/****************************************************************************
**
** Copyright (C) 1992-2005 Trolltech AS. All rights reserved.
**
** This file is part of the gui module of the Qt Toolkit.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
** information about Qt Commercial License Agreements.
** See http://www.trolltech.com/gpl/ for GPL licensing information.
**
** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/

#include "qshortcut.h"
#include "private/qwidget_p.h"

#include <qevent.h>
#include <qwhatsthis.h>
#include <qmenu.h>
#include <qapplication.h>
#include <private/qapplication_p.h>
#include <private/qshortcutmap_p.h>

/*!
    \class QShortcut
    \brief The QShortcut class is used to create keyboard shortcuts.

    \ingroup events
    \mainclass

    The QShortcut class provides a way of connecting keyboard
    shortcuts to Qt's \l{signals and slots} mechanism, so that
    objects can be informed when a shortcut is executed. The shortcut
    can be set up to contain all the key presses necessary to
    describe a keyboard shortcut, including the states of modifier
    keys such as \gui Shift, \gui Ctrl, and \gui Alt.

    For applications that use menus, it may be more convenient to
    use the convenience functions provided in the QMenu class to
    assign keyboard shortcuts to menu items as they are created.
    Alternatively, shortcuts may be associated with other types of
    actions in the QAction class.

    The simplest way to create a shortcut for a particular widget is
    to construct the shortcut with a key sequence. For example:

    \code
        shortcut = QShortcut(QKeySequence(tr("Ctrl+O", "File|Open")),
                             parent);
    \endcode

    When the user types the \l{QKeySequence}{key sequence}
    for a given shortcut, the shortcut's activated() signal is
    emitted. (In the case of ambiguity, the activatedAmbiguously()
    signal is emitted.) A shortcut is "listened for" by Qt's event
    loop when the shortcut's parent widget is receiving events.

    A shortcut's key sequence can be set with setKey() and retrieved
    with key(). A shortcut can be enabled or disabled with
    setEnabled(), and can have "What's This?" help text set with
    setWhatsThis().

    \sa QShortcutEvent, QKeySequence, QAction
*/

/*!
    \fn QWidget *QShortcut::parentWidget() const

    Returns the shortcut's parent widget.
*/

/*!
    \fn void QShortcut::activated()

    This signal is emitted when the user types the shortcut's key
    sequence.

    \sa activatedAmbiguously()
*/

/*!
    \fn void QShortcut::activatedAmbiguously()

    This signal is emitted when the user types a shortcut key
    sequence that is ambiguous. For example, if one key sequence is a
    "prefix" for another and the user types these keys it isn't clear
    if they want the shorter key sequence, or if they're about to type
    more to complete the longer key sequence.

    \sa activated()
*/

/*
    \internal
    Private data accessed through d-pointer.
*/
class QShortcutPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QShortcut)
public:
    QShortcutPrivate() : sc_context(Qt::WindowShortcut), sc_enabled(true), sc_id(0) {}
    QKeySequence sc_sequence;
    Qt::ShortcutContext sc_context;
    bool sc_enabled;
    int sc_id;
    QString sc_whatsthis;
    void redoGrab(QShortcutMap &map);
};

void QShortcutPrivate::redoGrab(QShortcutMap &map)
{
    Q_Q(QShortcut);
    QWidget *parent = q->parentWidget();
    if (!parent) {
        qWarning("QShortcut: no widget parent defined");
        return;
    }

    if (sc_id)
        map.removeShortcut(sc_id, q);
    if (sc_sequence.isEmpty())
        return;
    sc_id = map.addShortcut(q, sc_sequence, sc_context);
    if (!sc_enabled)
        map.setShortcutEnabled(false, sc_id, q);
}

/*!
    Constructs a QShortcut object for the \a parent widget. Since no
    shortcut key sequence is specified, the shortcut will not emit any
    signals.

    \sa setKey()
*/
QShortcut::QShortcut(QWidget *parent)
    : QObject(*new QShortcutPrivate, parent)
{
    Q_ASSERT(parent != 0);
}

/*!
    Constructs a QShortcut object for the \a parent widget. The shortcut
    operates on its parent, listening for \l{QShortcutEvent}s that
    match the \a key sequence. Depending on the ambiguity of the
    event, the shortcut will call the \a member function, or the \a
    ambiguousMember function, if the key press was in the shortcut's
    \a context.
*/
QShortcut::QShortcut(const QKeySequence &key, QWidget *parent,
                     const char *member, const char *ambiguousMember,
                     Qt::ShortcutContext context)
    : QObject(*new QShortcutPrivate, parent)
{
    Q_D(QShortcut);
    Q_ASSERT(parent != 0);
    d->sc_context = context;
    d->sc_sequence = key;
    d->redoGrab(qApp->d_func()->shortcutMap);
    if (member)
        connect(this, SIGNAL(activated()), parent, member);
    if (ambiguousMember)
        connect(this, SIGNAL(activatedAmbiguously()), parent, ambiguousMember);
}

/*!
    Destroys the shortcut.
*/
QShortcut::~QShortcut()
{
    Q_D(QShortcut);
    if (qApp)
        qApp->d_func()->shortcutMap.removeShortcut(d->sc_id, this);
}

/*!
    \property QShortcut::key
    \brief the shortcut's key sequence

    This is a key sequence with an optional combination of Shift, Ctrl,
    and Alt. The key sequence may be supplied in a number of ways:

    \code
        setKey(0);                  // no signal emitted
        setKey(QKeySequence());     // no signal emitted
        setKey(0x3b1);              // Greek letter alpha
        setKey(Qt::Key_D);              // 'd', e.g. to delete
        setKey('q');                // 'q', e.g. to quit
        setKey(Qt::CTRL + Qt::Key_P);       // Ctrl+P, e.g. to print document
        setKey("Ctrl+P");           // Ctrl+P, e.g. to print document
    \endcode
*/
void QShortcut::setKey(const QKeySequence &key)
{
    Q_D(QShortcut);
    if (d->sc_sequence == key)
        return;
    d->sc_sequence = key;
    d->redoGrab(qApp->d_func()->shortcutMap);
}

QKeySequence QShortcut::key() const
{
    Q_D(const QShortcut);
    return d->sc_sequence;
}

/*!
    \property QShortcut::enabled
    \brief whether the shortcut is enabled

    An enabled shortcut emits the activated() or activatedAmbiguously()
    signal when a QShortcutEvent occurs that matches the shortcut's
    key() sequence.

    If the application is in \c WhatsThis mode the shortcut will not emit
    the signals, but will show the "What's This?" text instead.

    \sa whatsThis
*/
void QShortcut::setEnabled(bool enable)
{
    Q_D(QShortcut);
    if (d->sc_enabled == enable)
        return;
    d->sc_enabled = enable;
    qApp->d_func()->shortcutMap.setShortcutEnabled(enable, d->sc_id, this);
}

bool QShortcut::isEnabled() const
{
    Q_D(const QShortcut);
    return d->sc_enabled;
}

/*!
    \property QShortcut::context
    \brief the context in which the shortcut is valid

    A shortcut's context decides in which circumstances a shortcut is
    allowed to be triggered. The normal context is Qt::WindowShortcut,
    which allows the shortcut to trigger if the parent (the widget
    containing the shortcut) is a subwidget of the active top-level
    window.
*/
void QShortcut::setContext(Qt::ShortcutContext context)
{
    Q_D(QShortcut);
    if(d->sc_context == context)
        return;
    d->sc_context = context;
    d->redoGrab(qApp->d_func()->shortcutMap);
}

Qt::ShortcutContext QShortcut::context()
{
    Q_D(QShortcut);
    return d->sc_context;
}

/*!
    \property QShortcut::whatsThis
    \brief the shortcut's "What's This?" help text

    The text will be shown when the application is in "What's
    This?" mode and the user types the shortcut key() sequence.

    To set "What's This?" help on a menu item (with or without a
    shortcut key), set the help on the item's action.

    \sa QWhatsThis::inWhatsThisMode(), QAction::setWhatsThis()
*/
void QShortcut::setWhatsThis(const QString &text)
{
    Q_D(QShortcut);
    d->sc_whatsthis = text;
}

QString QShortcut::whatsThis() const
{
    Q_D(const QShortcut);
    return d->sc_whatsthis;
}

/*!
    Returns the shortcut's ID.

    \sa QShortcutEvent::shortcutId()
*/
int QShortcut::id() const
{
    Q_D(const QShortcut);
    return d->sc_id;
}

/*!
    \internal
*/
bool QShortcut::event(QEvent *e)
{
    Q_D(QShortcut);
    bool handled = false;
    if (d->sc_enabled && e->type() == QEvent::Shortcut) {
        QShortcutEvent *se = static_cast<QShortcutEvent *>(e);
        if (se->shortcutId() == d->sc_id && se->key() == d->sc_sequence){
#ifndef QT_NO_WHATSTHIS
            if (QWhatsThis::inWhatsThisMode()) {
                QWhatsThis::showText(QCursor::pos(), d->sc_whatsthis);
                handled = true;
            } else
#endif
            if (se->isAmbiguous())
                emit activatedAmbiguously();
            else
                emit activated();
            handled = true;
        }
    }
    return handled;
}
