/* -*- mode: c++; c-basic-offset:4 -*-
    commands/changeroottrustcommand.cpp

    This file is part of Kleopatra, the KDE keymanager
    Copyright (c) 2010 Klarälvdalens Datakonsult AB

    Kleopatra 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 2 of the License, or
    (at your option) any later version.

    Kleopatra 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

    In addition, as a special exception, the copyright holders give
    permission to link the code of this program with any edition of
    the Qt library by Trolltech AS, Norway (or with modified versions
    of Qt that use the same license as Qt), and distribute linked
    combinations including the two.  You must obey the GNU General
    Public License in all respects for all of the code used other than
    Qt.  If you modify this file, you may extend this exception to
    your version of the file, but you are not obligated to do so.  If
    you do not wish to do so, delete this exception statement from
    your version.
*/

#include <config-kleopatra.h>

#include "changeroottrustcommand.h"
#include "command_p.h"

#include <Libkleo/KeyCache>

#include <utils/gnupg-helper.h>

#include "kleopatra_debug.h"
#include <KLocalizedString>
#include <QSaveFile>

#include <QRegExp>
#include <QThread>
#include <QMutex>
#include <QMutexLocker>
#include <QString>
#include <QStringList>
#include <QByteArray>
#include <QFile>
#include <QDir>
#include <QProcess>

#include <gpgme++/key.h>

#include <cassert>

using namespace Kleo;
using namespace Kleo::Commands;
using namespace GpgME;

class ChangeRootTrustCommand::Private : public QThread, public Command::Private
{
    Q_OBJECT
private:
    friend class ::Kleo::Commands::ChangeRootTrustCommand;
    ChangeRootTrustCommand *q_func() const
    {
        return static_cast<ChangeRootTrustCommand *>(q);
    }
public:
    explicit Private(ChangeRootTrustCommand *qq, KeyListController *c)
        : QThread(), Command::Private(qq, c),
          mutex(),
          trust(Key::Ultimate),
          trustListFile(QDir(gnupgHomeDirectory()).absoluteFilePath(QStringLiteral("trustlist.txt"))),
          canceled(false)
    {

    }

private:
    void init()
    {
        q->setWarnWhenRunningAtShutdown(false);
        connect(this, SIGNAL(finished()), q_func(), SLOT(slotOperationFinished()));
    }

    void run() Q_DECL_OVERRIDE;

private:
    void slotOperationFinished()
    {
        KeyCache::mutableInstance()->enableFileSystemWatcher(true);
        if (error.isEmpty()) {
            KeyCache::mutableInstance()->reload(GpgME::CMS);
        } else
            Command::Private::error(i18n("Failed to update the trust database:\n"
                                         "%1", error),
                                    i18n("Root Trust Update Failed"));
        Command::Private::finished();
    }

private:
    mutable QMutex mutex;
    Key::OwnerTrust trust;
    QString trustListFile;
    QString gpgConfPath;
    QString error;
    volatile bool canceled;
};

ChangeRootTrustCommand::Private *ChangeRootTrustCommand::d_func()
{
    return static_cast<Private *>(d.get());
}
const ChangeRootTrustCommand::Private *ChangeRootTrustCommand::d_func() const
{
    return static_cast<const Private *>(d.get());
}

#define q q_func()
#define d d_func()

ChangeRootTrustCommand::ChangeRootTrustCommand(KeyListController *p)
    : Command(new Private(this, p))
{
    d->init();
}

ChangeRootTrustCommand::ChangeRootTrustCommand(QAbstractItemView *v, KeyListController *p)
    : Command(v, new Private(this, p))
{
    d->init();
}

ChangeRootTrustCommand::ChangeRootTrustCommand(const Key &key, KeyListController *p)
    : Command(new Private(this, p))
{
    assert(!key.isNull());
    d->init();
    setKey(key);
}

ChangeRootTrustCommand::ChangeRootTrustCommand(const Key &key, QAbstractItemView *v, KeyListController *p)
    : Command(v, new Private(this, p))
{
    assert(!key.isNull());
    d->init();
    setKey(key);
}

ChangeRootTrustCommand::~ChangeRootTrustCommand() {}

void ChangeRootTrustCommand::setTrust(Key::OwnerTrust trust)
{
    assert(!d->isRunning());
    const QMutexLocker locker(&d->mutex);
    d->trust = trust;
}

Key::OwnerTrust ChangeRootTrustCommand::trust() const
{
    const QMutexLocker locker(&d->mutex);
    return d->trust;
}

void ChangeRootTrustCommand::setTrustListFile(const QString &trustListFile)
{
    assert(!d->isRunning());
    const QMutexLocker locker(&d->mutex);
    d->trustListFile = trustListFile;
}

QString ChangeRootTrustCommand::trustListFile() const
{
    const QMutexLocker locker(&d->mutex);
    return d->trustListFile;
}

void ChangeRootTrustCommand::doStart()
{
    const std::vector<Key> keys = d->keys();
    Key key;
    if (keys.size() == 1) {
        key = keys.front();
    } else {
        qCWarning(KLEOPATRA_LOG) << "can only work with one certificate at a time";
    }

    if (key.isNull()) {
        d->Command::Private::finished();
        return;
    }

    d->gpgConfPath = gpgConfPath();
    KeyCache::mutableInstance()->enableFileSystemWatcher(false);
    d->start();
}

void ChangeRootTrustCommand::doCancel()
{
    const QMutexLocker locker(&d->mutex);
    d->canceled = true;
}

static QString change_trust_file(const QString &trustListFile, const QString &key, Key::OwnerTrust trust);
static QString run_gpgconf_reload_gpg_agent(const QString &gpgConfPath);

void ChangeRootTrustCommand::Private::run()
{

    QMutexLocker locker(&mutex);

    const QString key = QString::fromLatin1(keys().front().primaryFingerprint());
    const Key::OwnerTrust trust = this->trust;
    const QString trustListFile = this->trustListFile;
    const QString gpgConfPath   = this->gpgConfPath;

    locker.unlock();

    QString err = change_trust_file(trustListFile, key, trust);
    if (err.isEmpty()) {
        err = run_gpgconf_reload_gpg_agent(gpgConfPath);
    }

    locker.relock();

    this->error = err;

}

static QString add_colons(const QString &fpr)
{
    QString result;
    result.reserve(fpr.size() / 2 * 3 + 1);
    bool needColon = false;
    for (QChar ch : fpr) {
        result += ch;
        if (needColon) {
            result += QLatin1Char(':');
        }
        needColon = !needColon;
    }
    if (result.endsWith(QLatin1Char(':'))) {
        result.chop(1);
    }
    return result;
}

namespace
{

// fix stupid default-finalize behaviour...
class KFixedSaveFile : public QSaveFile
{
public:
    explicit KFixedSaveFile(const QString &fileName)
        : QSaveFile(fileName) {}
    ~KFixedSaveFile()
    {
        cancelWriting();
    }

};

}

// static
QString change_trust_file(const QString &trustListFile, const QString &key, Key::OwnerTrust trust)
{
    QList<QByteArray> trustListFileContents;

    {
        QFile in(trustListFile);
        if (in.exists()) {  // non-existence is not fatal...
            if (in.open(QIODevice::ReadOnly)) {
                trustListFileContents = in.readAll().split('\n');
            } else { // ...but failure to open an existing file _is_
                return i18n("Cannot open existing file \"%1\" for reading: %2",
                            trustListFile, in.errorString());
            }
        }
        // close, so KSaveFile doesn't clobber the original
    }

    KFixedSaveFile out(trustListFile);
    if (!out.open(QIODevice::WriteOnly))
        return i18n("Cannot open file \"%1\" for reading and writing: %2",
                    out.fileName() /*sic!*/, out.errorString());

    if (!out.setPermissions(QFile::ReadOwner | QFile::WriteOwner))
        return i18n("Cannot set restrictive permissions on file %1: %2",
                    out.fileName() /*sic!*/, out.errorString());

    const QString keyColon = add_colons(key);

    qCDebug(KLEOPATRA_LOG) << qPrintable(key) << " -> " << qPrintable(keyColon);

    //               ( 1)    (                         2                           )    (  3  )( 4)
    QRegExp rx(QLatin1String("\\s*(!?)\\s*([a-fA-F0-9]{40}|(?:[a-fA-F0-9]{2}:){19}[a-fA-F0-9]{2})\\s*([SsPp*])(.*)"));
    bool found = false;

    Q_FOREACH (const QByteArray &rawLine, trustListFileContents) {

        const QString line = QString::fromLatin1(rawLine.data(), rawLine.size());
        if (!rx.exactMatch(line)) {
            qCDebug(KLEOPATRA_LOG) << "line \"" << rawLine.data() << "\" does not match";
            out.write(rawLine + '\n');
            continue;
        }
        const QString cap2 = rx.cap(2);
        if (cap2 != key && cap2 != keyColon) {
            qCDebug(KLEOPATRA_LOG) << qPrintable(key) << " != "
                                   << qPrintable(cap2) << " != "
                                   << qPrintable(keyColon);
            out.write(rawLine + '\n');
            continue;
        }
        found = true;
        const bool disabled = rx.cap(1) == QLatin1String("!");
        const QByteArray flags = rx.cap(3).toLatin1();
        const QByteArray rests = rx.cap(4).toLatin1();
        if (trust == Key::Ultimate)
            if (!disabled) { // unchanged
                out.write(rawLine + '\n');
            } else {
                out.write(keyColon.toLatin1() + ' ' + flags + rests + '\n');
            }
        else if (trust == Key::Never) {
            if (disabled) { // unchanged
                out.write(rawLine + '\n');
            } else {
                out.write('!' + keyColon.toLatin1() + ' ' + flags + rests + '\n');
            }
        }
        // else: trust == Key::Unknown
        // -> don't write - ie.erase
    }

    if (!found) {  // add
        if (trust == Key::Ultimate) {
            out.write(keyColon.toLatin1() + ' ' + 'S' + '\n');
        } else if (trust == Key::Never) {
            out.write('!' + keyColon.toLatin1() + ' ' + 'S' + '\n');
        }
    }

    if (!out.commit())
        return i18n("Failed to move file %1 to its final destination, %2: %3",
                    out.fileName(), trustListFile, out.errorString());

    return QString();

}

// static
QString run_gpgconf_reload_gpg_agent(const QString &gpgConfPath)
{
    if (gpgConfPath.isEmpty()) {
        return i18n("Could not find gpgconf executable");
    }

    QProcess p;
    p.start(gpgConfPath, QStringList() << QStringLiteral("--reload") << QStringLiteral("gpg-agent"));
    qCDebug(KLEOPATRA_LOG) <<  "starting " << qPrintable(gpgConfPath)
                           << " --reload gpg-agent";
    p.waitForFinished(-1);
    qCDebug(KLEOPATRA_LOG) << "done";
    if (p.error() == QProcess::UnknownError) {
        return QString();
    } else {
        return i18n("\"gpgconf --reload gpg-agent\" failed: %1", p.errorString());
    }
}

#undef q_func
#undef d_func

#include "moc_changeroottrustcommand.cpp"
#include "changeroottrustcommand.moc"
