/* -*- 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_DIGRAPH_H

 #define LEMON_CONCEPT_DIGRAPH_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 digraphs.

     ///

     /// Note that actual digraph implementation like @ref ListDigraph or

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

     ///

     /// \sa concept

     class Digraph {

     private:

       ///Digraphs are \e not copy constructible. Use DigraphCopy() instead.

       ///Digraphs are \e not copy constructible. Use DigraphCopy() instead.

       ///

       Digraph(const Digraph &) {};

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

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

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

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

       void operator=(const Digraph &) {}

     public:

       ///\e

       /// Defalult constructor.

       /// Defalult constructor.

       ///

       Digraph() { }

       /// Class for identifying a node of the digraph

       /// This class identifies a node of the digraph. 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 digraph 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 digraph \c g of type \c Digraph like this:

       ///\code

       /// int count=0;

       /// for (Digraph::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 Digraph&) { }

         /// Node -> NodeIt conversion.

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

 	/// the trivial iterator.

         /// This feature necessitates that each time we 

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

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

         /// Next node.

         /// Assign the iterator to the next node.

         ///

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

       };

       /// Class for identifying an arc of the digraph

       /// This class identifies an arc of the digraph. It also serves

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

       /// thus they will convert to this type.

       class Arc {

       public:

         /// Default constructor

         /// @warning The default constructor sets the iterator

         /// to an undefined value.

         Arc() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

         Arc(const Arc&) { }

         /// Initialize the iterator to be invalid.

         /// Initialize the iterator to be invalid.

         ///

         Arc(Invalid) { }

         /// Equality operator

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

         /// same object or both are invalid.

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

         /// Inequality operator

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

         ///

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

 	/// Artificial ordering operator.

 	/// To allow the use of digraph 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<(Arc) const { return false; }

       };

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

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

       /// of a digraph.

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

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

       /// in digraph \c g of type \c Digraph as follows.

       ///\code

       /// int count=0;

       /// for (Digraph::OutArcIt e(g, n); e!=INVALID; ++e) ++count;

       ///\endcode

       class OutArcIt : public Arc {

       public:

         /// Default constructor

         /// @warning The default constructor sets the iterator

         /// to an undefined value.

         OutArcIt() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

         OutArcIt(const OutArcIt& e) : Arc(e) { }

         /// Initialize the iterator to be invalid.

         /// Initialize the iterator to be invalid.

         ///

         OutArcIt(Invalid) { }

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

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

         /// the node.

         OutArcIt(const Digraph&, const Node&) { }

         /// Arc -> OutArcIt conversion

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

 	/// This feature necessitates that each time we 

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

         OutArcIt(const Digraph&, const Arc&) { }

         ///Next outgoing arc

         /// Assign the iterator to the next 

         /// outgoing arc of the corresponding node.

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

       };

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

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

       /// of a digraph.

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

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

       /// in digraph \c g of type \c Digraph as follows.

       ///\code

       /// int count=0;

       /// for(Digraph::InArcIt e(g, n); e!=INVALID; ++e) ++count;

       ///\endcode

       class InArcIt : public Arc {

       public:

         /// Default constructor

         /// @warning The default constructor sets the iterator

         /// to an undefined value.

         InArcIt() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

         InArcIt(const InArcIt& e) : Arc(e) { }

         /// Initialize the iterator to be invalid.

         /// Initialize the iterator to be invalid.

         ///

         InArcIt(Invalid) { }

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

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

         /// the node.

         InArcIt(const Digraph&, const Node&) { }

         /// Arc -> InArcIt conversion

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

         /// This feature necessitates that each time we 

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

         InArcIt(const Digraph&, const Arc&) { }

         /// Next incoming arc

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

         ///

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

       };

       /// This iterator goes through each arc.

       /// This iterator goes through each arc of a digraph.

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

       /// of arcs in a digraph \c g of type \c Digraph as follows:

       ///\code

       /// int count=0;

       /// for(Digraph::ArcIt e(g); e!=INVALID; ++e) ++count;

       ///\endcode

       class ArcIt : public Arc {

       public:

         /// Default constructor

         /// @warning The default constructor sets the iterator

         /// to an undefined value.

         ArcIt() { }

         /// Copy constructor.

         /// Copy constructor.

         ///

         ArcIt(const ArcIt& e) : Arc(e) { }

         /// Initialize the iterator to be invalid.

         /// Initialize the iterator to be invalid.

         ///

         ArcIt(Invalid) { }

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

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

         ///@param g the digraph

         ArcIt(const Digraph& g) { ignore_unused_variable_warning(g); }

         /// Arc -> ArcIt conversion

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

         /// This feature necessitates that each time we 

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

         ArcIt(const Digraph&, const Arc&) { } 

         ///Next arc

         /// Assign the iterator to the next arc.

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

       };

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

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

       ///

       Node target(Arc) const { return INVALID; }

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

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

       ///

       Node source(Arc) const { return INVALID; }

       /// \brief Returns the ID of the node.

       int id(Node) const { return -1; } 

       /// \brief Returns the ID of the arc.

       int id(Arc) const { return -1; } 

       /// \brief Returns the node with the given ID.

       ///

       /// \pre The argument should be a valid node ID in the graph.

       Node nodeFromId(int) const { return INVALID; } 

       /// \brief Returns the arc with the given ID.

       ///

       /// \pre The argument should be a valid arc ID in the graph.

       Arc arcFromId(int) const { return INVALID; } 

       /// \brief Returns an upper bound on the node IDs.

       int maxNodeId() const { return -1; } 

       /// \brief Returns an upper bound on the arc IDs.

       int maxArcId() const { return -1; } 

       void first(Node&) const {}

       void next(Node&) const {}

       void first(Arc&) const {}

       void next(Arc&) const {}

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

       void nextIn(Arc&) const {}

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

       void nextOut(Arc&) const {}

       // The second parameter is dummy.

       Node fromId(int, Node) const { return INVALID; }

       // The second parameter is dummy.

       Arc fromId(int, Arc) const { return INVALID; }

       // Dummy parameter.

       int maxId(Node) const { return -1; } 

       // Dummy parameter.

       int maxId(Arc) const { return -1; } 

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

       ///

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

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

       Node baseNode(const InArcIt&) 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 arc.

       Node runningNode(const InArcIt&) 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 arc.

       Node baseNode(const OutArcIt&) 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 arc.

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

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

       ///

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

       Node oppositeNode(const Node&, const Arc&) 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 Digraph&) { }

         ///\e

         NodeMap(const Digraph&, 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 arcs to type \c T.

       ///

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

       /// \sa Reference

       template<class T> 

       class ArcMap : public ReadWriteMap<Arc,T> {

       public:

         ///\e

         ArcMap(const Digraph&) { }

         ///\e

         ArcMap(const Digraph&, T) { }

         ///Copy constructor

         ArcMap(const ArcMap& em) : ReadWriteMap<Arc,T>(em) { }

         ///Assignment operator

         template <typename CMap>

         ArcMap& operator=(const CMap&) { 

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

           return *this; 

         }

       };

       template <typename RDigraph>

       struct Constraints {

         void constraints() {

           checkConcept<IterableDigraphComponent<>, Digraph>();

 	  checkConcept<IDableDigraphComponent<>, Digraph>();

           checkConcept<MappableDigraphComponent<>, Digraph>();

         }

       };

     };

   } //namespace concepts  

 } //namespace lemon

 #endif // LEMON_CONCEPT_DIGRAPH_H