package com.mycompany.jsf.model;

import java.util.StringTokenizer;
import javax.faces.component.NamingContainer;

/**
 * This class represents a tree of nodes, used as the model for
 * the UITree component.
 *
 * @author Hans Bergsten, Gefion Software <hans@gefionsoftware.com>
 * @version 1.0
 */
public class TreeModel {
    private final static String SEPARATOR = 
	String.valueOf(NamingContainer.SEPARATOR_CHAR);

    private TreeNode root;
    private TreeNode currentNode;

    /**
     * Create a model with the provided TreeNode as the root.
     */
    public TreeModel(TreeNode root) {
	this.root = root;
    }

    /**
     * Returns the current node, or null if no node is selected.
     */
    public TreeNode getNode() {
	return currentNode;
    }

    /**
     * Selects the node matching the specified node ID, or deselects
     * the current node if the node ID is null. The node ID is a
     * colon-separated list of zero-based node indexes, e.g., the
     * node ID "0:0:1" represents the second subnode of the first
     * node under the root node.
     */
    public void setNodeId(String nodeId) {
	if (nodeId == null) {
	    currentNode = null;
	    return;
	}
	
	TreeNode node = root;
	StringBuffer sb = new StringBuffer();
	StringTokenizer st = 
	    new StringTokenizer(nodeId, SEPARATOR);

	// Trow away the root index
	sb.append(st.nextToken()).append(SEPARATOR);
	while (st.hasMoreTokens()) {
	    int nodeIndex = Integer.parseInt(st.nextToken());
	    sb.append(nodeIndex);
	    try {
		node = (TreeNode) node.getChildren().get(nodeIndex);
	    }
	    catch (IndexOutOfBoundsException e) {
		String msg = "Node node with ID " + sb.toString() +
		    ". Failed to parse " + nodeId;
		throw new IllegalArgumentException(msg);
	    }
	    sb.append(SEPARATOR);
	}
	currentNode = node;
    }
}