/*
// Copyright (c) 2020 Intel Corporation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
*/
#include "password.hpp"

#include "xyz/openbmc_project/BIOSConfig/Common/error.hpp"
#include "xyz/openbmc_project/Common/error.hpp"

#include <boost/algorithm/hex.hpp>
#include <boost/asio.hpp>
#include <phosphor-logging/elog-errors.hpp>
#include <sdbusplus/asio/connection.hpp>
#include <sdbusplus/asio/object_server.hpp>

#include <fstream>
#include <iostream>

namespace bios_config_pwd
{
using namespace sdbusplus::xyz::openbmc_project::Common::Error;
using namespace sdbusplus::xyz::openbmc_project::BIOSConfig::Common::Error;

uint8_t
    Password::convertUnicode(const std::string& pwd,
                             std::array<uint16_t, maxPasswordLen>& unicodePwd)
{
    if (pwd.size() > unicodePwd.size())
    {
        phosphor::logging::log<phosphor::logging::level::DEBUG>(
            "password size exceeds unicodePwd array size");
        throw InternalFailure();
    }

    for (std::string::size_type i = 0; i < pwd.size(); i++)
    {
        unicodePwd[i] = pwd[i];
    }
    unicodePwd[pwd.size()] = 0;

    return (pwd.size() * sizeof(uint16_t) + sizeof(uint16_t));
}

bool Password::isMatch(const std::array<uint8_t, maxHashSize>& expected,
                       const std::array<uint8_t, maxSeedSize>& seed,
                       const std::string rawData, const std::string algo)
{
    phosphor::logging::log<phosphor::logging::level::ERR>("isMatch");

    if (algo == "SHA256")
    {
        std::vector<uint8_t> output(SHA256_DIGEST_LENGTH);
        unsigned int hashLen = 0;

        std::array<uint16_t, maxPasswordLen> unicodePwd = {0};
        uint8_t unicodePwdLength = convertUnicode(rawData, unicodePwd);

        if (HMAC(EVP_sha256(), seed.data(), seed.size(),
                 reinterpret_cast<const unsigned char*>(unicodePwd.data()),
                 unicodePwdLength, output.data(), &hashLen) == NULL)
        {
            phosphor::logging::log<phosphor::logging::level::ERR>(
                "Generate HMAC_SHA256 Integrity Check Value failed");
            throw InternalFailure();
        }

        int cmp;
        cmp = std::memcmp(output.data(), expected.data(),
                          output.size() * sizeof(uint8_t));
        if (cmp == 0)
        {
            return true;
        }
        else
        {
            return false;
        }
    }
    if (algo == "SHA384")
    {
        std::array<uint8_t, SHA384_DIGEST_LENGTH> output;
        unsigned int hashLen = 0;

        std::array<uint16_t, maxPasswordLen> unicodePwd = {0};
        uint8_t unicodePwdLength = convertUnicode(rawData, unicodePwd);

        if (HMAC(EVP_sha384(), seed.data(), seed.size(),
                 reinterpret_cast<const unsigned char*>(unicodePwd.data()),
                 unicodePwdLength, output.data(), &hashLen) == NULL)
        {
            phosphor::logging::log<phosphor::logging::level::ERR>(
                "Generate HMAC_SHA384 Integrity Check Value failed");
            throw InternalFailure();
        }

        int cmp;
        cmp = std::memcmp(output.data(), expected.data(),
                          output.size() * sizeof(uint8_t));
        if (cmp == 0)
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    return false;
}

void Password::verifyPassword(std::string userName, std::string currentPassword,
                              std::string newPassword)
{
    if (fs::exists(seedFile.c_str()))
    {
        std::array<uint8_t, maxHashSize> orgUsrPwdHash;
        std::array<uint8_t, maxHashSize> orgAdminPwdHash;
        std::array<uint8_t, maxSeedSize> seed;
        std::string hashAlgo = "";
        try
        {
            nlohmann::json json = nullptr;
            std::ifstream ifs(seedFile.c_str());
            if (ifs.is_open())
            {
                try
                {
                    json = nlohmann::json::parse(ifs, nullptr, false);
                }
                catch (const nlohmann::json::parse_error& e)
                {
                    phosphor::logging::log<phosphor::logging::level::ERR>(
                        e.what());
                    throw InternalFailure();
                }

                if (json.is_discarded())
                {
                    return;
                }
                orgUsrPwdHash = json["UserPwdHash"];
                orgAdminPwdHash = json["AdminPwdHash"];
                seed = json["Seed"];
                hashAlgo = json["HashAlgo"];
            }
            else
            {
                return;
            }
        }
        catch (nlohmann::detail::exception& e)
        {
            phosphor::logging::log<phosphor::logging::level::ERR>(e.what());
            throw InternalFailure();
        }
        if (userName == "AdminPassword")
        {
            if (!isMatch(orgAdminPwdHash, seed, currentPassword, hashAlgo))
            {
                throw InvalidCurrentPassword();
            }
        }
        else
        {
            if (!isMatch(orgUsrPwdHash, seed, currentPassword, hashAlgo))
            {
                throw InvalidCurrentPassword();
            }
        }
        if (hashAlgo == "SHA256")
        {
            std::array<uint16_t, maxPasswordLen> unicodePwd;
            uint8_t unicodePwdlength = 0;
            unsigned int mdLen = 0;
            unicodePwdlength = convertUnicode(newPassword, unicodePwd);
            mNewPwdHash.fill(0);

            if (HMAC(EVP_sha256(), seed.data(), seed.size(),
                     reinterpret_cast<const unsigned char*>(unicodePwd.data()),
                     unicodePwdlength, mNewPwdHash.data(), &mdLen) == NULL)
            {
                throw InternalFailure();
            }
        }
        if (hashAlgo == "SHA384")
        {
            std::array<uint16_t, maxPasswordLen> unicodePwd;
            uint8_t unicodePwdlength = 0;
            unsigned int mdLen = 0;
            unicodePwdlength = convertUnicode(newPassword, unicodePwd);
            mNewPwdHash.fill(0);

            if (HMAC(EVP_sha384(), seed.data(), seed.size(),
                     reinterpret_cast<const unsigned char*>(unicodePwd.data()),
                     unicodePwdlength, mNewPwdHash.data(), &mdLen) == NULL)
            {
                throw InternalFailure();
            }
        }
        return;
    }
    throw InternalFailure();
}
void Password::changePassword(std::string userName, std::string currentPassword,
                              std::string newPassword)
{
    phosphor::logging::log<phosphor::logging::level::DEBUG>(
        "BIOS config changePassword");
    verifyPassword(userName, currentPassword, newPassword);

    std::ifstream fs(seedFile.c_str());
    nlohmann::json json = nullptr;

    if (fs.is_open())
    {
        try
        {
            json = nlohmann::json::parse(fs, nullptr, false);
        }
        catch (const nlohmann::json::parse_error& e)
        {
            phosphor::logging::log<phosphor::logging::level::ERR>(e.what());
            throw InternalFailure();
        }

        if (json.is_discarded())
        {
            throw InternalFailure();
        }
        json["AdminPwdHash"] = mNewPwdHash;
        json["IsAdminPwdChanged"] = true;

        std::ofstream ofs(seedFile.c_str(), std::ios::out);
        const auto& writeData = json.dump();
        ofs << writeData;
        ofs.close();
    }
    else
    {
        phosphor::logging::log<phosphor::logging::level::DEBUG>(
            "Cannot open file stream");
        throw InternalFailure();
    }
}
Password::Password(sdbusplus::asio::object_server& objectServer,
                   std::shared_ptr<sdbusplus::asio::connection>& systemBus) :
    sdbusplus::xyz::openbmc_project::BIOSConfig::server::Password(
        *systemBus, objectPathPwd),
    objServer(objectServer), systemBus(systemBus)
{
    phosphor::logging::log<phosphor::logging::level::DEBUG>(
        "BIOS config password is runing");
    try
    {
        fs::path biosDir(BIOS_PERSIST_PATH);
        fs::create_directories(biosDir);
        seedFile = biosDir / biosSeedFile;
    }
    catch (const fs::filesystem_error& e)
    {
        phosphor::logging::log<phosphor::logging::level::ERR>(e.what());
        throw InternalFailure();
    }
}

} // namespace bios_config_pwd

int main()
{
    boost::asio::io_service io;
    auto systemBus = std::make_shared<sdbusplus::asio::connection>(io);

    systemBus->request_name(bios_config_pwd::servicePwd);
    sdbusplus::asio::object_server objectServer(systemBus);
    bios_config_pwd::Password password(objectServer, systemBus);

    io.run();
    return 0;
}