/*
 * Bittorrent Client using Qt and libtorrent.
 * Copyright (C) 2020  Vladimir Golovnev <glassez@yandex.ru>
 *
 * This program 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.
 *
 * 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 Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * In addition, as a special exception, the copyright holders give permission to
 * link this program with the OpenSSL project's "OpenSSL" library (or with
 * modified versions of it that use the same license as the "OpenSSL" library),
 * and distribute the linked executables. You must obey the GNU General Public
 * License in all respects for all of the code used other than "OpenSSL".  If you
 * modify file(s), you may extend this exception to your version of the file(s),
 * but you are not obligated to do so. If you do not wish to do so, delete this
 * exception statement from your version.
 */

#include "nativetorrentextension.h"

#include <libtorrent/torrent_status.hpp>

namespace
{
    bool isPaused(const lt::torrent_status &torrentStatus)
    {
#if (LIBTORRENT_VERSION_NUM < 10200)
        return (torrentStatus.paused && !torrentStatus.auto_managed);
#else
        return ((torrentStatus.flags & lt::torrent_flags::paused)
                && !(torrentStatus.flags & lt::torrent_flags::auto_managed));
#endif
    }

    bool isAutoManaged(const lt::torrent_status &torrentStatus)
    {
#if (LIBTORRENT_VERSION_NUM < 10200)
        return torrentStatus.auto_managed;
#else
        return static_cast<bool>(torrentStatus.flags & lt::torrent_flags::auto_managed);
#endif
    }
}

NativeTorrentExtension::NativeTorrentExtension(const lt::torrent_handle &torrentHandle)
    : m_torrentHandle {torrentHandle}
{
}

// This method is called when state of torrent is changed
#if (LIBTORRENT_VERSION_NUM < 10200)
void NativeTorrentExtension::on_state(const int state)
#else
void NativeTorrentExtension::on_state(const lt::torrent_status::state_t state)
#endif
{
    // When a torrent enters "checking files" state while paused, we temporarily resume it
    // (really we just allow libtorrent to resume it by enabling auto management for it).
    if (state == lt::torrent_status::checking_files) {
        if (isPaused(m_torrentHandle.status({}))) {
#if (LIBTORRENT_VERSION_NUM < 10200)
            m_torrentHandle.stop_when_ready(true);
            m_torrentHandle.auto_managed(true);
#else
            m_torrentHandle.set_flags(lt::torrent_flags::stop_when_ready | lt::torrent_flags::auto_managed);
#endif
        }
    }
}

bool NativeTorrentExtension::on_pause()
{
    if (!isAutoManaged(m_torrentHandle.status({}))) {
#if (LIBTORRENT_VERSION_NUM < 10200)
        m_torrentHandle.stop_when_ready(false);
#else
        m_torrentHandle.unset_flags(lt::torrent_flags::stop_when_ready);
#endif
    }

    // return `false` to allow standard handler
    // and other extensions to be also invoked.
    return false;
}
