/* -*- C++ -*-

  * src/lemon/graph_reader.h - Part of LEMON, a generic C++ optimization library

  *

  * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

  * (Egervary Combinatorial Optimization Research Group, 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.

  *

  */

 ///\ingroup gio

 ///\file

 ///\brief Graph reader.

 #include <iostream>

 #include <sstream>

 #include <map>

 #include <vector>

 #include <memory>

 #include <lemon/error.h>

 /// \todo fix exceptions

 namespace lemon {

   // Exceptions

   class IOException {

   public:

     virtual string what() const = 0;

   };

   class DataFormatException : public IOException {

     std::string message;

   public:

     DataFormatException(const std::string& _message) 

       : message(_message) {}

     std::string what() const {

       return "DataFormatException: " + message; 

     }

   };

   template <typename _Exception>

   class StreamException : public _Exception {

   public:

     typedef _Exception Exception;

     StreamException(int _line, Exception _exception) 

       : line_num(_line), Exception(_exception) {}

     virtual int line() const {

       return line_num;

     }

     virtual std::string what() const {

       ostringstream os;

       os << Exception::what() << " in line " << line();

       return os.str();

     }

   private:

     int line_num;

   };  

   // Readers and ReaderTraits

   struct DefaultReaderTraits {

     template <typename _Value>

     struct Reader {

       typedef _Value Value;

       void read(std::istream& is, Value& value) {

 	if (!(is >> value)) 

 	  throw DataFormatException("Default Reader format exception");

       }

     };

     typedef Reader<std::string> DefaultReader;

   };

   class QuotedStringReader {

   public:

     typedef std::string Value;

     QuotedStringReader(bool _escaped = true) : escaped(_escaped) {}

     void read(std::istream& is, std::string& value) {

       char c;

       value.clear();

       is >> ws;

       if (!is.get(c) || c != '\"') throw DataFormatException("Quoted string format");

       while (is.get(c) && c != '\"') {

 	if (escaped && c == '\\') {

 	  value += readEscape(is);

 	} else {

 	  value += c;

 	}

       }

       if (!is) throw DataFormatException("Quoted string format");

     }

   private:

     static char readEscape(std::istream& is) {

       char c;

       switch (is.get(c), c) {

       case '\\':

 	return '\\';

       case '\"':

 	return '\"';

       case '\'':

 	return '\'';

       case '\?':

 	return '\?';

       case 'a':

 	return '\a';

       case 'b':

 	return '\b';

       case 'f':

 	return '\f';

       case 'n':

 	return '\n';

       case 'r':

 	return '\r';

       case 't':

 	return '\t';

       case 'v':

 	return '\v';

       case 'x':

 	{

 	  int code;

 	  if (!is.get(c) || !isHex(c)) throw DataFormatException("Escape format exception");

 	  else if (code = valueHex(c), !is.get(c) || !isHex(c)) is.putback(c);

 	  else code = code * 16 + valueHex(c);

 	  return code;

 	}

       default:

 	{

 	  int code;

 	  if (!isOct(c)) throw DataFormatException("Escape format exception");

 	  else if (code = valueOct(c), !is.get(c) || !isOct(c)) is.putback(c);

 	  else if (code = code * 8 + valueOct(c), !is.get(c) || !isOct(c)) is.putback(c);

 	  else code = code * 8 + valueOct(c);

 	  return code;

 	}	      

       } 

     }

     static bool isOct(char c) {

       return '0' <= c && c <='7'; 

     }

     static int valueOct(char c) {

       return c - '0';

     }

    static bool isHex(char c) {

       return ('0' <= c && c <= '9') || ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z'); 

     }

     static int valueHex(char c) {

       if ('0' <= c && c <= '9') return c - '0';

       if ('a' <= c && c <= 'z') return c - 'a' + 10;

       return c - 'A' + 10;

     }

     bool escaped;

   };

   // Graph reader

   template <typename _Graph, typename _ReaderTraits = DefaultReaderTraits> 

   class GraphReader {

   public:

     typedef _Graph Graph;

     typedef typename Graph::Node Node;

     typedef typename Graph::Edge Edge;

     typedef _ReaderTraits ReaderTraits;

     typedef typename ReaderTraits::DefaultReader DefaultReader;

     GraphReader(std::istream& _is, Graph& _graph, const DefaultReader& _reader = DefaultReader()) 

       : is(_is), graph(_graph), nodeSkipper(_reader), edgeSkipper(_reader) {}

     ~GraphReader() {

       for (typename NodeMapReaders::iterator it = node_map_readers.begin(); it != node_map_readers.end(); ++it) {

 	delete it->second;

       }

       for (typename EdgeMapReaders::iterator it = edge_map_readers.begin(); it != edge_map_readers.end(); ++it) {

 	delete it->second;

       }

     }

     // Node map rules

     template <typename Map>

     GraphReader& readNodeMap(std::string name, Map& map) {

       return readNodeMap<typename ReaderTraits::template Reader<typename Map::Value>, Map>(name, map);

     }

     template <typename Reader, typename Map>

     GraphReader& readNodeMap(std::string name, Map& map, const Reader& reader = Reader()) {

       if (node_map_readers.find(name) != node_map_readers.end()) {

 	throw Exception() << "Multiple read rule for node map: " << name;

       }

       node_map_readers.insert(make_pair(name, new MapReader<Node, Map, Reader>(map, reader)));

       return *this;

     }

     template <typename Reader>

     GraphReader& skipNodeMap(std::string name, const Reader& reader = Reader()) {

       if (node_map_readers.find(name) != node_map_readers.end()) {

 	throw Exception() << "Multiple read rule for node map: " << name;

       }

       node_map_readers.insert(make_pair(name, new SkipReader<Node, Reader>(reader)));

       return *this;

     }

     // Edge map rules

     template <typename Map>

     GraphReader& readEdgeMap(std::string name, Map& map) { 

       return readEdgeMap<typename ReaderTraits::template Reader<typename Map::Value>, Map>(name, map);

     }

     template <typename Reader, typename Map>

     GraphReader& readEdgeMap(std::string name, Map& map, const Reader& reader = Reader()) {

       if (edge_map_readers.find(name) != edge_map_readers.end()) {

 	throw Exception() << "Multiple read rule for edge map: " << name;

       }

       edge_map_readers.insert(make_pair(name, new MapReader<Edge, Map, Reader>(map, reader)));

       return *this;

     }

     template <typename Reader>

     GraphReader& skipEdgeMap(std::string name, const Reader& reader = Reader()) {

       if (edge_map_readers.find(name) != edge_map_readers.end()) {

 	throw Exception() << "Multiple read rule for edge map: " << name;

       }

       edge_map_readers.insert(make_pair(name, new SkipReader<Edge, Reader>(reader)));

       return *this;

     }

     // Node rules

     GraphReader& readNode(std::string name, Node& node) {

       if (node_readers.find(name) != node_readers.end()) {

 	throw Exception() << "Multiple read rule for node";

       }

       node_readers.insert(make_pair(name, &node));

     }

     // Edge rules

     GraphReader& readEdge(std::string name, Edge& edge) {

       if (edge_readers.find(name) != edge_readers.end()) {

 	throw Exception() << "Multiple read rule for edge";

       }

       edge_readers.insert(make_pair(name, &edge));

     }

     void read() {

       int line_num = 0;

       std::auto_ptr<InverterBase<Node> > nodeInverter;

       std::auto_ptr<InverterBase<Edge> > edgeInverter;

       try {

 	std::string line = readNotEmptyLine(is, line_num);

 	if (line.find("@nodeset") == 0) {

 	  line = readNodeSet(line_num, nodeInverter);

 	} 

 	if (line.find("@edgeset") == 0) {

 	  line = readEdgeSet(line_num, edgeInverter, nodeInverter);

 	}

 	if (line.find("@nodes") == 0) {

 	  line = readNodes(line_num, nodeInverter);

 	}

 	if (line.find("@edges") == 0) {

 	  line = readEdges(line_num, edgeInverter);

 	}

 	if (line.find("@end") != 0) {

 	  throw DataFormatException("Invalid control sequence: " + line);

 	}

       } catch (DataFormatException e) {

 	throw StreamException<DataFormatException>(line_num, e);

       }

     }

   private:

     template <typename Item> class InverterBase;

     std::string readNodeSet(int& line_num, auto_ptr<InverterBase<Node> > & nodeInverter) {

       std::vector<ReaderBase<Node>* > index;

       {

 	std::string line = readNotEmptyLine(is, line_num);    

 	std::string id;

 	std::istringstream ls(line);	

 	while (ls >> id) {

 	  if (id[0] == '#') break;

 	  typename NodeMapReaders::iterator it = node_map_readers.find(id);

 	  if (it != node_map_readers.end()) {

 	    index.push_back(it->second);

 	    node_map_readers.erase(it);

 	  } else {

 	    index.push_back(&nodeSkipper);

 	  }

 	}

       }

       if (index.size() == 0) {

 	throw DataFormatException("No node map found");

       }

       nodeInverter = auto_ptr<InverterBase<Node> >(index[0]->getInverter());

       std::string line;

       while (line = readNotEmptyLine(is, line_num), line[0] != '@') {

 	Node node = graph.addNode();

 	std::istringstream ls(line);

 	nodeInverter->read(ls, node);

 	for (int i = 1; i < index.size(); ++i) {

 	  index[i]->read(ls, node);

 	}

       }

       return line;

     }

     std::string readEdgeSet(int& line_num, 

 		     auto_ptr<InverterBase<Edge> > & edgeInverter, auto_ptr<InverterBase<Node> > & nodeInverter) {

       std::vector<ReaderBase<Edge>*> index;

       {

 	std::string line = readNotEmptyLine(is, line_num);    

 	std::string id;

 	std::istringstream ls(line);	

 	while (ls >> id) {

 	  if (id[0] == '#') break;

 	  typename EdgeMapReaders::iterator it = edge_map_readers.find(id);

 	  if (it != edge_map_readers.end()) {

 	    index.push_back(it->second);

 	    edge_map_readers.erase(it);

 	  } else {

 	    index.push_back(&edgeSkipper);

 	  }

 	}

       }

       if (index.size() == 0) {

 	throw DataFormatException("No edge map found");

       }

       edgeInverter = auto_ptr<InverterBase<Edge> >(index[0]->getInverter());

       std::string line;

       while (line = readNotEmptyLine(is, line_num), line[0] != '@') {	

 	std::istringstream ls(line);

 	Node source = nodeInverter->read(ls);

 	Node target = nodeInverter->read(ls);

 	Edge edge = graph.addEdge(source, target);

 	edgeInverter->read(ls, edge);

 	for (int i = 1; i < index.size(); ++i) {

 	  index[i]->read(ls, edge);

 	}

       }      

       return line;

     }

     std::string readNodes(int& line_num, auto_ptr<InverterBase<Node> >& nodeInverter) {

       std::string line;

       while (line = readNotEmptyLine(is, line_num), line[0] != '@') {

 	std::istringstream ls(line);

 	std::string name;

 	ls >> name;

 	typename NodeReaders::iterator it = node_readers.find(name);

 	if (it != node_readers.end()) {

 	  *(it -> second) = nodeInverter->read(ls);

 	} 

       }        

       return line;

     }

     std::string readEdges(int& line_num, auto_ptr<InverterBase<Edge> >& edgeInverter) {

       std::string line;

       while (line = readNotEmptyLine(is, line_num), line[0] != '@') {

 	std::istringstream ls(line);

 	std::string name;

 	ls >> name;

 	typename EdgeReaders::iterator it = edge_readers.find(name);

 	if (it != edge_readers.end()) {

 	  *(it -> second) = edgeInverter->read(ls);

 	} 

       }        

       return line;    

     }

     std::string readNotEmptyLine(std::istream& is, int& line_num) {

       std::string line;

       while (++line_num, getline(is, line)) {	

 	int vi = line.find_first_not_of(" \t");

 	if (vi != string::npos && line[vi] != '#') {

 	  return line.substr(vi);

 	}

       }

       throw DataFormatException("End of stream");

     }

     // Inverters store and give back the Item from the id,

     // and may put the ids into a map.

     template <typename _Item>

     class InverterBase {

     public:

       typedef _Item Item;

       virtual void read(std::istream&, const Item&) = 0;

       virtual Item read(std::istream&) = 0;

     };

     template <typename _Item, typename _Map, typename _Reader>

     class MapReaderInverter : public InverterBase<_Item> {

     public:

       typedef _Item Item;

       typedef _Reader Reader;

       typedef typename Reader::Value Value;

       typedef _Map Map;

       typedef std::map<Value, Item> Inverse;

       Map& map;

       Reader reader;

       Inverse inverse;

       MapReaderInverter(Map& _map, const Reader& _reader) 

 	: map(_map), reader(_reader) {}

       virtual void read(std::istream& is, const Item& item) {

 	Value value;

 	reader.read(is, value);

 	map.set(item, value);

 	typename Inverse::iterator it = inverse.find(value);

 	if (it == inverse.end()) {

 	  inverse.insert(make_pair(value, item));

 	} else {

 	  throw DataFormatException("Multiple ID occurence");

 	}

       }

       virtual Item read(std::istream& is) {

 	Value value;

 	reader.read(is, value);	

 	typename Inverse::const_iterator it = inverse.find(value);

 	if (it != inverse.end()) {

 	  return it->second;

 	} else {

 	  throw DataFormatException("Invalid ID");

 	}

       }      

     };

     template <typename _Item, typename _Reader>

     class SkipReaderInverter : public InverterBase<_Item> {

     public:

       typedef _Item Item;

       typedef _Reader Reader;

       typedef typename Reader::Value Value;

       typedef std::map<Value, Item> Inverse;

       Reader reader;

       SkipReaderInverter(const Reader& _reader) 

 	: reader(_reader) {}

       virtual void read(std::istream& is, const Item& item) {

 	Value value;

 	reader.read(is, value);

 	typename Inverse::iterator it = inverse.find(value);

 	if (it == inverse.end()) {

 	  inverse.insert(make_pair(value, item));

 	} else {

 	  throw DataFormatException("Multiple ID occurence");

 	}

       }

       virtual Item read(std::istream& is) {

 	Value value;

 	reader.read(is, value);	

 	typename Inverse::const_iterator it = inverse.find(value);

 	if (it != inverse.end()) {

 	  return it->second;

 	} else {

 	  throw DataFormatException("Invalid ID");

 	}

       }      

     private:

       Inverse inverse;

     };

     // Readers

     template <typename _Item>    

     class ReaderBase {

     public:

       typedef _Item Item;

       virtual void read(std::istream& is, const Item& item) = 0;

       virtual InverterBase<_Item>* getInverter() = 0;

     };

     template <typename _Item, typename _Map, typename _Reader>

     class MapReader : public ReaderBase<_Item> {

     public:

       typedef _Map Map;

       typedef _Reader Reader;

       typedef typename Reader::Value Value;

       typedef _Item Item;

       Map& map;

       Reader reader;

       MapReader(Map& _map, const Reader& _reader) 

 	: map(_map), reader(_reader) {}

       virtual void read(std::istream& is, const Item& item) {

 	Value value;

 	reader.read(is, value);

 	map.set(item, value);

       }

       virtual InverterBase<_Item>* getInverter() {

 	return new MapReaderInverter<Item, Map, Reader>(map, reader);

       }

     };

     template <typename _Item, typename _Reader>

     class SkipReader : public ReaderBase<_Item> {

     public:

       typedef _Reader Reader;

       typedef typename Reader::Value Value;

       typedef _Item Item;

       Reader reader;

       SkipReader(const Reader& _reader) : reader(_reader) {}

       virtual void read(std::istream& is, const Item& item) {

 	Value value;

 	reader.read(is, value);

       }      

       virtual InverterBase<Item>* getInverter() {

 	return new SkipReaderInverter<Item, Reader>(reader);

       }

     };

     typedef std::map<std::string, ReaderBase<Node>*> NodeMapReaders;

     NodeMapReaders node_map_readers;

     typedef std::map<std::string, ReaderBase<Edge>*> EdgeMapReaders;

     EdgeMapReaders edge_map_readers;

     typedef std::map<std::string, Node*> NodeReaders;

     NodeReaders node_readers;

     typedef std::map<std::string, Edge*> EdgeReaders;

     EdgeReaders edge_readers;

     std::istream& is;

     Graph& graph;

     SkipReader<Node, DefaultReader> nodeSkipper;

     SkipReader<Edge, DefaultReader> edgeSkipper;

   };

 }