//
// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
//
// 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
//

#ifndef BOOST_BEAST_EXAMPLE_COMMON_SSL_STREAM_HPP
#define BOOST_BEAST_EXAMPLE_COMMON_SSL_STREAM_HPP

// This include is necessary to work with `ssl::stream` and `boost::beast::websocket::stream`
#include <boost/beast/websocket/ssl.hpp>

#include <boost/asio/ip/tcp.hpp>
#include <boost/asio/ssl/stream.hpp>
#include <cstddef>
#include <memory>
#include <type_traits>
#include <utility>

/** C++11 enabled SSL socket wrapper

    This wrapper provides an interface identical to `boost::asio::ssl::stream`,
    with the following additional properties:
    
    @li Satisfies @b MoveConstructible
    
    @li Satisfies @b MoveAssignable
   
    @li Constructible from a moved socket.
*/
template<class NextLayer>
class ssl_stream
    : public boost::asio::ssl::stream_base
{
    // only works for boost::asio::ip::tcp::socket
    // for now because of the move limitations
    static_assert(std::is_same<NextLayer, boost::asio::ip::tcp::socket>::value,
        "NextLayer requirements not met");

    using stream_type = boost::asio::ssl::stream<NextLayer>;

    std::unique_ptr<stream_type> p_;
    boost::asio::ssl::context* ctx_;

public:
    /// The native handle type of the SSL stream.
    using native_handle_type = typename stream_type::native_handle_type;

    /// Structure for use with deprecated impl_type.
    using impl_struct = typename stream_type::impl_struct;

    /// The type of the next layer.
    using next_layer_type = typename stream_type::next_layer_type;

    /// The type of the lowest layer.
    using lowest_layer_type = typename stream_type::lowest_layer_type;

    /// The type of the executor associated with the object.
    using executor_type = typename stream_type::executor_type;

    ssl_stream(
        boost::asio::ip::tcp::socket socket,
        boost::asio::ssl::context& ctx)
        : p_(new stream_type{
            socket.get_executor().context(), ctx})
        , ctx_(&ctx)
    {
        p_->next_layer() = std::move(socket);
    }

    ssl_stream(ssl_stream&& other)
        : p_(new stream_type(
            other.get_executor().context(), *other.ctx_))
        , ctx_(other.ctx_)
    {
        using std::swap;
        swap(p_, other.p_);
    }

    ssl_stream& operator=(ssl_stream&& other)
    {
        std::unique_ptr<stream_type> p(new stream_type{
            other.get_executor().context(), other.ctx_});
        using std::swap;
        swap(p_, p);
        swap(p_, other.p_);
        ctx_ = other.ctx_;
        return *this;
    }

    executor_type
    get_executor() noexcept
    {
        return p_->get_executor();
    }

    native_handle_type
    native_handle()
    {
        return p_->native_handle();
    }

    next_layer_type const&
    next_layer() const
    {
        return p_->next_layer();
    }

    next_layer_type&
    next_layer()
    {
        return p_->next_layer();
    }

    lowest_layer_type&
    lowest_layer()
    {
        return p_->lowest_layer();
    }

    lowest_layer_type const&
    lowest_layer() const
    {
        return p_->lowest_layer();
    }

    void
    set_verify_mode(boost::asio::ssl::verify_mode v)
    {
        p_->set_verify_mode(v);
    }

    boost::system::error_code
    set_verify_mode(boost::asio::ssl::verify_mode v,
        boost::system::error_code& ec)
    {
        return p_->set_verify_mode(v, ec);
    }

    void
    set_verify_depth(int depth)
    {
        p_->set_verify_depth(depth);
    }

    boost::system::error_code
    set_verify_depth(
        int depth, boost::system::error_code& ec)
    {
        return p_->set_verify_depth(depth, ec);
    }

    template<class VerifyCallback>
    void
    set_verify_callback(VerifyCallback callback)
    {
        p_->set_verify_callback(callback);
    }

    template<class VerifyCallback>
    boost::system::error_code
    set_verify_callback(VerifyCallback callback,
        boost::system::error_code& ec)
    {
        return p_->set_verify_callback(callback, ec);
    }

    void
    handshake(handshake_type type)
    {
        p_->handshake(type);
    }

    boost::system::error_code
    handshake(handshake_type type,
        boost::system::error_code& ec)
    {
        return p_->handshake(type, ec);
    }

    template<class ConstBufferSequence>
    void
    handshake(
        handshake_type type, ConstBufferSequence const& buffers)
    {
        p_->handshake(type, buffers);
    }

    template<class ConstBufferSequence>
    boost::system::error_code
    handshake(handshake_type type,
        ConstBufferSequence const& buffers,
            boost::system::error_code& ec)
    {
        return p_->handshake(type, buffers, ec);
    }

    template<class HandshakeHandler>
    BOOST_ASIO_INITFN_RESULT_TYPE(HandshakeHandler,
        void(boost::system::error_code))
    async_handshake(handshake_type type,
        BOOST_ASIO_MOVE_ARG(HandshakeHandler) handler)
    {
        return p_->async_handshake(type,
            BOOST_ASIO_MOVE_CAST(HandshakeHandler)(handler));
    }

    template<class ConstBufferSequence, class BufferedHandshakeHandler>
    BOOST_ASIO_INITFN_RESULT_TYPE(BufferedHandshakeHandler,
        void (boost::system::error_code, std::size_t))
    async_handshake(handshake_type type, ConstBufferSequence const& buffers,
        BOOST_ASIO_MOVE_ARG(BufferedHandshakeHandler) handler)
    {
        return p_->async_handshake(type, buffers,
            BOOST_ASIO_MOVE_CAST(BufferedHandshakeHandler)(handler));
    }

    void
    shutdown()
    {
        p_->shutdown();
    }

    boost::system::error_code
    shutdown(boost::system::error_code& ec)
    {
        return p_->shutdown(ec);
    }

    template<class ShutdownHandler>
    BOOST_ASIO_INITFN_RESULT_TYPE(ShutdownHandler,
        void (boost::system::error_code))
    async_shutdown(BOOST_ASIO_MOVE_ARG(ShutdownHandler) handler)
    {
        return p_->async_shutdown(
            BOOST_ASIO_MOVE_CAST(ShutdownHandler)(handler));
    }

    template<class ConstBufferSequence>
    std::size_t
    write_some(ConstBufferSequence const& buffers)
    {
        return p_->write_some(buffers);
    }

    template<class ConstBufferSequence>
    std::size_t
    write_some(ConstBufferSequence const& buffers,
        boost::system::error_code& ec)
    {
        return p_->write_some(buffers, ec);
    }

    template<class ConstBufferSequence, class WriteHandler>
    BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler,
        void (boost::system::error_code, std::size_t))
    async_write_some(ConstBufferSequence const& buffers,
        BOOST_ASIO_MOVE_ARG(WriteHandler) handler)
    {
        return p_->async_write_some(buffers,
            BOOST_ASIO_MOVE_CAST(WriteHandler)(handler));
    }

    template<class MutableBufferSequence>
    std::size_t
    read_some(MutableBufferSequence const& buffers)
    {
        return p_->read_some(buffers);
    }

    template<class MutableBufferSequence>
    std::size_t
    read_some(MutableBufferSequence const& buffers,
        boost::system::error_code& ec)
    {
        return p_->read_some(buffers, ec);
    }

    template<class MutableBufferSequence, class ReadHandler>
    BOOST_ASIO_INITFN_RESULT_TYPE(ReadHandler,
        void(boost::system::error_code, std::size_t))
    async_read_some(MutableBufferSequence const& buffers,
        BOOST_ASIO_MOVE_ARG(ReadHandler) handler)
    {
        return p_->async_read_some(buffers,
            BOOST_ASIO_MOVE_CAST(ReadHandler)(handler));
    }

    template<class SyncStream>
    friend
    void
    teardown(boost::beast::websocket::role_type,
        ssl_stream<SyncStream>& stream,
            boost::system::error_code& ec);

    template<class AsyncStream, class TeardownHandler>
    friend
    void
    async_teardown(boost::beast::websocket::role_type,
        ssl_stream<AsyncStream>& stream, TeardownHandler&& handler);
};

// These hooks are used to inform boost::beast::websocket::stream on
// how to tear down the connection as part of the WebSocket
// protocol specifications

template<class SyncStream>
inline
void
teardown(
    boost::beast::websocket::role_type role,
    ssl_stream<SyncStream>& stream,
    boost::system::error_code& ec)
{
    // Just forward it to the wrapped ssl::stream
    using boost::beast::websocket::teardown;
    teardown(role, *stream.p_, ec);
}

template<class AsyncStream, class TeardownHandler>
inline
void
async_teardown(
    boost::beast::websocket::role_type role,
    ssl_stream<AsyncStream>& stream,
    TeardownHandler&& handler)
{
    // Just forward it to the wrapped ssl::stream
    using boost::beast::websocket::async_teardown;
    async_teardown(role,
        *stream.p_, std::forward<TeardownHandler>(handler));
}

#endif