/* -*- 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

#include <lemon/bits/graph_extender.h>

#include <lemon/graph_utils.h>

namespace lemon {

  class StaticGraphBase {

  public:

    StaticGraphBase() 

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

        node_first_out(0), node_first_in(0),

        edge_source(0), edge_target(0), 

        edge_next_in(0), edge_next_out(0) {}

    ~StaticGraphBase() {

      if (node_num != -1) {

        delete[] node_first_out;

        delete[] node_first_in;

        delete[] edge_source;

        delete[] edge_target;

        delete[] edge_next_out;

        delete[] edge_next_in;

      }

    }

    class Node {

      friend class StaticGraphBase;

    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 Edge {

      friend class StaticGraphBase;      

    protected:

      int id;

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

    public:

      Edge() { }

      Edge (Invalid) { id = -1; }

      bool operator==(const Edge& edge) const {return id == edge.id;}

      bool operator!=(const Edge& edge) const {return id != edge.id;}

      bool operator<(const Edge& edge) const {return id < edge.id;}

    };

    Node source(const Edge& e) const { return Node(edge_source[e.id]); }

    Node target(const Edge& e) const { return Node(edge_target[e.id]); }

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

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

    void first(Edge& n) const { n.id = edge_num - 1; }

    void next(Edge& n) const { --n.id; }

    void firstOut(Edge& 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(Edge& e) const { e.id = edge_next_out[e.id]; }

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

    void nextIn(Edge& e) const { e.id = edge_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 Edge& e) const { return e.id; }

    Edge edgeFromId(int id) const { return Edge(id); }

    int maxEdgeId() const { return edge_num - 1; }

    typedef True NodeNumTag;

    int nodeNum() const { return node_num; }

    typedef True EdgeNumTag;

    int edgeNum() const { return edge_num; }

  private:

    template <typename Graph, typename NodeRefMap>

    class EdgeLess {

    public:

      typedef typename Graph::Edge Edge;

      EdgeLess(const Graph &_graph, const NodeRefMap& _nodeRef) 

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

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

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

      }

    private:

      const Graph& graph;

      const NodeRefMap& nodeRef;

    };

  public:

    typedef True BuildTag;

    template <typename Graph, typename NodeRefMap, typename EdgeRefMap>

    void build(const Graph& graph, NodeRefMap& nodeRef, EdgeRefMap& edgeRef) {

      if (node_num != -1) {

        delete[] node_first_out;

        delete[] node_first_in;

        delete[] edge_source;

        delete[] edge_target;

        delete[] edge_next_out;

        delete[] edge_next_in;

      }

      typedef typename Graph::Node GNode;

      typedef typename Graph::Edge GEdge;

      node_num = countNodes(graph);

      edge_num = countEdges(graph);

      node_first_out = new int[node_num + 1];

      node_first_in = new int[node_num];

      edge_source = new int[edge_num];

      edge_target = new int[edge_num];

      edge_next_out = new int[edge_num];

      edge_next_in = new int[edge_num];

      int node_index = 0;

      for (typename Graph::NodeIt n(graph); n != INVALID; ++n) {

        nodeRef[n] = Node(node_index);

        node_first_in[node_index] = -1;

        ++node_index;

      }

      EdgeLess<Graph, NodeRefMap> edgeLess(graph, nodeRef);

      int edge_index = 0;

      for (typename Graph::NodeIt n(graph); n != INVALID; ++n) {

        int source = nodeRef[n].id;

        std::vector<GEdge> edges;

        for (typename Graph::OutEdgeIt e(graph, n); e != INVALID; ++e) {

          edges.push_back(e);

        }

        if (!edges.empty()) {

          node_first_out[source] = edge_index;

          std::sort(edges.begin(), edges.end(), edgeLess);

          for (typename std::vector<GEdge>::iterator it = edges.begin();

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

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

            edgeRef[*it] = Edge(edge_index);

            edge_source[edge_index] = source; 

            edge_target[edge_index] = target;

            edge_next_in[edge_index] = node_first_in[target];

            node_first_in[target] = edge_index;

            edge_next_out[edge_index] = edge_index + 1;

            ++edge_index;

          }

          edge_next_out[edge_index - 1] = -1;

        } else {

          node_first_out[source] = edge_index;

        }

      }

      node_first_out[node_num] = edge_num;

    }

  protected:

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

      e.id = node_first_out[n.id];

    }

    static void fastNextOut(Edge& e) {

      ++e.id;

    }

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

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

    }

  private:

    int node_num;

    int edge_num;

    int *node_first_out;

    int *node_first_in;

    int *edge_source;

    int *edge_target;

    int *edge_next_in;

    int *edge_next_out;

  };

  typedef GraphExtender<StaticGraphBase> ExtendedStaticGraphBase;

  class StaticGraph : public ExtendedStaticGraphBase {

  public:

    typedef ExtendedStaticGraphBase Parent;

  protected:

    using Parent::fastFirstOut;

    using Parent::fastNextOut;

    using Parent::fastLastOut;

  public:

    class OutEdgeIt : public Edge {

    public:

      OutEdgeIt() { }

      OutEdgeIt(Invalid i) : Edge(i) { }

      OutEdgeIt(const StaticGraph& graph, const Node& node) {

	graph.fastFirstOut(*this, node);

	graph.fastLastOut(last, node);

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

      }

      OutEdgeIt(const StaticGraph& graph, const Edge& edge) : Edge(edge) {

        graph.fastLastOut(last, graph.source(edge));

      }

      OutEdgeIt& operator++() { 

        StaticGraph::fastNextOut(*this);

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

        return *this; 

      }

    private:

      Edge last;

    };

  };

}

#endif