/*
    SPDX-FileCopyrightText: 2005 Piotr Szymański <niedakh@gmail.com>
    SPDX-FileCopyrightText: 2008 Albert Astals Cid <aacid@kde.org>

    SPDX-License-Identifier: GPL-2.0-or-later
*/

#include "generator_chm.h"

#include <QDomElement>
#include <QEventLoop>
#include <QMutex>
#include <QPainter>

#include <KAboutData>
#include <KHTMLView>
#include <KLocalizedString>
#include <QUrl>
#include <dom/dom_html.h>
#include <dom/dom_node.h>
#include <dom/html_misc.h>
#include <khtml_part.h>

#include <core/action.h>
#include <core/page.h>
#include <core/textpage.h>
#include <core/utils.h>

OKULAR_EXPORT_PLUGIN(CHMGenerator, "libokularGenerator_chmlib.json")

static QString absolutePath(const QString &baseUrl, const QString &path)
{
    QString absPath;
    if (path.startsWith(QLatin1Char('/'))) {
        // already absolute
        absPath = path;
    } else {
        QUrl url = QUrl::fromLocalFile(baseUrl).adjusted(QUrl::RemoveFilename);
        url.setPath(url.path() + path);
        absPath = url.toLocalFile();
    }
    return absPath;
}

CHMGenerator::CHMGenerator(QObject *parent, const QVariantList &args)
    : Okular::Generator(parent, args)
{
    setFeature(TextExtraction);

    m_syncGen = nullptr;
    m_file = nullptr;
    m_request = nullptr;
}

CHMGenerator::~CHMGenerator()
{
    delete m_syncGen;
}

bool CHMGenerator::loadDocument(const QString &fileName, QVector<Okular::Page *> &pagesVector)
{
    m_file = EBook::loadFile(fileName);
    if (!m_file) {
        return false;
    }
    m_fileName = fileName;
    QList<EBookTocEntry> topics;
    m_file->getTableOfContents(topics);

    // fill m_docSyn
    QMap<int, QDomElement> lastIndentElement;
    QMap<QString, int> tmpPageList;
    int pageNum = 0;

    for (const EBookTocEntry &e : qAsConst(topics)) {
        QDomElement item = m_docSyn.createElement(e.name);
        if (!e.url.isEmpty()) {
            QString url = e.url.toString();
            item.setAttribute(QStringLiteral("ViewportName"), url);
            if (!tmpPageList.contains(url)) { // add a page only once
                tmpPageList.insert(url, pageNum);
                pageNum++;
            }
        }
        item.setAttribute(QStringLiteral("Icon"), e.iconid);
        if (e.indent == 0) {
            m_docSyn.appendChild(item);
        } else {
            lastIndentElement[e.indent - 1].appendChild(item);
        }
        lastIndentElement[e.indent] = item;
    }

    // fill m_urlPage and m_pageUrl
    QList<QUrl> pageList;
    m_file->enumerateFiles(pageList);
    const QUrl home = m_file->homeUrl();
    if (home.path() != QLatin1String("/")) {
        pageList.prepend(home);
    }
    m_pageUrl.resize(pageNum);

    for (const QUrl &qurl : qAsConst(pageList)) {
        QString url = qurl.toString();
        const QString urlLower = url.toLower();
        if (!urlLower.endsWith(QLatin1String(".html")) && !urlLower.endsWith(QLatin1String(".htm"))) {
            continue;
        }

        int pos = url.indexOf(QLatin1Char(('#')));
        // insert the url into the maps, but insert always the variant without the #ref part
        QString tmpUrl = pos == -1 ? url : url.left(pos);

        // url already there, abort insertion
        if (m_urlPage.contains(tmpUrl)) {
            continue;
        }

        int foundPage = tmpPageList.value(tmpUrl, -1);
        if (foundPage != -1) {
            m_urlPage.insert(tmpUrl, foundPage);
            m_pageUrl[foundPage] = tmpUrl;
        } else {
            // add pages not present in toc
            m_urlPage.insert(tmpUrl, pageNum);
            m_pageUrl.append(tmpUrl);
            pageNum++;
        }
    }

    pagesVector.resize(m_pageUrl.count());
    m_textpageAddedList.fill(false, pagesVector.count());
    m_rectsGenerated.fill(false, pagesVector.count());

    if (!m_syncGen) {
        m_syncGen = new KHTMLPart();
    }
    disconnect(m_syncGen, nullptr, this, nullptr);

    for (int i = 0; i < m_pageUrl.count(); ++i) {
        preparePageForSyncOperation(m_pageUrl.at(i));
        pagesVector[i] = new Okular::Page(i, m_syncGen->view()->contentsWidth(), m_syncGen->view()->contentsHeight(), Okular::Rotation0);
    }

    connect(m_syncGen, QOverload<>::of(&KHTMLPart::completed), this, &CHMGenerator::slotCompleted);
    connect(m_syncGen, &KParts::ReadOnlyPart::canceled, this, &CHMGenerator::slotCompleted);

    return true;
}

bool CHMGenerator::doCloseDocument()
{
    // delete the document information of the old document
    delete m_file;
    m_file = nullptr;
    m_textpageAddedList.clear();
    m_rectsGenerated.clear();
    m_urlPage.clear();
    m_pageUrl.clear();
    m_docSyn.clear();
    if (m_syncGen) {
        m_syncGen->closeUrl();
    }

    return true;
}

void CHMGenerator::preparePageForSyncOperation(const QString &url)
{
    QString pAddress = QStringLiteral("ms-its:") + m_fileName + QStringLiteral("::") + m_file->urlToPath(QUrl(url));
    m_chmUrl = url;

    m_syncGen->openUrl(QUrl(pAddress));
    m_syncGen->view()->layout();

    QEventLoop loop;
    connect(m_syncGen, QOverload<>::of(&KHTMLPart::completed), &loop, &QEventLoop::quit);
    connect(m_syncGen, &KParts::ReadOnlyPart::canceled, &loop, &QEventLoop::quit);
    // discard any user input, otherwise it breaks the "synchronicity" of this
    // function
    loop.exec(QEventLoop::ExcludeUserInputEvents);
}

void CHMGenerator::slotCompleted()
{
    if (!m_request) {
        return;
    }

    QImage image(m_request->width(), m_request->height(), QImage::Format_ARGB32);
    image.fill(Qt::white);

    QPainter p(&image);
    QRect r(0, 0, m_request->width(), m_request->height());

    bool moreToPaint;
    m_syncGen->paint(&p, r, 0, &moreToPaint);

    p.end();

    if (!m_textpageAddedList.at(m_request->pageNumber())) {
        additionalRequestData();
        m_textpageAddedList[m_request->pageNumber()] = true;
    }

    m_syncGen->closeUrl();
    m_chmUrl = QString();

    userMutex()->unlock();

    Okular::PixmapRequest *req = m_request;
    m_request = nullptr;

    if (!req->page()->isBoundingBoxKnown()) {
        updatePageBoundingBox(req->page()->number(), Okular::Utils::imageBoundingBox(&image));
    }
    req->page()->setPixmap(req->observer(), new QPixmap(QPixmap::fromImage(image)));
    signalPixmapRequestDone(req);
}

Okular::DocumentInfo CHMGenerator::generateDocumentInfo(const QSet<Okular::DocumentInfo::Key> &keys) const
{
    Okular::DocumentInfo docInfo;
    if (keys.contains(Okular::DocumentInfo::MimeType)) {
        docInfo.set(Okular::DocumentInfo::MimeType, QStringLiteral("application/x-chm"));
    }
    if (keys.contains(Okular::DocumentInfo::Title)) {
        docInfo.set(Okular::DocumentInfo::Title, m_file->title());
    }
    return docInfo;
}

const Okular::DocumentSynopsis *CHMGenerator::generateDocumentSynopsis()
{
    return &m_docSyn;
}

bool CHMGenerator::canGeneratePixmap() const
{
    bool isLocked = true;
    if (userMutex()->tryLock()) {
        userMutex()->unlock();
        isLocked = false;
    }

    return !isLocked;
}

void CHMGenerator::generatePixmap(Okular::PixmapRequest *request)
{
    int requestWidth = request->width();
    int requestHeight = request->height();

    userMutex()->lock();
    QString url = m_pageUrl[request->pageNumber()];

    QString pAddress = QStringLiteral("ms-its:") + m_fileName + QStringLiteral("::") + m_file->urlToPath(QUrl(url));
    m_chmUrl = url;
    m_syncGen->view()->resizeContents(requestWidth, requestHeight);
    m_request = request;
    // will Q_EMIT openURL without problems
    m_syncGen->openUrl(QUrl(pAddress));
}

void CHMGenerator::recursiveExploreNodes(DOM::Node node, Okular::TextPage *tp)
{
    if (node.nodeType() == DOM::Node::TEXT_NODE && !node.getRect().isNull()) {
        QString nodeText = node.nodeValue().string();
        QRect r = node.getRect();
        int vWidth = m_syncGen->view()->width();
        int vHeight = m_syncGen->view()->height();
        Okular::NormalizedRect *nodeNormRect;
#define NOEXP
#ifndef NOEXP
        int x, y, height;
        int x_next, y_next, height_next;
        int nodeTextLength = nodeText.length();
        if (nodeTextLength == 1) {
            nodeNormRect = new Okular::NormalizedRect(r, vWidth, vHeight);
            tp->append(nodeText, nodeNormRect, nodeNormRect->bottom, 0, (nodeText == "\n"));
        } else {
            for (int i = 0; i < nodeTextLength; i++) {
                node.getCursor(i, x, y, height);
                if (i == 0)
                // i is 0, use left rect boundary
                {
                    //                     if (nodeType[i+1]
                    node.getCursor(i + 1, x_next, y_next, height_next);
                    nodeNormRect = new Okular::NormalizedRect(QRect(x, y, x_next - x - 1, height), vWidth, vHeight);
                } else if (i < nodeTextLength - 1)
                // i is between zero and the last element
                {
                    node.getCursor(i + 1, x_next, y_next, height_next);
                    nodeNormRect = new Okular::NormalizedRect(QRect(x, y, x_next - x - 1, height), vWidth, vHeight);
                } else
                // the last element use right rect boundary
                {
                    node.getCursor(i - 1, x_next, y_next, height_next);
                }
            }
#else
        nodeNormRect = new Okular::NormalizedRect(r, vWidth, vHeight);
        tp->append(nodeText, nodeNormRect /*,0*/);
#endif
        }
        DOM::Node child = node.firstChild();
        while (!child.isNull()) {
            recursiveExploreNodes(child, tp);
            child = child.nextSibling();
        }
    }

    void CHMGenerator::additionalRequestData()
    {
        Okular::Page *page = m_request->page();
        const bool genObjectRects = !m_rectsGenerated.at(m_request->page()->number());
        const bool genTextPage = !m_request->page()->hasTextPage() && genObjectRects;

        if (genObjectRects || genTextPage) {
            DOM::HTMLDocument domDoc = m_syncGen->htmlDocument();
            // only generate object info when generating a full page not a thumbnail
            if (genObjectRects) {
                QList<Okular::ObjectRect *> objRects;
                int xScale = m_syncGen->view()->width();
                int yScale = m_syncGen->view()->height();
                // getting links
                DOM::HTMLCollection coll = domDoc.links();
                DOM::Node n;
                QRect r;
                if (!coll.isNull()) {
                    int size = coll.length();
                    for (int i = 0; i < size; i++) {
                        n = coll.item(i);
                        if (!n.isNull()) {
                            QString url = n.attributes().getNamedItem("href").nodeValue().string();
                            r = n.getRect();
                            // there is no way for us to support javascript properly
                            if (url.startsWith(QLatin1String("JavaScript:")), Qt::CaseInsensitive) {
                                continue;
                            } else if (url.contains(QStringLiteral(":"))) {
                                objRects.push_back(new Okular::ObjectRect(Okular::NormalizedRect(r, xScale, yScale), false, Okular::ObjectRect::Action, new Okular::BrowseAction(QUrl(url))));
                            } else {
                                Okular::DocumentViewport viewport(metaData(QStringLiteral("NamedViewport"), absolutePath(m_chmUrl, url)).toString());
                                objRects.push_back(new Okular::ObjectRect(Okular::NormalizedRect(r, xScale, yScale), false, Okular::ObjectRect::Action, new Okular::GotoAction(QString(), viewport)));
                            }
                        }
                    }
                }

                // getting images
                coll = domDoc.images();
                if (!coll.isNull()) {
                    int size = coll.length();
                    for (int i = 0; i < size; i++) {
                        n = coll.item(i);
                        if (!n.isNull()) {
                            objRects.push_back(new Okular::ObjectRect(Okular::NormalizedRect(n.getRect(), xScale, yScale), false, Okular::ObjectRect::Image, nullptr));
                        }
                    }
                }
                m_request->page()->setObjectRects(objRects);
                m_rectsGenerated[m_request->page()->number()] = true;
            }

            if (genTextPage) {
                Okular::TextPage *tp = new Okular::TextPage();
                recursiveExploreNodes(domDoc, tp);
                page->setTextPage(tp);
            }
        }
    }

    Okular::TextPage *CHMGenerator::textPage(Okular::TextRequest * request)
    {
        userMutex()->lock();

        const Okular::Page *page = request->page();
        m_syncGen->view()->resize(page->width(), page->height());

        preparePageForSyncOperation(m_pageUrl[page->number()]);
        Okular::TextPage *tp = new Okular::TextPage();
        recursiveExploreNodes(m_syncGen->htmlDocument(), tp);
        userMutex()->unlock();
        return tp;
    }

    QVariant CHMGenerator::metaData(const QString &key, const QVariant &option) const
    {
        if (key == QLatin1String("NamedViewport") && !option.toString().isEmpty()) {
            const int pos = option.toString().indexOf(QLatin1Char('#'));
            QString tmpUrl = pos == -1 ? option.toString() : option.toString().left(pos);
            Okular::DocumentViewport viewport;
            QMap<QString, int>::const_iterator it = m_urlPage.find(tmpUrl);
            if (it != m_urlPage.end()) {
                viewport.pageNumber = it.value();
                return viewport.toString();
            }

        } else if (key == QLatin1String("DocumentTitle")) {
            return m_file->title();
        }
        return QVariant();
    }

    /* kate: replace-tabs on; tab-width 4; */

#include "generator_chm.moc"