/*
    This file is part of the KDE project
    SPDX-FileCopyrightText: 2006-2007, 2008 Fredrik Höglund <fredrik@kde.org>

    SPDX-License-Identifier: LGPL-2.0-or-later
*/

#ifndef KFILEITEMDELEGATE_H
#define KFILEITEMDELEGATE_H

#include "kiowidgets_export.h"
#include <QAbstractItemDelegate>
#include <QTextOption>

#include <memory>

class QAbstractItemModel;
class QAbstractItemView;
class QHelpEvent;
class QModelIndex;
class QPainter;

/**
 * @class KFileItemDelegate kfileitemdelegate.h <KFileItemDelegate>
 *
 * KFileItemDelegate is intended to be used to provide a KDE file system
 * view, when using one of the standard item views in Qt with KDirModel.
 *
 * While primarily intended to be used with KDirModel, it uses
 * Qt::DecorationRole and Qt::DisplayRole for the icons and text labels,
 * just like QItemDelegate, and can thus be used with any standard model.
 *
 * When used with KDirModel however, KFileItemDelegate can change the way
 * the display and/or decoration roles are drawn, based on properties
 * of the file items. For example, if the file item is a symbolic link,
 * it will use an italic font to draw the file name.
 *
 * KFileItemDelegate also supports showing additional information about
 * the file items below the icon labels.
 *
 * Which information should be shown, if any, is controlled by the
 * @ref information property, which is a list that can be set by calling
 * setShowInformation(), and read by calling showInformation().
 * By default this list is empty.
 *
 * To use KFileItemDelegate, instantiate an object from the delegate,
 * and call setItemDelegate() in one of the standard item views in Qt:
 *
 * @code
 * QListView *listview = new QListView(this);
 * KFileItemDelegate *delegate = new KFileItemDelegate(this);
 * listview->setItemDelegate(delegate);
 * @endcode
 */
class KIOWIDGETS_EXPORT KFileItemDelegate : public QAbstractItemDelegate
{
    Q_OBJECT

    /**
     * This property holds which additional information (if any) should be shown below
     * items in icon views.
     *
     * Access functions:
     * @li void setShownformation(InformationList information)
     * @li InformationList showInformation() const
     */
    Q_PROPERTY(InformationList information READ showInformation WRITE setShowInformation)

    /**
     * This property holds the color used for the text shadow.
     *
     * The alpha value in the color determines the opacity of the shadow.
     * Shadows are only rendered when the alpha value is non-zero.
     * The default value for this property is Qt::transparent.
     *
     * Access functions:
     * @li void setShadowColor(const QColor &color)
     * @li QColor shadowColor() const
     */
    Q_PROPERTY(QColor shadowColor READ shadowColor WRITE setShadowColor)

    /**
     * This property holds the horizontal and vertical offset for the text shadow.
     * The default value for this property is (1, 1).
     *
     * Access functions:
     * @li void setShadowOffset(const QPointF &offset)
     * @li QPointF shadowOffset() const
     */
    Q_PROPERTY(QPointF shadowOffset READ shadowOffset WRITE setShadowOffset)

    /**
     * This property holds the blur radius for the text shadow.
     * The default value for this property is 2.
     *
     * Access functions:
     * @li void setShadowBlur(qreal radius)
     * @li qreal shadowBlur() const
     */
    Q_PROPERTY(qreal shadowBlur READ shadowBlur WRITE setShadowBlur)

    /**
     * This property holds the maximum size that can be returned
     * by KFileItemDelegate::sizeHint(). If the maximum size is empty,
     * it will be ignored.
     */
    Q_PROPERTY(QSize maximumSize READ maximumSize WRITE setMaximumSize)

    /**
     * This property determines whether a tooltip will be shown by the delegate
     * if the display role is elided. This tooltip will contain the full display
     * role information. The tooltip will only be shown if the Qt::ToolTipRole differs
     * from Qt::DisplayRole, or if they match, showToolTipWhenElided flag is set and
     * the display role information is elided.
     */
    Q_PROPERTY(bool showToolTipWhenElided READ showToolTipWhenElided WRITE setShowToolTipWhenElided)

    /**
     * This property determines if there are KIO jobs on a destination URL visible, then
     * they will have a small animation overlay displayed on them.
     */
    Q_PROPERTY(bool jobTransfersVisible READ jobTransfersVisible WRITE setJobTransfersVisible)

public:
    /**
     * This enum defines the additional information that can be displayed below item
     * labels in icon views.
     *
     * The information will only be shown for indexes for which the model provides
     * a valid value for KDirModel::FileItemRole, and only when there's sufficient vertical
     * space to display at least one line of the information, along with the display label.
     *
     * For the number of items to be shown for folders, the model must provide a valid
     * value for KDirMode::ChildCountRole, in addition to KDirModel::FileItemRole.
     *
     * Note that KFileItemDelegate will not call KFileItem::determineMimeType() if
     * KFileItem::isMimeTypeKnown() returns false, so if you want to display MIME types
     * you should use a KMimeTypeResolver with the model and the view, to ensure that MIME
     * types are resolved. If the MIME type isn't known, "Unknown" will be displayed until
     * the MIME type has been successfully resolved.
     *
     * @see setShowInformation()
     * @see showInformation()
     * @see information
     */
    enum Information {
        NoInformation, ///< No additional information will be shown for items.
        Size, ///< The file size for files, and the number of items for folders.
        Permissions, ///< A UNIX permissions string, e.g.\ -rwxr-xr-x.
        OctalPermissions, ///< The permissions as an octal value, e.g.\ 0644.
        Owner, ///< The user name of the file owner, e.g.\ root
        OwnerAndGroup, ///< The user and group that owns the file, e.g.\ root:root
        CreationTime, ///< The date and time the file/folder was created.
        ModificationTime, ///< The date and time the file/folder was last modified.
        AccessTime, ///< The date and time the file/folder was last accessed.
        MimeType, ///< The MIME type for the item, e.g.\ text/html.
        FriendlyMimeType, ///< The descriptive name for the MIME type, e.g.\ HTML Document.
        LinkDest, ///< The destination of a symbolic link. @since 4.5
        LocalPathOrUrl, ///< The local path to the file or the URL in case it is not a local file. @since 4.5
        Comment, ///< A simple comment that can be displayed to the user as is. @since 4.6
    };
    Q_ENUM(Information)

    typedef QList<Information> InformationList;

    /**
     * Constructs a new KFileItemDelegate.
     *
     * @param parent The parent object for the delegate.
     */
    explicit KFileItemDelegate(QObject *parent = nullptr);

    /**
     * Destroys the item delegate.
     */
    ~KFileItemDelegate() override;

    /**
     * Returns the nominal size for the item referred to by @p index, given the
     * provided options.
     *
     * If the model provides a valid Qt::FontRole and/or Qt::TextAlignmentRole for the item,
     * those will be used instead of the ones specified in the style options.
     *
     * This function is reimplemented from @ref QAbstractItemDelegate.
     *
     * @param option  The style options that should be used when painting the item.
     * @param index   The index to the item for which to return the size hint.
     */
    QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const override;

    /**
     * Paints the item indicated by @p index, using @p painter.
     *
     * The item will be drawn in the rectangle specified by option.rect.
     * The correct size for that rectangle can be obtained by calling
     * @ref sizeHint().
     *
     * This function will use the following data values if the model provides
     * them for the item, in place of the values in @p option:
     *
     * @li Qt::FontRole           The font that should be used for the display role.
     * @li Qt::TextAlignmentRole  The alignment of the display role.
     * @li Qt::ForegroundRole     The text color for the display role.
     * @li Qt::BackgroundRole     The background color for the item.
     *
     * This function is reimplemented from @ref QAbstractItemDelegate.
     *
     * @param painter The painter with which to draw the item.
     * @param option  The style options that should be used when painting the item.
     * @param index   The index to the item that should be painted.
     */
    void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const override;

    /**
     * Reimplemented from @ref QAbstractItemDelegate.
     */
    QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const override;

    /**
     * Reimplemented from @ref QAbstractItemDelegate.
     */
    bool editorEvent(QEvent *event, QAbstractItemModel *model, const QStyleOptionViewItem &option, const QModelIndex &index) override;

    /**
     * Reimplemented from @ref QAbstractItemDelegate.
     */
    void setEditorData(QWidget *editor, const QModelIndex &index) const override;

    /**
     * Reimplemented from @ref QAbstractItemDelegate.
     */
    void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const override;

    /**
     * Reimplemented from @ref QAbstractItemDelegate.
     */
    void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const override;

    /**
     * Sets the list of information lines that are shown below the icon label in list views.
     *
     * You will typically construct the list like this:
     * @code
     * KFileItemDelegate::InformationList list;
     * list << KFileItemDelegate::FriendlyMimeType << KFileItemDelegate::Size;
     * delegate->setShowInformation(list);
     * @endcode
     *
     * The information lines will be displayed in the list order.
     * The delegate will first draw the item label, and then as many information
     * lines as will fit in the available space.
     *
     * @param list A list of information items that should be shown
     */
    void setShowInformation(const InformationList &list);

    /**
     * Sets a single information line that is shown below the icon label in list views.
     *
     * This is a convenience function for when you only want to show a single line
     * of information.
     *
     * @param information The information that should be shown
     */
    void setShowInformation(Information information);

    /**
     * Returns the file item information that should be shown below item labels in list views.
     */
    InformationList showInformation() const;

    /**
     * Sets the color used for drawing the text shadow.
     *
     * To enable text shadows, set the shadow color to a non-transparent color.
     * To disable text shadows, set the color to Qt::transparent.
     *
     * @see shadowColor()
     */
    void setShadowColor(const QColor &color);

    /**
     * Returns the color used for the text shadow.
     *
     * @see setShadowColor()
     */
    QColor shadowColor() const;

    /**
     * Sets the horizontal and vertical offset for the text shadow.
     *
     * @see shadowOffset()
     */
    void setShadowOffset(const QPointF &offset);

    /**
     * Returns the offset used for the text shadow.
     *
     * @see setShadowOffset()
     */
    QPointF shadowOffset() const;

    /**
     * Sets the blur radius for the text shadow.
     *
     * @see shadowBlur()
     */
    void setShadowBlur(qreal radius);

    /**
     * Returns the blur radius for the text shadow.
     *
     * @see setShadowBlur()
     */
    qreal shadowBlur() const;

    /**
     * Sets the maximum size for KFileItemDelegate::sizeHint().
     *
     * @see maximumSize()
     */
    void setMaximumSize(const QSize &size);

    /**
     * Returns the maximum size for KFileItemDelegate::sizeHint().
     *
     * @see setMaximumSize()
     */
    QSize maximumSize() const;

    /**
     * Sets whether a tooltip should be shown if the display role is
     * elided containing the full display role information.
     *
     * @note The tooltip will only be shown if the Qt::ToolTipRole differs
     *       from Qt::DisplayRole, or if they match, showToolTipWhenElided
     *       flag is set and the display role information is elided.
     * @see showToolTipWhenElided()
     */
    void setShowToolTipWhenElided(bool showToolTip);

    /**
     * Returns whether a tooltip should be shown if the display role
     * is elided containing the full display role information.
     *
     * @note The tooltip will only be shown if the Qt::ToolTipRole differs
     *       from Qt::DisplayRole, or if they match, showToolTipWhenElided
     *       flag is set and the display role information is elided.
     * @see setShowToolTipWhenElided()
     */
    bool showToolTipWhenElided() const;

    /**
     * Returns the rectangle of the icon that is aligned inside the decoration
     * rectangle.
     */
    QRect iconRect(const QStyleOptionViewItem &option, const QModelIndex &index) const;

    /**
     * When the contents text needs to be wrapped, @p wrapMode strategy
     * will be followed.
     *
     */
    void setWrapMode(QTextOption::WrapMode wrapMode);

    /**
     * Returns the wrapping strategy followed to show text when it needs
     * wrapping.
     *
     */
    QTextOption::WrapMode wrapMode() const;

    /**
     * Enable/Disable the displaying of an animated overlay that is shown for any destination
     * urls (in the view). When enabled, the animations (if any) will be drawn automatically.
     *
     * Only the files/folders that are visible and have jobs associated with them
     * will display the animation.
     * You would likely not want this enabled if you perform some kind of custom painting
     * that takes up a whole item, and will just make this(and what you paint) look funky.
     *
     * Default is disabled.
     *
     * Note: The model (KDirModel) needs to have it's method called with the same
     * value, when you make the call to this method.
     */
    void setJobTransfersVisible(bool jobTransfersVisible);

    /**
     * Returns whether or not the displaying of job transfers is enabled.
     * @see setJobTransfersVisible()
     */
    bool jobTransfersVisible() const;

    /**
     * Reimplemented from @ref QAbstractItemDelegate.
     */
    bool eventFilter(QObject *object, QEvent *event) override;

public Q_SLOTS:
    /**
     * Reimplemented from @ref QAbstractItemDelegate.
     */
    bool helpEvent(QHelpEvent *event, QAbstractItemView *view, const QStyleOptionViewItem &option, const QModelIndex &index) override;

    /**
     * Returns the shape of the item as a region.
     * The returned region can be used for precise hit testing of the item.
     */
    QRegion shape(const QStyleOptionViewItem &option, const QModelIndex &index);

private:
    class Private;
    std::unique_ptr<Private> const d; /// @internal
    Q_DISABLE_COPY(KFileItemDelegate)
};

#endif // KFILEITEMDELEGATE_H