selection_widget.hpp

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// Copyright Take Vos 2020-2022.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include "widget.hpp"
#include "label_widget.hpp"
#include "overlay_widget.hpp"
#include "scroll_widget.hpp"
#include "row_column_widget.hpp"
#include "menu_button_widget.hpp"
#include "selection_delegate.hpp"
#include "../observer.hpp"
#include <memory>
#include <string>
#include <array>
#include <optional>
#include <future>
 
namespace hi { inline namespace v1 {
 
template<typename Context>
concept selection_widget_attribute = label_widget_attribute<Context>;
 
class selection_widget final : public widget {
public:
    using super = widget;
    using delegate_type = selection_delegate;
 
    std::shared_ptr<delegate_type> delegate;
 
    observer<label> off_label;
 
    observer<alignment> alignment = hi::alignment::middle_flush();
 
    observer<semantic_text_style> text_style = semantic_text_style::label;
 
    ~selection_widget();
 
    selection_widget(widget *parent, std::shared_ptr<delegate_type> delegate) noexcept;
 
    selection_widget(
        widget *parent,
        std::shared_ptr<delegate_type> delegate,
        selection_widget_attribute auto&& first_attribute,
        selection_widget_attribute auto&&...attributes) noexcept :
        selection_widget(parent, std::move(delegate))
    {
        set_attributes(hi_forward(first_attribute), hi_forward(attributes)...);
    }
 
    template<
        different_from<std::shared_ptr<delegate_type>> Value,
        forward_of<observer<std::vector<std::pair<observer_decay_t<Value>, label>>>> OptionList,
        selection_widget_attribute... Attributes>
    selection_widget(
        widget *parent,
        Value&& value,
        OptionList&& option_list,
        Attributes&&...attributes) noexcept requires requires
    {
        make_default_selection_delegate(hi_forward(value), hi_forward(option_list));
    } :
        selection_widget(
            parent,
            make_default_selection_delegate(hi_forward(value), hi_forward(option_list)),
            hi_forward(attributes)...)
    {
    }
 
    template<
        different_from<std::shared_ptr<delegate_type>> Value,
        forward_of<observer<std::vector<std::pair<observer_decay_t<Value>, label>>>> OptionList,
        forward_of<observer<observer_decay_t<Value>>> OffValue,
        selection_widget_attribute... Attributes>
    selection_widget(
        widget *parent,
        Value&& value,
        OptionList&& option_list,
        OffValue&& off_value,
        Attributes&&...attributes) noexcept requires requires
    {
        make_default_selection_delegate(hi_forward(value), hi_forward(option_list), hi_forward(off_value));
    } :
        selection_widget(
            parent,
            make_default_selection_delegate(hi_forward(value), hi_forward(option_list), hi_forward(off_value)),
            hi_forward(attributes)...)
    {
    }
 
    [[nodiscard]] generator<widget const &> children(bool include_invisible) const noexcept override;
    [[nodiscard]] box_constraints update_constraints() noexcept override;
    void set_layout(widget_layout const& context) noexcept override;
    void draw(draw_context const& context) noexcept override;
    bool handle_event(gui_event const& event) noexcept override;
    [[nodiscard]] hitbox hitbox_test(point2i position) const noexcept override;
    [[nodiscard]] bool accepts_keyboard_focus(keyboard_focus_group group) const noexcept override;
    [[nodiscard]] color focus_color() const noexcept override;
private:
    notifier<>::callback_token _delegate_cbt;
    std::atomic<bool> _notification_from_delegate = true;
 
    std::unique_ptr<label_widget> _current_label_widget;
    box_constraints _current_label_constraints;
    box_shape _current_label_shape;
 
    std::unique_ptr<label_widget> _off_label_widget;
    box_constraints _off_label_constraints;
    box_shape _off_label_shape;
 
    aarectanglei _left_box_rectangle;
 
    glyph_ids _chevrons_glyph;
    aarectanglei _chevrons_rectangle;
 
    bool _selecting = false;
    bool _has_options = false;
 
    std::unique_ptr<overlay_widget> _overlay_widget;
    box_constraints _overlay_constraints;
    box_shape _overlay_shape;
 
    vertical_scroll_widget *_scroll_widget = nullptr;
    column_widget *_column_widget = nullptr;
 
    decltype(off_label)::callback_token _off_label_cbt;
    std::vector<menu_button_widget *> _menu_button_widgets;
    std::vector<notifier<>::callback_token> _menu_button_tokens;
 
    void set_attributes() noexcept {}
    void set_attributes(label_widget_attribute auto&& first, label_widget_attribute auto&&...rest) noexcept
    {
        if constexpr (forward_of<decltype(first), observer<hi::label>>) {
            off_label = hi_forward(first);
        } else if constexpr (forward_of<decltype(first), observer<hi::alignment>>) {
            alignment = hi_forward(first);
        } else if constexpr (forward_of<decltype(first), observer<hi::semantic_text_style>>) {
            text_style = hi_forward(first);
        } else {
            hi_static_no_default();
        }
 
        set_attributes(hi_forward(rest)...);
    }
 
    [[nodiscard]] menu_button_widget const *get_first_menu_button() const noexcept;
    [[nodiscard]] menu_button_widget const *get_selected_menu_button() const noexcept;
    void start_selecting() noexcept;
    void stop_selecting() noexcept;
    void repopulate_options() noexcept;
    void draw_outline(draw_context const& context) noexcept;
    void draw_left_box(draw_context const& context) noexcept;
    void draw_chevrons(draw_context const& context) noexcept;
};
 
}} // namespace hi::v1