#include "bmc_state_manager.hpp"

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

#include <gpiod.h>
#include <sys/sysinfo.h>

#include <phosphor-logging/elog-errors.hpp>
#include <phosphor-logging/lg2.hpp>
#include <sdbusplus/exception.hpp>

#include <cassert>
#include <filesystem>
#include <fstream>
#include <iostream>

namespace phosphor
{
namespace state
{
namespace manager
{

PHOSPHOR_LOG2_USING;

// When you see server:: you know we're referencing our base class
namespace server = sdbusplus::xyz::openbmc_project::State::server;

using namespace phosphor::logging;
using sdbusplus::xyz::openbmc_project::Common::Error::InternalFailure;

constexpr auto obmcQuiesceTarget = "obmc-bmc-service-quiesce@0.target";
constexpr auto obmcStandbyTarget = "multi-user.target";
constexpr auto signalDone = "done";
constexpr auto activeState = "active";

/* Map a transition to it's systemd target */
const std::map<server::BMC::Transition, const char*> SYSTEMD_TABLE = {
    {server::BMC::Transition::Reboot, "reboot.target"}};

constexpr auto SYSTEMD_SERVICE = "org.freedesktop.systemd1";
constexpr auto SYSTEMD_OBJ_PATH = "/org/freedesktop/systemd1";
constexpr auto SYSTEMD_INTERFACE = "org.freedesktop.systemd1.Manager";
constexpr auto SYSTEMD_PRP_INTERFACE = "org.freedesktop.DBus.Properties";

std::string BMC::getUnitState(const std::string& unitToCheck)
{
    std::variant<std::string> currentState;
    sdbusplus::message::object_path unitTargetPath;

    auto method = this->bus.new_method_call(SYSTEMD_SERVICE, SYSTEMD_OBJ_PATH,
                                            SYSTEMD_INTERFACE, "GetUnit");

    method.append(unitToCheck);

    try
    {
        auto result = this->bus.call(method);
        result.read(unitTargetPath);
    }
    catch (const sdbusplus::exception::exception& e)
    {
        // Not all input units will have been loaded yet so just return an
        // empty string if an exception is caught in this path
        info("Unit {UNIT} not found: {ERROR}", "UNIT", unitToCheck, "ERROR", e);
        return std::string{};
    }

    method = this->bus.new_method_call(
        SYSTEMD_SERVICE,
        static_cast<const std::string&>(unitTargetPath).c_str(),
        SYSTEMD_PRP_INTERFACE, "Get");

    method.append("org.freedesktop.systemd1.Unit", "ActiveState");

    try
    {
        auto result = this->bus.call(method);

        // Is input target active or inactive?
        result.read(currentState);
    }
    catch (const sdbusplus::exception::exception& e)
    {
        info("Error in ActiveState Get: {ERROR}", "ERROR", e);
        return std::string{};
    }
    return (std::get<std::string>(currentState));
}

void BMC::discoverInitialState()
{
    // First look to see if the BMC quiesce target is active
    auto currentStateStr = getUnitState(obmcQuiesceTarget);
    if (currentStateStr == activeState)
    {
        info("Setting the BMCState field to BMC_QUIESCED");
        this->currentBMCState(BMCState::Quiesced);
        return;
    }

    // If not quiesced, then check standby target
    currentStateStr = getUnitState(obmcStandbyTarget);
    if (currentStateStr == activeState)
    {
        info("Setting the BMCState field to BMC_READY");
        this->currentBMCState(BMCState::Ready);
    }
    else
    {
        info("Setting the BMCState field to BMC_NOTREADY");
        this->currentBMCState(BMCState::NotReady);
    }

    return;
}

void BMC::subscribeToSystemdSignals()
{
    auto method = this->bus.new_method_call(SYSTEMD_SERVICE, SYSTEMD_OBJ_PATH,
                                            SYSTEMD_INTERFACE, "Subscribe");

    try
    {
        this->bus.call(method);
    }
    catch (const sdbusplus::exception::exception& e)
    {
        error("Failed to subscribe to systemd signals: {ERROR}", "ERROR", e);
        elog<InternalFailure>();
    }

    return;
}

void BMC::executeTransition(const Transition tranReq)
{
    // HardReboot does not shutdown any services and immediately transitions
    // into the reboot process
    if (server::BMC::Transition::HardReboot == tranReq)
    {
        // Put BMC state not NotReady when issuing a BMC reboot
        // and stop monitoring for state changes
        this->currentBMCState(BMCState::NotReady);
        this->stateSignal.reset();

        auto method = this->bus.new_method_call(
            SYSTEMD_SERVICE, SYSTEMD_OBJ_PATH, SYSTEMD_INTERFACE, "Reboot");
        try
        {
            this->bus.call(method);
        }
        catch (const sdbusplus::exception::exception& e)
        {
            info("Error in HardReboot: {ERROR}", "ERROR", e);
        }
    }
    else
    {
        // Check to make sure it can be found
        auto iter = SYSTEMD_TABLE.find(tranReq);
        if (iter == SYSTEMD_TABLE.end())
            return;

        const auto& sysdUnit = iter->second;

        auto method = this->bus.new_method_call(
            SYSTEMD_SERVICE, SYSTEMD_OBJ_PATH, SYSTEMD_INTERFACE, "StartUnit");
        // The only valid transition is reboot and that
        // needs to be irreversible once started

        method.append(sysdUnit, "replace-irreversibly");

        // Put BMC state not NotReady when issuing a BMC reboot
        // and stop monitoring for state changes
        this->currentBMCState(BMCState::NotReady);
        this->stateSignal.reset();

        try
        {
            this->bus.call(method);
        }
        catch (const sdbusplus::exception::exception& e)
        {
            info("Error in StartUnit - replace-irreversibly: {ERROR}", "ERROR",
                 e);
        }
    }
    return;
}

int BMC::bmcStateChange(sdbusplus::message::message& msg)
{
    uint32_t newStateID{};
    sdbusplus::message::object_path newStateObjPath;
    std::string newStateUnit{};
    std::string newStateResult{};

    // Read the msg and populate each variable
    msg.read(newStateID, newStateObjPath, newStateUnit, newStateResult);

    if ((newStateUnit == obmcQuiesceTarget) && (newStateResult == signalDone))
    {
        error("BMC has entered BMC_QUIESCED state");
        this->currentBMCState(BMCState::Quiesced);

        // There is no getting out of Quiesced once entered (other then BMC
        // reboot) so stop watching for signals
        auto method =
            this->bus.new_method_call(SYSTEMD_SERVICE, SYSTEMD_OBJ_PATH,
                                      SYSTEMD_INTERFACE, "Unsubscribe");

        try
        {
            this->bus.call(method);
        }
        catch (const sdbusplus::exception::exception& e)
        {
            info("Error in Unsubscribe: {ERROR}", "ERROR", e);
        }

        // disable the system state change object as well
        this->stateSignal.reset();

        return 0;
    }

    // Caught the signal that indicates the BMC is now BMC_READY
    if ((newStateUnit == obmcStandbyTarget) && (newStateResult == signalDone))
    {
        info("BMC_READY");
        this->currentBMCState(BMCState::Ready);
    }

    return 0;
}

BMC::Transition BMC::requestedBMCTransition(Transition value)
{
    info("Setting the RequestedBMCTransition field to "
         "{REQUESTED_BMC_TRANSITION}",
         "REQUESTED_BMC_TRANSITION", value);

    executeTransition(value);
    return server::BMC::requestedBMCTransition(value);
}

BMC::BMCState BMC::currentBMCState(BMCState value)
{
    info("Setting the BMCState field to {CURRENT_BMC_STATE}",
         "CURRENT_BMC_STATE", value);

    return server::BMC::currentBMCState(value);
}

BMC::RebootCause BMC::lastRebootCause(RebootCause value)
{
    info("Setting the RebootCause field to {LAST_REBOOT_CAUSE}",
         "LAST_REBOOT_CAUSE", value);

    return server::BMC::lastRebootCause(value);
}

uint64_t BMC::lastRebootTime() const
{
    using namespace std::chrono;
    struct sysinfo info;

    auto rc = sysinfo(&info);
    assert(rc == 0);

    // Since uptime is in seconds, also get the current time in seconds.
    auto now = time_point_cast<seconds>(system_clock::now());
    auto rebootTime = now - seconds(info.uptime);

    return duration_cast<milliseconds>(rebootTime.time_since_epoch()).count();
}

void BMC::discoverLastRebootCause()
{
    uint64_t bootReason = 0;
    std::ifstream file;
    auto bootstatusPath = "/sys/class/watchdog/watchdog0/bootstatus";

    file.exceptions(std::ifstream::failbit | std::ifstream::badbit |
                    std::ifstream::eofbit);

    try
    {
        file.open(bootstatusPath);
        file >> bootReason;
    }
    catch (const std::exception& e)
    {
        auto rc = errno;
        error("Failed to read sysfs file {FILE} with errno {ERRNO}", "FILE",
              bootstatusPath, "ERRNO", rc);
    }

    switch (bootReason)
    {
        case WDIOF_EXTERN1:
            this->lastRebootCause(RebootCause::Watchdog);
            return;
        case WDIOF_CARDRESET:
            this->lastRebootCause(RebootCause::POR);
            return;
        default:
            this->lastRebootCause(RebootCause::Unknown);
            // Continue below to see if more details can be found
            // on reason for reboot
            break;
    }

    // If the above code could not detect a reason, look for a the
    // reset-cause-pinhole gpio to see if it is the reason for the reboot
    auto gpioval =
        phosphor::state::manager::utils::getGpioValue("reset-cause-pinhole");

    // A 0 indicates a pinhole reset occurred
    if (0 == gpioval)
    {
        info("The BMC reset was caused by a pinhole reset");
        this->lastRebootCause(RebootCause::PinholeReset);

        // Generate log telling user a pinhole reset has occurred
        const std::string errorMsg = "xyz.openbmc_project.State.PinholeReset";
        phosphor::state::manager::utils::createError(
            this->bus, errorMsg,
            sdbusplus::xyz::openbmc_project::Logging::server::Entry::Level::
                Notice);
    }

    return;
}

} // namespace manager
} // namespace state
} // namespace phosphor