/* -*- mode: C++; indent-tabs-mode: nil; -*-

 *

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

 *

 * Copyright (C) 2003-2009

 * 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_CONCEPTS_DIGRAPH_H

#define LEMON_CONCEPTS_DIGRAPH_H

///\ingroup graph_concepts

///\file

///\brief The concept of directed graphs.

#include <lemon/core.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 common interface of all directed

    /// graphs (digraphs).

    ///

    /// Like all concept classes, it only provides an interface

    /// without any sensible implementation. So any general algorithm for

    /// directed graphs should compile with this class, but it will not

    /// run properly, of course.

    /// An actual digraph implementation like \ref ListDigraph or

    /// \ref SmartDigraph may have additional functionality.

    ///

    /// \sa Graph

    class Digraph {

    private:

      /// Diraphs are \e not copy constructible. Use DigraphCopy instead.

      Digraph(const Digraph &) {}

      /// \brief Assignment of a digraph to another one is \e not allowed.

      /// Use DigraphCopy instead.

      void operator=(const Digraph &) {}

    public:

      /// Default constructor.

      Digraph() { }

      /// The node type of the digraph

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

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

      /// thus they convert to this type.

      class Node {

      public:

        /// Default constructor

        /// Default constructor.

        /// \warning It sets the object to an undefined value.

        Node() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        Node(const Node&) { }

        /// %Invalid constructor \& conversion.

        /// Initializes the object to be invalid.

        /// \sa Invalid for more details.

        Node(Invalid) { }

        /// Equality operator

        /// Equality operator.

        ///

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

        /// same object or both are \c INVALID.

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

        /// Inequality operator

        /// Inequality operator.

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

        /// Artificial ordering operator.

        /// Artificial ordering operator.

        ///

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

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

        /// ordering of the nodes.

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

      };

      /// Iterator class for the nodes.

      /// This iterator goes through each node of the digraph.

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

      /// of nodes in a 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

        /// Default constructor.

        /// \warning It sets the iterator to an undefined value.

        NodeIt() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

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

        /// %Invalid constructor \& conversion.

        /// Initializes 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 the given digraph.

        ///

        explicit NodeIt(const Digraph&) { }

        /// Sets the iterator to the given node.

        /// Sets the iterator to the given node of the given digraph.

        ///

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

        /// Next node.

        /// Assign the iterator to the next node.

        ///

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

      };

      /// The arc type 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

        /// Default constructor.

        /// \warning It sets the object to an undefined value.

        Arc() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        Arc(const Arc&) { }

        /// %Invalid constructor \& conversion.

        /// Initializes the object to be invalid.

        /// \sa Invalid for more details.

        Arc(Invalid) { }

        /// Equality operator

        /// Equality operator.

        ///

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

        /// same object or both are \c INVALID.

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

        /// Inequality operator

        /// Inequality operator.

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

        /// Artificial ordering operator.

        /// Artificial ordering operator.

        ///

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

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

        /// ordering of the arcs.

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

      };

      /// Iterator class for 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 a digraph \c g of type \c %Digraph as follows.

      ///\code

      /// int count=0;

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

      ///\endcode

      class OutArcIt : public Arc {

      public:

        /// Default constructor

        /// Default constructor.

        /// \warning It sets the iterator to an undefined value.

        OutArcIt() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

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

        /// %Invalid constructor \& conversion.

        /// Initializes the iterator to be invalid.

        /// \sa Invalid for more details.

        OutArcIt(Invalid) { }

        /// Sets the iterator to the first outgoing arc.

        /// Sets the iterator to the first outgoing arc of the given node.

        ///

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

        /// Sets the iterator to the given arc.

        /// Sets the iterator to the given arc of the given digraph.

        ///

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

        /// Next outgoing arc

        /// Assign the iterator to the next

        /// outgoing arc of the corresponding node.

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

      };

      /// Iterator class for 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 incoming arcs of a node \c n

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

      ///\code

      /// int count=0;

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

      ///\endcode

      class InArcIt : public Arc {

      public:

        /// Default constructor

        /// Default constructor.

        /// \warning It sets the iterator to an undefined value.

        InArcIt() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

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

        /// %Invalid constructor \& conversion.

        /// Initializes the iterator to be invalid.

        /// \sa Invalid for more details.

        InArcIt(Invalid) { }

        /// Sets the iterator to the first incoming arc.

        /// Sets the iterator to the first incoming arc of the given node.

        ///

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

        /// Sets the iterator to the given arc.

        /// Sets the iterator to the given arc of the given digraph.

        ///

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

        /// Next incoming arc

        /// Assign the iterator to the next

        /// incoming arc of the corresponding node.

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

      };

      /// Iterator class for the arcs.

      /// This iterator goes through each arc of the 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 a(g); a!=INVALID; ++a) ++count;

      ///\endcode

      class ArcIt : public Arc {

      public:

        /// Default constructor

        /// Default constructor.

        /// \warning It sets the iterator to an undefined value.

        ArcIt() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

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

        /// %Invalid constructor \& conversion.

        /// Initializes the iterator to be invalid.

        /// \sa Invalid for more details.

        ArcIt(Invalid) { }

        /// Sets the iterator to the first arc.

        /// Sets the iterator to the first arc of the given digraph.

        ///

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

        /// Sets the iterator to the given arc.

        /// Sets the iterator to the given arc of the given digraph.

        ///

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

        /// Next arc

        /// Assign the iterator to the next arc.

        ///

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

      };

      /// \brief The source node of the arc.

      ///

      /// Returns the source node of the given arc.

      Node source(Arc) const { return INVALID; }

      /// \brief The target node of the arc.

      ///

      /// Returns the target node of the given arc.

      Node target(Arc) const { return INVALID; }

      /// \brief The ID of the node.

      ///

      /// Returns the ID of the given node.

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

      /// \brief The ID of the arc.

      ///

      /// Returns the ID of the given arc.

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

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

      ///

      /// Returns the node with the given ID.

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

      Node nodeFromId(int) const { return INVALID; }

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

      ///

      /// Returns the arc with the given ID.

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

      Arc arcFromId(int) const { return INVALID; }

      /// \brief An upper bound on the node IDs.

      ///

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

      int maxNodeId() const { return -1; }

      /// \brief An upper bound on the arc IDs.

      ///

      /// 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 opposite node on the arc.

      ///

      /// Returns the opposite node on the given arc.

      Node oppositeNode(Node, Arc) const { return INVALID; }

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

      ///

      /// Returns the base node of the given outgoing arc iterator

      /// (i.e. the source node of the corresponding arc).

      Node baseNode(OutArcIt) const { return INVALID; }

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

      ///

      /// Returns the running node of the given outgoing arc iterator

      /// (i.e. the target node of the corresponding arc).

      Node runningNode(OutArcIt) const { return INVALID; }

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

      ///

      /// Returns the base node of the given incomming arc iterator

      /// (i.e. the target node of the corresponding arc).

      Node baseNode(InArcIt) const { return INVALID; }

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

      ///

      /// Returns the running node of the given incomming arc iterator

      /// (i.e. the source node of the corresponding arc).

      Node runningNode(InArcIt) const { return INVALID; }

      /// \brief Standard graph map type for the nodes.

      ///

      /// Standard graph map type for the nodes.

      /// It conforms to the ReferenceMap concept.

      template<class T>

      class NodeMap : public ReferenceMap<Node, T, T&, const T&> {

      public:

        /// Constructor

        explicit NodeMap(const Digraph&) { }

        /// Constructor with given initial value

        NodeMap(const Digraph&, T) { }

      private:

        ///Copy constructor

        NodeMap(const NodeMap& nm) : 

          ReferenceMap<Node, T, T&, const T&>(nm) { }

        ///Assignment operator

        template <typename CMap>

        NodeMap& operator=(const CMap&) {

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

          return *this;

        }

      };

      /// \brief Standard graph map type for the arcs.

      ///

      /// Standard graph map type for the arcs.

      /// It conforms to the ReferenceMap concept.

      template<class T>

      class ArcMap : public ReferenceMap<Arc, T, T&, const T&> {

      public:

        /// Constructor

        explicit ArcMap(const Digraph&) { }

        /// Constructor with given initial value

        ArcMap(const Digraph&, T) { }

      private:

        ///Copy constructor

        ArcMap(const ArcMap& em) :

          ReferenceMap<Arc, T, T&, const T&>(em) { }

        ///Assignment operator

        template <typename CMap>

        ArcMap& operator=(const CMap&) {

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

          return *this;

        }

      };

      template <typename _Digraph>

      struct Constraints {

        void constraints() {

          checkConcept<BaseDigraphComponent, _Digraph>();

          checkConcept<IterableDigraphComponent<>, _Digraph>();

          checkConcept<IDableDigraphComponent<>, _Digraph>();

          checkConcept<MappableDigraphComponent<>, _Digraph>();

        }

      };

    };

  } //namespace concepts

} //namespace lemon

#endif