<?php
/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; under version 2
 * of the License (non-upgradable).
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Copyright (c) 2002-2008 (original work) Public Research Centre Henri Tudor & University of Luxembourg (under the project TAO & TAO2);
 *               2008-2010 (update and modification) Deutsche Institut für Internationale Pädagogische Forschung (under the project TAO-TRANSFER);
 *               2009-2012 (update and modification) Public Research Centre Henri Tudor (under the project TAO-SUSTAIN & TAO-DEV);
 *
 */

/**
 * Helper for automatisation of Xsl transformation
 * @access public
 * @author Matteo Melis
 * @package taoItems

 */
class taoItems_helpers_Xslt
{
    // namespace for the set parameters function
    const PARAMS_NS = '';
    // xlst namespace short and full
    const XSLT_NS = 'http://www.w3.org/1999/XSL/Transform';
    const XSLT_SHORT_NS = 'xsl';

    /**
     *  Transform the given xml with the given stylesheet adding params if necessary
     *
     * @param string $xml the xml raw or filepath
     * @param string $xsl the xsl raw or filepath
     * @param array $params  key = name of param and value = value of param
     * @return string the result of transformation
     */
    public static function quickTransform($xml, $xsl, $params = [])
    {
        // load xml
        $xml_dom = self::getDOM($xml);
        // get the xsl preparated
        $xsl_dom = self::prepareXsl($xsl, $params);
        // return the transformation
        return self::transform($xml_dom, $xsl_dom, $params);
    }

    /**
     * return the xslt processor with the xsl stylesheet loaded
     * @param DOMDocument $xsl
     * @return XSLTProcessor
     */
    public static function getProcessor($xsl_dom)
    {
        // get the processor and import stylesheet xsl
        $xsl_processor = new XSLTProcessor();
        $xsl_processor->importStylesheet($xsl_dom);
        return $xsl_processor;
    }

    /**
     * prepare the xsl stylesheet and add params dynamically
     * @param string $xsl
     * @param array $params
     * @return DOMDocument
     */
    public static function prepareXsl($xsl, $params = [])
    {
        // load xsl
        $xsl_dom = self::getDOM($xsl);
        // a way to use param xsl dynamically
        return self::addParams($xsl_dom, $params); // voir avec lionel si peut rester la
    }

    /**
     *
     * @param mixed $xml (string or DOMDocument
     * @param XSLTProcessor $xsl_proc
     * @param array $params
     * @return string the result of transformation
     */
    public static function transform($xml, $xsl, $params = [])
    {
        // if xml is string tranform to DOM
        if (is_string($xml)) {
            $xml = self::getDOM($xml);
        }
        // if xsl is string tranform to DOM
        if (is_string($xsl)) {
            $xsl = self::getDOM($xsl);
        }
        //get the processor with the stylesheet
        $xsl_proc = self::getProcessor($xsl);
        // set values for params
        if (sizeof($params)) {
            $xsl_proc->setParameter(self::PARAMS_NS, $params);
        }
        // transformation
        return $xsl_proc->transformToXML($xml);
    }

    /**
     * return the DOM corresponding to the parameter
     * @param string $str
     * @return DOMDocument
     */
    public static function getDOM($str)
    {
        //create domdocument
        $dom = new DOMDocument();
        //load by file or string
        is_file($str) ? $dom->load($str) : $dom->loadXML($str);
        // return the DOMDoc
        return $dom;
    }

    /**
     * insert the tag param for each params noexistent in xsl stylesheet
     * @param DOMPDocument $dom
     * @return DOMDocument
     */
    private static function addParams($dom, $params)
    {
        if (!sizeof($params)) {
            return $dom;
        }
        // get xpath
        $xpath = new DOMXPath($dom);
        //registering namespace xsl
        $xpath->registerNamespace(self::XSLT_SHORT_NS, self::XSLT_NS);
        // get the params tag direct child of the stylesheet (don't touch other params as template for example)
        $items = $xpath->query('/' . self::XSLT_SHORT_NS . ':stylesheet|' . self::XSLT_SHORT_NS . ':transform/' . self::XSLT_SHORT_NS . ':param');
        // list existing to don't duplicate it
        $existing = [];
        foreach ($items as $param) {
            $existing[] = $param->getAttribute('name');
        }
        // for each item in param
        foreach ($params as $name => $val) {
            // if not exist in dom
            if (!in_array($name, $existing)) {
                // we add it to the dom
                $node = $dom->createElementNS(self::XSLT_NS, self::XSLT_SHORT_NS . ":param");
                $node->setAttribute('name', $name);
                // log to say param added dynamically
                common_Logger::w('Parameters "' . $name . '"added automatically by the ' . get_class() . ':addParams \'s function because it was missing in the xsl stylesheet');
            }
        }
        return $dom;
    }
}