with_label_widget.hpp

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// Copyright Take Vos 2021-2022.
// 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 "button_delegate.hpp"
#include "label_widget.hpp"
#include "../utility/utility.hpp"
#include "../algorithm/algorithm.hpp"
#include "../l10n/l10n.hpp"
#include "../observer/observer.hpp"
#include "../macros.hpp"
#include <memory>
#include <string>
#include <array>
#include <optional>
#include <future>
#include <coroutine>
 
hi_export_module(hikogui.widgets.with_label_widget);
 
hi_export namespace hi {
inline namespace v1 {
 
template<typename Context>
concept with_label_widget_attribute = label_widget_attribute<Context>;

template<std::derived_from<widget> ButtonWidget>
class with_label_widget : public widget {
public:
    using super = widget;
    using button_widget_type = ButtonWidget;
    using button_attributes_type = button_widget_type::attributes_type;
    using delegate_type = button_widget_type::delegate_type;
 
    struct attributes_type {
        observer<label> on_label = txt("on");

        observer<label> off_label = txt("off");

        observer<label> other_label = txt("other");

        observer<alignment> alignment = hi::alignment::top_left();
 
        attributes_type(attributes_type const&) noexcept = default;
        attributes_type(attributes_type&&) noexcept = default;
        attributes_type& operator=(attributes_type const&) noexcept = default;
        attributes_type& operator=(attributes_type&&) noexcept = default;
 
        template<with_label_widget_attribute... Attributes>
        explicit attributes_type(Attributes&&... attributes) noexcept
        {
            set_attributes<0>(std::forward<Attributes>(attributes)...);
        }
 
        template<size_t I>
        void set_attributes() noexcept
        {
        }
 
        template<size_t I, with_label_widget_attribute First, with_label_widget_attribute... Rest>
        void set_attributes(First&& first, Rest&&... rest) noexcept
        {
            if constexpr (forward_of<decltype(first), observer<hi::label>>) {
                if constexpr (I == 0) {
                    on_label = first;
                    off_label = first;
                    other_label = std::forward<First>(first);
                } else if constexpr (I == 1) {
                    other_label.reset();
                    off_label.reset();
                    off_label = std::forward<First>(first);
                } else if constexpr (I == 2) {
                    other_label = std::forward<First>(first);
                } else {
                    hi_static_no_default();
                }
                set_attributes<I + 1>(std::forward<Rest>(rest)...);
 
            } else if constexpr (forward_of<decltype(first), observer<hi::alignment>>) {
                alignment = std::forward<First>(first);
                set_attributes<I>(std::forward<Rest>(rest)...);
 
            } else {
                hi_static_no_default();
            }
        }
    };
 
    attributes_type attributes;
 
    template<typename... Args>
    [[nodiscard]] consteval static size_t num_default_delegate_arguments() noexcept
    {
        return button_widget_type::template num_default_delegate_arguments<Args...>();
    }
 
    template<size_t N, typename... Args>
    [[nodiscard]] static auto make_default_delegate(Args&&... args)
    {
        return button_widget_type::template make_default_delegate<N, Args...>(std::forward<Args>(args)...);
    }
 
    hi_call_right_arguments(static, make_attributes, attributes_type);
 
    with_label_widget(attributes_type attributes, std::shared_ptr<delegate_type> delegate) noexcept :
        super(), attributes(std::move(attributes))
    {
        _button_widget =
            std::make_unique<button_widget_type>(button_attributes_type{this->attributes.alignment}, std::move(delegate));
        _button_widget->set_parent(this);
 
        _on_label_widget = std::make_unique<label_widget>(this->attributes.on_label, this->attributes.alignment);
        _on_label_widget->set_parent(this);
 
        _off_label_widget = std::make_unique<label_widget>(this->attributes.off_label, this->attributes.alignment);
        _off_label_widget->set_parent(this);
 
        _other_label_widget = std::make_unique<label_widget>(this->attributes.other_label, this->attributes.alignment);
        _other_label_widget->set_parent(this);
 
        _button_widget_cbt = _button_widget->subscribe([&] {
            set_value(_button_widget->value());
 
            _on_label_widget->set_mode(value() == widget_value::on ? widget_mode::display : widget_mode::invisible);
            _off_label_widget->set_mode(value() == widget_value::off ? widget_mode::display : widget_mode::invisible);
            _other_label_widget->set_mode(value() == widget_value::other ? widget_mode::display : widget_mode::invisible);
 
            this->request_redraw();
            this->notifier();
        });
 
        _button_widget_cbt();
    }

    template<typename... Args>
    with_label_widget(Args&&... args) requires(num_default_delegate_arguments<Args...>() != 0)
        :
        with_label_widget(
            make_attributes<num_default_delegate_arguments<Args...>()>(std::forward<Args>(args)...),
            make_default_delegate<num_default_delegate_arguments<Args...>()>(std::forward<Args>(args)...))
    {
    }

    [[nodiscard]] box_constraints update_constraints() noexcept override
    {
        _layout = {};
 
        // Resolve as if in left-to-right mode, the grid will flip itself.
        auto const resolved_alignment = resolve(*attributes.alignment, true);
 
        _grid.clear();
        if (resolved_alignment == horizontal_alignment::left) {
            // button label
            _grid.add_cell(0, 0, grid_cell_type::button);
            _grid.add_cell(1, 0, grid_cell_type::label, true);
        } else if (resolved_alignment == horizontal_alignment::right) {
            // label button
            _grid.add_cell(0, 0, grid_cell_type::label, true);
            _grid.add_cell(1, 0, grid_cell_type::button);
        } else if (resolved_alignment == vertical_alignment::top) {
            // button
            // label
            _grid.add_cell(0, 0, grid_cell_type::button);
            _grid.add_cell(0, 1, grid_cell_type::label, true);
        } else if (resolved_alignment == vertical_alignment::bottom) {
            // label
            // button
            _grid.add_cell(0, 0, grid_cell_type::label, true);
            _grid.add_cell(0, 1, grid_cell_type::button);
        } else {
            hi_no_default("alignment is not allowed to be middle-center.");
        }
 
        for (auto& cell : _grid) {
            if (cell.value == grid_cell_type::button) {
                cell.set_constraints(_button_widget->update_constraints());
 
            } else if (cell.value == grid_cell_type::label) {
                auto const on_label_constraints = _on_label_widget->update_constraints();
                auto const off_label_constraints = _off_label_widget->update_constraints();
                auto const other_label_constraints = _other_label_widget->update_constraints();
                cell.set_constraints(max(on_label_constraints, off_label_constraints, other_label_constraints));
 
            } else {
                hi_no_default();
            }
        }
 
        return _grid.constraints(os_settings::left_to_right());
    }
 
    void set_layout(widget_layout const& context) noexcept override
    {
        if (compare_store(_layout, context)) {
            _grid.set_layout(context.shape, theme().baseline_adjustment());
        }
 
        for (auto const& cell : _grid) {
            if (cell.value == grid_cell_type::button) {
                _button_widget->set_layout(context.transform(cell.shape, transform_command::level));
 
            } else if (cell.value == grid_cell_type::label) {
                _on_label_widget->set_layout(context.transform(cell.shape));
                _off_label_widget->set_layout(context.transform(cell.shape));
                _other_label_widget->set_layout(context.transform(cell.shape));
 
            } else {
                hi_no_default();
            }
        }
    }
 
    void draw(draw_context const& context) noexcept override
    {
        if (mode() > widget_mode::invisible and overlaps(context, layout())) {
            for (auto const& cell : _grid) {
                if (cell.value == grid_cell_type::button) {
                    _button_widget->draw(context);
 
                } else if (cell.value == grid_cell_type::label) {
                    _on_label_widget->draw(context);
                    _off_label_widget->draw(context);
                    _other_label_widget->draw(context);
 
                } else {
                    hi_no_default();
                }
            }
        }
    }
 
    [[nodiscard]] generator<widget_intf&> children(bool include_invisible) noexcept override
    {
        co_yield *_button_widget;
        if (include_invisible or _on_label_widget->mode() > widget_mode::invisible) {
            co_yield *_on_label_widget;
        }
        if (include_invisible or _off_label_widget->mode() > widget_mode::invisible) {
            co_yield *_off_label_widget;
        }
        if (include_invisible or _other_label_widget->mode() > widget_mode::invisible) {
            co_yield *_other_label_widget;
        }
    }
 
    [[nodiscard]] hitbox hitbox_test(point2 position) const noexcept override
    {
        hi_axiom(loop::main().on_thread());
 
        if (mode() >= widget_mode::partial and layout().contains(position)) {
            // Accept the hitbox of the with_label_widget on behalf of the button_widget.
            return {_button_widget->id, _layout.elevation, hitbox_type::button};
        } else {
            return {};
        }
    }
protected:
    enum class grid_cell_type { button, label };
 
    grid_layout<grid_cell_type> _grid;
 
    std::unique_ptr<button_widget_type> _button_widget;
 
    std::unique_ptr<label_widget> _on_label_widget;
    std::unique_ptr<label_widget> _off_label_widget;
    std::unique_ptr<label_widget> _other_label_widget;
 
    callback<void()> _button_widget_cbt;
};
 
} // namespace v1
} // namespace hi::v1