openblocks/src/objects/base/instance.h

#pragma once

#include "metadata.h"
#include <memory>
#include <string>

// Struct describing information about an instance
struct InstanceType {
    InstanceType* super; // May be null
    std::string className;
    InstanceConstructor constructor;
};

// Base class for all instances in the data model
class Instance : std::enable_shared_from_this<Instance> {
private:
    std::optional<std::weak_ptr<Instance>> parent;
    std::vector<std::shared_ptr<Instance>> children;
protected:
    Instance(InstanceType*);
    virtual ~Instance();
public:
    static InstanceType* TYPE;
    std::string name;

    // Instance is abstract, so it should not implement GetClass directly
    virtual InstanceType* GetClass() = 0;
    void SetParent(std::optional<std::shared_ptr<Instance>> newParent);
    std::optional<std::shared_ptr<Instance>> GetParent();
    inline const std::vector<std::shared_ptr<Instance>> GetChildren() { return children; }

    // Utility functions
    inline void AddChild(std::shared_ptr<Instance> object) { children.push_back(object); }
};

typedef std::shared_ptr<Instance> InstanceRef;
typedef std::weak_ptr<Instance> InstanceRefWeak;