// Copyright (C) 2023-2024 Stdware Collections (https://www.github.com/stdware)
// Copyright (C) 2021-2023 wangwenx190 (Yuhang Zhao)
// SPDX-License-Identifier: Apache-2.0

#include "widgetwindowagent.h"
#include "widgetwindowagent_p.h"

#include <QtGui/QtEvents>
#include <QtGui/QPainter>
#include <QtCore/QDebug>

#include "widgetitemdelegate_p.h"

namespace QWK {

    /*!
        \class WidgetWindowAgent
        \brief WindowAgentBase is the window agent for QtWidgets.

        It provides interfaces for QtWidgets and processes some Qt events related to the QWidget
        instance.
    */

    WidgetWindowAgentPrivate::WidgetWindowAgentPrivate() = default;

    WidgetWindowAgentPrivate::~WidgetWindowAgentPrivate() = default;

    void WidgetWindowAgentPrivate::init() {
    }

    /*!
        Constructs a widget agent, it's better to set the widget to setup as \a parent.
    */
    WidgetWindowAgent::WidgetWindowAgent(QObject *parent)
        : WidgetWindowAgent(*new WidgetWindowAgentPrivate(), parent) {
    }

    /*!
        Destructor.
    */
    WidgetWindowAgent::~WidgetWindowAgent() = default;

    /*!
        Installs the window agent on the widget. The window agent will take over some of the window
        events, making the window look frameless.
    */
    bool WidgetWindowAgent::setup(QWidget *w) {
        Q_ASSERT(w);
        if (!w) {
            return false;
        }

#if defined(_DEBUG) || !defined(NDEBUG)
        if (w->inherits("QDockWidget")) {
            qWarning()
                << "QWK::WidgetWindowAgent: QWindowKit does not support QDockWidget as top window.";
        }
#endif

        Q_D(WidgetWindowAgent);
        if (d->hostWidget) {
            return false;
        }

        // Qt will create invisible native window container for native QWidget
        // without this attribute, and this behavior will break QWK functionality.
        // So far enabling this attribute is a must for QWK users.
        w->setAttribute(Qt::WA_DontCreateNativeAncestors);
        // Make sure the native window handle is actually created before we apply
        // various hooks.
        // w->setAttribute(Qt::WA_NativeWindow); // ### FIXME: Check

        d->setup(w, new WidgetItemDelegate());
        d->hostWidget = w;

#if defined(Q_OS_WINDOWS) && QWINDOWKIT_CONFIG(ENABLE_WINDOWS_SYSTEM_BORDERS)
        d->setupWindows10BorderWorkaround();
#endif
        return true;
    }

    /*!
        Returns the title bar widget.
    */
    QWidget *WidgetWindowAgent::titleBar() const {
        Q_D(const WidgetWindowAgent);
        return static_cast<QWidget *>(d->context->titleBar());
    }

    /*!
        Sets the title bar widget, all system button and hit-test visible widget references that
        have been set will be removed.
    */
    void WidgetWindowAgent::setTitleBar(QWidget *w) {
        Q_D(WidgetWindowAgent);
        if (!d->context->setTitleBar(w)) {
            return;
        }
#ifdef Q_OS_MAC
        setSystemButtonArea(nullptr);
#endif
        Q_EMIT titleBarChanged(w);
    }

    /*!
        Returns the system button of the given type.
    */
    QWidget *WidgetWindowAgent::systemButton(SystemButton button) const {
        Q_D(const WidgetWindowAgent);
        return static_cast<QWidget *>(d->context->systemButton(button));
    }

    /*!
        Sets the system button of the given type, the system buttons always receive mouse events so
        you don't need to call \c setHitTestVisible for them.
    */
    void WidgetWindowAgent::setSystemButton(SystemButton button, QWidget *w) {
        Q_D(WidgetWindowAgent);
        if (!d->context->setSystemButton(button, w)) {
            return;
        }
        Q_EMIT systemButtonChanged(button, w);
    }

    /*!
        Returns \a true if the widget can receive mouse events on title bar.
    */
    bool WidgetWindowAgent::isHitTestVisible(const QWidget *w) const {
        Q_D(const WidgetWindowAgent);
        return d->context->isHitTestVisible(w);
    }

    /*!
        Makes the widget able to receive mouse events on title bar if \a visible is \c true.
        You're supposed to make sure that the specified widget \a w is a child or descendant
        of the title bar widget.
    */
    void WidgetWindowAgent::setHitTestVisible(QWidget *w, bool visible) {
        Q_D(WidgetWindowAgent);
        d->context->setHitTestVisible(w, visible);
    }

    /*!
        \internal
    */
    WidgetWindowAgent::WidgetWindowAgent(WidgetWindowAgentPrivate &d, QObject *parent)
        : WindowAgentBase(d, parent) {
        d.init();
    }

    /*!
        \fn void WidgetWindowAgent::titleBarChanged(const QWidget *w)

        This signal is emitted when the title bar widget is replaced.
    */

    /*!
        \fn void WidgetWindowAgent::systemButtonChanged(SystemButton button, const QWidget *w)

        This signal is emitted when a system button is replaced.
    */

}
