/*
 *   Copyright 2007 by Dan Meltzer <hydrogen@notyetimplemented.com>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Library General Public License as
 *   published by the Free Software Foundation; either version 2, 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 Library 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.
 */
#include "tooltip_p.h"

#include <QHBoxLayout>
#include <QLabel>
#include <QPixmap>
#include <QTimer>
#include <QGraphicsView>
#include <QX11Info>

#include <kglobal.h>
#include <kwindowsystem.h>

#include <X11/Xlib.h>
#include <fixx11h.h>

namespace Plasma {

class ToolTip::Private
{
    public:
        Private()
        : label(0)
        , imageLabel(0)
        , preview(0)
        , windowToPreview(0)
        , currentWidget(0)
        , isShown(false)
        , showTimer(0)
        , hideTimer(0)
    { }

    QLabel *label;
    QLabel *imageLabel;
    WindowPreview *preview;
    WId windowToPreview;
    Plasma::Widget *currentWidget;
    bool isShown;
    QTimer *showTimer;
    QTimer *hideTimer;
};

class ToolTipSingleton
{
    public:
        ToolTip self;
};
K_GLOBAL_STATIC( ToolTipSingleton, privateInstance )

ToolTip *ToolTip::instance()
{
    return &privateInstance->self;
}

void ToolTip::show(const QPoint &location, Plasma::Widget *widget)
{
    d->currentWidget = widget;
    setData(widget->toolTip());
    move(location.x(), location.y() - sizeHint().height());
    if (d->isShown) {
        // Don't delay if the tooltip is already shown(i.e. moving from one task to another)
        // Qt doesn't seem to like visible tooltips moving though, so hide it and then
        // immediately show it again
        setVisible(false);
        d->showTimer->start(0);
    } else {
        d->showTimer->start(1000);  //Shown after a one second delay.
    }
}

void ToolTip::hide()
{
    d->currentWidget = 0;
    d->showTimer->stop();  //Mouse out, stop the timer to show the tooltip
    if (!isVisible()) {
        d->isShown = false;
    }
    setVisible(false);
    d->hideTimer->start(500);  //500 ms delay before we are officially "gone" to allow for the time to move between widgets
}

Plasma::Widget *ToolTip::currentWidget() const
{
    return d->currentWidget;
}

//PRIVATE FUNCTIONS
void ToolTip::slotShowToolTip()
{
    QGraphicsView *v = d->currentWidget->view();
    if (v && v->mouseGrabber()) {
	return;
    }

    d->isShown = true;  //ToolTip is visible
    setVisible(true);
}

void ToolTip::slotResetTimer()
{
    if (!isVisible()) { //One might have moused out and back in again
        d->isShown = false;
    }
}

void ToolTip::showEvent( QShowEvent* e )
{
    QWidget::showEvent( e );
    if( d->windowToPreview != 0 ) { //show or hide the window preview area
        d->preview->show();
        d->preview->setInfo();
    } else
        d->preview->hide();
}

ToolTip::ToolTip()
    : QWidget(0)
    , d( new Private )
{
    setWindowFlags(Qt::ToolTip);
    QGridLayout *l = new QGridLayout;
    d->preview = new WindowPreview;
    d->label = new QLabel;
    d->label->setWordWrap(true);
    d->imageLabel = new QLabel;
    d->imageLabel->setAlignment(Qt::AlignTop | Qt::AlignLeft);
    l->addWidget(d->preview, 0, 0, 1, 2);
    l->addWidget(d->imageLabel, 1, 0);
    l->addWidget(d->label, 1, 1);
    setLayout(l);

    d->showTimer = new QTimer(this);
    d->showTimer->setSingleShot(true);
    d->hideTimer = new QTimer(this);
    d->hideTimer->setSingleShot(true);

    connect(d->showTimer, SIGNAL(timeout()), SLOT(slotShowToolTip()));
    connect(d->hideTimer, SIGNAL(timeout()), SLOT(slotResetTimer()));
}

void ToolTip::setData(const Plasma::ToolTipData &data)
{
    d->label->setText("<qt><h3>" + data.mainText + "</h3><p>" +
                        data.subText + "</p></qt>");
    d->imageLabel->setPixmap(data.image);
    d->preview->setWindowId( data.windowToPreview );
}

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


// A widget which reserves area for window preview and sets hints on the toplevel
// tooltip widget that tells KWin to render the preview in this area. This depends
// on KWin's TaskbarThumbnail compositing effect (which is here detected).

void WindowPreview::setWindowId( WId w )
{
    if( !previewsAvailable()) {
        id = 0;
        return;
    }
    id = w;
    windowSize = QSize();
}

bool WindowPreview::previewsAvailable() const
{
    if( !KWindowSystem::compositingActive())
        return false;
    // hackish way to find out if KWin has the effect enabled,
    // TODO provide proper support
    Display* dpy = QX11Info::display();
    Atom atom = XInternAtom( dpy, "_KDE_WINDOW_PREVIEW", False );
    int cnt;
    Atom* list = XListProperties( dpy, DefaultRootWindow( dpy ), &cnt );
    if( list != NULL ) {
        bool ret = ( qFind( list, list + cnt, atom ) != list + cnt );
        XFree( list );
        return ret;
    }
    return false;
}

QSize WindowPreview::sizeHint() const
{
    if( id == 0 )
        return QSize();
    if( !windowSize.isValid())
        readWindowSize();
    QSize s = windowSize;
    s.scale( 200, 150, Qt::KeepAspectRatio );
    return s;
}

void WindowPreview::readWindowSize() const
{
    Window r;
    int x, y;
    unsigned int w, h, b, d;
    if( XGetGeometry( QX11Info::display(), id, &r, &x, &y, &w, &h, &b, &d ))
        windowSize = QSize( w, h );
    else
        windowSize = QSize();
}

void WindowPreview::setInfo()
{
    Display* dpy = QX11Info::display();
    Atom atom = XInternAtom( dpy, "_KDE_WINDOW_PREVIEW", False );
    if( id == 0 ) {
        XDeleteProperty( dpy, winId(), atom );
        return;
    }
    if( !windowSize.isValid())
        readWindowSize();
    if( !windowSize.isValid()) {
        XDeleteProperty( dpy, winId(), atom );
        return;
    }
    Q_ASSERT( parentWidget()->isWindow()); // parent must be toplevel
    long data[] = { 1, 5, id, x(), y(), width(), height() };
    XChangeProperty( dpy, parentWidget()->winId(), atom, atom, 32, PropModeReplace,
        reinterpret_cast< unsigned char* >( data ), sizeof( data ) / sizeof( data[ 0 ] ));
}

}
#include "tooltip_p.moc"