struct State
{
    State()
        : counter(0)
    {
    }

    State with_counter(int counter) const
    {
        State copy(*this);
        copy.counter = counter;

        return copy;
    }

    const char *get_button_text() const
    {
        static char string[100];

        sprintf(string, "Value: %d", counter);

        return string;
    }

    int counter;
};

struct MyApplication : public Application<MyApplication, State, DefaultStyle>
{
    static State increment_counter(const State &state)
    {
        return state.with_counter(state.counter + 1);
    }

    static State decrement_counter(const State &state)
    {
        return state.with_counter(state.counter - 1);
    }

    static auto layout(const State &state)
    {
        return Rectangle
        {
            Button
            {
                position = SDL_Point { 120, 100 - state.counter * 5 },
                size = SDL_Point { 100, 30 },
                on_clicked = &decrement_counter,
                text = state.get_button_text()
            },

            Button
            {
                position = SDL_Point { 10, 100 + state.counter * 5 },
                size = SDL_Point { 100, 30 },
                on_clicked = &increment_counter,
                text = state.get_button_text()
            },

            position = SDL_Point { 100, 10 },
            size = SDL_Point { 50, 50 },
            color = SDL_Color { 0xFF, 0x00, 0x00, 0xFF },
        };
    }
};

int main(int argc, char **argv)
{
    QApplication application(argc, argv);

    MyApplication app;
    app.run();

    return 0;
}