// -*- c++ -*-

#ifndef HUGO_DIMACS_H

#define HUGO_DIMACS_H

#include <iostream>

#include <string>

#include <vector>

#include <hugo/maps.h>

/// \file

/// \brief Dimacs file format reader.

namespace hugo {

  /// Dimacs flow file format reader function.

  /// This function reads a flow instance from dimacs flow format.

  /// At the beginning \c g is cleared by \c g.clear().

  /// If the data coming from \c is is a max flow problem instance, then 

  /// \c s and \c t will be respectively the source and target nodes 

  /// and \c capacity will contain the edge capacities.

  /// If the data is a shortest path problem instance then \c s will be the 

  /// source node and \c capacity will contain the edge lengths.

  ///

  ///\author Marton Makai

  template<typename Graph, typename CapacityMap>

  void readDimacsMaxFlow(std::istream& is, Graph &g, 

			 typename Graph::Node &s, typename Graph::Node &t, CapacityMap& capacity) {

    g.clear();

    int cap;

    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") { //max flow problem

	  is >> i >> d;

	  getline(is, str);

	  if (d=='s') s=nodes[i];

	  if (d=='t') t=nodes[i];

	}

	break;

      case 'a':

	is >> i >> j >> cap;

	getline(is, str);

	e=g.addEdge(nodes[i], nodes[j]);

	capacity.update();

	capacity.set(e, cap);

	break;

      }

    }

  }

  /// matching problem

  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);

  }

  /// sg problem

  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);

  }

  /// shortest path problem

  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);

  }

  /// max flow problem

  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);

  }

  /// min cost flow problem

  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::ValueType _cap;

    typename CostMap::ValueType _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 == "mat" ) {

	  is >> i >> j;

	  getline(is, str);

	  g.addEdge(nodes[i], nodes[j]);

	}

	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);

	}

	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);

	}

	break;

      }

    }

  }

  /// 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;

    NodeIt v;

    for(g.first(v); g.valid(v); g.next(v)) {

      nodes.set(v, i);

      ++i;

    }    

    os << "p mat " << g.nodeNum() << " " << g.edgeNum() << std::endl;

    EdgeIt e;

    for(g.first(e); g.valid(e); g.next(e)) {

      os << "a " << nodes[g.tail(e)] << " " << nodes[g.head(e)] << std::endl; 

    }

  }

} //namespace hugo

#endif //HUGO_DIMACS_H