#include <boost/asio.hpp>
#include <iostream>
#include <optional>

class session: public std::enable_shared_from_this<session> {
  public:
    session(boost::asio::ip::tcp::socket&& socket) :
        socket(std::move(socket)) {}

    void start() {
        boost::asio::async_read_until(
            socket,
            streambuf,
            '\n',
            [self = shared_from_this()](
                boost::system::error_code error,
                std::size_t bytes_transferred) {
                std::cout << std::istream(&self->streambuf).rdbuf();
            });
    }

  private:
    boost::asio::ip::tcp::socket socket;
    boost::asio::streambuf streambuf;
};

class server {
  public:
    server(boost::asio::io_context& io_context, std::uint16_t port) :
        io_context(io_context),
        acceptor(
            io_context,
            boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), port)) {}

    void async_accept() {
        socket.emplace(io_context);

        acceptor.async_accept(*socket, [&](boost::system::error_code error) {
            std::make_shared<session>(std::move(*socket))->start();
            async_accept();
        });
    }

  private:
    boost::asio::io_context& io_context;
    boost::asio::ip::tcp::acceptor acceptor;
    std::optional<boost::asio::ip::tcp::socket> socket;
};

int main() {
    boost::asio::io_context io_context;
    server srv(io_context, 15001);
    srv.async_accept();
    io_context.run();
    return 0;
}