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#include "qabstractitemdelegate.h"

#ifndef QT_NO_ITEMVIEWS

#include <qabstractitemmodel.h>

#include <qabstractitemview.h>

#include <qfontmetrics.h>

#include <qwhatsthis.h>

#include <qtooltip.h>

#include <qevent.h>

#include <qstring.h>

#include <qdebug.h>

#include <private/qtextengine_p.h>

QT_BEGIN_NAMESPACE

/*!

    \class QAbstractItemDelegate

    \brief The QAbstractItemDelegate class is used to display and edit

    data items from a model.

    \ingroup model-view

    A QAbstractItemDelegate provides the interface and common functionality

    for delegates in the model/view architecture. Delegates display

    individual items in views, and handle the editing of model data.

    The QAbstractItemDelegate class is one of the \l{Model/View Classes}

    and is part of Qt's \l{Model/View Programming}{model/view framework}.

    To render an item in a custom way, you must implement paint() and

    sizeHint(). The QItemDelegate class provides default implementations for

    these functions; if you do not need custom rendering, subclass that

    class instead.

    We give an example of drawing a progress bar in items; in our case

    for a package management program.

    \image widgetdelegate.png

    We create the \c WidgetDelegate class, which inherits from

    QStyledItemDelegate. We do the drawing in the paint() function:

    \snippet doc/src/snippets/widgetdelegate.cpp 0

    Notice that we use a QStyleOptionProgressBar and initialize its

    members. We can then use the current QStyle to draw it.

    To provide custom editing, there are two approaches that can be

    used. The first approach is to create an editor widget and display

    it directly on top of the item. To do this you must reimplement

    createEditor() to provide an editor widget, setEditorData() to populate

    the editor with the data from the model, and setModelData() so that the

    delegate can update the model with data from the editor.

    The second approach is to handle user events directly by reimplementing

    editorEvent().

    \sa {model-view-programming}{Model/View Programming}, QItemDelegate,

        {Pixelator Example}, QStyledItemDelegate, QStyle

*/

/*!

    \enum QAbstractItemDelegate::EndEditHint

    This enum describes the different hints that the delegate can give to the

    model and view components to make editing data in a model a comfortable

    experience for the user.

    \value NoHint           There is no recommended action to be performed.

    These hints let the delegate influence the behavior of the view:

    \value EditNextItem     The view should use the delegate to open an

                            editor on the next item in the view.

    \value EditPreviousItem The view should use the delegate to open an

                            editor on the previous item in the view.

    Note that custom views may interpret the concepts of next and previous

    differently.

    The following hints are most useful when models are used that cache

    data, such as those that manipulate data locally in order to increase

    performance or conserve network bandwidth.

    \value SubmitModelCache If the model caches data, it should write out

                            cached data to the underlying data store.

    \value RevertModelCache If the model caches data, it should discard

                            cached data and replace it with data from the

                            underlying data store.

    Although models and views should respond to these hints in appropriate

    ways, custom components may ignore any or all of them if they are not

    relevant.

*/

/*!

  \fn void QAbstractItemDelegate::commitData(QWidget *editor)

  This signal must be emitted when the \a editor widget has completed

  editing the data, and wants to write it back into the model.

*/

/*!

    \fn void QAbstractItemDelegate::closeEditor(QWidget *editor, QAbstractItemDelegate::EndEditHint hint)

    This signal is emitted when the user has finished editing an item using

    the specified \a editor.

    The \a hint provides a way for the delegate to influence how the model and

    view behave after editing is completed. It indicates to these components

    what action should be performed next to provide a comfortable editing

    experience for the user. For example, if \c EditNextItem is specified,

    the view should use a delegate to open an editor on the next item in the

    model.

    \sa EndEditHint

*/

/*!

    \fn void QAbstractItemDelegate::sizeHintChanged(const QModelIndex &index)

    \since 4.4

    This signal must be emitted when the sizeHint() of \a index changed.

    Views automatically connect to this signal and relayout items as necessary.

*/

/*!

    Creates a new abstract item delegate with the given \a parent.

*/

QAbstractItemDelegate::QAbstractItemDelegate(QObject *parent)

    : QObject(parent)

{

}

/*!

    \internal

    Creates a new abstract item delegate with the given \a parent.

*/

QAbstractItemDelegate::QAbstractItemDelegate(QObjectPrivate &dd, QObject *parent)

    : QObject(dd, parent)

{

}

/*!

    Destroys the abstract item delegate.

*/

QAbstractItemDelegate::~QAbstractItemDelegate()

{

}

/*!

    \fn void QAbstractItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const = 0;

    This pure abstract function must be reimplemented if you want to

    provide custom rendering. Use the \a painter and style \a option to

    render the item specified by the item \a index.

    If you reimplement this you must also reimplement sizeHint().

*/

/*!

    \fn QSize QAbstractItemDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const = 0

    This pure abstract function must be reimplemented if you want to

    provide custom rendering. The options are specified by \a option

    and the model item by \a index.

    If you reimplement this you must also reimplement paint().

*/

/*!

    Returns the editor to be used for editing the data item with the

    given \a index. Note that the index contains information about the

    model being used. The editor's parent widget is specified by \a parent,

    and the item options by \a option.

    The base implementation returns 0. If you want custom editing you

    will need to reimplement this function.

    The returned editor widget should have Qt::StrongFocus;

    otherwise, \l{QMouseEvent}s received by the widget will propagate

    to the view. The view's background will shine through unless the

    editor paints its own background (e.g., with

    \l{QWidget::}{setAutoFillBackground()}).

    \sa setModelData() setEditorData()

*/

QWidget *QAbstractItemDelegate::createEditor(QWidget *,

                                             const QStyleOptionViewItem &,

                                             const QModelIndex &) const

{

    return 0;

}

/*!

    Sets the contents of the given \a editor to the data for the item

    at the given \a index. Note that the index contains information

    about the model being used.

    The base implementation does nothing. If you want custom editing

    you will need to reimplement this function.

    \sa setModelData()

*/

void QAbstractItemDelegate::setEditorData(QWidget *,

                                          const QModelIndex &) const

{

    // do nothing

}

/*!

    Sets the data for the item at the given \a index in the \a model

    to the contents of the given \a editor.

    The base implementation does nothing. If you want custom editing

    you will need to reimplement this function.

    \sa setEditorData()

*/

void QAbstractItemDelegate::setModelData(QWidget *,

                                         QAbstractItemModel *,

                                         const QModelIndex &) const

{

    // do nothing

}

/*!

    Updates the geometry of the \a editor for the item with the given

    \a index, according to the rectangle specified in the \a option.

    If the item has an internal layout, the editor will be laid out

    accordingly. Note that the index contains information about the

    model being used.

    The base implementation does nothing. If you want custom editing

    you must reimplement this function.

*/

void QAbstractItemDelegate::updateEditorGeometry(QWidget *,

                                                 const QStyleOptionViewItem &,

                                                 const QModelIndex &) const

{

    // do nothing

}

/*!

    Whenever an event occurs, this function is called with the \a event

    \a model \a option and the \a index that corresponds to the item being edited.

    The base implementation returns false (indicating that it has not

    handled the event).

*/

bool QAbstractItemDelegate::editorEvent(QEvent *,

                                        QAbstractItemModel *,

                                        const QStyleOptionViewItem &,

                                        const QModelIndex &)

{

    // do nothing

    return false;

}

/*!

    \obsolete

    Use QFontMetrics::elidedText() instead.

    \oldcode

        QFontMetrics fm = ...

        QString str = QAbstractItemDelegate::elidedText(fm, width, mode, text);

    \newcode

        QFontMetrics fm = ...

        QString str = fm.elidedText(text, mode, width);

    \endcode

*/

QString QAbstractItemDelegate::elidedText(const QFontMetrics &fontMetrics, int width,

                                          Qt::TextElideMode mode, const QString &text)

{

    return fontMetrics.elidedText(text, mode, width);

}

/*!

    \since 4.3

    Whenever a help event occurs, this function is called with the \a event

    \a view \a option and the \a index that corresponds to the item where the

    event occurs.

    Returns true if the delegate can handle the event; otherwise returns false.

    A return value of true indicates that the data obtained using the index had

    the required role.

    For QEvent::ToolTip and QEvent::WhatsThis events that were handled successfully,

    the relevant popup may be shown depending on the user's system configuration.

    \sa QHelpEvent

*/

// ### Qt 5: Make this a virtual non-slot function

bool QAbstractItemDelegate::helpEvent(QHelpEvent *event,

                                      QAbstractItemView *view,

                                      const QStyleOptionViewItem &option,

                                      const QModelIndex &index)

{

    Q_UNUSED(option);

    if (!event || !view)

        return false;

    switch (event->type()) {

#ifndef QT_NO_TOOLTIP

    case QEvent::ToolTip: {

        QHelpEvent *he = static_cast<QHelpEvent*>(event);

        QVariant tooltip = index.data(Qt::ToolTipRole);

        if (qVariantCanConvert<QString>(tooltip)) {

            QToolTip::showText(he->globalPos(), tooltip.toString(), view);

            return true;

        }

        break;}

#endif

#ifndef QT_NO_WHATSTHIS

    case QEvent::QueryWhatsThis: {

        if (index.data(Qt::WhatsThisRole).isValid())

            return true;

        break; }

    case QEvent::WhatsThis: {

        QHelpEvent *he = static_cast<QHelpEvent*>(event);

        QVariant whatsthis = index.data(Qt::WhatsThisRole);

        if (qVariantCanConvert<QString>(whatsthis)) {

            QWhatsThis::showText(he->globalPos(), whatsthis.toString(), view);

            return true;

        }

        break ; }

#endif

    default:

        break;

    }

    return false;

}

QT_END_NAMESPACE

#endif // QT_NO_ITEMVIEWS