/************************************************************************
**
**  Copyright (C) 2012 Dave Heiland
**  Copyright (C) 2012 John Schember <john@nachtimwald.com>
**
**  This file is part of Sigil.
**
**  Sigil 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, either version 3 of the License, or
**  (at your option) any later version.
**
**  Sigil 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 Sigil.  If not, see <http://www.gnu.org/licenses/>.
**
*************************************************************************/

#include <boost/bind/bind.hpp>

#include <QtCore/QtCore>
#include <QtCore/QString>
#include <QtConcurrent/QtConcurrent>

#include "BookManipulation/XercesCppUse.h"
#include "BookManipulation/XhtmlDoc.h"
#include "ResourceObjects/HTMLResource.h"
#include "Misc/Utility.h"
#include "sigil_constants.h"
#include "SourceUpdates/LinkUpdates.h"

using boost::shared_ptr;

static QString HTML_XML_NAMESPACE = "http://www.w3.org/1999/xhtml";


void LinkUpdates::UpdateLinksInAllFiles(const QList<HTMLResource *> &html_resources, const QList<QString> new_stylesheets)
{
    QtConcurrent::blockingMap(html_resources, boost::bind(UpdateLinksInOneFile, _1, new_stylesheets));
}

void LinkUpdates::UpdateLinksInOneFile(HTMLResource *html_resource, QList<QString> new_stylesheets)
{
    Q_ASSERT(html_resource);
    QWriteLocker locker(&html_resource->GetLock());
    shared_ptr<xc::DOMDocument> d = XhtmlDoc::LoadTextIntoDocument(html_resource->GetText());
    xc::DOMDocument &document = *d.get();
    // head should only appear once
    xc::DOMNodeList *heads = document.getElementsByTagName(QtoX("head"));
    xc::DOMElement &head_element = *static_cast<xc::DOMElement *>(heads->item(0));
    // We only want links in the head
    xc::DOMNodeList *links = head_element.getElementsByTagName(QtoX("link"));
    // Remove the old stylesheet links
    // Link count is dynamic
    uint links_count = links->getLength();

    for (uint i = 0; i < links_count; i++) {
        // Always delete the top element since list is dynamic
        xc::DOMElement &element = *static_cast<xc::DOMElement *>(links->item(0));
        Q_ASSERT(&element);

        if (element.hasAttribute(QtoX("type")) &&
            XtoQ(element.getAttribute(QtoX("type"))) == "text/css" &&
            element.hasAttribute(QtoX("rel")) &&
            XtoQ(element.getAttribute(QtoX("rel"))) == "stylesheet") {
            head_element.removeChild(&element);
        }
    }

    // Add the new stylesheet links
    foreach(QString stylesheet, new_stylesheets) {
        xc::DOMElement *element = document.createElementNS(QtoX(HTML_XML_NAMESPACE), QtoX("link"));
        element->setAttribute(QtoX("href"), QtoX(stylesheet));
        element->setAttribute(QtoX("type"), QtoX("text/css"));
        element->setAttribute(QtoX("rel"),  QtoX("stylesheet"));
        head_element.appendChild(element);
    }
    html_resource->SetText(XhtmlDoc::GetDomDocumentAsString(document));
}
