#include <arpa/inet.h>
#include <fcntl.h>
#include <limits.h>
#include <linux/i2c-dev.h>
#include <linux/i2c.h>
#include <mapper.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <systemd/sd-bus.h>
#include <unistd.h>

#include <algorithm>
#include <app/channel.hpp>
#include <app/watchdog.hpp>
#include <apphandler.hpp>
#include <array>
#include <cstddef>
#include <cstdint>
#include <filesystem>
#include <fstream>
#include <ipmid/api.hpp>
#include <ipmid/types.hpp>
#include <ipmid/utils.hpp>
#include <memory>
#include <nlohmann/json.hpp>
#include <phosphor-logging/elog-errors.hpp>
#include <phosphor-logging/log.hpp>
#include <sdbusplus/message/types.hpp>
#include <string>
#include <sys_info_param.hpp>
#include <transporthandler.hpp>
#include <tuple>
#include <vector>
#include <xyz/openbmc_project/Common/error.hpp>
#include <xyz/openbmc_project/Control/Power/ACPIPowerState/server.hpp>
#include <xyz/openbmc_project/Software/Activation/server.hpp>
#include <xyz/openbmc_project/Software/Version/server.hpp>
#include <xyz/openbmc_project/State/BMC/server.hpp>

extern sd_bus* bus;

constexpr auto bmc_state_interface = "xyz.openbmc_project.State.BMC";
constexpr auto bmc_state_property = "CurrentBMCState";

static constexpr auto redundancyIntf =
    "xyz.openbmc_project.Software.RedundancyPriority";
static constexpr auto versionIntf = "xyz.openbmc_project.Software.Version";
static constexpr auto activationIntf =
    "xyz.openbmc_project.Software.Activation";
static constexpr auto softwareRoot = "/xyz/openbmc_project/software";

void register_netfn_app_functions() __attribute__((constructor));

using namespace phosphor::logging;
using namespace sdbusplus::xyz::openbmc_project::Common::Error;
using Version = sdbusplus::xyz::openbmc_project::Software::server::Version;
using Activation =
    sdbusplus::xyz::openbmc_project::Software::server::Activation;
using BMC = sdbusplus::xyz::openbmc_project::State::server::BMC;
namespace fs = std::filesystem;

typedef struct
{
    uint8_t busId;
    uint8_t slaveAddr;
    uint8_t slaveAddrMask;
    std::vector<uint8_t> data;
    std::vector<uint8_t> dataMask;
} i2cMasterWRWhitelist;

static std::vector<i2cMasterWRWhitelist>& getWRWhitelist()
{
    static std::vector<i2cMasterWRWhitelist> wrWhitelist;
    return wrWhitelist;
}

static constexpr const char* i2cMasterWRWhitelistFile =
    "/usr/share/ipmi-providers/master_write_read_white_list.json";

static constexpr uint8_t maxIPMIWriteReadSize = 144;
static constexpr const char* filtersStr = "filters";
static constexpr const char* busIdStr = "busId";
static constexpr const char* slaveAddrStr = "slaveAddr";
static constexpr const char* slaveAddrMaskStr = "slaveAddrMask";
static constexpr const char* cmdStr = "command";
static constexpr const char* cmdMaskStr = "commandMask";
static constexpr int base_16 = 16;

/**
 * @brief Returns the Version info from primary s/w object
 *
 * Get the Version info from the active s/w object which is having high
 * "Priority" value(a smaller number is a higher priority) and "Purpose"
 * is "BMC" from the list of all s/w objects those are implementing
 * RedundancyPriority interface from the given softwareRoot path.
 *
 * @return On success returns the Version info from primary s/w object.
 *
 */
std::string getActiveSoftwareVersionInfo(ipmi::Context::ptr ctx)
{
    std::string revision{};
    ipmi::ObjectTree objectTree;
    try
    {
        objectTree =
            ipmi::getAllDbusObjects(*ctx->bus, softwareRoot, redundancyIntf);
    }
    catch (sdbusplus::exception::SdBusError& e)
    {
        log<level::ERR>("Failed to fetch redundancy object from dbus",
                        entry("INTERFACE=%s", redundancyIntf),
                        entry("ERRMSG=%s", e.what()));
        elog<InternalFailure>();
    }

    auto objectFound = false;
    for (auto& softObject : objectTree)
    {
        auto service =
            ipmi::getService(*ctx->bus, redundancyIntf, softObject.first);
        auto objValueTree =
            ipmi::getManagedObjects(*ctx->bus, service, softwareRoot);

        auto minPriority = 0xFF;
        for (const auto& objIter : objValueTree)
        {
            try
            {
                auto& intfMap = objIter.second;
                auto& redundancyPriorityProps = intfMap.at(redundancyIntf);
                auto& versionProps = intfMap.at(versionIntf);
                auto& activationProps = intfMap.at(activationIntf);
                auto priority =
                    std::get<uint8_t>(redundancyPriorityProps.at("Priority"));
                auto purpose =
                    std::get<std::string>(versionProps.at("Purpose"));
                auto activation =
                    std::get<std::string>(activationProps.at("Activation"));
                auto version =
                    std::get<std::string>(versionProps.at("Version"));
                if ((Version::convertVersionPurposeFromString(purpose) ==
                     Version::VersionPurpose::BMC) &&
                    (Activation::convertActivationsFromString(activation) ==
                     Activation::Activations::Active))
                {
                    if (priority < minPriority)
                    {
                        minPriority = priority;
                        objectFound = true;
                        revision = std::move(version);
                    }
                }
            }
            catch (const std::exception& e)
            {
                log<level::ERR>(e.what());
            }
        }
    }

    if (!objectFound)
    {
        log<level::ERR>("Could not found an BMC software Object");
        elog<InternalFailure>();
    }

    return revision;
}

bool getCurrentBmcState()
{
    sdbusplus::bus::bus bus{ipmid_get_sd_bus_connection()};

    // Get the Inventory object implementing the BMC interface
    ipmi::DbusObjectInfo bmcObject =
        ipmi::getDbusObject(bus, bmc_state_interface);
    auto variant =
        ipmi::getDbusProperty(bus, bmcObject.second, bmcObject.first,
                              bmc_state_interface, bmc_state_property);

    return std::holds_alternative<std::string>(variant) &&
           BMC::convertBMCStateFromString(std::get<std::string>(variant)) ==
               BMC::BMCState::Ready;
}

bool getCurrentBmcStateWithFallback(const bool fallbackAvailability)
{
    try
    {
        return getCurrentBmcState();
    }
    catch (...)
    {
        // Nothing provided the BMC interface, therefore return whatever was
        // configured as the default.
        return fallbackAvailability;
    }
}

namespace acpi_state
{
using namespace sdbusplus::xyz::openbmc_project::Control::Power::server;

const static constexpr char* acpiObjPath =
    "/xyz/openbmc_project/control/host0/acpi_power_state";
const static constexpr char* acpiInterface =
    "xyz.openbmc_project.Control.Power.ACPIPowerState";
const static constexpr char* sysACPIProp = "SysACPIStatus";
const static constexpr char* devACPIProp = "DevACPIStatus";

enum class PowerStateType : uint8_t
{
    sysPowerState = 0x00,
    devPowerState = 0x01,
};

// Defined in 20.6 of ipmi doc
enum class PowerState : uint8_t
{
    s0G0D0 = 0x00,
    s1D1 = 0x01,
    s2D2 = 0x02,
    s3D3 = 0x03,
    s4 = 0x04,
    s5G2 = 0x05,
    s4S5 = 0x06,
    g3 = 0x07,
    sleep = 0x08,
    g1Sleep = 0x09,
    override = 0x0a,
    legacyOn = 0x20,
    legacyOff = 0x21,
    unknown = 0x2a,
    noChange = 0x7f,
};

static constexpr uint8_t stateChanged = 0x80;

struct ACPIState
{
    uint8_t sysACPIState;
    uint8_t devACPIState;
} __attribute__((packed));

std::map<ACPIPowerState::ACPI, PowerState> dbusToIPMI = {
    {ACPIPowerState::ACPI::S0_G0_D0, PowerState::s0G0D0},
    {ACPIPowerState::ACPI::S1_D1, PowerState::s1D1},
    {ACPIPowerState::ACPI::S2_D2, PowerState::s2D2},
    {ACPIPowerState::ACPI::S3_D3, PowerState::s3D3},
    {ACPIPowerState::ACPI::S4, PowerState::s4},
    {ACPIPowerState::ACPI::S5_G2, PowerState::s5G2},
    {ACPIPowerState::ACPI::S4_S5, PowerState::s4S5},
    {ACPIPowerState::ACPI::G3, PowerState::g3},
    {ACPIPowerState::ACPI::SLEEP, PowerState::sleep},
    {ACPIPowerState::ACPI::G1_SLEEP, PowerState::g1Sleep},
    {ACPIPowerState::ACPI::OVERRIDE, PowerState::override},
    {ACPIPowerState::ACPI::LEGACY_ON, PowerState::legacyOn},
    {ACPIPowerState::ACPI::LEGACY_OFF, PowerState::legacyOff},
    {ACPIPowerState::ACPI::Unknown, PowerState::unknown}};

bool isValidACPIState(acpi_state::PowerStateType type, uint8_t state)
{
    if (type == acpi_state::PowerStateType::sysPowerState)
    {
        if ((state <= static_cast<uint8_t>(acpi_state::PowerState::override)) ||
            (state == static_cast<uint8_t>(acpi_state::PowerState::legacyOn)) ||
            (state ==
             static_cast<uint8_t>(acpi_state::PowerState::legacyOff)) ||
            (state == static_cast<uint8_t>(acpi_state::PowerState::unknown)) ||
            (state == static_cast<uint8_t>(acpi_state::PowerState::noChange)))
        {
            return true;
        }
        else
        {
            return false;
        }
    }
    else if (type == acpi_state::PowerStateType::devPowerState)
    {
        if ((state <= static_cast<uint8_t>(acpi_state::PowerState::s3D3)) ||
            (state == static_cast<uint8_t>(acpi_state::PowerState::unknown)) ||
            (state == static_cast<uint8_t>(acpi_state::PowerState::noChange)))
        {
            return true;
        }
        else
        {
            return false;
        }
    }
    else
    {
        return false;
    }
    return false;
}
} // namespace acpi_state

ipmi_ret_t ipmi_app_set_acpi_power_state(ipmi_netfn_t netfn, ipmi_cmd_t cmd,
                                         ipmi_request_t request,
                                         ipmi_response_t response,
                                         ipmi_data_len_t data_len,
                                         ipmi_context_t context)
{
    auto s = static_cast<uint8_t>(acpi_state::PowerState::unknown);
    ipmi_ret_t rc = IPMI_CC_OK;

    sdbusplus::bus::bus bus{ipmid_get_sd_bus_connection()};

    auto value = acpi_state::ACPIPowerState::ACPI::Unknown;

    auto* req = reinterpret_cast<acpi_state::ACPIState*>(request);

    if (*data_len != sizeof(acpi_state::ACPIState))
    {
        log<level::ERR>("set_acpi invalid len");
        *data_len = 0;
        return IPMI_CC_REQ_DATA_LEN_INVALID;
    }

    *data_len = 0;

    if (req->sysACPIState & acpi_state::stateChanged)
    {
        // set system power state
        s = req->sysACPIState & ~acpi_state::stateChanged;

        if (!acpi_state::isValidACPIState(
                acpi_state::PowerStateType::sysPowerState, s))
        {
            log<level::ERR>("set_acpi_power sys invalid input",
                            entry("S=%x", s));
            return IPMI_CC_PARM_OUT_OF_RANGE;
        }

        // valid input
        if (s == static_cast<uint8_t>(acpi_state::PowerState::noChange))
        {
            log<level::DEBUG>("No change for system power state");
        }
        else
        {
            auto found = std::find_if(
                acpi_state::dbusToIPMI.begin(), acpi_state::dbusToIPMI.end(),
                [&s](const auto& iter) {
                    return (static_cast<uint8_t>(iter.second) == s);
                });

            value = found->first;

            try
            {
                auto acpiObject =
                    ipmi::getDbusObject(bus, acpi_state::acpiInterface);
                ipmi::setDbusProperty(bus, acpiObject.second, acpiObject.first,
                                      acpi_state::acpiInterface,
                                      acpi_state::sysACPIProp,
                                      convertForMessage(value));
            }
            catch (const InternalFailure& e)
            {
                log<level::ERR>("Failed in set ACPI system property",
                                entry("EXCEPTION=%s", e.what()));
                return IPMI_CC_UNSPECIFIED_ERROR;
            }
        }
    }
    else
    {
        log<level::DEBUG>("Do not change system power state");
    }

    if (req->devACPIState & acpi_state::stateChanged)
    {
        // set device power state
        s = req->devACPIState & ~acpi_state::stateChanged;
        if (!acpi_state::isValidACPIState(
                acpi_state::PowerStateType::devPowerState, s))
        {
            log<level::ERR>("set_acpi_power dev invalid input",
                            entry("S=%x", s));
            return IPMI_CC_PARM_OUT_OF_RANGE;
        }

        // valid input
        if (s == static_cast<uint8_t>(acpi_state::PowerState::noChange))
        {
            log<level::DEBUG>("No change for device power state");
        }
        else
        {
            auto found = std::find_if(
                acpi_state::dbusToIPMI.begin(), acpi_state::dbusToIPMI.end(),
                [&s](const auto& iter) {
                    return (static_cast<uint8_t>(iter.second) == s);
                });

            value = found->first;

            try
            {
                auto acpiObject =
                    ipmi::getDbusObject(bus, acpi_state::acpiInterface);
                ipmi::setDbusProperty(bus, acpiObject.second, acpiObject.first,
                                      acpi_state::acpiInterface,
                                      acpi_state::devACPIProp,
                                      convertForMessage(value));
            }
            catch (const InternalFailure& e)
            {
                log<level::ERR>("Failed in set ACPI device property",
                                entry("EXCEPTION=%s", e.what()));
                return IPMI_CC_UNSPECIFIED_ERROR;
            }
        }
    }
    else
    {
        log<level::DEBUG>("Do not change device power state");
    }

    return rc;
}

/**
 *  @brief implements the get ACPI power state command
 *
 *  @return IPMI completion code plus response data on success.
 *   -  ACPI system power state
 *   -  ACPI device power state
 **/
ipmi::RspType<uint8_t, // acpiSystemPowerState
              uint8_t  // acpiDevicePowerState
              >
    ipmiGetAcpiPowerState()
{
    uint8_t sysAcpiState;
    uint8_t devAcpiState;

    sdbusplus::bus::bus bus{ipmid_get_sd_bus_connection()};

    try
    {
        auto acpiObject = ipmi::getDbusObject(bus, acpi_state::acpiInterface);

        auto sysACPIVal = ipmi::getDbusProperty(
            bus, acpiObject.second, acpiObject.first, acpi_state::acpiInterface,
            acpi_state::sysACPIProp);
        auto sysACPI = acpi_state::ACPIPowerState::convertACPIFromString(
            std::get<std::string>(sysACPIVal));
        sysAcpiState = static_cast<uint8_t>(acpi_state::dbusToIPMI.at(sysACPI));

        auto devACPIVal = ipmi::getDbusProperty(
            bus, acpiObject.second, acpiObject.first, acpi_state::acpiInterface,
            acpi_state::devACPIProp);
        auto devACPI = acpi_state::ACPIPowerState::convertACPIFromString(
            std::get<std::string>(devACPIVal));
        devAcpiState = static_cast<uint8_t>(acpi_state::dbusToIPMI.at(devACPI));
    }
    catch (const InternalFailure& e)
    {
        return ipmi::responseUnspecifiedError();
    }

    return ipmi::responseSuccess(sysAcpiState, devAcpiState);
}

typedef struct
{
    char major;
    char minor;
    uint16_t d[2];
} Revision;

/* Currently supports the vx.x-x-[-x] and v1.x.x-x-[-x] format. It will     */
/* return -1 if not in those formats, this routine knows how to parse       */
/* version = v0.6-19-gf363f61-dirty                                         */
/*            ^ ^ ^^          ^                                             */
/*            | |  |----------|-- additional details                        */
/*            | |---------------- Minor                                     */
/*            |------------------ Major                                     */
/* and version = v1.99.10-113-g65edf7d-r3-0-g9e4f715                        */
/*                ^ ^  ^^ ^                                                 */
/*                | |  |--|---------- additional details                    */
/*                | |---------------- Minor                                 */
/*                |------------------ Major                                 */
/* Additional details : If the option group exists it will force Auxiliary  */
/* Firmware Revision Information 4th byte to 1 indicating the build was     */
/* derived with additional edits                                            */
int convertVersion(std::string s, Revision& rev)
{
    std::string token;
    uint16_t commits;

    auto location = s.find_first_of('v');
    if (location != std::string::npos)
    {
        s = s.substr(location + 1);
    }

    if (!s.empty())
    {
        location = s.find_first_of(".");
        if (location != std::string::npos)
        {
            rev.major =
                static_cast<char>(std::stoi(s.substr(0, location), 0, 16));
            token = s.substr(location + 1);
        }

        if (!token.empty())
        {
            location = token.find_first_of(".-");
            if (location != std::string::npos)
            {
                rev.minor = static_cast<char>(
                    std::stoi(token.substr(0, location), 0, 16));
                token = token.substr(location + 1);
            }
        }

        // Capture the number of commits on top of the minor tag.
        // I'm using BE format like the ipmi spec asked for
        location = token.find_first_of(".-");
        if (!token.empty())
        {
            commits = std::stoi(token.substr(0, location), 0, 16);
            rev.d[0] = (commits >> 8) | (commits << 8);

            // commit number we skip
            location = token.find_first_of(".-");
            if (location != std::string::npos)
            {
                token = token.substr(location + 1);
            }
        }
        else
        {
            rev.d[0] = 0;
        }

        if (location != std::string::npos)
        {
            token = token.substr(location + 1);
        }

        // Any value of the optional parameter forces it to 1
        location = token.find_first_of(".-");
        if (location != std::string::npos)
        {
            token = token.substr(location + 1);
        }
        commits = (!token.empty()) ? 1 : 0;

        // We do this operation to get this displayed in least significant bytes
        // of ipmitool device id command.
        rev.d[1] = (commits >> 8) | (commits << 8);
    }

    return 0;
}

/* @brief: Implement the Get Device ID IPMI command per the IPMI spec
 *  @param[in] ctx - shared_ptr to an IPMI context struct
 *
 *  @returns IPMI completion code plus response data
 *   - Device ID (manufacturer defined)
 *   - Device revision[4 bits]; reserved[3 bits]; SDR support[1 bit]
 *   - FW revision major[7 bits] (binary encoded); available[1 bit]
 *   - FW Revision minor (BCD encoded)
 *   - IPMI version (0x02 for IPMI 2.0)
 *   - device support (bitfield of supported options)
 *   - MFG IANA ID (3 bytes)
 *   - product ID (2 bytes)
 *   - AUX info (4 bytes)
 */
ipmi::RspType<uint8_t,  // Device ID
              uint8_t,  // Device Revision
              uint8_t,  // Firmware Revision Major
              uint8_t,  // Firmware Revision minor
              uint8_t,  // IPMI version
              uint8_t,  // Additional device support
              uint24_t, // MFG ID
              uint16_t, // Product ID
              uint32_t  // AUX info
              >
    ipmiAppGetDeviceId(ipmi::Context::ptr ctx)
{
    int r = -1;
    Revision rev = {0};
    static struct
    {
        uint8_t id;
        uint8_t revision;
        uint8_t fw[2];
        uint8_t ipmiVer;
        uint8_t addnDevSupport;
        uint24_t manufId;
        uint16_t prodId;
        uint32_t aux;
    } devId;
    static bool dev_id_initialized = false;
    static bool defaultActivationSetting = true;
    const char* filename = "/usr/share/ipmi-providers/dev_id.json";
    constexpr auto ipmiDevIdStateShift = 7;
    constexpr auto ipmiDevIdFw1Mask = ~(1 << ipmiDevIdStateShift);

    if (!dev_id_initialized)
    {
        try
        {
            auto version = getActiveSoftwareVersionInfo(ctx);
            r = convertVersion(version, rev);
        }
        catch (const std::exception& e)
        {
            log<level::ERR>(e.what());
        }

        if (r >= 0)
        {
            // bit7 identifies if the device is available
            // 0=normal operation
            // 1=device firmware, SDR update,
            // or self-initialization in progress.
            // The availability may change in run time, so mask here
            // and initialize later.
            devId.fw[0] = rev.major & ipmiDevIdFw1Mask;

            rev.minor = (rev.minor > 99 ? 99 : rev.minor);
            devId.fw[1] = rev.minor % 10 + (rev.minor / 10) * 16;
            std::memcpy(&devId.aux, rev.d, 4);
        }

        // IPMI Spec version 2.0
        devId.ipmiVer = 2;

        std::ifstream devIdFile(filename);
        if (devIdFile.is_open())
        {
            auto data = nlohmann::json::parse(devIdFile, nullptr, false);
            if (!data.is_discarded())
            {
                devId.id = data.value("id", 0);
                devId.revision = data.value("revision", 0);
                devId.addnDevSupport = data.value("addn_dev_support", 0);
                devId.manufId = data.value("manuf_id", 0);
                devId.prodId = data.value("prod_id", 0);
                devId.aux = data.value("aux", 0);

                // Set the availablitity of the BMC.
                defaultActivationSetting = data.value("availability", true);

                // Don't read the file every time if successful
                dev_id_initialized = true;
            }
            else
            {
                log<level::ERR>("Device ID JSON parser failure");
                return ipmi::responseUnspecifiedError();
            }
        }
        else
        {
            log<level::ERR>("Device ID file not found");
            return ipmi::responseUnspecifiedError();
        }
    }

    // Set availability to the actual current BMC state
    devId.fw[0] &= ipmiDevIdFw1Mask;
    if (!getCurrentBmcStateWithFallback(defaultActivationSetting))
    {
        devId.fw[0] |= (1 << ipmiDevIdStateShift);
    }

    return ipmi::responseSuccess(
        devId.id, devId.revision, devId.fw[0], devId.fw[1], devId.ipmiVer,
        devId.addnDevSupport, devId.manufId, devId.prodId, devId.aux);
}

auto ipmiAppGetSelfTestResults() -> ipmi::RspType<uint8_t, uint8_t>
{
    // Byte 2:
    //  55h - No error.
    //  56h - Self Test function not implemented in this controller.
    //  57h - Corrupted or inaccesssible data or devices.
    //  58h - Fatal hardware error.
    //  FFh - reserved.
    //  all other: Device-specific 'internal failure'.
    //  Byte 3:
    //      For byte 2 = 55h, 56h, FFh:     00h
    //      For byte 2 = 58h, all other:    Device-specific
    //      For byte 2 = 57h:   self-test error bitfield.
    //      Note: returning 57h does not imply that all test were run.
    //      [7] 1b = Cannot access SEL device.
    //      [6] 1b = Cannot access SDR Repository.
    //      [5] 1b = Cannot access BMC FRU device.
    //      [4] 1b = IPMB signal lines do not respond.
    //      [3] 1b = SDR Repository empty.
    //      [2] 1b = Internal Use Area of BMC FRU corrupted.
    //      [1] 1b = controller update 'boot block' firmware corrupted.
    //      [0] 1b = controller operational firmware corrupted.
    constexpr uint8_t notImplemented = 0x56;
    constexpr uint8_t zero = 0;
    return ipmi::responseSuccess(notImplemented, zero);
}

static constexpr size_t uuidBinaryLength = 16;
static std::array<uint8_t, uuidBinaryLength> rfc4122ToIpmi(std::string rfc4122)
{
    using Argument = xyz::openbmc_project::Common::InvalidArgument;
    // UUID is in RFC4122 format. Ex: 61a39523-78f2-11e5-9862-e6402cfc3223
    // Per IPMI Spec 2.0 need to convert to 16 hex bytes and reverse the byte
    // order
    // Ex: 0x2332fc2c40e66298e511f2782395a361
    constexpr size_t uuidHexLength = (2 * uuidBinaryLength);
    constexpr size_t uuidRfc4122Length = (uuidHexLength + 4);
    std::array<uint8_t, uuidBinaryLength> uuid;
    if (rfc4122.size() == uuidRfc4122Length)
    {
        rfc4122.erase(std::remove(rfc4122.begin(), rfc4122.end(), '-'),
                      rfc4122.end());
    }
    if (rfc4122.size() != uuidHexLength)
    {
        elog<InvalidArgument>(Argument::ARGUMENT_NAME("rfc4122"),
                              Argument::ARGUMENT_VALUE(rfc4122.c_str()));
    }
    for (size_t ind = 0; ind < uuidHexLength; ind += 2)
    {
        char v[3];
        v[0] = rfc4122[ind];
        v[1] = rfc4122[ind + 1];
        v[2] = 0;
        size_t err;
        long b;
        try
        {
            b = std::stoul(v, &err, 16);
        }
        catch (std::exception& e)
        {
            elog<InvalidArgument>(Argument::ARGUMENT_NAME("rfc4122"),
                                  Argument::ARGUMENT_VALUE(rfc4122.c_str()));
        }
        // check that exactly two ascii bytes were converted
        if (err != 2)
        {
            elog<InvalidArgument>(Argument::ARGUMENT_NAME("rfc4122"),
                                  Argument::ARGUMENT_VALUE(rfc4122.c_str()));
        }
        uuid[uuidBinaryLength - (ind / 2) - 1] = static_cast<uint8_t>(b);
    }
    return uuid;
}

auto ipmiAppGetDeviceGuid()
    -> ipmi::RspType<std::array<uint8_t, uuidBinaryLength>>
{
    // return a fixed GUID based on /etc/machine-id
    // This should match the /redfish/v1/Managers/bmc's UUID data

    // machine specific application ID (for BMC ID)
    // generated by systemd-id128 -p new as per man page
    static constexpr sd_id128_t bmcUuidAppId = SD_ID128_MAKE(
        e0, e1, 73, 76, 64, 61, 47, da, a5, 0c, d0, cc, 64, 12, 45, 78);

    sd_id128_t bmcUuid;
    // create the UUID from /etc/machine-id via the systemd API
    sd_id128_get_machine_app_specific(bmcUuidAppId, &bmcUuid);

    char bmcUuidCstr[SD_ID128_STRING_MAX];
    std::string systemUuid = sd_id128_to_string(bmcUuid, bmcUuidCstr);

    std::array<uint8_t, uuidBinaryLength> uuid = rfc4122ToIpmi(systemUuid);
    return ipmi::responseSuccess(uuid);
}

auto ipmiAppGetBtCapabilities()
    -> ipmi::RspType<uint8_t, uint8_t, uint8_t, uint8_t, uint8_t>
{
    // Per IPMI 2.0 spec, the input and output buffer size must be the max
    // buffer size minus one byte to allocate space for the length byte.
    constexpr uint8_t nrOutstanding = 0x01;
    constexpr uint8_t inputBufferSize = MAX_IPMI_BUFFER - 1;
    constexpr uint8_t outputBufferSize = MAX_IPMI_BUFFER - 1;
    constexpr uint8_t transactionTime = 0x0A;
    constexpr uint8_t nrRetries = 0x01;

    return ipmi::responseSuccess(nrOutstanding, inputBufferSize,
                                 outputBufferSize, transactionTime, nrRetries);
}

auto ipmiAppGetSystemGuid() -> ipmi::RspType<std::array<uint8_t, 16>>
{
    static constexpr auto bmcInterface =
        "xyz.openbmc_project.Inventory.Item.Bmc";
    static constexpr auto uuidInterface = "xyz.openbmc_project.Common.UUID";
    static constexpr auto uuidProperty = "UUID";

    ipmi::Value propValue;
    try
    {
        // Get the Inventory object implementing BMC interface
        auto busPtr = getSdBus();
        auto objectInfo = ipmi::getDbusObject(*busPtr, bmcInterface);

        // Read UUID property value from bmcObject
        // UUID is in RFC4122 format Ex: 61a39523-78f2-11e5-9862-e6402cfc3223
        propValue =
            ipmi::getDbusProperty(*busPtr, objectInfo.second, objectInfo.first,
                                  uuidInterface, uuidProperty);
    }
    catch (const InternalFailure& e)
    {
        log<level::ERR>("Failed in reading BMC UUID property",
                        entry("INTERFACE=%s", uuidInterface),
                        entry("PROPERTY=%s", uuidProperty));
        return ipmi::responseUnspecifiedError();
    }
    std::array<uint8_t, 16> uuid;
    std::string rfc4122Uuid = std::get<std::string>(propValue);
    try
    {
        // convert to IPMI format
        uuid = rfc4122ToIpmi(rfc4122Uuid);
    }
    catch (const InvalidArgument& e)
    {
        log<level::ERR>("Failed in parsing BMC UUID property",
                        entry("INTERFACE=%s", uuidInterface),
                        entry("PROPERTY=%s", uuidProperty),
                        entry("VALUE=%s", rfc4122Uuid.c_str()));
        return ipmi::responseUnspecifiedError();
    }
    return ipmi::responseSuccess(uuid);
}

static std::unique_ptr<SysInfoParamStore> sysInfoParamStore;

static std::string sysInfoReadSystemName()
{
    // Use the BMC hostname as the "System Name."
    char hostname[HOST_NAME_MAX + 1] = {};
    if (gethostname(hostname, HOST_NAME_MAX) != 0)
    {
        perror("System info parameter: system name");
    }
    return hostname;
}

struct IpmiSysInfoResp
{
    uint8_t paramRevision;
    uint8_t setSelector;
    union
    {
        struct
        {
            uint8_t encoding;
            uint8_t stringLen;
            uint8_t stringData0[14];
        } __attribute__((packed));
        uint8_t stringDataN[16];
        uint8_t byteData;
    };
} __attribute__((packed));

/**
 * Split a string into (up to) 16-byte chunks as expected in response for get
 * system info parameter.
 *
 * @param[in] fullString: Input string to be split
 * @param[in] chunkIndex: Index of the chunk to be written out
 * @param[in,out] chunk: Output data buffer; must have 14 byte capacity if
 *          chunk_index = 0 and 16-byte capacity otherwise
 * @return the number of bytes written into the output buffer, or -EINVAL for
 * invalid arguments.
 */
static int splitStringParam(const std::string& fullString, int chunkIndex,
                            uint8_t* chunk)
{
    constexpr int maxChunk = 255;
    constexpr int smallChunk = 14;
    constexpr int chunkSize = 16;
    if (chunkIndex > maxChunk || chunk == nullptr)
    {
        return -EINVAL;
    }
    try
    {
        std::string output;
        if (chunkIndex == 0)
        {
            // Output must have 14 byte capacity.
            output = fullString.substr(0, smallChunk);
        }
        else
        {
            // Output must have 16 byte capacity.
            output = fullString.substr((chunkIndex * chunkSize) - 2, chunkSize);
        }

        std::memcpy(chunk, output.c_str(), output.length());
        return output.length();
    }
    catch (const std::out_of_range& e)
    {
        // The position was beyond the end.
        return -EINVAL;
    }
}

/**
 * Packs the Get Sys Info Request Item into the response.
 *
 * @param[in] paramString - the parameter.
 * @param[in] setSelector - the selector
 * @param[in,out] resp - the System info response.
 * @return The number of bytes packed or failure from splitStringParam().
 */
static int packGetSysInfoResp(const std::string& paramString,
                              uint8_t setSelector, IpmiSysInfoResp* resp)
{
    uint8_t* dataBuffer = resp->stringDataN;
    resp->setSelector = setSelector;
    if (resp->setSelector == 0) // First chunk has only 14 bytes.
    {
        resp->encoding = 0;
        resp->stringLen = paramString.length();
        dataBuffer = resp->stringData0;
    }
    return splitStringParam(paramString, resp->setSelector, dataBuffer);
}

ipmi_ret_t ipmi_app_get_system_info(ipmi_netfn_t netfn, ipmi_cmd_t cmd,
                                    ipmi_request_t request,
                                    ipmi_response_t response,
                                    ipmi_data_len_t dataLen,
                                    ipmi_context_t context)
{
    IpmiSysInfoResp resp = {};
    size_t respLen = 0;
    uint8_t* const reqData = static_cast<uint8_t*>(request);
    std::string paramString;
    bool found;
    std::tuple<bool, std::string> ret;
    constexpr int minRequestSize = 4;
    constexpr int paramSelector = 1;
    constexpr uint8_t revisionOnly = 0x80;
    const uint8_t paramRequested = reqData[paramSelector];
    int rc;

    if (*dataLen < minRequestSize)
    {
        return IPMI_CC_REQ_DATA_LEN_INVALID;
    }

    *dataLen = 0; // default to 0.

    // Parameters revision as of IPMI spec v2.0 rev. 1.1 (Feb 11, 2014 E6)
    resp.paramRevision = 0x11;
    if (reqData[0] & revisionOnly) // Get parameter revision only
    {
        respLen = 1;
        goto writeResponse;
    }

    // The "Set In Progress" parameter can be used for rollback of parameter
    // data and is not implemented.
    if (paramRequested == 0)
    {
        resp.byteData = 0;
        respLen = 2;
        goto writeResponse;
    }

    if (sysInfoParamStore == nullptr)
    {
        sysInfoParamStore = std::make_unique<SysInfoParamStore>();
        sysInfoParamStore->update(IPMI_SYSINFO_SYSTEM_NAME,
                                  sysInfoReadSystemName);
    }

    // Parameters other than Set In Progress are assumed to be strings.
    ret = sysInfoParamStore->lookup(paramRequested);
    found = std::get<0>(ret);
    paramString = std::get<1>(ret);
    if (!found)
    {
        return IPMI_CC_SYSTEM_INFO_PARAMETER_NOT_SUPPORTED;
    }
    // TODO: Cache each parameter across multiple calls, until the whole string
    // has been read out. Otherwise, it's possible for a parameter to change
    // between requests for its chunks, returning chunks incoherent with each
    // other. For now, the parameter store is simply required to have only
    // idempotent callbacks.
    rc = packGetSysInfoResp(paramString, reqData[2], &resp);
    if (rc == -EINVAL)
    {
        return IPMI_CC_RESPONSE_ERROR;
    }

    respLen = sizeof(resp); // Write entire string data chunk in response.

writeResponse:
    std::memcpy(response, &resp, sizeof(resp));
    *dataLen = respLen;
    return IPMI_CC_OK;
}

inline std::vector<uint8_t> convertStringToData(const std::string& command)
{
    std::istringstream iss(command);
    std::string token;
    std::vector<uint8_t> dataValue;
    while (std::getline(iss, token, ' '))
    {
        dataValue.emplace_back(
            static_cast<uint8_t>(std::stoul(token, nullptr, base_16)));
    }
    return dataValue;
}

static bool populateI2CMasterWRWhitelist()
{
    nlohmann::json data = nullptr;
    std::ifstream jsonFile(i2cMasterWRWhitelistFile);

    if (!jsonFile.good())
    {
        log<level::WARNING>("i2c white list file not found!",
                            entry("FILE_NAME: %s", i2cMasterWRWhitelistFile));
        return false;
    }

    try
    {
        data = nlohmann::json::parse(jsonFile, nullptr, false);
    }
    catch (nlohmann::json::parse_error& e)
    {
        log<level::ERR>("Corrupted i2c white list config file",
                        entry("FILE_NAME: %s", i2cMasterWRWhitelistFile),
                        entry("MSG: %s", e.what()));
        return false;
    }

    try
    {
        // Example JSON Structure format
        // "filters": [
        //    {
        //      "Description": "Allow full read - ignore first byte write value
        //      for 0x40 to 0x4F",
        //      "busId": "0x01",
        //      "slaveAddr": "0x40",
        //      "slaveAddrMask": "0x0F",
        //      "command": "0x00",
        //      "commandMask": "0xFF"
        //    },
        //    {
        //      "Description": "Allow full read - first byte match 0x05 and
        //      ignore second byte",
        //      "busId": "0x01",
        //      "slaveAddr": "0x57",
        //      "slaveAddrMask": "0x00",
        //      "command": "0x05 0x00",
        //      "commandMask": "0x00 0xFF"
        //    },]

        nlohmann::json filters = data[filtersStr].get<nlohmann::json>();
        std::vector<i2cMasterWRWhitelist>& whitelist = getWRWhitelist();
        for (const auto& it : filters.items())
        {
            nlohmann::json filter = it.value();
            if (filter.is_null())
            {
                log<level::ERR>(
                    "Corrupted I2C master write read whitelist config file",
                    entry("FILE_NAME: %s", i2cMasterWRWhitelistFile));
                return false;
            }
            const std::vector<uint8_t>& writeData =
                convertStringToData(filter[cmdStr].get<std::string>());
            const std::vector<uint8_t>& writeDataMask =
                convertStringToData(filter[cmdMaskStr].get<std::string>());
            if (writeDataMask.size() != writeData.size())
            {
                log<level::ERR>("I2C master write read whitelist filter "
                                "mismatch for command & mask size");
                return false;
            }
            whitelist.push_back(
                {static_cast<uint8_t>(std::stoul(
                     filter[busIdStr].get<std::string>(), nullptr, base_16)),
                 static_cast<uint8_t>(
                     std::stoul(filter[slaveAddrStr].get<std::string>(),
                                nullptr, base_16)),
                 static_cast<uint8_t>(
                     std::stoul(filter[slaveAddrMaskStr].get<std::string>(),
                                nullptr, base_16)),
                 writeData, writeDataMask});
        }
        if (whitelist.size() != filters.size())
        {
            log<level::ERR>(
                "I2C master write read whitelist filter size mismatch");
            return false;
        }
    }
    catch (std::exception& e)
    {
        log<level::ERR>("I2C master write read whitelist unexpected exception",
                        entry("ERROR=%s", e.what()));
        return false;
    }
    return true;
}

static inline bool isWriteDataWhitelisted(const std::vector<uint8_t>& data,
                                          const std::vector<uint8_t>& dataMask,
                                          const std::vector<uint8_t>& writeData)
{
    std::vector<uint8_t> processedDataBuf(data.size());
    std::vector<uint8_t> processedReqBuf(dataMask.size());
    std::transform(writeData.begin(), writeData.end(), dataMask.begin(),
                   processedReqBuf.begin(), std::bit_or<uint8_t>());
    std::transform(data.begin(), data.end(), dataMask.begin(),
                   processedDataBuf.begin(), std::bit_or<uint8_t>());

    return (processedDataBuf == processedReqBuf);
}

static bool isCmdWhitelisted(uint8_t busId, uint8_t slaveAddr,
                             std::vector<uint8_t>& writeData)
{
    std::vector<i2cMasterWRWhitelist>& whiteList = getWRWhitelist();
    for (const auto& wlEntry : whiteList)
    {
        if ((busId == wlEntry.busId) &&
            ((slaveAddr | wlEntry.slaveAddrMask) ==
             (wlEntry.slaveAddr | wlEntry.slaveAddrMask)))
        {
            const std::vector<uint8_t>& dataMask = wlEntry.dataMask;
            // Skip as no-match, if requested write data is more than the
            // write data mask size
            if (writeData.size() > dataMask.size())
            {
                continue;
            }
            if (isWriteDataWhitelisted(wlEntry.data, dataMask, writeData))
            {
                return true;
            }
        }
    }
    return false;
}

/** @brief implements master write read IPMI command which can be used for
 * low-level I2C/SMBus write, read or write-read access
 *  @param isPrivateBus -to indicate private bus usage
 *  @param busId - bus id
 *  @param channelNum - channel number
 *  @param reserved - skip 1 bit
 *  @param slaveAddr - slave address
 *  @param read count - number of bytes to be read
 *  @param writeData - data to be written
 *
 *  @returns IPMI completion code plus response data
 *   - readData - i2c response data
 */
ipmi::RspType<std::vector<uint8_t>>
    ipmiMasterWriteRead(bool isPrivateBus, uint3_t busId, uint4_t channelNum,
                        bool reserved, uint7_t slaveAddr, uint8_t readCount,
                        std::vector<uint8_t> writeData)
{
    i2c_rdwr_ioctl_data msgReadWrite = {0};
    i2c_msg i2cmsg[2] = {0};

    if (readCount > maxIPMIWriteReadSize)
    {
        log<level::ERR>("Master write read command: Read count exceeds limit");
        return ipmi::responseParmOutOfRange();
    }
    const size_t writeCount = writeData.size();
    if (!readCount && !writeCount)
    {
        log<level::ERR>("Master write read command: Read & write count are 0");
        return ipmi::responseInvalidFieldRequest();
    }
    if (!isCmdWhitelisted(static_cast<uint8_t>(busId),
                          static_cast<uint8_t>(slaveAddr), writeData))
    {
        log<level::ERR>("Master write read request blocked!",
                        entry("BUS=%d", static_cast<uint8_t>(busId)),
                        entry("ADDR=0x%x", static_cast<uint8_t>(slaveAddr)));
        return ipmi::responseInvalidFieldRequest();
    }
    std::vector<uint8_t> readBuf(readCount);
    std::string i2cBus =
        "/dev/i2c-" + std::to_string(static_cast<uint8_t>(busId));

    int i2cDev = ::open(i2cBus.c_str(), O_RDWR | O_CLOEXEC);
    if (i2cDev < 0)
    {
        log<level::ERR>("Failed to open i2c bus",
                        entry("BUS=%s", i2cBus.c_str()));
        return ipmi::responseInvalidFieldRequest();
    }

    int msgCount = 0;
    if (writeCount)
    {
        i2cmsg[msgCount].addr = static_cast<uint8_t>(slaveAddr);
        i2cmsg[msgCount].flags = 0x00;
        i2cmsg[msgCount].len = writeCount;
        i2cmsg[msgCount].buf = writeData.data();
        msgCount++;
    }
    if (readCount)
    {
        i2cmsg[msgCount].addr = static_cast<uint8_t>(slaveAddr);
        i2cmsg[msgCount].flags = I2C_M_RD;
        i2cmsg[msgCount].len = readCount;
        i2cmsg[msgCount].buf = readBuf.data();
        msgCount++;
    }

    msgReadWrite.msgs = i2cmsg;
    msgReadWrite.nmsgs = msgCount;

    int ret = ::ioctl(i2cDev, I2C_RDWR, &msgReadWrite);
    ::close(i2cDev);

    if (ret < 0)
    {
        log<level::ERR>("Master write read: Failed", entry("RET=%d", ret));
        return ipmi::responseUnspecifiedError();
    }
    if (readCount)
    {
        readBuf.resize(msgReadWrite.msgs[msgCount - 1].len);
    }
    return ipmi::responseSuccess(readBuf);
}

void register_netfn_app_functions()
{
    // <Get Device ID>
    ipmi::registerHandler(ipmi::prioOpenBmcBase, ipmi::netFnApp,
                          ipmi::app::cmdGetDeviceId, ipmi::Privilege::User,
                          ipmiAppGetDeviceId);

    // <Get BT Interface Capabilities>
    ipmi::registerHandler(ipmi::prioOpenBmcBase, ipmi::netFnApp,
                          ipmi::app::cmdGetBtIfaceCapabilities,
                          ipmi::Privilege::User, ipmiAppGetBtCapabilities);

    // <Reset Watchdog Timer>
    ipmi::registerHandler(ipmi::prioOpenBmcBase, ipmi::netFnApp,
                          ipmi::app::cmdResetWatchdogTimer,
                          ipmi::Privilege::Operator, ipmiAppResetWatchdogTimer);

    // <Set Watchdog Timer>
    ipmi_register_callback(NETFUN_APP, IPMI_CMD_SET_WD, NULL,
                           ipmi_app_watchdog_set, PRIVILEGE_OPERATOR);

    // <Get Watchdog Timer>
    ipmi_register_callback(NETFUN_APP, IPMI_CMD_GET_WD, NULL,
                           ipmi_app_watchdog_get, PRIVILEGE_OPERATOR);

    // <Get Self Test Results>
    ipmi::registerHandler(ipmi::prioOpenBmcBase, ipmi::netFnApp,
                          ipmi::app::cmdGetSelfTestResults,
                          ipmi::Privilege::User, ipmiAppGetSelfTestResults);

    // <Get Device GUID>
    ipmi::registerHandler(ipmi::prioOpenBmcBase, ipmi::netFnApp,
                          ipmi::app::cmdGetDeviceGuid, ipmi::Privilege::User,
                          ipmiAppGetDeviceGuid);

    // <Set ACPI Power State>
    ipmi_register_callback(NETFUN_APP, IPMI_CMD_SET_ACPI, NULL,
                           ipmi_app_set_acpi_power_state, PRIVILEGE_ADMIN);

    // <Get ACPI Power State>
    ipmi::registerHandler(ipmi::prioOpenBmcBase, ipmi::netFnApp,
                          ipmi::app::cmdGetAcpiPowerState,
                          ipmi::Privilege::Admin, ipmiGetAcpiPowerState);

    // Note: For security reason, this command will be registered only when
    // there are proper I2C Master write read whitelist
    if (populateI2CMasterWRWhitelist())
    {
        // Note: For security reasons, registering master write read as admin
        // privilege command, even though IPMI 2.0 specification allows it as
        // operator privilege.
        ipmi::registerHandler(ipmi::prioOpenBmcBase, ipmi::netFnApp,
                              ipmi::app::cmdMasterWriteRead,
                              ipmi::Privilege::Admin, ipmiMasterWriteRead);
    }

    // <Get System GUID Command>
    ipmi::registerHandler(ipmi::prioOpenBmcBase, ipmi::netFnApp,
                          ipmi::app::cmdGetSystemGuid, ipmi::Privilege::User,
                          ipmiAppGetSystemGuid);

    // <Get Channel Cipher Suites Command>
    ipmi_register_callback(NETFUN_APP, IPMI_CMD_GET_CHAN_CIPHER_SUITES, NULL,
                           getChannelCipherSuites, PRIVILEGE_CALLBACK);

    // <Get System Info Command>
    ipmi_register_callback(NETFUN_APP, IPMI_CMD_GET_SYSTEM_INFO, NULL,
                           ipmi_app_get_system_info, PRIVILEGE_USER);
    return;
}