/*
Copyright (c) 2003-2009, CKSource - Frederico Knabben. All rights reserved.
For licensing, see LICENSE.html or http://ckeditor.com/license
*/

/**
 * @fileOverview Defines the {@link CKEDITOR.xml} class, which represents a
 *		loaded XML document.
 */

/**
 * Represents a loaded XML document.
 * @constructor
 * @param {object|string} xmlObjectOrData A native XML (DOM document) object or
 *		a string containing the XML definition to be loaded.
 * @example
 * var xml = <b>new CKEDITOR.xml( '<books><book title="My Book" /></books>' )</b>;
 */
CKEDITOR.xml = function( xmlObjectOrData )
{
	var baseXml = null;

	if ( typeof xmlObjectOrData == 'object' )
		baseXml = xmlObjectOrData;
	else
	{
		if ( window.DOMParser )
			baseXml = (new DOMParser()).parseFromString( xmlObjectOrData || '', 'text/xml' );
		else if ( window.ActiveXObject )
		{
			try { baseXml = new ActiveXObject( 'MSXML2.DOMDocument' ); }
			catch(e)
			{
				try { baseXml = new ActiveXObject( 'Microsoft.XmlDom' ); } catch(e) {}
			}

			if ( baseXml )
			{
				baseXml.async = false;
				baseXml.resolveExternals = false;
				baseXml.validateOnParse = false;
				baseXml.loadXML( xmlObjectOrData || '' );
			}
		}
	}

	/**
	 * The native XML (DOM document) used by the class instance.
	 * @type object
	 * @example
	 */
	this.baseXml = baseXml;
};

CKEDITOR.xml.prototype =
{
	/**
	 * Get a single node from the XML document, based on a XPath query.
	 * @param {String} xpath The XPath query to execute.
	 * @param {Object} [contextNode] The XML DOM node to be used as the context
	 *		for the XPath query. The document root is used by default.
	 * @returns {Object} A XML node element or null if the query has no results.
	 * @example
	 * // Create the XML instance.
	 * var xml = new CKEDITOR.xml( '<list><item id="test1" /><item id="test2" /></list>' );
	 * // Get the first <item> node.
	 * var itemNode = <b>xml.selectSingleNode( 'list/item' )</b>;
	 * // Alert "item".
	 * alert( itemNode.nodeName );
	 */
	selectSingleNode : function( xpath, contextNode )
	{
		var baseXml = this.baseXml;

		if ( contextNode || ( contextNode = baseXml ) )
		{
			if ( CKEDITOR.env.ie || contextNode.selectSingleNode )	// IE
				return contextNode.selectSingleNode( xpath );
			else if ( baseXml.evaluate )							// Others
			{
				var result = baseXml.evaluate( xpath, contextNode, null, 9, null);
				return ( result && result.singleNodeValue ) || null;
			}
		}

		return null;
	},

	/**
	 * Gets a list node from the XML document, based on a XPath query.
	 * @param {String} xpath The XPath query to execute.
	 * @param {Object} [contextNode] The XML DOM node to be used as the context
	 *		for the XPath query. The document root is used by default.
	 * @returns {ArrayLike} An array containing all matched nodes. The array will
	 *		be empty if the query has no results.
	 * @example
	 * // Create the XML instance.
	 * var xml = new CKEDITOR.xml( '<list><item id="test1" /><item id="test2" /></list>' );
	 * // Get the first <item> node.
	 * var itemNodes = xml.selectSingleNode( 'list/item' );
	 * // Alert "item" twice, one for each <item>.
	 * for ( var i = 0 ; i < itemNodes.length ; i++ )
	 *     alert( itemNodes[i].nodeName );
	 */
	selectNodes : function( xpath, contextNode )
	{
		var baseXml = this.baseXml,
			nodes = [];

		if ( contextNode || ( contextNode = baseXml ) )
		{
			if ( CKEDITOR.env.ie || contextNode.selectNodes )		// IE
				return contextNode.selectNodes( xpath );
			else if ( baseXml.evaluate )							// Others
			{
				var result = baseXml.evaluate( xpath, contextNode, null, 5, null);

				if ( result )
				{
					var node;
					while( ( node = result.iterateNext() ) )
						nodes.push( node );
				}
			}
		}

		return nodes;
	},

	/**
	 * Gets the string representation of hte inner contents of a XML node,
	 * based on a XPath query.
	 * @param {String} xpath The XPath query to execute.
	 * @param {Object} [contextNode] The XML DOM node to be used as the context
	 *		for the XPath query. The document root is used by default.
	 * @returns {String} The textual representation of the inner contents of
	 *		the node or null if the query has no results.
	 * @example
	 * // Create the XML instance.
	 * var xml = new CKEDITOR.xml( '<list><item id="test1" /><item id="test2" /></list>' );
	 * // Alert "<item id="test1" /><item id="test2" />".
	 * alert( xml.getInnerXml( 'list' ) );
	 */
	getInnerXml : function( xpath, contextNode )
	{
		var node = this.selectSingleNode( xpath, contextNode ),
			xml = [];
		if ( node )
		{
			node = node.firstChild;
			while ( node )
			{
				if ( node.xml )				// IE
					xml.push( node.xml );
				else if ( window.XMLSerializer )	// Others
					xml.push( ( new XMLSerializer() ).serializeToString( node ) );

				node = node.nextSibling;
			}
		}

		return xml.length ? xml.join( '' ) : null;
	}
};
