/***************************************************************************
 *   Copyright (C) 2011 by Peter Penz <peter.penz19@gmail.com>             *
 *                                                                         *
 *   Based on the Itemviews NG project from Trolltech Labs:                *
 *   http://qt.gitorious.org/qt-labs/itemviews-ng                          *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, 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 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            *
 ***************************************************************************/

#ifndef KITEMLISTWIDGET_H
#define KITEMLISTWIDGET_H

#include <libdolphin_export.h>

#include <kitemviews/kitemliststyleoption.h>

#include <QBitArray>
#include <QGraphicsWidget>
#include <QStyle>

class KItemListSelectionToggle;
class KItemListView;
class QPropertyAnimation;

/**
 * @brief Provides information for creating an instance of KItemListWidget.
 *
 * KItemListView only creates KItemListWidget instances for the visible
 * area. For calculating the required size of all items the expected
 * size for the invisible items must be accessible. KItemListWidgetInformant
 * provides this information.
 */
class LIBDOLPHINPRIVATE_EXPORT KItemListWidgetInformant
{
public:
    KItemListWidgetInformant();
    virtual ~KItemListWidgetInformant();

    virtual QSizeF itemSizeHint(int index, const KItemListView* view) const = 0;

    virtual qreal preferredRoleColumnWidth(const QByteArray& role,
                                           int index,
                                           const KItemListView* view) const = 0;
};

/**
 * @brief Widget that shows a visible item from the model.
 *
 * For showing an item from a custom model it is required to at least overwrite KItemListWidget::paint().
 * All properties are set by KItemListView, for each property there is a corresponding
 * virtual protected method that allows to react on property changes.
 */
class LIBDOLPHINPRIVATE_EXPORT KItemListWidget : public QGraphicsWidget
{
    Q_OBJECT

public:
    KItemListWidget(KItemListWidgetInformant* informant, QGraphicsItem* parent);
    virtual ~KItemListWidget();

    void setIndex(int index);
    int index() const;

    void setData(const QHash<QByteArray, QVariant>& data, const QSet<QByteArray>& roles = QSet<QByteArray>());
    QHash<QByteArray, QVariant> data() const;

    /**
     * Draws the hover-rectangle if the item is hovered. Overwrite this method
     * to show the data of the custom model provided by KItemListWidget::data().
     * @reimp
     */
    virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0);

    void setVisibleRoles(const QList<QByteArray>& roles);
    QList<QByteArray> visibleRoles() const;

    /**
     * Sets the width of a role that should be used if the alignment of the content
     * should be done in columns.
     */
    void setColumnWidth(const QByteArray& role, qreal width);
    qreal columnWidth(const QByteArray& role) const;

    void setStyleOption(const KItemListStyleOption& option);
    const KItemListStyleOption& styleOption() const;

    // TODO: Hides QGraphicsItem::setSelected()/isSelected(). Replace
    // this by using the default mechanism.
    void setSelected(bool selected);
    bool isSelected() const;

    void setCurrent(bool current);
    bool isCurrent() const;

    void setHovered(bool hovered);
    bool isHovered() const;

    void setAlternateBackground(bool enable);
    bool alternateBackground() const;

    void setEnabledSelectionToggle(bool enabled);
    bool enabledSelectionToggle() const;

    /**
     * Sets the sibling information for the item and all of its parents.
     * The sibling information of the upper most parent is represented by
     * the first bit, the sibling information of the item by the last bit.
     * The sibling information is useful for drawing the branches in
     * tree views.
     */
    void setSiblingsInformation(const QBitArray& siblings);
    QBitArray siblingsInformation() const;

    /**
     * Allows the user to edit the role \a role. The signals
     * roleEditingCanceled() or roleEditingFinished() will be
     * emitted after editing. An ongoing editing gets canceled if
     * the role is empty. Derived classes must implement
     * editedRoleChanged().
     */
    void setEditedRole(const QByteArray& role);
    QByteArray editedRole() const;

    /**
     * @return True if \a point is inside KItemListWidget::hoverRect(),
     *         KItemListWidget::textRect(), KItemListWidget::selectionToggleRect()
     *         or KItemListWidget::expansionToggleRect().
     * @reimp
     */
    virtual bool contains(const QPointF& point) const;

    /**
     * @return Rectangle for the area that shows the icon.
     */
    virtual QRectF iconRect() const = 0;

    /**
     * @return Rectangle for the area that contains the text-properties.
     */
    virtual QRectF textRect() const = 0;

    /**
     * @return Focus rectangle for indicating the current item. Per default
     *         textRect() will be returned. Overwrite this method if textRect()
     *         provides a larger rectangle than the actual text (e.g. to
     *         be aligned with the iconRect()). The textFocusRect() may not be
     *         outside the boundaries of textRect().
     */
    virtual QRectF textFocusRect() const;

    /**
     * @return Rectangle for the selection-toggle that is used to select or deselect an item.
     *         Per default an empty rectangle is returned which means that no selection-toggle
     *         is available.
     */
    virtual QRectF selectionToggleRect() const;

    /**
     * @return Rectangle for the expansion-toggle that is used to open a sub-tree of the model.
     *         Per default an empty rectangle is returned which means that no opening of sub-trees
     *         is supported.
     */
    virtual QRectF expansionToggleRect() const;

    /**
     * @return Pixmap that is used when dragging an item. Per default the current state of the
     *         widget is returned as pixmap.
     */
    virtual QPixmap createDragPixmap(const QStyleOptionGraphicsItem* option, QWidget* widget = 0);

signals:
    void roleEditingCanceled(int index, const QByteArray& role, const QVariant& value);
    void roleEditingFinished(int index, const QByteArray& role, const QVariant& value);

protected:
    virtual void dataChanged(const QHash<QByteArray, QVariant>& current, const QSet<QByteArray>& roles = QSet<QByteArray>());
    virtual void visibleRolesChanged(const QList<QByteArray>& current, const QList<QByteArray>& previous);
    virtual void columnWidthChanged(const QByteArray& role, qreal current, qreal previous);
    virtual void styleOptionChanged(const KItemListStyleOption& current, const KItemListStyleOption& previous);
    virtual void currentChanged(bool current);
    virtual void selectedChanged(bool selected);
    virtual void hoveredChanged(bool hovered);
    virtual void alternateBackgroundChanged(bool enabled);
    virtual void siblingsInformationChanged(const QBitArray& current, const QBitArray& previous);
    virtual void editedRoleChanged(const QByteArray& current, const QByteArray& previous);
    virtual void resizeEvent(QGraphicsSceneResizeEvent* event);

    /**
     * @return The current opacity of the hover-animation. When implementing a custom painting-code for a hover-state
     *         this opacity value should be respected.
     */
    qreal hoverOpacity() const;

    const KItemListWidgetInformant* informant() const;

private slots:
    void slotHoverAnimationFinished();

private:
    void initializeSelectionToggle();
    void setHoverOpacity(qreal opacity);
    void clearHoverCache();
    void drawItemStyleOption(QPainter* painter, QWidget* widget, QStyle::State styleState);

private:
    Q_PROPERTY(qreal hoverOpacity READ hoverOpacity WRITE setHoverOpacity)

    KItemListWidgetInformant* m_informant;
    int m_index;
    bool m_selected;
    bool m_current;
    bool m_hovered;
    bool m_alternateBackground;
    bool m_enabledSelectionToggle;
    QHash<QByteArray, QVariant> m_data;
    QList<QByteArray> m_visibleRoles;
    QHash<QByteArray, qreal> m_columnWidths;
    KItemListStyleOption m_styleOption;
    QBitArray m_siblingsInfo;

    qreal m_hoverOpacity;
    mutable QPixmap* m_hoverCache;
    QPropertyAnimation* m_hoverAnimation;

    KItemListSelectionToggle* m_selectionToggle;

    QByteArray m_editedRole;
};

inline const KItemListWidgetInformant* KItemListWidget::informant() const
{
    return m_informant;
}

#endif


