Fix #10023: Allow negative input in text fields when needed (#10112)

[openttd-github.git] / src / settings_gui.cpp

/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file settings_gui.cpp GUI for settings. */

#include "stdafx.h"
#include "currency.h"
#include "error.h"
#include "settings_gui.h"
#include "textbuf_gui.h"
#include "command_func.h"
#include "network/network.h"
#include "town.h"
#include "settings_internal.h"
#include "strings_func.h"
#include "window_func.h"
#include "string_func.h"
#include "widgets/dropdown_type.h"
#include "widgets/dropdown_func.h"
#include "widgets/slider_func.h"
#include "highscore.h"
#include "base_media_base.h"
#include "company_base.h"
#include "company_func.h"
#include "viewport_func.h"
#include "core/geometry_func.hpp"
#include "ai/ai.hpp"
#include "blitter/factory.hpp"
#include "language.h"
#include "textfile_gui.h"
#include "stringfilter_type.h"
#include "querystring_gui.h"
#include "fontcache.h"
#include "zoom_func.h"
#include "rev.h"
#include "video/video_driver.hpp"
#include "music/music_driver.hpp"

#include <vector>
#include <iterator>

#include "safeguards.h"
#include "video/video_driver.hpp"


static const StringID _autosave_dropdown[] = {
        STR_GAME_OPTIONS_AUTOSAVE_DROPDOWN_OFF,
        STR_GAME_OPTIONS_AUTOSAVE_DROPDOWN_EVERY_1_MONTH,
        STR_GAME_OPTIONS_AUTOSAVE_DROPDOWN_EVERY_3_MONTHS,
        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 *ResolveObject(const GameSettings *settings_ptr, const IntSettingDesc *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);
                }
        }
};

/**
 * 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)
{
        CloseWindowById(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.
 */
static void AddCustomRefreshRates()
{
        /* 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;

                AddCustomRefreshRates();

                this->InitNested(WN_GAME_OPTIONS_GAME_OPTIONS);
                this->OnInvalidateData(0);
        }

        void Close() override
        {
                CloseWindowById(WC_CUSTOM_CURRENCY, 0);
                CloseWindowByClass(WC_TEXTFILE);
                if (this->reload) _switch_mode = SM_MENU;
                this->Window::Close();
        }

        /**
         * 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++) {
                                        bool hide_language = IsReleasedVersion() && !_languages[i].IsReasonablyFinished();
                                        if (hide_language) continue;
                                        bool hide_percentage = IsReleasedVersion() || _languages[i].missing < _settings_client.gui.missing_strings_threshold;
                                        auto item = new DropDownListParamStringItem(hide_percentage ? STR_JUST_RAW_STRING : STR_GAME_OPTIONS_LANGUAGE_PERCENTAGE, 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);
                                        }
                                        item->SetParam(1, (LANGUAGE_TOTAL_STRINGS - _languages[i].missing) * 100 / LANGUAGE_TOTAL_STRINGS);
                                        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));
                                }
                                break;
                        }

                        case WID_GO_FONT_ZOOM_DROPDOWN: {
                                *selected_index = _font_zoom_cfg != ZOOM_LVL_CFG_AUTO ? ZOOM_LVL_OUT_4X - _font_zoom + 1 : 0;
                                const StringID *items = _font_zoom_dropdown;
                                for (int i = 0; *items != INVALID_STRING_ID; items++, i++) {
                                        list.emplace_back(new DropDownListStringItem(*items, i, false));
                                }
                                break;
                        }

                        case WID_GO_BASE_GRF_DROPDOWN:
                                list = BuildSetDropDownList<BaseGraphics>(selected_index, (_game_mode == GM_MENU));
                                break;

                        case WID_GO_BASE_SFX_DROPDOWN:
                                list = BuildSetDropDownList<BaseSounds>(selected_index, (_game_mode == GM_MENU));
                                break;

                        case WID_GO_BASE_MUSIC_DROPDOWN:
                                list = BuildMusicSetDropDownList(selected_index);
                                break;
                }

                return list;
        }

        void SetStringParameters(int widget) const override
        {
                switch (widget) {
                        case WID_GO_CURRENCY_DROPDOWN:     SetDParam(0, _currency_specs[this->opt->locale.currency].name); break;
                        case WID_GO_AUTOSAVE_DROPDOWN:     SetDParam(0, _autosave_dropdown[_settings_client.gui.autosave]); break;
                        case WID_GO_LANG_DROPDOWN:         SetDParamStr(0, _current_language->own_name); break;
                        case WID_GO_GUI_ZOOM_DROPDOWN:     SetDParam(0, _gui_zoom_dropdown[_gui_zoom_cfg != ZOOM_LVL_CFG_AUTO ? ZOOM_LVL_OUT_4X - _gui_zoom_cfg + 1 : 0]); break;
                        case WID_GO_FONT_ZOOM_DROPDOWN:    SetDParam(0, _font_zoom_dropdown[_font_zoom_cfg != ZOOM_LVL_CFG_AUTO ? ZOOM_LVL_OUT_4X - _font_zoom_cfg + 1 : 0]); break;
                        case WID_GO_BASE_GRF_DROPDOWN:     SetDParamStr(0, BaseGraphics::GetUsedSet()->name); break;
                        case WID_GO_BASE_GRF_STATUS:       SetDParam(0, BaseGraphics::GetUsedSet()->GetNumInvalid()); break;
                        case WID_GO_BASE_SFX_DROPDOWN:     SetDParamStr(0, BaseSounds::GetUsedSet()->name); break;
                        case WID_GO_BASE_MUSIC_DROPDOWN:   SetDParamStr(0, BaseMusic::GetUsedSet()->name); break;
                        case WID_GO_BASE_MUSIC_STATUS:     SetDParam(0, BaseMusic::GetUsedSet()->GetNumInvalid()); break;
                        case WID_GO_VIDEO_DRIVER_INFO:     SetDParamStr(0, VideoDriver::GetInstance()->GetInfoString()); break;
                        case WID_GO_REFRESH_RATE_DROPDOWN: SetDParam(0, _settings_client.gui.refresh_rate); break;
                        case WID_GO_RESOLUTION_DROPDOWN: {
                                auto current_resolution = GetCurrentResolutionIndex();

                                if (current_resolution == _resolutions.size()) {
                                        SetDParam(0, STR_GAME_OPTIONS_RESOLUTION_OTHER);
                                } else {
                                        SetDParam(0, STR_GAME_OPTIONS_RESOLUTION_ITEM);
                                        SetDParam(1, _resolutions[current_resolution].width);
                                        SetDParam(2, _resolutions[current_resolution].height);
                                }
                                break;
                        }
                }
        }

        void DrawWidget(const Rect &r, int widget) const override
        {
                switch (widget) {
                        case WID_GO_BASE_GRF_DESCRIPTION:
                                SetDParamStr(0, BaseGraphics::GetUsedSet()->GetDescription(GetCurrentLanguageIsoCode()));
                                DrawStringMultiLine(r.left, r.right, r.top, UINT16_MAX, STR_BLACK_RAW_STRING);
                                break;

                        case WID_GO_BASE_SFX_DESCRIPTION:
                                SetDParamStr(0, BaseSounds::GetUsedSet()->GetDescription(GetCurrentLanguageIsoCode()));
                                DrawStringMultiLine(r.left, r.right, r.top, UINT16_MAX, STR_BLACK_RAW_STRING);
                                break;

                        case WID_GO_BASE_MUSIC_DESCRIPTION:
                                SetDParamStr(0, BaseMusic::GetUsedSet()->GetDescription(GetCurrentLanguageIsoCode()));
                                DrawStringMultiLine(r.left, r.right, r.top, UINT16_MAX, STR_BLACK_RAW_STRING);
                                break;

                        case WID_GO_BASE_SFX_VOLUME:
                                DrawVolumeSliderWidget(r, _settings_client.music.effect_vol);
                                break;

                        case WID_GO_BASE_MUSIC_VOLUME:
                                DrawVolumeSliderWidget(r, _settings_client.music.music_vol);
                                break;
                }
        }

        void UpdateWidgetSize(int widget, Dimension *size, const Dimension &padding, Dimension *fill, Dimension *resize) override
        {
                switch (widget) {
                        case WID_GO_BASE_GRF_DESCRIPTION:
                                /* Find the biggest description for the default size. */
                                for (int i = 0; i < BaseGraphics::GetNumSets(); i++) {
                                        SetDParamStr(0, BaseGraphics::GetSet(i)->GetDescription(GetCurrentLanguageIsoCode()));
                                        size->height = std::max(size->height, (uint)GetStringHeight(STR_BLACK_RAW_STRING, size->width));
                                }
                                break;

                        case WID_GO_BASE_GRF_STATUS:
                                /* Find the biggest description for the default size. */
                                for (int i = 0; i < BaseGraphics::GetNumSets(); i++) {
                                        uint invalid_files = BaseGraphics::GetSet(i)->GetNumInvalid();
                                        if (invalid_files == 0) continue;

                                        SetDParam(0, invalid_files);
                                        *size = maxdim(*size, GetStringBoundingBox(STR_GAME_OPTIONS_BASE_GRF_STATUS));
                                }
                                break;

                        case WID_GO_BASE_SFX_DESCRIPTION:
                                /* Find the biggest description for the default size. */
                                for (int i = 0; i < BaseSounds::GetNumSets(); i++) {
                                        SetDParamStr(0, BaseSounds::GetSet(i)->GetDescription(GetCurrentLanguageIsoCode()));
                                        size->height = std::max(size->height, (uint)GetStringHeight(STR_BLACK_RAW_STRING, size->width));
                                }
                                break;

                        case WID_GO_BASE_MUSIC_DESCRIPTION:
                                /* Find the biggest description for the default size. */
                                for (int i = 0; i < BaseMusic::GetNumSets(); i++) {
                                        SetDParamStr(0, BaseMusic::GetSet(i)->GetDescription(GetCurrentLanguageIsoCode()));
                                        size->height = std::max(size->height, (uint)GetStringHeight(STR_BLACK_RAW_STRING, size->width));
                                }
                                break;

                        case WID_GO_BASE_MUSIC_STATUS:
                                /* Find the biggest description for the default size. */
                                for (int i = 0; i < BaseMusic::GetNumSets(); i++) {
                                        uint invalid_files = BaseMusic::GetSet(i)->GetNumInvalid();
                                        if (invalid_files == 0) continue;

                                        SetDParam(0, invalid_files);
                                        *size = maxdim(*size, GetStringBoundingBox(STR_GAME_OPTIONS_BASE_MUSIC_STATUS));
                                }
                                break;

                        default: {
                                int selected;
                                DropDownList list = this->BuildDropDownList(widget, &selected);
                                if (!list.empty()) {
                                        /* Find the biggest item for the default size. */
                                        for (const auto &ddli : list) {
                                                Dimension string_dim;
                                                int width = ddli->Width();
                                                string_dim.width = width + padding.width;
                                                string_dim.height = ddli->Height(width) + padding.height;
                                                *size = maxdim(*size, string_dim);
                                        }
                                }
                        }
                }
        }

        void OnClick(Point pt, int widget, int click_count) override
        {
                if (widget >= WID_GO_BASE_GRF_TEXTFILE && widget < WID_GO_BASE_GRF_TEXTFILE + TFT_END) {
                        if (BaseGraphics::GetUsedSet() == nullptr) return;

                        ShowBaseSetTextfileWindow((TextfileType)(widget - WID_GO_BASE_GRF_TEXTFILE), BaseGraphics::GetUsedSet(), STR_CONTENT_TYPE_BASE_GRAPHICS);
                        return;
                }
                if (widget >= WID_GO_BASE_SFX_TEXTFILE && widget < WID_GO_BASE_SFX_TEXTFILE + TFT_END) {
                        if (BaseSounds::GetUsedSet() == nullptr) return;

                        ShowBaseSetTextfileWindow((TextfileType)(widget - WID_GO_BASE_SFX_TEXTFILE), BaseSounds::GetUsedSet(), STR_CONTENT_TYPE_BASE_SOUNDS);
                        return;
                }
                if (widget >= WID_GO_BASE_MUSIC_TEXTFILE && widget < WID_GO_BASE_MUSIC_TEXTFILE + TFT_END) {
                        if (BaseMusic::GetUsedSet() == nullptr) return;

                        ShowBaseSetTextfileWindow((TextfileType)(widget - WID_GO_BASE_MUSIC_TEXTFILE), BaseMusic::GetUsedSet(), STR_CONTENT_TYPE_BASE_MUSIC);
                        return;
                }
                switch (widget) {
                        case WID_GO_FULLSCREEN_BUTTON: // Click fullscreen on/off
                                /* try to toggle full-screen on/off */
                                if (!ToggleFullScreen(!_fullscreen)) {
                                        ShowErrorMessage(STR_ERROR_FULLSCREEN_FAILED, INVALID_STRING_ID, WL_ERROR);
                                }
                                this->SetWidgetLoweredState(WID_GO_FULLSCREEN_BUTTON, _fullscreen);
                                this->SetWidgetDirty(WID_GO_FULLSCREEN_BUTTON);
                                break;

                        case WID_GO_VIDEO_ACCEL_BUTTON:
                                _video_hw_accel = !_video_hw_accel;
                                ShowErrorMessage(STR_GAME_OPTIONS_VIDEO_ACCELERATION_RESTART, INVALID_STRING_ID, WL_INFO);
                                this->SetWidgetLoweredState(WID_GO_VIDEO_ACCEL_BUTTON, _video_hw_accel);
                                this->SetWidgetDirty(WID_GO_VIDEO_ACCEL_BUTTON);
#ifndef __APPLE__
                                this->SetWidgetDisabledState(WID_GO_VIDEO_VSYNC_BUTTON, !_video_hw_accel);
                                this->SetWidgetDirty(WID_GO_VIDEO_VSYNC_BUTTON);
#endif
                                break;

                        case WID_GO_VIDEO_VSYNC_BUTTON:
                                if (!_video_hw_accel) break;

                                _video_vsync = !_video_vsync;
                                VideoDriver::GetInstance()->ToggleVsync(_video_vsync);

                                this->SetWidgetLoweredState(WID_GO_VIDEO_VSYNC_BUTTON, _video_vsync);
                                this->SetWidgetDirty(WID_GO_VIDEO_VSYNC_BUTTON);
                                this->SetWidgetDisabledState(WID_GO_REFRESH_RATE_DROPDOWN, _video_vsync);
                                this->SetWidgetDirty(WID_GO_REFRESH_RATE_DROPDOWN);
                                break;

                        case WID_GO_BASE_SFX_VOLUME:
                        case WID_GO_BASE_MUSIC_VOLUME: {
                                byte &vol = (widget == WID_GO_BASE_MUSIC_VOLUME) ? _settings_client.music.music_vol : _settings_client.music.effect_vol;
                                if (ClickVolumeSliderWidget(this->GetWidget<NWidgetBase>(widget)->GetCurrentRect(), pt, vol)) {
                                        if (widget == WID_GO_BASE_MUSIC_VOLUME) MusicDriver::GetInstance()->SetVolume(vol);
                                        this->SetWidgetDirty(widget);
                                        SetWindowClassesDirty(WC_MUSIC_WINDOW);
                                }

                                if (click_count > 0) this->mouse_capture_widget = widget;
                                break;
                        }

                        default: {
                                int selected;
                                DropDownList list = this->BuildDropDownList(widget, &selected);
                                if (!list.empty()) {
                                        ShowDropDownList(this, std::move(list), selected, widget);
                                } else {
                                        if (widget == WID_GO_RESOLUTION_DROPDOWN) ShowErrorMessage(STR_ERROR_RESOLUTION_LIST_FAILED, INVALID_STRING_ID, WL_ERROR);
                                }
                                break;
                        }
                }
        }

        /**
         * Set the base media set.
         * @param index the index of the media set
         * @tparam T class of media set
         */
        template <class T>
        void SetMediaSet(int index)
        {
                if (_game_mode == GM_MENU) {
                        auto name = T::GetSet(index)->name;

                        T::ini_set = name;

                        T::SetSet(name);
                        this->reload = true;
                        this->InvalidateData();
                }
        }

        void OnDropdownSelect(int widget, int index) override
        {
                switch (widget) {
                        case WID_GO_CURRENCY_DROPDOWN: // Currency
                                if (index == CURRENCY_CUSTOM) ShowCustCurrency();
                                this->opt->locale.currency = index;
                                ReInitAllWindows(false);
                                break;

                        case WID_GO_AUTOSAVE_DROPDOWN: // Autosave options
                                _settings_client.gui.autosave = index;
                                this->SetDirty();
                                break;

                        case WID_GO_LANG_DROPDOWN: // Change interface language
                                ReadLanguagePack(&_languages[index]);
                                CloseWindowByClass(WC_QUERY_STRING);
                                CheckForMissingGlyphs();
                                ClearAllCachedNames();
                                UpdateAllVirtCoords();
                                CheckBlitter();
                                ReInitAllWindows(false);
                                break;

                        case WID_GO_RESOLUTION_DROPDOWN: // Change resolution
                                if ((uint)index < _resolutions.size() && ChangeResInGame(_resolutions[index].width, _resolutions[index].height)) {
                                        this->SetDirty();
                                }
                                break;

                        case WID_GO_REFRESH_RATE_DROPDOWN: {
                                _settings_client.gui.refresh_rate = *std::next(_refresh_rates.begin(), index);
                                if (_settings_client.gui.refresh_rate > 60) {
                                        /* Show warning to the user that this refresh rate might not be suitable on
                                         * larger maps with many NewGRFs and vehicles. */
                                        ShowErrorMessage(STR_GAME_OPTIONS_REFRESH_RATE_WARNING, INVALID_STRING_ID, WL_INFO);
                                }
                                break;
                        }

                        case WID_GO_GUI_ZOOM_DROPDOWN: {
                                int8 new_zoom = index > 0 ? ZOOM_LVL_OUT_4X - index + 1 : ZOOM_LVL_CFG_AUTO;
                                if (new_zoom != _gui_zoom_cfg) {
                                        GfxClearSpriteCache();
                                        _gui_zoom_cfg = new_zoom;
                                        UpdateGUIZoom();
                                        UpdateCursorSize();
                                        UpdateAllVirtCoords();
                                        FixTitleGameZoom();
                                        ReInitAllWindows(true);
                                }
                                break;
                        }

                        case WID_GO_FONT_ZOOM_DROPDOWN: {
                                int8 new_zoom = index > 0 ? ZOOM_LVL_OUT_4X - index + 1 : ZOOM_LVL_CFG_AUTO;
                                if (new_zoom != _font_zoom_cfg) {
                                        GfxClearSpriteCache();
                                        _font_zoom_cfg = new_zoom;
                                        UpdateGUIZoom();
                                        ClearFontCache();
                                        LoadStringWidthTable();
                                        UpdateAllVirtCoords();
                                        ReInitAllWindows(true);
                                }
                                break;
                        }

                        case WID_GO_BASE_GRF_DROPDOWN:
                                this->SetMediaSet<BaseGraphics>(index);
                                break;

                        case WID_GO_BASE_SFX_DROPDOWN:
                                this->SetMediaSet<BaseSounds>(index);
                                break;

                        case WID_GO_BASE_MUSIC_DROPDOWN:
                                ChangeMusicSet(index);
                                break;
                }
        }

        /**
         * Some data on this window has become invalid.
         * @param data Information about the changed data. @see GameOptionsInvalidationData
         * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
         */
        void OnInvalidateData(int data = 0, bool gui_scope = true) override
        {
                if (!gui_scope) return;
                this->SetWidgetLoweredState(WID_GO_FULLSCREEN_BUTTON, _fullscreen);
                this->SetWidgetLoweredState(WID_GO_VIDEO_ACCEL_BUTTON, _video_hw_accel);
                this->SetWidgetDisabledState(WID_GO_REFRESH_RATE_DROPDOWN, _video_vsync);

#ifndef __APPLE__
                this->SetWidgetLoweredState(WID_GO_VIDEO_VSYNC_BUTTON, _video_vsync);
                this->SetWidgetDisabledState(WID_GO_VIDEO_VSYNC_BUTTON, !_video_hw_accel);
#endif

                bool missing_files = BaseGraphics::GetUsedSet()->GetNumMissing() == 0;
                this->GetWidget<NWidgetCore>(WID_GO_BASE_GRF_STATUS)->SetDataTip(missing_files ? STR_EMPTY : STR_GAME_OPTIONS_BASE_GRF_STATUS, STR_NULL);

                for (TextfileType tft = TFT_BEGIN; tft < TFT_END; tft++) {
                        this->SetWidgetDisabledState(WID_GO_BASE_GRF_TEXTFILE + tft, BaseGraphics::GetUsedSet() == nullptr || BaseGraphics::GetUsedSet()->GetTextfile(tft) == nullptr);
                        this->SetWidgetDisabledState(WID_GO_BASE_SFX_TEXTFILE + tft, BaseSounds::GetUsedSet() == nullptr || BaseSounds::GetUsedSet()->GetTextfile(tft) == nullptr);
                        this->SetWidgetDisabledState(WID_GO_BASE_MUSIC_TEXTFILE + tft, BaseMusic::GetUsedSet() == nullptr || BaseMusic::GetUsedSet()->GetTextfile(tft) == nullptr);
                }

                missing_files = BaseMusic::GetUsedSet()->GetNumInvalid() == 0;
                this->GetWidget<NWidgetCore>(WID_GO_BASE_MUSIC_STATUS)->SetDataTip(missing_files ? STR_EMPTY : STR_GAME_OPTIONS_BASE_MUSIC_STATUS, STR_NULL);
        }
};

static const NWidgetPart _nested_game_options_widgets[] = {
        NWidget(NWID_HORIZONTAL),
                NWidget(WWT_CLOSEBOX, COLOUR_GREY),
                NWidget(WWT_CAPTION, COLOUR_GREY), SetDataTip(STR_GAME_OPTIONS_CAPTION, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS),
        EndContainer(),
        NWidget(WWT_PANEL, COLOUR_GREY, WID_GO_BACKGROUND), SetPIP(6, 6, 10),
                NWidget(NWID_HORIZONTAL), SetPIP(10, 10, 10),
                        NWidget(NWID_VERTICAL), SetPIP(0, 6, 0),
                                NWidget(WWT_FRAME, COLOUR_GREY), SetDataTip(STR_GAME_OPTIONS_AUTOSAVE_FRAME, STR_NULL),
                                        NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_GO_AUTOSAVE_DROPDOWN), SetMinimalSize(150, 12), SetDataTip(STR_BLACK_STRING, STR_GAME_OPTIONS_AUTOSAVE_DROPDOWN_TOOLTIP), SetFill(1, 0),
                                EndContainer(),
                                NWidget(WWT_FRAME, COLOUR_GREY), SetDataTip(STR_GAME_OPTIONS_GUI_ZOOM_FRAME, STR_NULL),
                                        NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_GO_GUI_ZOOM_DROPDOWN), SetMinimalSize(150, 12), SetDataTip(STR_BLACK_STRING, STR_GAME_OPTIONS_GUI_ZOOM_DROPDOWN_TOOLTIP), SetFill(1, 0),
                                EndContainer(),
                                NWidget(WWT_FRAME, COLOUR_GREY), SetDataTip(STR_GAME_OPTIONS_CURRENCY_UNITS_FRAME, STR_NULL),
                                        NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_GO_CURRENCY_DROPDOWN), SetMinimalSize(150, 12), SetDataTip(STR_BLACK_STRING, STR_GAME_OPTIONS_CURRENCY_UNITS_DROPDOWN_TOOLTIP), SetFill(1, 0),
                                EndContainer(),
                        EndContainer(),

                        NWidget(NWID_VERTICAL), SetPIP(0, 6, 0),
                                NWidget(WWT_FRAME, COLOUR_GREY), SetDataTip(STR_GAME_OPTIONS_LANGUAGE, STR_NULL),
                                        NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_GO_LANG_DROPDOWN), SetMinimalSize(150, 12), SetDataTip(STR_BLACK_RAW_STRING, STR_GAME_OPTIONS_LANGUAGE_TOOLTIP), SetFill(1, 0),
                                EndContainer(),
                                NWidget(WWT_FRAME, COLOUR_GREY), SetDataTip(STR_GAME_OPTIONS_FONT_ZOOM, STR_NULL),
                                        NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_GO_FONT_ZOOM_DROPDOWN), SetMinimalSize(150, 12), SetDataTip(STR_BLACK_STRING, STR_GAME_OPTIONS_FONT_ZOOM_DROPDOWN_TOOLTIP), SetFill(1, 0),
                                EndContainer(),
                        EndContainer(),
                EndContainer(),

                NWidget(WWT_FRAME, COLOUR_GREY), SetDataTip(STR_GAME_OPTIONS_GRAPHICS, STR_NULL), SetPadding(0, 10, 0, 10),
                        NWidget(NWID_HORIZONTAL),
                                NWidget(NWID_VERTICAL), SetPIP(0, 2, 0),
                                        NWidget(NWID_HORIZONTAL),
                                                NWidget(WWT_TEXT, COLOUR_GREY), SetMinimalSize(0, 12),SetDataTip(STR_GAME_OPTIONS_RESOLUTION, STR_NULL),
                                                NWidget(NWID_SPACER), SetMinimalSize(1, 0), SetFill(1, 0),
                                                NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_GO_RESOLUTION_DROPDOWN), SetMinimalSize(200, 12), SetDataTip(STR_BLACK_STRING, STR_GAME_OPTIONS_RESOLUTION_TOOLTIP),
                                        EndContainer(),
                                        NWidget(NWID_HORIZONTAL),
                                                NWidget(WWT_TEXT, COLOUR_GREY), SetMinimalSize(0, 12), SetDataTip(STR_GAME_OPTIONS_REFRESH_RATE, STR_NULL),
                                                NWidget(NWID_SPACER), SetMinimalSize(1, 0), SetFill(1, 0),
                                                NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_GO_REFRESH_RATE_DROPDOWN), SetMinimalSize(200, 12), SetDataTip(STR_GAME_OPTIONS_REFRESH_RATE_ITEM, STR_GAME_OPTIONS_REFRESH_RATE_TOOLTIP),
                                        EndContainer(),
                                        NWidget(NWID_HORIZONTAL),
                                                NWidget(WWT_TEXT, COLOUR_GREY), SetMinimalSize(0, 12), SetDataTip(STR_GAME_OPTIONS_FULLSCREEN, STR_NULL),
                                                NWidget(NWID_SPACER), SetMinimalSize(1, 0), SetFill(1, 0),
                                                NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_GO_FULLSCREEN_BUTTON), SetMinimalSize(21, 9), SetDataTip(STR_EMPTY, STR_GAME_OPTIONS_FULLSCREEN_TOOLTIP),
                                        EndContainer(),
                                        NWidget(NWID_HORIZONTAL),
                                                NWidget(WWT_TEXT, COLOUR_GREY), SetMinimalSize(0, 12), SetDataTip(STR_GAME_OPTIONS_VIDEO_ACCELERATION, STR_NULL),
                                                NWidget(NWID_SPACER), SetMinimalSize(1, 0), SetFill(1, 0),
                                                NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_GO_VIDEO_ACCEL_BUTTON), SetMinimalSize(21, 9), SetDataTip(STR_EMPTY, STR_GAME_OPTIONS_VIDEO_ACCELERATION_TOOLTIP),
                                        EndContainer(),
#ifndef __APPLE__
                                        NWidget(NWID_HORIZONTAL),
                                                NWidget(WWT_TEXT, COLOUR_GREY), SetMinimalSize(0, 12), SetDataTip(STR_GAME_OPTIONS_VIDEO_VSYNC, STR_NULL),
                                                NWidget(NWID_SPACER), SetMinimalSize(1, 0), SetFill(1, 0),
                                                NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_GO_VIDEO_VSYNC_BUTTON), SetMinimalSize(21, 9), SetDataTip(STR_EMPTY, STR_GAME_OPTIONS_VIDEO_VSYNC_TOOLTIP),
                                        EndContainer(),
#endif
                                        NWidget(NWID_HORIZONTAL),
                                                NWidget(WWT_TEXT, COLOUR_GREY, WID_GO_VIDEO_DRIVER_INFO), SetMinimalSize(0, 12), SetFill(1, 0), SetDataTip(STR_GAME_OPTIONS_VIDEO_DRIVER_INFO, STR_NULL),
                                        EndContainer(),
                                EndContainer(),
                        EndContainer(),
                EndContainer(),

                NWidget(WWT_FRAME, COLOUR_GREY), SetDataTip(STR_GAME_OPTIONS_BASE_GRF, STR_NULL), SetPadding(0, 10, 0, 10),
                        NWidget(NWID_HORIZONTAL), SetPIP(0, 30, 0),
                                NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_GO_BASE_GRF_DROPDOWN), SetMinimalSize(150, 12), SetDataTip(STR_BLACK_RAW_STRING, STR_GAME_OPTIONS_BASE_GRF_TOOLTIP),
                                NWidget(WWT_TEXT, COLOUR_GREY, WID_GO_BASE_GRF_STATUS), SetMinimalSize(150, 12), SetDataTip(STR_EMPTY, STR_NULL), SetFill(1, 0),
                        EndContainer(),
                        NWidget(WWT_TEXT, COLOUR_GREY, WID_GO_BASE_GRF_DESCRIPTION), SetMinimalSize(330, 0), SetDataTip(STR_EMPTY, STR_GAME_OPTIONS_BASE_GRF_DESCRIPTION_TOOLTIP), SetFill(1, 0), SetPadding(6, 0, 6, 0),
                        NWidget(NWID_HORIZONTAL, NC_EQUALSIZE), SetPIP(7, 0, 7),
                                NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_GO_BASE_GRF_TEXTFILE + TFT_README), SetFill(1, 0), SetResize(1, 0), SetDataTip(STR_TEXTFILE_VIEW_README, STR_NULL),
                                NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_GO_BASE_GRF_TEXTFILE + TFT_CHANGELOG), SetFill(1, 0), SetResize(1, 0), SetDataTip(STR_TEXTFILE_VIEW_CHANGELOG, STR_NULL),
                                NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_GO_BASE_GRF_TEXTFILE + TFT_LICENSE), SetFill(1, 0), SetResize(1, 0), SetDataTip(STR_TEXTFILE_VIEW_LICENCE, STR_NULL),
                        EndContainer(),
                EndContainer(),

                NWidget(WWT_FRAME, COLOUR_GREY), SetDataTip(STR_GAME_OPTIONS_BASE_SFX, STR_NULL), SetPadding(0, 10, 0, 10),
                        NWidget(NWID_HORIZONTAL), SetPIP(0, 30, 7),
                                NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_GO_BASE_SFX_DROPDOWN), SetMinimalSize(150, 12), SetDataTip(STR_BLACK_RAW_STRING, STR_GAME_OPTIONS_BASE_SFX_TOOLTIP),
                                NWidget(NWID_SPACER), SetMinimalSize(150, 12), SetFill(1, 0),
                                NWidget(WWT_EMPTY, COLOUR_GREY, WID_GO_BASE_SFX_VOLUME), SetMinimalSize(67, 12), SetFill(0, 0), SetDataTip(0x0, STR_MUSIC_TOOLTIP_DRAG_SLIDERS_TO_SET_MUSIC),
                        EndContainer(),
                        NWidget(WWT_TEXT, COLOUR_GREY, WID_GO_BASE_SFX_DESCRIPTION), SetMinimalSize(330, 0), SetDataTip(STR_EMPTY, STR_GAME_OPTIONS_BASE_SFX_DESCRIPTION_TOOLTIP), SetFill(1, 0), SetPadding(6, 0, 6, 0),
                        NWidget(NWID_HORIZONTAL, NC_EQUALSIZE), SetPIP(7, 0, 7),
                                NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_GO_BASE_SFX_TEXTFILE + TFT_README), SetFill(1, 0), SetResize(1, 0), SetDataTip(STR_TEXTFILE_VIEW_README, STR_NULL),
                                NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_GO_BASE_SFX_TEXTFILE + TFT_CHANGELOG), SetFill(1, 0), SetResize(1, 0), SetDataTip(STR_TEXTFILE_VIEW_CHANGELOG, STR_NULL),
                                NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_GO_BASE_SFX_TEXTFILE + TFT_LICENSE), SetFill(1, 0), SetResize(1, 0), SetDataTip(STR_TEXTFILE_VIEW_LICENCE, STR_NULL),
                        EndContainer(),
                EndContainer(),

                NWidget(WWT_FRAME, COLOUR_GREY), SetDataTip(STR_GAME_OPTIONS_BASE_MUSIC, STR_NULL), SetPadding(0, 10, 0, 10),
                        NWidget(NWID_HORIZONTAL), SetPIP(0, 30, 7),
                                NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_GO_BASE_MUSIC_DROPDOWN), SetMinimalSize(150, 12), SetDataTip(STR_BLACK_RAW_STRING, STR_GAME_OPTIONS_BASE_MUSIC_TOOLTIP),
                                NWidget(WWT_TEXT, COLOUR_GREY, WID_GO_BASE_MUSIC_STATUS), SetMinimalSize(150, 12), SetDataTip(STR_EMPTY, STR_NULL), SetFill(1, 0),
                                NWidget(WWT_EMPTY, COLOUR_GREY, WID_GO_BASE_MUSIC_VOLUME), SetMinimalSize(67, 12), SetFill(0, 0), SetDataTip(0x0, STR_MUSIC_TOOLTIP_DRAG_SLIDERS_TO_SET_MUSIC),
                        EndContainer(),
                        NWidget(WWT_TEXT, COLOUR_GREY, WID_GO_BASE_MUSIC_DESCRIPTION), SetMinimalSize(330, 0), SetDataTip(STR_EMPTY, STR_GAME_OPTIONS_BASE_MUSIC_DESCRIPTION_TOOLTIP), SetFill(1, 0), SetPadding(6, 0, 6, 0),
                        NWidget(NWID_HORIZONTAL, NC_EQUALSIZE), SetPIP(7, 0, 7),
                                NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_GO_BASE_MUSIC_TEXTFILE + TFT_README), SetFill(1, 0), SetResize(1, 0), SetDataTip(STR_TEXTFILE_VIEW_README, STR_NULL),
                                NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_GO_BASE_MUSIC_TEXTFILE + TFT_CHANGELOG), SetFill(1, 0), SetResize(1, 0), SetDataTip(STR_TEXTFILE_VIEW_CHANGELOG, STR_NULL),
                                NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_GO_BASE_MUSIC_TEXTFILE + TFT_LICENSE), SetFill(1, 0), SetResize(1, 0), SetDataTip(STR_TEXTFILE_VIEW_LICENCE, STR_NULL),
                        EndContainer(),
                EndContainer(),
        EndContainer(),
};

static WindowDesc _game_options_desc(
        WDP_CENTER, "settings_game", 0, 0,
        WC_GAME_OPTIONS, WC_NONE,
        0,
        _nested_game_options_widgets, lengthof(_nested_game_options_widgets)
);

/** Open the game options window. */
void ShowGameOptions()
{
        CloseWindowByClass(WC_GAME_OPTIONS);
        new GameOptionsWindow(&_game_options_desc);
}

static int SETTING_HEIGHT = 11;    ///< Height of a single setting in the tree view in pixels
static const int LEVEL_WIDTH = 15; ///< Indenting width of a sub-page in pixels

/**
 * Flags for #SettingEntry
 * @note The #SEF_BUTTONS_MASK matches expectations of the formal parameter 'state' of #DrawArrowButtons
 */
enum SettingEntryFlags {
        SEF_LEFT_DEPRESSED  = 0x01, ///< Of a numeric setting entry, the left button is depressed
        SEF_RIGHT_DEPRESSED = 0x02, ///< Of a numeric setting entry, the right button is depressed
        SEF_BUTTONS_MASK = (SEF_LEFT_DEPRESSED | SEF_RIGHT_DEPRESSED), ///< Bit-mask for button flags

        SEF_LAST_FIELD = 0x04, ///< This entry is the last one in a (sub-)page
        SEF_FILTERED   = 0x08, ///< Entry is hidden by the string filter
};

/** How the list of advanced settings is filtered. */
enum RestrictionMode {
        RM_BASIC,                            ///< Display settings associated to the "basic" list.
        RM_ADVANCED,                         ///< Display settings associated to the "advanced" list.
        RM_ALL,                              ///< List all settings regardless of the default/newgame/... values.
        RM_CHANGED_AGAINST_DEFAULT,          ///< Show only settings which are different compared to default values.
        RM_CHANGED_AGAINST_NEW,              ///< Show only settings which are different compared to the user's new game setting values.
        RM_END,                              ///< End for iteration.
};
DECLARE_POSTFIX_INCREMENT(RestrictionMode)

/** Filter for settings list. */
struct SettingFilter {
        StringFilter string;     ///< Filter string.
        RestrictionMode min_cat; ///< Minimum category needed to display all filtered strings (#RM_BASIC, #RM_ADVANCED, or #RM_ALL).
        bool type_hides;         ///< Whether the type hides filtered strings.
        RestrictionMode mode;    ///< Filter based on category.
        SettingType type;        ///< Filter based on type.
};

/** Data structure describing a single setting in a tab */
struct BaseSettingEntry {
        byte flags; ///< Flags of the setting entry. @see SettingEntryFlags
        byte level; ///< Nesting level of this setting entry

        BaseSettingEntry() : flags(0), level(0) {}
        virtual ~BaseSettingEntry() {}

        virtual void Init(byte level = 0);
        virtual void FoldAll() {}
        virtual void UnFoldAll() {}
        virtual void ResetAll() = 0;

        /**
         * Set whether this is the last visible entry of the parent node.
         * @param last_field Value to set
         */
        void SetLastField(bool last_field) { if (last_field) SETBITS(this->flags, SEF_LAST_FIELD); else CLRBITS(this->flags, SEF_LAST_FIELD); }

        virtual uint Length() const = 0;
        virtual void GetFoldingState(bool &all_folded, bool &all_unfolded) const {}
        virtual bool IsVisible(const BaseSettingEntry *item) const;
        virtual BaseSettingEntry *FindEntry(uint row, uint *cur_row);
        virtual uint GetMaxHelpHeight(int maxw) { return 0; }

        /**
         * Check whether an entry is hidden due to filters
         * @return true if hidden.
         */
        bool IsFiltered() const { return (this->flags & SEF_FILTERED) != 0; }

        virtual bool UpdateFilterState(SettingFilter &filter, bool force_visible) = 0;

        virtual uint Draw(GameSettings *settings_ptr, int left, int right, int y, uint first_row, uint max_row, BaseSettingEntry *selected, uint cur_row = 0, uint parent_last = 0) const;

protected:
        virtual void DrawSetting(GameSettings *settings_ptr, int left, int right, int y, bool highlight) const = 0;
};

/** Standard setting */
struct SettingEntry : BaseSettingEntry {
        const char *name;              ///< Name of the setting
        const IntSettingDesc *setting; ///< Setting description of the setting

        SettingEntry(const char *name);

        virtual void Init(byte level = 0);
        virtual void ResetAll();
        virtual uint Length() const;
        virtual uint GetMaxHelpHeight(int maxw);
        virtual bool UpdateFilterState(SettingFilter &filter, bool force_visible);

        void SetButtons(byte new_val);

        /**
         * Get the help text of a single setting.
         * @return The requested help text.
         */
        inline StringID GetHelpText() const
        {
                return this->setting->str_help;
        }

        void SetValueDParams(uint first_param, int32 value) const;

protected:
        virtual void DrawSetting(GameSettings *settings_ptr, int left, int right, int y, bool highlight) const;

private:
        bool IsVisibleByRestrictionMode(RestrictionMode mode) const;
};

/** Containers for BaseSettingEntry */
struct SettingsContainer {
        typedef std::vector<BaseSettingEntry*> EntryVector;
        EntryVector entries; ///< Settings on this page

        template<typename T>
        T *Add(T *item)
        {
                this->entries.push_back(item);
                return item;
        }

        void Init(byte level = 0);
        void ResetAll();
        void FoldAll();
        void UnFoldAll();

        uint Length() const;
        void GetFoldingState(bool &all_folded, bool &all_unfolded) const;
        bool IsVisible(const BaseSettingEntry *item) const;
        BaseSettingEntry *FindEntry(uint row, uint *cur_row);
        uint GetMaxHelpHeight(int maxw);

        bool UpdateFilterState(SettingFilter &filter, bool force_visible);

        uint Draw(GameSettings *settings_ptr, int left, int right, int y, uint first_row, uint max_row, BaseSettingEntry *selected, uint cur_row = 0, uint parent_last = 0) const;
};

/** Data structure describing one page of settings in the settings window. */
struct SettingsPage : BaseSettingEntry, SettingsContainer {
        StringID title;     ///< Title of the sub-page
        bool folded;        ///< Sub-page is folded (not visible except for its title)

        SettingsPage(StringID title);

        virtual void Init(byte level = 0);
        virtual void ResetAll();
        virtual void FoldAll();
        virtual void UnFoldAll();

        virtual uint Length() const;
        virtual void GetFoldingState(bool &all_folded, bool &all_unfolded) const;
        virtual bool IsVisible(const BaseSettingEntry *item) const;
        virtual BaseSettingEntry *FindEntry(uint row, uint *cur_row);
        virtual uint GetMaxHelpHeight(int maxw) { return SettingsContainer::GetMaxHelpHeight(maxw); }

        virtual bool UpdateFilterState(SettingFilter &filter, bool force_visible);

        virtual uint Draw(GameSettings *settings_ptr, int left, int right, int y, uint first_row, uint max_row, BaseSettingEntry *selected, uint cur_row = 0, uint parent_last = 0) const;

protected:
        virtual void DrawSetting(GameSettings *settings_ptr, int left, int right, int y, bool highlight) const;
};

/* == BaseSettingEntry methods == */

/**
 * Initialization of a setting entry
 * @param level      Page nesting level of this entry
 */
void BaseSettingEntry::Init(byte level)
{
        this->level = level;
}

/**
 * Check whether an entry is visible and not folded or filtered away.
 * Note: This does not consider the scrolling range; it might still require scrolling to make the setting really visible.
 * @param item Entry to search for.
 * @return true if entry is visible.
 */
bool BaseSettingEntry::IsVisible(const BaseSettingEntry *item) const
{
        if (this->IsFiltered()) return false;
        return this == item;
}

/**
 * Find setting entry at row \a row_num
 * @param row_num Index of entry to return
 * @param cur_row Current row number
 * @return The requested setting entry or \c nullptr if it not found (folded or filtered)
 */
BaseSettingEntry *BaseSettingEntry::FindEntry(uint row_num, uint *cur_row)
{
        if (this->IsFiltered()) return nullptr;
        if (row_num == *cur_row) return this;
        (*cur_row)++;
        return nullptr;
}

/**
 * Draw a row in the settings panel.
 *
 * The scrollbar uses rows of the page, while the page data structure is a tree of #SettingsPage and #SettingEntry objects.
 * As a result, the drawing routing traverses the tree from top to bottom, counting rows in \a cur_row until it reaches \a first_row.
 * Then it enables drawing rows while traversing until \a max_row is reached, at which point drawing is terminated.
 *
 * The \a parent_last parameter ensures that the vertical lines at the left are
 * only drawn when another entry follows, that it prevents output like
 * \verbatim
 *  |-- setting
 *  |-- (-) - Title
 *  |    |-- setting
 *  |    |-- setting
 * \endverbatim
 * The left-most vertical line is not wanted. It is prevented by setting the
 * appropriate bit in the \a parent_last parameter.
 *
 * @param settings_ptr Pointer to current values of all settings
 * @param left         Left-most position in window/panel to start drawing \a first_row
 * @param right        Right-most x position to draw strings at.
 * @param y            Upper-most position in window/panel to start drawing \a first_row
 * @param first_row    First row number to draw
 * @param max_row      Row-number to stop drawing (the row-number of the row below the last row to draw)
 * @param selected     Selected entry by the user.
 * @param cur_row      Current row number (internal variable)
 * @param parent_last  Last-field booleans of parent page level (page level \e i sets bit \e i to 1 if it is its last field)
 * @return Row number of the next row to draw
 */
uint BaseSettingEntry::Draw(GameSettings *settings_ptr, int left, int right, int y, uint first_row, uint max_row, BaseSettingEntry *selected, uint cur_row, uint parent_last) const
{
        if (this->IsFiltered()) return cur_row;
        if (cur_row >= max_row) return cur_row;

        bool rtl = _current_text_dir == TD_RTL;
        int offset = rtl ? -4 : 4;
        int level_width = rtl ? -LEVEL_WIDTH : LEVEL_WIDTH;

        int x = rtl ? right : left;
        if (cur_row >= first_row) {
                int colour = _colour_gradient[COLOUR_ORANGE][4];
                y += (cur_row - first_row) * SETTING_HEIGHT; // Compute correct y start position

                /* Draw vertical for parent nesting levels */
                for (uint lvl = 0; lvl < this->level; lvl++) {
                        if (!HasBit(parent_last, lvl)) GfxDrawLine(x + offset, y, x + offset, y + SETTING_HEIGHT - 1, colour);
                        x += level_width;
                }
                /* draw own |- prefix */
                int halfway_y = y + SETTING_HEIGHT / 2;
                int bottom_y = (flags & SEF_LAST_FIELD) ? halfway_y : y + SETTING_HEIGHT - 1;
                GfxDrawLine(x + offset, y, x + offset, bottom_y, colour);
                /* Small horizontal line from the last vertical line */
                GfxDrawLine(x + offset, halfway_y, x + level_width - offset, halfway_y, colour);
                x += level_width;

                this->DrawSetting(settings_ptr, rtl ? left : x, rtl ? x : right, y, this == selected);
        }
        cur_row++;

        return cur_row;
}

/* == SettingEntry methods == */

/**
 * Constructor for a single setting in the 'advanced settings' window
 * @param name Name of the setting in the setting table
 */
SettingEntry::SettingEntry(const char *name)
{
        this->name = name;
        this->setting = nullptr;
}

/**
 * Initialization of a setting entry
 * @param level      Page nesting level of this entry
 */
void SettingEntry::Init(byte level)
{
        BaseSettingEntry::Init(level);
        this->setting = GetSettingFromName(this->name)->AsIntSetting();
}

/* Sets the given setting entry to its default value */
void SettingEntry::ResetAll()
{
        SetSettingValue(this->setting, this->setting->def);
}

/**
 * Set the button-depressed flags (#SEF_LEFT_DEPRESSED and #SEF_RIGHT_DEPRESSED) to a specified value
 * @param new_val New value for the button flags
 * @see SettingEntryFlags
 */
void SettingEntry::SetButtons(byte new_val)
{
        assert((new_val & ~SEF_BUTTONS_MASK) == 0); // Should not touch any flags outside the buttons
        this->flags = (this->flags & ~SEF_BUTTONS_MASK) | new_val;
}

/** Return number of rows needed to display the (filtered) entry */
uint SettingEntry::Length() const
{
        return this->IsFiltered() ? 0 : 1;
}

/**
 * Get the biggest height of the help text(s), if the width is at least \a maxw. Help text gets wrapped if needed.
 * @param maxw Maximal width of a line help text.
 * @return Biggest height needed to display any help text of this node (and its descendants).
 */
uint SettingEntry::GetMaxHelpHeight(int maxw)
{
        return GetStringHeight(this->GetHelpText(), maxw);
}

/**
 * Checks whether an entry shall be made visible based on the restriction mode.
 * @param mode The current status of the restriction drop down box.
 * @return true if the entry shall be visible.
 */
bool SettingEntry::IsVisibleByRestrictionMode(RestrictionMode mode) const
{
        /* There shall not be any restriction, i.e. all settings shall be visible. */
        if (mode == RM_ALL) return true;

        const IntSettingDesc *sd = this->setting;

        if (mode == RM_BASIC) return (this->setting->cat & SC_BASIC_LIST) != 0;
        if (mode == RM_ADVANCED) return (this->setting->cat & SC_ADVANCED_LIST) != 0;

        /* Read the current value. */
        const void *object = ResolveObject(&GetGameSettings(), sd);
        int64 current_value = sd->Read(object);
        int64 filter_value;

        if (mode == RM_CHANGED_AGAINST_DEFAULT) {
                /* This entry shall only be visible, if the value deviates from its default value. */

                /* Read the default value. */
                filter_value = sd->def;
        } else {
                assert(mode == RM_CHANGED_AGAINST_NEW);
                /* This entry shall only be visible, if the value deviates from
                 * its value is used when starting a new game. */

                /* Make sure we're not comparing the new game settings against itself. */
                assert(&GetGameSettings() != &_settings_newgame);

                /* Read the new game's value. */
                filter_value = sd->Read(ResolveObject(&_settings_newgame, sd));
        }

        return current_value != filter_value;
}

/**
 * Update the filter state.
 * @param filter Filter
 * @param force_visible Whether to force all items visible, no matter what (due to filter text; not affected by restriction drop down box).
 * @return true if item remains visible
 */
bool SettingEntry::UpdateFilterState(SettingFilter &filter, bool force_visible)
{
        CLRBITS(this->flags, SEF_FILTERED);

        bool visible = true;

        const IntSettingDesc *sd = this->setting;
        if (!force_visible && !filter.string.IsEmpty()) {
                /* Process the search text filter for this item. */
                filter.string.ResetState();

                SetDParam(0, STR_EMPTY);
                filter.string.AddLine(sd->str);
                filter.string.AddLine(this->GetHelpText());

                visible = filter.string.GetState();
        }

        if (visible) {
                if (filter.type != ST_ALL && sd->GetType() != filter.type) {
                        filter.type_hides = true;
                        visible = false;
                }
                if (!this->IsVisibleByRestrictionMode(filter.mode)) {
                        while (filter.min_cat < RM_ALL && (filter.min_cat == filter.mode || !this->IsVisibleByRestrictionMode(filter.min_cat))) filter.min_cat++;
                        visible = false;
                }
        }

        if (!visible) SETBITS(this->flags, SEF_FILTERED);
        return visible;
}

static const void *ResolveObject(const GameSettings *settings_ptr, const IntSettingDesc *sd)
{
        if ((sd->flags & SF_PER_COMPANY) != 0) {
                if (Company::IsValidID(_local_company) && _game_mode != GM_MENU) {
                        return &Company::Get(_local_company)->settings;
                }
                return &_settings_client.company;
        }
        return settings_ptr;
}

/**
 * Set the DParams for drawing the value of a setting.
 * @param first_param First DParam to use
 * @param value Setting value to set params for.
 */
void SettingEntry::SetValueDParams(uint first_param, int32 value) const
{
        if (this->setting->IsBoolSetting()) {
                SetDParam(first_param++, value != 0 ? STR_CONFIG_SETTING_ON : STR_CONFIG_SETTING_OFF);
        } else {
                if ((this->setting->flags & SF_GUI_DROPDOWN) != 0) {
                        SetDParam(first_param++, this->setting->str_val - this->setting->min + value);
                } else if ((this->setting->flags & SF_GUI_NEGATIVE_IS_SPECIAL) != 0) {
                        SetDParam(first_param++, this->setting->str_val + ((value >= 0) ? 1 : 0));
                        value = abs(value);
                } else {
                        SetDParam(first_param++, this->setting->str_val + ((value == 0 && (this->setting->flags & SF_GUI_0_IS_SPECIAL) != 0) ? 1 : 0));
                }
                SetDParam(first_param++, value);
        }
}

/**
 * Function to draw setting value (button + text + current value)
 * @param settings_ptr Pointer to current values of all settings
 * @param left         Left-most position in window/panel to start drawing
 * @param right        Right-most position in window/panel to draw
 * @param y            Upper-most position in window/panel to start drawing
 * @param highlight    Highlight entry.
 */
void SettingEntry::DrawSetting(GameSettings *settings_ptr, int left, int right, int y, bool highlight) const
{
        const IntSettingDesc *sd = this->setting;
        int state = this->flags & SEF_BUTTONS_MASK;

        bool rtl = _current_text_dir == TD_RTL;
        uint buttons_left = rtl ? right + 1 - SETTING_BUTTON_WIDTH : left;
        uint text_left  = left + (rtl ? 0 : SETTING_BUTTON_WIDTH + 5);
        uint text_right = right - (rtl ? SETTING_BUTTON_WIDTH + 5 : 0);
        uint button_y = y + (SETTING_HEIGHT - SETTING_BUTTON_HEIGHT) / 2;

        /* We do not allow changes of some items when we are a client in a networkgame */
        bool editable = sd->IsEditable();

        SetDParam(0, highlight ? STR_ORANGE_STRING1_WHITE : STR_ORANGE_STRING1_LTBLUE);
        int32 value = sd->Read(ResolveObject(settings_ptr, sd));
        if (sd->IsBoolSetting()) {
                /* Draw checkbox for boolean-value either on/off */
                DrawBoolButton(buttons_left, button_y, value != 0, editable);
        } else if ((sd->flags & SF_GUI_DROPDOWN) != 0) {
                /* Draw [v] button for settings of an enum-type */
                DrawDropDownButton(buttons_left, button_y, COLOUR_YELLOW, state != 0, editable);
        } else {
                /* Draw [<][>] boxes for settings of an integer-type */
                DrawArrowButtons(buttons_left, button_y, COLOUR_YELLOW, state,
                                editable && value != (sd->flags & SF_GUI_0_IS_SPECIAL ? 0 : sd->min), editable && (uint32)value != sd->max);
        }
        this->SetValueDParams(1, value);
        DrawString(text_left, text_right, y + (SETTING_HEIGHT - FONT_HEIGHT_NORMAL) / 2, sd->str, highlight ? TC_WHITE : TC_LIGHT_BLUE);
}

/* == SettingsContainer methods == */

/**
 * Initialization of an entire setting page
 * @param level Nesting level of this page (internal variable, do not provide a value for it when calling)
 */
void SettingsContainer::Init(byte level)
{
        for (EntryVector::iterator it = this->entries.begin(); it != this->entries.end(); ++it) {
                (*it)->Init(level);
        }
}

/** Resets all settings to their default values */
void SettingsContainer::ResetAll()
{
        for (auto settings_entry : this->entries) {
                settings_entry->ResetAll();
        }
}

/** Recursively close all folds of sub-pages */
void SettingsContainer::FoldAll()
{
        for (EntryVector::iterator it = this->entries.begin(); it != this->entries.end(); ++it) {
                (*it)->FoldAll();
        }
}

/** Recursively open all folds of sub-pages */
void SettingsContainer::UnFoldAll()
{
        for (EntryVector::iterator it = this->entries.begin(); it != this->entries.end(); ++it) {
                (*it)->UnFoldAll();
        }
}

/**
 * Recursively accumulate the folding state of the tree.
 * @param[in,out] all_folded Set to false, if one entry is not folded.
 * @param[in,out] all_unfolded Set to false, if one entry is folded.
 */
void SettingsContainer::GetFoldingState(bool &all_folded, bool &all_unfolded) const
{
        for (EntryVector::const_iterator it = this->entries.begin(); it != this->entries.end(); ++it) {
                (*it)->GetFoldingState(all_folded, all_unfolded);
        }
}

/**
 * Update the filter state.
 * @param filter Filter
 * @param force_visible Whether to force all items visible, no matter what
 * @return true if item remains visible
 */
bool SettingsContainer::UpdateFilterState(SettingFilter &filter, bool force_visible)
{
        bool visible = false;
        bool first_visible = true;
        for (EntryVector::reverse_iterator it = this->entries.rbegin(); it != this->entries.rend(); ++it) {
                visible |= (*it)->UpdateFilterState(filter, force_visible);
                (*it)->SetLastField(first_visible);
                if (visible && first_visible) first_visible = false;
        }
        return visible;
}


/**
 * Check whether an entry is visible and not folded or filtered away.
 * Note: This does not consider the scrolling range; it might still require scrolling to make the setting really visible.
 * @param item Entry to search for.
 * @return true if entry is visible.
 */
bool SettingsContainer::IsVisible(const BaseSettingEntry *item) const
{
        for (EntryVector::const_iterator it = this->entries.begin(); it != this->entries.end(); ++it) {
                if ((*it)->IsVisible(item)) return true;
        }
        return false;
}

/** Return number of rows needed to display the whole page */
uint SettingsContainer::Length() const
{
        uint length = 0;
        for (EntryVector::const_iterator it = this->entries.begin(); it != this->entries.end(); ++it) {
                length += (*it)->Length();
        }
        return length;
}

/**
 * Find the setting entry at row number \a row_num
 * @param row_num Index of entry to return
 * @param cur_row Variable used for keeping track of the current row number. Should point to memory initialized to \c 0 when first called.
 * @return The requested setting entry or \c nullptr if it does not exist
 */
BaseSettingEntry *SettingsContainer::FindEntry(uint row_num, uint *cur_row)
{
        BaseSettingEntry *pe = nullptr;
        for (EntryVector::iterator it = this->entries.begin(); it != this->entries.end(); ++it) {
                pe = (*it)->FindEntry(row_num, cur_row);
                if (pe != nullptr) {
                        break;
                }
        }
        return pe;
}

/**
 * Get the biggest height of the help texts, if the width is at least \a maxw. Help text gets wrapped if needed.
 * @param maxw Maximal width of a line help text.
 * @return Biggest height needed to display any help text of this (sub-)tree.
 */
uint SettingsContainer::GetMaxHelpHeight(int maxw)
{
        uint biggest = 0;
        for (EntryVector::const_iterator it = this->entries.begin(); it != this->entries.end(); ++it) {
                biggest = std::max(biggest, (*it)->GetMaxHelpHeight(maxw));
        }
        return biggest;
}


/**
 * Draw a row in the settings panel.
 *
 * @param settings_ptr Pointer to current values of all settings
 * @param left         Left-most position in window/panel to start drawing \a first_row
 * @param right        Right-most x position to draw strings at.
 * @param y            Upper-most position in window/panel to start drawing \a first_row
 * @param first_row    First row number to draw
 * @param max_row      Row-number to stop drawing (the row-number of the row below the last row to draw)
 * @param selected     Selected entry by the user.
 * @param cur_row      Current row number (internal variable)
 * @param parent_last  Last-field booleans of parent page level (page level \e i sets bit \e i to 1 if it is its last field)
 * @return Row number of the next row to draw
 */
uint SettingsContainer::Draw(GameSettings *settings_ptr, int left, int right, int y, uint first_row, uint max_row, BaseSettingEntry *selected, uint cur_row, uint parent_last) const
{
        for (EntryVector::const_iterator it = this->entries.begin(); it != this->entries.end(); ++it) {
                cur_row = (*it)->Draw(settings_ptr, left, right, y, first_row, max_row, selected, cur_row, parent_last);
                if (cur_row >= max_row) {
                        break;
                }
        }
        return cur_row;
}

/* == SettingsPage methods == */

/**
 * Constructor for a sub-page in the 'advanced settings' window
 * @param title Title of the sub-page
 */
SettingsPage::SettingsPage(StringID title)
{
        this->title = title;
        this->folded = true;
}

/**
 * Initialization of an entire setting page
 * @param level Nesting level of this page (internal variable, do not provide a value for it when calling)
 */
void SettingsPage::Init(byte level)
{
        BaseSettingEntry::Init(level);
        SettingsContainer::Init(level + 1);
}

/** Resets all settings to their default values */
void SettingsPage::ResetAll()
{
        for (auto settings_entry : this->entries) {
                settings_entry->ResetAll();
        }
}

/** Recursively close all (filtered) folds of sub-pages */
void SettingsPage::FoldAll()
{
        if (this->IsFiltered()) return;
        this->folded = true;

        SettingsContainer::FoldAll();
}

/** Recursively open all (filtered) folds of sub-pages */
void SettingsPage::UnFoldAll()
{
        if (this->IsFiltered()) return;
        this->folded = false;

        SettingsContainer::UnFoldAll();
}

/**
 * Recursively accumulate the folding state of the (filtered) tree.
 * @param[in,out] all_folded Set to false, if one entry is not folded.
 * @param[in,out] all_unfolded Set to false, if one entry is folded.
 */
void SettingsPage::GetFoldingState(bool &all_folded, bool &all_unfolded) const
{
        if (this->IsFiltered()) return;

        if (this->folded) {
                all_unfolded = false;
        } else {
                all_folded = false;
        }

        SettingsContainer::GetFoldingState(all_folded, all_unfolded);
}

/**
 * Update the filter state.
 * @param filter Filter
 * @param force_visible Whether to force all items visible, no matter what (due to filter text; not affected by restriction drop down box).
 * @return true if item remains visible
 */
bool SettingsPage::UpdateFilterState(SettingFilter &filter, bool force_visible)
{
        if (!force_visible && !filter.string.IsEmpty()) {
                filter.string.ResetState();
                filter.string.AddLine(this->title);
                force_visible = filter.string.GetState();
        }

        bool visible = SettingsContainer::UpdateFilterState(filter, force_visible);
        if (visible) {
                CLRBITS(this->flags, SEF_FILTERED);
        } else {
                SETBITS(this->flags, SEF_FILTERED);
        }
        return visible;
}

/**
 * Check whether an entry is visible and not folded or filtered away.
 * Note: This does not consider the scrolling range; it might still require scrolling to make the setting really visible.
 * @param item Entry to search for.
 * @return true if entry is visible.
 */
bool SettingsPage::IsVisible(const BaseSettingEntry *item) const
{
        if (this->IsFiltered()) return false;
        if (this == item) return true;
        if (this->folded) return false;

        return SettingsContainer::IsVisible(item);
}

/** Return number of rows needed to display the (filtered) entry */
uint SettingsPage::Length() const
{
        if (this->IsFiltered()) return 0;
        if (this->folded) return 1; // Only displaying the title

        return 1 + SettingsContainer::Length();
}

/**
 * Find setting entry at row \a row_num
 * @param row_num Index of entry to return
 * @param cur_row Current row number
 * @return The requested setting entry or \c nullptr if it not found (folded or filtered)
 */
BaseSettingEntry *SettingsPage::FindEntry(uint row_num, uint *cur_row)
{
        if (this->IsFiltered()) return nullptr;
        if (row_num == *cur_row) return this;
        (*cur_row)++;
        if (this->folded) return nullptr;

        return SettingsContainer::FindEntry(row_num, cur_row);
}

/**
 * Draw a row in the settings panel.
 *
 * @param settings_ptr Pointer to current values of all settings
 * @param left         Left-most position in window/panel to start drawing \a first_row
 * @param right        Right-most x position to draw strings at.
 * @param y            Upper-most position in window/panel to start drawing \a first_row
 * @param first_row    First row number to draw
 * @param max_row      Row-number to stop drawing (the row-number of the row below the last row to draw)
 * @param selected     Selected entry by the user.
 * @param cur_row      Current row number (internal variable)
 * @param parent_last  Last-field booleans of parent page level (page level \e i sets bit \e i to 1 if it is its last field)
 * @return Row number of the next row to draw
 */
uint SettingsPage::Draw(GameSettings *settings_ptr, int left, int right, int y, uint first_row, uint max_row, BaseSettingEntry *selected, uint cur_row, uint parent_last) const
{
        if (this->IsFiltered()) return cur_row;
        if (cur_row >= max_row) return cur_row;

        cur_row = BaseSettingEntry::Draw(settings_ptr, left, right, y, first_row, max_row, selected, cur_row, parent_last);

        if (!this->folded) {
                if (this->flags & SEF_LAST_FIELD) {
                        assert(this->level < 8 * sizeof(parent_last));
                        SetBit(parent_last, this->level); // Add own last-field state
                }

                cur_row = SettingsContainer::Draw(settings_ptr, left, right, y, first_row, max_row, selected, cur_row, parent_last);
        }

        return cur_row;
}

/**
 * Function to draw setting value (button + text + current value)
 * @param settings_ptr Pointer to current values of all settings
 * @param left         Left-most position in window/panel to start drawing
 * @param right        Right-most position in window/panel to draw
 * @param y            Upper-most position in window/panel to start drawing
 * @param highlight    Highlight entry.
 */
void SettingsPage::DrawSetting(GameSettings *settings_ptr, int left, int right, int y, bool highlight) const
{
        bool rtl = _current_text_dir == TD_RTL;
        DrawSprite((this->folded ? SPR_CIRCLE_FOLDED : SPR_CIRCLE_UNFOLDED), PAL_NONE, rtl ? right - _circle_size.width : left, y + (SETTING_HEIGHT - _circle_size.height) / 2);
        DrawString(rtl ? left : left + _circle_size.width + 2, rtl ? right - _circle_size.width - 2 : right, y + (SETTING_HEIGHT - FONT_HEIGHT_NORMAL) / 2, this->title);
}

/** Construct settings tree */
static SettingsContainer &GetSettingsTree()
{
        static SettingsContainer *main = nullptr;

        if (main == nullptr)
        {
                /* Build up the dynamic settings-array only once per OpenTTD session */
                main = new SettingsContainer();

                SettingsPage *localisation = main->Add(new SettingsPage(STR_CONFIG_SETTING_LOCALISATION));
                {
                        localisation->Add(new SettingEntry("locale.units_velocity"));
                        localisation->Add(new SettingEntry("locale.units_power"));
                        localisation->Add(new SettingEntry("locale.units_weight"));
                        localisation->Add(new SettingEntry("locale.units_volume"));
                        localisation->Add(new SettingEntry("locale.units_force"));
                        localisation->Add(new SettingEntry("locale.units_height"));
                        localisation->Add(new SettingEntry("gui.date_format_in_default_names"));
                }

                SettingsPage *graphics = main->Add(new SettingsPage(STR_CONFIG_SETTING_GRAPHICS));
                {
                        graphics->Add(new SettingEntry("gui.zoom_min"));
                        graphics->Add(new SettingEntry("gui.zoom_max"));
                        graphics->Add(new SettingEntry("gui.sprite_zoom_min"));
                        graphics->Add(new SettingEntry("gui.smallmap_land_colour"));
                        graphics->Add(new SettingEntry("gui.linkgraph_colours"));
                        graphics->Add(new SettingEntry("gui.graph_line_thickness"));
                }

                SettingsPage *sound = main->Add(new SettingsPage(STR_CONFIG_SETTING_SOUND));
                {
                        sound->Add(new SettingEntry("sound.click_beep"));
                        sound->Add(new SettingEntry("sound.confirm"));
                        sound->Add(new SettingEntry("sound.news_ticker"));
                        sound->Add(new SettingEntry("sound.news_full"));
                        sound->Add(new SettingEntry("sound.new_year"));
                        sound->Add(new SettingEntry("sound.disaster"));
                        sound->Add(new SettingEntry("sound.vehicle"));
                        sound->Add(new SettingEntry("sound.ambient"));
                }

                SettingsPage *interface = main->Add(new SettingsPage(STR_CONFIG_SETTING_INTERFACE));
                {
                        SettingsPage *general = interface->Add(new SettingsPage(STR_CONFIG_SETTING_INTERFACE_GENERAL));
                        {
                                general->Add(new SettingEntry("gui.osk_activation"));
                                general->Add(new SettingEntry("gui.hover_delay_ms"));
                                general->Add(new SettingEntry("gui.errmsg_duration"));
                                general->Add(new SettingEntry("gui.window_snap_radius"));
                                general->Add(new SettingEntry("gui.window_soft_limit"));
                                general->Add(new SettingEntry("gui.right_mouse_wnd_close"));
                        }

                        SettingsPage *viewports = interface->Add(new SettingsPage(STR_CONFIG_SETTING_INTERFACE_VIEWPORTS));
                        {
                                viewports->Add(new SettingEntry("gui.auto_scrolling"));
                                viewports->Add(new SettingEntry("gui.scroll_mode"));
                                viewports->Add(new SettingEntry("gui.smooth_scroll"));
                                /* While the horizontal scrollwheel scrolling is written as general code, only
                                 *  the cocoa (OSX) driver generates input for it.
                                 *  Since it's also able to completely disable the scrollwheel will we display it on all platforms anyway */
                                viewports->Add(new SettingEntry("gui.scrollwheel_scrolling"));
                                viewports->Add(new SettingEntry("gui.scrollwheel_multiplier"));
#ifdef __APPLE__
                                /* We might need to emulate a right mouse button on mac */
                                viewports->Add(new SettingEntry("gui.right_mouse_btn_emulation"));
#endif
                                viewports->Add(new SettingEntry("gui.population_in_label"));
                                viewports->Add(new SettingEntry("gui.liveries"));
                                viewports->Add(new SettingEntry("construction.train_signal_side"));
                                viewports->Add(new SettingEntry("gui.measure_tooltip"));
                                viewports->Add(new SettingEntry("gui.loading_indicators"));
                                viewports->Add(new SettingEntry("gui.show_track_reservation"));
                        }

                        SettingsPage *construction = interface->Add(new SettingsPage(STR_CONFIG_SETTING_INTERFACE_CONSTRUCTION));
                        {
                                construction->Add(new SettingEntry("gui.link_terraform_toolbar"));
                                construction->Add(new SettingEntry("gui.persistent_buildingtools"));
                                construction->Add(new SettingEntry("gui.quick_goto"));
                                construction->Add(new SettingEntry("gui.default_rail_type"));
                        }

                        interface->Add(new SettingEntry("gui.fast_forward_speed_limit"));
                        interface->Add(new SettingEntry("gui.autosave"));
                        interface->Add(new SettingEntry("gui.toolbar_pos"));
                        interface->Add(new SettingEntry("gui.statusbar_pos"));
                        interface->Add(new SettingEntry("gui.prefer_teamchat"));
                        interface->Add(new SettingEntry("gui.advanced_vehicle_list"));
                        interface->Add(new SettingEntry("gui.timetable_in_ticks"));
                        interface->Add(new SettingEntry("gui.timetable_arrival_departure"));
                        interface->Add(new SettingEntry("gui.show_newgrf_name"));
                }

                SettingsPage *advisors = main->Add(new SettingsPage(STR_CONFIG_SETTING_ADVISORS));
                {
                        advisors->Add(new SettingEntry("gui.coloured_news_year"));
                        advisors->Add(new SettingEntry("news_display.general"));
                        advisors->Add(new SettingEntry("news_display.new_vehicles"));
                        advisors->Add(new SettingEntry("news_display.accident"));
                        advisors->Add(new SettingEntry("news_display.accident_other"));
                        advisors->Add(new SettingEntry("news_display.company_info"));
                        advisors->Add(new SettingEntry("news_display.acceptance"));
                        advisors->Add(new SettingEntry("news_display.arrival_player"));
                        advisors->Add(new SettingEntry("news_display.arrival_other"));
                        advisors->Add(new SettingEntry("news_display.advice"));
                        advisors->Add(new SettingEntry("gui.order_review_system"));
                        advisors->Add(new SettingEntry("gui.vehicle_income_warn"));
                        advisors->Add(new SettingEntry("gui.lost_vehicle_warn"));
                        advisors->Add(new SettingEntry("gui.show_finances"));
                        advisors->Add(new SettingEntry("news_display.economy"));
                        advisors->Add(new SettingEntry("news_display.subsidies"));
                        advisors->Add(new SettingEntry("news_display.open"));
                        advisors->Add(new SettingEntry("news_display.close"));
                        advisors->Add(new SettingEntry("news_display.production_player"));
                        advisors->Add(new SettingEntry("news_display.production_other"));
                        advisors->Add(new SettingEntry("news_display.production_nobody"));
                }

                SettingsPage *company = main->Add(new SettingsPage(STR_CONFIG_SETTING_COMPANY));
                {
                        company->Add(new SettingEntry("gui.semaphore_build_before"));
                        company->Add(new SettingEntry("gui.cycle_signal_types"));
                        company->Add(new SettingEntry("gui.signal_gui_mode"));
                        company->Add(new SettingEntry("gui.drag_signals_fixed_distance"));
                        company->Add(new SettingEntry("gui.auto_remove_signals"));
                        company->Add(new SettingEntry("gui.new_nonstop"));
                        company->Add(new SettingEntry("gui.stop_location"));
                        company->Add(new SettingEntry("gui.starting_colour"));
                        company->Add(new SettingEntry("company.engine_renew"));
                        company->Add(new SettingEntry("company.engine_renew_months"));
                        company->Add(new SettingEntry("company.engine_renew_money"));
                        company->Add(new SettingEntry("vehicle.servint_ispercent"));
                        company->Add(new SettingEntry("vehicle.servint_trains"));
                        company->Add(new SettingEntry("vehicle.servint_roadveh"));
                        company->Add(new SettingEntry("vehicle.servint_ships"));
                        company->Add(new SettingEntry("vehicle.servint_aircraft"));
                }

                SettingsPage *accounting = main->Add(new SettingsPage(STR_CONFIG_SETTING_ACCOUNTING));
                {
                        accounting->Add(new SettingEntry("economy.inflation"));
                        accounting->Add(new SettingEntry("difficulty.initial_interest"));
                        accounting->Add(new SettingEntry("difficulty.max_loan"));
                        accounting->Add(new SettingEntry("difficulty.subsidy_multiplier"));
                        accounting->Add(new SettingEntry("difficulty.subsidy_duration"));
                        accounting->Add(new SettingEntry("economy.feeder_payment_share"));
                        accounting->Add(new SettingEntry("economy.infrastructure_maintenance"));
                        accounting->Add(new SettingEntry("difficulty.vehicle_costs"));
                        accounting->Add(new SettingEntry("difficulty.construction_cost"));
                }

                SettingsPage *vehicles = main->Add(new SettingsPage(STR_CONFIG_SETTING_VEHICLES));
                {
                        SettingsPage *physics = vehicles->Add(new SettingsPage(STR_CONFIG_SETTING_VEHICLES_PHYSICS));
                        {
                                physics->Add(new SettingEntry("vehicle.train_acceleration_model"));
                                physics->Add(new SettingEntry("vehicle.train_slope_steepness"));
                                physics->Add(new SettingEntry("vehicle.wagon_speed_limits"));
                                physics->Add(new SettingEntry("vehicle.freight_trains"));
                                physics->Add(new SettingEntry("vehicle.roadveh_acceleration_model"));
                                physics->Add(new SettingEntry("vehicle.roadveh_slope_steepness"));
                                physics->Add(new SettingEntry("vehicle.smoke_amount"));
                                physics->Add(new SettingEntry("vehicle.plane_speed"));
                        }

                        SettingsPage *routing = vehicles->Add(new SettingsPage(STR_CONFIG_SETTING_VEHICLES_ROUTING));
                        {
                                routing->Add(new SettingEntry("pf.pathfinder_for_trains"));
                                routing->Add(new SettingEntry("difficulty.line_reverse_mode"));
                                routing->Add(new SettingEntry("pf.reverse_at_signals"));
                                routing->Add(new SettingEntry("pf.forbid_90_deg"));
                                routing->Add(new SettingEntry("pf.pathfinder_for_roadvehs"));
                                routing->Add(new SettingEntry("pf.pathfinder_for_ships"));
                        }

                        vehicles->Add(new SettingEntry("order.no_servicing_if_no_breakdowns"));
                        vehicles->Add(new SettingEntry("order.serviceathelipad"));
                }

                SettingsPage *limitations = main->Add(new SettingsPage(STR_CONFIG_SETTING_LIMITATIONS));
                {
                        limitations->Add(new SettingEntry("construction.command_pause_level"));
                        limitations->Add(new SettingEntry("construction.autoslope"));
                        limitations->Add(new SettingEntry("construction.extra_dynamite"));
                        limitations->Add(new SettingEntry("construction.map_height_limit"));
                        limitations->Add(new SettingEntry("construction.max_bridge_length"));
                        limitations->Add(new SettingEntry("construction.max_bridge_height"));
                        limitations->Add(new SettingEntry("construction.max_tunnel_length"));
                        limitations->Add(new SettingEntry("station.never_expire_airports"));
                        limitations->Add(new SettingEntry("vehicle.never_expire_vehicles"));
                        limitations->Add(new SettingEntry("vehicle.max_trains"));
                        limitations->Add(new SettingEntry("vehicle.max_roadveh"));
                        limitations->Add(new SettingEntry("vehicle.max_aircraft"));
                        limitations->Add(new SettingEntry("vehicle.max_ships"));
                        limitations->Add(new SettingEntry("vehicle.max_train_length"));
                        limitations->Add(new SettingEntry("station.station_spread"));
                        limitations->Add(new SettingEntry("station.distant_join_stations"));
                        limitations->Add(new SettingEntry("construction.road_stop_on_town_road"));
                        limitations->Add(new SettingEntry("construction.road_stop_on_competitor_road"));
                        limitations->Add(new SettingEntry("vehicle.disable_elrails"));
                }

                SettingsPage *disasters = main->Add(new SettingsPage(STR_CONFIG_SETTING_ACCIDENTS));
                {
                        disasters->Add(new SettingEntry("difficulty.disasters"));
                        disasters->Add(new SettingEntry("difficulty.economy"));
                        disasters->Add(new SettingEntry("difficulty.vehicle_breakdowns"));
                        disasters->Add(new SettingEntry("vehicle.plane_crashes"));
                }

                SettingsPage *genworld = main->Add(new SettingsPage(STR_CONFIG_SETTING_GENWORLD));
                {
                        genworld->Add(new SettingEntry("game_creation.landscape"));
                        genworld->Add(new SettingEntry("game_creation.land_generator"));
                        genworld->Add(new SettingEntry("difficulty.terrain_type"));
                        genworld->Add(new SettingEntry("game_creation.tgen_smoothness"));
                        genworld->Add(new SettingEntry("game_creation.variety"));
                        genworld->Add(new SettingEntry("game_creation.snow_coverage"));
                        genworld->Add(new SettingEntry("game_creation.snow_line_height"));
                        genworld->Add(new SettingEntry("game_creation.desert_coverage"));
                        genworld->Add(new SettingEntry("game_creation.amount_of_rivers"));
                        genworld->Add(new SettingEntry("game_creation.tree_placer"));
                        genworld->Add(new SettingEntry("vehicle.road_side"));
                        genworld->Add(new SettingEntry("economy.larger_towns"));
                        genworld->Add(new SettingEntry("economy.initial_city_size"));
                        genworld->Add(new SettingEntry("economy.town_layout"));
                        genworld->Add(new SettingEntry("difficulty.industry_density"));
                        genworld->Add(new SettingEntry("gui.pause_on_newgame"));
                        genworld->Add(new SettingEntry("game_creation.ending_year"));
                }

                SettingsPage *environment = main->Add(new SettingsPage(STR_CONFIG_SETTING_ENVIRONMENT));
                {
                        SettingsPage *authorities = environment->Add(new SettingsPage(STR_CONFIG_SETTING_ENVIRONMENT_AUTHORITIES));
                        {
                                authorities->Add(new SettingEntry("difficulty.town_council_tolerance"));
                                authorities->Add(new SettingEntry("economy.bribe"));
                                authorities->Add(new SettingEntry("economy.exclusive_rights"));
                                authorities->Add(new SettingEntry("economy.fund_roads"));
                                authorities->Add(new SettingEntry("economy.fund_buildings"));
                                authorities->Add(new SettingEntry("economy.station_noise_level"));
                        }

                        SettingsPage *towns = environment->Add(new SettingsPage(STR_CONFIG_SETTING_ENVIRONMENT_TOWNS));
                        {
                                towns->Add(new SettingEntry("economy.town_growth_rate"));
                                towns->Add(new SettingEntry("economy.allow_town_roads"));
                                towns->Add(new SettingEntry("economy.allow_town_level_crossings"));
                                towns->Add(new SettingEntry("economy.found_town"));
                                towns->Add(new SettingEntry("economy.town_cargogen_mode"));
                        }

                        SettingsPage *industries = environment->Add(new SettingsPage(STR_CONFIG_SETTING_ENVIRONMENT_INDUSTRIES));
                        {
                                industries->Add(new SettingEntry("construction.raw_industry_construction"));
                                industries->Add(new SettingEntry("construction.industry_platform"));
                                industries->Add(new SettingEntry("economy.multiple_industry_per_town"));
                                industries->Add(new SettingEntry("game_creation.oil_refinery_limit"));
                                industries->Add(new SettingEntry("economy.type"));
                                industries->Add(new SettingEntry("station.serve_neutral_industries"));
                        }

                        SettingsPage *cdist = environment->Add(new SettingsPage(STR_CONFIG_SETTING_ENVIRONMENT_CARGODIST));
                        {
                                cdist->Add(new SettingEntry("linkgraph.recalc_time"));
                                cdist->Add(new SettingEntry("linkgraph.recalc_interval"));
                                cdist->Add(new SettingEntry("linkgraph.distribution_pax"));
                                cdist->Add(new SettingEntry("linkgraph.distribution_mail"));
                                cdist->Add(new SettingEntry("linkgraph.distribution_armoured"));
                                cdist->Add(new SettingEntry("linkgraph.distribution_default"));
                                cdist->Add(new SettingEntry("linkgraph.accuracy"));
                                cdist->Add(new SettingEntry("linkgraph.demand_distance"));
                                cdist->Add(new SettingEntry("linkgraph.demand_size"));
                                cdist->Add(new SettingEntry("linkgraph.short_path_saturation"));
                        }

                        environment->Add(new SettingEntry("station.modified_catchment"));
                        environment->Add(new SettingEntry("construction.extra_tree_placement"));
                }

                SettingsPage *ai = main->Add(new SettingsPage(STR_CONFIG_SETTING_AI));
                {
                        SettingsPage *npc = ai->Add(new SettingsPage(STR_CONFIG_SETTING_AI_NPC));
                        {
                                npc->Add(new SettingEntry("script.settings_profile"));
                                npc->Add(new SettingEntry("script.script_max_opcode_till_suspend"));
                                npc->Add(new SettingEntry("script.script_max_memory_megabytes"));
                                npc->Add(new SettingEntry("difficulty.competitor_speed"));
                                npc->Add(new SettingEntry("ai.ai_in_multiplayer"));
                                npc->Add(new SettingEntry("ai.ai_disable_veh_train"));
                                npc->Add(new SettingEntry("ai.ai_disable_veh_roadveh"));
                                npc->Add(new SettingEntry("ai.ai_disable_veh_aircraft"));
                                npc->Add(new SettingEntry("ai.ai_disable_veh_ship"));
                        }

                        ai->Add(new SettingEntry("economy.give_money"));
                        ai->Add(new SettingEntry("economy.allow_shares"));
                        ai->Add(new SettingEntry("economy.min_years_for_shares"));
                }

                SettingsPage *network = main->Add(new SettingsPage(STR_CONFIG_SETTING_NETWORK));
                {
                        network->Add(new SettingEntry("network.use_relay_service"));
                }

                main->Init();
        }
        return *main;
}

static const StringID _game_settings_restrict_dropdown[] = {
        STR_CONFIG_SETTING_RESTRICT_BASIC,                            // RM_BASIC
        STR_CONFIG_SETTING_RESTRICT_ADVANCED,                         // RM_ADVANCED
        STR_CONFIG_SETTING_RESTRICT_ALL,                              // RM_ALL
        STR_CONFIG_SETTING_RESTRICT_CHANGED_AGAINST_DEFAULT,          // RM_CHANGED_AGAINST_DEFAULT
        STR_CONFIG_SETTING_RESTRICT_CHANGED_AGAINST_NEW,              // RM_CHANGED_AGAINST_NEW
};
static_assert(lengthof(_game_settings_restrict_dropdown) == RM_END);

/** Warnings about hidden search results. */
enum WarnHiddenResult {
        WHR_NONE,          ///< Nothing was filtering matches away.
        WHR_CATEGORY,      ///< Category setting filtered matches away.
        WHR_TYPE,          ///< Type setting filtered matches away.
        WHR_CATEGORY_TYPE, ///< Both category and type settings filtered matches away.
};

/**
 * Callback function for the reset all settings button
 * @param w Window which is calling this callback
 * @param confirmed boolean value, true when yes was clicked, false otherwise
 */
static void ResetAllSettingsConfirmationCallback(Window *w, bool confirmed)
{
        if (confirmed) {
                GetSettingsTree().ResetAll();
                GetSettingsTree().FoldAll();
                w->InvalidateData();
        }
}

/** Window to edit settings of the game. */
struct GameSettingsWindow : Window {
        static const int SETTINGTREE_LEFT_OFFSET   = 5; ///< Position of left edge of setting values
        static const int SETTINGTREE_RIGHT_OFFSET  = 5; ///< Position of right edge of setting values
        static const int SETTINGTREE_TOP_OFFSET    = 5; ///< Position of top edge of setting values
        static const int SETTINGTREE_BOTTOM_OFFSET = 5; ///< Position of bottom edge of setting values

        static GameSettings *settings_ptr; ///< Pointer to the game settings being displayed and modified.

        SettingEntry *valuewindow_entry;   ///< If non-nullptr, pointer to setting for which a value-entering window has been opened.
        SettingEntry *clicked_entry;       ///< If non-nullptr, pointer to a clicked numeric setting (with a depressed left or right button).
        SettingEntry *last_clicked;        ///< If non-nullptr, pointer to the last clicked setting.
        SettingEntry *valuedropdown_entry; ///< If non-nullptr, pointer to the value for which a dropdown window is currently opened.
        bool closing_dropdown;             ///< True, if the dropdown list is currently closing.

        SettingFilter filter;              ///< Filter for the list.
        QueryString filter_editbox;        ///< Filter editbox;
        bool manually_changed_folding;     ///< Whether the user expanded/collapsed something manually.
        WarnHiddenResult warn_missing;     ///< Whether and how to warn about missing search results.
        int warn_lines;                    ///< Number of lines used for warning about missing search results.

        Scrollbar *vscroll;

        GameSettingsWindow(WindowDesc *desc) : Window(desc), filter_editbox(50)
        {
                this->warn_missing = WHR_NONE;
                this->warn_lines = 0;
                this->filter.mode = (RestrictionMode)_settings_client.gui.settings_restriction_mode;
                this->filter.min_cat = RM_ALL;
                this->filter.type = ST_ALL;
                this->filter.type_hides = false;
                this->settings_ptr = &GetGameSettings();

                _circle_size = maxdim(GetSpriteSize(SPR_CIRCLE_FOLDED), GetSpriteSize(SPR_CIRCLE_UNFOLDED));
                GetSettingsTree().FoldAll(); // Close all sub-pages

                this->valuewindow_entry = nullptr; // No setting entry for which a entry window is opened
                this->clicked_entry = nullptr; // No numeric setting buttons are depressed
                this->last_clicked = nullptr;
                this->valuedropdown_entry = nullptr;
                this->closing_dropdown = false;
                this->manually_changed_folding = false;

                this->CreateNestedTree();
                this->vscroll = this->GetScrollbar(WID_GS_SCROLLBAR);
                this->FinishInitNested(WN_GAME_OPTIONS_GAME_SETTINGS);

                this->querystrings[WID_GS_FILTER] = &this->filter_editbox;
                this->filter_editbox.cancel_button = QueryString::ACTION_CLEAR;
                this->SetFocusedWidget(WID_GS_FILTER);

                this->InvalidateData();
        }

        void UpdateWidgetSize(int widget, Dimension *size, const Dimension &padding, Dimension *fill, Dimension *resize) override
        {
                switch (widget) {
                        case WID_GS_OPTIONSPANEL:
                                resize->height = SETTING_HEIGHT = std::max({(int)_circle_size.height, SETTING_BUTTON_HEIGHT, FONT_HEIGHT_NORMAL}) + 1;
                                resize->width  = 1;

                                size->height = 5 * resize->height + SETTINGTREE_TOP_OFFSET + SETTINGTREE_BOTTOM_OFFSET;
                                break;

                        case WID_GS_HELP_TEXT: {
                                static const StringID setting_types[] = {
                                        STR_CONFIG_SETTING_TYPE_CLIENT,
                                        STR_CONFIG_SETTING_TYPE_COMPANY_MENU, STR_CONFIG_SETTING_TYPE_COMPANY_INGAME,
                                        STR_CONFIG_SETTING_TYPE_GAME_MENU, STR_CONFIG_SETTING_TYPE_GAME_INGAME,
                                };
                                for (uint i = 0; i < lengthof(setting_types); i++) {
                                        SetDParam(0, setting_types[i]);
                                        size->width = std::max(size->width, GetStringBoundingBox(STR_CONFIG_SETTING_TYPE).width);
                                }
                                size->height = 2 * FONT_HEIGHT_NORMAL + WD_PAR_VSEP_NORMAL +
                                                std::max(size->height, GetSettingsTree().GetMaxHelpHeight(size->width));
                                break;
                        }

                        case WID_GS_RESTRICT_CATEGORY:
                        case WID_GS_RESTRICT_TYPE:
                                size->width = std::max(GetStringBoundingBox(STR_CONFIG_SETTING_RESTRICT_CATEGORY).width, GetStringBoundingBox(STR_CONFIG_SETTING_RESTRICT_TYPE).width);
                                break;

                        default:
                                break;
                }
        }

        void OnPaint() override
        {
                if (this->closing_dropdown) {
                        this->closing_dropdown = false;
                        assert(this->valuedropdown_entry != nullptr);
                        this->valuedropdown_entry->SetButtons(0);
                        this->valuedropdown_entry = nullptr;
                }

                /* Reserve the correct number of lines for the 'some search results are hidden' notice in the central settings display panel. */
                const NWidgetBase *panel = this->GetWidget<NWidgetBase>(WID_GS_OPTIONSPANEL);
                StringID warn_str = STR_CONFIG_SETTING_CATEGORY_HIDES - 1 + this->warn_missing;
                int new_warn_lines;
                if (this->warn_missing == WHR_NONE) {
                        new_warn_lines = 0;
                } else {
                        SetDParam(0, _game_settings_restrict_dropdown[this->filter.min_cat]);
                        new_warn_lines = GetStringLineCount(warn_str, panel->current_x);
                }
                if (this->warn_lines != new_warn_lines) {
                        this->vscroll->SetCount(this->vscroll->GetCount() - this->warn_lines + new_warn_lines);
                        this->warn_lines = new_warn_lines;
                }

                this->DrawWidgets();

                /* Draw the 'some search results are hidden' notice. */
                if (this->warn_missing != WHR_NONE) {
                        const int left = panel->pos_x;
                        const int right = left + panel->current_x - 1;
                        const int top = panel->pos_y + WD_FRAMETEXT_TOP + (SETTING_HEIGHT - FONT_HEIGHT_NORMAL) * this->warn_lines / 2;
                        SetDParam(0, _game_settings_restrict_dropdown[this->filter.min_cat]);
                        if (this->warn_lines == 1) {
                                /* If the warning fits at one line, center it. */
                                DrawString(left + WD_FRAMETEXT_LEFT, right - WD_FRAMETEXT_RIGHT, top, warn_str, TC_FROMSTRING, SA_HOR_CENTER);
                        } else {
                                DrawStringMultiLine(left + WD_FRAMERECT_LEFT, right - WD_FRAMERECT_RIGHT, top, INT32_MAX, warn_str, TC_FROMSTRING, SA_HOR_CENTER);
                        }
                }
        }

        void SetStringParameters(int widget) const override
        {
                switch (widget) {
                        case WID_GS_RESTRICT_DROPDOWN:
                                SetDParam(0, _game_settings_restrict_dropdown[this->filter.mode]);
                                break;

                        case WID_GS_TYPE_DROPDOWN:
                                switch (this->filter.type) {
                                        case ST_GAME:    SetDParam(0, _game_mode == GM_MENU ? STR_CONFIG_SETTING_TYPE_DROPDOWN_GAME_MENU : STR_CONFIG_SETTING_TYPE_DROPDOWN_GAME_INGAME); break;
                                        case ST_COMPANY: SetDParam(0, _game_mode == GM_MENU ? STR_CONFIG_SETTING_TYPE_DROPDOWN_COMPANY_MENU : STR_CONFIG_SETTING_TYPE_DROPDOWN_COMPANY_INGAME); break;
                                        case ST_CLIENT:  SetDParam(0, STR_CONFIG_SETTING_TYPE_DROPDOWN_CLIENT); break;
                                        default:         SetDParam(0, STR_CONFIG_SETTING_TYPE_DROPDOWN_ALL); break;
                                }
                                break;
                }
        }

        DropDownList BuildDropDownList(int widget) const
        {
                DropDownList list;
                switch (widget) {
                        case WID_GS_RESTRICT_DROPDOWN:
                                for (int mode = 0; mode != RM_END; mode++) {
                                        /* If we are in adv. settings screen for the new game's settings,
                                         * we don't want to allow comparing with new game's settings. */
                                        bool disabled = mode == RM_CHANGED_AGAINST_NEW && settings_ptr == &_settings_newgame;

                                        list.emplace_back(new DropDownListStringItem(_game_settings_restrict_dropdown[mode], mode, disabled));
                                }
                                break;

                        case WID_GS_TYPE_DROPDOWN:
                                list.emplace_back(new DropDownListStringItem(STR_CONFIG_SETTING_TYPE_DROPDOWN_ALL, ST_ALL, false));
                                list.emplace_back(new DropDownListStringItem(_game_mode == GM_MENU ? STR_CONFIG_SETTING_TYPE_DROPDOWN_GAME_MENU : STR_CONFIG_SETTING_TYPE_DROPDOWN_GAME_INGAME, ST_GAME, false));
                                list.emplace_back(new DropDownListStringItem(_game_mode == GM_MENU ? STR_CONFIG_SETTING_TYPE_DROPDOWN_COMPANY_MENU : STR_CONFIG_SETTING_TYPE_DROPDOWN_COMPANY_INGAME, ST_COMPANY, false));
                                list.emplace_back(new DropDownListStringItem(STR_CONFIG_SETTING_TYPE_DROPDOWN_CLIENT, ST_CLIENT, false));
                                break;
                }
                return list;
        }

        void DrawWidget(const Rect &r, int widget) const override
        {
                switch (widget) {
                        case WID_GS_OPTIONSPANEL: {
                                int top_pos = r.top + SETTINGTREE_TOP_OFFSET + 1 + this->warn_lines * SETTING_HEIGHT;
                                uint last_row = this->vscroll->GetPosition() + this->vscroll->GetCapacity() - this->warn_lines;
                                int next_row = GetSettingsTree().Draw(settings_ptr, r.left + SETTINGTREE_LEFT_OFFSET, r.right - SETTINGTREE_RIGHT_OFFSET, top_pos,
                                                this->vscroll->GetPosition(), last_row, this->last_clicked);
                                if (next_row == 0) DrawString(r.left + SETTINGTREE_LEFT_OFFSET, r.right - SETTINGTREE_RIGHT_OFFSET, top_pos, STR_CONFIG_SETTINGS_NONE);
                                break;
                        }

                        case WID_GS_HELP_TEXT:
                                if (this->last_clicked != nullptr) {
                                        const IntSettingDesc *sd = this->last_clicked->setting;

                                        int y = r.top;
                                        switch (sd->GetType()) {
                                                case ST_COMPANY: SetDParam(0, _game_mode == GM_MENU ? STR_CONFIG_SETTING_TYPE_COMPANY_MENU : STR_CONFIG_SETTING_TYPE_COMPANY_INGAME); break;
                                                case ST_CLIENT:  SetDParam(0, STR_CONFIG_SETTING_TYPE_CLIENT); break;
                                                case ST_GAME:    SetDParam(0, _game_mode == GM_MENU ? STR_CONFIG_SETTING_TYPE_GAME_MENU : STR_CONFIG_SETTING_TYPE_GAME_INGAME); break;
                                                default: NOT_REACHED();
                                        }
                                        DrawString(r.left, r.right, y, STR_CONFIG_SETTING_TYPE);
                                        y += FONT_HEIGHT_NORMAL;

                                        this->last_clicked->SetValueDParams(0, sd->def);
                                        DrawString(r.left, r.right, y, STR_CONFIG_SETTING_DEFAULT_VALUE);
                                        y += FONT_HEIGHT_NORMAL + WD_PAR_VSEP_NORMAL;

                                        DrawStringMultiLine(r.left, r.right, y, r.bottom, this->last_clicked->GetHelpText(), TC_WHITE);
                                }
                                break;

                        default:
                                break;
                }
        }

        /**
         * Set the entry that should have its help text displayed, and mark the window dirty so it gets repainted.
         * @param pe Setting to display help text of, use \c nullptr to stop displaying help of the currently displayed setting.
         */
        void SetDisplayedHelpText(SettingEntry *pe)
        {
                if (this->last_clicked != pe) this->SetDirty();
                this->last_clicked = pe;
        }

        void OnClick(Point pt, int widget, int click_count) override
        {
                switch (widget) {
                        case WID_GS_EXPAND_ALL:
                                this->manually_changed_folding = true;
                                GetSettingsTree().UnFoldAll();
                                this->InvalidateData();
                                break;

                        case WID_GS_COLLAPSE_ALL:
                                this->manually_changed_folding = true;
                                GetSettingsTree().FoldAll();
                                this->InvalidateData();
                                break;

                        case WID_GS_RESET_ALL:
                                ShowQuery(
                                        STR_CONFIG_SETTING_RESET_ALL_CONFIRMATION_DIALOG_CAPTION,
                                        STR_CONFIG_SETTING_RESET_ALL_CONFIRMATION_DIALOG_TEXT,
                                        this,
                                        ResetAllSettingsConfirmationCallback
                                );
                                break;

                        case WID_GS_RESTRICT_DROPDOWN: {
                                DropDownList list = this->BuildDropDownList(widget);
                                if (!list.empty()) {
                                        ShowDropDownList(this, std::move(list), this->filter.mode, widget);
                                }
                                break;
                        }

                        case WID_GS_TYPE_DROPDOWN: {
                                DropDownList list = this->BuildDropDownList(widget);
                                if (!list.empty()) {
                                        ShowDropDownList(this, std::move(list), this->filter.type, widget);
                                }
                                break;
                        }
                }

                if (widget != WID_GS_OPTIONSPANEL) return;

                uint btn = this->vscroll->GetScrolledRowFromWidget(pt.y, this, WID_GS_OPTIONSPANEL, SETTINGTREE_TOP_OFFSET);
                if (btn == INT_MAX || (int)btn < this->warn_lines) return;
                btn -= this->warn_lines;

                uint cur_row = 0;
                BaseSettingEntry *clicked_entry = GetSettingsTree().FindEntry(btn, &cur_row);

                if (clicked_entry == nullptr) return;  // Clicked below the last setting of the page

                int x = (_current_text_dir == TD_RTL ? this->width - 1 - pt.x : pt.x) - SETTINGTREE_LEFT_OFFSET - (clicked_entry->level + 1) * LEVEL_WIDTH;  // Shift x coordinate
                if (x < 0) return;  // Clicked left of the entry

                SettingsPage *clicked_page = dynamic_cast<SettingsPage*>(clicked_entry);
                if (clicked_page != nullptr) {
                        this->SetDisplayedHelpText(nullptr);
                        clicked_page->folded = !clicked_page->folded; // Flip 'folded'-ness of the sub-page

                        this->manually_changed_folding = true;

                        this->InvalidateData();
                        return;
                }

                SettingEntry *pe = dynamic_cast<SettingEntry*>(clicked_entry);
                assert(pe != nullptr);
                const IntSettingDesc *sd = pe->setting;

                /* return if action is only active in network, or only settable by server */
                if (!sd->IsEditable()) {
                        this->SetDisplayedHelpText(pe);
                        return;
                }

                int32 value = sd->Read(ResolveObject(settings_ptr, sd));

                /* clicked on the icon on the left side. Either scroller, bool on/off or dropdown */
                if (x < SETTING_BUTTON_WIDTH && (sd->flags & SF_GUI_DROPDOWN)) {
                        this->SetDisplayedHelpText(pe);

                        if (this->valuedropdown_entry == pe) {
                                /* unclick the dropdown */
                                HideDropDownMenu(this);
                                this->closing_dropdown = false;
                                this->valuedropdown_entry->SetButtons(0);
                                this->valuedropdown_entry = nullptr;
                        } else {
                                if (this->valuedropdown_entry != nullptr) this->valuedropdown_entry->SetButtons(0);
                                this->closing_dropdown = false;

                                const NWidgetBase *wid = this->GetWidget<NWidgetBase>(WID_GS_OPTIONSPANEL);
                                int rel_y = (pt.y - (int)wid->pos_y - SETTINGTREE_TOP_OFFSET) % wid->resize_y;

                                Rect wi_rect;
                                wi_rect.left = pt.x - (_current_text_dir == TD_RTL ? SETTING_BUTTON_WIDTH - 1 - x : x);
                                wi_rect.right = wi_rect.left + SETTING_BUTTON_WIDTH - 1;
                                wi_rect.top = pt.y - rel_y + (SETTING_HEIGHT - SETTING_BUTTON_HEIGHT) / 2;
                                wi_rect.bottom = wi_rect.top + SETTING_BUTTON_HEIGHT - 1;

                                /* For dropdowns we also have to check the y position thoroughly, the mouse may not above the just opening dropdown */
                                if (pt.y >= wi_rect.top && pt.y <= wi_rect.bottom) {
                                        this->valuedropdown_entry = pe;
                                        this->valuedropdown_entry->SetButtons(SEF_LEFT_DEPRESSED);

                                        DropDownList list;
                                        for (int i = sd->min; i <= (int)sd->max; i++) {
                                                list.emplace_back(new DropDownListStringItem(sd->str_val + i - sd->min, i, false));
                                        }

                                        ShowDropDownListAt(this, std::move(list), value, -1, wi_rect, COLOUR_ORANGE, true);
                                }
                        }
                        this->SetDirty();
                } else if (x < SETTING_BUTTON_WIDTH) {
                        this->SetDisplayedHelpText(pe);
                        int32 oldvalue = value;

                        if (sd->IsBoolSetting()) {
                                value ^= 1;
                        } else {
                                /* Add a dynamic step-size to the scroller. In a maximum of
                                 * 50-steps you should be able to get from min to max,
                                 * unless specified otherwise in the 'interval' variable
                                 * of the current setting. */
                                uint32 step = (sd->interval == 0) ? ((sd->max - sd->min) / 50) : sd->interval;
                                if (step == 0) step = 1;

                                /* don't allow too fast scrolling */
                                if ((this->flags & WF_TIMEOUT) && this->timeout_timer > 1) {
                                        _left_button_clicked = false;
                                        return;
                                }

                                /* Increase or decrease the value and clamp it to extremes */
                                if (x >= SETTING_BUTTON_WIDTH / 2) {
                                        value += step;
                                        if (sd->min < 0) {
                                                assert((int32)sd->max >= 0);
                                                if (value > (int32)sd->max) value = (int32)sd->max;
                                        } else {
                                                if ((uint32)value > sd->max) value = (int32)sd->max;
                                        }
                                        if (value < sd->min) value = sd->min; // skip between "disabled" and minimum
                                } else {
                                        value -= step;
                                        if (value < sd->min) value = (sd->flags & SF_GUI_0_IS_SPECIAL) ? 0 : sd->min;
                                }

                                /* Set up scroller timeout for numeric values */
                                if (value != oldvalue) {
                                        if (this->clicked_entry != nullptr) { // Release previous buttons if any
                                                this->clicked_entry->SetButtons(0);
                                        }
                                        this->clicked_entry = pe;
                                        this->clicked_entry->SetButtons((x >= SETTING_BUTTON_WIDTH / 2) != (_current_text_dir == TD_RTL) ? SEF_RIGHT_DEPRESSED : SEF_LEFT_DEPRESSED);
                                        this->SetTimeout();
                                        _left_button_clicked = false;
                                }
                        }

                        if (value != oldvalue) {
                                SetSettingValue(sd, value);
                                this->SetDirty();
                        }
                } else {
                        /* Only open editbox if clicked for the second time, and only for types where it is sensible for. */
                        if (this->last_clicked == pe && !sd->IsBoolSetting() && !(sd->flags & SF_GUI_DROPDOWN)) {
                                int64 value64 = value;
                                /* Show the correct currency-translated value */
                                if (sd->flags & SF_GUI_CURRENCY) value64 *= _currency->rate;

                                CharSetFilter charset_filter = CS_NUMERAL; //default, only numeric input allowed
                                if (sd->min < 0) charset_filter = CS_NUMERAL_SIGNED; // special case, also allow '-' sign for negative input

                                this->valuewindow_entry = pe;
                                SetDParam(0, value64);
                                /* Limit string length to 14 so that MAX_INT32 * max currency rate doesn't exceed MAX_INT64. */
                                ShowQueryString(STR_JUST_INT, STR_CONFIG_SETTING_QUERY_CAPTION, 15, this, charset_filter, QSF_ENABLE_DEFAULT);
                        }
                        this->SetDisplayedHelpText(pe);
                }
        }

        void OnTimeout() override
        {
                if (this->clicked_entry != nullptr) { // On timeout, release any depressed buttons
                        this->clicked_entry->SetButtons(0);
                        this->clicked_entry = nullptr;
                        this->SetDirty();
                }
        }

        void OnQueryTextFinished(char *str) override
        {
                /* The user pressed cancel */
                if (str == nullptr) return;

                assert(this->valuewindow_entry != nullptr);
                const IntSettingDesc *sd = this->valuewindow_entry->setting;

                int32 value;
                if (!StrEmpty(str)) {
                        long long llvalue = atoll(str);

                        /* Save the correct currency-translated value */
                        if (sd->flags & SF_GUI_CURRENCY) llvalue /= _currency->rate;

                        value = (int32)ClampToI32(llvalue);
                } else {
                        value = sd->def;
                }

                SetSettingValue(this->valuewindow_entry->setting, value);
                this->SetDirty();
        }

        void OnDropdownSelect(int widget, int index) override
        {
                switch (widget) {
                        case WID_GS_RESTRICT_DROPDOWN:
                                this->filter.mode = (RestrictionMode)index;
                                if (this->filter.mode == RM_CHANGED_AGAINST_DEFAULT ||
                                                this->filter.mode == RM_CHANGED_AGAINST_NEW) {

                                        if (!this->manually_changed_folding) {
                                                /* Expand all when selecting 'changes'. Update the filter state first, in case it becomes less restrictive in some cases. */
                                                GetSettingsTree().UpdateFilterState(this->filter, false);
                                                GetSettingsTree().UnFoldAll();
                                        }
                                } else {
                                        /* Non-'changes' filter. Save as default. */
                                        _settings_client.gui.settings_restriction_mode = this->filter.mode;
                                }
                                this->InvalidateData();
                                break;

                        case WID_GS_TYPE_DROPDOWN:
                                this->filter.type = (SettingType)index;
                                this->InvalidateData();
                                break;

                        default:
                                if (widget < 0) {
                                        /* Deal with drop down boxes on the panel. */
                                        assert(this->valuedropdown_entry != nullptr);
                                        const IntSettingDesc *sd = this->valuedropdown_entry->setting;
                                        assert(sd->flags & SF_GUI_DROPDOWN);

                                        SetSettingValue(sd, index);
                                        this->SetDirty();
                                }
                                break;
                }
        }

        void OnDropdownClose(Point pt, int widget, int index, bool instant_close) override
        {
                if (widget >= 0) {
                        /* Normally the default implementation of OnDropdownClose() takes care of
                         * a few things. We want that behaviour here too, but only for
                         * "normal" dropdown boxes. The special dropdown boxes added for every
                         * setting that needs one can't have this call. */
                        Window::OnDropdownClose(pt, widget, index, instant_close);
                } else {
                        /* We cannot raise the dropdown button just yet. OnClick needs some hint, whether
                         * the same dropdown button was clicked again, and then not open the dropdown again.
                         * So, we only remember that it was closed, and process it on the next OnPaint, which is
                         * after OnClick. */
                        assert(this->valuedropdown_entry != nullptr);
                        this->closing_dropdown = true;
                        this->SetDirty();
                }
        }

        void OnInvalidateData(int data = 0, bool gui_scope = true) override
        {
                if (!gui_scope) return;

                /* Update which settings are to be visible. */
                RestrictionMode min_level = (this->filter.mode <= RM_ALL) ? this->filter.mode : RM_BASIC;
                this->filter.min_cat = min_level;
                this->filter.type_hides = false;
                GetSettingsTree().UpdateFilterState(this->filter, false);

                if (this->filter.string.IsEmpty()) {
                        this->warn_missing = WHR_NONE;
                } else if (min_level < this->filter.min_cat) {
                        this->warn_missing = this->filter.type_hides ? WHR_CATEGORY_TYPE : WHR_CATEGORY;
                } else {
                        this->warn_missing = this->filter.type_hides ? WHR_TYPE : WHR_NONE;
                }
                this->vscroll->SetCount(GetSettingsTree().Length() + this->warn_lines);

                if (this->last_clicked != nullptr && !GetSettingsTree().IsVisible(this->last_clicked)) {
                        this->SetDisplayedHelpText(nullptr);
                }

                bool all_folded = true;
                bool all_unfolded = true;
                GetSettingsTree().GetFoldingState(all_folded, all_unfolded);
                this->SetWidgetDisabledState(WID_GS_EXPAND_ALL, all_unfolded);
                this->SetWidgetDisabledState(WID_GS_COLLAPSE_ALL, all_folded);
        }

        void OnEditboxChanged(int wid) override
        {
                if (wid == WID_GS_FILTER) {
                        this->filter.string.SetFilterTerm(this->filter_editbox.text.buf);
                        if (!this->filter.string.IsEmpty() && !this->manually_changed_folding) {
                                /* User never expanded/collapsed single pages and entered a filter term.
                                 * Expand everything, to save weird expand clicks, */
                                GetSettingsTree().UnFoldAll();
                        }
                        this->InvalidateData();
                }
        }

        void OnResize() override
        {
                this->vscroll->SetCapacityFromWidget(this, WID_GS_OPTIONSPANEL, SETTINGTREE_TOP_OFFSET + SETTINGTREE_BOTTOM_OFFSET);
        }
};

GameSettings *GameSettingsWindow::settings_ptr = nullptr;

static const NWidgetPart _nested_settings_selection_widgets[] = {
        NWidget(NWID_HORIZONTAL),
                NWidget(WWT_CLOSEBOX, COLOUR_MAUVE),
                NWidget(WWT_CAPTION, COLOUR_MAUVE), SetDataTip(STR_CONFIG_SETTING_TREE_CAPTION, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS),
                NWidget(WWT_DEFSIZEBOX, COLOUR_MAUVE),
        EndContainer(),
        NWidget(WWT_PANEL, COLOUR_MAUVE),
                NWidget(NWID_VERTICAL), SetPIP(WD_TEXTPANEL_TOP, WD_PAR_VSEP_NORMAL, WD_TEXTPANEL_BOTTOM),
                        NWidget(NWID_HORIZONTAL), SetPIP(WD_FRAMETEXT_LEFT, WD_FRAMETEXT_RIGHT, WD_FRAMETEXT_RIGHT),
                                NWidget(WWT_TEXT, COLOUR_MAUVE, WID_GS_RESTRICT_CATEGORY), SetDataTip(STR_CONFIG_SETTING_RESTRICT_CATEGORY, STR_NULL),
                                NWidget(WWT_DROPDOWN, COLOUR_MAUVE, WID_GS_RESTRICT_DROPDOWN), SetMinimalSize(100, 12), SetDataTip(STR_BLACK_STRING, STR_CONFIG_SETTING_RESTRICT_DROPDOWN_HELPTEXT), SetFill(1, 0), SetResize(1, 0),
                        EndContainer(),
                        NWidget(NWID_HORIZONTAL), SetPIP(WD_FRAMETEXT_LEFT, WD_FRAMETEXT_RIGHT, WD_FRAMETEXT_RIGHT),
                                NWidget(WWT_TEXT, COLOUR_MAUVE, WID_GS_RESTRICT_TYPE), SetDataTip(STR_CONFIG_SETTING_RESTRICT_TYPE, STR_NULL),
                                NWidget(WWT_DROPDOWN, COLOUR_MAUVE, WID_GS_TYPE_DROPDOWN), SetMinimalSize(100, 12), SetDataTip(STR_BLACK_STRING, STR_CONFIG_SETTING_TYPE_DROPDOWN_HELPTEXT), SetFill(1, 0), SetResize(1, 0),
                        EndContainer(),
                        NWidget(NWID_HORIZONTAL), SetPIP(WD_FRAMETEXT_LEFT, WD_FRAMETEXT_RIGHT, WD_FRAMETEXT_RIGHT),
                                NWidget(WWT_TEXT, COLOUR_MAUVE), SetFill(0, 1), SetDataTip(STR_CONFIG_SETTING_FILTER_TITLE, STR_NULL),
                                NWidget(WWT_EDITBOX, COLOUR_MAUVE, WID_GS_FILTER), SetMinimalSize(50, 12), SetDataTip(STR_LIST_FILTER_OSKTITLE, STR_LIST_FILTER_TOOLTIP), SetFill(1, 0), SetResize(1, 0),
                        EndContainer(),
                EndContainer(),
        EndContainer(),
        NWidget(NWID_HORIZONTAL),
                NWidget(WWT_PANEL, COLOUR_MAUVE, WID_GS_OPTIONSPANEL), SetMinimalSize(400, 174), SetScrollbar(WID_GS_SCROLLBAR), EndContainer(),
                NWidget(NWID_VSCROLLBAR, COLOUR_MAUVE, WID_GS_SCROLLBAR),
        EndContainer(),
        NWidget(WWT_PANEL, COLOUR_MAUVE),
                NWidget(WWT_EMPTY, INVALID_COLOUR, WID_GS_HELP_TEXT), SetMinimalSize(300, 25), SetFill(1, 1), SetResize(1, 0),
                                SetPadding(WD_FRAMETEXT_TOP, WD_FRAMETEXT_RIGHT, WD_FRAMETEXT_BOTTOM, WD_FRAMETEXT_LEFT),
        EndContainer(),
        NWidget(NWID_HORIZONTAL),
                NWidget(WWT_PUSHTXTBTN, COLOUR_MAUVE, WID_GS_EXPAND_ALL), SetDataTip(STR_CONFIG_SETTING_EXPAND_ALL, STR_NULL),
                NWidget(WWT_PUSHTXTBTN, COLOUR_MAUVE, WID_GS_COLLAPSE_ALL), SetDataTip(STR_CONFIG_SETTING_COLLAPSE_ALL, STR_NULL),
                NWidget(WWT_PUSHTXTBTN, COLOUR_MAUVE, WID_GS_RESET_ALL), SetDataTip(STR_CONFIG_SETTING_RESET_ALL, STR_NULL),
                NWidget(WWT_PANEL, COLOUR_MAUVE), SetFill(1, 0), SetResize(1, 0),
                EndContainer(),
                NWidget(WWT_RESIZEBOX, COLOUR_MAUVE),
        EndContainer(),
};

static WindowDesc _settings_selection_desc(
        WDP_CENTER, "settings", 510, 450,
        WC_GAME_OPTIONS, WC_NONE,
        0,
        _nested_settings_selection_widgets, lengthof(_nested_settings_selection_widgets)
);

/** Open advanced settings window. */
void ShowGameSettings()
{
        CloseWindowByClass(WC_GAME_OPTIONS);
        new GameSettingsWindow(&_settings_selection_desc);
}


/**
 * Draw [<][>] boxes.
 * @param x the x position to draw
 * @param y the y position to draw
 * @param button_colour the colour of the button
 * @param state 0 = none clicked, 1 = first clicked, 2 = second clicked
 * @param clickable_left is the left button clickable?
 * @param clickable_right is the right button clickable?
 */
void DrawArrowButtons(int x, int y, Colours button_colour, byte state, bool clickable_left, bool clickable_right)
{
        int colour = _colour_gradient[button_colour][2];
        Dimension dim = NWidgetScrollbar::GetHorizontalDimension();

        DrawFrameRect(x,             y, x + dim.width - 1,             y + dim.height - 1, button_colour, (state == 1) ? FR_LOWERED : FR_NONE);
        DrawFrameRect(x + dim.width, y, x + dim.width + dim.width - 1, y + dim.height - 1, button_colour, (state == 2) ? FR_LOWERED : FR_NONE);
        DrawSprite(SPR_ARROW_LEFT, PAL_NONE, x + WD_IMGBTN_LEFT, y + WD_IMGBTN_TOP);
        DrawSprite(SPR_ARROW_RIGHT, PAL_NONE, x + WD_IMGBTN_LEFT + dim.width, y + WD_IMGBTN_TOP);

        /* Grey out the buttons that aren't clickable */
        bool rtl = _current_text_dir == TD_RTL;
        if (rtl ? !clickable_right : !clickable_left) {
                GfxFillRect(x + 1, y, x + dim.width - 1, y + dim.height - 2, colour, FILLRECT_CHECKER);
        }
        if (rtl ? !clickable_left : !clickable_right) {
                GfxFillRect(x + dim.width + 1, y, x + dim.width + dim.width - 1, y + dim.height - 2, colour, FILLRECT_CHECKER);
        }
}

/**
 * Draw a dropdown button.
 * @param x the x position to draw
 * @param y the y position to draw
 * @param button_colour the colour of the button
 * @param state true = lowered
 * @param clickable is the button clickable?
 */
void DrawDropDownButton(int x, int y, Colours button_colour, bool state, bool clickable)
{
        int colour = _colour_gradient[button_colour][2];

        DrawFrameRect(x, y, x + SETTING_BUTTON_WIDTH - 1, y + SETTING_BUTTON_HEIGHT - 1, button_colour, state ? FR_LOWERED : FR_NONE);
        DrawSprite(SPR_ARROW_DOWN, PAL_NONE, x + (SETTING_BUTTON_WIDTH - NWidgetScrollbar::GetVerticalDimension().width) / 2 + state, y + 2 + state);

        if (!clickable) {
                GfxFillRect(x +  1, y, x + SETTING_BUTTON_WIDTH - 1, y + SETTING_BUTTON_HEIGHT - 2, colour, FILLRECT_CHECKER);
        }
}

/**
 * Draw a toggle button.
 * @param x the x position to draw
 * @param y the y position to draw
 * @param state true = lowered
 * @param clickable is the button clickable?
 */
void DrawBoolButton(int x, int y, bool state, bool clickable)
{
        static const Colours _bool_ctabs[2][2] = {{COLOUR_CREAM, COLOUR_RED}, {COLOUR_DARK_GREEN, COLOUR_GREEN}};
        DrawFrameRect(x, y, x + SETTING_BUTTON_WIDTH - 1, y + SETTING_BUTTON_HEIGHT - 1, _bool_ctabs[state][clickable], state ? FR_LOWERED : FR_NONE);
}

struct CustomCurrencyWindow : Window {
        int query_widget;

        CustomCurrencyWindow(WindowDesc *desc) : Window(desc)
        {
                this->InitNested();

                SetButtonState();
        }

        void SetButtonState()
        {
                this->SetWidgetDisabledState(WID_CC_RATE_DOWN, _custom_currency.rate == 1);
                this->SetWidgetDisabledState(WID_CC_RATE_UP, _custom_currency.rate == UINT16_MAX);
                this->SetWidgetDisabledState(WID_CC_YEAR_DOWN, _custom_currency.to_euro == CF_NOEURO);
                this->SetWidgetDisabledState(WID_CC_YEAR_UP, _custom_currency.to_euro == MAX_YEAR);
        }

        void SetStringParameters(int widget) const override
        {
                switch (widget) {
                        case WID_CC_RATE:      SetDParam(0, 1); SetDParam(1, 1);            break;
                        case WID_CC_SEPARATOR: SetDParamStr(0, _custom_currency.separator); break;
                        case WID_CC_PREFIX:    SetDParamStr(0, _custom_currency.prefix);    break;
                        case WID_CC_SUFFIX:    SetDParamStr(0, _custom_currency.suffix);    break;
                        case WID_CC_YEAR:
                                SetDParam(0, (_custom_currency.to_euro != CF_NOEURO) ? STR_CURRENCY_SWITCH_TO_EURO : STR_CURRENCY_SWITCH_TO_EURO_NEVER);
                                SetDParam(1, _custom_currency.to_euro);
                                break;

                        case WID_CC_PREVIEW:
                                SetDParam(0, 10000);
                                break;
                }
        }

        void UpdateWidgetSize(int widget, Dimension *size, const Dimension &padding, Dimension *fill, Dimension *resize) override
        {
                switch (widget) {
                        /* Set the appropriate width for the edit 'buttons' */
                        case WID_CC_SEPARATOR_EDIT:
                        case WID_CC_PREFIX_EDIT:
                        case WID_CC_SUFFIX_EDIT:
                                size->width  = this->GetWidget<NWidgetBase>(WID_CC_RATE_DOWN)->smallest_x + this->GetWidget<NWidgetBase>(WID_CC_RATE_UP)->smallest_x;
                                break;

                        /* Make sure the window is wide enough for the widest exchange rate */
                        case WID_CC_RATE:
                                SetDParam(0, 1);
                                SetDParam(1, INT32_MAX);
                                *size = GetStringBoundingBox(STR_CURRENCY_EXCHANGE_RATE);
                                break;
                }
        }

        void OnClick(Point pt, int widget, int click_count) override
        {
                int line = 0;
                int len = 0;
                StringID str = 0;
                CharSetFilter afilter = CS_ALPHANUMERAL;

                switch (widget) {
                        case WID_CC_RATE_DOWN:
                                if (_custom_currency.rate > 1) _custom_currency.rate--;
                                if (_custom_currency.rate == 1) this->DisableWidget(WID_CC_RATE_DOWN);
                                this->EnableWidget(WID_CC_RATE_UP);
                                break;

                        case WID_CC_RATE_UP:
                                if (_custom_currency.rate < UINT16_MAX) _custom_currency.rate++;
                                if (_custom_currency.rate == UINT16_MAX) this->DisableWidget(WID_CC_RATE_UP);
                                this->EnableWidget(WID_CC_RATE_DOWN);
                                break;

                        case WID_CC_RATE:
                                SetDParam(0, _custom_currency.rate);
                                str = STR_JUST_INT;
                                len = 5;
                                line = WID_CC_RATE;
                                afilter = CS_NUMERAL;
                                break;

                        case WID_CC_SEPARATOR_EDIT:
                        case WID_CC_SEPARATOR:
                                SetDParamStr(0, _custom_currency.separator);
                                str = STR_JUST_RAW_STRING;
                                len = 7;
                                line = WID_CC_SEPARATOR;
                                break;

                        case WID_CC_PREFIX_EDIT:
                        case WID_CC_PREFIX:
                                SetDParamStr(0, _custom_currency.prefix);
                                str = STR_JUST_RAW_STRING;
                                len = 15;
                                line = WID_CC_PREFIX;
                                break;

                        case WID_CC_SUFFIX_EDIT:
                        case WID_CC_SUFFIX:
                                SetDParamStr(0, _custom_currency.suffix);
                                str = STR_JUST_RAW_STRING;
                                len = 15;
                                line = WID_CC_SUFFIX;
                                break;

                        case WID_CC_YEAR_DOWN:
                                _custom_currency.to_euro = (_custom_currency.to_euro <= 2000) ? CF_NOEURO : _custom_currency.to_euro - 1;
                                if (_custom_currency.to_euro == CF_NOEURO) this->DisableWidget(WID_CC_YEAR_DOWN);
                                this->EnableWidget(WID_CC_YEAR_UP);
                                break;

                        case WID_CC_YEAR_UP:
                                _custom_currency.to_euro = Clamp(_custom_currency.to_euro + 1, 2000, MAX_YEAR);
                                if (_custom_currency.to_euro == MAX_YEAR) this->DisableWidget(WID_CC_YEAR_UP);
                                this->EnableWidget(WID_CC_YEAR_DOWN);
                                break;

                        case WID_CC_YEAR:
                                SetDParam(0, _custom_currency.to_euro);
                                str = STR_JUST_INT;
                                len = 7;
                                line = WID_CC_YEAR;
                                afilter = CS_NUMERAL;
                                break;
                }

                if (len != 0) {
                        this->query_widget = line;
                        ShowQueryString(str, STR_CURRENCY_CHANGE_PARAMETER, len + 1, this, afilter, QSF_NONE);
                }

                this->SetTimeout();
                this->SetDirty();
        }

        void OnQueryTextFinished(char *str) override
        {
                if (str == nullptr) return;

                switch (this->query_widget) {
                        case WID_CC_RATE:
                                _custom_currency.rate = Clamp(atoi(str), 1, UINT16_MAX);
                                break;

                        case WID_CC_SEPARATOR: // Thousands separator
                                _custom_currency.separator = str;
                                break;

                        case WID_CC_PREFIX:
                                _custom_currency.prefix = str;
                                break;

                        case WID_CC_SUFFIX:
                                _custom_currency.suffix = str;
                                break;

                        case WID_CC_YEAR: { // Year to switch to euro
                                int val = atoi(str);

                                _custom_currency.to_euro = (val < 2000 ? CF_NOEURO : std::min(val, MAX_YEAR));
                                break;
                        }
                }
                MarkWholeScreenDirty();
                SetButtonState();
        }

        void OnTimeout() override
        {
                this->SetDirty();
        }
};

static const NWidgetPart _nested_cust_currency_widgets[] = {
        NWidget(NWID_HORIZONTAL),
                NWidget(WWT_CLOSEBOX, COLOUR_GREY),
                NWidget(WWT_CAPTION, COLOUR_GREY), SetDataTip(STR_CURRENCY_WINDOW, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS),
        EndContainer(),
        NWidget(WWT_PANEL, COLOUR_GREY),
                NWidget(NWID_VERTICAL, NC_EQUALSIZE), SetPIP(7, 3, 0),
                        NWidget(NWID_HORIZONTAL), SetPIP(10, 0, 5),
                                NWidget(WWT_PUSHARROWBTN, COLOUR_YELLOW, WID_CC_RATE_DOWN), SetDataTip(AWV_DECREASE, STR_CURRENCY_DECREASE_EXCHANGE_RATE_TOOLTIP),
                                NWidget(WWT_PUSHARROWBTN, COLOUR_YELLOW, WID_CC_RATE_UP), SetDataTip(AWV_INCREASE, STR_CURRENCY_INCREASE_EXCHANGE_RATE_TOOLTIP),
                                NWidget(NWID_SPACER), SetMinimalSize(5, 0),
                                NWidget(WWT_TEXT, COLOUR_BLUE, WID_CC_RATE), SetDataTip(STR_CURRENCY_EXCHANGE_RATE, STR_CURRENCY_SET_EXCHANGE_RATE_TOOLTIP), SetFill(1, 0),
                        EndContainer(),
                        NWidget(NWID_HORIZONTAL), SetPIP(10, 0, 5),
                                NWidget(WWT_PUSHBTN, COLOUR_DARK_BLUE, WID_CC_SEPARATOR_EDIT), SetDataTip(0x0, STR_CURRENCY_SET_CUSTOM_CURRENCY_SEPARATOR_TOOLTIP), SetFill(0, 1),
                                NWidget(NWID_SPACER), SetMinimalSize(5, 0),
                                NWidget(WWT_TEXT, COLOUR_BLUE, WID_CC_SEPARATOR), SetDataTip(STR_CURRENCY_SEPARATOR, STR_CURRENCY_SET_CUSTOM_CURRENCY_SEPARATOR_TOOLTIP), SetFill(1, 0),
                        EndContainer(),
                        NWidget(NWID_HORIZONTAL), SetPIP(10, 0, 5),
                                NWidget(WWT_PUSHBTN, COLOUR_DARK_BLUE, WID_CC_PREFIX_EDIT), SetDataTip(0x0, STR_CURRENCY_SET_CUSTOM_CURRENCY_PREFIX_TOOLTIP), SetFill(0, 1),
                                NWidget(NWID_SPACER), SetMinimalSize(5, 0),
                                NWidget(WWT_TEXT, COLOUR_BLUE, WID_CC_PREFIX), SetDataTip(STR_CURRENCY_PREFIX, STR_CURRENCY_SET_CUSTOM_CURRENCY_PREFIX_TOOLTIP), SetFill(1, 0),
                        EndContainer(),
                        NWidget(NWID_HORIZONTAL), SetPIP(10, 0, 5),
                                NWidget(WWT_PUSHBTN, COLOUR_DARK_BLUE, WID_CC_SUFFIX_EDIT), SetDataTip(0x0, STR_CURRENCY_SET_CUSTOM_CURRENCY_SUFFIX_TOOLTIP), SetFill(0, 1),
                                NWidget(NWID_SPACER), SetMinimalSize(5, 0),
                                NWidget(WWT_TEXT, COLOUR_BLUE, WID_CC_SUFFIX), SetDataTip(STR_CURRENCY_SUFFIX, STR_CURRENCY_SET_CUSTOM_CURRENCY_SUFFIX_TOOLTIP), SetFill(1, 0),
                        EndContainer(),
                        NWidget(NWID_HORIZONTAL), SetPIP(10, 0, 5),
                                NWidget(WWT_PUSHARROWBTN, COLOUR_YELLOW, WID_CC_YEAR_DOWN), SetDataTip(AWV_DECREASE, STR_CURRENCY_DECREASE_CUSTOM_CURRENCY_TO_EURO_TOOLTIP),
                                NWidget(WWT_PUSHARROWBTN, COLOUR_YELLOW, WID_CC_YEAR_UP), SetDataTip(AWV_INCREASE, STR_CURRENCY_INCREASE_CUSTOM_CURRENCY_TO_EURO_TOOLTIP),
                                NWidget(NWID_SPACER), SetMinimalSize(5, 0),
                                NWidget(WWT_TEXT, COLOUR_BLUE, WID_CC_YEAR), SetDataTip(STR_JUST_STRING, STR_CURRENCY_SET_CUSTOM_CURRENCY_TO_EURO_TOOLTIP), SetFill(1, 0),
                        EndContainer(),
                EndContainer(),
                NWidget(WWT_LABEL, COLOUR_BLUE, WID_CC_PREVIEW),
                                                                SetDataTip(STR_CURRENCY_PREVIEW, STR_CURRENCY_CUSTOM_CURRENCY_PREVIEW_TOOLTIP), SetPadding(15, 1, 18, 2),
        EndContainer(),
};

static WindowDesc _cust_currency_desc(
        WDP_CENTER, nullptr, 0, 0,
        WC_CUSTOM_CURRENCY, WC_NONE,
        0,
        _nested_cust_currency_widgets, lengthof(_nested_cust_currency_widgets)
);

/** Open custom currency window. */
static void ShowCustCurrency()
{
        CloseWindowById(WC_CUSTOM_CURRENCY, 0);
        new CustomCurrencyWindow(&_cust_currency_desc);
}