/********************************************************************
 KWin - the KDE window manager
 This file is part of the KDE project.

Copyright 2019 Roman Gilg <subdiff@gmail.com>

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, see <http://www.gnu.org/licenses/>.
*********************************************************************/
#ifndef KWIN_XWL_SELECTION_SOURCE
#define KWIN_XWL_SELECTION_SOURCE

#include <QObject>
#include <QVector>

#include <xcb/xcb.h>

class QSocketNotifier;

struct xcb_selection_request_event_t;
struct xcb_xfixes_selection_notify_event_t;

namespace KWayland
{
namespace Client
{
class DataSource;
}
namespace Server
{
class DataDeviceInterface;
class DataSourceInterface;
}
}

namespace KWin
{
namespace Xwl
{
class Selection;

/**
 * Base class representing a data source.
 **/
class SelectionSource : public QObject
{
    Q_OBJECT

public:
    SelectionSource(Selection *selection);

    xcb_timestamp_t timestamp() const {
        return m_timestamp;
    }
    void setTimestamp(xcb_timestamp_t time) {
        m_timestamp = time;
    }

protected:
    Selection *selection() const {
        return m_selection;
    }
    void setWindow(xcb_window_t window) {
        m_window = window;
    }
    xcb_window_t window() const {
        return m_window;
    }

private:
    xcb_timestamp_t m_timestamp = XCB_CURRENT_TIME;
    Selection *m_selection;
    xcb_window_t m_window;

    Q_DISABLE_COPY(SelectionSource)
};

/**
 * Representing a Wayland native data source.
 **/
class WlSource : public SelectionSource
{
    Q_OBJECT

public:
    WlSource(Selection *selection, KWayland::Server::DataDeviceInterface *ddi);
    void setDataSourceIface(KWayland::Server::DataSourceInterface *dsi);

    bool handleSelectionRequest(xcb_selection_request_event_t *event);
    void sendTargets(xcb_selection_request_event_t *event);
    void sendTimestamp(xcb_selection_request_event_t *event);

    void receiveOffer(const QString &mime);
    void sendSelectionNotify(xcb_selection_request_event_t *event, bool success);

Q_SIGNALS:
    void transferReady(xcb_selection_request_event_t *event, qint32 fd);

private:
    bool checkStartTransfer(xcb_selection_request_event_t *event);

    KWayland::Server::DataDeviceInterface *m_ddi = nullptr;
    KWayland::Server::DataSourceInterface *m_dsi = nullptr;

    QVector<QString> m_offers;
    QMetaObject::Connection m_offerConnection;

    Q_DISABLE_COPY(WlSource)
};

using Mimes = QVector<QPair<QString, xcb_atom_t> >;

/**
 * Representing an X data source.
 **/
class X11Source : public SelectionSource
{
    Q_OBJECT

public:
    X11Source(Selection *selection, xcb_xfixes_selection_notify_event_t *event);

    /**
     * @param ds must exist.
     *
     * X11Source does not take ownership of it in general, but if the function
     * is called again, it will delete the previous data source.
     **/
    void setDataSource(KWayland::Client::DataSource *dataSource);
    KWayland::Client::DataSource *dataSource() const {
        return m_dataSource;
    }
    void getTargets();

    Mimes offers() const {
        return m_offers;
    }
    void setOffers(const Mimes &offers);

    bool handleSelectionNotify(xcb_selection_notify_event_t *event);

    void setRequestor(xcb_window_t window) {
        setWindow(window);
    }

Q_SIGNALS:
    void offersChanged(const QStringList &added, const QStringList &removed);
    void transferReady(xcb_atom_t target, qint32 fd);

private:
    void handleTargets();
    void startTransfer(const QString &mimeName, qint32 fd);

    xcb_window_t m_owner;
    KWayland::Client::DataSource *m_dataSource = nullptr;

    Mimes m_offers;

    Q_DISABLE_COPY(X11Source)
};

} // namespace Xwl
} // namespace KWin

#endif