Scope.h

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/*
 * Copyright (C) 2025 by
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 * and
 *   Neuroinformatics and Cognitive Robotics Labs (NICR) at TU Ilmenau, GERMANY
 * All rights reserved.
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 * Contact: info@mira-project.org
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 * Commercial Usage:
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#ifndef _MIRA_XML_MACROS_SCOPE_H_
#define _MIRA_XML_MACROS_SCOPE_H_

#include <string>
#include <unordered_map>

#include <xml/macros/IMacro.h>

namespace mira::xmlmacros {

struct Identifier
{
    std::string xmlns;
    std::string name;

    [[nodiscard]] std::string toString() const
    {
        return xmlns + ":" + name;
    }
};

using Definitions = std::unordered_map<std::string, xmlmacros::MacroPtr>;

struct Scope
{
    using Ptr = std::shared_ptr<Scope>;

    Scope::Ptr parent = nullptr;

    // Set of definitions for each namespace.
    std::unordered_map<std::string, Definitions> namespaces;

    [[nodiscard]] MacroPtr findOptional(const Identifier& id) const
    {
        auto ns = namespaces.find(id.xmlns);

        if (ns != namespaces.end()) {
            auto it = ns->second.find(id.name);

            if (it != ns->second.end()) {
                return it->second;
            }
        }

        if (parent != nullptr) {
            return parent->findOptional(id);
        }

        return nullptr;
    }

    [[nodiscard]] MacroPtr find(const Identifier& name) const
    {
        auto ptr = findOptional(name);

        if (ptr == nullptr) {
            MIRA_THROW(XInvalidConfig,
                       "No definition for macro \"" + name.xmlns + ":" + name.name + "\" found.");
        }

        return ptr;
    }

    void define(Identifier id, MacroPtr macro)
    {
        auto ns = namespaces.find(id.xmlns);

        if (ns == namespaces.end()) {
            namespaces[id.xmlns] = {};
            ns = namespaces.find(id.xmlns);
        }

        if (ns->second.find(id.name) != ns->second.end()) {
            MIRA_THROW(XInvalidConfig, "Macro \"" + id.toString() + "\" already defined in this scope.");
        }

        ns->second.insert(std::make_pair(std::move(id.name), std::move(macro)));
    }

    void collectGarbage()
    {
        for (auto& [_, ns] : namespaces) {
            std::vector<std::remove_reference_t<decltype(ns)>::iterator> toErase;

            for (auto it = ns.begin(); it != ns.end(); ++it) {
                if (it->second.use_count() == 1) {
                    toErase.emplace_back(it);
                }
            }

            for (auto it : toErase) {
                ns.erase(it);
            }
        }
    }
}; // struct Scope

using ScopePtr = Scope::Ptr;

} // namespace mira::xmlmacros

#endif // _MIRA_XML_MACROS_SCOPE_H_