/* -*- 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_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