// -*- mode:C++ -*-

 #ifndef HUGO_SMART_GRAPH_H

 #define HUGO_SMART_GRAPH_H

 ///\ingroup graphs

 ///\file

 ///\brief SmartGraph and SymSmartGraph classes.

 #include <vector>

 #include <limits.h>

 #include <hugo/invalid.h>

 namespace hugo {

 /// \addtogroup graphs

 /// @{

   class SymSmartGraph;

   ///A smart graph class.

   ///This is a simple and fast graph implementation.

   ///It is also quite memory efficient, but at the price

   ///that <b> it does not support node and edge deletion</b>.

   ///It conforms to the graph interface documented under

   ///the description of \ref GraphSkeleton.

   ///\sa \ref GraphSkeleton.

   ///

   ///\todo Some member functions could be \c static.

   ///

   ///\todo A possibly useful functionality: a function saveState() would

   ///give back a data sturcture X and then the function restoreState(X)

   ///would remove the nodes and edges added after the call of saveState().

   ///Of course it should be used as a stack. (Maybe X is not necessary.)

   ///

   ///\author Alpar Juttner

   class SmartGraph {

     struct NodeT 

     {

       int first_in,first_out;      

       NodeT() : first_in(-1), first_out(-1) {}

     };

     struct EdgeT 

     {

       int head, tail, next_in, next_out;      

       //FIXME: is this necessary?

       EdgeT() : next_in(-1), next_out(-1) {}  

     };

     std::vector<NodeT> nodes;

     std::vector<EdgeT> edges;

     protected:

     template <typename Key> class DynMapBase

     {

     protected:

       const SmartGraph* G; 

     public:

       virtual void add(const Key k) = 0;

       virtual void erase(const Key k) = 0;

       DynMapBase(const SmartGraph &_G) : G(&_G) {}

       virtual ~DynMapBase() {}

       friend class SmartGraph;

     };

   public:

     template <typename T> class EdgeMap;

     template <typename T> class NodeMap;

     class Node;

     class Edge;

     //  protected:

     // HELPME:

   protected:

     ///\bug It must be public because of SymEdgeMap.

     ///

     mutable std::vector<DynMapBase<Node> * > dyn_node_maps;

     ///\bug It must be public because of SymEdgeMap.

     ///

     mutable std::vector<DynMapBase<Edge> * > dyn_edge_maps;

   public:

     class NodeIt;

     class EdgeIt;

     class OutEdgeIt;

     class InEdgeIt;

     template <typename T> class NodeMap;

     template <typename T> class EdgeMap;

   public:

     SmartGraph() : nodes(), edges() { }

     SmartGraph(const SmartGraph &_g) : nodes(_g.nodes), edges(_g.edges) { }

     ~SmartGraph()

     {

       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();

 	  i!=dyn_node_maps.end(); ++i) (**i).G=NULL;

       for(std::vector<DynMapBase<Edge> * >::iterator i=dyn_edge_maps.begin();

 	  i!=dyn_edge_maps.end(); ++i) (**i).G=NULL;

     }

     int nodeNum() const { return nodes.size(); }  //FIXME: What is this?

     int edgeNum() const { return edges.size(); }  //FIXME: What is this?

     ///\bug This function does something different than

     ///its name would suggests...

     int maxNodeId() const { return nodes.size(); }  //FIXME: What is this?

     ///\bug This function does something different than

     ///its name would suggests...

     int maxEdgeId() const { return edges.size(); }  //FIXME: What is this?

     Node tail(Edge e) const { return edges[e.n].tail; }

     Node head(Edge e) const { return edges[e.n].head; }

     NodeIt& first(NodeIt& v) const { 

       v=NodeIt(*this); return v; }

     EdgeIt& first(EdgeIt& e) const { 

       e=EdgeIt(*this); return e; }

     OutEdgeIt& first(OutEdgeIt& e, const Node v) const { 

       e=OutEdgeIt(*this,v); return e; }

     InEdgeIt& first(InEdgeIt& e, const Node v) const { 

       e=InEdgeIt(*this,v); return e; }

     static int id(Node v) { return v.n; }

     static int id(Edge e) { return e.n; }

     Node addNode() {

       Node n; n.n=nodes.size();

       nodes.push_back(NodeT()); //FIXME: Hmmm...

       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();

 	  i!=dyn_node_maps.end(); ++i) (**i).add(n);

       return n;

     }

     Edge addEdge(Node u, Node v) {

       Edge e; e.n=edges.size(); edges.push_back(EdgeT()); //FIXME: Hmmm...

       edges[e.n].tail=u.n; edges[e.n].head=v.n;

       edges[e.n].next_out=nodes[u.n].first_out;

       edges[e.n].next_in=nodes[v.n].first_in;

       nodes[u.n].first_out=nodes[v.n].first_in=e.n;

       for(std::vector<DynMapBase<Edge> * >::iterator i=dyn_edge_maps.begin();

 	  i!=dyn_edge_maps.end(); ++i) (**i).add(e);

       return e;

     }

     /// Finds an edge between two nodes.

     /// Finds an edge from node \c u to node \c v.

     ///

     /// If \c prev is \ref INVALID (this is the default value), then

     /// It finds the first edge from \c u to \c v. Otherwise it looks for

     /// the next edge from \c u to \c v after \c prev.

     /// \return The found edge or INVALID if there is no such an edge.

     Edge findEdge(Node u,Node v, Edge prev = INVALID) 

     {

       int e = (prev.n==-1)? nodes[u.n].first_out : edges[prev.n].next_out;

       while(e!=-1 && edges[e].tail!=v.n) e = edges[e].next_out;

       prev.n=e;

       return prev;

     }

     void clear() {nodes.clear();edges.clear();}

     class Node {

       friend class SmartGraph;

       template <typename T> friend class NodeMap;

       friend class Edge;

       friend class OutEdgeIt;

       friend class InEdgeIt;

       friend class SymEdge;

     protected:

       int n;

       friend int SmartGraph::id(Node v); 

       Node(int nn) {n=nn;}

     public:

       Node() {}

       Node (Invalid) { n=-1; }

       bool operator==(const Node i) const {return n==i.n;}

       bool operator!=(const Node i) const {return n!=i.n;}

       bool operator<(const Node i) const {return n<i.n;}

       //      ///Validity check

       //      operator bool() { return n!=-1; }

     };

     class NodeIt : public Node {

       const SmartGraph *G;

       friend class SmartGraph;

     public:

       NodeIt() : Node() { }

       NodeIt(const SmartGraph& _G,Node n) : Node(n), G(&_G) { }

       NodeIt(Invalid i) : Node(i) { }

       NodeIt(const SmartGraph& _G) : Node(_G.nodes.size()?0:-1), G(&_G) { }

       NodeIt &operator++() {

 	n=(n+2)%(G->nodes.size()+1)-1; 

 	return *this; 

       }

 //       ///Validity check

 //       operator bool() { return Node::operator bool(); }      

     };

     class Edge {

       friend class SmartGraph;

       template <typename T> friend class EdgeMap;

       //template <typename T> friend class SymSmartGraph::SymEdgeMap;      

       //friend Edge SymSmartGraph::opposite(Edge) const;

       friend class Node;

       friend class NodeIt;

     protected:

       int n;

       friend int SmartGraph::id(Edge e);

     public:

       /// An Edge with id \c n.

       /// \bug It should be

       /// obtained by a member function of the Graph.

       Edge(int nn) {n=nn;}

       Edge() { }

       Edge (Invalid) { n=-1; }

       bool operator==(const Edge i) const {return n==i.n;}

       bool operator!=(const Edge i) const {return n!=i.n;}

       bool operator<(const Edge i) const {return n<i.n;}

       ///\bug This is a workaround until somebody tells me how to

       ///make class \c SymSmartGraph::SymEdgeMap friend of Edge

       int &idref() {return n;}

       const int &idref() const {return n;} 

 //       ///Validity check

 //       operator bool() { return n!=-1; }

    };

     class EdgeIt : public Edge {

       const SmartGraph *G;

       friend class SmartGraph;

     public:

       EdgeIt(const SmartGraph& _G) : Edge(_G.edges.size()-1), G(&_G) { }

       EdgeIt(const SmartGraph& _G, Edge e) : Edge(e), G(&_G) { }

       EdgeIt (Invalid i) : Edge(i) { }

       EdgeIt() : Edge() { }

       ///\bug This is a workaround until somebody tells me how to

       ///make class \c SymSmartGraph::SymEdgeMap friend of Edge

       int &idref() {return n;}

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

 //       ///Validity check

 //       operator bool() { return Edge::operator bool(); }      

     };

     class OutEdgeIt : public Edge {

       const SmartGraph *G;

       friend class SmartGraph;

     public: 

       OutEdgeIt() : Edge() { }

       OutEdgeIt(const SmartGraph& _G, Edge e) : Edge(e), G(&_G) { }

       OutEdgeIt (Invalid i) : Edge(i) { }

       OutEdgeIt(const SmartGraph& _G,const Node v)

 	: Edge(_G.nodes[v.n].first_out), G(&_G) {}

       OutEdgeIt &operator++() { n=G->edges[n].next_out; return *this; }

 //       ///Validity check

 //       operator bool() { return Edge::operator bool(); }      

     };

     class InEdgeIt : public Edge {

       const SmartGraph *G;

       friend class SmartGraph;

     public: 

       InEdgeIt() : Edge() { }

       InEdgeIt(const SmartGraph& _G, Edge e) : Edge(e), G(&_G) { }

       InEdgeIt (Invalid i) : Edge(i) { }

       InEdgeIt(const SmartGraph& _G,Node v)

 	: Edge(_G.nodes[v.n].first_in), G(&_G) { }

       InEdgeIt &operator++() { n=G->edges[n].next_in; return *this; }

 //       ///Validity check

 //       operator bool() { return Edge::operator bool(); }      

     };

     template <typename T> class NodeMap : public DynMapBase<Node>

     {

       std::vector<T> container;

     public:

       typedef T ValueType;

       typedef Node KeyType;

       NodeMap(const SmartGraph &_G) :

 	DynMapBase<Node>(_G), container(_G.maxNodeId())

       {

 	G->dyn_node_maps.push_back(this);

       }

       NodeMap(const SmartGraph &_G,const T &t) :

 	DynMapBase<Node>(_G), container(_G.maxNodeId(),t)

       {

 	G->dyn_node_maps.push_back(this);

       }

       NodeMap(const NodeMap<T> &m) :

  	DynMapBase<Node>(*m.G), container(m.container)

       {

  	G->dyn_node_maps.push_back(this);

       }

       template<typename TT> friend class NodeMap;

       ///\todo It can copy between different types.

       ///\todo We could use 'copy'

       template<typename TT> NodeMap(const NodeMap<TT> &m) :

 	DynMapBase<Node>(*m.G), container(m.container.size())

       {

 	G->dyn_node_maps.push_back(this);

 	typename std::vector<TT>::const_iterator i;

 	for(typename std::vector<TT>::const_iterator i=m.container.begin();

 	    i!=m.container.end();

 	    i++)

 	  container.push_back(*i);

       }

       ~NodeMap()

       {

 	if(G) {

 	  std::vector<DynMapBase<Node>* >::iterator i;

 	  for(i=G->dyn_node_maps.begin();

 	      i!=G->dyn_node_maps.end() && *i!=this; ++i) ;

 	  //if(*i==this) G->dyn_node_maps.erase(i); //FIXME: Way too slow...

 	  //A better way to do that: (Is this really important?)

 	  if(*i==this) {

 	    *i=G->dyn_node_maps.back();

 	    G->dyn_node_maps.pop_back();

 	  }

 	}

       }

       void add(const Node k) 

       {

 	if(k.n>=int(container.size())) container.resize(k.n+1);

       }

       void erase(const Node) { }

       void set(Node n, T a) { container[n.n]=a; }

       //'T& operator[](Node n)' would be wrong here

       typename std::vector<T>::reference

       operator[](Node n) { return container[n.n]; }

       //'const T& operator[](Node n)' would be wrong here

       typename std::vector<T>::const_reference 

       operator[](Node n) const { return container[n.n]; }

       ///\warning There is no safety check at all!

       ///Using operator = between maps attached to different graph may

       ///cause serious problem.

       ///\todo Is this really so?

       ///\todo It can copy between different types.

       const NodeMap<T>& operator=(const NodeMap<T> &m)

       {

 	container = m.container;

 	return *this;

       }

       template<typename TT>

       const NodeMap<T>& operator=(const NodeMap<TT> &m)

       {

 	std::copy(m.container.begin(), m.container.end(), container.begin());

 	return *this;

       }

       void update() {}    //Useless for Dynamic Maps

       void update(T a) {}  //Useless for Dynamic Maps

     };

     template <typename T> class EdgeMap : public DynMapBase<Edge>

     {

       std::vector<T> container;

     public:

       typedef T ValueType;

       typedef Edge KeyType;

       EdgeMap(const SmartGraph &_G) :

 	DynMapBase<Edge>(_G), container(_G.maxEdgeId())

       {

 	//FIXME: What if there are empty Id's?

 	//FIXME: Can I use 'this' in a constructor?

 	G->dyn_edge_maps.push_back(this);

       }

       EdgeMap(const SmartGraph &_G,const T &t) :

 	DynMapBase<Edge>(_G), container(_G.maxEdgeId(),t)

       {

 	G->dyn_edge_maps.push_back(this);

       } 

       EdgeMap(const EdgeMap<T> &m) :

  	DynMapBase<Edge>(*m.G), container(m.container)

       {

  	G->dyn_edge_maps.push_back(this);

       }

       template<typename TT> friend class EdgeMap;

       ///\todo It can copy between different types.

       template<typename TT> EdgeMap(const EdgeMap<TT> &m)

 	: DynMapBase<Edge>(*m.G), container(m.container.size())

       {

 	G->dyn_edge_maps.push_back(this);

 	typename std::vector<TT>::const_iterator i;

 	for(typename std::vector<TT>::const_iterator i=m.container.begin();

 	    i!=m.container.end();

 	    i++)

 	  container.push_back(*i);

       }

       ~EdgeMap()

       {

 	if(G) {

 	  std::vector<DynMapBase<Edge>* >::iterator i;

 	  for(i=G->dyn_edge_maps.begin();

 	      i!=G->dyn_edge_maps.end() && *i!=this; ++i) ;

 	  //if(*i==this) G->dyn_edge_maps.erase(i); //Way too slow...

 	  //A better way to do that: (Is this really important?)

 	  if(*i==this) {

 	    *i=G->dyn_edge_maps.back();

 	    G->dyn_edge_maps.pop_back();

 	  }

 	}

       }

       void add(const Edge k) 

       {

 	if(k.n>=int(container.size())) container.resize(k.n+1);

       }

       void erase(const Edge) { }

       void set(Edge n, T a) { container[n.n]=a; }

       //T get(Edge n) const { return container[n.n]; }

       typename std::vector<T>::reference

       operator[](Edge n) { return container[n.n]; }

       typename std::vector<T>::const_reference

       operator[](Edge n) const { return container[n.n]; }

       ///\warning There is no safety check at all!

       ///Using operator = between maps attached to different graph may

       ///cause serious problem.

       ///\todo Is this really so?

       ///\todo It can copy between different types.

       const EdgeMap<T>& operator=(const EdgeMap<T> &m)

       {

 	container = m.container;

 	return *this;

       }

       template<typename TT>

       const EdgeMap<T>& operator=(const EdgeMap<TT> &m)

       {

 	std::copy(m.container.begin(), m.container.end(), container.begin());

 	return *this;

       }

       void update() {}    //Useless for DynMaps

       void update(T a) {}  //Useless for DynMaps

     };

   };

   ///Graph for bidirectional edges.

   ///The purpose of this graph structure is to handle graphs

   ///having bidirectional edges. Here the function \c addEdge(u,v) adds a pair

   ///of oppositely directed edges.

   ///There is a new edge map type called

   ///\ref SymSmartGraph::SymEdgeMap "SymEdgeMap"

   ///that complements this

   ///feature by

   ///storing shared values for the edge pairs. The usual

   ///\ref GraphSkeleton::EdgeMap "EdgeMap"

   ///can be used

   ///as well.

   ///

   ///The oppositely directed edge can also be obtained easily

   ///using \ref opposite.

   ///\warning It shares the similarity with \ref SmartGraph that

   ///it is not possible to delete edges or nodes from the graph.

   //\sa \ref SmartGraph.

   class SymSmartGraph : public SmartGraph

   {

   public:

     template<typename T> class SymEdgeMap;

     template<typename T> friend class SymEdgeMap;

     SymSmartGraph() : SmartGraph() { }

     SymSmartGraph(const SmartGraph &_g) : SmartGraph(_g) { }

     ///Adds a pair of oppositely directed edges to the graph.

     Edge addEdge(Node u, Node v)

     {

       Edge e = SmartGraph::addEdge(u,v);

       SmartGraph::addEdge(v,u);

       return e;

     }

     ///The oppositely directed edge.

     ///Returns the oppositely directed

     ///pair of the edge \c e.

     static Edge opposite(Edge e)

     {

       Edge f;

       f.idref() = e.idref() - 2*(e.idref()%2) + 1;

       return f;

     }

     ///Common data storage for the edge pairs.

     ///This map makes it possible to store data shared by the oppositely

     ///directed pairs of edges.

     template <typename T> class SymEdgeMap : public DynMapBase<Edge>

     {

       std::vector<T> container;

     public:

       typedef T ValueType;

       typedef Edge KeyType;

       SymEdgeMap(const SymSmartGraph &_G) :

 	DynMapBase<Edge>(_G), container(_G.maxEdgeId()/2)

       {

 	static_cast<const SymSmartGraph*>(G)->dyn_edge_maps.push_back(this);

       }

       SymEdgeMap(const SymSmartGraph &_G,const T &t) :

 	DynMapBase<Edge>(_G), container(_G.maxEdgeId()/2,t)

       {

 	G->dyn_edge_maps.push_back(this);

       }

       SymEdgeMap(const SymEdgeMap<T> &m) :

  	DynMapBase<SymEdge>(*m.G), container(m.container)

       {

  	G->dyn_node_maps.push_back(this);

       }

       //      template<typename TT> friend class SymEdgeMap;

       ///\todo It can copy between different types.

       ///

       template<typename TT> SymEdgeMap(const SymEdgeMap<TT> &m)

 	: DynMapBase<SymEdge>(*m.G), container(m.container.size())

       {

 	G->dyn_node_maps.push_back(this);

 	typename std::vector<TT>::const_iterator i;

 	for(typename std::vector<TT>::const_iterator i=m.container.begin();

 	    i!=m.container.end();

 	    i++)

 	  container.push_back(*i);

       }

       ~SymEdgeMap()

       {

 	if(G) {

 	  std::vector<DynMapBase<Edge>* >::iterator i;

 	  for(i=static_cast<const SymSmartGraph*>(G)->dyn_edge_maps.begin();

 	      i!=static_cast<const SymSmartGraph*>(G)->dyn_edge_maps.end()

 		&& *i!=this; ++i) ;

 	  //if(*i==this) G->dyn_edge_maps.erase(i); //Way too slow...

 	  //A better way to do that: (Is this really important?)

 	  if(*i==this) {

 	    *i=static_cast<const SymSmartGraph*>(G)->dyn_edge_maps.back();

 	    static_cast<const SymSmartGraph*>(G)->dyn_edge_maps.pop_back();

 	  }

 	}

       }

       void add(const Edge k) 

       {

 	if(!k.idref()%2&&k.idref()/2>=int(container.size()))

 	  container.resize(k.idref()/2+1);

       }

       void erase(const Edge k) { }

       void set(Edge n, T a) { container[n.idref()/2]=a; }

       //T get(Edge n) const { return container[n.idref()/2]; }

       typename std::vector<T>::reference

       operator[](Edge n) { return container[n.idref()/2]; }

       typename std::vector<T>::const_reference

       operator[](Edge n) const { return container[n.idref()/2]; }

       ///\warning There is no safety check at all!

       ///Using operator = between maps attached to different graph may

       ///cause serious problem.

       ///\todo Is this really so?

       ///\todo It can copy between different types.

       const SymEdgeMap<T>& operator=(const SymEdgeMap<T> &m)

       {

 	container = m.container;

 	return *this;

       }

       template<typename TT>

       const SymEdgeMap<T>& operator=(const SymEdgeMap<TT> &m)

       {

 	std::copy(m.container.begin(), m.container.end(), container.begin());

 	return *this;

       }

       void update() {}    //Useless for DynMaps

       void update(T a) {}  //Useless for DynMaps

     };

   };

   /// @}  

 } //namespace hugo

 #endif //HUGO_SMART_GRAPH_H