package cz.cuni.amis.pogamut.defcon.utils.quadtree;
   
   import java.util.Iterator;
   import java.util.LinkedList;
   import java.util.NoSuchElementException;
   
   /**
    * Allows user to iterate over
    * {@link cz.cuni.amis.pogamut.defcon.utils.quadtree.QuadTree}s, in a BFS
   * manner.
   * 
   * @author Radek 'Black_Hand' Pibil
   * 
   */
  public class QuadTreeBFSIterator implements Iterator<QuadTreeNode> {
  
  	private QuadTree tree;
  	private QuadTreeNode node = null;
  	private QuadTreeNode root = null;
  	private boolean finished = false;
  	private final LinkedList<QuadTreeNode> branching = new LinkedList<QuadTreeNode>();
  
  
  	public QuadTreeBFSIterator(QuadTree tree) {
  		if (tree == null)
  			throw new IllegalArgumentException("Tree cannot be null");
  
  		this.tree = tree;
  		this.root = tree.getRoot();
  		branching.addLast(root);
  	}
  
  	@Override
  	public boolean hasNext() {
  		return !branching.isEmpty();
  	}
  
  	@Override
  	public QuadTreeNode next() {
  		if (!hasNext())
  			throw new NoSuchElementException();
  
  		QuadTreeNode node = branching.pop();
  
  		if (node.getNodes() != null) {
  			for (QuadTreeNode child : node.getNodes()) {
  				branching.addLast(child);
  			}
  		}
  
  		return node;
  	}
  
  	@Override
  	public void remove() {
  		throw new UnsupportedOperationException(
  				"QuadTreeIterator does not support remove() method.");
  	}
  
  }