/* -*- C++ -*-
 * gui/xml.h - Part of LEMON, a generic C++ optimization library
 *
 * Copyright (C) 2006 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.
 *
 */

#include <iostream>
#include <string>
#include <vector>
#include <list>
#include <map>
#include <lemon/error.h>
#include <lemon/xy.h>

namespace lemon {

  class XmlIo 
  {
    bool _writeMode;
  public:
    ///Check if XmlIo is in write mode.
    bool write() { return _writeMode;}
    ///Check if XmlIo is in read mode.
    bool read() { return !_writeMode;}

    std::ostream& os;
    int level;
    
  protected:
    void indent(int level) {
      os << std::endl;
      for(int i=0;i<level;i++) os << ' ';
    }
    void tag(const std::string &_tag) {
      os << '<' << _tag << '>';
    }
    void etag(const std::string &_tag) {
      os << "</" << _tag << '>';
    }
    void itag(const std::string &_tag) { indent();tag(_tag); }
    void ietag(const std::string &_tag) { indent();etag(_tag); }

    void beginTag(const std::string &_tag) {
      itag(_tag);
      level++;
    }
    void endTag(const std::string &_tag) {
      level--;
      ietag(_tag);
    }

  public:
    ///Indent the line according to its level.

    ///\warning It can only be used in write mode.
    ///
    void indent()
    {
      if(write())
	if(level>=0) indent(level);
	else level=0;
      else throw LogicError();	
    }
  
    ///Read/write a tag
  
    ///Read/write a tag.
    ///In write mode it does not start a new line.
    class ContTag
    {
      XmlIo &ix;
      const std::string _tag;
    public:
      ///\e
  
      ///\e
      ///
      ContTag(XmlIo &_ix,const std::string &_t) :
	ix(_ix), _tag(_t)
      {
	if(ix.write()) ix.tag(_tag);
	else ix.useTag(_tag);
      }
      ~ContTag() { 
	if(ix.write()) ix.etag(_tag);
	else if(!std::uncaught_exception()) ix.useTag('/'+_tag);      
      }
    };

    ///Read/write a tag
  
    ///Read/write a tag.
    ///The whole <foo> ... </foo> will be places in a single line.
    class LineTag
    {
      XmlIo &ix;
      const std::string _tag;
    public:
      ///\e
    
      ///\e
      ///
      LineTag(XmlIo &_ix,const std::string &_t) :
	ix(_ix), _tag(_t)
      {
	if(ix.write()) ix.itag(_tag);
	else ix.useTag(_tag);
      }
      ~LineTag() { 
	if(ix.write()) ix.etag(_tag);
	else if(!std::uncaught_exception()) ix.useTag('/'+_tag);
      }
    };

    ///Read/write a tag
  
    ///Read/write a tag.
    ///
    class Tag
    {
      XmlIo &ix;
      const std::string _tag;
    public:
      ///\e
  
      ///\e
      ///
      Tag(XmlIo &_ix,const std::string &_t) :
	ix(_ix), _tag(_t)
      {
	if(ix.write()) ix.beginTag(_tag);
	else ix.useTag(_tag);
      }
      ~Tag() {
	if(ix.write()) ix.endTag(_tag);
	else if(!std::uncaught_exception()) ix.useTag('/'+_tag);
      }
    };

  private:
    std::istream& is;
    std::string next_tag;
    int line_number;

    void skipWhiteSpaces()
    {
      if(write()) throw LogicError();
      {
	char c;
	while (is.get(c) && std::isspace(c,is.getloc()))
	  if(c=='\n') line_number++;
	is.unget();
      }
    }
  protected:
    /// Use the next tag.

    ///\e
    ///
    void useTag() {next_tag.clear();}
  
    ///Use the next tag and check if it is equal with \c _tag
  
    ///\e
    ///
    void useTag(const std::string &_tag) {
      if(nextTag()==_tag) useTag();
      else throw DataFormatError("",line_number,"Unexpected token name");
    }
  public:
    ///Return the next tag (if a tag follows on the stream).
  
    ///\warning It can only be used in read mode.
    ///
    const std::string &nextTag() 
    {
      if(write()) throw LogicError();
      else if(next_tag.empty()) {
	char c;
	skipWhiteSpaces();
	if(!is.get(c) || c!='<')
	  throw DataFormatError("",line_number,"Bad format");
	next_tag.clear();
	while (is.get(c) && c!='>') next_tag.push_back(c);
	if(c!='>')
	  throw DataFormatError("",line_number,"Bad format");
      }
      return next_tag;
    }

    /**********************************************************************/


    ///\e
  
    ///\e
    ///
    XmlIo(std::ostream& _os) : _writeMode(true), os(_os),
			       level(-1),
			       is(*(std::istream*)(NULL)) {}
    ///\e
    ///
    XmlIo(std::istream& _is) : _writeMode(false),
			       os(*(std::ostream*)(NULL)), is(_is),
			       line_number(1) {}

    ~XmlIo() { if(write()) os<< std::endl; }
  


    XmlIo &operator()(const int &v) 
    { 
      if(write()) os << v;
      else {
	skipWhiteSpaces();
	if(!(is >> const_cast<int &>(v))) 
	  throw DataFormatError("",line_number,"Not an 'int'");
      }
      return *this;
    }
    XmlIo &operator()(const double &v) 
    {
      if(write()) os << v;
      else {
	skipWhiteSpaces();
	if(!(is >> const_cast<double &>(v))) 
	  throw DataFormatError("",line_number,"Not an 'double'");
      }
      return *this;
    }
    XmlIo &operator()(const std::string &v)
    {
      if(write())
	for(std::string::const_iterator i=v.begin();i!=v.end();++i)
	  switch(*i) {
	  case '\\':
	    os << "\\\\";
	    break;
	  case '<':
	    os << "\\<";
	    break;
	  case '&':
	    os << "\\&";
	    break;
	  case '\n':
	    os << "\\n";
	    break;
	  default:
	    os<<*i;
	    break;
	  }
      else {
	std::string &w = const_cast<std::string &>(v);
	w.clear();
	char c;
	while (is.get(c) && c!='<')
	  if(c=='\\')
	    if(!is.get(c))
	      throw DataFormatError("",line_number,"Bad string");
	    else switch(c) {
	    case 'n':
	      w.push_back('\n');
	      break;
	    default:
	      w.push_back(c);
	      break;
	    }
	  else {
	    if(c=='\n') line_number++;
	    w.push_back(c);
	  }
	if(c!='<')
	  throw DataFormatError("",line_number,"Unexpected eof");
	is.unget();
      }
      return *this;
    }


    XmlIo &operator()(const std::string &_tag,const int &v) 
    { 
      LineTag t(*this,_tag);
      (*this)(v);
      return *this;
    }
    XmlIo &operator()(const std::string &_tag,const double &v) 
    {
      LineTag t(*this,_tag);
      (*this)(v);
      return *this;
    }
    XmlIo &operator()(const std::string &_tag,const std::string &v)
    {
      LineTag t(*this,_tag);
      (*this)(v);
      return *this;
    }
    ///\e
  
    ///\e
    ///
    template<class V>
    XmlIo &operator()(const std::string &_tag,const V &v)
    {
      Tag t(*this,_tag);
      xml(*this,const_cast<V &>(v));
      return *this;
    }
    ///\e
  
    ///\e
    ///
    template<class V>
    XmlIo &operator()(const V &v)
    {
      xml(*this,const_cast<V &>(v));
      return *this;
    }
    };

  //////////////////////////////////////////////////////////////////////
  //////////////////////////////////////////////////////////////////////

  ///\e
  
  ///\relates XmlIo
  ///
  template<class A>
  void xml(XmlIo &x,std::auto_ptr<A> &v)
  {
    if(x.write()) v=new A;
    x(*v);
  }
  
  ///\e
  
  ///\relates XmlIo
  ///
  template<class A,class B>
  void xml(XmlIo &x,std::pair<A,B> &v)
  {
    x("first",v.first);
    x("second",v.second);
  }

  ///\e
  
  ///\relates XmlIo
  ///
  template<class T>
  void xml(XmlIo &x,std::list<T> &v)
  {
    if(x.write())
      for(typename std::list<T>::const_iterator it=v.begin();
	  it!=v.end();++it) x("item",*it);
    else while(x.nextTag()=="item")
      {
	v.push_back(T());
	x("item",v.back());
      }
  }
  ///\e
  
  ///\relates XmlIo
  ///
  template<class T>
  void xml(XmlIo &x,std::vector<T> &v)
  {
    if(x.write())
      for(typename std::vector<T>::const_iterator it=v.begin();
	  it!=v.end();++it) x("item",*it);
    else while(x.nextTag()=="item")
      {
	v.push_back(T());
	x("item",v.back());      
      }
  }

  ///\e
  
  ///\relates XmlIo
  ///
  template<class K,class V>
  void xml(XmlIo &x,std::map<K,V> &v)
  {
    if(x.write()) 
      for(typename std::map<K,V>::const_iterator it=v.begin();
	  it!=v.end();++it) x("item",*it);
    else while(x.nextTag()=="item")
      {
	typename std::map<K,V>::value_type it;
	x("item",it);
	v.insert(it);
      }
  }

  ///\e
  
  ///\relates XmlIo
  ///
  template<class T>
  void xml(XmlIo &x,lemon::xy<T> &v)
  {
    { XmlIo::LineTag t(x,"x"); x(v.x); }
    { XmlIo::ContTag t(x,"y"); x(v.y); }
  }

  ///\e
  
  ///\relates XmlIo
  ///
  template<class T>
  void xml(XmlIo &x,lemon::BoundingBox<T> &v)
  {
    if(x.write()) {
      if(!v.empty()) {
	x("point",v.bottomLeft());
	if(v.bottomLeft()!=v.topRight()) x("point",v.topRight());
      }
    }
    else {
      v.clear();
      while(x.nextTag()=="point") {
	lemon::xy<T> co;
	x("point",co);
	v.add(co);
      }
    }
  }
  
}