/**
 * Copyright © 2016 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 <functional>
#include <iostream>
#include <memory>
#include <cstdlib>
#include <cstring>
#include <string>
#include <unordered_set>

#include <phosphor-logging/elog-errors.hpp>
#include "config.h"
#include "env.hpp"
#include "fan_pwm.hpp"
#include "fan_speed.hpp"
#include "hwmon.hpp"
#include "sensorset.hpp"
#include "sysfs.hpp"
#include "mainloop.hpp"
#include "targets.hpp"
#include "thresholds.hpp"

#include <xyz/openbmc_project/Sensor/Device/error.hpp>

using namespace phosphor::logging;

// Initialization for Warning Objects
decltype(Thresholds<WarningObject>::setLo) Thresholds<WarningObject>::setLo =
    &WarningObject::warningLow;
decltype(Thresholds<WarningObject>::setHi) Thresholds<WarningObject>::setHi =
    &WarningObject::warningHigh;
decltype(Thresholds<WarningObject>::getLo) Thresholds<WarningObject>::getLo =
    &WarningObject::warningLow;
decltype(Thresholds<WarningObject>::getHi) Thresholds<WarningObject>::getHi =
    &WarningObject::warningHigh;
decltype(Thresholds<WarningObject>::alarmLo) Thresholds<WarningObject>::alarmLo =
    &WarningObject::warningAlarmLow;
decltype(Thresholds<WarningObject>::alarmHi) Thresholds<WarningObject>::alarmHi =
    &WarningObject::warningAlarmHigh;

// Initialization for Critical Objects
decltype(Thresholds<CriticalObject>::setLo) Thresholds<CriticalObject>::setLo =
    &CriticalObject::criticalLow;
decltype(Thresholds<CriticalObject>::setHi) Thresholds<CriticalObject>::setHi =
    &CriticalObject::criticalHigh;
decltype(Thresholds<CriticalObject>::getLo) Thresholds<CriticalObject>::getLo =
    &CriticalObject::criticalLow;
decltype(Thresholds<CriticalObject>::getHi) Thresholds<CriticalObject>::getHi =
    &CriticalObject::criticalHigh;
decltype(Thresholds<CriticalObject>::alarmLo) Thresholds<CriticalObject>::alarmLo =
    &CriticalObject::criticalAlarmLow;
decltype(Thresholds<CriticalObject>::alarmHi) Thresholds<CriticalObject>::alarmHi =
    &CriticalObject::criticalAlarmHigh;

// The gain and offset to adjust a value
struct valueAdjust
{
    double gain = 1.0;
    int offset = 0;
    std::unordered_set<int> rmRCs;
};

// Store the valueAdjust for sensors
std::map<SensorSet::key_type, valueAdjust> sensorAdjusts;

void addRemoveRCs(const SensorSet::key_type& sensor,
                  const std::string& rcList)
{
    if (rcList.empty())
    {
        return;
    }

    // Convert to a char* for strtok
    std::vector<char> rmRCs(rcList.c_str(),
                            rcList.c_str() + rcList.size() + 1);
    auto rmRC = std::strtok(&rmRCs[0], ", ");
    while (rmRC != nullptr)
    {
        try
        {
            sensorAdjusts[sensor].rmRCs.insert(std::stoi(rmRC));
        }
        catch (const std::logic_error& le)
        {
            // Unable to convert to int, continue to next token
            std::string name = sensor.first + "_" + sensor.second;
            log<level::INFO>("Unable to convert sensor removal return code",
                             entry("SENSOR=%s", name.c_str()),
                             entry("RC=%s", rmRC),
                             entry("EXCEPTION=%s", le.what()));
        }
        rmRC = std::strtok(nullptr, ", ");
    }
}

int64_t adjustValue(const SensorSet::key_type& sensor, int64_t value)
{
// Because read doesn't have an out pointer to store errors.
// let's assume negative values are errors if they have this
// set.
#ifdef NEGATIVE_ERRNO_ON_FAIL
    if (value < 0)
    {
        return value;
    }
#endif

    const auto& it = sensorAdjusts.find(sensor);
    if (it != sensorAdjusts.end())
    {
        // Adjust based on gain and offset
        value = static_cast<decltype(value)>(
                    static_cast<double>(value) * it->second.gain
                        + it->second.offset);
    }
    return value;
}

auto addValue(const SensorSet::key_type& sensor,
              const RetryIO& retryIO,
              sysfs::hwmonio::HwmonIO& ioAccess,
              ObjectInfo& info,
              bool isOCC = false)
{
    static constexpr bool deferSignals = true;

    // Get the initial value for the value interface.
    auto& bus = *std::get<sdbusplus::bus::bus*>(info);
    auto& obj = std::get<Object>(info);
    auto& objPath = std::get<std::string>(info);

    auto senRmRCs = env::getEnv("REMOVERCS", sensor);
    // Add sensor removal return codes defined per sensor
    addRemoveRCs(sensor, senRmRCs);

    // Retry for up to a second if device is busy
    // or has a transient error.
    int64_t val = ioAccess.read(
            sensor.first,
            sensor.second,
            hwmon::entry::cinput,
            std::get<size_t>(retryIO),
            std::get<std::chrono::milliseconds>(retryIO),
            isOCC);

    auto gain = env::getEnv("GAIN", sensor);
    if (!gain.empty())
    {
        sensorAdjusts[sensor].gain = std::stod(gain);
    }

    auto offset = env::getEnv("OFFSET", sensor);
    if (!offset.empty())
    {
        sensorAdjusts[sensor].offset = std::stoi(offset);
    }

    val = adjustValue(sensor, val);

    auto iface = std::make_shared<ValueObject>(bus, objPath.c_str(), deferSignals);
    iface->value(val);

    hwmon::Attributes attrs;
    if (hwmon::getAttributes(sensor.first, attrs))
    {
        iface->unit(hwmon::getUnit(attrs));
        iface->scale(hwmon::getScale(attrs));
    }

    auto maxValue = env::getEnv("MAXVALUE", sensor);
    if(!maxValue.empty())
    {
        iface->maxValue(std::stoll(maxValue));
    }
    auto minValue = env::getEnv("MINVALUE", sensor);
    if(!minValue.empty())
    {
        iface->minValue(std::stoll(minValue));
    }

    obj[InterfaceType::VALUE] = iface;
    return iface;
}

std::string MainLoop::getID(SensorSet::container_t::const_reference sensor)
{
    std::string id;

    /*
     * Check if the value of the MODE_<item><X> env variable for the sensor
     * is "label", then read the sensor number from the <item><X>_label
     * file. The name of the DBUS object would be the value of the env
     * variable LABEL_<item><sensorNum>. If the MODE_<item><X> env variable
     * doesn't exist, then the name of DBUS object is the value of the env
     * variable LABEL_<item><X>.
     */
    auto mode = env::getEnv("MODE", sensor.first);
    if (!mode.compare(hwmon::entry::label))
    {
        id = env::getIndirectID(
                _hwmonRoot + '/' + _instance + '/', sensor.first);

        if (id.empty())
        {
            return id;
        }
    }

    // Use the ID we looked up above if there was one,
    // otherwise use the standard one.
    id = (id.empty()) ? sensor.first.second : id;

    return id;
}

SensorIdentifiers MainLoop::getIdentifiers(
        SensorSet::container_t::const_reference sensor)
{
    std::string id = getID(sensor);
    std::string label;

    if (!id.empty())
    {
        // Ignore inputs without a label.
        label = env::getEnv("LABEL", sensor.first.first, id);
    }

    return std::make_tuple(std::move(id),
                           std::move(label));
}

/**
 * Reads the environment parameters of a sensor and creates an object with
 * atleast the `Value` interface, otherwise returns without creating the object.
 * If the `Value` interface is successfully created, by reading the sensor's
 * corresponding sysfs file's value, the additional interfaces for the sensor
 * are created and the InterfacesAdded signal is emitted. The sensor is then
 * moved to the list for sensor state monitoring within the main loop.
 */
void MainLoop::getObject(SensorSet::container_t::const_reference sensor)
{
    auto properties = getIdentifiers(sensor);
    if (std::get<sensorID>(properties).empty() ||
        std::get<sensorLabel>(properties).empty())
    {
        return;
    }

    hwmon::Attributes attrs;
    if (!hwmon::getAttributes(sensor.first.first, attrs))
    {
        return;
    }

    // Get list of return codes for removing sensors on device
    auto devRmRCs = env::getEnv("REMOVERCS");
    // Add sensor removal return codes defined at the device level
    addRemoveRCs(sensor.first, devRmRCs);

    std::string objectPath{_root};
    objectPath.append(1, '/');
    objectPath.append(hwmon::getNamespace(attrs));
    objectPath.append(1, '/');
    objectPath.append(std::get<sensorLabel>(properties));

    ObjectInfo info(&_bus, std::move(objectPath), Object());
    RetryIO retryIO(sysfs::hwmonio::retries, sysfs::hwmonio::delay);
    if (rmSensors.find(sensor.first) != rmSensors.end())
    {
        // When adding a sensor that was purposely removed,
        // don't retry on errors when reading its value
        std::get<size_t>(retryIO) = 0;
    }
    auto valueInterface = static_cast<
            std::shared_ptr<ValueObject>>(nullptr);
    try
    {
        valueInterface = addValue(sensor.first, retryIO, ioAccess, info,
                _isOCC);
    }
    catch (const std::system_error& e)
    {
        auto file = sysfs::make_sysfs_path(
                ioAccess.path(),
                sensor.first.first,
                sensor.first.second,
                hwmon::entry::cinput);
#ifndef REMOVE_ON_FAIL
        // Check sensorAdjusts for sensor removal RCs
        const auto& it = sensorAdjusts.find(sensor.first);
        if (it != sensorAdjusts.end())
        {
            auto rmRCit = it->second.rmRCs.find(e.code().value());
            if (rmRCit != std::end(it->second.rmRCs))
            {
                // Return code found in sensor return code removal list
                if (rmSensors.find(sensor.first) == rmSensors.end())
                {
                    // Trace for sensor not already removed from dbus
                    log<level::INFO>("Sensor not added to dbus for read fail",
                            entry("FILE=%s", file.c_str()),
                            entry("RC=%d", e.code().value()));
                    rmSensors[std::move(sensor.first)] =
                            std::move(sensor.second);
                }
                return;
            }
        }
#endif
        using namespace sdbusplus::xyz::openbmc_project::
                Sensor::Device::Error;
        report<ReadFailure>(
            xyz::openbmc_project::Sensor::Device::
                ReadFailure::CALLOUT_ERRNO(e.code().value()),
            xyz::openbmc_project::Sensor::Device::
                ReadFailure::CALLOUT_DEVICE_PATH(_devPath.c_str()));

        log<level::INFO>("Logging failing sysfs file",
                entry("FILE=%s", file.c_str()));
#ifdef REMOVE_ON_FAIL
        return; /* skip adding this sensor for now. */
#else
        exit(EXIT_FAILURE);
#endif
    }
    auto sensorValue = valueInterface->value();
    addThreshold<WarningObject>(sensor.first.first,
                                std::get<sensorID>(properties),
                                sensorValue,
                                info);
    addThreshold<CriticalObject>(sensor.first.first,
                                 std::get<sensorID>(properties),
                                 sensorValue,
                                 info);

    auto target = addTarget<hwmon::FanSpeed>(
            sensor.first, ioAccess, _devPath, info);
    if (target)
    {
        target->enable();
    }
    addTarget<hwmon::FanPwm>(sensor.first, ioAccess, _devPath, info);

    // All the interfaces have been created.  Go ahead
    // and emit InterfacesAdded.
    valueInterface->emit_object_added();

    auto value = std::make_tuple(
                     std::move(sensor.second),
                     std::move(std::get<sensorLabel>(properties)),
                     std::move(info));

    state[std::move(sensor.first)] = std::move(value);
}

MainLoop::MainLoop(
    sdbusplus::bus::bus&& bus,
    const std::string& path,
    const std::string& devPath,
    const char* prefix,
    const char* root)
    : _bus(std::move(bus)),
      _manager(_bus, root),
      _hwmonRoot(),
      _instance(),
      _devPath(devPath),
      _prefix(prefix),
      _root(root),
      state(),
      ioAccess(path)
{
    if (path.find("occ") != std::string::npos)
    {
        _isOCC = true;
    }

    // Strip off any trailing slashes.
    std::string p = path;
    while (!p.empty() && p.back() == '/')
    {
        p.pop_back();
    }

    // Given the furthest right /, set instance to
    // the basename, and hwmonRoot to the leading path.
    auto n = p.rfind('/');
    if (n != std::string::npos)
    {
        _instance.assign(p.substr(n + 1));
        _hwmonRoot.assign(p.substr(0, n));
    }

    assert(!_instance.empty());
    assert(!_hwmonRoot.empty());
}

void MainLoop::shutdown() noexcept
{
    timer->state(phosphor::hwmon::timer::OFF);
    sd_event_exit(loop, 0);
    loop = nullptr;
}

void MainLoop::run()
{
    init();

    sd_event_default(&loop);

    std::function<void()> callback(std::bind(
            &MainLoop::read, this));
    try
    {
        timer = std::make_unique<phosphor::hwmon::Timer>(
                                 loop, callback,
                                 std::chrono::microseconds(_interval),
                                 phosphor::hwmon::timer::ON);

        // TODO: Issue#6 - Optionally look at polling interval sysfs entry.

        // TODO: Issue#7 - Should probably periodically check the SensorSet
        //       for new entries.

        _bus.attach_event(loop, SD_EVENT_PRIORITY_IMPORTANT);
        sd_event_loop(loop);
    }
    catch (const std::system_error& e)
    {
        log<level::ERR>("Error in sysfs polling loop",
                        entry("ERROR=%s", e.what()));
        throw;
    }
}

void MainLoop::init()
{
    // Check sysfs for available sensors.
    auto sensors = std::make_unique<SensorSet>(_hwmonRoot + '/' + _instance);

    for (auto& i : *sensors)
    {
        getObject(i);
    }

    /* If there are no sensors specified by labels, exit. */
    if (0 == state.size())
    {
        exit(0);
    }

    {
        std::string busname{_prefix};
        busname.append(1, '-');
        busname.append(
                std::to_string(std::hash<decltype(_devPath)>{}(_devPath)));
        busname.append(".Hwmon1");
        _bus.request_name(busname.c_str());
    }

    {
        auto interval = env::getEnv("INTERVAL");
        if (!interval.empty())
        {
            _interval = std::strtoull(interval.c_str(), NULL, 10);
        }
    }
}

void MainLoop::read()
{
    // TODO: Issue#3 - Need to make calls to the dbus sensor cache here to
    //       ensure the objects all exist?

    // Iterate through all the sensors.
    for (auto& i : state)
    {
        auto& attrs = std::get<0>(i.second);
        if (attrs.find(hwmon::entry::input) != attrs.end())
        {
            // Read value from sensor.
            int64_t value;
            std::string input = hwmon::entry::cinput;
            if (i.first.first == "pwm") {
                input = "";
            }

            try
            {
                // Retry for up to a second if device is busy
                // or has a transient error.

                value = ioAccess.read(
                        i.first.first,
                        i.first.second,
                        input,
                        sysfs::hwmonio::retries,
                        sysfs::hwmonio::delay,
                        _isOCC);

                value = adjustValue(i.first, value);

                auto& objInfo = std::get<ObjectInfo>(i.second);
                auto& obj = std::get<Object>(objInfo);

                for (auto& iface : obj)
                {
                    auto valueIface = std::shared_ptr<ValueObject>();
                    auto warnIface = std::shared_ptr<WarningObject>();
                    auto critIface = std::shared_ptr<CriticalObject>();

                    switch (iface.first)
                    {
                        case InterfaceType::VALUE:
                            valueIface = std::experimental::any_cast<std::shared_ptr<ValueObject>>
                                        (iface.second);
                            valueIface->value(value);
                            break;
                        case InterfaceType::WARN:
                            checkThresholds<WarningObject>(iface.second, value);
                            break;
                        case InterfaceType::CRIT:
                            checkThresholds<CriticalObject>(iface.second, value);
                            break;
                        default:
                            break;
                    }
                }
            }
            catch (const std::system_error& e)
            {
                auto file = sysfs::make_sysfs_path(
                        ioAccess.path(),
                        i.first.first,
                        i.first.second,
                        hwmon::entry::cinput);
#ifndef REMOVE_ON_FAIL
                // Check sensorAdjusts for sensor removal RCs
                const auto& it = sensorAdjusts.find(i.first);
                if (it != sensorAdjusts.end())
                {
                    auto rmRCit = it->second.rmRCs.find(e.code().value());
                    if (rmRCit != std::end(it->second.rmRCs))
                    {
                        // Return code found in sensor return code removal list
                        if (rmSensors.find(i.first) == rmSensors.end())
                        {
                            // Trace for sensor not already removed from dbus
                            log<level::INFO>(
                                    "Remove sensor from dbus for read fail",
                                    entry("FILE=%s", file.c_str()),
                                    entry("RC=%d", e.code().value()));
                            // Mark this sensor to be removed from dbus
                            rmSensors[i.first] = std::get<0>(i.second);
                        }
                        continue;
                    }
                }
#endif
                using namespace sdbusplus::xyz::openbmc_project::
                    Sensor::Device::Error;
                report<ReadFailure>(
                        xyz::openbmc_project::Sensor::Device::
                            ReadFailure::CALLOUT_ERRNO(e.code().value()),
                        xyz::openbmc_project::Sensor::Device::
                            ReadFailure::CALLOUT_DEVICE_PATH(
                                _devPath.c_str()));

                log<level::INFO>("Logging failing sysfs file",
                        entry("FILE=%s", file.c_str()));

#ifdef REMOVE_ON_FAIL
                rmSensors[i.first] = std::get<0>(i.second);
#else
                exit(EXIT_FAILURE);
#endif
            }
        }
    }

    // Remove any sensors marked for removal
    for (auto& i : rmSensors)
    {
        state.erase(i.first);
    }

#ifndef REMOVE_ON_FAIL
    // Attempt to add any sensors that were removed
    auto it = rmSensors.begin();
    while (it != rmSensors.end())
    {
        if (state.find(it->first) == state.end())
        {
            SensorSet::container_t::value_type ssValueType =
                    std::make_pair(it->first, it->second);
            getObject(ssValueType);
            if (state.find(it->first) != state.end())
            {
                // Sensor object added, erase entry from removal list
                auto file = sysfs::make_sysfs_path(
                        ioAccess.path(),
                        it->first.first,
                        it->first.second,
                        hwmon::entry::cinput);
                log<level::INFO>(
                        "Added sensor to dbus after successful read",
                        entry("FILE=%s", file.c_str()));
                it = rmSensors.erase(it);
            }
            else
            {
                ++it;
            }
        }
        else
        {
            // Sanity check to remove sensors that were re-added
            it = rmSensors.erase(it);
        }
    }
#endif
}

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