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

#ifndef HUGO_SMART_GRAPH_H
#define HUGO_SMART_GRAPH_H

///\file
///\brief SmartGraph and SymSmartGraph classes.

#include <vector>
#include <limits.h>

#include "invalid.h"

namespace hugo {

  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.
  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) = NULL;
      virtual void erase(const Key k) = NULL;
      DynMapBase(const SmartGraph &_G) : G(&_G) {}
      virtual ~DynMapBase() {}
      friend class SmartGraph;
    };
    
  public:
    template <typename T> class EdgeMap;
    template <typename T> class EdgeMap;

    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; }

    Node aNode(OutEdgeIt e) const { return edges[e.n].tail; }
    Node aNode(InEdgeIt e) const { return edges[e.n].head; }

    Node bNode(OutEdgeIt e) const { return edges[e.n].head; }
    Node bNode(InEdgeIt e) const { return edges[e.n].tail; }

    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; }

//     template< typename It >
//     It first() const { It e; first(e); return e; }

//     template< typename It >
//     It first(Node v) const { It e; first(e,v); return e; }

    bool valid(Edge e) const { return e.n!=-1; }
    bool valid(Node n) const { return n.n!=-1; }
    
    void setInvalid(Edge &e) { e.n=-1; }
    void setInvalid(Node &n) { n.n=-1; }
    
    template <typename It> It getNext(It it) const
    { It tmp(it); return next(tmp); }

    NodeIt& next(NodeIt& it) const { 
      it.n=(it.n+2)%(nodes.size()+1)-1; 
      return it; 
    }
    OutEdgeIt& next(OutEdgeIt& it) const
    { it.n=edges[it.n].next_out; return it; }
    InEdgeIt& next(InEdgeIt& it) const
    { it.n=edges[it.n].next_in; return it; }
    EdgeIt& next(EdgeIt& it) const { --it.n; return it; }

    int id(Node v) const { return v.n; }
    int id(Edge e) const { 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;
    }

    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) const; 
      Node(int nn) {n=nn;}
    public:
      Node() {}
      Node (Invalid i) { 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;}
    };
    
    class NodeIt : public Node {
      friend class SmartGraph;
    public:
      NodeIt(const SmartGraph& G) : Node(G.nodes.size()?0:-1) { }
      NodeIt() : Node() { }
    };

    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) const;

      Edge(int nn) {n=nn;}
    public:
      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;}
    };
    
    class EdgeIt : public Edge {
      friend class SmartGraph;
    public:
      EdgeIt(const SmartGraph& G) : Edge(G.edges.size()-1) { }
      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;}
    };
    
    class OutEdgeIt : public Edge {
      friend class SmartGraph;
    public: 
      OutEdgeIt() : Edge() { }
      OutEdgeIt (Invalid i) : Edge(i) { }

      OutEdgeIt(const SmartGraph& G,const Node v)
	: Edge(G.nodes[v.n].first_out) {}
    };
    
    class InEdgeIt : public Edge {
      friend class SmartGraph;
    public: 
      InEdgeIt() : Edge() { }
      InEdgeIt (Invalid i) : Edge(i) { }
      InEdgeIt(const SmartGraph& G,Node v) :Edge(G.nodes[v.n].first_in){}
    };

    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.
      ///
      template<typename TT> NodeMap(const NodeMap<TT> &m) :
	DynMapBase<Node>(*m.G)
      {
	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)
      {
	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_node_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)
      {
	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);
      }
      ~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)
      {
	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.
    Edge opposite(Edge e) const
    {
      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)
      {
	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)
      {
	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 //SMART_GRAPH_H