STR_GAME_OPTIONS_AUTOSAVE_DROPDOWN_EVERY_6_MONTHS,

	STR_GAME_OPTIONS_AUTOSAVE_DROPDOWN_EVERY_12_MONTHS,

	INVALID_STRING_ID,

};

static const StringID _gui_zoom_dropdown[] = {

	STR_GAME_OPTIONS_GUI_ZOOM_DROPDOWN_AUTO,

	STR_GAME_OPTIONS_GUI_ZOOM_DROPDOWN_NORMAL,

	STR_GAME_OPTIONS_GUI_ZOOM_DROPDOWN_2X_ZOOM,

	STR_GAME_OPTIONS_GUI_ZOOM_DROPDOWN_4X_ZOOM,

	INVALID_STRING_ID,

};

static const StringID _font_zoom_dropdown[] = {

	STR_GAME_OPTIONS_FONT_ZOOM_DROPDOWN_AUTO,

	STR_GAME_OPTIONS_FONT_ZOOM_DROPDOWN_NORMAL,

	STR_GAME_OPTIONS_FONT_ZOOM_DROPDOWN_2X_ZOOM,

	STR_GAME_OPTIONS_FONT_ZOOM_DROPDOWN_4X_ZOOM,

	INVALID_STRING_ID,

};

static Dimension _circle_size; ///< Dimension of the circle +/- icon. This is here as not all users are within the class of the settings window.

static const void *ResolveVariableAddress(const GameSettings *settings_ptr, const SettingDesc *sd);

/**

 * Get index of the current screen resolution.

 * @return Index of the current screen resolution if it is a known resolution, _resolutions.size() otherwise.

 */

static uint GetCurrentResolutionIndex()

{

	auto it = std::find(_resolutions.begin(), _resolutions.end(), Dimension(_screen.width, _screen.height));

	return std::distance(_resolutions.begin(), it);

}

static void ShowCustCurrency();

template <class T>

static DropDownList BuildSetDropDownList(int *selected_index, bool allow_selection)

{

	int n = T::GetNumSets();

	*selected_index = T::GetIndexOfUsedSet();

	DropDownList list;

	for (int i = 0; i < n; i++) {

		list.emplace_back(new DropDownListCharStringItem(T::GetSet(i)->name, i, !allow_selection && (*selected_index != i)));

	}

	return list;

}

DropDownList BuildMusicSetDropDownList(int *selected_index)

{

	return BuildSetDropDownList<BaseMusic>(selected_index, true);

}

/** Window for displaying the textfile of a BaseSet. */

template <class TBaseSet>

struct BaseSetTextfileWindow : public TextfileWindow {

	const TBaseSet* baseset; ///< View the textfile of this BaseSet.

	StringID content_type;   ///< STR_CONTENT_TYPE_xxx for title.

	BaseSetTextfileWindow(TextfileType file_type, const TBaseSet* baseset, StringID content_type) : TextfileWindow(file_type), baseset(baseset), content_type(content_type)

	{

		const char *textfile = this->baseset->GetTextfile(file_type);

		this->LoadTextfile(textfile, BASESET_DIR);

	}

	void SetStringParameters(int widget) const override

	{

		if (widget == WID_TF_CAPTION) {

			SetDParam(0, content_type);

			SetDParamStr(1, this->baseset->name.c_str());

		}

	}

};

/**

 * Open the BaseSet version of the textfile window.

 * @param file_type The type of textfile to display.

 * @param baseset The BaseSet to use.

 * @param content_type STR_CONTENT_TYPE_xxx for title.

 */

template <class TBaseSet>

void ShowBaseSetTextfileWindow(TextfileType file_type, const TBaseSet* baseset, StringID content_type)

{

	DeleteWindowById(WC_TEXTFILE, file_type);

	new BaseSetTextfileWindow<TBaseSet>(file_type, baseset, content_type);

}

std::set<int> _refresh_rates = { 30, 60, 75, 90, 100, 120, 144, 240 };

/**

 * Add the refresh rate from the config and the refresh rates from all the monitors to

 * our list of refresh rates shown in the GUI.

 */

{

	/* Add the refresh rate as selected in the config. */

	_refresh_rates.insert(_settings_client.gui.refresh_rate);

	/* Add all the refresh rates of all monitors connected to the machine.  */

	std::vector<int> monitorRates = VideoDriver::GetInstance()->GetListOfMonitorRefreshRates();

	std::copy(monitorRates.begin(), monitorRates.end(), std::inserter(_refresh_rates, _refresh_rates.end()));

}

struct GameOptionsWindow : Window {

	GameSettings *opt;

	bool reload;

	GameOptionsWindow(WindowDesc *desc) : Window(desc)

	{

		this->opt = &GetGameSettings();

		this->reload = false;

		this->InitNested(WN_GAME_OPTIONS_GAME_OPTIONS);

		this->OnInvalidateData(0);

	}

	~GameOptionsWindow()

	{

		DeleteWindowById(WC_CUSTOM_CURRENCY, 0);

		DeleteWindowByClass(WC_TEXTFILE);

		if (this->reload) _switch_mode = SM_MENU;

	}

	/**

	 * Build the dropdown list for a specific widget.

	 * @param widget         Widget to build list for

	 * @param selected_index Currently selected item

	 * @return the built dropdown list, or nullptr if the widget has no dropdown menu.

	 */

	DropDownList BuildDropDownList(int widget, int *selected_index) const

	{

		DropDownList list;

		switch (widget) {

			case WID_GO_CURRENCY_DROPDOWN: { // Setup currencies dropdown

				*selected_index = this->opt->locale.currency;

				StringID *items = BuildCurrencyDropdown();

				uint64 disabled = _game_mode == GM_MENU ? 0LL : ~GetMaskOfAllowedCurrencies();

				/* Add non-custom currencies; sorted naturally */

				for (uint i = 0; i < CURRENCY_END; items++, i++) {

					if (i == CURRENCY_CUSTOM) continue;

					list.emplace_back(new DropDownListStringItem(*items, i, HasBit(disabled, i)));

				}

				std::sort(list.begin(), list.end(), DropDownListStringItem::NatSortFunc);

				/* Append custom currency at the end */

				list.emplace_back(new DropDownListItem(-1, false)); // separator line

				list.emplace_back(new DropDownListStringItem(STR_GAME_OPTIONS_CURRENCY_CUSTOM, CURRENCY_CUSTOM, HasBit(disabled, CURRENCY_CUSTOM)));

				break;

			}

			case WID_GO_AUTOSAVE_DROPDOWN: { // Setup autosave dropdown

				*selected_index = _settings_client.gui.autosave;

				const StringID *items = _autosave_dropdown;

				for (uint i = 0; *items != INVALID_STRING_ID; items++, i++) {

					list.emplace_back(new DropDownListStringItem(*items, i, false));

				}

				break;

			}

			case WID_GO_LANG_DROPDOWN: { // Setup interface language dropdown

				for (uint i = 0; i < _languages.size(); i++) {

					auto item = new DropDownListParamStringItem(STR_JUST_RAW_STRING, i, false);

					if (&_languages[i] == _current_language) {

						*selected_index = i;

						item->SetParamStr(0, _languages[i].own_name);

					} else {

						/* Especially with sprite-fonts, not all localized

						 * names can be rendered. So instead, we use the

						 * international names for anything but the current

						 * selected language. This avoids showing a few ????

						 * entries in the dropdown list. */

						item->SetParamStr(0, _languages[i].name);

					}

					list.emplace_back(item);

				}

				std::sort(list.begin(), list.end(), DropDownListStringItem::NatSortFunc);

				break;

			}

			case WID_GO_RESOLUTION_DROPDOWN: // Setup resolution dropdown

				if (_resolutions.empty()) break;

				*selected_index = GetCurrentResolutionIndex();

				for (uint i = 0; i < _resolutions.size(); i++) {

					auto item = new DropDownListParamStringItem(STR_GAME_OPTIONS_RESOLUTION_ITEM, i, false);

					item->SetParam(0, _resolutions[i].width);

					item->SetParam(1, _resolutions[i].height);

					list.emplace_back(item);

				}

				break;

			case WID_GO_REFRESH_RATE_DROPDOWN: // Setup refresh rate dropdown

				for (auto it = _refresh_rates.begin(); it != _refresh_rates.end(); it++) {

					auto i = std::distance(_refresh_rates.begin(), it);

					if (*it == _settings_client.gui.refresh_rate) *selected_index = i;

					auto item = new DropDownListParamStringItem(STR_GAME_OPTIONS_REFRESH_RATE_ITEM, i, false);

					item->SetParam(0, *it);

					list.emplace_back(item);

				}

				break;

			case WID_GO_GUI_ZOOM_DROPDOWN: {

				*selected_index = _gui_zoom_cfg != ZOOM_LVL_CFG_AUTO ? ZOOM_LVL_OUT_4X - _gui_zoom + 1 : 0;

				const StringID *items = _gui_zoom_dropdown;

				for (int i = 0; *items != INVALID_STRING_ID; items++, i++) {

					list.emplace_back(new DropDownListStringItem(*items, i, i != 0 && _settings_client.gui.zoom_min > ZOOM_LVL_OUT_4X - i + 1));