#pragma once

#include "ref.hpp"

#include <boost/signals2.hpp>

#include <memory>
#include <optional>
#include <string>
#include <string_view>
#include <variant>

class SaslMechanism
{
public:
    struct NoReply {};
    struct Failure {};

    using StepResult = std::variant<std::string, NoReply, Failure>;

    virtual ~SaslMechanism() {}

    virtual auto mechanism_name() const -> std::string = 0;
    virtual auto step(std::string_view msg) -> StepResult = 0;
    virtual auto is_complete() const -> bool = 0;
};

class SaslPlain final : public SaslMechanism
{
    std::string authcid_;
    std::string authzid_;
    std::string password_;
    bool complete_;

public:
    SaslPlain(std::string authcid, std::string authzid, std::string password)
    : authcid_{std::move(authcid)}
    , authzid_{std::move(authzid)}
    , password_{std::move(password)}
    , complete_{false}
    {}

    auto mechanism_name() const -> std::string override
    {
        return "PLAIN";
    }

    auto step(std::string_view msg) -> StepResult override;

    auto is_complete() const -> bool override
    {
        return complete_;
    }
};

class SaslExternal final : public SaslMechanism
{
    std::string authzid_;
    bool complete_;

public:
    SaslExternal(std::string authzid)
    : authzid_{std::move(authzid)}
    , complete_{false}
    {}

    auto mechanism_name() const -> std::string override
    {
        return "EXTERNAL";
    }

    auto step(std::string_view msg) -> StepResult override;

    auto is_complete() const -> bool override
    {
        return complete_;
    }
};


class SaslEcdsa final : public SaslMechanism
{
    std::string message1_;
    Ref<EVP_PKEY> key_;
    int stage_;

public:
    SaslEcdsa(std::string authcid, std::string authzid, Ref<EVP_PKEY> key)
        : message1_{std::move(authcid)}
        , key_{std::move(key)}
        , stage_{0}
    {
        if (not authzid.empty()) {
            message1_.push_back(0);
            message1_.append(authzid);
        }
    }

    auto mechanism_name() const -> std::string override
    {
        return "ECDSA-NIST256P-CHALLENGE";
    }

    auto step(std::string_view msg) -> StepResult override;

    auto is_complete() const -> bool override
    {
        return stage_ == 2;;
    }
};