#include <libxml++/libxml++.h>
#include <cassert>
#include <iostream>

void print_indentation(unsigned int indentation)
{
     for(unsigned int i = 0; i < indentation; ++i)
	  std::cout << " ";
}



//! get child element by id
/*!
  \return pointer to element having id or null on error
  \todo find libxmlpp pendant
*/
const xmlpp::Element* get_element_by_id(const xmlpp::Element* element, const std::string &id)
{
     const xmlpp::Attribute* cid = element->get_attribute("id");
     if ( cid && ( cid->get_value() == id)) return element;

     //Recurse through child nodes:
     xmlpp::Node::NodeList list = element->get_children();
     for(xmlpp::Node::NodeList::iterator iter = list.begin(); iter != list.end(); ++iter)
     {
	  const xmlpp::Element* element = dynamic_cast<const xmlpp::Element*>(*iter);
	  if (element) {
	       const xmlpp::Element* match = get_element_by_id(element, id);
	       if (match) return match;
	  }
     }
     return NULL;
}

//! get namespace by id
/*!
  \return namespace name or empty string on error
*/
std::string get_namespace(const xmlpp::Element* root, const std::string &id)
{
     std::string error;
     const xmlpp::Element* element(get_element_by_id(root, id));
     if ((!element)||(!element->get_attribute("name"))) return error;
     return element->get_attribute("name")->get_value();
}

//! get type by id
/*!
  \return type name or empty string on error
*/
std::string get_type(const xmlpp::Element* root, const std::string &id)
{
     std::string error;
     const xmlpp::Element* element(get_element_by_id(root, id));
     if (!element) return error;

     // TODO: not yet complete
     // if we recurse - when do we stop?
     // if it is a typedef? yes? (hmm if the typedef is in the file parsed this will not work)
     std::string tag(element->get_name());
     if (tag=="ReferenceType") {
	  assert(element->get_attribute("type"));
	  std::string ret(get_type(root, element->get_attribute("type")->get_value()));
	  if (ret==error) return error;
	  return ret+"&";
     }else if (tag=="CvQualifiedType") {
	  assert(element->get_attribute("type"));
	  std::string ret(get_type(root, element->get_attribute("type")->get_value()));
	  if (ret==error) return error;
	  return std::string("const ")+ret;
     }

     assert(element->get_attribute("name"));
     assert(element->get_attribute("context"));
     return get_namespace(root, element->get_attribute("context")->get_value())+"::"+element->get_attribute("name")->get_value();
}

void parse_function(const xmlpp::Element* root, const xmlpp::Node* node, unsigned int indentation = 0) {
     const xmlpp::Element* element = dynamic_cast<const xmlpp::Element*>(node);
     if (!element) return;

     const xmlpp::Attribute* attributes = element->get_attribute("attributes");
     const xmlpp::Attribute* name = element->get_attribute("name");
     const xmlpp::Attribute* returns = element->get_attribute("returns");
     if ((!attributes)||(!name)||(!returns)) return;

     // check wether the function is marked (TODO: improve)
     if (attributes->get_value().find("gccxml(libt2n")==std::string::npos) return;

     // TODO: extract command group
     // something like: sed 's,gccxml(libt2n-\([a-z]*}),\1,'

     // we need the return type
     std::string ret_type(get_type(root, returns->get_value()));

     // and the argument types
     typedef std::map<std::string, std::string> Args;
     Args  args;

     xmlpp::Node::NodeList list = node->get_children("Argument");
     for(xmlpp::Node::NodeList::iterator iter = list.begin(); iter != list.end(); ++iter)
     {
	  const xmlpp::Element* arg = dynamic_cast<const xmlpp::Element*>(*iter);
	  if ( arg ) {
	       assert(arg->get_name() == "Argument");
	       assert(arg->get_attribute("name"));
	       assert(arg->get_attribute("type"));
	       assert(args.find(arg->get_attribute("name")->get_value())==args.end());
	       args[arg->get_attribute("name")->get_value()]=get_type(root, arg->get_attribute("type")->get_value());
	  }
     }

     std::cerr << "Found marked Function: " << ret_type << " " << name->get_value() << "(";
     for (Args::const_iterator it=args.begin();it!=args.end();++it) {
	  if (it!=args.begin()) std::cerr << ", ";
	  std::cerr << it->second << " " << it->first;
     }
     std::cerr << ");" << std::endl;
}

void print_node(const xmlpp::Element* root, const xmlpp::Node* node = NULL, unsigned int indentation = 0)
{
     if (!node) node=root;
     std::cout << std::endl; //Separate nodes by an empty line.
  
     const xmlpp::ContentNode* nodeContent = dynamic_cast<const xmlpp::ContentNode*>(node);
     const xmlpp::TextNode* nodeText = dynamic_cast<const xmlpp::TextNode*>(node);
     const xmlpp::CommentNode* nodeComment = dynamic_cast<const xmlpp::CommentNode*>(node);

     if(nodeText && nodeText->is_white_space()) //Let's ignore the indenting - you don't always want to do this.
	  return;
    
     std::string nodename = node->get_name();

     if(!nodeText && !nodeComment && !nodename.empty()) //Let's not say "name: text".
     {
	  print_indentation(indentation);
	  //    std::cout << "Node name = " << node->get_name() << std::endl;
	  //    std::cout << "Node name = " << nodename << std::endl;
	  if (node->get_name() == "Function") {
	       parse_function(root, node, indentation);
	  }
     }
     else if(nodeText) //Let's say when it's text. - e.g. let's say what that white space is.
     {
	  print_indentation(indentation);
	  std::cout << "Text Node" << std::endl;
     }

     //Treat the various node types differently: 
     if(nodeText)
     {
	  print_indentation(indentation);
	  std::cout << "text = \"" << nodeText->get_content() << "\"" << std::endl;
     }
     else if(nodeComment)
     {
	  print_indentation(indentation);
	  std::cout << "comment = " << nodeComment->get_content() << std::endl;
     }
     else if(nodeContent)
     {
	  print_indentation(indentation);
	  std::cout << "content = " << nodeContent->get_content() << std::endl;
     }
     else if(const xmlpp::Element* nodeElement = dynamic_cast<const xmlpp::Element*>(node))
     {
	  //A normal Element node:

	  //line() works only for ElementNodes.
	  print_indentation(indentation);
	  std::cout << "     line = " << node->get_line() << std::endl;

	  //Print attributes:
	  const xmlpp::Element::AttributeList& attributes = nodeElement->get_attributes();
	  for(xmlpp::Element::AttributeList::const_iterator iter = attributes.begin(); iter != attributes.end(); ++iter)
	  {
	       const xmlpp::Attribute* attribute = *iter;
	       print_indentation(indentation);
	       std::cout << "  Attribute " << attribute->get_name() << " = " << attribute->get_value() << std::endl;
	  }

	  const xmlpp::Attribute* attribute = nodeElement->get_attribute("title");
	  if(attribute)
	  {
	       std::cout << "title found: =" << attribute->get_value() << std::endl;
      
	  }
     }
  
     if(!nodeContent)
     {
	  //Recurse through child nodes:
	  xmlpp::Node::NodeList list = node->get_children();
	  for(xmlpp::Node::NodeList::iterator iter = list.begin(); iter != list.end(); ++iter)
	  {
	       print_node(root, *iter, indentation + 2); //recursive
	  }
     }
}

int main(int argc, char* argv[])
{
     std::string filepath;
     if(argc > 1 )
	  filepath = argv[1]; //Allow the user to specify a different XML file to parse.
     else
	  filepath = "example.xml";
  
     try
     {
	  xmlpp::DomParser parser;
	  //    parser.set_validate();
	  parser.set_substitute_entities(); //We just want the text to be resolved/unescaped automatically.
	  parser.parse_file(filepath);
	  if(parser)
	  {
	       //Walk the tree:
	       const xmlpp::Node* pNode = parser.get_document()->get_root_node(); //deleted by DomParser.
	       const xmlpp::Element* root = dynamic_cast<const xmlpp::Element*>(pNode);
	       assert(root);
	       print_node(root);
	  }
     }
     catch(const std::exception& ex)
     {
	  std::cout << "Exception caught: " << ex.what() << std::endl;
     }

     return 0;
}