#include "registration.hpp"

#include "connection.hpp"
#include "ircmsg.hpp"
#include "sasl_mechanism.hpp"

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

Registration::Registration(
    const Settings &settings,
    std::shared_ptr<Client> client
)
    : settings_{settings}
    , client_{std::move(client)}
{
}

auto Registration::on_connect() -> void
{
    client_->get_connection().send_cap_ls();
    slot_ = client_->get_connection().sig_ircmsg.connect(
        [self = shared_from_this()](const auto cmd, auto &msg)
        {
            self->on_ircmsg(cmd, msg);
        }
    );

    if (not settings_.password.empty())
    {
        client_->get_connection().send_pass(settings_.password);
    }
    client_->get_connection().send_user(settings_.username, settings_.realname);
    client_->get_connection().send_nick(settings_.nickname);
}

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

    if (not settings_.sasl_mechanism.empty())
    {
        want.push_back("sasl");
    }

    for (const auto cap : want)
    {
        if (caps.contains(cap))
        {
            request.append(cap);
            request.push_back(' ');
            outstanding.insert(cap);
        }
    }

    if (not outstanding.empty())
    {
        request.pop_back();
        client_->get_connection().send_cap_req(request);
    }
    else
    {
        client_->get_connection().send_cap_end();
    }
}

auto Registration::on_msg_cap_ack(const IrcMsg &msg) -> void
{
    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())
    {

        if (settings_.sasl_mechanism.empty())
        {
            client_->get_connection().send_cap_end();
        }
        else
        {
            client_->start_sasl(std::make_unique<SaslPlain>(settings_.sasl_authcid, settings_.sasl_authzid, settings_.sasl_password));
        }
    }
}

auto Registration::on_msg_cap_ls(const IrcMsg &msg) -> void
{
    const std::string_view *kvs;
    bool last;

    if (3 == msg.args.size())
    {
        kvs = &msg.args[2];
        last = true;
    }
    else if (4 == msg.args.size() && "*" == 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) {
            const auto 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 Registration::start(
    const Settings &settings,
    std::shared_ptr<Client> client
) -> std::shared_ptr<Registration>
{
    const auto thread = std::make_shared<Registration>(std::move(settings), std::move(client));

    thread->slot_ = thread->client_->get_connection().sig_connect.connect([thread]() {
        thread->slot_.disconnect();
        thread->on_connect();
    });

    return thread;
}

auto Registration::randomize_nick() -> void
{
    std::string new_nick;
    new_nick += settings_.nickname.substr(0, 8);

    std::random_device rd;
    std::mt19937 gen{rd()};
    std::uniform_int_distribution<> distrib(0, 35);

    for (int i = 0; i < 8; ++i) {
        const auto x = distrib(gen);
        new_nick += x < 10 ? '0' + x : 'A' + (x-10);
    }

    client_->get_connection().send_nick(new_nick);
}

auto Registration::on_ircmsg(const IrcCommand cmd, const IrcMsg &msg) -> void
{
    switch (cmd)
    {
    default: break;

    case IrcCommand::CAP:
        if (msg.args.size() >= 2 && "LS" == msg.args[1]) {
            on_msg_cap_ls(msg);
        } else if (msg.args.size() >= 2 && "ACK" == msg.args[1]) {
            on_msg_cap_ack(msg);
        }
        break;

    case IrcCommand::ERR_NICKNAMEINUSE:
        randomize_nick();
        break;

    case IrcCommand::RPL_WELCOME:
        slot_.disconnect();
        break;

    case IrcCommand::RPL_SASLSUCCESS:
    case IrcCommand::ERR_SASLFAIL:
        client_->get_connection().send_cap_end();
        break;
    }
}