include/rive/viewmodel/viewmodel_instance_value.hpp

#ifndef _RIVE_VIEW_MODEL_INSTANCE_VALUE_HPP_
#define _RIVE_VIEW_MODEL_INSTANCE_VALUE_HPP_
#include "rive/generated/viewmodel/viewmodel_instance_value_base.hpp"
#include "rive/animation/state_machine_input_instance.hpp"
#include "rive/viewmodel/viewmodel_property.hpp"
#include "rive/dependency_helper.hpp"
#include "rive/lazy_vector.hpp"
#include "rive/viewmodel/viewmodel_value_dependent.hpp"
#include "rive/component.hpp"
#include "rive/component_dirt.hpp"
#include "rive/refcnt.hpp"
#include <stdio.h>
#include <list>

namespace rive
{
class ViewModelInstance;
class ViewModelInstanceValueDelegate
{
public:
    virtual void valueChanged() = 0;
};

enum class ValueFlags : uint8_t
{
    none = 0,
    valueChanged = 1 << 1,
    delegatesChanged = 1 << 2,
    delegating = 1 << 3,
};

class SuppressDelegation;

class ViewModelInstanceValue : public ViewModelInstanceValueBase,
                               public RefCnt<ViewModelInstanceValue>,
                               public Triggerable
{
    friend class SuppressDelegation;

private:
    ViewModelProperty* m_ViewModelProperty = nullptr;
    static std::string defaultName;
    ValueFlags m_changeFlags = ValueFlags::none;
    LazyVector<ViewModelInstanceValueDelegate*> m_delegates;
    LazyVector<ViewModelInstanceValueDelegate*> m_delegatesCopy;
    void registerSymbol();

public:
    void addDelegate(ViewModelInstanceValueDelegate* delegate);
    void removeDelegate(ViewModelInstanceValueDelegate* delegate);

    // Required by DependencyHelper's CRTP base. onComponentDirty is never
    // actually invoked on ViewModelInstanceValue's dependency chain — the
    // previous design stored &local_param here (a dangling pointer) and was
    // saved only by nothing reading it. We keep a stub returning nullptr; if
    // anything ever calls it, the deref will crash loudly rather than
    // silently use freed stack memory. The stub also satisfies the CRTP
    // contract so the templated onComponentDirty member can instantiate.
    rcp<ViewModelInstance>* dependencyRoot() const { return nullptr; }

protected:
    // Kept as a member rather than a base because ViewModelInstanceValue
    // already inherits DependencyHelper transitively via Component (see
    // ViewModelInstanceValueBase). Inheriting a second DependencyHelper
    // would make `addDependent` ambiguous across the two instantiations.
    // The 8 B savings from the CRTP refactor still apply — the helper no
    // longer stores its own root pointer.
    DependencyHelper<rcp<ViewModelInstance>,
                     ViewModelValueDependent,
                     ViewModelInstanceValue>
        m_DependencyHelper;
    ViewModelInstance* m_viewModelInstance = nullptr;
    void addDirt(ComponentDirt value);

    // Suppress/restore calling delegates.
    bool suppressDelegation();
    void restoreDelegation();

public:
    StatusCode onAddedDirty(CoreContext* context) override;
    StatusCode import(ImportStack& importStack) override;
    void viewModelProperty(ViewModelProperty* value);
    ViewModelProperty* viewModelProperty();
    void viewModelInstance(ViewModelInstance* value);
#ifdef WITH_RIVE_TOOLS
    ViewModelInstance* viewModelInstance() const { return m_viewModelInstance; }
#endif
    void addDependent(ViewModelValueDependent* value);
    void removeDependent(ViewModelValueDependent* value);
    virtual void setRoot(rcp<ViewModelInstance> value);
    virtual void advanced();
    bool hasChanged();
    void onValueChanged();
    const std::string& name() const;
    const std::vector<ViewModelValueDependent*>& dependents() const
    {
        return m_DependencyHelper.dependents();
    }
};

class SuppressDelegation
{
public:
    SuppressDelegation(ViewModelInstanceValue* value) :
        m_value(value), m_suppressed(value->suppressDelegation())
    {}

    ~SuppressDelegation()
    {
        if (m_suppressed)
        {
            m_value->restoreDelegation();
        }
    }

private:
    ViewModelInstanceValue* m_value = nullptr;
    bool m_suppressed;
};

} // namespace rive

#endif