/*

 * This file is part of the API Extractor project.

 *

 * Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

 *

 * Contact: PySide team <contact@pyside.org>

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * version 2 as published by the Free Software Foundation.

 *

 * 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 St, Fifth Floor, Boston, MA

 * 02110-1301 USA

 *

 */

#include "docparser.h"

#include <QtCore/QDebug>

#include <QtXmlPatterns/QXmlQuery>

#include <QBuffer>

#include <cstdlib>

#include <libxslt/xsltutils.h>

#include <libxslt/transform.h>

DocParser::DocParser()

{

    xmlSubstituteEntitiesDefault(1);

}

DocParser::~DocParser()

{

}

QString DocParser::getDocumentation(QXmlQuery& xquery, const QString& query,

                                    const DocModificationList& mods) const

{

    QString doc = execXQuery(xquery, query);

    return applyDocModifications(mods, doc);

}

QString DocParser::execXQuery(QXmlQuery& xquery, const QString& query) const

{

    QString escapedQuery(query);

    // XQuery can't have invalid XML characters

    escapedQuery.replace("&", "&amp;").replace("<", "&lt;");

    xquery.setQuery(escapedQuery);

    if (!xquery.isValid()) {

        qWarning() << "Bad XQuery: " << escapedQuery;

        return QString();

    }

    QString result;

    xquery.evaluateTo(&result);

    return result;

}

namespace

{

struct XslResources

{

    xmlDocPtr xmlDoc;

    xsltStylesheetPtr xslt;

    xmlDocPtr xslResult;

    XslResources() : xmlDoc(0), xslt(0), xslResult(0) {}

    ~XslResources()

    {

        if (xslt)

            xsltFreeStylesheet(xslt);

        if (xslResult)

            xmlFreeDoc(xslResult);

        if (xmlDoc)

            xmlFreeDoc(xmlDoc);

        xsltCleanupGlobals();

        xmlCleanupParser();

    }

};

} // namespace

QString DocParser::applyDocModifications(const DocModificationList& mods, const QString& xml) const

{

    if (mods.isEmpty())

        return xml;

    bool hasXPathBasedModification = false;

    foreach (DocModification mod, mods) {

        if (mod.mode() == DocModification::XPathReplace) {

            hasXPathBasedModification = true;

            break;

        }

    }

    if (!hasXPathBasedModification)

        return xml;

    QString xsl = QLatin1String("<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n"

                                "<xsl:transform version=\"1.0\" xmlns:xsl=\"http://www.w3.org/1999/XSL/Transform\">\n"

                                "<xsl:template match=\"/\">\n"

                                "    <xsl:apply-templates />\n"

                                "</xsl:template>\n"

                                "<xsl:template match=\"*\">\n"

                                "<xsl:copy>\n"

                                "    <xsl:copy-of select=\"@*\"/>\n"

                                "    <xsl:apply-templates/>\n"

                                "</xsl:copy>\n"

                                "</xsl:template>\n"

                               );

    foreach (DocModification mod, mods) {

        if (mod.mode() == DocModification::XPathReplace) {

            xsl += QLatin1String("<xsl:template match=\"")

                   + mod.xpath().replace("\"", """) + QLatin1String("\">")

                   + mod.code() + QLatin1String("</xsl:template>\n");

        }

    }

    xsl += QLatin1String("</xsl:transform>");

    XslResources res;

    // Read XML data

    QByteArray xmlData = xml.toUtf8();

    res.xmlDoc = xmlParseMemory(xmlData.constData(), xmlData.size());

    if (!res.xmlDoc)

        return xml;

    // Read XSL data as a XML file

    QByteArray xslData = xsl.toUtf8();

    // xsltFreeStylesheet will delete this pointer

    xmlDocPtr xslDoc = xmlParseMemory(xslData.constData(), xslData.size());

    if (!xslDoc)

        return xml;

    // Parse XSL data

    res.xslt = xsltParseStylesheetDoc(xslDoc);

    if (!res.xslt)

        return xml;

    // Apply XSL

    res.xslResult = xsltApplyStylesheet(res.xslt, res.xmlDoc, 0);

    xmlChar* buffer = 0;

    int bufferSize;

    QString result;

    if (!xsltSaveResultToString(&buffer, &bufferSize, res.xslResult, res.xslt)) {

        result = QString::fromUtf8(reinterpret_cast<char*>(buffer), bufferSize);

        std::free(buffer);

    } else {

        result = xml;

    }

    Q_ASSERT(result != xml);

    return result;

}