package org.daisy.pipeline.nlp.calabash.impl;
   
   import java.util.ArrayList;
   import java.util.HashSet;
   import java.util.List;
   import java.util.Set;
   
   import net.sf.saxon.om.NodeInfo;
   import net.sf.saxon.s9api.QName;
  import net.sf.saxon.s9api.XdmNode;
  
  /**
   * This class keeps track of the duplicated nodes. Rather than maintaining a set
   * of all the nodes created, it keeps under watch only those that might not have
   * been closed yet in the original document. The nodes' depth levels are used
   * for detecting when they are closed.
   */
  public class DuplicationManager {
  
  	private List<NodeInfo> mDuplicatedNodes;
  	private ArrayList<Set<NodeInfo>> mUnderWatch;
  
  	private boolean mForbidAnyDup;
  	private final static QName IDattr = new QName("id");
  
  	public DuplicationManager(boolean forbidAnyDup) {
  		mForbidAnyDup = forbidAnyDup;
  	}
  
  	public void onNewDocument() {
  		mDuplicatedNodes = new ArrayList<NodeInfo>();
  		mUnderWatch = new ArrayList<Set<NodeInfo>>();
  	}
  
  	public void onNewSection() {
  	}
  
  	public void onNewNode(XdmNode node, int level) {
  		if (!mForbidAnyDup && node.getAttributeValue(IDattr) == null)
  			return;
  
  		NodeInfo info = node.getUnderlyingNode();
  		for (Set<NodeInfo> watched : mUnderWatch)
  			if (watched.contains(info)) {
  				mDuplicatedNodes.add(info);
  				break;
  			}
  
  		if (mUnderWatch.size() > level)
  			mUnderWatch.subList(level + 1, mUnderWatch.size()).clear();
  		else
  			while (mUnderWatch.size() <= level)
  				mUnderWatch.add(new HashSet<NodeInfo>());
  		mUnderWatch.get(level).add(info);
  	}
  
  	//the result may contain multiple occurrences of the same node
  	public List<NodeInfo> getDuplicatedNodes() {
  		return mDuplicatedNodes;
  	}
  }