group.h

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/*
Copyright (c) 2026 MrXie1109
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
 
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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SOFTWARE.
*/
 
#pragma once
#include <atomic>
#include <condition_variable>
#include <exception>
#include <functional>
#include <mutex>
 
namespace console {
    class Group {
        int                             count_{0};    
        std::function<void()>           callback_;    
        bool                            done_{false}; 
        mutable std::mutex              mutex_;       
        mutable std::condition_variable cv_;          

        static void no_op() {}
 
    public:
        Group(size_t count = 0, std::function<void()> callback = no_op) :
            count_(count), callback_(callback) {}

        ~Group() {
            std::lock_guard<std::mutex> lock(mutex_);
            if (count_ != 0 || !done_) std::terminate();
        }

        void add(size_t count) {
            std::lock_guard<std::mutex> lock(mutex_);
            if (done_) std::terminate();
            count_ += count;
        }

        void done() {
            std::lock_guard<std::mutex> lock(mutex_);
            if (count_ <= 0) std::terminate();
            if (--count_ == 0) {
                done_ = true;
                callback_();
                cv_.notify_all();
            }
        }

        void wait() const {
            std::unique_lock<std::mutex> lock(mutex_);
            cv_.wait(lock, [this] { return count_ == 0 && done_; });
        }

        std::function<void()> callback() const {
            std::lock_guard<std::mutex> lock(mutex_);
            return callback_;
        }

        void connect(std::function<void()> callback) {
            std::lock_guard<std::mutex> lock(mutex_);
            callback_ = callback;
        }

        Group(const Group &) = delete;
        Group &operator=(const Group &) = delete;
        Group(Group &&) = delete;
        Group &operator=(Group &&) = delete;
    };
}