radio_delegate.hpp

 
#pragma once
 
#include "../dispatch/dispatch.hpp"
#include "../observer/observer.hpp"
#include "../GUI/GUI.hpp"
#include "../utility/utility.hpp"
 
hi_export_module(hikogui.widgets.radio_delegate);
 
hi_export namespace hi { inline namespace v1 {
 
class radio_delegate {
public:
    virtual ~radio_delegate() = default;
 
    virtual void init(widget_intf const& sender) noexcept {}
 
    virtual void deinit(widget_intf const& sender) noexcept {}
 
    virtual void activate(widget_intf const& sender) noexcept {}
 
    [[nodiscard]] virtual widget_value state(widget_intf const& sender) const noexcept
    {
        return widget_value::off;
    }
 
    template<forward_of<void()> Func>
    [[nodiscard]] callback<void()> subscribe(Func&& func, callback_flags flags = callback_flags::synchronous) noexcept
    {
        return _notifier.subscribe(std::forward<Func>(func), flags);
    }
 
protected:
    notifier<void()> _notifier;
};
 
template<std::equality_comparable T>
class default_radio_delegate : public radio_delegate {
public:
    using value_type = T;
 
    observer<value_type> value;
    observer<value_type> on_value;
 
    template<forward_of<observer<value_type>> Value, forward_of<observer<value_type>> OnValue>
    default_radio_delegate(
        Value&& value,
        OnValue&& on_value) noexcept :
        value(std::forward<Value>(value)), on_value(std::forward<OnValue>(on_value))
    {
        // clang-format off
        _value_cbt = this->value.subscribe([&](auto...){ this->_notifier(); });
        _on_value_cbt = this->on_value.subscribe([&](auto...){ this->_notifier(); });
        // clang-format on
    }
 
    [[nodiscard]] widget_value state(widget_intf const& sender) const noexcept override
    {
        if (*value == *on_value) {
            return widget_value::on;
        } else {
            return widget_value::off;
        }
    }
 
    void activate(widget_intf const& sender) noexcept override
    {
        value = *on_value;
    }
private:
    callback<void(value_type)> _value_cbt;
    callback<void(value_type)> _on_value_cbt;
};
 
template<typename Value, typename OnValue>
default_radio_delegate(Value&&, OnValue&&) -> default_radio_delegate<observer_decay_t<Value>>;
 
}}