poc-links/include/mixins/LazyLinkMixin.h

#pragma once
#include <iostream>
#include "ifaces/INode.h"
#include "links/LeafLink.h"
#include "links/OneToManyLink.h"
#include <memory>

template <class TFinalNode>
class LazyLinkMixin : public INode {
public:
    void linkChild(const NodePtr& childNode) override {
        lazyInit();
        upgradeLinkIfNeeded();
        LinkPtr childLink = childNode->getLink();
        childLink->setParent(link_);
        link_->addChild(childLink);
    }

    void unlinkParent() override {
        lazyInit();
        LinkPtr parentLink = link_->getParent();
        if (!parentLink) return;
        parentLink->removeChild(this->getLink());
        link_->setParent(nullptr);
    }

    LinkPtr getLink() override {
        lazyInit();
        return link_;
    }

    ~LazyLinkMixin() override {
        std::cout << "--- Destructor called for: " << "LazyLinkMixin" << "\n";
    }

protected:
    virtual std::shared_ptr<TFinalNode> getShared() = 0;
    NodePtr getSelf() override { return getShared(); }

private:
    void lazyInit() {
        if (!link_) {
            link_ = std::make_shared<LeafLink>(getSelf());
        }
    }

    void upgradeLinkIfNeeded() {
        if (!std::dynamic_pointer_cast<LeafLink>(link_)) return;
        auto newLink = std::make_shared<OneToManyLink>(getSelf());
        if (auto parentLink = link_->getParent()) {
            parentLink->removeChild(link_);
            parentLink->addChild(newLink);
        }
        newLink->setParent(link_->getParent());
        link_ = newLink;
    }

    void downgradeLinkIfPossible() {
        if (link_->getChildren().empty() && std::dynamic_pointer_cast<OneToManyLink>(link_)) {
            auto newLink = std::make_shared<LeafLink>(getSelf());
            if (auto parentLink = link_->getParent()) {
                parentLink->removeChild(link_);
                parentLink->addChild(newLink);
            }
            newLink->setParent(link_->getParent());
            link_ = newLink;
        }
    }

    LinkPtr link_;
};