#ifndef XMLWRAP_H		// -*- c++ -*-
#define XMLWRAP_H
#include "stringutil.h"
#include <libxml++/libxml++.h>

/**
 * Wrap an xmlpp::Element for one-call loading / converting of typed values.
 * \note An ElementWrap keeps a reference to the Element.  That might be
 * dangerous.
 */
class ElementWrap {
public:
  ElementWrap(const std::string& filename, const xmlpp::Element& element)
    : filename_(filename), element_(element)
    {}
  ElementWrap(const ElementWrap& wrap, const xmlpp::Element& element)
    : filename_(wrap.filename_), element_(element)
    {}
 
  const xmlpp::Element& element() const { return element_; }
  std::string get_element_name() const { return element_.get_name(); }
  
  template<class C>
  C get_attribute(const std::string& name, const C& deflt = C()) const;

  template<class C>
  C get_required_attribute(const std::string& name) const;
  
  const xmlpp::Attribute* get_raw_attribute(const std::string& name) const {
    return element_.get_attribute(name);
  }
  
  std::string get_filename(const std::string& attrname) const;
  
private:
  const std::string filename_;
  const xmlpp::Element& element_;
};

// inline implementation of templates

template<class C>
inline C
ElementWrap::get_attribute(const std::string& name, const C& deflt) const {
  if(const xmlpp::Attribute* cols = element_.get_attribute(name))
    try {
      return to<C>(cols->get_value());
    } catch(const std::exception& err) {
      throw std::runtime_error(err.what() + std::string(", in ")
			       + get_element_name()
			       + " attribute " + name
			       + ", \"" + filename_ + "\"");
    }
  else
    return deflt;
}

template<class C>
inline C ElementWrap::get_required_attribute(const std::string& name) const {
  if(const xmlpp::Attribute* cols = element_.get_attribute(name))
    try {
      return to<C>(cols->get_value());
    } catch(const std::exception& err) {
      throw std::runtime_error(err.what() + std::string(", in ")
			       + get_element_name()
			       + " attribute " + name
			       + ", \"" + filename_ + "\"");
    }
  else
    throw std::runtime_error("Required attribute \"" + name +
			     "\" missing in <" + get_element_name() + ">");
}

#endif