#include "systemd_handler.hpp"

#include "log.hpp"

#include <fmt/printf.h>

#include <boost/interprocess/file_mapping.hpp>
#include <boost/interprocess/mapped_region.hpp>

#include <regex>

namespace boot_time_monitor
{
namespace systemd
{

namespace btm = boot_time_monitor;

constexpr std::string_view kSystemdFirmwareTime = "FirmwareTimestampMonotonic";
constexpr std::string_view kSystemdLoaderTime = "LoaderTimestampMonotonic";
constexpr std::string_view kSystemdKernelTime = "KernelTimestampMonotonic";
constexpr std::string_view kSystemdInitRDTime = "InitRDTimestampMonotonic";
constexpr std::string_view kSystemdUserspaceTime =
    "UserspaceTimestampMonotonic";
constexpr std::string_view kSystemdFinishTime = "FinishTimestampMonotonic";

constexpr int64_t kMillisecondPerSecond = 1000;

struct SystemdTimestamp
{
    uint64_t firmware;
    uint64_t loader;
    uint64_t kernel;
    uint64_t initRD;
    uint64_t userspace;
    uint64_t finish;
};

struct SystemdDuration
{
    int64_t firmware;
    int64_t loader;
    int64_t kernel;
    int64_t initRD;
    int64_t userspace;
};

namespace
{
// How to calculate duration for each stage:
// https://github.com/systemd/systemd/blob/82b7bf8c1c8c6ded6f56b43998c803843a3b944b/src/analyze/analyze-time-data.c#L176-L186
// Special calculation for kernel duration:
// https://github.com/systemd/systemd/blob/82b7bf8c1c8c6ded6f56b43998c803843a3b944b/src/analyze/analyze-time-data.c#L84-L87
inline SystemdDuration CalculateSystemdDuration(SystemdTimestamp times)
{
    int64_t firmware = static_cast<int64_t>(times.firmware);
    int64_t loader = static_cast<int64_t>(times.loader);
    int64_t initRD = static_cast<int64_t>(times.initRD);
    int64_t userspace = static_cast<int64_t>(times.userspace);
    int64_t finish = static_cast<int64_t>(times.finish);
    SystemdDuration durations;
    durations.kernel = userspace;

    if (firmware != 0)
    {
        durations.firmware = firmware - loader;
    }

    if (loader != 0)
    {
        durations.loader = loader;
    }

    if (initRD > 0)
    {
        durations.kernel = initRD;
    }

    if (initRD != 0)
    {
        durations.initRD = userspace - initRD;
    }

    if (userspace != 0)
    {
        durations.userspace = finish - userspace;
    }
    return durations;
}

inline std::string convertName(std::string_view name)
{
    return std::regex_replace(std::string(name),
                              std::regex("TimestampMonotonic"), "");
}

} // namespace

Handler::Handler(std::shared_ptr<sdbusplus::asio::connection> conn,
                 std::shared_ptr<btm::api::IBoottimeApi> api) :
    mApi(std::move(api)), mBMCFinishTimer(conn->get_io_context())
{
    mBMCFinishTimer.expires_after(std::chrono::seconds(0));
    mBMCFinishTimer.async_wait(
        [this, &conn](const boost::system::error_code& ec) {
        CheckBmcFinish(ec, conn);
    });
}

void Handler::CheckBmcFinish(const boost::system::error_code& ec,
                             std::shared_ptr<sdbusplus::asio::connection>& conn)
{
    if (ec == boost::asio::error::operation_aborted)
    {
        fmt::print(stderr,
                   "[CheckBmcFinish] BmcFinishTimer is being "
                   "canceled, Error: {}\n",
                   ec.message().c_str());
        return;
    }

    if (ec)
    {
        fmt::print(stderr, "[CheckBmcFinish] Timer Error: {}\n",
                   ec.message().c_str());
        return;
    }

    // The raw pointer here is safe since it points to an existing instance
    // instead of allocating a memory space.
    // We can't use `std::share_ptr<uint64_t>(&times.firmware)` because the
    // `times` will free its space while `share_ptr` will also free the same
    // space again when this constructor completed. It will cause
    // `free(): double free detected` or `free(): invalid pointer` error.
    SystemdTimestamp times;
    std::array<std::pair<std::string, uint64_t*>, 6> bootTimestamp = {
        std::make_pair( // Firmware
            std::string(kSystemdFirmwareTime), &times.firmware),
        std::make_pair( // Loader
            std::string(kSystemdLoaderTime), &times.loader),
        std::make_pair( // Kernel
            std::string(kSystemdKernelTime), &times.kernel),
        std::make_pair( // InitRD
            std::string(kSystemdInitRDTime), &times.initRD),
        std::make_pair( // Userspace
            std::string(kSystemdUserspaceTime), &times.userspace),
        std::make_pair( // Finish
            std::string(kSystemdFinishTime), &times.finish)};

    for (const auto& timestamp : bootTimestamp)
    {
        auto method = conn->new_method_call(
            "org.freedesktop.systemd1",        // Systemd Service
            "/org/freedesktop/systemd1",       // Systemd Path
            "org.freedesktop.DBus.Properties", // Systemd Iface
            "Get");                            // Systemd Func
        method.append("org.freedesktop.systemd1.Manager",
                      std::string(timestamp.first));
        std::variant<uint64_t> result;
        try
        {
            conn->call(method).read(result);
        }
        catch (const sdbusplus::exception::SdBusError& e)
        {
            fmt::print(
                stderr,
                "[CheckBmcFinish] Can't get systemd property {}. ERROR={}\n",
                std::string(timestamp.first), e.what());
            // Restart the timer to keep polling the APML_ALERT status
            mBMCFinishTimer.expires_after(kCheckBmcFinishInterval);
            mBMCFinishTimer.async_wait(
                [this, &conn](const boost::system::error_code& ec) {
                CheckBmcFinish(ec, conn);
            });
        }
        *timestamp.second = std::get<uint64_t>(result);
    }

    // This daemon may start before the userspace is fully ready. So we need
    // to confirm if userspace is fully ready by checking `times.finish`
    // equals zero or not.
    if (times.finish == 0)
    {
        fmt::print(
            stderr,
            "[CheckBmcFinish] `FinishTimestampMonotonic` is not ready yet\n");
        mBMCFinishTimer.expires_after(kCheckBmcFinishInterval);
        mBMCFinishTimer.async_wait(
            [this, &conn](const boost::system::error_code& ec) {
            CheckBmcFinish(ec, conn);
        });
    }

    absl::Status status;
    SystemdDuration durations = CalculateSystemdDuration(times);
    status = mApi->SetNodesDurationByTag(
        btm::kBootTimeTagBMC, convertName(kSystemdFirmwareTime),
        durations.firmware / kMillisecondPerSecond);
    btm::log::LogIfError(status);
    status = mApi->SetNodesDurationByTag(
        btm::kBootTimeTagBMC, convertName(kSystemdLoaderTime),
        durations.loader / kMillisecondPerSecond);
    btm::log::LogIfError(status);
    status = mApi->SetNodesDurationByTag(
        btm::kBootTimeTagBMC, convertName(kSystemdKernelTime),
        durations.kernel / kMillisecondPerSecond);
    btm::log::LogIfError(status);
    status = mApi->SetNodesDurationByTag(
        btm::kBootTimeTagBMC, convertName(kSystemdInitRDTime),
        durations.initRD / kMillisecondPerSecond);
    btm::log::LogIfError(status);
    status = mApi->SetNodesDurationByTag(
        btm::kBootTimeTagBMC, convertName(kSystemdUserspaceTime),
        durations.userspace / kMillisecondPerSecond);
    btm::log::LogIfError(status);

#ifdef NPCM7XX_OR_NEWER
    // NPCM7XX or newer Nuvoton BMC has a register that starts counting from
    // SoC power on. Also uptime starts counting when kernel is up. Thus we
    // can get (Firmware + Loader) time by `value[SEC_CNT_ADDR] - uptime`.
    constexpr uint32_t SEC_CNT_ADDR = 0xF0801068;

    auto powerOnSec = readMem4Bytes(SEC_CNT_ADDR);
    auto upTimeMS = getUpTimeInMs();
    if (powerOnSec != std::nullopt && upTimeMS != std::nullopt)
    {
        status = mApi->SetNodesDurationByTag(
            btm::kBootTimeTagBMC, "FirmwarePlusLoader",
            powerOnSec.value() * 1000 - upTimeMS.value());
        btm::log::LogIfError(status);
    }
#endif

// BMC marks the boot process as `completed` automatically if we do *NOT* have
// external daemon to do so.
#ifdef AUTO_BMC_COMPLETE
    status = mApi->SetNodesCheckpointByTag(btm::kBootTimeTagBMC, "UserspaceEnd",
                                           0, 0);
    btm::log::LogIfError(status);
    status = mApi->NotifyNodesCompleteByTag(btm::kBootTimeTagBMC);
    btm::log::LogIfError(status);
#endif
}

#ifdef NPCM7XX_OR_NEWER
std::optional<uint32_t> Handler::readMem4Bytes(uint32_t target)
{
    // Typically the pageSize will be 4K/8K for 32 bit operating systems
    uint32_t pageSize = boost::interprocess::mapped_region::get_page_size();
    const uint32_t kPageMask = pageSize - 1;

    uint32_t pageOffset = target & (~kPageMask);
    uint32_t offsetInPage = target & kPageMask;

    // Map `/dev/mem` to a region.
    std::unique_ptr<boost::interprocess::file_mapping> fileMapping;
    std::unique_ptr<boost::interprocess::mapped_region> MappedRegion;
    try
    {
        fileMapping = std::make_unique<boost::interprocess::file_mapping>(
            "/dev/mem", boost::interprocess::read_only);
        // No need to unmap in the end.
        MappedRegion = std::make_unique<boost::interprocess::mapped_region>(
            *fileMapping, boost::interprocess::read_only, pageOffset,
            pageSize * 2);

        // MappedRegion->get_address() returns (void*) which needs to covert
        // into (char*) to make `+ offsetInPage` work.
        // Then converts it again into (uint32_t*) since we read 4 bytes.
        return *(reinterpret_cast<uint32_t*>(
            static_cast<char*>(MappedRegion->get_address()) + offsetInPage));
    }
    catch (const std::exception& e)
    {
        fmt::print(stderr, "[{}]: Throw exception: %s\n", __FUNCTION__,
                   e.what());
        return std::nullopt;
    }

    fmt::print(stderr, "[{}]: Shouldn't go to this line.\n", __FUNCTION__);
    return std::nullopt;
}

std::optional<int64_t> Handler::getUpTimeInMs()
{
    constexpr int32_t kMillisecondPerSecond = 1000;
    std::ifstream fin("/proc/uptime");
    if (!fin.is_open())
    {
        fmt::print(stderr, "[{}]: Can not read \"/proc/uptime\"\n",
                   __FUNCTION__);
        return std::nullopt;
    }
    double uptimeSec;
    fin >> uptimeSec;
    fin.close();

    return static_cast<int64_t>(uptimeSec * kMillisecondPerSecond);
}
#endif // NPCM7XX_OR_NEWER

} // namespace systemd
} // namespace boot_time_monitor