#ifndef LIST_GRAPH_HH

#define LIST_GRAPH_HH

#include <iostream>

namespace marci {

  template <typename It>

  int count(It it) { 

    int i=0;

    for( ; it.valid(); ++it) { ++i; } 

    return i;

  }

  class ListGraph {

    class node_item;

    class edge_item;

  public:

    class NodeIt;

    class EachNodeIt;

    class EdgeIt;

    class EachEdgeIt;

    class OutEdgeIt;

    class InEdgeIt;

    class SymEdgeIt;

    template <typename T> class NodeMap;

    template <typename T> class EdgeMap;

  private:

    template <typename T> friend class NodeMap;

    template <typename T> friend class EdgeMap;

    template <typename T>

    class NodeMap {

      const ListGraph& G; 

      std::vector<T> container;

    public:

      typedef T ValueType;

      typedef NodeIt KeyType;

      NodeMap(const ListGraph& _G) : G(_G), container(G.node_id) { }

      NodeMap(const ListGraph& _G, T a) : 

	G(_G), container(G.node_id, a) { }

      void set(NodeIt nit, T a) { container[G.id(nit)]=a; }

      T get(NodeIt nit) const { return container[G.id(nit)]; }

      void resize() { container.resize(G.node_id); }

      void resize(T a) { container.resize(G.node_id, a); }

    };

    template <typename T>

    class EdgeMap {

      const ListGraph& G; 

      std::vector<T> container;

    public:

      typedef T ValueType;

      typedef EdgeIt KeyType;

      EdgeMap(const ListGraph& _G) : G(_G), container(G.edge_id) { }

      EdgeMap(const ListGraph& _G, T a) : 

	G(_G), container(G.edge_id, a) { }

      void set(EdgeIt eit, T a) { container[G.id(eit)]=a; }

      T get(EdgeIt eit) const { return container[G.id(eit)]; }

      void resize() { container.resize(G.edge_id); }

      void resize(T a) { container.resize(G.edge_id, a); }

    };

    int node_id;

    int edge_id;

    int _node_num;

    int _edge_num;

    node_item* _first_node;

    node_item* _last_node;

    class node_item {

      friend class ListGraph;

      friend class NodeIt;

      friend class EachNodeIt;

      friend class EdgeIt;

      friend class EachEdgeIt;

      friend class OutEdgeIt;

      friend class InEdgeIt;

      friend class SymEdgeIt;

      friend std::ostream& operator<<(std::ostream& os, const NodeIt& i);

      friend std::ostream& operator<<(std::ostream& os, const EdgeIt& i);

      //ListGraph* G;

      int id;

      edge_item* _first_out_edge;

      edge_item* _last_out_edge;

      edge_item* _first_in_edge;

      edge_item* _last_in_edge;

      node_item* _next_node;

      node_item* _prev_node;

    public:

      node_item() { }

    };

    class edge_item {

      friend class ListGraph;

      friend class NodeIt;

      friend class EachNodeIt;

      friend class EdgeIt;

      friend class EachEdgeIt;

      friend class OutEdgeIt;

      friend class InEdgeIt;

      friend class SymEdgeIt;

      friend std::ostream& operator<<(std::ostream& os, const EdgeIt& i);

      //ListGraph* G;

      int id;

      node_item* _tail;

      node_item* _head;

      edge_item* _next_out;

      edge_item* _prev_out;

      edge_item* _next_in;

      edge_item* _prev_in;

    public:

      edge_item() { }

    };

    node_item* _add_node() { 

      node_item* p=new node_item;

      p->id=node_id++;

      p->_first_out_edge=0;

      p->_last_out_edge=0;

      p->_first_in_edge=0;

      p->_last_in_edge=0;

      p->_prev_node=_last_node;

      p->_next_node=0;

      if (_last_node) _last_node->_next_node=p;

      _last_node=p;

      if (!_first_node) _first_node=p;

      ++_node_num;

      return p;

    }

    edge_item* _add_edge(node_item* _tail, node_item* _head) {

      edge_item* e=new edge_item;

      e->id=edge_id++;

      e->_tail=_tail;

      e->_head=_head;

      e->_prev_out=_tail->_last_out_edge;

      if (_tail->_last_out_edge) (_tail->_last_out_edge)->_next_out=e;

      _tail->_last_out_edge=e;

      if (!_tail->_first_out_edge) _tail->_first_out_edge=e; 

      e->_next_out=0;

      e->_prev_in=_head->_last_in_edge;

      if (_head->_last_in_edge) (_head->_last_in_edge)->_next_in=e;

      _head->_last_in_edge=e;

      if (!_head->_first_in_edge) { _head->_first_in_edge=e; } 

      e->_next_in=0;

      ++_edge_num;

      return e;

    }

    //deletes a node which has no out edge and no in edge

    void _delete_node(node_item* v) {

      if (v->_next_node) (v->_next_node)->_prev_node=v->_prev_node; else 

	_last_node=v->_prev_node;

      if (v->_prev_node) (v->_prev_node)->_next_node=v->_next_node; else 

	_first_node=v->_next_node;

      delete v;

      --_node_num;

    }

    void _delete_edge(edge_item* e) {

      if (e->_next_out) (e->_next_out)->_prev_out=e->_prev_out; else 

	(e->_tail)->_last_out_edge=e->_prev_out;

      if (e->_prev_out) (e->_prev_out)->_next_out=e->_next_out; else 

	(e->_tail)->_first_out_edge=e->_next_out;

      if (e->_next_in) (e->_next_in)->_prev_in=e->_prev_in; else 

	(e->_head)->_last_in_edge=e->_prev_in;

      if (e->_prev_in) (e->_prev_in)->_next_in=e->_next_in; else 

	(e->_head)->_first_in_edge=e->_next_in;

      delete e;

      --_edge_num;

    }

    void _set_tail(edge_item* e, node_item* _tail) {

      if (e->_next_out) (e->_next_out)->_prev_out=e->_prev_out; else 

	(e->_tail)->_last_out_edge=e->_prev_out;

      if (e->_prev_out) (e->_prev_out)->_next_out=e->_next_out; else 

	(e->_tail)->_first_out_edge=e->_next_out;

      e->_tail=_tail;

      e->_prev_out=_tail->_last_out_edge;

      if (_tail->_last_out_edge) (_tail->_last_out_edge)->_next_out=e;

      _tail->_last_out_edge=e;

      if (!_tail->_first_out_edge) _tail->_first_out_edge=e; 

      e->_next_out=0;

    }

    void _set_head(edge_item* e, node_item* _head) {

      if (e->_next_in) (e->_next_in)->_prev_in=e->_prev_in; else 

	(e->_head)->_last_in_edge=e->_prev_in;

      if (e->_prev_in) (e->_prev_in)->_next_in=e->_next_in; else 

	(e->_head)->_first_in_edge=e->_next_in;

      e->_head=_head;

      e->_prev_in=_head->_last_in_edge;

      if (_head->_last_in_edge) (_head->_last_in_edge)->_next_in=e;

      _head->_last_in_edge=e;

      if (!_head->_first_in_edge) { _head->_first_in_edge=e; } 

      e->_next_in=0;

    }

  public:

    /* default constructor */

    ListGraph() : node_id(0), edge_id(0), _node_num(0), _edge_num(0), _first_node(0), _last_node(0) { }

    ~ListGraph() { 

      while (first<EachNodeIt>().valid()) erase(first<EachNodeIt>());

    }

    int nodeNum() const { return _node_num; }

    int edgeNum() const { return _edge_num; }

    /* functions to construct iterators from the graph, or from each other */

    //EachNodeIt firstNode() const { return EachNodeIt(*this); }

    //EachEdgeIt firstEdge() const { return EachEdgeIt(*this); }

    //OutEdgeIt firstOutEdge(const NodeIt v) const { return OutEdgeIt(v); }

    //InEdgeIt firstInEdge(const NodeIt v) const { return InEdgeIt(v); }

    //SymEdgeIt firstSymEdge(const NodeIt v) const { return SymEdgeIt(v); }

    NodeIt tail(EdgeIt e) const { return e.tailNode(); }

    NodeIt head(EdgeIt e) const { return e.headNode(); }

    NodeIt aNode(const OutEdgeIt& e) const { return e.aNode(); }

    NodeIt aNode(const InEdgeIt& e) const { return e.aNode(); }

    NodeIt aNode(const SymEdgeIt& e) const { return e.aNode(); }

    NodeIt bNode(const OutEdgeIt& e) const { return e.bNode(); }

    NodeIt bNode(const InEdgeIt& e) const { return e.bNode(); }

    NodeIt bNode(const SymEdgeIt& e) const { return e.bNode(); }

    //NodeIt invalid_node() { return NodeIt(); }

    //EdgeIt invalid_edge() { return EdgeIt(); }

    //OutEdgeIt invalid_out_edge() { return OutEdgeIt(); }

    //InEdgeIt invalid_in_edge() { return InEdgeIt(); }

    //SymEdgeIt invalid_sym_edge() { return SymEdgeIt(); }

    /* same methods in other style */

    /* for experimental purpose */

    void getFirst(EachNodeIt& v) const { v=EachNodeIt(*this); }

    void getFirst(EachEdgeIt& e) const { e=EachEdgeIt(*this); }

    void getFirst(OutEdgeIt& e, NodeIt v) const { e=OutEdgeIt(v); }

    void getFirst(InEdgeIt& e, NodeIt v) const { e=InEdgeIt(v); }

    void getFirst(SymEdgeIt& e, NodeIt v) const { e=SymEdgeIt(v); }

    //void getTail(NodeIt& n, const EdgeIt& e) const { n=tail(e); }

    //void getHead(NodeIt& n, const EdgeIt& e) const { n=head(e); }

    //void getANode(NodeIt& n, const OutEdgeIt& e) const { n=e.aNode(); }

    //void getANode(NodeIt& n, const InEdgeIt& e) const { n=e.aNode(); }

    //void getANode(NodeIt& n, const SymEdgeIt& e) const { n=e.aNode(); }

    //void getBNode(NodeIt& n, const OutEdgeIt& e) const { n=e.bNode(); }

    //void getBNode(NodeIt& n, const InEdgeIt& e) const { n=e.bNode(); }

    //void getBNode(NodeIt& n, const SymEdgeIt& e) const { n=e.bNode(); }

    //void get_invalid(NodeIt& n) { n=NodeIt(); }

    //void get_invalid(EdgeIt& e) { e=EdgeIt(); }

    //void get_invalid(OutEdgeIt& e) { e=OutEdgeIt(); }

    //void get_invalid(InEdgeIt& e) { e=InEdgeIt(); }

    //void get_invalid(SymEdgeIt& e) { e=SymEdgeIt(); }

    template< typename It >

    It first() const { 

      It e;

      getFirst(e);

      return e; 

    }

    template< typename It >

    It first(NodeIt v) const { 

      It e;

      getFirst(e, v);

      return e; 

    }

    /* for getting id's of graph objects */

    /* these are important for the implementation of property vectors */

    int id(NodeIt v) const { return v.node->id; }

    int id(EdgeIt e) const { return e.edge->id; }

    /* adding nodes and edges */

    NodeIt addNode() { return NodeIt(_add_node()); }

    EdgeIt addEdge(NodeIt u, NodeIt v) {

      return EdgeIt(_add_edge(u.node, v.node)); 

    }

    void erase(NodeIt i) { 

      while (first<OutEdgeIt>(i).valid()) erase(first<OutEdgeIt>(i));

      while (first<InEdgeIt>(i).valid()) erase(first<InEdgeIt>(i));

      _delete_node(i.node); 

    }

    void erase(EdgeIt e) { _delete_edge(e.edge); }

    void clear() { 

      while (first<EachNodeIt>().valid()) erase(first<EachNodeIt>());

    }

    void setTail(EdgeIt e, NodeIt tail) {

      _set_tail(e.edge, tail.node); 

    }

    void setHead(EdgeIt e, NodeIt head) {

      _set_head(e.edge, head.node); 

    }

    /* stream operations, for testing purpose */

    friend std::ostream& operator<<(std::ostream& os, const NodeIt& i) { 

      os << i.node->id; return os; 

    }

    friend std::ostream& operator<<(std::ostream& os, const EdgeIt& i) { 

      os << "(" << i.edge->_tail->id << "--" << i.edge->id << "->" << i.edge->_head->id << ")"; 

      return os; 

    }

    class NodeIt {

      friend class ListGraph;

      friend class EdgeIt;

      friend class OutEdgeIt;

      friend class InEdgeIt;

      friend class SymEdgeIt;

    protected:

      node_item* node;

      friend int ListGraph::id(NodeIt v) const; 

    public:

      NodeIt() : node(0) { }

      NodeIt(node_item* _node) : node(_node) { }

      bool valid() const { return (node!=0); }

      //void makeInvalid() { node=0; }

      friend bool operator==(const NodeIt& u, const NodeIt& v) { 

	return v.node==u.node; 

      } 

      friend bool operator!=(const NodeIt& u, const NodeIt& v) { 

	return v.node!=u.node; 

      } 

      friend std::ostream& operator<<(std::ostream& os, const NodeIt& i);

    };

    class EachNodeIt : public NodeIt {

      friend class ListGraph;

    protected:

      EachNodeIt(const ListGraph& G) : NodeIt(G._first_node) { }

    public:

      EachNodeIt() : NodeIt() { }

      EachNodeIt(node_item* v) : NodeIt(v) { }

      EachNodeIt& operator++() { node=node->_next_node; return *this; }

    };

    class EdgeIt {

      friend class ListGraph;

      friend class NodeIt;

      friend class EachNodeIt;

    protected:

      edge_item* edge;

      friend int ListGraph::id(EdgeIt e) const;

    public:

      EdgeIt() : edge(0) { }

      //EdgeIt() { }

      EdgeIt(edge_item* _edge) : edge(_edge) { }

      bool valid() const { return (edge!=0); }

      //void makeInvalid() { edge=0; }

      friend bool operator==(const EdgeIt& u, const EdgeIt& v) { 

	return v.edge==u.edge; 

      } 

      friend bool operator!=(const EdgeIt& u, const EdgeIt& v) { 

	return v.edge!=u.edge; 

      } 

    protected:

      NodeIt tailNode() const { return NodeIt(edge->_tail); }

      NodeIt headNode() const { return NodeIt(edge->_head); }

    public:

      friend std::ostream& operator<<(std::ostream& os, const EdgeIt& i);

    };

    class EachEdgeIt : public EdgeIt {

      friend class ListGraph;

    protected:

      EachEdgeIt(const ListGraph& G) {

	node_item* v=G._first_node;

	if (v) edge=v->_first_out_edge; else edge=0;

	while (v && !edge) { v=v->_next_node; if (v) edge=v->_first_out_edge; }

      }

    public:

      EachEdgeIt() : EdgeIt() { }

      EachEdgeIt(edge_item* _e) : EdgeIt(_e) { }

      EachEdgeIt& operator++() { 

	node_item* v=edge->_tail;

	edge=edge->_next_out; 

	while (v && !edge) { v=v->_next_node; if (v) edge=v->_first_out_edge; }

	return *this;

      }

    };

    class OutEdgeIt : public EdgeIt {

      friend class ListGraph;

      node_item* v;

    protected:

      OutEdgeIt(const NodeIt& _v) : v(_v.node) { edge=v->_first_out_edge; }

    public:

      OutEdgeIt() : EdgeIt(), v(0) { }

      OutEdgeIt(const ListGraph& G, NodeIt _v) : v(_v.node) { edge=v->_first_out_edge; }

      OutEdgeIt& operator++() { edge=edge->_next_out; return *this; }

    protected:

      NodeIt aNode() const { return NodeIt(v); }

      NodeIt bNode() const { 

	return (edge->_tail==v) ? NodeIt(edge->_head) : NodeIt(edge->_tail); }

    };

    class InEdgeIt : public EdgeIt {

      friend class ListGraph;

      node_item* v;

    protected:

      InEdgeIt(const NodeIt& _v) : v(_v.node) { edge=v->_first_in_edge; }

    public:

      InEdgeIt() : EdgeIt(), v(0) { }

      InEdgeIt(const ListGraph& G, NodeIt _v) : v(_v.node) { edge=v->_first_in_edge; }

      InEdgeIt& operator++() { edge=edge->_next_in; return *this; }

    protected:

      NodeIt aNode() const { return NodeIt(v); }

      NodeIt bNode() const { 

	return (edge->_tail==v) ? NodeIt(edge->_head) : NodeIt(edge->_tail); }

    };

    class SymEdgeIt : public EdgeIt {

      friend class ListGraph;

      bool out_or_in; //1 iff out, 0 iff in

      node_item* v;

    protected:

      SymEdgeIt(const NodeIt& _v) : v(_v.node) { 

	out_or_in=1;

	edge=v->_first_out_edge; 

	if (!edge) { edge=v->_first_in_edge; out_or_in=0; }

      }

    public:

      SymEdgeIt() : EdgeIt(), v(0) { }

      SymEdgeIt(const ListGraph& G, NodeIt _v) : v(_v.node) { 

	out_or_in=1;

	edge=v->_first_out_edge; 

	if (!edge) { edge=v->_first_in_edge; out_or_in=0; }

      }

      SymEdgeIt& operator++() { 

	if (out_or_in) { 

	  edge=edge->_next_out; 

	  if (!edge) { out_or_in=0; edge=v->_first_in_edge; }

	} else {

	  edge=edge->_next_in; 

	}

	return *this;

      }

    protected:

      NodeIt aNode() const { return NodeIt(v); }

      NodeIt bNode() const { 

	return (edge->_tail==v) ? NodeIt(edge->_head) : NodeIt(edge->_tail); }

    };

  };

  /*

  template< typename T >

  T ListGraph::first() const { 

    std::cerr << "Invalid use of template<typemane T> T ListGraph::first<T>();" << std::endl; 

    return T(); 

  }

  template<>

  ListGraph::EachNodeIt ListGraph::first<ListGraph::EachNodeIt>() const { 

    return firstNode(); 

  }

  template<>

  ListGraph::EachEdgeIt ListGraph::first<ListGraph::EachEdgeIt>() const { 

    return firstEdge(); 

  }

  template< typename T >

  T ListGraph::first(ListGraph::NodeIt v) const {

    std::cerr << "Invalid use of template<typemane T> T ListGraph::first<T>(ListGRaph::NodeIt);" << std::endl; 

    return T(); 

  } 

  template<>

  ListGraph::OutEdgeIt ListGraph::first<ListGraph::OutEdgeIt>(const ListGraph::NodeIt v) const { 

    return firstOutEdge(v); 

  }

  template<>

  ListGraph::InEdgeIt ListGraph::first<ListGraph::InEdgeIt>(const ListGraph::NodeIt v) const { 

    return firstInEdge(v); 

  }

  template<>

  ListGraph::SymEdgeIt ListGraph::first<ListGraph::SymEdgeIt>(const ListGraph::NodeIt v) const { 

    return firstSymEdge(v); 

  }

  */

} //namespace marci

#endif //LIST_GRAPH_HH