/*
 * Copyright (C) 2008-2019 TrinityCore <https://www.trinitycore.org/>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef __TRINITY_SECRETMGR_H__
#define __TRINITY_SECRETMGR_H__

#include "BigNumber.h"
#include "Common.h"
#include "LogCommon.h"
#include "Optional.h"
#include <array>
#include <mutex>
#include <string>

enum Secrets : uint32
{
    SECRET_TOTP_MASTER_KEY = 0,

    // only add new indices right above this line
    NUM_SECRETS
};

class TC_SHARED_API SecretMgr
{
    private:
        SecretMgr() {}
        ~SecretMgr() {}

    public:
        SecretMgr(SecretMgr const&) = delete;
        static SecretMgr* instance();

        struct Secret
        {
            public:
                explicit operator bool() const { return (state == PRESENT); }
                BigNumber const& operator*() const { return value; }
                BigNumber const* operator->() const { return &value; }
                bool IsAvailable() const { return (state != NOT_LOADED_YET) && (state != LOAD_FAILED); }

            private:
                std::mutex lock;
                enum { NOT_LOADED_YET, LOAD_FAILED, NOT_PRESENT, PRESENT } state = NOT_LOADED_YET;
                BigNumber value;

            friend class SecretMgr;
        };

        void Initialize();
        Secret const& GetSecret(Secrets i);

    private:
        void AttemptLoad(Secrets i, LogLevel errorLevel, std::unique_lock<std::mutex> const&);
        Optional<std::string> AttemptTransition(Secrets i, Optional<BigNumber> const& newSecret, Optional<BigNumber> const& oldSecret, bool hadOldSecret) const;

        std::array<Secret, NUM_SECRETS> _secrets;
};

#define sSecretMgr SecretMgr::instance()

#endif