namespace Atomic
{

class JSVM;

/// Helper base class for user-defined game logic components that hooks up to update events and forwards them to virtual functions similar to ScriptInstance class.
class ATOMIC_API JSComponent : public Component
{
    friend class JSComponentFactory;
    friend class JSComponentFile;

    enum EventFlags
    {
        USE_UPDATE = 0x1,
        USE_POSTUPDATE = 0x2,
        USE_FIXEDUPDATE = 0x4,
        USE_FIXEDPOSTUPDATE = 0x8
    };

public:

    OBJECT(JSComponent);

    /// Construct.
    JSComponent(Context* context);
    /// Destruct.
    virtual ~JSComponent();

    /// Register object factory.
    static void RegisterObject(Context* context);

    bool Load(Deserializer& source, bool setInstanceDefault);
    bool LoadXML(const XMLElement& source, bool setInstanceDefault);
    void ApplyAttributes();

    /// Get script attribute
    VariantMap& GetFieldValues() { return fieldValues_; }
    ResourceRef GetScriptAttr() const;
    JSComponentFile* GetComponentFile() { return componentFile_; }

    /// Match script name
    bool MatchScriptName(const String& path);

    /// Handle enabled/disabled state change. Changes update event subscription.
    virtual void OnSetEnabled();

    /// Set what update events should be subscribed to. Use this for optimization: by default all are in use. Note that this is not an attribute and is not saved or network-serialized, therefore it should always be called eg. in the subclass constructor.
    void SetUpdateEventMask(unsigned char mask);

    /// Return what update events are subscribed to.
    unsigned char GetUpdateEventMask() const { return updateEventMask_; }
    /// Return whether the DelayedStart() function has been called.
    bool IsDelayedStartCalled() const { return delayedStartCalled_; }

    /// Set script attribute.
    void SetScriptAttr(const ResourceRef& value);
    void SetComponentFile(JSComponentFile* cfile);

    void SetDestroyed() { destroyed_ = true; }

    void InitInstance(bool hasArgs = false, int argIdx = 0);

protected:
    /// Handle scene node being assigned at creation.
    virtual void OnNodeSet(Node* node);
    /// Handle scene being assigned.
    virtual void OnSceneSet(Scene* scene);

private:
    /// Subscribe/unsubscribe to update events based on current enabled state and update event mask.
    void UpdateEventSubscription();
    /// Handle scene update event.
    void HandleSceneUpdate(StringHash eventType, VariantMap& eventData);
    /// Handle scene post-update event.
    void HandleScenePostUpdate(StringHash eventType, VariantMap& eventData);
#ifdef ATOMIC_PHYSICS
    /// Handle physics pre-step event.
    void HandlePhysicsPreStep(StringHash eventType, VariantMap& eventData);
    /// Handle physics post-step event.
    void HandlePhysicsPostStep(StringHash eventType, VariantMap& eventData);
#endif

    void CallScriptMethod(const String& name, bool passValue = false, float value = 0.0f);

    /// Called when the component is added to a scene node. Other components may not yet exist.
    virtual void Start();
    /// Called before the first update. At this point all other components of the node should exist. Will also be called if update events are not wanted; in that case the event is immediately unsubscribed afterward.
    virtual void DelayedStart();
    /// Called when the component is detached from a scene node, usually on destruction. Note that you will no longer have access to the node and scene at that point.
    virtual void Stop() {}
    /// Called on scene update, variable timestep.
    virtual void Update(float timeStep);
    /// Called on scene post-update, variable timestep.
    virtual void PostUpdate(float timeStep);
    /// Called on physics update, fixed timestep.
    virtual void FixedUpdate(float timeStep);
    /// Called on physics post-update, fixed timestep.
    virtual void FixedPostUpdate(float timeStep);

    void UpdateReferences(bool remove = false);

    /// Requested event subscription mask.
    unsigned char updateEventMask_;
    /// Current event subscription mask.
    unsigned char currentEventMask_;

    bool instanceInitialized_;
    bool started_;
    bool destroyed_;
    bool scriptClassInstance_;

    /// Flag for delayed start.
    bool delayedStartCalled_;



    bool loading_;
    WeakPtr<JSVM> vm_;
    SharedPtr<JSComponentFile> componentFile_;

    VariantMap fieldValues_;

};

}
