/*
 * xslt.js
 *
 * Copyright (c) 2005-2008 Johann Burkard (<mailto:jb@eaio.com>)
 * <http://eaio.com>
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
 * NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 * 
 */

/**
 * Constructor for client-side XSLT transformations.
 * 
 * @author <a href="mailto:jb@eaio.com">Johann Burkard</a>
 * @version $Id: xslt.js,v 1.7 2008/08/29 21:22:55 Johann Exp $
 * @constructor
 */
function Transformation() {

    var xml;
    
    var xmlDoc;
    
    var xslt;
    
    var xsltDoc;

    var callback = function() {};
    
    /**
     * Sort of like a fix for Opera who doesn't always get readyStates right.
     */
    var transformed = false;
        
    /**
     * Returns the URL of the XML document.
     * 
     * @return the URL of the XML document
     * @type String
     */
    this.getXml = function() {
        return xml;
    }
    
    /**
     * Returns the XML document.
     * 
     * @return the XML document
     */
    this.getXmlDocument = function() {
        return xmlDoc
    }
    
    /**
     * Sets the URL of the XML document.
     * 
     * @param x the URL of the XML document
     * @return this
     * @type Transformation
     */
    this.setXml = function(x) {
        xml = x;
        return this;
    }
    
    /**
     * Returns the URL of the XSLT document.
     * 
     * @return the URL of the XSLT document
     * @type String
     */
    this.getXslt = function() {
        return xslt;
    }
    
    /**
     * Returns the XSLT document.
     * 
     * @return the XSLT document
     */
    this.getXsltDocument = function() {
        return xsltDoc;
    }
    
    /**
     * Sets the URL of the XSLT document.
     * 
     * @param x the URL of the XML document
     * @return this
     * @type Transformation
     */
    this.setXslt = function(x) {
        xslt = x;
        return this;
    }
    
    /**
     * Returns the callback function.
     * 
     * @return the callback function
     */
    this.getCallback = function() {
        return callback;
    }
    
    /**
     * Sets the callback function
     * 
     * @param c the callback function
     * @return this
     * @type Transformation
     */
    this.setCallback = function(c) {
        callback = c;
        return this;
    }
    
    /**
     * Sets the target element to write the transformed content to and <em>asynchronously</em>
     * starts the transformation process.
     * <p>
     * <code>target</code> is the ID of an element. 2DO
     * <p>
     * This method may only be called after {@link #setXml} and {@link #setXslt} have
     * been called.
     * <p>
     * Note that the target element must exist once this method is called. Calling
     * this method before <code>onload</code> was fired will most likely
     * not work.
     * 
     * @param target the ID of an element
     */
    this.transform = function(target) {
        if (!browserSupportsXSLT()) {
           return;
        }
        var str = /^\s*</;
        var t = this;
        if (document.recalc) {
            var change = function() {
                var c = 'complete';
                if (xm.readyState == c && xs.readyState == c) {
                    window.setTimeout(function() {
                        xmlDoc = xm.XMLDocument;
                        xsltDoc = xs.XMLDocument;
                        callback(t);
                        document.all[target].innerHTML = xm.transformNode(xs.XMLDocument);
                    }, 50);
                }
            };
            
            var xm = document.createElement('xml');
            xm.onreadystatechange = change;
            xm[str.test(xml) ? "innerHTML" : "src"] = xml;
            
            var xs = document.createElement('xml');
            xs.onreadystatechange = change;
            xs[str.test(xslt) ? "innerHTML" : "src"] = xslt;
            
            with (document.body) {
                insertBefore(xm);
                insertBefore(xs);
            };
        }
        else {
            var transformed = false;

            var xm = {
                readyState: 4
            };
            var xs = {
                readyState: 4
            };
            var change = function() {
                if (xm.readyState == 4 && xs.readyState == 4 && !transformed) {
                    xmlDoc = xm.responseXML;
                    xsltDoc = xs.responseXML;
                    var resultDoc;
                    var processor = new XSLTProcessor();
                                       
                    if (typeof processor.transformDocument == 'function') {
                        // obsolete Mozilla interface
                        resultDoc = document.implementation.createDocument("", "", null);
                        processor.transformDocument(xm.responseXML, xs.responseXML, resultDoc, null);
                        var out = new XMLSerializer().serializeToString(resultDoc);
                        callback(t);
                        document.getElementById(target).innerHTML = out;
                    }
                    else {
                        processor.importStylesheet(xs.responseXML);
                        resultDoc = processor.transformToFragment(xm.responseXML, document);
                        callback(t);
                        document.getElementById(target).innerHTML = '';
                        document.getElementById(target).appendChild(resultDoc);
                    }
                    
                    transformed = true;
                }
            };

            if (str.test(xml)) {
                xm.responseXML = new DOMParser().parseFromString(xml, "text/xml");
            }
            else {
                xm = new XMLHttpRequest();
                xm.onreadystatechange = change;
                xm.open("GET", xml);
                xm.send(null);
            }

            if (str.test(xslt)) {
                xs.responseXML = new DOMParser().parseFromString(xslt, "text/xml");
                change();
            }
            else {
                xs = new XMLHttpRequest();
                xs.onreadystatechange = change;
                xs.open("GET", xslt);
                xs.send(null);
            }
        }
    }

}

/**
 * Returns whether the browser supports XSLT.
 * 
 * @return the browser supports XSLT
 * @type boolean
 */
function browserSupportsXSLT() {
    var support = false;
    if (document.recalc) { // IE 5+
        support = true;
    }
    else if (window.XMLHttpRequest != undefined && window.XSLTProcessor != undefined) { // Mozilla 0.9.4+, Opera 9+
       var processor = new XSLTProcessor();
       if (typeof processor.transformDocument == 'function') {
           support = window.XMLSerializer != undefined;
       }
       else {
           support = true;
       }
    }
    return support;
}