button_delegate.hpp

// Copyright Take Vos 2021.
// 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 "button_state.hpp"
#include <memory>
#include <functional>
 
namespace tt {
class abstract_button_widget;
 
class button_delegate {
public:
    using callback_ptr_type = std::shared_ptr<std::function<void()>>;
 
    virtual ~button_delegate() = default;
 
    virtual void init(abstract_button_widget &sender) noexcept {}
 
    virtual void deinit(abstract_button_widget &sender) noexcept {}
 
    virtual callback_ptr_type subscribe(abstract_button_widget &sender, callback_ptr_type const &callback) noexcept
    {
        return callback;
    }
 
    template<typename Callback>
    requires(std::is_invocable_v<Callback>) [[nodiscard]] callback_ptr_type
        subscribe(abstract_button_widget &sender, Callback &&callback) noexcept
    {
        return subscribe(sender, std::make_shared<std::function<void()>>(std::forward<Callback>(callback)));
    }
 
    virtual void unsubscribe(abstract_button_widget &sender, callback_ptr_type const &callback) noexcept {}
 
    virtual void activate(abstract_button_widget &sender) noexcept {};
 
    [[nodiscard]] virtual button_state state(abstract_button_widget const &sender) const noexcept
    {
        return button_state::off;
    }
};
 
} // namespace tt