#include "../config/pathan_config.h"
/*
 * Copyright (c) 2001, DecisionSoft Limited All rights reserved.
 * Please see LICENSE.TXT for more information.
 */

#include <pathan/operators/Union.hpp>

#include <pathan/Sequence.hpp>
#include <pathan/Node.hpp>
#include <pathan/exceptions/XPath2ErrorException.hpp>
#include <pathan/DynamicContext.hpp>

/*static*/ const XMLCh Union::name[]={ XERCES_CPP_NAMESPACE_QUALIFIER chLatin_u, XERCES_CPP_NAMESPACE_QUALIFIER chLatin_n, XERCES_CPP_NAMESPACE_QUALIFIER chLatin_i, XERCES_CPP_NAMESPACE_QUALIFIER chLatin_o, XERCES_CPP_NAMESPACE_QUALIFIER chLatin_n, XERCES_CPP_NAMESPACE_QUALIFIER chNull };

Union::Union(const VectorOfDataItems &args, XPath2MemoryManager* memMgr)
  : DataItemOperator(name, args, memMgr)
{
}

Sequence Union::collapseTreeInternal(DynamicContext* context, int flags) const
{
	Sequence param1 = _args[0]->collapseTree(context);
	if(!checkSequenceIsNodes(param1)) {
		DSLthrow(XPath2ErrorException,X("Union::collapseTreeInternal"), X("The operator 'union' has been called with a parameter that is not just nodes"));
	}
	Sequence param2 = _args[1]->collapseTree(context);
	if(!checkSequenceIsNodes(param2)) {
		DSLthrow(XPath2ErrorException,X("Union::collapseTreeInternal"), X("The operator 'union' has been called with a parameter that is not just nodes"));
	}

  //Now let's go through each element in the second list, and if it isn't already
  //in the first list, then add it to the first list
  for(Sequence::iterator secondIter = param2.begin(); secondIter != param2.end(); secondIter++) {
    bool toAdd = true;
    for(Sequence::iterator firstIter = param1.begin(); firstIter != param1.end(); firstIter++) {

      //If we see this element then set toAdd to false, and exit
      if(((const Node*)*firstIter)->equals((const Node*)*secondIter)) {
        toAdd = false;
        break;
      }
    }

    //Add the element if it isn't already in the list
    if(toAdd == true) {
      param1.addItem(*secondIter);
    }
  }

  //Sort the nodes into document order
  if(!(flags & DataItem::UNORDERED))
    param1.sortIntoDocumentOrder();
  return param1;
}