/**
 * Copyright © 2019 IBM 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 "repository.hpp"

#include <sys/stat.h>

#include <fstream>
#include <phosphor-logging/log.hpp>
#include <xyz/openbmc_project/Common/File/error.hpp>

namespace openpower
{
namespace pels
{

namespace fs = std::filesystem;
using namespace phosphor::logging;
namespace file_error = sdbusplus::xyz::openbmc_project::Common::File::Error;

/**
 * @brief Returns the amount of space the file uses on disk.
 *
 * This is different than just the regular size of the file.
 *
 * @param[in] file - The file to get the size of
 *
 * @return size_t The disk space the file uses
 */
size_t getFileDiskSize(const std::filesystem::path& file)
{
    constexpr size_t statBlockSize = 512;
    struct stat statData;
    auto rc = stat(file.c_str(), &statData);
    if (rc != 0)
    {
        auto e = errno;
        std::string msg = "call to stat() failed on " + file.native() +
                          " with errno " + std::to_string(e);
        log<level::ERR>(msg.c_str());
        abort();
    }

    return statData.st_blocks * statBlockSize;
}

Repository::Repository(const std::filesystem::path& basePath, size_t repoSize,
                       size_t maxNumPELs) :
    _logPath(basePath / "logs"),
    _maxRepoSize(repoSize), _maxNumPELs(maxNumPELs)
{
    if (!fs::exists(_logPath))
    {
        fs::create_directories(_logPath);
    }

    restore();
}

void Repository::restore()
{
    for (auto& dirEntry : fs::directory_iterator(_logPath))
    {
        try
        {
            if (!fs::is_regular_file(dirEntry.path()))
            {
                continue;
            }

            std::ifstream file{dirEntry.path()};
            std::vector<uint8_t> data{std::istreambuf_iterator<char>(file),
                                      std::istreambuf_iterator<char>()};
            file.close();

            PEL pel{data};
            if (pel.valid())
            {
                // If the host hasn't acked it, reset the host state so
                // it will get sent up again.
                if (pel.hostTransmissionState() == TransmissionState::sent)
                {
                    pel.setHostTransmissionState(TransmissionState::newPEL);
                    try
                    {
                        write(pel, dirEntry.path());
                    }
                    catch (std::exception& e)
                    {
                        log<level::ERR>(
                            "Failed to save PEL after updating host state",
                            entry("PELID=0x%X", pel.id()));
                    }
                }

                PELAttributes attributes{dirEntry.path(),
                                         getFileDiskSize(dirEntry.path()),
                                         pel.privateHeader().creatorID(),
                                         pel.userHeader().severity(),
                                         pel.userHeader().actionFlags(),
                                         pel.hostTransmissionState(),
                                         pel.hmcTransmissionState()};

                using pelID = LogID::Pel;
                using obmcID = LogID::Obmc;
                _pelAttributes.emplace(
                    LogID(pelID(pel.id()), obmcID(pel.obmcLogID())),
                    attributes);
            }
            else
            {
                log<level::ERR>(
                    "Found invalid PEL file while restoring.  Removing.",
                    entry("FILENAME=%s", dirEntry.path().c_str()));
                fs::remove(dirEntry.path());
            }
        }
        catch (std::exception& e)
        {
            log<level::ERR>("Hit exception while restoring PEL File",
                            entry("FILENAME=%s", dirEntry.path().c_str()),
                            entry("ERROR=%s", e.what()));
        }
    }
}

std::string Repository::getPELFilename(uint32_t pelID, const BCDTime& time)
{
    char name[50];
    sprintf(name, "%.2X%.2X%.2X%.2X%.2X%.2X%.2X%.2X_%.8X", time.yearMSB,
            time.yearLSB, time.month, time.day, time.hour, time.minutes,
            time.seconds, time.hundredths, pelID);
    return std::string{name};
}

void Repository::add(std::unique_ptr<PEL>& pel)
{
    pel->setHostTransmissionState(TransmissionState::newPEL);
    pel->setHMCTransmissionState(TransmissionState::newPEL);

    auto path = _logPath / getPELFilename(pel->id(), pel->commitTime());

    write(*(pel.get()), path);

    PELAttributes attributes{path,
                             getFileDiskSize(path),
                             pel->privateHeader().creatorID(),
                             pel->userHeader().severity(),
                             pel->userHeader().actionFlags(),
                             pel->hostTransmissionState(),
                             pel->hmcTransmissionState()};

    using pelID = LogID::Pel;
    using obmcID = LogID::Obmc;
    _pelAttributes.emplace(LogID(pelID(pel->id()), obmcID(pel->obmcLogID())),
                           attributes);

    processAddCallbacks(*pel);
}

void Repository::write(const PEL& pel, const fs::path& path)
{
    std::ofstream file{path, std::ios::binary};

    if (!file.good())
    {
        // If this fails, the filesystem is probably full so it isn't like
        // we could successfully create yet another error log here.
        auto e = errno;
        fs::remove(path);
        log<level::ERR>("Unable to open PEL file for writing",
                        entry("ERRNO=%d", e), entry("PATH=%s", path.c_str()));
        throw file_error::Open();
    }

    auto data = pel.data();
    file.write(reinterpret_cast<const char*>(data.data()), data.size());

    if (file.fail())
    {
        // Same note as above about not being able to create an error log
        // for this case even if we wanted.
        auto e = errno;
        file.close();
        fs::remove(path);
        log<level::ERR>("Unable to write PEL file", entry("ERRNO=%d", e),
                        entry("PATH=%s", path.c_str()));
        throw file_error::Write();
    }
}

void Repository::remove(const LogID& id)
{
    auto pel = findPEL(id);
    if (pel != _pelAttributes.end())
    {
        log<level::DEBUG>("Removing PEL from repository",
                          entry("PEL_ID=0x%X", pel->first.pelID.id),
                          entry("OBMC_LOG_ID=%d", pel->first.obmcID.id));
        fs::remove(pel->second.path);
        _pelAttributes.erase(pel);

        processDeleteCallbacks(pel->first.pelID.id);
    }
    else
    {
        log<level::DEBUG>("Could not find PEL to remove",
                          entry("PEL_ID=0x%X", id.pelID.id),
                          entry("OBMC_LOG_ID=%d", id.obmcID.id));
    }
}

std::optional<std::vector<uint8_t>> Repository::getPELData(const LogID& id)
{
    auto pel = findPEL(id);
    if (pel != _pelAttributes.end())
    {
        std::ifstream file{pel->second.path.c_str()};
        if (!file.good())
        {
            auto e = errno;
            log<level::ERR>("Unable to open PEL file", entry("ERRNO=%d", e),
                            entry("PATH=%s", pel->second.path.c_str()));
            throw file_error::Open();
        }

        std::vector<uint8_t> data{std::istreambuf_iterator<char>(file),
                                  std::istreambuf_iterator<char>()};
        return data;
    }

    return std::nullopt;
}

std::optional<sdbusplus::message::unix_fd> Repository::getPELFD(const LogID& id)
{
    auto pel = findPEL(id);
    if (pel != _pelAttributes.end())
    {
        FILE* fp = fopen(pel->second.path.c_str(), "rb");

        if (fp == nullptr)
        {
            auto e = errno;
            log<level::ERR>("Unable to open PEL File", entry("ERRNO=%d", e),
                            entry("PATH=%s", pel->second.path.c_str()));
            throw file_error::Open();
        }

        // Must leave the file open here.  It will be closed by sdbusplus
        // when it sends it back over D-Bus.

        return fileno(fp);
    }
    return std::nullopt;
}

void Repository::for_each(ForEachFunc func) const
{
    for (const auto& [id, attributes] : _pelAttributes)
    {
        std::ifstream file{attributes.path};

        if (!file.good())
        {
            auto e = errno;
            log<level::ERR>("Repository::for_each: Unable to open PEL file",
                            entry("ERRNO=%d", e),
                            entry("PATH=%s", attributes.path.c_str()));
            continue;
        }

        std::vector<uint8_t> data{std::istreambuf_iterator<char>(file),
                                  std::istreambuf_iterator<char>()};
        file.close();

        PEL pel{data};

        try
        {
            if (func(pel))
            {
                break;
            }
        }
        catch (std::exception& e)
        {
            log<level::ERR>("Repository::for_each function exception",
                            entry("ERROR=%s", e.what()));
        }
    }
}

void Repository::processAddCallbacks(const PEL& pel) const
{
    for (auto& [name, func] : _addSubscriptions)
    {
        try
        {
            func(pel);
        }
        catch (std::exception& e)
        {
            log<level::ERR>("PEL Repository add callback exception",
                            entry("NAME=%s", name.c_str()),
                            entry("ERROR=%s", e.what()));
        }
    }
}

void Repository::processDeleteCallbacks(uint32_t id) const
{
    for (auto& [name, func] : _deleteSubscriptions)
    {
        try
        {
            func(id);
        }
        catch (std::exception& e)
        {
            log<level::ERR>("PEL Repository delete callback exception",
                            entry("NAME=%s", name.c_str()),
                            entry("ERROR=%s", e.what()));
        }
    }
}

std::optional<std::reference_wrapper<const Repository::PELAttributes>>
    Repository::getPELAttributes(const LogID& id) const
{
    auto pel = findPEL(id);
    if (pel != _pelAttributes.end())
    {
        return pel->second;
    }

    return std::nullopt;
}

void Repository::setPELHostTransState(uint32_t pelID, TransmissionState state)
{
    LogID id{LogID::Pel{pelID}};
    auto attr = std::find_if(_pelAttributes.begin(), _pelAttributes.end(),
                             [&id](const auto& a) { return a.first == id; });

    if ((attr != _pelAttributes.end()) && (attr->second.hostState != state))
    {
        PELUpdateFunc func = [state](PEL& pel) {
            pel.setHostTransmissionState(state);
        };

        try
        {
            updatePEL(attr->second.path, func);

            attr->second.hostState = state;
        }
        catch (std::exception& e)
        {
            log<level::ERR>("Unable to update PEL host transmission state",
                            entry("PATH=%s", attr->second.path.c_str()),
                            entry("ERROR=%s", e.what()));
        }
    }
}

void Repository::setPELHMCTransState(uint32_t pelID, TransmissionState state)
{
    LogID id{LogID::Pel{pelID}};
    auto attr = std::find_if(_pelAttributes.begin(), _pelAttributes.end(),
                             [&id](const auto& a) { return a.first == id; });

    if ((attr != _pelAttributes.end()) && (attr->second.hmcState != state))
    {
        PELUpdateFunc func = [state](PEL& pel) {
            pel.setHMCTransmissionState(state);
        };

        try
        {
            updatePEL(attr->second.path, func);

            attr->second.hmcState = state;
        }
        catch (std::exception& e)
        {
            log<level::ERR>("Unable to update PEL HMC transmission state",
                            entry("PATH=%s", attr->second.path.c_str()),
                            entry("ERROR=%s", e.what()));
        }
    }
}

void Repository::updatePEL(const fs::path& path, PELUpdateFunc updateFunc)
{
    std::ifstream file{path};
    std::vector<uint8_t> data{std::istreambuf_iterator<char>(file),
                              std::istreambuf_iterator<char>()};
    file.close();

    PEL pel{data};

    if (pel.valid())
    {
        updateFunc(pel);

        write(pel, path);
    }
    else
    {
        throw std::runtime_error(
            "Unable to read a valid PEL when trying to update it");
    }
}

} // namespace pels
} // namespace openpower