// -*- 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