/*
 * Ext JS Library 2.2
 * Copyright(c) 2006-2008, Ext JS, LLC.
 * licensing@extjs.com
 * 
 * http://extjs.com/license
 */

/**
 * @class Ext.ux.XmlTreeLoader
 * @extends Ext.tree.TreeLoader
 * <p>A TreeLoader that can convert an XML document into a hierarchy of {@link Ext.tree.TreeNode}s.
 * Any text value included as a text node in the XML will be added to the parent node as an attribute
 * called <tt>innerText</tt>.  Also, the tag name of each XML node will be added to the tree node as
 * an attribute called <tt>tagName</tt>.</p>
 * <p>By default, this class expects that your source XML will provide the necessary attributes on each 
 * node as expected by the {@link Ext.tree.TreePanel} to display and load properly.  However, you can
 * provide your own custom processing of node attributes by overriding the {@link #processNode} method
 * and modifying the attributes as needed before they are used to create the associated TreeNode.</p>
 * @constructor
 * Creates a new XmlTreeloader.
 * @param {Object} config A config object containing config properties.
 */
Ext.ux.XmlTreeLoader = Ext.extend(Ext.tree.TreeLoader, {
	/**
	 * @property  XML_NODE_ELEMENT
	 * XML element node (value 1, read-only)
	 * @type Number
	 */
	XML_NODE_ELEMENT : 1,
	/**
	 * @property  XML_NODE_TEXT
	 * XML text node (value 3, read-only)
	 * @type Number
	 */
	XML_NODE_TEXT : 3,

	// private override
	processResponse : function(response, node, callback){
		var xmlData = response.responseXML;
		var root = xmlData.documentElement || xmlData;

		try{
			node.beginUpdate();
			node.appendChild(this.parseXml(root));
			node.endUpdate();

			if(typeof callback == "function"){
				callback(this, node);
			}
		}catch(e){
			this.handleFailure(response);
		}
	},

	// private
	parseXml : function(node) {
		var nodes = [];
		Ext.each(node.childNodes, function(n){
			if(n.nodeType == this.XML_NODE_ELEMENT){
				var treeNode = this.createNode(n);
				if(n.childNodes.length > 0){
					var child = this.parseXml(n);
					if(typeof child == 'string'){
						treeNode.attributes.innerText = child;
					}else{
						treeNode.appendChild(child);
					}
				}
				nodes.push(treeNode);
			}
			else if(n.nodeType == this.XML_NODE_TEXT){
				var text = n.nodeValue.trim();
				if(text.length > 0){
					return nodes = text;
				}
			}
		}, this);

		return nodes;
	},

	// private override
	createNode : function(node){
		var attr = {
			tagName: node.tagName
		};

		Ext.each(node.attributes, function(a){
			attr[a.nodeName] = a.nodeValue;
		});

		this.processAttributes(attr);

		return Ext.ux.XmlTreeLoader.superclass.createNode.call(this, attr);
	},

	/*
	 * Template method intended to be overridden by subclasses that need to provide
	 * custom attribute processing prior to the creation of each TreeNode.  This method
	 * will be passed a config object containing existing TreeNode attribute name/value
	 * pairs which can be modified as needed directly (no need to return the object).
	 */
	processAttributes: Ext.emptyFn
});