//
// Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
// Copyright (c) 2025 Mohammad Nejati
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// Official repository: https://github.com/boostorg/beast
//

//------------------------------------------------------------------------------
//
// Example: WebSocket server, asynchronous Unix domain sockets
//
//------------------------------------------------------------------------------

#include <boost/asio/dispatch.hpp>
#include <boost/asio/local/stream_protocol.hpp>
#include <boost/asio/strand.hpp>
#include <boost/beast/core.hpp>
#include <boost/beast/websocket.hpp>

#include <algorithm>
#include <cstdlib>
#include <iostream>
#include <memory>
#include <string>
#include <thread>
#include <vector>

#if defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)

namespace beast = boost::beast;                      // from <boost/beast.hpp>
namespace http = beast::http;                        // from <boost/beast/http.hpp>
namespace websocket = beast::websocket;              // from <boost/beast/websocket.hpp>
namespace net = boost::asio;                         // from <boost/asio.hpp>
using stream_protocol = net::local::stream_protocol; // from <boost/asio/local/stream_protocol.hpp>

//------------------------------------------------------------------------------

// Report a failure
void
fail(beast::error_code ec, char const* what)
{
    std::cerr << what << ": " << ec.message() << "\n";
}

// Echoes back all received WebSocket messages
class session : public std::enable_shared_from_this<session>
{
    websocket::stream<stream_protocol::socket> ws_;
    beast::flat_buffer buffer_;

public:
    // Take ownership of the socket
    explicit
    session(stream_protocol::socket&& socket)
        : ws_(std::move(socket))
    {
    }

    // Get on the correct executor
    void
    run()
    {
        // We need to be executing within a strand to perform async operations
        // on the I/O objects in this session. Although not strictly necessary
        // for single-threaded contexts, this example code is written to be
        // thread-safe by default.
        net::dispatch(ws_.get_executor(),
            beast::bind_front_handler(
                &session::on_run,
                shared_from_this()));
    }

    // Start the asynchronous operation
    void
    on_run()
    {
        // Set suggested timeout settings for the websocket
        ws_.set_option(
            websocket::stream_base::timeout::suggested(
                beast::role_type::server));

        // Set a decorator to change the Server of the handshake
        ws_.set_option(websocket::stream_base::decorator(
            [](websocket::response_type& res)
            {
                res.set(http::field::server,
                    std::string(BOOST_BEAST_VERSION_STRING) +
                        " websocket-server-async-local");
            }));
        // Accept the websocket handshake
        ws_.async_accept(
            beast::bind_front_handler(
                &session::on_accept,
                shared_from_this()));
    }

    void
    on_accept(beast::error_code ec)
    {
        if(ec)
            return fail(ec, "accept");

        // Read a message
        do_read();
    }

    void
    do_read()
    {
        // Read a message into our buffer
        ws_.async_read(
            buffer_,
            beast::bind_front_handler(
                &session::on_read,
                shared_from_this()));
    }

    void
    on_read(
        beast::error_code ec,
        std::size_t bytes_transferred)
    {
        boost::ignore_unused(bytes_transferred);

        // This indicates that the session was closed
        if(ec == websocket::error::closed)
            return;

        if(ec)
            return fail(ec, "read");

        // Echo the message
        ws_.text(ws_.got_text());
        ws_.async_write(
            buffer_.data(),
            beast::bind_front_handler(
                &session::on_write,
                shared_from_this()));
    }

    void
    on_write(
        beast::error_code ec,
        std::size_t bytes_transferred)
    {
        boost::ignore_unused(bytes_transferred);

        if(ec)
            return fail(ec, "write");

        // Clear the buffer
        buffer_.consume(buffer_.size());

        // Do another read
        do_read();
    }
};

//------------------------------------------------------------------------------

// Accepts incoming connections and launches the sessions
class listener : public std::enable_shared_from_this<listener>
{
    net::io_context& ioc_;
    stream_protocol::acceptor acceptor_;

public:
    listener(
        net::io_context& ioc,
        stream_protocol::endpoint endpoint)
        : ioc_(ioc)
        , acceptor_(ioc, std::move(endpoint))
    {
    }

    // Start accepting incoming connections
    void
    run()
    {
        do_accept();
    }

private:
    void
    do_accept()
    {
        // The new connection gets its own strand
        acceptor_.async_accept(
            net::make_strand(ioc_),
            beast::bind_front_handler(
                &listener::on_accept,
                shared_from_this()));
    }

    void
    on_accept(beast::error_code ec, stream_protocol::socket socket)
    {
        if(ec)
        {
            fail(ec, "accept");
            return;
        }
        else
        {
            // Create the session and run it
            std::make_shared<session>(std::move(socket))->run();
        }

        // Accept another connection
        do_accept();
    }
};

//------------------------------------------------------------------------------

int main(int argc, char* argv[])
{
    try
    {
        // Check command line arguments.
        if (argc != 3)
        {
            std::cerr <<
                "Usage: websocket-server-async-local <path> <threads>\n" <<
                "Example:\n" <<
                "    websocket-server-async-local /tmp/ws.sock 1\n";
            return EXIT_FAILURE;
        }
        auto const path = argv[1];
        auto const threads = std::max<int>(1, std::atoi(argv[2]));

        // The io_context is required for all I/O
        net::io_context ioc{threads};

        // Remove previous binding
        std::remove(path);

        // Create and launch a listening port
        std::make_shared<listener>(ioc, stream_protocol::endpoint{path})->run();

        // Run the I/O service on the requested number of threads
        std::vector<std::thread> v;
        v.reserve(threads - 1);
        for(auto i = threads - 1; i > 0; --i)
            v.emplace_back(
            [&ioc]
            {
                ioc.run();
            });
        ioc.run();

        return EXIT_SUCCESS;
    }
    catch(std::exception const& e)
    {
        std::cerr << e.what() << std::endl;
        return EXIT_FAILURE;
    }
}

#else

int
main(int, char*[])
{
    std::cerr <<
        "Local sockets not available on this platform" << std::endl;
    return EXIT_FAILURE;
}

#endif