#include "connection.hpp"

#include "linebuffer.hpp"

#include <boost/log/trivial.hpp>

Connection::Connection(boost::asio::io_context & io)
: stream_{io}
, write_timer_{io, std::chrono::steady_clock::time_point::max()}
{
}

auto Connection::writer_immediate() -> void
{
    std::vector<boost::asio::const_buffer> buffers;
    buffers.reserve(write_strings_.size());
    for (auto const& elt : write_strings_)
    {
        buffers.push_back(boost::asio::buffer(elt));
    }
    boost::asio::async_write(
        stream_,
        buffers,
        [weak = weak_from_this()
        ,strings = std::move(write_strings_)
        ](boost::system::error_code const& error, std::size_t)
        {
            if (not error)
            {
                if (auto self = weak.lock())
                {
                    self->writer();
                }
            }
        });
    write_strings_.clear();
}

auto Connection::writer() -> void
{
    if (write_strings_.empty())
    {
        write_timer_.async_wait([weak = weak_from_this()](auto){
            if (auto self = weak.lock())
            {
                if (not self->write_strings_.empty())
                {
                    self->writer_immediate();
                }
            }
        });
    }
    else
    {
        writer_immediate();
    }
}

auto Connection::connect(
    boost::asio::io_context & io,
    std::string host,
    std::string port
) -> boost::asio::awaitable<void>
{
    using namespace std::placeholders;

    // keep connection alive while coroutine is active
    auto const self = shared_from_this();

    {
        auto resolver = boost::asio::ip::tcp::resolver{io};
        auto const endpoints = co_await resolver.async_resolve(host, port, boost::asio::use_awaitable);
        auto const endpoint = co_await boost::asio::async_connect(stream_, endpoints, boost::asio::use_awaitable);

        make_event<ConnectEvent>();
    }

    self->writer();
    for(LineBuffer buffer{32'768};;)
    {
        boost::system::error_code error;
        auto const n = co_await stream_.async_read_some(buffer.get_buffer(), boost::asio::redirect_error(boost::asio::use_awaitable, error));
        if (error)
        {
            break;
        }
        buffer.add_bytes(n, [this](char * line) {
            BOOST_LOG_TRIVIAL(debug) << "RECV: " << line;
            make_event<LineEvent>(line);
        });
    }

    make_event<DisconnectEvent>();
}

auto Connection::write_line(std::string message) -> void
{
    BOOST_LOG_TRIVIAL(debug) << "SEND: " << message;
    message += "\r\n";
    auto const need_cancel = write_strings_.empty();
    write_strings_.push_back(std::move(message));
    if (need_cancel)
    {
        write_timer_.cancel_one();
    }
}

auto Connection::close() -> void
{
    stream_.close();
}