/* -*- C++ -*-

 *

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

 *

 * Copyright (C) 2003-2008

 * 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_STATIC_GRAPH_H

#define LEMON_STATIC_GRAPH_H

///\ingroup graphs

///\file

///\brief StaticDigraph class.

#include <lemon/core.h>

#include <lemon/bits/graph_extender.h>

namespace lemon {

  class StaticDigraphBase {

  public:

    StaticDigraphBase() 

      : node_num(-1), arc_num(0), 

        node_first_out(NULL), node_first_in(NULL),

        arc_source(NULL), arc_target(NULL), 

        arc_next_in(NULL), arc_next_out(NULL) {}

    ~StaticDigraphBase() {

      if (node_num != -1) {

        delete[] node_first_out;

        delete[] node_first_in;

        delete[] arc_source;

        delete[] arc_target;

        delete[] arc_next_out;

        delete[] arc_next_in;

      }

    }

    class Node {

      friend class StaticDigraphBase;

    protected:

      int id;

      Node(int _id) : id(_id) {}

    public:

      Node() {}

      Node (Invalid) : id(-1) {}

      bool operator==(const Node& node) const { return id == node.id; }

      bool operator!=(const Node& node) const { return id != node.id; }

      bool operator<(const Node& node) const { return id < node.id; }

    };

    class Arc {

      friend class StaticDigraphBase;      

    protected:

      int id;

      Arc(int _id) : id(_id) {}

    public:

      Arc() { }

      Arc (Invalid) : id(-1) {}

      bool operator==(const Arc& arc) const { return id == arc.id; }

      bool operator!=(const Arc& arc) const { return id != arc.id; }

      bool operator<(const Arc& arc) const { return id < arc.id; }

    };

    Node source(const Arc& e) const { return Node(arc_source[e.id]); }

    Node target(const Arc& e) const { return Node(arc_target[e.id]); }

    void first(Node& n) const { n.id = node_num - 1; }

    static void next(Node& n) { --n.id; }

    void first(Arc& e) const { e.id = arc_num - 1; }

    static void next(Arc& e) { --e.id; }

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

      e.id = node_first_out[n.id] != node_first_out[n.id + 1] ? 

        node_first_out[n.id] : -1;

    }

    void nextOut(Arc& e) const { e.id = arc_next_out[e.id]; }

    void firstIn(Arc& e, const Node& n) const { e.id = node_first_in[n.id]; }

    void nextIn(Arc& e) const { e.id = arc_next_in[e.id]; }

    int id(const Node& n) const { return n.id; }

    Node nodeFromId(int id) const { return Node(id); }

    int maxNodeId() const { return node_num - 1; }

    int id(const Arc& e) const { return e.id; }

    Arc arcFromId(int id) const { return Arc(id); }

    int maxArcId() const { return arc_num - 1; }

    typedef True NodeNumTag;

    typedef True ArcNumTag;

    int nodeNum() const { return node_num; }

    int arcNum() const { return arc_num; }

  private:

    template <typename Digraph, typename NodeRefMap>

    class ArcLess {

    public:

      typedef typename Digraph::Arc Arc;

      ArcLess(const Digraph &_graph, const NodeRefMap& _nodeRef) 

        : digraph(_graph), nodeRef(_nodeRef) {}

      bool operator()(const Arc& left, const Arc& right) const {

	return nodeRef[digraph.target(left)] < nodeRef[digraph.target(right)];

      }

    private:

      const Digraph& digraph;

      const NodeRefMap& nodeRef;

    };

  public:

    typedef True BuildTag;

    template <typename Digraph, typename NodeRefMap, typename ArcRefMap>

    void build(const Digraph& digraph, NodeRefMap& nodeRef, ArcRefMap& arcRef) {

      if (node_num != -1) {

        delete[] node_first_out;

        delete[] node_first_in;

        delete[] arc_source;

        delete[] arc_target;

        delete[] arc_next_out;

        delete[] arc_next_in;

      }

      typedef typename Digraph::Node GNode;

      typedef typename Digraph::Arc GArc;

      node_num = countNodes(digraph);

      arc_num = countArcs(digraph);

      node_first_out = new int[node_num + 1];

      node_first_in = new int[node_num];

      arc_source = new int[arc_num];

      arc_target = new int[arc_num];

      arc_next_out = new int[arc_num];

      arc_next_in = new int[arc_num];

      int node_index = 0;

      for (typename Digraph::NodeIt n(digraph); n != INVALID; ++n) {

        nodeRef[n] = Node(node_index);

        node_first_in[node_index] = -1;

        ++node_index;

      }

      ArcLess<Digraph, NodeRefMap> arcLess(digraph, nodeRef);

      int arc_index = 0;

      for (typename Digraph::NodeIt n(digraph); n != INVALID; ++n) {

        int source = nodeRef[n].id;

        std::vector<GArc> arcs;

        for (typename Digraph::OutArcIt e(digraph, n); e != INVALID; ++e) {

          arcs.push_back(e);

        }

        if (!arcs.empty()) {

          node_first_out[source] = arc_index;

          std::sort(arcs.begin(), arcs.end(), arcLess);

          for (typename std::vector<GArc>::iterator it = arcs.begin();

               it != arcs.end(); ++it) {

            int target = nodeRef[digraph.target(*it)].id;

            arcRef[*it] = Arc(arc_index);

            arc_source[arc_index] = source; 

            arc_target[arc_index] = target;

            arc_next_in[arc_index] = node_first_in[target];

            node_first_in[target] = arc_index;

            arc_next_out[arc_index] = arc_index + 1;

            ++arc_index;

          }

          arc_next_out[arc_index - 1] = -1;

        } else {

          node_first_out[source] = arc_index;

        }

      }

      node_first_out[node_num] = arc_num;

    }

  protected:

    void fastFirstOut(Arc& e, const Node& n) const {

      e.id = node_first_out[n.id];

    }

    static void fastNextOut(Arc& e) {

      ++e.id;

    }

    void fastLastOut(Arc& e, const Node& n) const {

      e.id = node_first_out[n.id + 1];

    }

  private:

    int node_num;

    int arc_num;

    int *node_first_out;

    int *node_first_in;

    int *arc_source;

    int *arc_target;

    int *arc_next_in;

    int *arc_next_out;

  };

  typedef DigraphExtender<StaticDigraphBase> ExtendedStaticDigraphBase;

  class StaticDigraph : public ExtendedStaticDigraphBase {

  public:

    typedef ExtendedStaticDigraphBase Parent;

  protected:

    using Parent::fastFirstOut;

    using Parent::fastNextOut;

    using Parent::fastLastOut;

  public:

    class OutArcIt : public Arc {

    public:

      OutArcIt() { }

      OutArcIt(Invalid i) : Arc(i) { }

      OutArcIt(const StaticDigraph& digraph, const Node& node) {

	digraph.fastFirstOut(*this, node);

	digraph.fastLastOut(last, node);

        if (last == *this) *this = INVALID;

      }

      OutArcIt(const StaticDigraph& digraph, const Arc& arc) : Arc(arc) {

        if (arc != INVALID) {

          digraph.fastLastOut(last, digraph.source(arc));

        }

      }

      OutArcIt& operator++() { 

        StaticDigraph::fastNextOut(*this);

        if (last == *this) *this = INVALID;

        return *this; 

      }

    private:

      Arc last;

    };

  };

}

#endif