#include <components/lua_ui/content.hpp>
#include <components/lua_ui/widgetlist.hpp>
#include <components/lua_ui/element.hpp>

#include "context.hpp"
#include "actions.hpp"
#include "luamanagerimp.hpp"

namespace MWLua
{
    namespace
    {
        std::set<LuaUi::Element*> allElements;

        class UiAction final : public Action
        {
            public:
                enum Type
                {
                    CREATE = 0,
                    UPDATE,
                    DESTROY,
                };

                UiAction(Type type, std::shared_ptr<LuaUi::Element> element, LuaUtil::LuaState* state)
                    : Action(state)
                    , mType{ type }
                    , mElement{ std::move(element) }
                {}

                void apply(WorldView&) const override
                {
                    try {
                        switch (mType)
                        {
                            case CREATE:
                                mElement->create();
                                break;
                            case UPDATE:
                                mElement->update();
                                break;
                            case DESTROY:
                                mElement->destroy();
                                break;
                        }
                    }
                    catch (std::exception& e)
                    {
                        // prevent any actions on a potentially corrupted widget
                        mElement->mRoot = nullptr;
                        throw;
                    }
                }

                std::string toString() const override
                {
                    std::string result;
                    switch (mType)
                    {
                        case CREATE:
                            result += "Create";
                            break;
                        case UPDATE:
                            result += "Update";
                            break;
                        case DESTROY:
                            result += "Destroy";
                            break;
                    }
                    result += " UI";
                    return result;
                }

            private:
                Type mType;
                std::shared_ptr<LuaUi::Element> mElement;
        };

        // Lua arrays index from 1
        inline size_t fromLuaIndex(size_t i) { return i - 1; }
        inline size_t toLuaIndex(size_t i) { return i + 1; }
    }

    sol::table initUserInterfacePackage(const Context& context)
    {
        auto uiContent = context.mLua->sol().new_usertype<LuaUi::Content>("UiContent");
        uiContent[sol::meta_function::length] = [](const LuaUi::Content& content)
        {
            return content.size();
        };
        uiContent[sol::meta_function::index] = sol::overload(
            [](const LuaUi::Content& content, size_t index)
            {
                return content.at(fromLuaIndex(index));
            },
            [](const LuaUi::Content& content, std::string_view name)
            {
                return content.at(name);
            });
        uiContent[sol::meta_function::new_index] = sol::overload(
            [](LuaUi::Content& content, size_t index, const sol::table& table)
            {
                content.assign(fromLuaIndex(index), table);
            },
            [](LuaUi::Content& content, size_t index, sol::nil_t nil)
            {
                content.remove(fromLuaIndex(index));
            },
            [](LuaUi::Content& content, std::string_view name, const sol::table& table)
            {
                content.assign(name, table);
            },
            [](LuaUi::Content& content, std::string_view name, sol::nil_t nil)
            {
                content.remove(name);
            });
        uiContent["insert"] = [](LuaUi::Content& content, size_t index, const sol::table& table)
        {
            content.insert(fromLuaIndex(index), table);
        };
        uiContent["add"] = [](LuaUi::Content& content, const sol::table& table)
        {
            content.insert(content.size(), table);
        };
        uiContent["indexOf"] = [](LuaUi::Content& content, const sol::table& table) -> sol::optional<size_t>
        {
            size_t index = content.indexOf(table);
            if (index < content.size())
                return toLuaIndex(index);
            else
                return sol::nullopt;
        };

        auto element = context.mLua->sol().new_usertype<LuaUi::Element>("Element");
        element["layout"] = sol::property(
            [](LuaUi::Element& element)
            {
                return element.mLayout;
            },
            [](LuaUi::Element& element, const sol::table& layout)
            {
                element.mLayout = layout;
            }
        );
        element["update"] = [context](const std::shared_ptr<LuaUi::Element>& element)
        {
            if (element->mDestroy || element->mUpdate)
                return;
            element->mUpdate = true;
            context.mLuaManager->addAction(std::make_unique<UiAction>(UiAction::UPDATE, element, context.mLua));
        };
        element["destroy"] = [context](const std::shared_ptr<LuaUi::Element>& element)
        {
            if (element->mDestroy)
                return;
            allElements.erase(element.get());
            element->mDestroy = true;
            context.mLuaManager->addAction(std::make_unique<UiAction>(UiAction::DESTROY, element, context.mLua));
        };

        sol::table api = context.mLua->newTable();
        api["showMessage"] = [luaManager=context.mLuaManager](std::string_view message)
        {
            luaManager->addUIMessage(message);
        };
        api["content"] = [](const sol::table& table)
        {
            return LuaUi::Content(table);
        };
        api["create"] = [context](const sol::table& layout)
        {
            auto element = std::make_shared<LuaUi::Element>(layout);
            allElements.emplace(element.get());
            context.mLuaManager->addAction(std::make_unique<UiAction>(UiAction::CREATE, element, context.mLua));
            return element;
        };

        sol::table typeTable = context.mLua->newTable();
        for (const auto& it : LuaUi::widgetTypeToName())
            typeTable.set(it.second, it.first);
        api["TYPE"] = LuaUtil::makeReadOnly(typeTable);

        return LuaUtil::makeReadOnly(api);
    }
    
    void clearUserInterface()
    {
        for (auto element : allElements)
            element->destroy();
        allElements.clear();
    }
}