/* -*- C++ -*-

  *

  * This file is a part of LEMON, a generic C++ optimization library

  *

  * Copyright (C) 2003-2008

  * 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_CONCEPT_GRAPH_H

 #define LEMON_CONCEPT_GRAPH_H

 ///\ingroup graph_concepts

 ///\file

 ///\brief The concept of Directed Graphs.

 #include <lemon/bits/invalid.h>

 #include <lemon/bits/utility.h>

 #include <lemon/concepts/maps.h>

 #include <lemon/concept_check.h>

 #include <lemon/concepts/graph_components.h>

 namespace lemon {

   namespace concepts {

     /// \ingroup graph_concepts

     ///

     /// \brief Class describing the concept of Directed Graphs.

     ///

     /// This class describes the \ref concept "concept" of the

     /// immutable directed graphs.

     ///

     /// Note that actual graph implementation like @ref ListGraph or

     /// @ref SmartGraph may have several additional functionality.

     ///

     /// \sa concept

     class Graph {

     private:

       ///Graphs are \e not copy constructible. Use GraphCopy() instead.

       ///Graphs are \e not copy constructible. Use GraphCopy() instead.

       ///

       Graph(const Graph &) {};

       ///\brief Assignment of \ref Graph "Graph"s to another ones are

       ///\e not allowed. Use GraphCopy() instead.

       ///Assignment of \ref Graph "Graph"s to another ones are

       ///\e not allowed.  Use GraphCopy() instead.

       void operator=(const Graph &) {}

     public:

       ///\e

       /// Defalult constructor.

       /// Defalult constructor.

       ///

       Graph() { }

       /// Class for identifying a node of the graph

       /// This class identifies a node of the graph. It also serves

       /// as a base class of the node iterators,

       /// thus they will convert to this type.

       class Node {

       public:

         /// Default constructor

         /// @warning The default constructor sets the iterator

         /// to an undefined value.

         Node() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

         Node(const Node&) { }

         /// Invalid constructor \& conversion.

         /// This constructor initializes the iterator to be invalid.

         /// \sa Invalid for more details.

         Node(Invalid) { }

         /// Equality operator

         /// Two iterators are equal if and only if they point to the

         /// same object or both are invalid.

         bool operator==(Node) const { return true; }

         /// Inequality operator

         /// \sa operator==(Node n)

         ///

         bool operator!=(Node) const { return true; }

 	/// Artificial ordering operator.

 	/// To allow the use of graph descriptors as key type in std::map or

 	/// similar associative container we require this.

 	///

 	/// \note This operator only have to define some strict ordering of

 	/// the items; this order has nothing to do with the iteration

 	/// ordering of the items.

 	bool operator<(Node) const { return false; }

       };

       /// This iterator goes through each node.

       /// This iterator goes through each node.

       /// Its usage is quite simple, for example you can count the number

       /// of nodes in graph \c g of type \c Graph like this:

       ///\code

       /// int count=0;

       /// for (Graph::NodeIt n(g); n!=INVALID; ++n) ++count;

       ///\endcode

       class NodeIt : public Node {

       public:

         /// Default constructor

         /// @warning The default constructor sets the iterator

         /// to an undefined value.

         NodeIt() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

         NodeIt(const NodeIt& n) : Node(n) { }

         /// Invalid constructor \& conversion.

         /// Initialize the iterator to be invalid.

         /// \sa Invalid for more details.

         NodeIt(Invalid) { }

         /// Sets the iterator to the first node.

         /// Sets the iterator to the first node of \c g.

         ///

         NodeIt(const Graph&) { }

         /// Node -> NodeIt conversion.

         /// Sets the iterator to the node of \c the graph pointed by 

 	/// the trivial iterator.

         /// This feature necessitates that each time we 

         /// iterate the edge-set, the iteration order is the same.

         NodeIt(const Graph&, const Node&) { }

         /// Next node.

         /// Assign the iterator to the next node.

         ///

         NodeIt& operator++() { return *this; }

       };

       /// Class for identifying an edge of the graph

       /// This class identifies an edge of the graph. It also serves

       /// as a base class of the edge iterators,

       /// thus they will convert to this type.

       class Edge {

       public:

         /// Default constructor

         /// @warning The default constructor sets the iterator

         /// to an undefined value.

         Edge() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

         Edge(const Edge&) { }

         /// Initialize the iterator to be invalid.

         /// Initialize the iterator to be invalid.

         ///

         Edge(Invalid) { }

         /// Equality operator

         /// Two iterators are equal if and only if they point to the

         /// same object or both are invalid.

         bool operator==(Edge) const { return true; }

         /// Inequality operator

         /// \sa operator==(Edge n)

         ///

         bool operator!=(Edge) const { return true; }

 	/// Artificial ordering operator.

 	/// To allow the use of graph descriptors as key type in std::map or

 	/// similar associative container we require this.

 	///

 	/// \note This operator only have to define some strict ordering of

 	/// the items; this order has nothing to do with the iteration

 	/// ordering of the items.

 	bool operator<(Edge) const { return false; }

       };

       /// This iterator goes trough the outgoing edges of a node.

       /// This iterator goes trough the \e outgoing edges of a certain node

       /// of a graph.

       /// Its usage is quite simple, for example you can count the number

       /// of outgoing edges of a node \c n

       /// in graph \c g of type \c Graph as follows.

       ///\code

       /// int count=0;

       /// for (Graph::OutEdgeIt e(g, n); e!=INVALID; ++e) ++count;

       ///\endcode

       class OutEdgeIt : public Edge {

       public:

         /// Default constructor

         /// @warning The default constructor sets the iterator

         /// to an undefined value.

         OutEdgeIt() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

         OutEdgeIt(const OutEdgeIt& e) : Edge(e) { }

         /// Initialize the iterator to be invalid.

         /// Initialize the iterator to be invalid.

         ///

         OutEdgeIt(Invalid) { }

         /// This constructor sets the iterator to the first outgoing edge.

         /// This constructor sets the iterator to the first outgoing edge of

         /// the node.

         OutEdgeIt(const Graph&, const Node&) { }

         /// Edge -> OutEdgeIt conversion

         /// Sets the iterator to the value of the trivial iterator.

 	/// This feature necessitates that each time we 

         /// iterate the edge-set, the iteration order is the same.

         OutEdgeIt(const Graph&, const Edge&) { }

         ///Next outgoing edge

         /// Assign the iterator to the next 

         /// outgoing edge of the corresponding node.

         OutEdgeIt& operator++() { return *this; }

       };

       /// This iterator goes trough the incoming edges of a node.

       /// This iterator goes trough the \e incoming edges of a certain node

       /// of a graph.

       /// Its usage is quite simple, for example you can count the number

       /// of outgoing edges of a node \c n

       /// in graph \c g of type \c Graph as follows.

       ///\code

       /// int count=0;

       /// for(Graph::InEdgeIt e(g, n); e!=INVALID; ++e) ++count;

       ///\endcode

       class InEdgeIt : public Edge {

       public:

         /// Default constructor

         /// @warning The default constructor sets the iterator

         /// to an undefined value.

         InEdgeIt() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

         InEdgeIt(const InEdgeIt& e) : Edge(e) { }

         /// Initialize the iterator to be invalid.

         /// Initialize the iterator to be invalid.

         ///

         InEdgeIt(Invalid) { }

         /// This constructor sets the iterator to first incoming edge.

         /// This constructor set the iterator to the first incoming edge of

         /// the node.

         InEdgeIt(const Graph&, const Node&) { }

         /// Edge -> InEdgeIt conversion

         /// Sets the iterator to the value of the trivial iterator \c e.

         /// This feature necessitates that each time we 

         /// iterate the edge-set, the iteration order is the same.

         InEdgeIt(const Graph&, const Edge&) { }

         /// Next incoming edge

         /// Assign the iterator to the next inedge of the corresponding node.

         ///

         InEdgeIt& operator++() { return *this; }

       };

       /// This iterator goes through each edge.

       /// This iterator goes through each edge of a graph.

       /// Its usage is quite simple, for example you can count the number

       /// of edges in a graph \c g of type \c Graph as follows:

       ///\code

       /// int count=0;

       /// for(Graph::EdgeIt e(g); e!=INVALID; ++e) ++count;

       ///\endcode

       class EdgeIt : public Edge {

       public:

         /// Default constructor

         /// @warning The default constructor sets the iterator

         /// to an undefined value.

         EdgeIt() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

         EdgeIt(const EdgeIt& e) : Edge(e) { }

         /// Initialize the iterator to be invalid.

         /// Initialize the iterator to be invalid.

         ///

         EdgeIt(Invalid) { }

         /// This constructor sets the iterator to the first edge.

         /// This constructor sets the iterator to the first edge of \c g.

         ///@param g the graph

         EdgeIt(const Graph& g) { ignore_unused_variable_warning(g); }

         /// Edge -> EdgeIt conversion

         /// Sets the iterator to the value of the trivial iterator \c e.

         /// This feature necessitates that each time we 

         /// iterate the edge-set, the iteration order is the same.

         EdgeIt(const Graph&, const Edge&) { } 

         ///Next edge

         /// Assign the iterator to the next edge.

         EdgeIt& operator++() { return *this; }

       };

       ///Gives back the target node of an edge.

       ///Gives back the target node of an edge.

       ///

       Node target(Edge) const { return INVALID; }

       ///Gives back the source node of an edge.

       ///Gives back the source node of an edge.

       ///

       Node source(Edge) const { return INVALID; }

       void first(Node&) const {}

       void next(Node&) const {}

       void first(Edge&) const {}

       void next(Edge&) const {}

       void firstIn(Edge&, const Node&) const {}

       void nextIn(Edge&) const {}

       void firstOut(Edge&, const Node&) const {}

       void nextOut(Edge&) const {}

       /// \brief The base node of the iterator.

       ///

       /// Gives back the base node of the iterator.

       /// It is always the target of the pointed edge.

       Node baseNode(const InEdgeIt&) const { return INVALID; }

       /// \brief The running node of the iterator.

       ///

       /// Gives back the running node of the iterator.

       /// It is always the source of the pointed edge.

       Node runningNode(const InEdgeIt&) const { return INVALID; }

       /// \brief The base node of the iterator.

       ///

       /// Gives back the base node of the iterator.

       /// It is always the source of the pointed edge.

       Node baseNode(const OutEdgeIt&) const { return INVALID; }

       /// \brief The running node of the iterator.

       ///

       /// Gives back the running node of the iterator.

       /// It is always the target of the pointed edge.

       Node runningNode(const OutEdgeIt&) const { return INVALID; }

       /// \brief The opposite node on the given edge.

       ///

       /// Gives back the opposite node on the given edge.

       Node oppositeNode(const Node&, const Edge&) const { return INVALID; }

       /// \brief Read write map of the nodes to type \c T.

       /// 

       /// ReadWrite map of the nodes to type \c T.

       /// \sa Reference

       template<class T> 

       class NodeMap : public ReadWriteMap< Node, T > {

       public:

         ///\e

         NodeMap(const Graph&) { }

         ///\e

         NodeMap(const Graph&, T) { }

         ///Copy constructor

         NodeMap(const NodeMap& nm) : ReadWriteMap< Node, T >(nm) { }

         ///Assignment operator

         template <typename CMap>

         NodeMap& operator=(const CMap&) { 

           checkConcept<ReadMap<Node, T>, CMap>();

           return *this; 

         }

       };

       /// \brief Read write map of the edges to type \c T.

       ///

       /// Reference map of the edges to type \c T.

       /// \sa Reference

       template<class T> 

       class EdgeMap : public ReadWriteMap<Edge,T> {

       public:

         ///\e

         EdgeMap(const Graph&) { }

         ///\e

         EdgeMap(const Graph&, T) { }

         ///Copy constructor

         EdgeMap(const EdgeMap& em) : ReadWriteMap<Edge,T>(em) { }

         ///Assignment operator

         template <typename CMap>

         EdgeMap& operator=(const CMap&) { 

           checkConcept<ReadMap<Edge, T>, CMap>();

           return *this; 

         }

       };

       template <typename RGraph>

       struct Constraints {

         void constraints() {

           checkConcept<IterableGraphComponent<>, Graph>();

           checkConcept<MappableGraphComponent<>, Graph>();

         }

       };

     };

   } //namespace concepts  

 } //namespace lemon

 #endif // LEMON_CONCEPT_GRAPH_H