#include "registration_thread.hpp"

#include <memory>
#include <unordered_set>
#include <unordered_map>

namespace {
struct RegistrationThread : std::enable_shared_from_this<RegistrationThread>
{
    Connection * connection_;
    std::string password_;
    std::string username_;
    std::string realname_;
    std::string nickname_;

    std::unordered_map<std::string, std::string> caps;
    std::unordered_set<std::string> outstanding;

    Connection::Handle<ConnectEvent> connect_handle_;
    Connection::Handle<IrcMsgEvent> message_handle_;

    enum class Stage
    {
        LsReply,
        AckReply,
    };

    Stage stage_;

    RegistrationThread(
        Connection * connection_,
        std::string password,
        std::string username,
        std::string realname,
        std::string nickname
    );

    auto on_connect() -> void;

    auto send_req() -> void;

    auto capack(IrcMsg const& msg) -> void;

    auto capls(IrcMsg const& msg) -> void;

    auto on_msg(IrcMsg const& msg) -> void;
};

RegistrationThread::RegistrationThread(
    Connection * connection,
    std::string password,
    std::string username,
    std::string realname,
    std::string nickname
)
    : connection_{connection}
    , password_{password}
    , username_{username}
    , realname_{realname}
    , nickname_{nickname}
    , stage_{Stage::LsReply}
{}

auto RegistrationThread::on_connect() -> void
{
    send_cap_ls(*connection_);
    send_pass(*connection_, password_);
    send_user(*connection_, username_, realname_);
    send_nick(*connection_, nickname_);

    connection_->remove_listener(connect_handle_);
}

auto RegistrationThread::send_req() -> void
{
    std::string request;
    char const* const want[] = {
        "extended-join",
        "account-notify",
        "draft/chathistory",
        "batch",
        "soju.im/no-implicit-names",
        "chghost",
        "setname",
        "account-tag",
        "solanum.chat/oper",
        "solanum.chat/identify-msg",
        "solanum.chat/realhost",
        "server-time",
        "invite-notify",
        "extended-join"
    };

    for (auto cap : want)
    {
        if (caps.contains(cap))
        {
            request.append(cap);
            request.push_back(' ');
            outstanding.insert(cap);
        }
    }
    if (not outstanding.empty())
    {
        request.pop_back();
        send_cap_req(*connection_, request);
        stage_ = Stage::AckReply;
    }
    else
    {
        send_cap_end(*connection_);
        connection_->remove_listener(message_handle_);
    }
}

auto RegistrationThread::capack(IrcMsg const& msg) -> void
{
    auto const n = msg.args.size();
    if (n >= 2 && "*" == msg.args[0] && "ACK" == msg.args[1])
    {
        auto in = std::istringstream{std::string{msg.args[2]}};
        std::for_each(
            std::istream_iterator<std::string>{in},
            std::istream_iterator<std::string>{},
            [this](std::string x) {
                outstanding.erase(x);
            }
        );
        if (outstanding.empty())
        {
            send_cap_end(*connection_);
            connection_->remove_listener(message_handle_);
        }
    }
}

auto RegistrationThread::capls(IrcMsg const& msg) -> void
{
    auto const n = msg.args.size();
    if (n >= 2 && "*" == msg.args[0] && "LS" == msg.args[1])
    {
        std::string_view const* kvs;
        bool last;

        if (3 == n)
        {
            kvs = &msg.args[2];
            last = true;
        }
        else if (4 == n && "*" == msg.args[2])
        {
            kvs = &msg.args[3];
            last = false;
        }
        else
        {
            return;
        }

        auto in = std::istringstream{std::string{*kvs}};

        std::for_each(
            std::istream_iterator<std::string>{in},
            std::istream_iterator<std::string>{},
            [this](std::string x) {
                auto const eq = x.find('=');
                if (eq == x.npos)
                {
                    caps.emplace(x, std::string{});
                }
                else
                {
                    caps.emplace(std::string{x, 0, eq}, std::string{x, eq+1, x.npos});
                }
            }
        );

        if (last)
        {
            send_req();
        }
    }
}

auto RegistrationThread::on_msg(IrcMsg const& msg) -> void
{
    switch (stage_)
    {
        case Stage::LsReply: capls(msg); return;
        case Stage::AckReply: capack(msg); return;
    }
}

} // namespace

auto registration_thread(
    Connection * connection,
    std::string password,
    std::string username,
    std::string realname,
    std::string nickname
) -> void
{
    auto const thread = std::make_shared<RegistrationThread>(connection, password, username, realname, nickname);
    thread->message_handle_ = connection->add_listener<IrcMsgEvent>([thread](IrcMsgEvent const& event)
    {
        if (IrcCommand::CAP == event.command)
        {
            thread->on_msg(event.irc);
        }
    });
    thread->connect_handle_ = connection->add_listener<ConnectEvent>([thread](ConnectEvent const&)
    {
        thread->on_connect();
    });
}