -1.

    ///\return The ID of the edge \c e. 

    static int id(Edge e) { return e.id; }

    /// Finds an edge between two nodes.

    /// Finds an edge from node \c u to node \c v.

    ///

    /// If \c prev is \ref INVALID (this is the default value), then

    /// It finds the first edge from \c u to \c v. Otherwise it looks for

    /// the next edge from \c u to \c v after \c prev.

    /// \return The found edge or INVALID if there is no such an edge.

    Edge findEdge(Node u,Node v, Edge prev = INVALID) 

    {

      return prev.id == -1 ? Edge(*this, u.id, v.id) : INVALID;

    }

    class Node {

      friend class FullGraphBase;

    protected:

      int id;

      Node(int _id) { id = _id;}

    public:

      Node() {}

      Node (Invalid) { id = -1; }

      bool operator==(const Node node) const {return id == node.id;}

      bool operator!=(const Node node) const {return id != node.id;}

      bool operator<(const Node node) const {return id < node.id;}

    };

    class Edge {

      friend class FullGraphBase;

    protected:

      int id;  // NodeNum * head + tail;

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

      Edge(const FullGraphBase& _graph, int tail, int head) 

	: id(_graph.NodeNum * head+tail) {}

    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;}

    };

    void first(Node& node) const {

      node.id = NodeNum-1;

    }

    static void next(Node& node) {

      --node.id;

    }

    void first(Edge& edge) const {

      edge.id = EdgeNum-1;

    }

    static void next(Edge& edge) {

      --edge.id;

    }

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

      edge.id = EdgeNum + node.id - NodeNum;

    }

    void nextOut(Edge& edge) const {

      edge.id -= NodeNum;

      if (edge.id < 0) edge.id = -1;

    }

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

      edge.id = node.id * NodeNum;

    }

    void nextIn(Edge& edge) const {

      ++edge.id;

      if (edge.id % NodeNum == 0) edge.id = -1;

    }

  };

  typedef AlterableGraphExtender<FullGraphBase> AlterableFullGraphBase;

  typedef IterableGraphExtender<AlterableFullGraphBase> IterableFullGraphBase;

  typedef IdMappableGraphExtender<IterableFullGraphBase> IdMappableFullGraphBase;

  typedef DefaultMappableGraphExtender<IdMappableFullGraphBase> MappableFullGraphBase;

  class FullGraph : public MappableFullGraphBase {

  public:

    FullGraph(int n) { construct(n); }

  };

  template <>

  int countNodes<FullGraph>(const FullGraph& graph) {

    return graph.nodeNum();

  }

  template <>

  int countEdges<FullGraph>(const FullGraph& graph) {

    return graph.edgeNum();

  }

  /// @}  

} //namespace lemon

#endif //LEMON_FULL_GRAPH_H