/** -*- c++ -*-
 * overlaywidget.h
 *
 *  Copyright (c) 2004 David Faure <faure@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, 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 "overlaywidget.h"
#include <QHBoxLayout>
#include <QResizeEvent>
#include <QEvent>

using namespace KPIM;

class KPIM::OverlayWidgetPrivate
{
public:
    OverlayWidgetPrivate()
    {
    }

    QWidget *mAlignWidget = nullptr;
};

OverlayWidget::OverlayWidget(QWidget *alignWidget, QWidget *parent)
    : QFrame(parent)
    , d(new KPIM::OverlayWidgetPrivate)
{
    setAlignWidget(alignWidget);
    setLayout(new QHBoxLayout(this));
}

OverlayWidget::~OverlayWidget()
{
    delete d;
}

QWidget *OverlayWidget::alignWidget() const
{
    return d->mAlignWidget;
}

void OverlayWidget::reposition()
{
    if (!d->mAlignWidget) {
        return;
    }
    // p is in the alignWidget's coordinates
    QPoint p;
    // We are always above the alignWidget, right-aligned with it for
    // LTR locales, and left-aligned for RTL locales (default value=0).
    if (layoutDirection() == Qt::LeftToRight) {
        p.setX(d->mAlignWidget->width() - width());
    }
    p.setY(-height());
    // Position in the toplevelwidget's coordinates
    QPoint pTopLevel = d->mAlignWidget->mapTo(topLevelWidget(), p);
    // Position in the widget's parentWidget coordinates
    QPoint pParent = parentWidget()->mapFrom(topLevelWidget(), pTopLevel);
    // Move 'this' to that position.
    move(pParent);
}

void OverlayWidget::setAlignWidget(QWidget *w)
{
    if (w == d->mAlignWidget) {
        return;
    }

    if (d->mAlignWidget) {
        d->mAlignWidget->removeEventFilter(this);
    }

    d->mAlignWidget = w;

    if (d->mAlignWidget) {
        d->mAlignWidget->installEventFilter(this);
    }

    reposition();
}

bool OverlayWidget::eventFilter(QObject *o, QEvent *e)
{
    if (o == d->mAlignWidget
        && (e->type() == QEvent::Move || e->type() == QEvent::Resize)) {
        reposition();
    }
    return QFrame::eventFilter(o, e);
}

void OverlayWidget::resizeEvent(QResizeEvent *ev)
{
    reposition();
    QFrame::resizeEvent(ev);
}
