/* -*- C++ -*-

 *

 * This file is a part of LEMON, a generic C++ optimization library

 *

 * Copyright (C) 2003-2006

 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

 * (Egervary Research Group on Combinatorial Optimization, 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_BITS_BASE_EXTENDER_H

#define LEMON_BITS_BASE_EXTENDER_H

#include <lemon/bits/invalid.h>

#include <lemon/error.h>

#include <lemon/bits/map_extender.h>

#include <lemon/bits/default_map.h>

#include <lemon/concept_check.h>

#include <lemon/concept/maps.h>

///\ingroup graphbits

///\file

///\brief Extenders for the graph types

namespace lemon {

  /// \ingroup graphbits

  ///

  /// \brief BaseExtender for the UGraphs

  template <typename Base>

  class UndirGraphExtender : public Base {

  public:

    typedef Base Parent;

    typedef typename Parent::Edge UEdge;

    typedef typename Parent::Node Node;

    typedef True UndirectedTag;

    class Edge : public UEdge {

      friend class UndirGraphExtender;

    protected:

      bool forward;

      Edge(const UEdge &ue, bool _forward) :

        UEdge(ue), forward(_forward) {}

    public:

      Edge() {}

      /// Invalid edge constructor

      Edge(Invalid i) : UEdge(i), forward(true) {}

      bool operator==(const Edge &that) const {

	return forward==that.forward && UEdge(*this)==UEdge(that);

      }

      bool operator!=(const Edge &that) const {

	return forward!=that.forward || UEdge(*this)!=UEdge(that);

      }

      bool operator<(const Edge &that) const {

	return forward<that.forward ||

	  (!(that.forward<forward) && UEdge(*this)<UEdge(that));

      }

    };

    using Parent::source;

    /// Source of the given Edge.

    Node source(const Edge &e) const {

      return e.forward ? Parent::source(e) : Parent::target(e);

    }

    using Parent::target;

    /// Target of the given Edge.

    Node target(const Edge &e) const {

      return e.forward ? Parent::target(e) : Parent::source(e);

    }

    /// \brief Directed edge from an undirected edge.

    ///

    /// Returns a directed edge corresponding to the specified UEdge.

    /// If the given bool is true the given undirected edge and the

    /// returned edge have the same source node.

    static Edge direct(const UEdge &ue, bool d) {

      return Edge(ue, d);

    }

    /// Returns whether the given directed edge is same orientation as the

    /// corresponding undirected edge.

    ///

    /// \todo reference to the corresponding point of the undirected graph

    /// concept. "What does the direction of an undirected edge mean?"

    static bool direction(const Edge &e) { return e.forward; }

    using Parent::first;

    using Parent::next;

    void first(Edge &e) const {

      Parent::first(e);

      e.forward=true;

    }

    void next(Edge &e) const {

      if( e.forward ) {

	e.forward = false;

      }

      else {

	Parent::next(e);

	e.forward = true;

      }

    }

    void firstOut(Edge &e, const Node &n) const {

      Parent::firstIn(e,n);

      if( UEdge(e) != INVALID ) {

	e.forward = false;

      }

      else {

	Parent::firstOut(e,n);

	e.forward = true;

      }

    }

    void nextOut(Edge &e) const {

      if( ! e.forward ) {

	Node n = Parent::target(e);

	Parent::nextIn(e);

	if( UEdge(e) == INVALID ) {

	  Parent::firstOut(e, n);

	  e.forward = true;

	}

      }

      else {

	Parent::nextOut(e);

      }

    }

    void firstIn(Edge &e, const Node &n) const {

      Parent::firstOut(e,n);

      if( UEdge(e) != INVALID ) {

	e.forward = false;

      }

      else {

	Parent::firstIn(e,n);

	e.forward = true;

      }

    }

    void nextIn(Edge &e) const {

      if( ! e.forward ) {

	Node n = Parent::source(e);

	Parent::nextOut(e);

	if( UEdge(e) == INVALID ) {

	  Parent::firstIn(e, n);

	  e.forward = true;

	}

      }

      else {

	Parent::nextIn(e);

      }

    }

    void firstInc(UEdge &e, bool &d, const Node &n) const {

      d = true;

      Parent::firstOut(e, n);

      if (e != INVALID) return;

      d = false;

      Parent::firstIn(e, n);

    }

    void nextInc(UEdge &e, bool &d) const {

      if (d) {

	Node s = Parent::source(e);

	Parent::nextOut(e);

	if (e != INVALID) return;

	d = false;

	Parent::firstIn(e, s);

      } else {

	Parent::nextIn(e);

      }

    }

    Node nodeFromId(int id) const {

      return Parent::nodeFromId(id);

    }

    Edge edgeFromId(int id) const {

      return direct(Parent::edgeFromId(id >> 1), bool(id & 1));

    }

    UEdge uEdgeFromId(int id) const {

      return Parent::edgeFromId(id);

    }

    int id(const Node &n) const {

      return Parent::id(n);

    }

    int id(const UEdge &e) const {

      return Parent::id(e);

    }

    int id(const Edge &e) const {

      return 2 * Parent::id(e) + int(e.forward);

    }

    int maxNodeId() const {

      return Parent::maxNodeId();

    }

    int maxEdgeId() const {

      return 2 * Parent::maxEdgeId() + 1;

    }

    int maxUEdgeId() const {

      return Parent::maxEdgeId();

    }

    int edgeNum() const {

      return 2 * Parent::edgeNum();

    }

    int uEdgeNum() const {

      return Parent::edgeNum();

    }

    Edge findEdge(Node source, Node target, Edge prev) const {

      if (prev == INVALID) {

	UEdge edge = Parent::findEdge(source, target);

	if (edge != INVALID) return direct(edge, true);

	edge = Parent::findEdge(target, source);

	if (edge != INVALID) return direct(edge, false);

      } else if (direction(prev)) {

	UEdge edge = Parent::findEdge(source, target, prev);

	if (edge != INVALID) return direct(edge, true);

	edge = Parent::findEdge(target, source);

	if (edge != INVALID) return direct(edge, false);	

      } else {

	UEdge edge = Parent::findEdge(target, source, prev);

	if (edge != INVALID) return direct(edge, false);	      

      }

      return INVALID;

    }

    UEdge findUEdge(Node source, Node target, UEdge prev) const {

      if (prev == INVALID) {

	UEdge edge = Parent::findEdge(source, target);

	if (edge != INVALID) return edge;

	edge = Parent::findEdge(target, source);

	if (edge != INVALID) return edge;

      } else if (Parent::source(prev) == source) {

	UEdge edge = Parent::findEdge(source, target, prev);

	if (edge != INVALID) return edge;

	edge = Parent::findEdge(target, source);

	if (edge != INVALID) return edge;	

      } else {

	UEdge edge = Parent::findEdge(target, source, prev);

	if (edge != INVALID) return edge;	      

      }

      return INVALID;

    }

  };

}

#endif