/*
    SPDX-FileCopyrightText: 2002 Frerich Raabe <raabe@kde.org>

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

#include "toc.h"

#include "docentry.h"
#include "khc_debug.h"

#include <QApplication>
#include <QFileInfo>
#include <QIcon>
#include <QStandardPaths>
#include <QTextStream>

#include <KProcess>
#include <KXmlGuiWindow>
#include <docbookxslt.h>

#include <sys/stat.h>

using namespace KHC;

class TOCItem : public NavigatorItem
{
public:
    TOCItem(TOC *parent, QTreeWidgetItem *parentItem, QTreeWidgetItem *after, const QString &text);

    const TOC *toc() const
    {
        return m_toc;
    }

private:
    TOC *m_toc = nullptr;
};

class TOCChapterItem : public TOCItem
{
public:
    TOCChapterItem(TOC *toc, NavigatorItem *parent, QTreeWidgetItem *after, const QString &title, const QString &name);

    virtual QString url();

private:
    QString m_name;
};

class TOCSectionItem : public TOCItem
{
public:
    TOCSectionItem(TOC *toc, TOCChapterItem *parent, QTreeWidgetItem *after, const QString &title, const QString &name);

    virtual QString url();

private:
    QString m_name;
};

bool TOC::m_alreadyWarned = false;

TOC::TOC(NavigatorItem *parentItem)
    : m_parentItem(parentItem)
{
}

void TOC::build(const QString &file)
{
    QFileInfo fileInfo(file);
    QString fileName = fileInfo.absoluteFilePath();
    const QStringList resourceDirs = KDocTools::documentationDirs();
    QStringList::ConstIterator it = resourceDirs.begin();
    QStringList::ConstIterator end = resourceDirs.end();
    for (; it != end; ++it) {
        if (fileName.startsWith(*it)) {
            fileName.remove(0, (*it).length());
            break;
        }
    }

    QString cacheFile = fileName.replace(QLatin1Char('/'), QStringLiteral("__"));
#ifdef Q_WS_WIN
    cacheFile.replace(QLatin1Char(':'), QStringLiteral("_"));
#endif
    m_cacheFile = QStandardPaths::writableLocation(QStandardPaths::CacheLocation) + QStringLiteral("/help/") + cacheFile;
    m_sourceFile = file;

    if (cacheStatus() == NeedRebuild)
        buildCache();
    else
        fillTree();
}

TOC::CacheStatus TOC::cacheStatus() const
{
    if (!QFile::exists(m_cacheFile) || sourceFileCTime() != cachedCTime())
        return NeedRebuild;

    return CacheOk;
}

int TOC::sourceFileCTime() const
{
    struct stat stat_buf;
    stat(QFile::encodeName(m_sourceFile).data(), &stat_buf);

    return stat_buf.st_ctime;
}

int TOC::cachedCTime() const
{
    QFile f(m_cacheFile);
    if (!f.open(QIODevice::ReadOnly))
        return 0;

    QDomDocument doc;
    if (!doc.setContent(&f))
        return 0;

    QDomComment timestamp = doc.documentElement().lastChild().toComment();

    return timestamp.data().trimmed().toInt();
}

void TOC::buildCache()
{
    KXmlGuiWindow *mainWindow = dynamic_cast<KXmlGuiWindow *>(qobject_cast<QApplication *>(qApp)->activeWindow());

    KProcess *meinproc = new KProcess;
    connect(meinproc, QOverload<int, QProcess::ExitStatus>::of(&KProcess::finished), this, &TOC::meinprocExited);

    *meinproc << QStandardPaths::findExecutable(QStringLiteral("meinproc6"));
    *meinproc << QStringLiteral("--stylesheet")
              << QStandardPaths::locate(QStandardPaths::GenericDataLocation, QStringLiteral("khelpcenter/table-of-contents.xslt"));
    *meinproc << QStringLiteral("--output") << m_cacheFile;
    *meinproc << m_sourceFile;

    meinproc->setOutputChannelMode(KProcess::OnlyStderrChannel);
    meinproc->start();
    if (!meinproc->waitForStarted()) {
        qCWarning(KHC_LOG) << "could not start process" << meinproc->program();
        if (mainWindow && !m_alreadyWarned) {
            ; // add warning message box with don't display again option
            m_alreadyWarned = true;
        }
        delete meinproc;
    }
}

void TOC::meinprocExited(int exitCode, QProcess::ExitStatus exitStatus)
{
    KProcess *meinproc = static_cast<KProcess *>(sender());
    KXmlGuiWindow *mainWindow = dynamic_cast<KXmlGuiWindow *>(qobject_cast<QApplication *>(qApp)->activeWindow());

    if (exitStatus == QProcess::CrashExit || exitCode != 0) {
        qCWarning(KHC_LOG) << "running" << meinproc->program() << "failed with exitCode" << exitCode;
        qCWarning(KHC_LOG) << "stderr output:" << meinproc->readAllStandardError();
        if (mainWindow && !m_alreadyWarned) {
            ; // add warning message box with don't display again option
            m_alreadyWarned = true;
        }
        delete meinproc;
        return;
    }

    delete meinproc;

    // add a timestamp to the meinproc4 created xml file
    QFile f(m_cacheFile);
    if (!f.open(QIODevice::ReadWrite))
        return;

    QDomDocument doc;
    if (!doc.setContent(&f))
        return;

    QDomComment timestamp = doc.createComment(QString::number(sourceFileCTime()));
    doc.documentElement().appendChild(timestamp);

    // write back updated xml content
    f.seek(0);
    QTextStream stream(&f);
#ifdef Q_WS_WIN
    /*
      the problem that on german systems umlauts are displayed as '?' for unknown (Qt'r related ?) reasons
      is caused by wrong encoding type conversations and has been fixed in kdelibs/kdoctools
      To have propper encoding tags in the xml file, QXmlDocument::save() is used.
    */
    doc.save(stream, 1, QDomNode::EncodingFromTextStream);

#else
    stream << doc.toString();
#endif
    f.close();
    fillTree();
}

void TOC::fillTree()
{
    QFile f(m_cacheFile);
    if (!f.open(QIODevice::ReadOnly))
        return;

    QDomDocument doc;
    if (!doc.setContent(&f))
        return;

    TOCChapterItem *chapItem = nullptr;
    QDomNodeList chapters = doc.documentElement().elementsByTagName(QStringLiteral("chapter"));
    for (int chapterCount = 0; chapterCount < chapters.count(); chapterCount++) {
        QDomElement chapElem = chapters.item(chapterCount).toElement();
        QDomElement chapTitleElem = childElement(chapElem, QStringLiteral("title"));
        QString chapTitle = chapTitleElem.text().simplified();
        QDomElement chapRefElem = childElement(chapElem, QStringLiteral("anchor"));
        QString chapRef = chapRefElem.text().trimmed();

        chapItem = new TOCChapterItem(this, m_parentItem, chapItem, chapTitle, chapRef);

        TOCSectionItem *sectItem = nullptr;
        QDomNodeList sections = chapElem.elementsByTagName(QStringLiteral("section"));
        for (int sectCount = 0; sectCount < sections.count(); sectCount++) {
            QDomElement sectElem = sections.item(sectCount).toElement();
            QDomElement sectTitleElem = childElement(sectElem, QStringLiteral("title"));
            const QString sectTitle = sectTitleElem.text().simplified();
            QDomElement sectRefElem = childElement(sectElem, QStringLiteral("anchor"));
            const QString sectRef = sectRefElem.text().trimmed();

            sectItem = new TOCSectionItem(this, chapItem, sectItem, sectTitle, sectRef);
        }
    }
}

QDomElement TOC::childElement(const QDomElement &element, const QString &name)
{
    QDomElement e;
    for (e = element.firstChild().toElement(); !e.isNull(); e = e.nextSibling().toElement())
        if (e.tagName() == name)
            break;
    return e;
}

void TOC::slotItemSelected(QTreeWidgetItem *item)
{
    TOCItem *tocItem;
    if ((tocItem = dynamic_cast<TOCItem *>(item)))
        Q_EMIT itemSelected(tocItem->entry()->url());

    item->setExpanded(!item->isExpanded());
}

TOCItem::TOCItem(TOC *toc, QTreeWidgetItem *parentItem, QTreeWidgetItem *after, const QString &text)
    : NavigatorItem(new DocEntry(text), parentItem, after)
{
    setAutoDeleteDocEntry(true);
    m_toc = toc;
}

TOCChapterItem::TOCChapterItem(TOC *toc, NavigatorItem *parent, QTreeWidgetItem *after, const QString &title, const QString &name)
    : TOCItem(toc, parent, after, title)
    , m_name(name)
{
    setExpanded(false);
    entry()->setUrl(url());
}

QString TOCChapterItem::url()
{
    return QLatin1String("help:") + toc()->application() + QLatin1Char('/') + m_name + QLatin1String(".html");
}

TOCSectionItem::TOCSectionItem(TOC *toc, TOCChapterItem *parent, QTreeWidgetItem *after, const QString &title, const QString &name)
    : TOCItem(toc, parent, after, title)
    , m_name(name)
{
    setIcon(0, QIcon::fromTheme(QStringLiteral("text-plain")));
    entry()->setUrl(url());
}

QString TOCSectionItem::url()
{
    if (static_cast<TOCSectionItem *>(parent()->child(0)) == this)
        return static_cast<TOCChapterItem *>(parent())->url() + QLatin1Char('#') + m_name;

    return QStringLiteral("help:") + toc()->application() + QLatin1Char('/') + m_name + QStringLiteral(".html");
}

#include "moc_toc.cpp"

// vim:ts=2:sw=2:et