text_field_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 "text_field_delegate.hpp"
#include "widget.hpp"
#include "label_widget.hpp"
#include "scroll_widget.hpp"
#include "../l10n/l10n.hpp"
#include "../macros.hpp"
#include <memory>
#include <string>
#include <array>
#include <optional>
#include <future>
#include <coroutine>
 
hi_export_module(hikogui.widgets.text_field_widget);
 
hi_export namespace hi { inline namespace v1 {
 
template<typename Context>
concept text_field_widget_attribute = text_widget_attribute<Context>;

class text_field_widget : public widget {
public:
    using delegate_type = text_field_delegate;
    using super = widget;
 
    std::shared_ptr<delegate_type> delegate;

    observer<bool> continues = false;

    observer<alignment> alignment = alignment::middle_flush();
 
    virtual ~text_field_widget()
    {
        hi_assert_not_null(delegate);
        delegate->deinit(*this);
    }
 
    text_field_widget(std::shared_ptr<delegate_type> delegate) noexcept :
        super(), delegate(std::move(delegate)), _text()
    {
        hi_assert_not_null(this->delegate);
        _delegate_cbt = this->delegate->subscribe([&] {
            ++global_counter<"text_field_widget:delegate:layout">;
            process_event({gui_event_type::window_relayout});
        });
        this->delegate->init(*this);
 
        _scroll_widget = std::make_unique<scroll_widget<axis::none>>();
        _scroll_widget->set_parent(this);
 
        _text_widget = &_scroll_widget->emplace<text_widget>(_text, alignment);
        _text_widget->set_mode(widget_mode::partial);
 
        _error_label_widget = std::make_unique<label_widget>(_error_label, alignment::top_left());
        _error_label_widget->set_parent(this);
 
        _continues_cbt = continues.subscribe([&](auto...) {
            ++global_counter<"text_field_widget:continues:constrain">;
            process_event({gui_event_type::window_reconstrain});
        });
        _text_cbt = _text.subscribe([&](auto...) {
            ++global_counter<"text_field_widget:text:constrain">;
            process_event({gui_event_type::window_reconstrain});
        });
        _error_label_cbt = _error_label.subscribe([&](auto const& new_value) {
            ++global_counter<"text_field_widget:error_label:constrain">;
            process_event({gui_event_type::window_reconstrain});
        });
    }
 
    template<text_field_widget_attribute... Attributes>
    text_field_widget(
        std::shared_ptr<delegate_type> delegate,
        Attributes&&...attributes) noexcept :
        text_field_widget(std::move(delegate))
    {
        set_attributes(std::forward<Attributes>(attributes)...);
    }

    template<incompatible_with<std::shared_ptr<delegate_type>> Value, text_field_widget_attribute... Attributes>
    text_field_widget(
        Value&& value,
        Attributes&&...attributes) noexcept requires requires
    {
        make_default_text_field_delegate(std::forward<Value>(value));
    } : text_field_widget(make_default_text_field_delegate(std::forward<Value>(value)), std::forward<Attributes>(attributes)...) {}

    [[nodiscard]] generator<widget_intf&> children(bool include_invisible) noexcept override
    {
        if (_scroll_widget) {
            co_yield *_scroll_widget;
        }
        if (_error_label_widget) {
            co_yield *_error_label_widget;
        }
    }
 
    [[nodiscard]] box_constraints update_constraints() noexcept override
    {
        hi_assert_not_null(delegate);
        hi_assert_not_null(_error_label_widget);
        hi_assert_not_null(_scroll_widget);
 
        if (_text_widget->focus()) {
            // Update the optional error value from the string conversion when the text-widget has keyboard focus.
            _error_label = delegate->validate(*this, *_text);
 
        } else {
            // When field is not focused, simply follow the observed_value.
            revert(false);
        }
 
        _layout = {};
        _scroll_constraints = _scroll_widget->update_constraints();
 
        auto const scroll_width = 100;
        auto const box_size = extent2{
            _scroll_constraints.margins.left() + scroll_width + _scroll_constraints.margins.right(),
            _scroll_constraints.margins.top() + _scroll_constraints.preferred.height() + _scroll_constraints.margins.bottom()};
 
        auto size = box_size;
        auto margins = theme().margin();
        if (_error_label->empty()) {
            _error_label_widget->set_mode(widget_mode::invisible);
            _error_label_constraints = _error_label_widget->update_constraints();
 
        } else {
            _error_label_widget->set_mode(widget_mode::display);
            _error_label_constraints = _error_label_widget->update_constraints();
            inplace_max(size.width(), _error_label_constraints.preferred.width());
            size.height() += _error_label_constraints.margins.top() + _error_label_constraints.preferred.height();
            inplace_max(margins.left(), _error_label_constraints.margins.left());
            inplace_max(margins.right(), _error_label_constraints.margins.right());
            inplace_max(margins.bottom(), _error_label_constraints.margins.bottom());
        }
 
        // The alignment of a text-field is not based on the text-widget due to the intermediate scroll widget.
        auto const resolved_alignment = resolve_mirror(*alignment, os_settings::left_to_right());
 
        return {size, size, size, resolved_alignment, margins};
    }
    void set_layout(widget_layout const& context) noexcept override
    {
        if (compare_store(_layout, context)) {
            auto const scroll_size = extent2{
                context.width(),
                _scroll_constraints.margins.top() + _scroll_constraints.preferred.height() +
                    _scroll_constraints.margins.bottom()};
 
            auto const scroll_rectangle = aarectangle{point2{0, context.height() - scroll_size.height()}, scroll_size};
            _scroll_shape = box_shape{_scroll_constraints, scroll_rectangle, theme().baseline_adjustment()};
 
            if (_error_label_widget->mode() > widget_mode::invisible) {
                auto const error_label_rectangle =
                    aarectangle{0, 0, context.rectangle().width(), _error_label_constraints.preferred.height()};
                _error_label_shape = box_shape{_error_label_constraints, error_label_rectangle, theme().baseline_adjustment()};
            }
        }
 
        if (_error_label_widget->mode() > widget_mode::invisible) {
            _error_label_widget->set_layout(context.transform(_error_label_shape));
        }
        _scroll_widget->set_layout(context.transform(_scroll_shape));
    }
    void draw(draw_context const& context) noexcept override
    {
        if (mode() > widget_mode::invisible and overlaps(context, layout())) {
            draw_background_box(context);
 
            _scroll_widget->draw(context);
            _error_label_widget->draw(context);
        }
    }
    bool handle_event(gui_event const& event) noexcept override
    {
        switch (event.type()) {
        case gui_event_type::gui_cancel:
            if (mode() >= widget_mode::partial) {
                revert(true);
                return true;
            }
            break;
 
        case gui_event_type::gui_activate:
            if (mode() >= widget_mode::partial) {
                commit(true);
                return super::handle_event(event);
            }
            break;
 
        default:;
        }
 
        return super::handle_event(event);
    }
    hitbox hitbox_test(point2 position) const noexcept override
    {
        if (mode() >= widget_mode::partial) {
            auto r = hitbox{};
            r = _scroll_widget->hitbox_test_from_parent(position, r);
            r = _error_label_widget->hitbox_test_from_parent(position, r);
            return r;
        } else {
            return hitbox{};
        }
    }
    [[nodiscard]] bool accepts_keyboard_focus(keyboard_focus_group group) const noexcept override
    {
        if (mode() >= widget_mode::partial) {
            return _scroll_widget->accepts_keyboard_focus(group);
        } else {
            return false;
        }
    }
    [[nodiscard]] color focus_color() const noexcept override
    {
        if (mode() >= widget_mode::partial) {
            if (not _error_label->empty()) {
                auto const error_style = theme().text_style_set()[{phrasing::error}];
                return error_style.color();
            } else if (_text_widget->focus()) {
                return theme().accent_color();
            } else if (phase() == widget_phase::hover) {
                return theme().border_color(_layout.layer + 1);
            } else {
                return theme().border_color(_layout.layer);
            }
 
        } else {
            return theme().border_color(_layout.layer - 1);
        }
    }
private:
    std::unique_ptr<scroll_widget<axis::none>> _scroll_widget;
    box_constraints _scroll_constraints;
    box_shape _scroll_shape;

    text_widget *_text_widget = nullptr;

    observer<gstring> _text;

    observer<label> _error_label;
    std::unique_ptr<label_widget> _error_label_widget;
    box_constraints _error_label_constraints;
    box_shape _error_label_shape;
 
    callback<void()> _delegate_cbt;
    callback<void(bool)> _continues_cbt;
    callback<void(gstring)> _text_cbt;
    callback<void(label)> _error_label_cbt;
 
    void set_attributes() noexcept {}
 
    template<text_field_widget_attribute First, text_field_widget_attribute... Rest>
    void set_attributes(First&& first, Rest&&...rest) noexcept
    {
        if constexpr (forward_of<First, observer<hi::alignment>>) {
            alignment = std::forward<First>(first);
        } else {
            hi_static_no_default();
        }
 
        set_attributes(std::forward<Rest>(rest)...);
    }
 
    void revert(bool force) noexcept
    {
        hi_assert_not_null(delegate);
        _text = delegate->text(*this);
        _error_label = label{};
    }
    void commit(bool force) noexcept
    {
        hi_axiom(loop::main().on_thread());
        hi_assert_not_null(delegate);
 
        if (*continues or force) {
            auto text = *_text;
 
            if (delegate->validate(*this, text).empty()) {
                // text is valid.
                delegate->set_text(*this, text);
            }
 
            // After commit get the canonical text to display from the delegate.
            _text = delegate->text(*this);
            _error_label = label{};
        }
    }
    void draw_background_box(draw_context const& context) const noexcept
    {
        auto const outline = _scroll_shape.rectangle;
 
        auto const corner_radii = hi::corner_radii(0.0f, 0.0f, theme().rounding_radius<float>(), theme().rounding_radius<float>());
        context.draw_box(layout(), outline, background_color(), corner_radii);
 
        auto const line = line_segment(get<0>(outline), get<1>(outline));
        context.draw_line(layout(), translate3{0.0f, 0.5f, 0.1f} * line, theme().border_width(), focus_color());
    }
};
 
}} // namespace hi::v1