/* -*- C++ -*-

  * src/lemon/skeletons/graph.h - Part of LEMON, a generic C++ optimization library

  *

  * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

  * (Egervary Combinatorial Optimization Research Group, 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_SKELETON_GRAPH_H

 #define LEMON_SKELETON_GRAPH_H

 ///\ingroup skeletons

 ///\file

 ///\brief Declaration of Graph.

 #include <lemon/invalid.h>

 #include <lemon/skeletons/maps.h>

 namespace lemon {

   namespace skeleton {

     /// \addtogroup skeletons

     /// @{

     /// An empty static graph class.

     /// This class provides all the common features of a graph structure,

     /// however completely without implementations and real data structures

     /// behind the interface.

     /// All graph algorithms should compile with this class, but it will not

     /// run properly, of course.

     ///

     /// It can be used for checking the interface compatibility,

     /// or it can serve as a skeleton of a new graph structure.

     /// 

     /// Also, you will find here the full documentation of a certain graph

     /// feature, the documentation of a real graph imlementation

     /// like @ref ListGraph or

     /// @ref SmartGraph will just refer to this structure.

     ///

     /// \todo A pages describing the concept of concept description would

     /// be nice.

     class StaticGraph

     {

     public:

       /// Defalult constructor.

       /// Defalult constructor.

       ///

       StaticGraph() { }

       ///Copy consructor.

 //       ///\todo It is not clear, what we expect from a copy constructor.

 //       ///E.g. How to assign the nodes/edges to each other? What about maps?

 //       StaticGraph(const StaticGraph& g) { }

       /// The base type of node iterators, 

       /// or in other words, the trivial node iterator.

       /// This is the base type of each node iterator,

       /// thus each kind of node iterator converts to this.

       /// More precisely each kind of node iterator should be inherited 

       /// from the trivial node iterator.

       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; }

  	///Comparison operator.

 	///This is a strict ordering between the nodes.

 	///

 	///This ordering can be different from the order in which NodeIt

 	///goes through the nodes.

 	///\todo Possibly we don't need it.

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

       };

       /// 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&) { }

 	/// 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 StaticGraph& g) { }

 	/// Node -> NodeIt conversion.

 	/// Sets the iterator to the node of \c g pointed by the trivial 

 	/// iterator n.

 	/// This feature necessitates that each time we 

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

 	NodeIt(const StaticGraph& g, const Node& n) { }

 	/// Next node.

 	/// Assign the iterator to the next node.

 	///

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

       };

       /// The base type of the edge iterators.

       /// The base type of the edge iterators.

       ///

       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==(Node n)

 	///

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

  	///Comparison operator.

 	///This is a strict ordering between the nodes.

 	///

 	///This ordering can be different from the order in which NodeIt

 	///goes through the nodes.

 	///\todo Possibly we don't need it.

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

       };

       /// 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&) { }

 	/// Initialize the iterator to be invalid.

 	/// Initialize the iterator to be invalid.

 	///

 	OutEdgeIt(Invalid) { }

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

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

 	/// node

 	///@param n the node

 	///@param g the graph

 	OutEdgeIt(const StaticGraph& g, const Node& n) { }

 	/// Edge -> OutEdgeIt 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.

 	OutEdgeIt(const StaticGraph& g, const Edge& e) { }

 	///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&) { }

 	/// 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

 	/// node

 	///@param n the node

 	///@param g the graph

 	InEdgeIt(const StaticGraph& g, const Node& n) { }

 	/// 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 StaticGraph& g, const Edge& n) { }

 	/// 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&) { }

 	/// Initialize the iterator to be invalid.

 	/// Initialize the iterator to be invalid.

 	///

 	EdgeIt(Invalid) { }

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

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

 	/// node

 	///@param g the graph

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

     	///Next edge

 	/// Assign the iterator to the next 

 	/// edge of the corresponding node.

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

       };

       /// First node of the graph.

       /// \retval i the first node.

       /// \return the first node.

       ///

       NodeIt& first(NodeIt& i) const { return i; }

       /// The first incoming edge.

       /// The first incoming edge.

       ///

       InEdgeIt& first(InEdgeIt &i, Node) const { return i; }

       /// The first outgoing edge.

       /// The first outgoing edge.

       ///

       OutEdgeIt& first(OutEdgeIt& i, Node) const { return i; }

       /// The first edge of the Graph.

       /// The first edge of the Graph.

       ///

       EdgeIt& first(EdgeIt& i) const { return i; }

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

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

       ///

       Node head(Edge) const { return INVALID; }

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

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

       ///

       Node tail(Edge) const { return INVALID; }

       ///Gives back the \e id of a node.

       ///\warning Not all graph structures provide this feature.

       ///

       ///\todo Should each graph provide \c id?

       int id(const Node&) const { return 0; }

       ///Gives back the \e id of an edge.

       ///\warning Not all graph structures provide this feature.

       ///

       ///\todo Should each graph provide \c id?

       int id(const Edge&) const { return 0; }

       ///\e

       ///\todo Should it be in the concept?

       ///

       int nodeNum() const { return 0; }

       ///\e

       ///\todo Should it be in the concept?

       ///

       int edgeNum() const { return 0; }

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

       /// \ingroup skeletons

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

       /// \sa Reference

       /// \warning Making maps that can handle bool type (NodeMap<bool>)

       /// needs some extra attention!

       template<class T> class NodeMap : public ReferenceMap< Node, T >

       {

       public:

 	///\e

 	NodeMap(const StaticGraph&) { }

 	///\e

 	NodeMap(const StaticGraph&, T) { }

 	///Copy constructor

 	template<typename TT> NodeMap(const NodeMap<TT>&) { }

 	///Assignment operator

 	template<typename TT> NodeMap& operator=(const NodeMap<TT>&)

 	{ return *this; }

       };

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

       /// \ingroup skeletons

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

       /// \sa Reference

       /// \warning Making maps that can handle bool type (EdgeMap<bool>)

       /// needs some extra attention!

       template<class T> class EdgeMap

 	: public ReferenceMap<Edge,T>

       {

       public:

 	///\e

 	EdgeMap(const StaticGraph&) { }

 	///\e

 	EdgeMap(const StaticGraph&, T) { }

 	///Copy constructor

 	template<typename TT> EdgeMap(const EdgeMap<TT>&) { }

 	///Assignment operator

 	template<typename TT> EdgeMap &operator=(const EdgeMap<TT>&)

 	{ return *this; }

       };

     };

     struct DummyType {

       int value;

       DummyType() {}

       DummyType(int p) : value(p) {}

       DummyType& operator=(int p) { value = p; return *this;}

     };

     ///\brief Checks whether \c G meets the

     ///\ref lemon::skeleton::StaticGraph "StaticGraph" concept

     template<class Graph> void checkCompileStaticGraph(Graph &G) 

     {

       typedef typename Graph::Node Node;

       typedef typename Graph::NodeIt NodeIt;

       typedef typename Graph::Edge Edge;

       typedef typename Graph::EdgeIt EdgeIt;

       typedef typename Graph::InEdgeIt InEdgeIt;

       typedef typename Graph::OutEdgeIt OutEdgeIt;

       {

 	Node i; Node j(i); Node k(INVALID);

 	i=j;

 	bool b; b=true;

 	b=(i==INVALID); b=(i!=INVALID);

 	b=(i==j); b=(i!=j); b=(i<j);

       }

       {

 	NodeIt i; NodeIt j(i); NodeIt k(INVALID); NodeIt l(G);

 	i=j;

 	j=G.first(i);

 	j=++i;

 	bool b; b=true;

 	b=(i==INVALID); b=(i!=INVALID);

 	Node n(i);

 	n=i;

 	b=(i==j); b=(i!=j); b=(i<j);

 	//Node ->NodeIt conversion

 	NodeIt ni(G,n);

       }

       {

 	Edge i; Edge j(i); Edge k(INVALID);

 	i=j;

 	bool b; b=true;

 	b=(i==INVALID); b=(i!=INVALID);

 	b=(i==j); b=(i!=j); b=(i<j);

       }

       {

 	EdgeIt i; EdgeIt j(i); EdgeIt k(INVALID); EdgeIt l(G);

 	i=j;

 	j=G.first(i);

 	j=++i;

 	bool b; b=true;

 	b=(i==INVALID); b=(i!=INVALID);

 	Edge e(i);

 	e=i;

 	b=(i==j); b=(i!=j); b=(i<j);

 	//Edge ->EdgeIt conversion

 	EdgeIt ei(G,e);

       }

       {

 	Node n;

 	InEdgeIt i; InEdgeIt j(i); InEdgeIt k(INVALID); InEdgeIt l(G,n);

 	i=j;

 	j=G.first(i,n);

 	j=++i;

 	bool b; b=true;

 	b=(i==INVALID); b=(i!=INVALID);

 	Edge e(i);

 	e=i;

 	b=(i==j); b=(i!=j); b=(i<j);

 	//Edge ->InEdgeIt conversion

 	InEdgeIt ei(G,e);

       }

       {

 	Node n;

 	OutEdgeIt i; OutEdgeIt j(i); OutEdgeIt k(INVALID); OutEdgeIt l(G,n);

 	i=j;

 	j=G.first(i,n);

 	j=++i;

 	bool b; b=true;

 	b=(i==INVALID); b=(i!=INVALID);

 	Edge e(i);

 	e=i;

 	b=(i==j); b=(i!=j); b=(i<j);

 	//Edge ->OutEdgeIt conversion

 	OutEdgeIt ei(G,e);

       }

       {

 	Node n,m;

 	n=m=INVALID;

 	Edge e;

 	e=INVALID;

 	n=G.tail(e);

 	n=G.head(e);

       }

       // id tests

       { Node n; int i=G.id(n); i=i; }

       { Edge e; int i=G.id(e); i=i; }

       //NodeMap tests

       {

 	Node k;

 	typename Graph::template NodeMap<int> m(G);

 	//Const map

 	typename Graph::template NodeMap<int> const &cm = m;

 	//Inicialize with default value

 	typename Graph::template NodeMap<int> mdef(G,12);

 	//Copy

 	typename Graph::template NodeMap<int> mm(cm);

 	//Copy from another type

 	typename Graph::template NodeMap<double> dm(cm);

 	//Copy to more complex type

 	typename Graph::template NodeMap<DummyType> em(cm);

 	int v;

 	v=m[k]; m[k]=v; m.set(k,v);

 	v=cm[k];

 	m=cm;  

 	dm=cm; //Copy from another type  

 	em=cm; //Copy to more complex type

 	{

 	  //Check the typedef's

 	  typename Graph::template NodeMap<int>::ValueType val;

 	  val=1;

 	  typename Graph::template NodeMap<int>::KeyType key;

 	  key = typename Graph::NodeIt(G);

 	}

       }  

       { //bool NodeMap

 	Node k;

 	typename Graph::template NodeMap<bool> m(G);

 	typename Graph::template NodeMap<bool> const &cm = m;  //Const map

 	//Inicialize with default value

 	typename Graph::template NodeMap<bool> mdef(G,12);

 	typename Graph::template NodeMap<bool> mm(cm);   //Copy

 	typename Graph::template NodeMap<int> dm(cm); //Copy from another type

 	bool v;

 	v=m[k]; m[k]=v; m.set(k,v);

 	v=cm[k];

 	m=cm;  

 	dm=cm; //Copy from another type

 	m=dm; //Copy to another type

 	{

 	  //Check the typedef's

 	  typename Graph::template NodeMap<bool>::ValueType val;

 	  val=true;

 	  typename Graph::template NodeMap<bool>::KeyType key;

 	  key= typename Graph::NodeIt(G);

 	}

       }

       //EdgeMap tests

       {

 	Edge k;

 	typename Graph::template EdgeMap<int> m(G);

 	typename Graph::template EdgeMap<int> const &cm = m;  //Const map

 	//Inicialize with default value

 	typename Graph::template EdgeMap<int> mdef(G,12);

 	typename Graph::template EdgeMap<int> mm(cm);   //Copy

 	typename Graph::template EdgeMap<double> dm(cm);//Copy from another type

 	int v;

 	v=m[k]; m[k]=v; m.set(k,v);

 	v=cm[k];

 	m=cm;  

 	dm=cm; //Copy from another type

 	{

 	  //Check the typedef's

 	  typename Graph::template EdgeMap<int>::ValueType val;

 	  val=1;

 	  typename Graph::template EdgeMap<int>::KeyType key;

 	  key= typename Graph::EdgeIt(G);

 	}

       }  

       { //bool EdgeMap

 	Edge k;

 	typename Graph::template EdgeMap<bool> m(G);

 	typename Graph::template EdgeMap<bool> const &cm = m;  //Const map

 	//Inicialize with default value

 	typename Graph::template EdgeMap<bool> mdef(G,12);

 	typename Graph::template EdgeMap<bool> mm(cm);   //Copy

 	typename Graph::template EdgeMap<int> dm(cm); //Copy from another type

 	bool v;

 	v=m[k]; m[k]=v; m.set(k,v);

 	v=cm[k];

 	m=cm;  

 	dm=cm; //Copy from another type

 	m=dm; //Copy to another type

 	{

 	  //Check the typedef's

 	  typename Graph::template EdgeMap<bool>::ValueType val;

 	  val=true;

 	  typename Graph::template EdgeMap<bool>::KeyType key;

 	  key= typename Graph::EdgeIt(G);

 	}

       }

     }

     /// An empty non-static graph class.

     /// This class provides everything that \ref StaticGraph

     /// with additional functionality which enables to build a

     /// graph from scratch.

     class ExtendableGraph : public StaticGraph

     {

     public:

       /// Defalult constructor.

       /// Defalult constructor.

       ///

       ExtendableGraph() { }

       ///Add a new node to the graph.

       /// \return the new node.

       ///

       Node addNode() { return INVALID; }

       ///Add a new edge to the graph.

       ///Add a new edge to the graph with tail node \c t

       ///and head node \c h.

       ///\return the new edge.

       Edge addEdge(Node h, Node t) { return INVALID; }

       /// Resets the graph.

       /// This function deletes all edges and nodes of the graph.

       /// It also frees the memory allocated to store them.

       /// \todo It might belong to \ref ErasableGraph.

       void clear() { }

     };

     ///\brief Checks whether \c G meets the

     ///\ref lemon::skeleton::ExtendableGraph "ExtendableGraph" concept

     template<class Graph> void checkCompileExtendableGraph(Graph &G) 

     {

       checkCompileStaticGraph(G);

       typedef typename Graph::Node Node;

       typedef typename Graph::NodeIt NodeIt;

       typedef typename Graph::Edge Edge;

       typedef typename Graph::EdgeIt EdgeIt;

       typedef typename Graph::InEdgeIt InEdgeIt;

       typedef typename Graph::OutEdgeIt OutEdgeIt;

       Node n,m;

       n=G.addNode();

       m=G.addNode();

       Edge e;

       e=G.addEdge(n,m); 

       //  G.clear();

     }

     /// An empty erasable graph class.

     /// This class is an extension of \ref ExtendableGraph. It also makes it

     /// possible to erase edges or nodes.

     class ErasableGraph : public ExtendableGraph

     {

     public:

       /// Defalult constructor.

       /// Defalult constructor.

       ///

       ErasableGraph() { }

       /// Deletes a node.

       /// Deletes node \c n node.

       ///

       void erase(Node n) { }

       /// Deletes an edge.

       /// Deletes edge \c e edge.

       ///

       void erase(Edge e) { }

     };

     template<class Graph> void checkCompileGraphEraseEdge(Graph &G) 

     {

       typename Graph::Edge e;

       G.erase(e);

     }

     template<class Graph> void checkCompileGraphEraseNode(Graph &G) 

     {

       typename Graph::Node n;

       G.erase(n);

     }

     ///\brief Checks whether \c G meets the

     ///\ref lemon::skeleton::EresableGraph "EresableGraph" concept

     template<class Graph> void checkCompileErasableGraph(Graph &G) 

     {

       checkCompileExtendableGraph(G);

       checkCompileGraphEraseNode(G);

       checkCompileGraphEraseEdge(G);

     }

     ///Checks whether a graph has findEdge() member function.

     ///\todo findEdge() might be a global function.

     ///

     template<class Graph> void checkCompileGraphFindEdge(Graph &G) 

     {

       typedef typename Graph::NodeIt Node;

       typedef typename Graph::NodeIt NodeIt;

       G.findEdge(NodeIt(G),++NodeIt(G),G.findEdge(NodeIt(G),++NodeIt(G)));

       G.findEdge(Node(),Node(),G.findEdge(Node(),Node()));  

     }

     // @}

   } //namespace skeleton  

 } //namespace lemon

 #endif // LEMON_SKELETON_GRAPH_H