handler.cpp

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/*
    Copyright (C) 2009 - 2021
    by Mark de Wever <koraq@xs4all.nl>
    Part of the Battle for Wesnoth Project https://www.wesnoth.org/

    This program 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; either version 2 of the License, or
    (at your option) any later version.
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY.

    See the COPYING file for more details.
*/

#define GETTEXT_DOMAIN "wesnoth-lib"

#include "gui/core/event/handler.hpp"

#include "gui/core/event/dispatcher.hpp"
#include "gui/core/timer.hpp"
#include "gui/core/log.hpp"
#include "gui/widgets/helper.hpp"
#include "gui/widgets/widget.hpp"
#include "gui/widgets/window.hpp"
#include "hotkey/hotkey_item.hpp"
#include "video.hpp"
#include "serialization/unicode_cast.hpp"
#include "sdl/userevent.hpp"
#include "utils/ranges.hpp"

#include <cassert>

/**
 * @todo The items below are not implemented yet.
 *
 * - Tooltips have a fixed short time until showing up.
 * - Tooltips are shown until the widget is exited.
 * - Help messages aren't shown yet.
 *
 * @note it might be that tooltips will be shown independent of a window and in
 * their own window, therefore the code will be cleaned up after that has been
 * determined.
 */

/*
 * At some point in the future this event handler should become the main event
 * handler. This switch controls the experimental switch for that change.
 */
//#define MAIN_EVENT_HANDLER

/* Since this code is still very experimental it's not enabled yet. */
//#define ENABLE

namespace gui2
{

namespace event
{

/***** Static data. *****/
static std::unique_ptr<class sdl_event_handler> handler_ = nullptr;
static events::event_context* event_context = nullptr;

#ifdef MAIN_EVENT_HANDLER
static unsigned draw_interval = 0;
static unsigned event_poll_interval = 0;

/***** Static functions. *****/

/**
 * SDL_AddTimer() callback for the draw event.
 *
 * When this callback is called it pushes a new draw event in the event queue.
 *
 * @returns                       The new timer interval, 0 to stop.
 */
static uint32_t timer_sdl_draw_event(uint32_t, void*)
{
    // DBG_GUI_E << "Pushing draw event in queue.\n";

    SDL_Event event;
    sdl::UserEvent data(DRAW_EVENT);

    event.type = DRAW_EVENT;
    event.user = data;

    SDL_PushEvent(&event);
    return draw_interval;
}

/**
 * SDL_AddTimer() callback for the poll event.
 *
 * When this callback is called it will run the events in the SDL event queue.
 *
 * @returns                       The new timer interval, 0 to stop.
 */
static uint32_t timer_sdl_poll_events(uint32_t, void*)
{
    try
    {
        events::pump();
    }
    catch(CVideo::quit&)
    {
        return 0;
    }
    return event_poll_interval;
}
#endif

/***** handler class. *****/

/**
 * This singleton class handles all events.
 *
 * It's a new experimental class.
 */
class sdl_event_handler : public events::sdl_handler
{
    friend bool gui2::is_in_dialog();

public:
    sdl_event_handler();

    ~sdl_event_handler();

    /** Inherited from events::sdl_handler. */
    void handle_event(const SDL_Event& event) override;

    /** Inherited from events::sdl_handler. */
    void handle_window_event(const SDL_Event& event) override;

    /**
     * Connects a dispatcher.
     *
     * @param dispatcher              The dispatcher to connect.
     */
    void connect(dispatcher* dispatcher);

    /**
     * Disconnects a dispatcher.
     *
     * @param dispatcher              The dispatcher to disconnect.
     */
    void disconnect(dispatcher* dispatcher);

    /**
     * Returns all dispatchers in the Z order.
     */
    std::vector<dispatcher*>& get_dispatchers() { return dispatchers_; }

    /** The dispatcher that captured the mouse focus. */
    dispatcher* mouse_focus;

private:
    /**
     * Reinitializes the state of all dispatchers.
     *
     * This is needed when the application gets activated, to make sure the
     * state of mainly the mouse is set properly.
     */
    void activate();

    /***** Handlers *****/

    /** Fires a raw SDL event. */
    void raw_event(const SDL_Event &event);

    /** Fires a draw event. */
    using events::sdl_handler::draw;
    void draw() override;
    void draw_everything();

    /**
     * Fires a video resize event.
     *
     * @param new_size               The new size of the window.
     */
    void video_resize(const point& new_size);

    /**
     * Fires a generic mouse event.
     *
     * @param event                  The event to fire.
     * @param position               The position of the mouse.
     */
    void mouse(const ui_event event, const point& position);

    /**
     * Fires a mouse button up event.
     *
     * @param position               The position of the mouse.
     * @param button                 The SDL id of the button that caused the
     *                               event.
     */
    void mouse_button_up(const point& position, const uint8_t button);

    /**
     * Fires a mouse button down event.
     *
     * @param position               The position of the mouse.
     * @param button                 The SDL id of the button that caused the
     *                               event.
     */
    void mouse_button_down(const point& position, const uint8_t button);

    /**
     * Fires a mouse wheel event.
     *
     * @param position               The position of the mouse.
     * @param scrollx                The amount of horizontal scrolling.
     * @param scrolly                The amount of vertical scrolling.
     */
    void mouse_wheel(const point& position, int scrollx, int scrolly);

    /**
     * Gets the dispatcher that wants to receive the keyboard input.
     *
     * @returns                   The dispatcher.
     * @retval nullptr               No dispatcher found.
     */
    dispatcher* keyboard_dispatcher();

    /**
     * Fires a touch-moved event.
     *
     * @param position               The position touched.
     * @param distance               The distance moved.
     */
    void touch_motion(const point& position, const point& distance);

    /**
     * Fires a touch "finger down" event.
     *
     * @param position               The position touched.
     */
    void touch_down(const point& position);

    /**
     * Fires a touch "finger up" event.
     *
     * @param position               The position touched.
     */
    void touch_up(const point& position);

    /**
     * Fires a touch gesture event.
     * @param center                the center of gesture
     * @param dTheta                the amount that the fingers rotated during this motion
     * @param dDist                 the amount that the fingers pinched during this motion
     * @param numFingers            the number of fingers used in the gesture
     */
    void touch_multi_gesture(const point& center, float dTheta, float dDist, uint8_t numFingers);

    /**
     * Handles a hat motion event.
     *
     * @param event                  The SDL joystick hat event triggered.
     */
    void hat_motion(const SDL_Event& event);

    /**
     * Handles a joystick button down event.
     *
     * @param event                  The SDL joystick button event triggered.
     */
    void button_down(const SDL_Event& event);

    /**
     * Fires a key down event.
     *
     * @param event                  The SDL keyboard event triggered.
     */
    void key_down(const SDL_Event& event);

    /**
     * Handles the pressing of a hotkey.
     *
     * @param key                 The hotkey item pressed.
     *
     * @returns                   True if there was a valid dispatcher with
     *                            which to execute the hotkey callback, false
     *                            otherwise.
     */
    bool hotkey_pressed(const hotkey::hotkey_ptr key);

    /**
     * Fires a key down event.
     *
     * @param key                    The SDL key code of the key pressed.
     * @param modifier               The SDL key modifiers used.
     * @param unicode                The unicode value for the key pressed.
     */
    void key_down(const SDL_Keycode key,
                  const SDL_Keymod modifier,
                  const std::string& unicode);

    /**
     * Fires a text input event.
     *
     * @param unicode                The unicode value for the text entered.
     */
    void text_input(const std::string& unicode);

    /**
     * Fires a text editing event.
     *
     * @param unicode                The unicode value for the text being edited.
     * @param start                  The start position for the text being edited.
     * @param len                    The selection length for the text being edited.
     */
    void text_editing(const std::string& unicode, int32_t start, int32_t len);

    /**
     * Fires a keyboard event which has no parameters.
     *
     * This can happen for example when the mouse wheel is used.
     *
     * @param event                  The event to fire.
     */
    void keyboard(const ui_event event);

    /**
     * Fires a CLOSE_WINDOW event for the window with the given ID.
     *
     * @param window_id              The ID of the window to close.
     */
    void close_window(const unsigned window_id);

    /**
     * The dispatchers.
     *
     * The order of the items in the list is also the z-order the front item
     * being the one completely in the background and the back item the one
     * completely in the foreground.
     */
    std::vector<dispatcher*> dispatchers_;

    /**
     * Needed to determine which dispatcher gets the keyboard events.
     *
     * NOTE the keyboard events aren't really wired in yet so doesn't do much.
     */
    dispatcher* keyboard_focus_;
    friend void capture_keyboard(dispatcher* dispatcher);
};

sdl_event_handler::sdl_event_handler()
    : events::sdl_handler(false)
    , mouse_focus(nullptr)
    , dispatchers_()
    , keyboard_focus_(nullptr)
{
    if(SDL_WasInit(SDL_INIT_TIMER) == 0) {
        if(SDL_InitSubSystem(SDL_INIT_TIMER) == -1) {
            assert(false);
        }
    }

// The event context is created now we join it.
#ifdef ENABLE
    join();
#endif
}

sdl_event_handler::~sdl_event_handler()
{
#ifdef ENABLE
    leave();
#endif
}

void sdl_event_handler::handle_event(const SDL_Event& event)
{
    /** No dispatchers drop the event. */
    if(dispatchers_.empty()) {
        return;
    }

    uint8_t button = event.button.button;
    CVideo& video = CVideo::get_singleton();

    switch(event.type) {
        case SDL_MOUSEMOTION:
#ifdef MOUSE_TOUCH_EMULATION
            // There's no finger motion when it's not down.
            if (event.motion.state != 0)
#endif
            {
                mouse(SDL_MOUSE_MOTION, {event.motion.x, event.motion.y});
            }
            break;

        case SDL_MOUSEBUTTONDOWN:
            {
                mouse_button_down({event.button.x, event.button.y}, button);
            }
            break;

        case SDL_MOUSEBUTTONUP:
            {
                mouse_button_up({event.button.x, event.button.y}, button);
            }
            break;

        case SDL_MOUSEWHEEL:
            mouse_wheel(get_mouse_position(), event.wheel.x, event.wheel.y);
            break;

        case SHOW_HELPTIP_EVENT:
            mouse(SHOW_HELPTIP, get_mouse_position());
            break;

        case HOVER_REMOVE_POPUP_EVENT:
            // remove_popup();
            break;

        case DRAW_EVENT:
            draw();
            break;

        case DRAW_ALL_EVENT:
            draw_everything();
            break;

        case TIMER_EVENT:
            execute_timer(reinterpret_cast<std::size_t>(event.user.data1));
            break;

        case CLOSE_WINDOW_EVENT:
            close_window(event.user.code);
            break;

        case SDL_JOYBUTTONDOWN:
            button_down(event);
            break;

        case SDL_JOYBUTTONUP:
            break;

        case SDL_JOYAXISMOTION:
            break;

        case SDL_JOYHATMOTION:
            hat_motion(event);
            break;

        case SDL_KEYDOWN:
            key_down(event);
            break;

        case SDL_WINDOWEVENT:
            switch(event.window.event) {
                case SDL_WINDOWEVENT_EXPOSED:
                    draw();
                    break;

                case SDL_WINDOWEVENT_RESIZED:
                    video_resize({event.window.data1, event.window.data2});
                    break;

                case SDL_WINDOWEVENT_ENTER:
                case SDL_WINDOWEVENT_FOCUS_GAINED:
                    activate();
                    break;
            }

            break;

        case SDL_TEXTINPUT:
            key_down(event);
            break;

        case SDL_TEXTEDITING:
            text_editing(event.edit.text, event.edit.start, event.edit.length);
            break;

        case SDL_FINGERMOTION:
            {
                SDL_Rect r = video.screen_area();
                touch_motion(point(event.tfinger.x * r.w, event.tfinger.y * r.h),
                             point(event.tfinger.dx * r.w, event.tfinger.dy * r.h));
            }
            break;

        case SDL_FINGERUP:
            {
                SDL_Rect r = video.screen_area();
                touch_up(point(event.tfinger.x * r.w, event.tfinger.y * r.h));
            }
            break;

        case SDL_FINGERDOWN:
            {
                SDL_Rect r = video.screen_area();
                touch_down(point(event.tfinger.x * r.w, event.tfinger.y * r.h));
            }
            break;

        case SDL_MULTIGESTURE:
            {
                SDL_Rect r = video.screen_area();
                touch_multi_gesture(point(event.mgesture.x * r.w, event.mgesture.y * r.h),
                                    event.mgesture.dTheta, event.mgesture.dDist, event.mgesture.numFingers);
            }
            break;

#if(defined(_X11) && !defined(__APPLE__)) || defined(_WIN32)
        case SDL_SYSWMEVENT:
            /* DO NOTHING */
            break;
#endif

        // Silently ignored events.
        case SDL_KEYUP:
        case DOUBLE_CLICK_EVENT:
            break;

        default:
#ifdef GUI2_SHOW_UNHANDLED_EVENT_WARNINGS
            WRN_GUI_E << "Unhandled event " << static_cast<uint32_t>(event.type)
                      << ".\n";
#endif
            break;
    }

    raw_event(event);
}

void sdl_event_handler::handle_window_event(const SDL_Event& event)
{
    handle_event(event);
}

void sdl_event_handler::connect(dispatcher* dispatcher)
{
    assert(std::find(dispatchers_.begin(), dispatchers_.end(), dispatcher)
           == dispatchers_.end());

    if(dispatchers_.empty()) {
        event_context = new events::event_context();
        join();
    }

    dispatchers_.push_back(dispatcher);
}

void sdl_event_handler::disconnect(dispatcher* disp)
{
    /***** Validate pre conditions. *****/
    auto itor = std::find(dispatchers_.begin(), dispatchers_.end(), disp);
    assert(itor != dispatchers_.end());

    /***** Remove dispatcher. *****/
    dispatchers_.erase(itor);

    if(disp == mouse_focus) {
        mouse_focus = nullptr;
    }
    if(disp == keyboard_focus_) {
        keyboard_focus_ = nullptr;
    }

    /***** Set proper state for the other dispatchers. *****/
    for(auto d : dispatchers_)
    {
        dynamic_cast<widget&>(*d).set_is_dirty(true);
    }

    activate();

    /***** Validate post conditions. *****/
    assert(std::find(dispatchers_.begin(), dispatchers_.end(), disp)
           == dispatchers_.end());

    if(dispatchers_.empty()) {
        leave();
        delete event_context;
        event_context = nullptr;
    }
}

void sdl_event_handler::activate()
{
    for(auto dispatcher : dispatchers_)
    {
        dispatcher->fire(SDL_ACTIVATE, dynamic_cast<widget&>(*dispatcher), nullptr);
    }
}

void sdl_event_handler::draw()
{
    for(auto dispatcher : dispatchers_)
    {
        dispatcher->fire(DRAW, dynamic_cast<widget&>(*dispatcher));
    }

    if(!dispatchers_.empty()) {
        CVideo::get_singleton().flip();
    }
}

void sdl_event_handler::draw_everything()
{
    for(auto dispatcher : dispatchers_) {
        dynamic_cast<widget&>(*dispatcher).set_is_dirty(true);
    }

    draw();
}

void sdl_event_handler::video_resize(const point& new_size)
{
    DBG_GUI_E << "Firing: " << SDL_VIDEO_RESIZE << ".\n";

    for(auto dispatcher : dispatchers_)
    {
        dispatcher->fire(SDL_VIDEO_RESIZE, dynamic_cast<widget&>(*dispatcher), new_size);
    }
}

void sdl_event_handler::raw_event(const SDL_Event& event) {
    DBG_GUI_E << "Firing raw event\n";

    for(auto dispatcher : dispatchers_)
    {
        dispatcher->fire(SDL_RAW_EVENT, dynamic_cast<widget&>(*dispatcher), event);
    }
}

void sdl_event_handler::mouse(const ui_event event, const point& position)
{
    DBG_GUI_E << "Firing: " << event << ".\n";

    if(mouse_focus) {
        mouse_focus->fire(event, dynamic_cast<widget&>(*mouse_focus), position);
        return;
    }

    for(auto& dispatcher : utils::reversed_view(dispatchers_)) {
        if(dispatcher->get_mouse_behavior() == dispatcher::all) {
            dispatcher->fire(event, dynamic_cast<widget&>(*dispatcher), position);
            break;
        }

        if(dispatcher->get_mouse_behavior() == dispatcher::none) {
            continue;
        }

        if(dispatcher->is_at(position)) {
            dispatcher->fire(event, dynamic_cast<widget&>(*dispatcher), position);
            break;
        }
    }
}

void sdl_event_handler::mouse_button_up(const point& position, const uint8_t button)
{
    switch(button) {
        case SDL_BUTTON_LEFT:
            mouse(SDL_LEFT_BUTTON_UP, position);
            break;
        case SDL_BUTTON_MIDDLE:
            mouse(SDL_MIDDLE_BUTTON_UP, position);
            break;
        case SDL_BUTTON_RIGHT:
            mouse(SDL_RIGHT_BUTTON_UP, position);
            break;
        default:
#ifdef GUI2_SHOW_UNHANDLED_EVENT_WARNINGS
            WRN_GUI_E << "Unhandled 'mouse button up' event for button "
                      << static_cast<uint32_t>(button) << ".\n";
#endif
            break;
    }
}

void sdl_event_handler::mouse_button_down(const point& position, const uint8_t button)
{
    switch(button) {
        case SDL_BUTTON_LEFT:
            mouse(SDL_LEFT_BUTTON_DOWN, position);
            break;
        case SDL_BUTTON_MIDDLE:
            mouse(SDL_MIDDLE_BUTTON_DOWN, position);
            break;
        case SDL_BUTTON_RIGHT:
            mouse(SDL_RIGHT_BUTTON_DOWN, position);
            break;
        default:
#ifdef GUI2_SHOW_UNHANDLED_EVENT_WARNINGS
            WRN_GUI_E << "Unhandled 'mouse button down' event for button "
                      << static_cast<uint32_t>(button) << ".\n";
#endif
            break;
    }
}

void sdl_event_handler::mouse_wheel(const point& position, int x, int y)
{
    if(x > 0) {
        mouse(SDL_WHEEL_RIGHT, position);
    } else if(x < 0) {
        mouse(SDL_WHEEL_LEFT, position);
    }

    if(y < 0) {
        mouse(SDL_WHEEL_DOWN, position);
    } else if(y > 0) {
        mouse(SDL_WHEEL_UP, position);
    }
}

dispatcher* sdl_event_handler::keyboard_dispatcher()
{
    if(keyboard_focus_) {
        return keyboard_focus_;
    }

    for(auto& dispatcher : utils::reversed_view(dispatchers_)) {
        if(dispatcher->get_want_keyboard_input()) {
            return dispatcher;
        }
    }

    return nullptr;
}

void sdl_event_handler::touch_motion(const point& position, const point& distance)
{
    for(auto& dispatcher : utils::reversed_view(dispatchers_)) {
        dispatcher->fire(SDL_TOUCH_MOTION , dynamic_cast<widget&>(*dispatcher), position, distance);
    }
}

void sdl_event_handler::touch_up(const point& position)
{
    for(auto& dispatcher : utils::reversed_view(dispatchers_)) {
        dispatcher->fire(SDL_TOUCH_UP, dynamic_cast<widget&>(*dispatcher), position);
    }
}

void sdl_event_handler::touch_down(const point& position)
{
    for(auto& dispatcher : utils::reversed_view(dispatchers_)) {
        dispatcher->fire(SDL_TOUCH_DOWN, dynamic_cast<widget&>(*dispatcher), position);
    }
}

void sdl_event_handler::touch_multi_gesture(const point& center, float dTheta, float dDist, uint8_t numFingers)
{
    for(auto& dispatcher : utils::reversed_view(dispatchers_)) {
        dispatcher->fire(SDL_TOUCH_MULTI_GESTURE, dynamic_cast<widget&>(*dispatcher), center, dTheta, dDist, numFingers);
    }
}

void sdl_event_handler::hat_motion(const SDL_Event& event)
{
    const hotkey::hotkey_ptr& hk = hotkey::get_hotkey(event);
    bool done = false;
    if(!hk->null()) {
        done = hotkey_pressed(hk);
    }
    if(!done) {
        // TODO fendrin think about handling hat motions that are not bound to a
        // hotkey.
    }
}

void sdl_event_handler::button_down(const SDL_Event& event)
{
    const hotkey::hotkey_ptr hk = hotkey::get_hotkey(event);
    bool done = false;
    if(!hk->null()) {
        done = hotkey_pressed(hk);
    }
    if(!done) {
        // TODO fendrin think about handling button down events that are not
        // bound to a hotkey.
    }
}

void sdl_event_handler::key_down(const SDL_Event& event)
{
    const hotkey::hotkey_ptr hk = hotkey::get_hotkey(event);
    bool done = false;
    if(!hk->null()) {
        done = hotkey_pressed(hk);
    }
    if(!done) {
        if(event.type == SDL_TEXTINPUT) {
            text_input(event.text.text);
        } else {
            key_down(event.key.keysym.sym, static_cast<SDL_Keymod>(event.key.keysym.mod), "");
        }
    }
}

void sdl_event_handler::text_input(const std::string& unicode)
{
    key_down(SDLK_UNKNOWN, static_cast<SDL_Keymod>(0), unicode);

    if(dispatcher* dispatcher = keyboard_dispatcher()) {
        dispatcher->fire(SDL_TEXT_INPUT,
            dynamic_cast<widget&>(*dispatcher),
            unicode, -1, -1);
    }
}

void sdl_event_handler::text_editing(const std::string& unicode, int32_t start, int32_t len)
{
    if(dispatcher* dispatcher = keyboard_dispatcher()) {
        dispatcher->fire(SDL_TEXT_EDITING,
            dynamic_cast<widget&>(*dispatcher),
            unicode, start, len);
    }
}

bool sdl_event_handler::hotkey_pressed(const hotkey::hotkey_ptr key)
{
    if(dispatcher* dispatcher = keyboard_dispatcher()) {
        return dispatcher->execute_hotkey(hotkey::get_id(key->get_command()));
    }

    return false;
}

void sdl_event_handler::key_down(const SDL_Keycode key,
                        const SDL_Keymod modifier,
                        const std::string& unicode)
{
    DBG_GUI_E << "Firing: " << SDL_KEY_DOWN << ".\n";

    if(dispatcher* dispatcher = keyboard_dispatcher()) {
        dispatcher->fire(SDL_KEY_DOWN,
                         dynamic_cast<widget&>(*dispatcher),
                         key,
                         modifier,
                         unicode);
    }
}

void sdl_event_handler::keyboard(const ui_event event)
{
    DBG_GUI_E << "Firing: " << event << ".\n";

    if(dispatcher* dispatcher = keyboard_dispatcher()) {
        dispatcher->fire(event, dynamic_cast<widget&>(*dispatcher));
    }
}

void sdl_event_handler::close_window(const unsigned window_id)
{
    DBG_GUI_E << "Firing " << CLOSE_WINDOW << ".\n";

    window* window = window::window_instance(window_id);
    if(window) {
        window->fire(CLOSE_WINDOW, *window);
    }
}

/***** manager class. *****/

manager::manager()
{
    handler_.reset(new sdl_event_handler());

#ifdef MAIN_EVENT_HANDLER
    draw_interval = 30;
    SDL_AddTimer(draw_interval, timer_sdl_draw_event, nullptr);

    event_poll_interval = 10;
    SDL_AddTimer(event_poll_interval, timer_sdl_poll_events, nullptr);
#endif
}

manager::~manager()
{
    handler_.reset(nullptr);

#ifdef MAIN_EVENT_HANDLER
    draw_interval = 0;
    event_poll_interval = 0;
#endif
}

/***** free functions class. *****/

void connect_dispatcher(dispatcher* dispatcher)
{
    assert(handler_);
    assert(dispatcher);
    handler_->connect(dispatcher);
}

void disconnect_dispatcher(dispatcher* dispatcher)
{
    assert(handler_);
    assert(dispatcher);
    handler_->disconnect(dispatcher);
}

std::vector<dispatcher*>& get_all_dispatchers()
{
    assert(handler_);
    return handler_->get_dispatchers();
}

void init_mouse_location()
{
    point mouse = get_mouse_position();

    SDL_Event event{};
    event.type = SDL_MOUSEMOTION;
    event.motion.type = SDL_MOUSEMOTION;
    event.motion.x = mouse.x;
    event.motion.y = mouse.y;

    SDL_PushEvent(&event);
}

void capture_mouse(dispatcher* dispatcher)
{
    assert(handler_);
    assert(dispatcher);
    handler_->mouse_focus = dispatcher;
}

void release_mouse(dispatcher* dispatcher)
{
    assert(handler_);
    assert(dispatcher);
    if(handler_->mouse_focus == dispatcher) {
        handler_->mouse_focus = nullptr;
    }
}

void capture_keyboard(dispatcher* dispatcher)
{
    assert(handler_);
    assert(dispatcher);
    assert(dispatcher->get_want_keyboard_input());

    handler_->keyboard_focus_ = dispatcher;
}

std::ostream& operator<<(std::ostream& stream, const ui_event event)
{
    switch(event) {
        case DRAW:
            stream << "draw";
            break;
        case CLOSE_WINDOW:
            stream << "close window";
            break;
        case SDL_VIDEO_RESIZE:
            stream << "SDL video resize";
            break;
        case SDL_MOUSE_MOTION:
            stream << "SDL mouse motion";
            break;
        case MOUSE_ENTER:
            stream << "mouse enter";
            break;
        case MOUSE_LEAVE:
            stream << "mouse leave";
            break;
        case MOUSE_MOTION:
            stream << "mouse motion";
            break;
        case SDL_LEFT_BUTTON_DOWN:
            stream << "SDL left button down";
            break;
        case SDL_LEFT_BUTTON_UP:
            stream << "SDL left button up";
            break;
        case LEFT_BUTTON_DOWN:
            stream << "left button down";
            break;
        case LEFT_BUTTON_UP:
            stream << "left button up";
            break;
        case LEFT_BUTTON_CLICK:
            stream << "left button click";
            break;
        case LEFT_BUTTON_DOUBLE_CLICK:
            stream << "left button double click";
            break;
        case SDL_MIDDLE_BUTTON_DOWN:
            stream << "SDL middle button down";
            break;
        case SDL_MIDDLE_BUTTON_UP:
            stream << "SDL middle button up";
            break;
        case MIDDLE_BUTTON_DOWN:
            stream << "middle button down";
            break;
        case MIDDLE_BUTTON_UP:
            stream << "middle button up";
            break;
        case MIDDLE_BUTTON_CLICK:
            stream << "middle button click";
            break;
        case MIDDLE_BUTTON_DOUBLE_CLICK:
            stream << "middle button double click";
            break;
        case SDL_RIGHT_BUTTON_DOWN:
            stream << "SDL right button down";
            break;
        case SDL_RIGHT_BUTTON_UP:
            stream << "SDL right button up";
            break;
        case RIGHT_BUTTON_DOWN:
            stream << "right button down";
            break;
        case RIGHT_BUTTON_UP:
            stream << "right button up";
            break;
        case RIGHT_BUTTON_CLICK:
            stream << "right button click";
            break;
        case RIGHT_BUTTON_DOUBLE_CLICK:
            stream << "right button double click";
            break;
        case SDL_WHEEL_LEFT:
            stream << "SDL wheel left";
            break;
        case SDL_WHEEL_RIGHT:
            stream << "SDL wheel right";
            break;
        case SDL_WHEEL_UP:
            stream << "SDL wheel up";
            break;
        case SDL_WHEEL_DOWN:
            stream << "SDL wheel down";
            break;
        case SDL_KEY_DOWN:
            stream << "SDL key down";
            break;
        case SDL_TEXT_INPUT:
            stream << "SDL text input";
            break;
        case SDL_TEXT_EDITING:
            stream << "SDL text editing";
            break;

        case NOTIFY_REMOVAL:
            stream << "notify removal";
            break;
        case NOTIFY_MODIFIED:
            stream << "notify modified";
            break;
        case RECEIVE_KEYBOARD_FOCUS:
            stream << "receive keyboard focus";
            break;
        case LOSE_KEYBOARD_FOCUS:
            stream << "lose keyboard focus";
            break;
        case SHOW_TOOLTIP:
            stream << "show tooltip";
            break;
        case NOTIFY_REMOVE_TOOLTIP:
            stream << "notify remove tooltip";
            break;
        case SDL_ACTIVATE:
            stream << "SDL activate";
            break;
        case MESSAGE_SHOW_TOOLTIP:
            stream << "message show tooltip";
            break;
        case SHOW_HELPTIP:
            stream << "show helptip";
            break;
        case MESSAGE_SHOW_HELPTIP:
            stream << "message show helptip";
            break;
        case REQUEST_PLACEMENT:
            stream << "request placement";
            break;
        case SDL_TOUCH_MOTION:
            stream << "SDL touch motion";
            break;
        case SDL_TOUCH_UP:
            stream << "SDL touch up";
            break;
        case SDL_TOUCH_DOWN:
            stream << "SDL touch down";
            break;
        case SDL_TOUCH_MULTI_GESTURE:
            stream << "SDL multi-touch gesture";
            break;
        case SDL_RAW_EVENT:
            stream << "SDL raw event";
            break;
    }

    return stream;
}

} // namespace event

std::vector<window*> open_window_stack {};

void remove_from_window_stack(window* window)
{
    for(auto iter = open_window_stack.rbegin(); iter != open_window_stack.rend(); ++iter) {
        if(*iter == window) {
            open_window_stack.erase(std::next(iter).base());
            break;
        }
    }
}

bool is_in_dialog()
{
    return !open_window_stack.empty();
}

} // namespace gui2