// Copyright (C) 2019 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only

#ifndef QSSGOBJECT_P_H
#define QSSGOBJECT_P_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include "qquick3dobject.h"

#include "qtquick3dglobal_p.h"

#include "qquick3dobjectchangelistener_p.h"

#include "qquick3dscenemanager_p.h"

#include <private/qobject_p.h>
#include <private/qquickstate_p.h>
#include <private/qqmlnotifier_p.h>
#include <private/qlazilyallocated_p.h>
#include <private/qssgrendergraphobject_p.h>
#include <QtQuick3DUtils/private/qquick3dprofiler_p.h>

#include <QtCore/qpointer.h>

QT_BEGIN_NAMESPACE

class QQuick3DItem2D;

class Q_QUICK3D_EXPORT QQuick3DObjectPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QQuick3DObject)
public:
    using Type = QSSGRenderGraphObject::Type;

    struct ConnectionKey
    {
        using Handle = void (QQuick3DObject::*)(QObject *);
        QObject *context = nullptr;
        Handle unusable = nullptr;
        friend bool operator==(const ConnectionKey &a, const ConnectionKey &b) noexcept { return (a.context == b.context) && (a.unusable == b.unusable); }
    };
    using ConnectionMap = QHash<ConnectionKey, QMetaObject::Connection>;

    template<typename SceneContext, typename CallContext, typename Setter>
    static void attachWatcherPriv(SceneContext *sceneContext, CallContext *callContext, Setter setter, QQuick3DObject *newO, QObject *oldO)
    {
        static_assert(std::is_base_of_v<QQuick3DObject, SceneContext>, "The scene context must be a QQuick3DObject");
        static_assert(std::is_member_function_pointer_v<Setter>, "The assumption is that the setter is a member function!");
        static_assert(sizeof(ConnectionKey::Handle) >= sizeof(Setter), "The handle needs to be able to store the value of the setter");
        // Sanity check: Make sure we have a valid context. If the sceneContext != callContext and we're here because the
        // watched object just got destroyed by the parent (QObject dtor) and that parent also is used as the sceneContext
        // then there's nothing more to do; all involved parties are being destroyed, so just bail out.
        const bool validContext = static_cast<QObject *>(sceneContext) != static_cast<QObject *>(callContext) ? qobject_cast<QQuick3DObject *>(sceneContext) != nullptr : true;
        if (validContext) {
            auto sceneManager = QQuick3DObjectPrivate::get(sceneContext)->sceneManager;
            auto &connectionMap = QQuick3DObjectPrivate::get(sceneContext)->connectionMap;
            union
            {
                Setter s;
                ConnectionKey::Handle h;
            }; s = setter;
            ConnectionKey key{static_cast<QObject *>(callContext), h};
            // disconnect previous destruction listener
            if (oldO) {
                // NOTE: If the old object is inside the QObject's dtor (e.g., QObject::destroyed) we can't
                // call deref (and there's no point anymore either).
                if (auto old3dO = qobject_cast<QQuick3DObject *>(oldO))
                    QQuick3DObjectPrivate::derefSceneManager(old3dO);

                auto it = connectionMap.constFind(key);
                if (it != connectionMap.cend()) {
                    QObject::disconnect(*it);
                    connectionMap.erase(it);
                }
            }

            // Watch new object
            if (newO) {
                if (sceneManager)
                    QQuick3DObjectPrivate::refSceneManager(newO, *sceneManager);
                auto connection = QObject::connect(newO, &QObject::destroyed, callContext, [callContext, setter](){ (callContext->*setter)(nullptr); });
                connectionMap.insert(key, connection);
            }
        }
    }

    /*!
      Attach a object-destroyed-watcher to an object that's not owned.
      There are few checks here just to keep it simple
      (The compiler should still fail with a varying degree of helpful messages when used incorrectly).

      \a sceneContext - ususally the same as the callContext and only different if the calledContext is a non-QQuick3DObject class
      (as is the case for QQuick3DShaderUtilsTextureInput)!
      \a callContext - The object watching another object
      \a setter - The function/slot that is called for the object (context).
      \a newO - The new object being watched
      \b oldO - The previous object that should no longer be watched.

      Note: The \a setter is a function that takes one argument with a discardable return value.
    */
    template<typename Context, typename Setter, typename Object3D>
    static void attachWatcher(Context *context, Setter setter, Object3D *newO, Object3D *oldO)
    {
        attachWatcherPriv(context, context, setter, newO, oldO);
    }

    static QQuick3DObjectPrivate *get(QQuick3DObject *item) { return item->d_func(); }
    static const QQuick3DObjectPrivate *get(const QQuick3DObject *item) { return item->d_func(); }
    static QSSGRenderGraphObject *updateSpatialNode(QQuick3DObject *o, QSSGRenderGraphObject *n) { return o->updateSpatialNode(n); }

    explicit QQuick3DObjectPrivate(Type t);
    ~QQuick3DObjectPrivate() override;
    void init(QQuick3DObject *parent);

    QQmlListProperty<QObject> data();
    QQmlListProperty<QObject> resources();
    QQmlListProperty<QQuick3DObject> children();

    QQmlListProperty<QQuickState> states();
    QQmlListProperty<QQuickTransition> transitions();

    QString state() const;
    void setState(const QString &);

    // data property
    static void data_append(QQmlListProperty<QObject> *, QObject *);
    static qsizetype data_count(QQmlListProperty<QObject> *);
    static QObject *data_at(QQmlListProperty<QObject> *, qsizetype);
    static void data_clear(QQmlListProperty<QObject> *);

    // resources property
    static QObject *resources_at(QQmlListProperty<QObject> *, qsizetype);
    static void resources_append(QQmlListProperty<QObject> *, QObject *);
    static qsizetype resources_count(QQmlListProperty<QObject> *);
    static void resources_clear(QQmlListProperty<QObject> *);

    // children property
    static void children_append(QQmlListProperty<QQuick3DObject> *, QQuick3DObject *);
    static qsizetype children_count(QQmlListProperty<QQuick3DObject> *);
    static QQuick3DObject *children_at(QQmlListProperty<QQuick3DObject> *, qsizetype);
    static void children_clear(QQmlListProperty<QQuick3DObject> *);

    void _q_resourceObjectDeleted(QObject *);
    void _q_cleanupContentItem2D();
    quint64 _q_createJSWrapper(QQmlV4ExecutionEnginePtr engine);

    enum ChangeType {
        Geometry = 0x01,
        SiblingOrder = 0x02,
        Visibility = 0x04,
        Opacity = 0x08,
        Destroyed = 0x10,
        Parent = 0x20,
        Children = 0x40,
        Rotation = 0x80,
        ImplicitWidth = 0x100,
        ImplicitHeight = 0x200,
        Enabled = 0x400,
    };

    Q_DECLARE_FLAGS(ChangeTypes, ChangeType)

    struct ChangeListener
    {
        using ChangeTypes = QQuick3DObjectPrivate::ChangeTypes;

        ChangeListener(QQuick3DObjectChangeListener *l = nullptr, ChangeTypes t = {}) : listener(l), types(t) {}

        ChangeListener(QQuick3DObjectChangeListener *l) : listener(l), types(Geometry) {}

        bool operator==(const ChangeListener &other) const
        {
            return listener == other.listener && types == other.types;
        }

        QQuick3DObjectChangeListener *listener;
        ChangeTypes types;
    };

    struct ExtraData
    {
        ExtraData();

        int hideRefCount;
        QObjectList resourcesList;

    };
    QLazilyAllocated<ExtraData> extra;

    QVector<QQuick3DObjectPrivate::ChangeListener> changeListeners;

    void addItemChangeListener(QQuick3DObjectChangeListener *listener, ChangeTypes types);
    void updateOrAddItemChangeListener(QQuick3DObjectChangeListener *listener, ChangeTypes types);
    void removeItemChangeListener(QQuick3DObjectChangeListener *, ChangeTypes types);

    QQuickStateGroup *_states();
    QQuickStateGroup *_stateGroup;

    enum DirtyType {
        TransformOrigin = 0x00000001,
        Transform = 0x00000002,
        BasicTransform = 0x00000004,
        Position = 0x00000008,
        Size = 0x00000010,

        ZValue = 0x00000020,
        Content = 0x00000040,
        Smooth = 0x00000080,
        OpacityValue = 0x00000100,
        ChildrenChanged = 0x00000200,
        ChildrenStackingChanged = 0x00000400,
        ParentChanged = 0x00000800,

        Clip = 0x00001000,
        Window = 0x00002000,

        EffectReference = 0x00008000,
        Visible = 0x00010000,
        HideReference = 0x00020000,
        Antialiasing = 0x00040000,

        InstanceRootChanged = 0x00080000,
        // When you add an attribute here, don't forget to update
        // dirtyToString()

        TransformUpdateMask = TransformOrigin | Transform | BasicTransform | Position | Window,
        ComplexTransformUpdateMask = Transform | Window,
        ContentUpdateMask = Size | Content | Smooth | Window | Antialiasing,
        ChildrenUpdateMask = ChildrenChanged | ChildrenStackingChanged | EffectReference | Window
    };

    quint32 dirtyAttributes;
    QString dirtyToString() const;
    void dirty(DirtyType);
    void addToDirtyList();
    void removeFromDirtyList();
    QQuick3DObject *nextDirtyItem;
    QQuick3DObject **prevDirtyItem;

    void setCulled(bool);

    QPointer<QQuick3DSceneManager> sceneManager;
    int sceneRefCount;

    QQuick3DObject *parentItem;

    QList<QQuick3DObject *> childItems;
    void addChild(QQuick3DObject *);
    void removeChild(QQuick3DObject *);
    void siblingOrderChanged();

    void refSceneManager(QQuick3DSceneManager &);
    void derefSceneManager();

    static void refSceneManager(QQuick3DObject *obj, QQuick3DSceneManager &mgr)
    {
        if (obj)
            QQuick3DObjectPrivate::get(obj)->refSceneManager(mgr);
    }
    static void derefSceneManager(QQuick3DObject *obj)
    {
        if (obj)
            QQuick3DObjectPrivate::get(obj)->derefSceneManager();
    }

    QQuick3DObject *subFocusItem;
    void updateSubFocusItem(QQuick3DObject *scope, bool focus);

    void itemChange(QQuick3DObject::ItemChange, const QQuick3DObject::ItemChangeData &);

    virtual void updatePolish() {}

    QSSGRenderGraphObject *spatialNode = nullptr;

    Type type = Type::Unknown;
    bool componentComplete = true;
    bool preSyncNeeded = false;
    bool culled;
    bool sharedResource = false;
    QQuick3DItem2D *contentItem2d = nullptr;
    ConnectionMap connectionMap;
    Q_QUICK3D_PROFILE_ID
};

Q_DECLARE_OPERATORS_FOR_FLAGS(QQuick3DObjectPrivate::ChangeTypes)
Q_DECLARE_TYPEINFO(QQuick3DObjectPrivate::ChangeListener, Q_PRIMITIVE_TYPE);
Q_DECLARE_TYPEINFO(QQuick3DObjectPrivate::ConnectionKey, Q_PRIMITIVE_TYPE);

inline size_t qHash(const QQuick3DObjectPrivate::ConnectionKey &con, size_t seed = 0) noexcept
{
    return qHashBits(&con, sizeof(QQuick3DObjectPrivate::ConnectionKey), seed);
}

QT_END_NAMESPACE

#endif // QSSGOBJECT_P_H