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

Copyright (C) 2006 Lubos Lunak <l.lunak@kde.org>
Copyright (C) 2010, 2011, 2017 Martin Gräßlin <mgraesslin@kde.org>

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/>.
*********************************************************************/
#include "effects_x11.h"
#include "effects_mouse_interception_x11_filter.h"
#include "cursor.h"
#include "screenedge.h"
#include "screens.h"
#include "utils.h"
#include "workspace.h"

#include <QDesktopWidget>

namespace KWin
{

EffectsHandlerImplX11::EffectsHandlerImplX11(Compositor *compositor, Scene *scene)
    : EffectsHandlerImpl(compositor, scene)
{
    connect(this, &EffectsHandlerImpl::screenGeometryChanged, this,
        [this] (const QSize &size) {
            if (m_mouseInterceptionWindow.isValid()) {
                m_mouseInterceptionWindow.setGeometry(QRect(0, 0, size.width(), size.height()));
            }
        }
    );
}

EffectsHandlerImplX11::~EffectsHandlerImplX11()
{
    // EffectsHandlerImpl tries to unload all effects when it's destroyed.
    // The routine that unloads effects makes some calls (indirectly) to
    // doUngrabKeyboard and doStopMouseInterception, which are virtual.
    // Given that any call to a virtual function in the destructor of a base
    // class will never go to a derived class, we have to unload effects
    // here. Yeah, this is quite a bit ugly but it's fine; someday, X11
    // will be dead (or not?).
    unloadAllEffects();
}

bool EffectsHandlerImplX11::doGrabKeyboard()
{
    bool ret = grabXKeyboard();
    if (!ret)
        return false;
    // Workaround for Qt 5.9 regression introduced with 2b34aefcf02f09253473b096eb4faffd3e62b5f4
    // we no longer get any events for the root window, one needs to call winId() on the desktop window
    // TODO: change effects event handling to create the appropriate QKeyEvent without relying on Qt
    // as it's done already in the Wayland case.
    qApp->desktop()->winId();
    return ret;
}

void EffectsHandlerImplX11::doUngrabKeyboard()
{
    ungrabXKeyboard();
}

void EffectsHandlerImplX11::doStartMouseInterception(Qt::CursorShape shape)
{
    // NOTE: it is intended to not perform an XPointerGrab on X11. See documentation in kwineffects.h
    // The mouse grab is implemented by using a full screen input only window
    if (!m_mouseInterceptionWindow.isValid()) {
        const QSize &s = screens()->size();
        const QRect geo(0, 0, s.width(), s.height());
        const uint32_t mask = XCB_CW_OVERRIDE_REDIRECT | XCB_CW_EVENT_MASK;
        const uint32_t values[] = {
            true,
            XCB_EVENT_MASK_BUTTON_PRESS | XCB_EVENT_MASK_BUTTON_RELEASE | XCB_EVENT_MASK_POINTER_MOTION
        };
        m_mouseInterceptionWindow.reset(Xcb::createInputWindow(geo, mask, values));
        defineCursor(shape);
    } else {
        defineCursor(shape);
    }
    m_mouseInterceptionWindow.map();
    m_mouseInterceptionWindow.raise();
    m_x11MouseInterception = std::make_unique<EffectsMouseInterceptionX11Filter>(m_mouseInterceptionWindow, this);
    // Raise electric border windows above the input windows
    // so they can still be triggered.
    ScreenEdges::self()->ensureOnTop();
}

void EffectsHandlerImplX11::doStopMouseInterception()
{
    m_mouseInterceptionWindow.unmap();
    m_x11MouseInterception.reset();
    Workspace::self()->stackScreenEdgesUnderOverrideRedirect();
}

void EffectsHandlerImplX11::defineCursor(Qt::CursorShape shape)
{
    const xcb_cursor_t c = Cursors::self()->mouse()->x11Cursor(shape);
    if (c != XCB_CURSOR_NONE) {
        m_mouseInterceptionWindow.defineCursor(c);
    }
}

void EffectsHandlerImplX11::doCheckInputWindowStacking()
{
    m_mouseInterceptionWindow.raise();
    // Raise electric border windows above the input windows
    // so they can still be triggered. TODO: Do both at once.
    ScreenEdges::self()->ensureOnTop();
}

}
