/* -*- C++ -*-
 * lemon/dimacs.h - Part of LEMON, a generic C++ optimization library
 *
 * Copyright (C) 2005 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_DIMACS_H
#define LEMON_DIMACS_H

#include <iostream>
#include <string>
#include <vector>
#include <lemon/maps.h>
#include <lemon/invalid.h>

/// \ingroup dimacs_group
/// \file
/// \brief Dimacs file format reader.

namespace lemon {

  ///
  ///@defgroup dimacs_group DIMACS format
  ///\brief Read and write files in DIMACS format
  ///
  ///Tools to read a graph from or write it to a file in DIMACS format
  ///data
  ///\ingroup io_group

  /// \addtogroup dimacs_group
  /// @{

  /// Dimacs min cost flow reader function.

  /// This function reads a min cost flow instance from dimacs format,
  /// i.e. from dimacs files having a line starting with
  /// \code
  /// p "min"
  /// \endcode
  /// At the beginning \c g is cleared by \c g.clear(). The edge
  /// capacities are written to \c capacity, \c s and \c t are set to
  /// the source and the target nodes resp. and the cost of the edges
  /// are written to \c cost.
  ///
  /// \author Marton Makai
  template<typename Graph, typename CapacityMap, typename CostMap>
  void readDimacs(std::istream& is, Graph &g, CapacityMap& capacity, 
		  typename Graph::Node &s, typename Graph::Node &t, 
		  CostMap& cost) {
    g.clear();
    typename CapacityMap::Value _cap;
    typename CostMap::Value _cost;
    char d;
    std::string problem;
    char c;
    int i, j;
    std::string str;
    int n, m; 
    typename Graph::Edge e;
    std::vector<typename Graph::Node> nodes;
    while (is>>c) {
      switch (c) {
      case 'c': //comment
	getline(is, str);
	break;
      case 'p': //problem definition
	is >> problem >> n >> m;
	getline(is, str);
	nodes.resize(n+1);
	for (int k=1; k<=n; ++k) nodes[k]=g.addNode();
	break;
      case 'n': //node definition
	if (problem=="sp") { //shortest path problem
	  is >> i;
	  getline(is, str);
	  s=nodes[i];
	}
	if (problem=="max" || problem=="min") { //((max) or (min cost)) flow problem
	  is >> i >> d;
	  getline(is, str);
	  if (d=='s') s=nodes[i];
	  if (d=='t') t=nodes[i];
	}
	break;
      case 'a':
	if ( problem == "max" || problem == "sp") {
	  is >> i >> j >> _cap;
	  getline(is, str);
	  e=g.addEdge(nodes[i], nodes[j]);
	  //capacity.update();
	  capacity.set(e, _cap);
	} else {
	  if ( problem == "min" ) {
	    is >> i >> j >> _cap >> _cost;
	    getline(is, str);
	    e=g.addEdge(nodes[i], nodes[j]);
	    //capacity.update();
	    capacity.set(e, _cap);
	    //cost.update();
	    cost.set(e, _cost);
	  } else {
	    is >> i >> j;
	    getline(is, str);
	    g.addEdge(nodes[i], nodes[j]);
	  }
	}
	break;
      }
    }
  }


  /// Dimacs max flow reader function.

  /// This function reads a max flow instance from dimacs format,
  /// i.e. from dimacs files having a line starting with
  /// \code
  /// p "max"
  /// \endcode
  ///At the beginning \c g is cleared by \c g.clear(). The
  /// edge capacities are written to \c capacity and \c s and \c t are
  /// set to the source and the target nodes.
  ///
  /// \author Marton Makai
  template<typename Graph, typename CapacityMap>
  void readDimacs(std::istream& is, Graph &g, CapacityMap& capacity, 
		  typename Graph::Node &s, typename Graph::Node &t) {
    NullMap<typename Graph::Edge, int> n;
    readDimacs(is, g, capacity, s, t, n);
  }


  /// Dimacs shortest path reader function.

  /// This function reads a shortest path instance from dimacs format,
  /// i.e. from dimacs files having a line starting with
  /// \code
  /// p "sp"
  /// \endcode
  /// At the beginning \c g is cleared by \c g.clear(). The edge
  /// capacities are written to \c capacity and \c s is set to the
  /// source node.
  ///
  /// \author Marton Makai
  template<typename Graph, typename CapacityMap>
  void readDimacs(std::istream& is, Graph &g, CapacityMap& capacity, 
		  typename Graph::Node &s) {
    NullMap<typename Graph::Edge, int> n;
    readDimacs(is, g, capacity, s, s, n);
  }


  /// Dimacs capacitated graph reader function.

  /// This function reads an edge capacitated graph instance from
  /// dimacs format.  At the beginning \c g is cleared by \c g.clear()
  /// and the edge capacities are written to \c capacity.
  ///
  /// \author Marton Makai
  template<typename Graph, typename CapacityMap>
  void readDimacs(std::istream& is, Graph &g, CapacityMap& capacity) {
    typename Graph::Node u;
    NullMap<typename Graph::Edge, int> n;
    readDimacs(is, g, capacity, u, u, n);
  }


  /// Dimacs plain graph reader function.

  /// This function reads a graph without any designated nodes and
  /// maps from dimacs format, i.e. from dimacs files having a line
  /// starting with
  /// \code
  /// p "mat"
  /// \endcode
  /// At the beginning \c g is cleared
  /// by \c g.clear().
  ///
  /// \author Marton Makai
  template<typename Graph>
  void readDimacs(std::istream& is, Graph &g) {
    typename Graph::Node u;
    NullMap<typename Graph::Edge, int> n;
    readDimacs(is, g, n, u, u, n);
  }
  


  
  /// write matching problem
  template<typename Graph>
  void writeDimacs(std::ostream& os, const Graph &g) {
    typedef typename Graph::NodeIt NodeIt;
    typedef typename Graph::EdgeIt EdgeIt;  
    
    typename Graph::template NodeMap<int> nodes(g);

    os << "c matching problem" << std::endl;

    int i=1;
    for(NodeIt v(g); v!=INVALID; ++v) {
      nodes.set(v, i);
      ++i;
    }    
    
    os << "p mat " << g.nodeNum() << " " << g.edgeNum() << std::endl;

    for(EdgeIt e(g); e!=INVALID; ++e) {
      os << "a " << nodes[g.source(e)] << " " << nodes[g.target(e)] << std::endl; 
    }

  }

  /// @}

} //namespace lemon

#endif //LEMON_DIMACS_H