#include <cstdlib>
#include <fstream>
#include <iostream>
#include <memory>
#include <mapper.h>
#include <cassert>
#include <cctype>
#include <algorithm>
#include <phosphor-logging/log.hpp>
#include <phosphor-logging/elog-errors.hpp>
#include <xyz/openbmc_project/Common/error.hpp>
#include "time-manager.hpp"

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

std::map<std::string, TimeConfig::FUNCTOR> TimeConfig::iv_TimeParams = {
    // TODO via openbmc/openbmc#668 - openbmc/openbmc#1770 is still work in
    // progress at the time of writing this, so the use_dhcp_ntp is still using
    // the old org.openbmc settings interfaces. The whole of time manager is
    // anyway being rewritten to use new xyz.openbmc_project interfaces; as part
    // of that switching to new setting interfaces is also covered.
    {   "use_dhcp_ntp", std::make_tuple(&TimeConfig::getSystemSettings,
        &TimeConfig::updateNetworkSettings)
    }
};

namespace internal
{
namespace setting
{

/** @brief Convert d-bus enum string to native string. For eg, convert
 *         "xyz.openbmc_project.Time.Owner.Split" to "SPLIT".
 *
 *  @param[in] value - setting enum string
 *
 *  @return converted string
 */
inline auto dbusToNative(std::string&& value)
{
    auto setting = std::move(value);
    auto index = setting.find_last_of('.') + 1;
    setting = setting.substr(index, setting.length() - index);
    std::transform(setting.begin(), setting.end(), setting.begin(),
                   [](unsigned char c){ return std::toupper(c); });
    return setting;
}

} // namespace setting
} // namespace internal

TimeConfig::TimeConfig() :
    iv_dbus(nullptr),
    iv_CurrTimeMode(timeModes::MANUAL),
    iv_RequestedTimeMode(timeModes::MANUAL),
    iv_CurrTimeOwner(timeOwners::BOTH),
    iv_RequestedTimeOwner(timeOwners::BOTH),
    iv_CurrDhcpNtp("yes"),
    iv_SettingChangeAllowed(false),
    iv_SplitModeChanged(false)
{
    // Not really having anything to do here.
}

// Given a mode string, returns it's equivalent mode enum
TimeConfig::timeModes TimeConfig::getTimeMode(const char* timeMode)
{
    // We are forcing the values to be in specific case and range
    if (!strcmp(timeMode,"NTP"))
    {
        return timeModes::NTP;
    }
    else
    {
        return timeModes::MANUAL;
    }
}

// Accepts a timeMode enum and returns it's string value
const char* TimeConfig::modeStr(TimeConfig::timeModes timeMode)
{
    switch(timeMode)
    {
        case timeModes::NTP:
        {
            return "NTP";
        }
        case timeModes::MANUAL:
        {
            return "MANUAL";
        }
    }

    assert(false);
    return nullptr;
}

// Given a owner string, returns it's equivalent owner enum
TimeConfig::timeOwners TimeConfig::getTimeOwner(const char* timeOwner)
{
    if (!strcmp(timeOwner,"BMC"))
    {
        return timeOwners::BMC;
    }
    else if (!strcmp(timeOwner,"HOST"))
    {
        return timeOwners::HOST;
    }
    else if (!strcmp(timeOwner,"SPLIT"))
    {
        return timeOwners::SPLIT;
    }
    else
    {
        return timeOwners::BOTH;
    }
}

// Accepts a timeOwner enum and returns it's string value
const char* TimeConfig::ownerStr(timeOwners timeOwner)
{
    switch(timeOwner)
    {
        case timeOwners::BMC:
        {
            return "BMC";
        }
        case timeOwners::HOST:
        {
            return "HOST";
        }
        case timeOwners::SPLIT:
        {
            return "SPLIT";
        }
        case timeOwners::BOTH:
        {
            return "BOTH";
        }
    }

    assert(false);
    return nullptr;
}

// Returns the busname that hosts objPath
std::unique_ptr<char> TimeConfig::getProvider(const char* objPath)
{
    char *provider = nullptr;
    mapper_get_service(iv_dbus, objPath, &provider);
    return std::unique_ptr<char>(provider);
}

// Accepts a settings name and returns its value.
// for the variant of type 'string' now.
std::string TimeConfig::getSystemSettings(const char* key)
{
    constexpr auto settingsObj = "/org/openbmc/settings/host0";
    constexpr auto propertyIntf = "org.freedesktop.DBus.Properties";
    constexpr auto hostIntf = "org.openbmc.settings.Host";

    const char* value = nullptr;
    std::string settingsVal {};
    sd_bus_message* reply = nullptr;

    std::cout <<"Getting System Settings: " << key << std::endl;

    // Get the provider from object mapper
    auto settingsProvider = getProvider(settingsObj);
    if (!settingsProvider)
    {
        std::cerr << "Error Getting service for Settings" << std::endl;
        return value;
    }

    auto r = sd_bus_call_method(iv_dbus,
                                settingsProvider.get(),
                                settingsObj,
                                propertyIntf,
                                "Get",
                                nullptr,
                                &reply,
                                "ss",
                                hostIntf,
                                key);
    if (r < 0)
    {
        std::cerr <<"Error" << strerror(-r)
                  <<" reading system settings" << std::endl;
        goto finish;
    }

    r = sd_bus_message_read(reply, "v", "s", &value);
    if (r < 0)
    {
        std::cerr <<"Error " << strerror(-r)
                  <<" parsing settings data" << std::endl;
    }
finish:
    if (value)
    {
        settingsVal.assign(value);
    }
    reply = sd_bus_message_unref(reply);
    return settingsVal;
}

// Reads value from /org/openbmc/control/power0
// This signature on purpose to plug into time parameter map
std::string TimeConfig::getPowerSetting(const char* key)
{
    constexpr auto powerObj = "/org/openbmc/control/power0";
    constexpr auto powerIntf = "org.openbmc.control.Power";
    constexpr auto propertyIntf = "org.freedesktop.DBus.Properties";

    int value = -1;
    std::string powerValue {};
    sd_bus_message* reply = nullptr;

    std::cout <<"Reading Power Control key: " << key << std::endl;

    // Get the provider from object mapper
    auto powerProvider = getProvider(powerObj);
    if (!powerProvider)
    {
        std::cerr <<" Error getting provider for Power Settings" << std::endl;
        return powerValue;
    }

    auto r = sd_bus_call_method(iv_dbus,
                                powerProvider.get(),
                                powerObj,
                                propertyIntf,
                                "Get",
                                nullptr,
                                &reply,
                                "ss",
                                powerIntf,
                                key);
    if (r < 0)
    {
        std::cerr <<"Error " << strerror(-r)
                  << "reading: " << key << std::endl;
        goto finish;
    }

    r = sd_bus_message_read(reply, "v", "i", &value);
    if (r < 0)
    {
        std::cerr <<"Error " << strerror(-r)
                  <<" parsing " << key << "value" << std::endl;
        // For maintenance
        goto finish;
    }
finish:
    if (value != -1)
    {
        powerValue = std::to_string(value);
    }
    reply = sd_bus_message_unref(reply);
    return powerValue;
}

// Updates .network file with UseNtp=
int TimeConfig::updateNetworkSettings(const std::string& useDhcpNtp)
{
    constexpr auto networkObj = "/org/openbmc/NetworkManager/Interface";
    constexpr auto networkIntf = "org.openbmc.NetworkManager";

    std::cout << "use_dhcp_ntp = " << useDhcpNtp.c_str() << std::endl;

    // If what we have already is what it is, then just return.
    if (iv_CurrDhcpNtp == useDhcpNtp)
    {
        return 0;
    }

    // Get the provider from object mapper
    auto networkProvider = getProvider(networkObj);
    if (!networkProvider)
    {
        return -1;
    }

    auto r = sd_bus_call_method(iv_dbus,
                                networkProvider.get(),
                                networkObj,
                                networkIntf,
                                "UpdateUseNtpField",
                                nullptr,
                                nullptr,
                                "s",
                                useDhcpNtp.c_str());
    if (r < 0)
    {
        std::cerr <<"Error " << strerror(-r)
                  << " updating UseNtp" << std::endl;
    }
    else
    {
        std::cout <<"Successfully updated UseNtp=["
                  << useDhcpNtp << "]" << std::endl;

        r = writeData(cv_DhcpNtpFile, useDhcpNtp);
    }

    return 0;
}

// Reads the values from 'settingsd' and applies:
// 1) Time Mode
// 2) time Owner
// 3) UseNTP setting
// 4) Pgood
int TimeConfig::processInitialSettings(sd_bus* dbus)
{
    // First call from TimeManager to config manager
    iv_dbus = dbus;

    auto timeOwnerFunctor = std::make_tuple(&TimeConfig::getTimeOwnerSetting,
                                            &TimeConfig::updateTimeOwner);
    iv_TimeParams.emplace(settings.timeOwner, std::move(timeOwnerFunctor));
    auto timeSyncFunctor = std::make_tuple(
                               &TimeConfig::getTimeSyncMethodSetting,
                               &TimeConfig::updateTimeMode);
    iv_TimeParams.emplace(settings.timeSyncMethod, std::move(timeSyncFunctor));

    using namespace sdbusplus::bus::match::rules;
    sdbusplus::bus::bus bus(iv_dbus);

    settingsMatches.emplace_back(
        bus,
        propertiesChanged(settings.timeOwner, settings::timeOwnerIntf),
        std::bind(std::mem_fn(&TimeConfig::settingsChanged),
          this, std::placeholders::_1));

    settingsMatches.emplace_back(
        bus,
        propertiesChanged(settings.timeSyncMethod, settings::timeSyncIntf),
        std::bind(std::mem_fn(&TimeConfig::settingsChanged),
          this, std::placeholders::_1));

    // Read saved info like Who was the owner , what was the mode,
    // what was the use_dhcp_ntp setting before etc..
    auto r = readPersistentData();
    if (r < 0)
    {
        std::cerr << "Error reading the data saved in flash."
                  << std::endl;
        return r;
    }

    // Now read whats in settings and apply if allowed.
    for (auto& iter : iv_TimeParams)
    {
        // Get the settings value for various keys.
        auto reader = std::get<READER>(iter.second);
        auto value = (this->*reader)(iter.first.c_str());
        if (!value.empty())
        {
            // Get the value for the key and validate.
            auto updater = std::get<UPDATER>(iter.second);
            auto r = (this->*updater)(value);
            if (r < 0)
            {
                std::cerr << "Error setting up initial keys" << std::endl;
                return r;
            }
        }
        else
        {
            std::cerr << "key " << iter.first
                      <<" has no value: " << std::endl;
            return -1;
        }
    }

    // Now that we have taken care of consuming, push this as well
    // so that we can use the same map for handling pgood change too.
    auto readerUpdater = std::make_tuple(&TimeConfig::getPowerSetting,
                                         &TimeConfig::processPgoodChange);
    iv_TimeParams.emplace("pgood", readerUpdater);

    return 0;
}

// This is called by Property Change handler on the event of
// receiving notification on property value change.
int TimeConfig::updatePropertyVal(const char* key, const std::string& value)
{
    auto iter = iv_TimeParams.find(key);
    if (iter != iv_TimeParams.end())
    {
        auto updater = std::get<UPDATER>(iter->second);
        return (this->*updater)(value);
    }
    // Coming here indicates that we never had a matching key.
    return -1;
}

// Called by sd_event when Properties are changed in Control/power0
// Interested in change to 'pgood'
int TimeConfig::processPgoodChange(const std::string& newPgood)
{
    // Indicating that we are safe to apply any changes
    if (!newPgood.compare("0"))
    {
        iv_SettingChangeAllowed = true;
        std::cout <<"Changing time settings allowed now" << std::endl;
    }
    else
    {
        iv_SettingChangeAllowed = false;
        std::cout <<"Changing time settings is *deferred* now" << std::endl;
    }

    // if we have had users that changed the time settings
    // when we were not ready yet, do it now.
    if (iv_RequestedTimeOwner != iv_CurrTimeOwner)
    {
        auto r = updateTimeOwner(ownerStr(iv_RequestedTimeOwner));
        if (r < 0)
        {
            std::cerr << "Error updating new time owner" << std::endl;
            return r;
        }
        std::cout << "New Owner is : "
                  << ownerStr(iv_RequestedTimeOwner) << std::endl;
    }

    if (iv_RequestedTimeMode != iv_CurrTimeMode)
    {
        auto r = updateTimeMode(modeStr(iv_RequestedTimeMode));
        if (r < 0)
        {
            std::cerr << "Error updating new time mode" << std::endl;
            return r;
        }
        std::cout <<"New Mode is : "
                  << modeStr(iv_RequestedTimeMode) << std::endl;
    }
    return 0;
}

// Manipulates time owner if the system setting allows it
int TimeConfig::updateTimeMode(const std::string& newModeStr)
{
    auto r = 0;
    iv_RequestedTimeMode = getTimeMode(newModeStr.c_str());

    std::cout <<"Requested_Mode: " << newModeStr
              << " Current_Mode: " << modeStr(iv_CurrTimeMode)
              << std::endl;

    if (iv_RequestedTimeMode == iv_CurrTimeMode)
    {
        std::cout << "Mode is already set to : "
                  << newModeStr << std::endl;
        return 0;
    }

    // Also, if the time owner is HOST, then we should not allow NTP.
    // However, it may so happen that there are 2 pending requests, one for
    // changing to NTP and other for changing owner to something not HOST.
    // So check if there is a pending timeOwner change and if so, allow NTP
    // if the current is HOST and requested is non HOST.
    if (iv_CurrTimeOwner == timeOwners::HOST &&
            iv_RequestedTimeOwner == timeOwners::HOST &&
            iv_RequestedTimeMode == timeModes::NTP)
    {
        std::cout <<"Can not set mode to NTP with HOST as owner"
                  << std::endl;
        return 0;
    }

    if (iv_SettingChangeAllowed)
    {
        r = modifyNtpSettings(iv_RequestedTimeMode);
        if (r < 0)
        {
            std::cerr << "Error changing TimeMode settings"
                      << std::endl;
        }
        else
        {
            iv_CurrTimeMode = iv_RequestedTimeMode;
        }
        std::cout << "Current_Mode changed to: "
                  << newModeStr << " :: " << modeStr(iv_CurrTimeMode) << std::endl;

        // Need this when we either restart or come back from reset
        r = writeData(cv_TimeModeFile, modeStr(iv_CurrTimeMode));
    }
    else
    {
        std::cout <<"Deferring update until system state allows it"
                  << std::endl;
    }
    return r;
}

// Manipulates time owner if the system setting allows it
int TimeConfig::updateTimeOwner(const std::string& newOwnerStr)
{
    int r = 0;
    iv_RequestedTimeOwner = getTimeOwner(newOwnerStr.c_str());

    // Needed when owner changes to HOST
    std::string manualMode = "Manual";

    // Needed by time manager to do some house keeping
    iv_SplitModeChanged = false;

    if (iv_RequestedTimeOwner == iv_CurrTimeOwner)
    {
        std::cout <<"Owner is already set to : "
                  << newOwnerStr << std::endl;
        return 0;
    }

    std::cout <<"Requested_Owner: " << newOwnerStr
              << " Current_Owner: " << ownerStr(iv_CurrTimeOwner)
              << std::endl;

    if (iv_SettingChangeAllowed)
    {
        // If we are transitioning from SPLIT to something else,
        // reset the host offset.
        if (iv_CurrTimeOwner == timeOwners::SPLIT &&
                iv_RequestedTimeOwner != timeOwners::SPLIT)
        {
            // Needed by time manager to do some house keeping
            iv_SplitModeChanged = true;
        }
        iv_CurrTimeOwner = iv_RequestedTimeOwner;
        std::cout << "Current_Owner is now: "
                  << newOwnerStr << std::endl;

        // HOST and NTP are exclusive
        if (iv_CurrTimeOwner == timeOwners::HOST)
        {
            std::cout <<"Forcing the mode to MANUAL" << std::endl;
            r = updateTimeMode(manualMode);
            if (r < 0)
            {
                std::cerr << "Error forcing the mode to MANUAL" << std::endl;
                return r;
            }
        }
        // Need this when we either restart or come back from reset
        r = writeData(cv_TimeOwnerFile, ownerStr(iv_CurrTimeOwner));
    }
    else
    {
        std::cout <<"Deferring update until system state allows it"
                  << std::endl;
    }

    return r;
}

// Accepts the time mode and makes necessary changes to timedate1
int TimeConfig::modifyNtpSettings(const timeModes& newTimeMode)
{
    auto ntpChangeOp = 0;

    // Pass '1' -or- '0' to SetNTP method indicating Enable/Disable
    ntpChangeOp = (newTimeMode == timeModes::NTP) ? 1 : 0;

    std::cout <<"Applying NTP setting..." << std::endl;

    auto r = sd_bus_call_method(iv_dbus,
                                "org.freedesktop.timedate1",
                                "/org/freedesktop/timedate1",
                                "org.freedesktop.timedate1",
                                "SetNTP",
                                nullptr,
                                nullptr,    // timedate1 does not return response
                                "bb",
                                ntpChangeOp,       // '1' means Enable
                                0);              // '0' meaning no policy-kit
    if (r < 0)
    {
        std::cerr <<"Error: " << strerror(-r)
                  << "changing time Mode" << std::endl;
    }
    else
    {
        std::cout << "SUCCESS. NTP setting is now: " <<
                  ((ntpChangeOp) ? "Enabled" : "Disabled");

        // TODO : https://github.com/openbmc/phosphor-time-manager/issues/1
        if (ntpChangeOp)
        {
            r = system("systemctl restart systemd-timesyncd &");
        }
        else
        {
            r = system("systemctl stop systemd-timesyncd &");
        }
    }
    return r;
}

// Reads all the saved data from the last run
int TimeConfig::readPersistentData()
{
    // If we are coming back from a reset reload, then need to
    // read what was the last successful Mode and Owner.
    auto savedTimeMode = readData<std::string>(cv_TimeModeFile);
    if (!savedTimeMode.empty())
    {
        iv_CurrTimeMode = getTimeMode(savedTimeMode.c_str());
        std::cout <<"Last known time_mode: "
                  << savedTimeMode.c_str() << std::endl;
    }

    auto savedTimeOwner = readData<std::string>(cv_TimeOwnerFile);
    if (!savedTimeOwner.empty())
    {
        iv_CurrTimeOwner = getTimeOwner(savedTimeOwner.c_str());
        std::cout <<"Last known time_owner: "
                  << savedTimeOwner.c_str() << std::endl;
    }

    auto savedDhcpNtp = readData<std::string>(cv_DhcpNtpFile);
    if (!savedDhcpNtp.empty())
    {
        iv_CurrDhcpNtp = savedDhcpNtp;
        std::cout <<"Last known use_dhcp_ntp: "
                  << iv_CurrDhcpNtp.c_str() << std::endl;
    }
    else
    {
        // This seems to be the first time.
        std::cerr <<"Empty DhcpNtp string" << std::endl;
        iv_CurrDhcpNtp = "yes";
    }

    // Doing this here to make sure 'pgood' is read and handled
    // first before anything.
    auto pgood = getPowerSetting("pgood");
    if (!pgood.compare("0"))
    {
        std::cout << "Changing settings *allowed* now" << std::endl;
        iv_SettingChangeAllowed = true;
    }
    return 0;
}

std::string TimeConfig::getTimeOwnerSetting(const char* path)
{
    sdbusplus::bus::bus bus{iv_dbus};
    auto method = bus.new_method_call(
                      settings.service(settings.timeOwner,
                          settings::timeOwnerIntf).c_str(),
                      path,
                      "org.freedesktop.DBus.Properties",
                      "Get");
    method.append(settings::timeOwnerIntf, "TimeOwner");
    auto reply = bus.call(method);
    if (reply.is_method_error())
    {
        log<level::ERR>("Error in TimeOwner Get");
        elog<InternalFailure>();
    }

    sdbusplus::message::variant<std::string> result;
    reply.read(result);
    // TODO via openbmc/openbmc#668 - because the old org.openbmc settings
    // interfaces defined the time settings as strings, the code in this file
    // is based around that fact. We use enums in the new settings interfaces,
    // so code in this file can be changed to work with enums instead. That's
    // being covered by the time manager rework (#668). For now, converting the
    // settings to the string format that this object expects it to be.
    // For eg, convert "xyz.openbmc_project.Time.Owner.Split" to "SPLIT".
    auto setting = result.get<std::string>();
    return internal::setting::dbusToNative(std::move(setting));
}

std::string TimeConfig::getTimeSyncMethodSetting(const char* path)
{
    sdbusplus::bus::bus bus{iv_dbus};
    auto method = bus.new_method_call(
                      settings.service(settings.timeSyncMethod,
                          settings::timeSyncIntf).c_str(),
                      path,
                      "org.freedesktop.DBus.Properties",
                      "Get");
    method.append(settings::timeSyncIntf, "TimeSyncMethod");
    auto reply = bus.call(method);
    if (reply.is_method_error())
    {
        log<level::ERR>("Error in TimeSyncMethod Get");
        elog<InternalFailure>();
    }

    sdbusplus::message::variant<std::string> result;
    reply.read(result);
    auto setting = result.get<std::string>();
    return internal::setting::dbusToNative(std::move(setting));
}

int TimeConfig::settingsChanged(sdbusplus::message::message& msg)
{
    using Interface = std::string;
    using Property = std::string;
    using Value = std::string;
    using Properties = std::map<Property, sdbusplus::message::variant<Value>>;

    Interface interface;
    Properties properties;

    msg.read(interface, properties);

    auto path = msg.get_path();
    for(const auto& p : properties)
    {
        auto setting = p.second.get<std::string>();
        updatePropertyVal(path,
                          internal::setting::dbusToNative(std::move(setting)));
    }

    return 0;
}