/*
    KStyle for KDE5 (KDE Integration)
        SPDX-FileCopyrightText: 2013 Alejandro Fiestas Olivares <afiestas@kde.org>

    KStyle for KDE4
        SPDX-FileCopyrightText: 2004-2005 Maksim Orlovich <maksim@kde.org>
        SPDX-FileCopyrightText: 2005, 2006 Sandro Giessl <giessl@kde.org>

    Based in part on the following software:

    KStyle for KDE3
        SPDX-FileCopyrightText: 2001-2002 Karol Szwed <gallium@kde.org>
    Portions
        SPDX-FileCopyrightText: 1998-2000 TrollTech AS

    Keramik for KDE3,
        SPDX-FileCopyrightText: 2002 Malte Starostik <malte@kde.org>
        SPDX-FileCopyrightText: 2002-2003 Maksim Orlovich  <maksim@kde.org>
    Portions
        SPDX-FileCopyrightText: 2001-2002 Karol Szwed <gallium@kde.org>
        SPDX-FileCopyrightText: 2001-2002 Fredrik Höglund <fredrik@kde.org>
        SPDX-FileCopyrightText: 2000 Daniel M. Duley <mosfet@kde.org>
        SPDX-FileCopyrightText: 2000 Dirk Mueller <mueller@kde.org>
        SPDX-FileCopyrightText: 2001 Martijn Klingens <klingens@kde.org>
        SPDX-FileCopyrightText: 2003 Sandro Giessl <sandro@giessl.com>

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

#ifndef KDE_KSTYLE_H
#define KDE_KSTYLE_H

#include <kstyle_export.h>

#include <QCommonStyle>
#include <QPalette>

class KStylePrivate;

/*!
 * \class KStyle
 * \inmodule KStyle
 *
 * \brief Provides integration with KDE Plasma Workspace settings for Qt styles.
 *
 * Derive your Qt style from KStyle to automatically inherit
 * various settings from the KDE Plasma Workspace, providing a
 * consistent user experience. For example, this will ensure a
 * consistent single-click or double-click activation setting,
 * and the use of standard themed icons.
 */
class KSTYLE_EXPORT KStyle : public QCommonStyle
{
    Q_OBJECT

public:
    KStyle();
    ~KStyle() override;

    /*!
     * Runtime element extension
     * This is just convenience and does /not/ require the using widgets style to inherit KStyle
     * (i.e. calling this while using cleanlooks won't segfault or so but just return 0)
     * Returns a unique id for an element string (e.g. "CE_CapacityBar")
     *
     * For simplicity, only StyleHints, ControlElements and their SubElements are supported
     * If you don't need extended SubElement functionality, just drop it
     *
     * \a element The style element, represented as string.
     * Naming convention: "appname.(2-char-element-type)_element"
     * where the 2-char-element-type is of {SH, CE, SE}
     * (widgets in kdelibs don't have to pass the appname)
     * examples: "CE_CapacityBar", "amarok.CE_Analyzer"
     *
     * \a widget Your widget ("this") passing this is mandatory, passing NULL will just return 0
     *
     * Returns a unique id for the \a element string or 0, if the element is not supported by the
     * widgets current style
     *
     * Important notes:
     *
     * 1) If your string lacks the matching "SH_", "CE_" or "SE_" token the element
     * request will be ignored (return is 0)
     *
     * 2) Try to avoid custom elements and use default ones (if possible) to get better style support
     * and keep UI coherency
     *
     * 3) If you cache this value (good idea, this requires a map lookup) don't (!) forget to catch
     * style changes in QWidget::changeEvent()
     */
    static StyleHint customStyleHint(const QString &element, const QWidget *widget);

    /*!
     *
     */
    static ControlElement customControlElement(const QString &element, const QWidget *widget);

    /*!
     *
     */
    static SubElement customSubElement(const QString &element, const QWidget *widget);

protected:
    /*!
     * Runtime element extension, allows inheriting styles to add support custom elements
     * merges supporting inherit chains
     * Supposed to be called e.g. in your constructor.
     *
     * NOTICE: in order to have this work, your style must provide
     * an "X-KDE-CustomElements" classinfo, i.e.
     * \code
     * class MyStyle : public KStyle
     * {
     *       Q_OBJECT
     *       Q_CLASSINFO ("X-KDE-CustomElements", "true")
     *
     *   public:
     *       .....
     * }
     * \endcode
     *
     * \a element The style element, represented as string.
     * Suggested naming convention: appname.(2-char-element-type)_element
     * where the 2-char-element-type is of {SH, CE, SE}
     * widgets in kdelibs don't have to pass the appname
     * examples: "CE_CapacityBar", "amarok.CE_Analyzer"
     *
     * Important notes:
     * 1) If your string lacks the matching "SH_", "CE_" or "SE_" token the element
     * request will be ignored (return is 0)
     * 2) To keep UI coherency, don't support any nonsense in your style, but convince app developers
     * to use standard elements - if available
     */
    StyleHint newStyleHint(const QString &element);

    /*!
     *
     */
    ControlElement newControlElement(const QString &element);

    /*!
     *
     */
    SubElement newSubElement(const QString &element);

public:
    int pixelMetric(PixelMetric m, const QStyleOption *opt = nullptr, const QWidget *widget = nullptr) const override;
    int styleHint(StyleHint hint, const QStyleOption *opt, const QWidget *w, QStyleHintReturn *returnData) const override;

    void polish(QWidget *) override;
    using QCommonStyle::polish; // needed to avoid warnings at compilation time

    QPalette standardPalette() const override;

    QIcon standardIcon(StandardPixmap standardIcon, const QStyleOption *option = nullptr, const QWidget *widget = nullptr) const override;

private:
    KStylePrivate *const d;
};

#endif // KDE_KSTYLE_H