#pragma once

#include <hex.hpp>
#include <hex/helpers/concepts.hpp>

#include <pl/pattern_language.hpp>
#include <hex/api/imhex_api.hpp>
#include <hex/api/event.hpp>

#include <functional>
#include <map>
#include <span>
#include <string>
#include <string_view>
#include <unordered_map>
#include <vector>

#include <nlohmann/json_fwd.hpp>

using ImGuiDataType = int;
using ImGuiInputTextFlags = int;

namespace hex {

    class View;
    class LanguageDefinition;

    namespace dp {
        class Node;
    }
    namespace prv {
        class Provider;
    }

    /*
        The Content Registry is the heart of all features in ImHex that are in some way extendable by Plugins.
        It allows you to add/register new content that will be picked up and used by the ImHex core or by other
        plugins when needed.
    */
    namespace ContentRegistry {

        /* Settings Registry. Allows adding of new entries into the ImHex preferences window. */
        namespace Settings {

            namespace impl {
                using Callback = std::function<bool(const std::string &, nlohmann::json &)>;

                struct Entry {
                    std::string name;
                    bool requiresRestart;
                    Callback callback;
                };

                struct Category {
                    std::string name;
                    size_t slot = 0;

                    bool operator<(const Category &other) const {
                        return name < other.name;
                    }

                    explicit operator const std::string &() const {
                        return name;
                    }
                };

                void load();
                void store();
                void clear();

                std::map<Category, std::vector<Entry>> &getEntries();
                std::map<std::string, std::string> &getCategoryDescriptions();
                nlohmann::json getSetting(const std::string &unlocalizedCategory, const std::string &unlocalizedName);
                nlohmann::json &getSettingsData();
            }


            /**
             * @brief Adds a new integer setting entry
             * @param unlocalizedCategory The category of the setting
             * @param unlocalizedName The name of the setting
             * @param defaultValue The default value of the setting
             * @param callback The callback that will be called when the settings item in the preferences window is rendered
             * @param requiresRestart Whether the setting requires a restart to take effect
             */
            void add(const std::string &unlocalizedCategory, const std::string &unlocalizedName, i64 defaultValue, const impl::Callback &callback, bool requiresRestart = false);

            /**
             * @brief Adds a new string setting entry
             * @param unlocalizedCategory The category of the setting
             * @param unlocalizedName The name of the setting
             * @param defaultValue The default value of the setting
             * @param callback The callback that will be called when the settings item in the preferences window is rendered
             * @param requiresRestart Whether the setting requires a restart to take effect
             */
            void add(const std::string &unlocalizedCategory, const std::string &unlocalizedName, const std::string &defaultValue, const impl::Callback &callback, bool requiresRestart = false);

            /**
             * @brief Adds a new string list setting entry
             * @param unlocalizedCategory The category of the setting
             * @param unlocalizedName The name of the setting
             * @param defaultValue The default value of the setting
             * @param callback The callback that will be called when the settings item in the preferences window is rendered
             * @param requiresRestart Whether the setting requires a restart to take effect
             */
            void add(const std::string &unlocalizedCategory, const std::string &unlocalizedName, const std::vector<std::string> &defaultValue, const impl::Callback &callback, bool requiresRestart = false);

            /**
             * @brief Adds a description to a given category
             * @param unlocalizedCategory The name of the category
             * @param unlocalizedCategoryDescription The description of the category
             */
            void addCategoryDescription(const std::string &unlocalizedCategory, const std::string &unlocalizedCategoryDescription);

            /**
             * @brief Writes a integer value to the settings file
             * @param unlocalizedCategory The category of the setting
             * @param unlocalizedName The name of the setting
             * @param value The value to write
             */
            void write(const std::string &unlocalizedCategory, const std::string &unlocalizedName, i64 value);

            /**
             * @brief Writes a string value to the settings file
             * @param unlocalizedCategory The category of the setting
             * @param unlocalizedName The name of the setting
             * @param value The value to write
             */
            void write(const std::string &unlocalizedCategory, const std::string &unlocalizedName, const std::string &value);

            /**
             * @brief Writes a string list value to the settings file
             * @param unlocalizedCategory The category of the setting
             * @param unlocalizedName The name of the setting
             * @param value The value to write
             */
            void write(const std::string &unlocalizedCategory, const std::string &unlocalizedName, const std::vector<std::string> &value);

            /**
             * @brief Reads an integer value from the settings file
             * @param unlocalizedCategory The category of the setting
             * @param unlocalizedName The name of the setting
             * @param defaultValue The default value of the setting
             * @return The value of the setting
             */
            i64 read(const std::string &unlocalizedCategory, const std::string &unlocalizedName, i64 defaultValue);

            /**
             * @brief Reads a string value from the settings file
             * @param unlocalizedCategory The category of the setting
             * @param unlocalizedName The name of the setting
             * @param defaultValue The default value of the setting
             * @return The value of the setting
             */
            std::string read(const std::string &unlocalizedCategory, const std::string &unlocalizedName, const std::string &defaultValue);

            /**
             * @brief Reads a string list value from the settings file
             * @param unlocalizedCategory The category of the setting
             * @param unlocalizedName The name of the setting
             * @param defaultValue The default value of the setting
             * @return The value of the setting
             */
            std::vector<std::string> read(const std::string &unlocalizedCategory, const std::string &unlocalizedName, const std::vector<std::string> &defaultValue = {});

        }

        /* Command Palette Command Registry. Allows adding of new commands to the command palette */
        namespace CommandPaletteCommands {

            enum class Type : u32 {
                SymbolCommand,
                KeywordCommand
            };

            namespace impl {

                struct QueryResult {
                    std::string name;
                    std::function<void(std::string)> callback;
                };

                using DisplayCallback = std::function<std::string(std::string)>;
                using ExecuteCallback = std::function<void(std::string)>;
                using QueryCallback   = std::function<std::vector<QueryResult>(std::string)>;

                struct Entry {
                    Type type;
                    std::string command;
                    std::string unlocalizedDescription;
                    DisplayCallback displayCallback;
                    ExecuteCallback executeCallback;
                };

                struct Handler {
                    Type type;
                    std::string command;
                    QueryCallback queryCallback;
                    DisplayCallback displayCallback;
                };

                std::vector<impl::Entry> &getEntries();
                std::vector<impl::Handler> &getHandlers();

            }

            /**
             * @brief Adds a new command to the command palette
             * @param type The type of the command
             * @param command The command to add
             * @param unlocalizedDescription The description of the command
             * @param displayCallback The callback that will be called when the command is displayed in the command palette
             * @param executeCallback The callback that will be called when the command is executed
             */
            void add(
                Type type,
                const std::string &command,
                const std::string &unlocalizedDescription,
                const impl::DisplayCallback &displayCallback,
                const impl::ExecuteCallback &executeCallback = [](auto) {});

            /**
             * @brief Adds a new command handler to the command palette
             * @param type The type of the command
             * @param command The command to add
             * @param unlocalizedDescription The description of the command
             * @param queryCallback The callback that will be called when the command palette wants to load the name and callback items
             * @param displayCallback The callback that will be called when the command is displayed in the command palette
             */
            void addHandler(
                Type type,
                const std::string &command,
                const impl::QueryCallback &queryCallback,
                const impl::DisplayCallback &displayCallback);
        }

        /* Pattern Language Function Registry. Allows adding of new functions that may be used inside the pattern language */
        namespace PatternLanguage {

            namespace impl {

                using VisualizerFunctionCallback = std::function<void(pl::ptrn::Pattern&, pl::ptrn::Iteratable&, bool, std::span<const pl::core::Token::Literal>)>;

                struct FunctionDefinition {
                    pl::api::Namespace ns;
                    std::string name;

                    pl::api::FunctionParameterCount parameterCount;
                    pl::api::FunctionCallback callback;

                    bool dangerous;
                };

                struct Visualizer {
                    u32 parameterCount;
                    VisualizerFunctionCallback callback;
                };

                std::map<std::string, Visualizer> &getVisualizers();
                std::map<std::string, pl::api::PragmaHandler> &getPragmas();
                std::vector<impl::FunctionDefinition> &getFunctions();

            }

            /**
             * @brief Configures the pattern language runtime using ImHex's default settings
             * @param runtime The pattern language runtime to configure
             * @param provider The provider to use for data access
             */
            void configureRuntime(pl::PatternLanguage &runtime, prv::Provider *provider);

            /**
             * @brief Adds a new pragma to the pattern language
             * @param name The name of the pragma
             * @param handler The handler that will be called when the pragma is encountered
             */
            void addPragma(const std::string &name, const pl::api::PragmaHandler &handler);

            /**
             * @brief Adds a new function to the pattern language
             * @param ns The namespace of the function
             * @param name The name of the function
             * @param parameterCount The amount of parameters the function takes
             * @param func The function callback
             */
            void addFunction(const pl::api::Namespace &ns, const std::string &name, pl::api::FunctionParameterCount parameterCount, const pl::api::FunctionCallback &func);

            /**
             * @brief Adds a new dangerous function to the pattern language
             * @note Dangerous functions are functions that require the user to explicitly allow them to be used
             * @param ns The namespace of the function
             * @param name The name of the function
             * @param parameterCount The amount of parameters the function takes
             * @param func The function callback
             */
            void addDangerousFunction(const pl::api::Namespace &ns, const std::string &name, pl::api::FunctionParameterCount parameterCount, const pl::api::FunctionCallback &func);

            /**
             * @brief Adds a new visualizer to the pattern language
             * @note Visualizers are extensions to the [[hex::visualize]] attribute, used to visualize data
             * @param name The name of the visualizer
             * @param func The function callback
             * @param parameterCount The amount of parameters the function takes
             */
            void addVisualizer(const std::string &name, const impl::VisualizerFunctionCallback &func, u32 parameterCount);

        }

        /* View Registry. Allows adding of new windows */
        namespace Views {

            namespace impl {

                void add(View *view);
                std::map<std::string, View *> &getEntries();

            }

            /**
             * @brief Adds a new view to ImHex
             * @tparam T The custom view class that extends View
             * @tparam Args Arguments types
             * @param args Arguments passed to the constructor of the view
             */
            template<std::derived_from<View> T, typename... Args>
            void add(Args &&...args) {
                return impl::add(new T(std::forward<Args>(args)...));
            }

            /**
             * @brief Gets a view by its unlocalized name
             * @param unlocalizedName The unlocalized name of the view
             * @return The view if it exists, nullptr otherwise
             */
            View *getViewByName(const std::string &unlocalizedName);
        }

        /* Tools Registry. Allows adding new entries to the tools window */
        namespace Tools {

            namespace impl {

                using Callback = std::function<void()>;

                struct Entry {
                    std::string name;
                    Callback function;
                    bool detached;
                };

                std::vector<impl::Entry> &getEntries();

            }

            /**
             * @brief Adds a new tool to the tools window
             * @param unlocalizedName The unlocalized name of the tool
             * @param function The function that will be called to draw the tool
             */
            void add(const std::string &unlocalizedName, const impl::Callback &function);
        }

        /* Data Inspector Registry. Allows adding of new types to the data inspector */
        namespace DataInspector {

            enum class NumberDisplayStyle
            {
                Decimal,
                Hexadecimal,
                Octal
            };

            namespace impl {

                using DisplayFunction   = std::function<std::string()>;
                using EditingFunction   = std::function<std::vector<u8>(std::string, std::endian)>;
                using GeneratorFunction = std::function<DisplayFunction(const std::vector<u8> &, std::endian, NumberDisplayStyle)>;

                struct Entry {
                    std::string unlocalizedName;
                    size_t requiredSize;
                    size_t maxSize;
                    impl::GeneratorFunction generatorFunction;
                    std::optional<impl::EditingFunction> editingFunction;
                };

                std::vector<impl::Entry> &getEntries();

            }

            /**
             * @brief Adds a new entry to the data inspector
             * @param unlocalizedName The unlocalized name of the entry
             * @param requiredSize The minimum required number of bytes available for the entry to appear
             * @param displayGeneratorFunction The function that will be called to generate the display function
             * @param editingFunction The function that will be called to edit the data
             */
            void add(const std::string &unlocalizedName, size_t requiredSize, impl::GeneratorFunction displayGeneratorFunction, std::optional<impl::EditingFunction> editingFunction = std::nullopt);

            /**
             * @brief Adds a new entry to the data inspector
             * @param unlocalizedName The unlocalized name of the entry
             * @param requiredSize The minimum required number of bytes available for the entry to appear
             * @param maxSize The maximum number of bytes to read from the data
             * @param displayGeneratorFunction The function that will be called to generate the display function
             * @param editingFunction The function that will be called to edit the data
             */
            void add(const std::string &unlocalizedName, size_t requiredSize, size_t maxSize, impl::GeneratorFunction displayGeneratorFunction, std::optional<impl::EditingFunction> editingFunction = std::nullopt);
        }

        /* Data Processor Node Registry. Allows adding new processor nodes to be used in the data processor */
        namespace DataProcessorNode {

            namespace impl {

                using CreatorFunction = std::function<std::unique_ptr<dp::Node>()>;

                struct Entry {
                    std::string category;
                    std::string name;
                    CreatorFunction creatorFunction;
                };

                void add(const Entry &entry);

                std::vector<impl::Entry> &getEntries();
            }


            /**
             * @brief Adds a new node to the data processor
             * @tparam T The custom node class that extends dp::Node
             * @tparam Args Arguments types
             * @param unlocalizedCategory The unlocalized category name of the node
             * @param unlocalizedName The unlocalized name of the node
             * @param args Arguments passed to the constructor of the node
             */
            template<std::derived_from<dp::Node> T, typename... Args>
            void add(const std::string &unlocalizedCategory, const std::string &unlocalizedName, Args &&...args) {
                add(impl::Entry {
                    unlocalizedCategory.c_str(),
                    unlocalizedName.c_str(),
                    [=] {
                        auto node = std::make_unique<T>(std::forward<Args>(args)...);
                        node->setUnlocalizedName(unlocalizedName);
                        return node;
                    }
                });
            }

            /**
             * @brief Adds a separator to the data processor right click menu
             */
            void addSeparator();

        }

        /* Language Registry. Allows together with the LangEntry class and the _lang user defined literal to add new languages */
        namespace Language {

            /**
             * @brief Loads localization information from json data
             * @param data The language data
             */
            void addLocalization(const nlohmann::json &data);

            namespace impl {

                std::map<std::string, std::string> &getLanguages();
                std::map<std::string, std::vector<LanguageDefinition>> &getLanguageDefinitions();

            }

        }

        /* Interface Registry. Allows adding new items to various interfaces */
        namespace Interface {

            namespace impl {

                using DrawCallback      = std::function<void()>;
                using MenuCallback      = std::function<void()>;
                using EnabledCallback   = std::function<bool()>;
                using LayoutFunction    = std::function<void(u32)>;
                using ClickCallback     = std::function<void()>;

                struct Layout {
                    std::string unlocalizedName;
                    LayoutFunction callback;
                };

                struct MainMenuItem {
                    std::string unlocalizedName;
                };

                struct MenuItem {
                    std::vector<std::string> unlocalizedNames;
                    Shortcut shortcut;
                    MenuCallback callback;
                    EnabledCallback enabledCallback;
                };

                struct SidebarItem {
                    std::string icon;
                    DrawCallback callback;
                };

                struct TitleBarButton {
                    std::string icon;
                    std::string unlocalizedTooltip;
                    ClickCallback callback;
                };

                constexpr static auto SeparatorValue = "$SEPARATOR$";
                constexpr static auto SubMenuValue = "$SUBMENU$";

                std::multimap<u32, impl::MainMenuItem> &getMainMenuItems();
                std::multimap<u32, impl::MenuItem> &getMenuItems();

                std::vector<impl::DrawCallback> &getWelcomeScreenEntries();
                std::vector<impl::DrawCallback> &getFooterItems();
                std::vector<impl::DrawCallback> &getToolbarItems();
                std::vector<impl::SidebarItem> &getSidebarItems();
                std::vector<impl::TitleBarButton> &getTitleBarButtons();

                std::vector<impl::Layout> &getLayouts();

            }

            /**
             * @brief Adds a new top-level main menu entry
             * @param unlocalizedName The unlocalized name of the entry
             * @param priority The priority of the entry. Lower values are displayed first
             */
            void registerMainMenuItem(const std::string &unlocalizedName, u32 priority);

            /**
             * @brief Adds a new main menu entry
             * @param unlocalizedMainMenuNames The unlocalized names of the main menu entries
             * @param priority The priority of the entry. Lower values are displayed first
             * @param shortcut The shortcut to use for the entry
             * @param function The function to call when the entry is clicked
             * @param enabledCallback The function to call to determine if the entry is enabled
             * @param view The view to use for the entry. If nullptr, the shortcut will work globally
             */
            void addMenuItem(const std::vector<std::string> &unlocalizedMainMenuNames, u32 priority, const Shortcut &shortcut, const impl::MenuCallback &function, const impl::EnabledCallback& enabledCallback = []{ return true; }, View *view = nullptr);

            /**
             * @brief Adds a new main menu sub-menu entry
             * @param unlocalizedMainMenuNames The unlocalized names of the main menu entries
             * @param priority The priority of the entry. Lower values are displayed first
             * @param function The function to call when the entry is clicked
             * @param enabledCallback The function to call to determine if the entry is enabled
             * @param view The view to use for the entry. If nullptr, the shortcut will work globally
             */
            void addMenuItemSubMenu(std::vector<std::string> unlocalizedMainMenuNames, u32 priority, const impl::MenuCallback &function, const impl::EnabledCallback& enabledCallback = []{ return true; });

            /**
             * @brief Adds a new main menu separator
             * @param unlocalizedMainMenuNames The unlocalized names of the main menu entries
             * @param priority The priority of the entry. Lower values are displayed first
             */
            void addMenuItemSeparator(std::vector<std::string> unlocalizedMainMenuNames, u32 priority);


            /**
             * @brief Adds a new welcome screen entry
             * @param function The function to call to draw the entry
             */
            void addWelcomeScreenEntry(const impl::DrawCallback &function);

            /**
             * @brief Adds a new footer item
             * @param function The function to call to draw the item
             */
            void addFooterItem(const impl::DrawCallback &function);

            /**
             * @brief Adds a new toolbar item
             * @param function The function to call to draw the item
             */
            void addToolbarItem(const impl::DrawCallback &function);

            /**
             * @brief Adds a new sidebar item
             * @param icon The icon to use for the item
             * @param function The function to call to draw the item
             */
            void addSidebarItem(const std::string &icon, const impl::DrawCallback &function);

            /**
             * @brief Adds a new title bar button
             * @param icon The icon to use for the button
             * @param unlocalizedTooltip The unlocalized tooltip to use for the button
             * @param function The function to call when the button is clicked
             */
            void addTitleBarButton(const std::string &icon, const std::string &unlocalizedTooltip, const impl::ClickCallback &function);


            /**
             * @brief Adds a new layout definition to the Layout menu
             * @param unlocalizedName The unlocalized name of the layout
             * @param function The function to call to setup the layout
             */
            void addLayout(const std::string &unlocalizedName, const impl::LayoutFunction &function);

        }

        /* Provider Registry. Allows adding new data providers to be created from the UI */
        namespace Provider {

            namespace impl {

                void addProviderName(const std::string &unlocalizedName);

                std::vector<std::string> &getEntries();

            }

            /**
             * @brief Adds a new provider to the list of providers
             * @tparam T The provider type that extends hex::prv::Provider
             * @param addToList Whether to display the provider in the Other Providers list in the welcome screen and File menu
             */
            template<std::derived_from<hex::prv::Provider> T>
            void add(bool addToList = true) {
                auto typeName = T().getTypeName();

                (void)EventManager::subscribe<RequestCreateProvider>([expectedName = typeName](const std::string &name, bool skipLoadInterface, hex::prv::Provider **provider) {
                    if (name != expectedName) return;

                    prv::Provider *newProvider = new T();

                    hex::ImHexApi::Provider::add(newProvider, skipLoadInterface);

                    if (provider != nullptr)
                        *provider = newProvider;
                });

                if (addToList)
                    impl::addProviderName(typeName);
            }

        }

        /* Data Formatter Registry. Allows adding formatters that are used in the Copy-As menu for example */
        namespace DataFormatter {

            namespace impl {

                using Callback = std::function<std::string(prv::Provider *provider, u64 address, size_t size)>;
                struct Entry {
                    std::string unlocalizedName;
                    Callback callback;
                };

                std::vector<impl::Entry> &getEntries();

            }


            /**
             * @brief Adds a new data formatter
             * @param unlocalizedName The unlocalized name of the formatter
             * @param callback The function to call to format the data
             */
            void add(const std::string &unlocalizedName, const impl::Callback &callback);

        }

        /* File Handler Registry. Allows adding handlers for opening files specific file types */
        namespace FileHandler {

            namespace impl {

                using Callback = std::function<bool(std::fs::path)>;
                struct Entry {
                    std::vector<std::string> extensions;
                    Callback callback;
                };

                std::vector<impl::Entry> &getEntries();

            }

            /**
             * @brief Adds a new file handler
             * @param extensions The file extensions to handle
             * @param callback The function to call to handle the file
             */
            void add(const std::vector<std::string> &extensions, const impl::Callback &callback);

        }

        /* Hex Editor Registry. Allows adding new functionality to the hex editor */
        namespace HexEditor {

            class DataVisualizer {
            public:
                DataVisualizer(u16 bytesPerCell, u16 maxCharsPerCell)
                    : m_bytesPerCell(bytesPerCell), m_maxCharsPerCell(maxCharsPerCell) {}

                virtual ~DataVisualizer() = default;

                virtual void draw(u64 address, const u8 *data, size_t size, bool upperCase) = 0;
                virtual bool drawEditing(u64 address, u8 *data, size_t size, bool upperCase, bool startedEditing) = 0;

                [[nodiscard]] u16 getBytesPerCell() const { return this->m_bytesPerCell; }
                [[nodiscard]] u16 getMaxCharsPerCell() const { return this->m_maxCharsPerCell; }

            protected:
                const static int TextInputFlags;

                bool drawDefaultScalarEditingTextBox(u64 address, const char *format, ImGuiDataType dataType, u8 *data, ImGuiInputTextFlags flags) const;
                bool drawDefaultTextEditingTextBox(u64 address, std::string &data, ImGuiInputTextFlags flags) const;
            private:
                u16 m_bytesPerCell;
                u16 m_maxCharsPerCell;
            };

            namespace impl {

                void addDataVisualizer(const std::string &unlocalizedName, DataVisualizer *visualizer);

                std::map<std::string, DataVisualizer*> &getVisualizers();

            }

            /**
             * @brief Adds a new cell data visualizer
             * @tparam T The data visualizer type that extends hex::DataVisualizer
             * @param unlocalizedName The unlocalized name of the data visualizer
             * @param args The arguments to pass to the constructor of the data visualizer
             */
            template<std::derived_from<DataVisualizer> T, typename... Args>
            void addDataVisualizer(const std::string &unlocalizedName, Args &&...args) {
                return impl::addDataVisualizer(unlocalizedName, new T(std::forward<Args>(args)...));
            }

        }

        /* Hash Registry. Allows adding new hashes to the Hash view */
        namespace Hashes {

            class Hash {
            public:
                explicit Hash(std::string unlocalizedName) : m_unlocalizedName(std::move(unlocalizedName)) {}

                class Function {
                public:
                    using Callback = std::function<std::vector<u8>(const Region&, prv::Provider *)>;

                    Function(Hash *type, std::string name, Callback callback)
                        : m_type(type), m_name(std::move(name)), m_callback(std::move(callback)) {

                    }

                    [[nodiscard]] Hash *getType() { return this->m_type; }
                    [[nodiscard]] const Hash *getType() const { return this->m_type; }
                    [[nodiscard]] const std::string &getName() const { return this->m_name; }

                    const std::vector<u8>& get(const Region& region, prv::Provider *provider) {
                        if (this->m_cache.empty()) {
                            this->m_cache = this->m_callback(region, provider);
                        }

                        return this->m_cache;
                    }

                    void reset() {
                        this->m_cache.clear();
                    }

                private:
                    Hash *m_type;
                    std::string m_name;
                    Callback m_callback;

                    std::vector<u8> m_cache;
                };

                virtual void draw() { }
                [[nodiscard]] virtual Function create(std::string name) = 0;

                [[nodiscard]] virtual nlohmann::json store() const = 0;
                virtual void load(const nlohmann::json &json) = 0;

                [[nodiscard]] const std::string &getUnlocalizedName() const {
                    return this->m_unlocalizedName;
                }

            protected:
                [[nodiscard]] Function create(const std::string &name, const Function::Callback &callback) {
                    return { this, name, callback };
                }

            private:
                std::string m_unlocalizedName;
            };

            namespace impl {

                std::vector<Hash*> &getHashes();

                void add(Hash* hash);
            }


            /**
             * @brief Adds a new hash
             * @tparam T The hash type that extends hex::Hash
             * @param args The arguments to pass to the constructor of the hash
             */
            template<typename T, typename ... Args>
            void add(Args && ... args) {
                impl::add(new T(std::forward<Args>(args)...));
            }

        }
    }

}