/* -*- C++ -*-

 *

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

 *

 * Copyright (C) 2003-2007

 * 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