//
// 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_WEBSOCKET_IMPL_HANDSHAKE_HPP
#define BOOST_BEAST_WEBSOCKET_IMPL_HANDSHAKE_HPP

#include <boost/beast/websocket/impl/stream_impl.hpp>
#include <boost/beast/websocket/detail/type_traits.hpp>
#include <boost/beast/http/empty_body.hpp>
#include <boost/beast/http/message.hpp>
#include <boost/beast/http/read.hpp>
#include <boost/beast/http/write.hpp>
#include <boost/beast/core/async_op_base.hpp>
#include <boost/beast/core/stream_traits.hpp>
#include <boost/asio/coroutine.hpp>
#include <boost/assert.hpp>
#include <boost/throw_exception.hpp>
#include <memory>

namespace boost {
namespace beast {
namespace websocket {

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

// send the upgrade request and process the response
//
template<class NextLayer, bool deflateSupported>
template<class Handler>
class stream<NextLayer, deflateSupported>::handshake_op
    : public beast::stable_async_op_base<Handler,
        beast::executor_type<stream>>
    , public net::coroutine
{
    struct data
    {
        // VFALCO This really should be two separate
        //        composed operations, to save on memory
        http::request<http::empty_body> req;
        response_type res;
    };

    boost::weak_ptr<impl_type> wp_;
    detail::sec_ws_key_type key_;
    response_type* res_p_;
    data& d_;

public:
    template<class Handler_, class Decorator>
    handshake_op(
        Handler_&& h,
        boost::shared_ptr<impl_type> const& sp,
        response_type* res_p,
        string_view host, string_view target,
        Decorator const& decorator)
        : stable_async_op_base<Handler,
            beast::executor_type<stream>>(
                std::forward<Handler_>(h),
                    sp->stream.get_executor())
        , wp_(sp)
        , res_p_(res_p)
        , d_(beast::allocate_stable<data>(*this))
    {
        d_.req = sp->build_request(
            key_, host, target, decorator);
        sp->reset(); // VFALCO I don't like this
    }

    void
    operator()(
        error_code ec = {},
        std::size_t bytes_used = 0,
        bool cont = true)
    {
        boost::ignore_unused(bytes_used);
        auto sp = wp_.lock();
        if(! sp)
            return this->invoke(cont,
                net::error::operation_aborted);
        auto& impl = *sp;
        BOOST_ASIO_CORO_REENTER(*this)
        {
            impl.change_status(status::handshake);
            impl.update_timer(this->get_executor());

            // write HTTP request
            impl.do_pmd_config(d_.req);
            BOOST_ASIO_CORO_YIELD
            http::async_write(impl.stream,
                d_.req, std::move(*this));
            if(impl.check_stop_now(ec))
                goto upcall;

            // read HTTP response
            BOOST_ASIO_CORO_YIELD
            http::async_read(impl.stream,
                impl.rd_buf, d_.res,
                    std::move(*this));
            if(impl.check_stop_now(ec))
                goto upcall;

            // success
            impl.reset_idle();
            impl.on_response(d_.res, key_, ec);
            if(res_p_)
                swap(d_.res, *res_p_);

        upcall:
            this->invoke(cont ,ec);
        }
    }
};

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

template<class NextLayer, bool deflateSupported>
template<class RequestDecorator>
void
stream<NextLayer, deflateSupported>::
do_handshake(
    response_type* res_p,
    string_view host,
    string_view target,
    RequestDecorator const& decorator,
    error_code& ec)
{
    response_type res;
    impl_->change_status(status::handshake);
    impl_->reset();
    detail::sec_ws_key_type key;
    {
        auto const req = impl_->build_request(
            key, host, target, decorator);
        this->impl_->do_pmd_config(req);
        http::write(impl_->stream, req, ec);
    }
    if(ec)
        return;
    http::read(next_layer(), impl_->rd_buf, res, ec);
    if(ec)
        return;
    impl_->on_response(res, key, ec);
    if(res_p)
        *res_p = std::move(res);
}

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

template<class NextLayer, bool deflateSupported>
template<class HandshakeHandler>
BOOST_ASIO_INITFN_RESULT_TYPE(
    HandshakeHandler, void(error_code))
stream<NextLayer, deflateSupported>::
async_handshake(string_view host,
    string_view target,
        HandshakeHandler&& handler)
{
    static_assert(is_async_stream<next_layer_type>::value,
        "AsyncStream requirements not met");
    BOOST_BEAST_HANDLER_INIT(
        HandshakeHandler, void(error_code));
    handshake_op<BOOST_ASIO_HANDLER_TYPE(
        HandshakeHandler, void(error_code))>(
            std::move(init.completion_handler),
                impl_, nullptr, host, target,
                    &default_decorate_req)();
    return init.result.get();
}

template<class NextLayer, bool deflateSupported>
template<class HandshakeHandler>
BOOST_ASIO_INITFN_RESULT_TYPE(
    HandshakeHandler, void(error_code))
stream<NextLayer, deflateSupported>::
async_handshake(response_type& res,
    string_view host,
        string_view target,
            HandshakeHandler&& handler)
{
    static_assert(is_async_stream<next_layer_type>::value,
        "AsyncStream requirements not met");
    BOOST_BEAST_HANDLER_INIT(
        HandshakeHandler, void(error_code));
    handshake_op<BOOST_ASIO_HANDLER_TYPE(
        HandshakeHandler, void(error_code))>(
            std::move(init.completion_handler),
                impl_, &res, host, target,
                    &default_decorate_req)();
    return init.result.get();
}

template<class NextLayer, bool deflateSupported>
template<class RequestDecorator, class HandshakeHandler>
BOOST_ASIO_INITFN_RESULT_TYPE(
    HandshakeHandler, void(error_code))
stream<NextLayer, deflateSupported>::
async_handshake_ex(string_view host,
    string_view target,
        RequestDecorator const& decorator,
            HandshakeHandler&& handler)
{
    static_assert(is_async_stream<next_layer_type>::value,
        "AsyncStream requirements not met");
    static_assert(detail::is_request_decorator<
            RequestDecorator>::value,
        "RequestDecorator requirements not met");
    BOOST_BEAST_HANDLER_INIT(
        HandshakeHandler, void(error_code));
    handshake_op<BOOST_ASIO_HANDLER_TYPE(
        HandshakeHandler, void(error_code))>(
            std::move(init.completion_handler),
                impl_, nullptr, host, target,
                    decorator)();
    return init.result.get();
}

template<class NextLayer, bool deflateSupported>
template<class RequestDecorator, class HandshakeHandler>
BOOST_ASIO_INITFN_RESULT_TYPE(
    HandshakeHandler, void(error_code))
stream<NextLayer, deflateSupported>::
async_handshake_ex(response_type& res,
    string_view host,
        string_view target,
            RequestDecorator const& decorator,
                HandshakeHandler&& handler)
{
    static_assert(is_async_stream<next_layer_type>::value,
        "AsyncStream requirements not met");
    static_assert(detail::is_request_decorator<
            RequestDecorator>::value,
        "RequestDecorator requirements not met");
    BOOST_BEAST_HANDLER_INIT(
        HandshakeHandler, void(error_code));
    handshake_op<BOOST_ASIO_HANDLER_TYPE(
        HandshakeHandler, void(error_code))>(
            std::move(init.completion_handler),
                impl_, &res, host, target,
                    decorator)();
    return init.result.get();
}

template<class NextLayer, bool deflateSupported>
void
stream<NextLayer, deflateSupported>::
handshake(string_view host,
    string_view target)
{
    static_assert(is_sync_stream<next_layer_type>::value,
        "SyncStream requirements not met");
    error_code ec;
    handshake(
        host, target, ec);
    if(ec)
        BOOST_THROW_EXCEPTION(system_error{ec});
}

template<class NextLayer, bool deflateSupported>
void
stream<NextLayer, deflateSupported>::
handshake(response_type& res,
    string_view host,
        string_view target)
{
    static_assert(is_sync_stream<next_layer_type>::value,
        "SyncStream requirements not met");
    error_code ec;
    handshake(res, host, target, ec);
    if(ec)
        BOOST_THROW_EXCEPTION(system_error{ec});
}

template<class NextLayer, bool deflateSupported>
template<class RequestDecorator>
void
stream<NextLayer, deflateSupported>::
handshake_ex(string_view host,
    string_view target,
        RequestDecorator const& decorator)
{
    static_assert(is_sync_stream<next_layer_type>::value,
        "SyncStream requirements not met");
    static_assert(detail::is_request_decorator<
            RequestDecorator>::value,
        "RequestDecorator requirements not met");
    error_code ec;
    handshake_ex(host, target, decorator, ec);
    if(ec)
        BOOST_THROW_EXCEPTION(system_error{ec});
}

template<class NextLayer, bool deflateSupported>
template<class RequestDecorator>
void
stream<NextLayer, deflateSupported>::
handshake_ex(response_type& res,
    string_view host,
        string_view target,
            RequestDecorator const& decorator)
{
    static_assert(is_sync_stream<next_layer_type>::value,
        "SyncStream requirements not met");
    static_assert(detail::is_request_decorator<
            RequestDecorator>::value,
        "RequestDecorator requirements not met");
    error_code ec;
    handshake_ex(res, host, target, decorator, ec);
    if(ec)
        BOOST_THROW_EXCEPTION(system_error{ec});
}

template<class NextLayer, bool deflateSupported>
void
stream<NextLayer, deflateSupported>::
handshake(string_view host,
    string_view target, error_code& ec)
{
    static_assert(is_sync_stream<next_layer_type>::value,
        "SyncStream requirements not met");
    do_handshake(nullptr,
        host, target, &default_decorate_req, ec);
}

template<class NextLayer, bool deflateSupported>
void
stream<NextLayer, deflateSupported>::
handshake(response_type& res,
    string_view host,
        string_view target,
            error_code& ec)
{
    static_assert(is_sync_stream<next_layer_type>::value,
        "SyncStream requirements not met");
    do_handshake(&res,
        host, target, &default_decorate_req, ec);
}

template<class NextLayer, bool deflateSupported>
template<class RequestDecorator>
void
stream<NextLayer, deflateSupported>::
handshake_ex(string_view host,
    string_view target,
        RequestDecorator const& decorator,
            error_code& ec)
{
    static_assert(is_sync_stream<next_layer_type>::value,
        "SyncStream requirements not met");
    static_assert(detail::is_request_decorator<
            RequestDecorator>::value,
        "RequestDecorator requirements not met");
    do_handshake(nullptr,
        host, target, decorator, ec);
}

template<class NextLayer, bool deflateSupported>
template<class RequestDecorator>
void
stream<NextLayer, deflateSupported>::
handshake_ex(response_type& res,
    string_view host,
        string_view target,
            RequestDecorator const& decorator,
                error_code& ec)
{
    static_assert(is_sync_stream<next_layer_type>::value,
        "SyncStream requirements not met");
    static_assert(detail::is_request_decorator<
            RequestDecorator>::value,
        "RequestDecorator requirements not met");
    do_handshake(&res,
        host, target, decorator, ec);
}

} // websocket
} // beast
} // boost

#endif