/****************************************************************************
**
** Copyright (C) 1992-2005 Trolltech AS. All rights reserved.
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file.  Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
** http://www.trolltech.com/products/qt/opensource.html
**
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://www.trolltech.com/products/qt/licensing.html or contact the
** sales department at sales@trolltech.com.
**
** 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 "qaccessiblewidget.h"

#ifndef QT_NO_ACCESSIBILITY

#include "qapplication.h"
#include "qgroupbox.h"
#include "qlabel.h"
#include "qtooltip.h"
#include "qwhatsthis.h"
#include "qwidget.h"

#include <math.h>

static QWidgetList childWidgets(const QWidget *widget)
{
    QObjectList list = widget->children();
    QWidgetList widgets;
    for (int i = 0; i < list.size(); ++i) {
        QWidget *w = qobject_cast<QWidget *>(list.at(i));
        if (w)
            widgets.append(w);
    }
    return widgets;
}

static QString buddyString(const QWidget *widget)
{
    if (!widget)
        return QString();
    QWidget *parent = widget->parentWidget();
    if (!parent)
        return QString();
#ifndef QT_NO_SHORTCUT
    QObjectList ol = parent->children();
    for (int i = 0; i < ol.size(); ++i) {
        QLabel *label = qobject_cast<QLabel*>(ol.at(i));
        if (label && label->buddy() == widget)
            return label->text();
    }
#endif

#ifndef QT_NO_GROUPBOX
    QGroupBox *groupbox = qobject_cast<QGroupBox*>(parent);
    if (groupbox)
        return groupbox->title();
#endif
    
    return QString();
}

QString Q_GUI_EXPORT qt_accStripAmp(const QString &text)
{
    if (text.isEmpty())
        return text;

    const QChar *ch = text.unicode();
    int length = text.length();
    QString str;
    while (length > 0) {
        if (*ch == '&') {
            ++ch;
            --length;
            if (!ch)
                --ch;
        }
        str += *ch;
        ++ch;
        --length;
    }
    return str;
}

QString Q_GUI_EXPORT qt_accHotKey(const QString &text)
{
#ifndef QT_NO_SHORTCUT
    if (text.isEmpty())
        return text;

    int fa = 0;
    QChar ac;
    while ((fa = text.indexOf('&', fa)) != -1) {
        if (fa == text.length() - 1 || text.at(fa+1) != '&') {
            ac = text.at(fa+1);
            break;
        }
    }
    if (ac.isNull())
        return QString();
    return (QString)QKeySequence(Qt::ALT) + ac.toUpper();
#else
    return QString();
#endif
}

class QAccessibleWidgetPrivate : public QAccessible
{
public:
    QAccessibleWidgetPrivate()
        :role(Client)
    {}

    Role role;
    QString name;
    QString description;
    QString value;
    QString help;
    QString accelerator;
    QStringList primarySignals;
    const QAccessibleInterface *asking;
};

/*!
    \class QAccessibleWidget
    \brief The QAccessibleWidget class implements the QAccessibleInterface for QWidgets.

    \ingroup accessibility

    This class is convenient to use as a base class for custom
    implementations of QAccessibleInterfaces that provide information
    about widget objects.

    The class provides functions to retrieve the parentObject() (the
    widget's parent widget), and the associated widget(). Controlling
    signals can be added with addControllingSignal(), and setters are
    provided for various aspects of the interface implementation, for
    example setValue(), setDescription(), setAccelerator(), and
    setHelp().

    \sa QAccessible, QAccessibleObject
*/

/*!
    Creates a QAccessibleWidget object for widget \a w.
    \a role and \a name are optional parameters that set the object's
    role and name properties.
*/
QAccessibleWidget::QAccessibleWidget(QWidget *w, Role role, const QString &name)
: QAccessibleObject(w)
{
    Q_ASSERT(widget());
    d = new QAccessibleWidgetPrivate();
    d->role = role;
    d->name = name;
    d->asking = 0;
}

/*!
    Destroys this object.
*/
QAccessibleWidget::~QAccessibleWidget()
{
    delete d;
}

/*!
    Returns the associated widget.
*/
QWidget *QAccessibleWidget::widget() const
{
    return qobject_cast<QWidget*>(object());
}

/*!
    Returns the associated widget's parent object, which is either the
    parent widget, or qApp for top-level widgets.
*/
QObject *QAccessibleWidget::parentObject() const
{
    QObject *parent = object()->parent();
    if (!parent)
        parent = qApp;
    return parent;
}

/*! \reimp */
int QAccessibleWidget::childAt(int x, int y) const
{
    QWidget *w = widget();
    QPoint gp = w->mapToGlobal(QPoint(0, 0));
    if (!QRect(gp.x(), gp.y(), w->width(), w->height()).contains(x, y))
        return -1;

    QWidgetList list = childWidgets(w);
    int ccount = childCount();

    // a complex child
    if (list.size() < ccount) {
        for (int i = 1; i <= ccount; ++i) {
            if (rect(i).contains(x, y))
                return i;
        }
        return 0;
    }

    QPoint rp = w->mapFromGlobal(QPoint(x, y));
    for (int i = 0; i<list.size(); ++i) {
        QWidget *child = list.at(i);
        if (!child->isWindow() && !child->isHidden() && child->geometry().contains(rp)) {
            return i + 1;
        }
    }
    return -1;
}

/*! \reimp */
QRect QAccessibleWidget::rect(int child) const
{
    if (child)
        qWarning("QAccessibleWidget::rect: This implementation does not support subelements! (ID %d unknown for %s)", child, widget()->metaObject()->className());

    QWidget *w = widget();
    QPoint wpos = w->mapToGlobal(QPoint(0, 0));

    return QRect(wpos.x(), wpos.y(), w->width(), w->height());
}

#include <private/qobject_p.h>

class ConnectionObject : public QObject
{
    Q_DECLARE_PRIVATE(QObject)
public:
    inline bool isSender(const QObject *receiver, const char *signal) const
    { return d_func()->isSender(receiver, signal); }
    inline QObjectList receiverList(const char *signal) const
    { return d_func()->receiverList(signal); }
    inline QObjectList senderList() const
    { return d_func()->senderList(); }
};

/*!
    Registers \a signal as a controlling signal.

    An object is a Controller to any other object connected to a
    controlling signal.
*/
void QAccessibleWidget::addControllingSignal(const QString &signal)
{
    QByteArray s = QMetaObject::normalizedSignature(signal.toAscii());
    if (object()->metaObject()->indexOfSignal(s) < 0)
        qWarning("Signal %s unknown in %s", (const char*)s, object()->metaObject()->className());
    d->primarySignals << s;
}

/*!
    Sets the value of this interface implementation to \a value.

    The default implementation of text() returns the set value for
    the Value text.

    Note that the object wrapped by this interface is not modified.
*/
void QAccessibleWidget::setValue(const QString &value)
{
    d->value = value;
}

/*!
    Sets the description of this interface implementation to \a desc.

    The default implementation of text() returns the set value for
    the Description text.

    Note that the object wrapped by this interface is not modified.
*/
void QAccessibleWidget::setDescription(const QString &desc)
{
    d->description = desc;
}

/*!
    Sets the help of this interface implementation to \a help.

    The default implementation of text() returns the set value for
    the Help text.

    Note that the object wrapped by this interface is not modified.
*/
void QAccessibleWidget::setHelp(const QString &help)
{
    d->help = help;
}

/*!
    Sets the accelerator of this interface implementation to \a accel.

    The default implementation of text() returns the set value for
    the Accelerator text.

    Note that the object wrapped by this interface is not modified.
*/
void QAccessibleWidget::setAccelerator(const QString &accel)
{
    d->accelerator = accel;
}

static inline bool isAncestor(const QObject *obj, const QObject *child)
{
    while (child) {
        if (child == obj)
            return true;
        child = child->parent();
    }
    return false;
}


/*! \reimp */
QAccessible::Relation QAccessibleWidget::relationTo(int child,
            const QAccessibleInterface *other, int otherChild) const
{
    Relation relation = Unrelated;
    if (d->asking == this) // recursive call
        return relation;

    QObject *o = other ? other->object() : 0;
    if (!o)
        return relation;

    QWidget *focus = widget()->focusWidget();
    if (object() == focus && isAncestor(o, focus))
        relation |= FocusChild;

    ConnectionObject *connectionObject = (ConnectionObject*)object();
    for (int sig = 0; sig < d->primarySignals.count(); ++sig) {
        if (connectionObject->isSender(o, d->primarySignals.at(sig).toAscii())) {
            relation |= Controller;
            break;
        }
    }
    // test for passive relationships.
    // d->asking protects from endless recursion.
    d->asking = this;
    int inverse = other->relationTo(otherChild, this, child);
    d->asking = 0;

    if (inverse & Controller)
        relation |= Controlled;
    if (inverse & Label)
        relation |= Labelled;

    if(o == object()) {
        if (child && !otherChild)
            return relation | Child;
        if (!child && otherChild)
            return relation | Ancestor;
        if (!child && !otherChild)
            return relation | Self;
    }

    QObject *parent = object()->parent();
    if (o == parent)
        return relation | Child;

    if (o->parent() == parent) {
        relation |= Sibling;
        QAccessibleInterface *sibIface = QAccessible::queryAccessibleInterface(o);
        Q_ASSERT(sibIface);
        QRect wg = rect(0);
        QRect sg = sibIface->rect(0);
        if (wg.intersects(sg)) {
            QAccessibleInterface *pIface = 0;
            sibIface->navigate(Ancestor, 1, &pIface);
            if (pIface && !((sibIface->state(0) | state(0)) & Invisible)) {
                int wi = pIface->indexOfChild(this);
                int si = pIface->indexOfChild(sibIface);

                if (wi > si)
                    relation |= QAccessible::Covers;
                else
                    relation |= QAccessible::Covered;
            }
            delete pIface;
        } else {
            QPoint wc = wg.center();
            QPoint sc = sg.center();
            if (wc.x() < sc.x())
                relation |= QAccessible::Left;
            else if(wc.x() > sc.x())
                relation |= QAccessible::Right;
            if (wc.y() < sc.y())
                relation |= QAccessible::Up;
            else if (wc.y() > sc.y())
                relation |= QAccessible::Down;
        }
        delete sibIface;

        return relation;
    }

    if (isAncestor(o, object()))
        return relation | Descendent;
    if (isAncestor(object(), o))
        return relation | Ancestor;

    return relation;
}

/*! \reimp */
int QAccessibleWidget::navigate(RelationFlag relation, int entry,
                                QAccessibleInterface **target) const
{
    if (!target)
        return -1;

    *target = 0;
    QObject *targetObject = 0;

    QWidgetList childList = childWidgets(widget());
    bool complexWidget = childList.size() < childCount();

    switch (relation) {
    // Hierarchical
    case Self:
        targetObject = object();
        break;
    case Child:
        if (complexWidget) {
            if (entry > 0 && entry <= childCount())
                return entry;
            return -1;
        }else {
            if (entry > 0 && childList.size() >= entry)
                targetObject = childList.at(entry - 1);
        }
        break;
    case Ancestor:
        {
            if (entry <= 0)
                return -1;
            targetObject = widget()->parentWidget();
            int i;
            for (i = entry; i > 1 && targetObject; --i)
                targetObject = targetObject->parent();
            if (!targetObject && i == 1)
                targetObject = qApp;
        }
        break;
    case Sibling:
        {
            QAccessibleInterface *iface = QAccessible::queryAccessibleInterface(parentObject());
            if (!iface)
                return -1;

            iface->navigate(Child, entry, target);
            delete iface;
            if (*target)
                return 0;
        }
        break;

    // Geometrical
    case QAccessible::Left:
        if (complexWidget && entry) {
            if (entry < 2 || widget()->height() > widget()->width() + 20) // looks vertical
                return -1;
            return entry - 1;
        }
        // fall through
    case QAccessible::Right:
        if (complexWidget && entry) {
            if (entry >= childCount() || widget()->height() > widget()->width() + 20) // looks vertical
                return -1;
            return entry + 1;
        }
        // fall through
    case QAccessible::Up:
        if (complexWidget && entry) {
            if (entry < 2 || widget()->width() > widget()->height() + 20) // looks horizontal
                return - 1;
            return entry - 1;
        }
        // fall through
    case QAccessible::Down:
        if (complexWidget && entry) {
            if (entry >= childCount() || widget()->width() > widget()->height()  + 20) // looks horizontal
                return - 1;
            return entry + 1;
        } else {
            QAccessibleInterface *pIface = QAccessible::queryAccessibleInterface(parentObject());
            if (!pIface)
                return -1;

            QRect startg = rect(0);
            QPoint startc = startg.center();
            QAccessibleInterface *candidate = 0;
            int mindist = 100000;
            int sibCount = pIface->childCount();
            for (int i = 0; i < sibCount; ++i) {
                QAccessibleInterface *sibling = 0;
                pIface->navigate(Child, i+1, &sibling);
                Q_ASSERT(sibling);
                if ((relationTo(0, sibling, 0) & Self) || (sibling->state(0) & QAccessible::Invisible)) {
                    //ignore ourself and invisible siblings
                    delete sibling;
                    continue;
                }

                QRect sibg = sibling->rect(0);
                QPoint sibc = sibg.center();
                QPoint sibp;
                QPoint startp;
                QPoint distp;
                switch (relation) {
                case QAccessible::Left:
                    startp = QPoint(startg.left(), startg.top() + startg.height() / 2);
                    sibp = QPoint(sibg.right(), sibg.top() + sibg.height() / 2);
                    if (QPoint(sibc - startc).x() >= 0) {
                        delete sibling;
                        continue;
                    }
                    distp = sibp - startp;
                    break;
                case QAccessible::Right:
                    startp = QPoint(startg.right(), startg.top() + startg.height() / 2);
                    sibp = QPoint(sibg.left(), sibg.top() + sibg.height() / 2);
                    if (QPoint(sibc - startc).x() <= 0) {
                        delete sibling;
                        continue;
                    }
                    distp = sibp - startp;
                    break;
                case QAccessible::Up:
                    startp = QPoint(startg.left() + startg.width() / 2, startg.top());
                    sibp = QPoint(sibg.left() + sibg.width() / 2, sibg.bottom());
                    if (QPoint(sibc - startc).y() >= 0) {
                        delete sibling;
                        continue;
                    }
                    distp = sibp - startp;
                    break;
                case QAccessible::Down:
                    startp = QPoint(startg.left() + startg.width() / 2, startg.bottom());
                    sibp = QPoint(sibg.left() + sibg.width() / 2, sibg.top());
                    if (QPoint(sibc - startc).y() <= 0) {
                        delete sibling;
                        continue;
                    }
                    distp = sibp - startp;
                    break;
		default:
		    break;
                }

                int dist = (int)sqrt((double)distp.x() * distp.x() + distp.y() * distp.y());
                if (dist < mindist) {
                    delete candidate;
                    candidate = sibling;
                    mindist = dist;
                } else {
                    delete sibling;
                }
            }
            delete pIface;
            *target = candidate;
            if (*target)
                return 0;
        }
        break;
    case Covers:
        if (entry > 0) {
            QAccessibleInterface *pIface = QAccessible::queryAccessibleInterface(parentObject());
            if (!pIface)
                return -1;

            QRect r = rect(0);
            int sibCount = pIface->childCount();
            QAccessibleInterface *sibling = 0;
            for (int i = pIface->indexOfChild(this) + 1; i <= sibCount && entry; ++i) {
                pIface->navigate(Child, i, &sibling);
                Q_ASSERT(sibling);
                if (!sibling || (sibling->state(0) & Invisible)) {
                    delete sibling;
                    sibling = 0;
                    continue;
                }
                if (sibling->rect(0).intersects(r))
                    --entry;
                if (!entry)
                    break;
                delete sibling;
                sibling = 0;
            }
            delete pIface;
            *target = sibling;
            if (*target)
                return 0;
        }
        break;
    case Covered:
        if (entry > 0) {
            QAccessibleInterface *pIface = QAccessible::queryAccessibleInterface(parentObject());
            if (!pIface)
                return -1;

            QRect r = rect(0);
            int index = pIface->indexOfChild(this);
            QAccessibleInterface *sibling = 0;
            for (int i = 1; i < index && entry; ++i) {
                pIface->navigate(Child, i, &sibling);
                Q_ASSERT(sibling);
                if (!sibling || (sibling->state(0) & Invisible)) {
                    delete sibling;
                    sibling = 0;
                    continue;
                }
                if (sibling->rect(0).intersects(r))
                    --entry;
                if (!entry)
                    break;
                delete sibling;
                sibling = 0;
            }
            delete pIface;
            *target = sibling;
            if (*target)
                return 0;
        }
        break;

    // Logical
    case FocusChild:
        {
            if (widget()->hasFocus())
                return 0;

            QWidget *fw = widget()->focusWidget();
            if (!fw)
                return -1;

            if (isAncestor(widget(), fw))
                targetObject = fw;
            /* ###
            QWidget *parent = fw;
            while (parent && !targetObject) {
                parent = parent->parentWidget();
                if (parent == widget())
                    targetObject = fw;
            }
            */
        }
        break;
    case Label:
        if (entry > 0) {
            QAccessibleInterface *pIface = QAccessible::queryAccessibleInterface(parentObject());
            if (!pIface)
                return -1;

            // first check for all siblings that are labels to us
            // ideally we would go through all objects and check, but that
            // will be too expensive
            int sibCount = pIface->childCount();
            QAccessibleInterface *candidate = 0;
            for (int i = 0; i < sibCount && entry; ++i) {
                pIface->navigate(Child, i+1, &candidate);
                Q_ASSERT(candidate);
                if (candidate->relationTo(0, this, 0) & Label)
                    --entry;
                if (!entry)
                    break;
                delete candidate;
                candidate = 0;
            }
            if (!candidate) {
                if (pIface->relationTo(0, this, 0) & Label)
                    --entry;
                if (!entry)
                    candidate = pIface;
            }
            if (pIface != candidate)
                delete pIface;

            *target = candidate;
            if (*target)
                return 0;
        }
        break;
    case Labelled: // only implemented in subclasses
        break;
    case Controller:
        if (entry > 0) {
            // check all senders we are connected to,
            // and figure out which one are controllers to us
            ConnectionObject *connectionObject = (ConnectionObject*)object();
            QObjectList allSenders = connectionObject->senderList();
            QObjectList senders;
            for (int s = 0; s < allSenders.size(); ++s) {
                QObject *sender = allSenders.at(s);
                QAccessibleInterface *candidate = QAccessible::queryAccessibleInterface(sender);
                if (!candidate)
                    continue;
                if (candidate->relationTo(0, this, 0)&Controller)
                    senders << sender;
                delete candidate;
            }
            if (entry <= senders.size())
                targetObject = senders.at(entry-1);
        }
        break;
    case Controlled:
        if (entry > 0) {
            QObjectList allReceivers;
            ConnectionObject *connectionObject = (ConnectionObject*)object();
            for (int sig = 0; sig < d->primarySignals.count(); ++sig) {
                QObjectList receivers = connectionObject->receiverList(d->primarySignals.at(sig).toAscii());
                allReceivers += receivers;
            }
            if (entry <= allReceivers.size())
                targetObject = allReceivers.at(entry-1);
        }
        break;
    default:
        break;
    }
    *target = QAccessible::queryAccessibleInterface(targetObject);
    return *target ? 0 : -1;
}

/*! \reimp */
int QAccessibleWidget::childCount() const
{
    QWidgetList cl = childWidgets(widget());
    return cl.size();
}

/*! \reimp */
int QAccessibleWidget::indexOfChild(const QAccessibleInterface *child) const
{
    QWidgetList cl = childWidgets(widget());
    int index = cl.indexOf(qobject_cast<QWidget *>(child->object()));
    if (index != -1)
        ++index;
    return index;
}

/*! \reimp */
QString QAccessibleWidget::text(Text t, int child) const
{
    QString str;

    switch (t) {
    case Name:
        if (!d->name.isEmpty())
            str = d->name;
        else if (!widget()->accessibleName().isEmpty())
            str = widget()->accessibleName();
        else if (!child && widget()->isWindow())
            str = widget()->windowTitle();
        else
            str = qt_accStripAmp(buddyString(widget()));
        break;
    case Description:
        if (!d->description.isEmpty())
            str = d->description;
        else if (!widget()->accessibleDescription().isEmpty())
            str = widget()->accessibleDescription();
#ifndef QT_NO_TOOLTIP
        else
            str = widget()->toolTip();
#endif
        break;
    case Help:
        if (!d->help.isEmpty())
            str = d->help;
        else
            str = widget()->whatsThis();
        break;
    case Accelerator:
        if (!d->accelerator.isEmpty())
            str = d->accelerator;
        else
            str = qt_accHotKey(buddyString(widget()));
        break;
    case Value:
        str = d->value;
        break;
    default:
        break;
    }
    return str;
}

/*! \reimp */
QString QAccessibleWidget::actionText(int action, Text t, int child) const
{
    if (action == DefaultAction)
        action = SetFocus;

    return QAccessibleObject::actionText(action, t, child);
}

/*! \reimp */
bool QAccessibleWidget::doAction(int action, int child, const QVariantList &params)
{
    if (action == SetFocus || action == DefaultAction) {
        if (child || !widget()->isEnabled())
            return false;
        if (widget()->focusPolicy() != Qt::NoFocus)
            widget()->setFocus();
        else if (widget()->isWindow())
            widget()->activateWindow();
        else
            return false;
        return true;
    }
    return QAccessibleObject::doAction(action, child, params);
}

/*! \reimp */
QAccessible::Role QAccessibleWidget::role(int child) const
{
    if (!child)
        return d->role;
    return NoRole;
}

/*! \reimp */
QAccessible::State QAccessibleWidget::state(int child) const
{
    if (child)
        return Normal;

    int state = Normal;

    QWidget *w = widget();
    if (w->testAttribute(Qt::WA_WState_Hidden))
        state |= Invisible;
    if (w->focusPolicy() != Qt::NoFocus && w->isActiveWindow())
        state |= Focusable;
    if (w->hasFocus())
        state |= Focused;
    if (!w->isEnabled())
        state |= Unavailable;
    if (w->isWindow()) {
        if (w->windowFlags() & Qt::WindowSystemMenuHint)
            state |= Movable;
        if (w->minimumSize() != w->maximumSize())
            state |= Sizeable;
    }

    return (State)state;
}

#endif //QT_NO_ACCESSIBILITY
