/*
// Copyright (c) 2017 Intel 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 <unistd.h>

#include <ADCSensor.hpp>
#include <boost/algorithm/string/predicate.hpp>
#include <boost/algorithm/string/replace.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>
#include <iostream>
#include <limits>
#include <sdbusplus/asio/connection.hpp>
#include <sdbusplus/asio/object_server.hpp>
#include <string>

static constexpr unsigned int sensorPollMs = 500;
static constexpr size_t warnAfterErrorCount = 10;

// scaling factor from hwmon
static constexpr unsigned int sensorScaleFactor = 1000;

static constexpr double roundFactor = 10000; // 3 decimal places
static constexpr double maxReading = 20;
static constexpr double minReading = 0;

ADCSensor::ADCSensor(const std::string &path,
                     sdbusplus::asio::object_server &objectServer,
                     std::shared_ptr<sdbusplus::asio::connection> &conn,
                     boost::asio::io_service &io, const std::string &sensorName,
                     std::vector<thresholds::Threshold> &&_thresholds,
                     const double scaleFactor,
                     const std::string &sensorConfiguration) :
    Sensor(boost::replace_all_copy(sensorName, " ", "_"), path,
           std::move(_thresholds), sensorConfiguration,
           "xyz.openbmc_project.Configuration.ADC", maxReading, minReading),
    objServer(objectServer), scaleFactor(scaleFactor),
    inputDev(io, open(path.c_str(), O_RDONLY)), waitTimer(io), errCount(0)
{
    sensorInterface = objectServer.add_interface(
        "/xyz/openbmc_project/sensors/voltage/" + name,
        "xyz.openbmc_project.Sensor.Value");
    if (thresholds::hasWarningInterface(thresholds))
    {
        thresholdInterfaceWarning = objectServer.add_interface(
            "/xyz/openbmc_project/sensors/voltage/" + name,
            "xyz.openbmc_project.Sensor.Threshold.Warning");
    }
    if (thresholds::hasCriticalInterface(thresholds))
    {
        thresholdInterfaceCritical = objectServer.add_interface(
            "/xyz/openbmc_project/sensors/voltage/" + name,
            "xyz.openbmc_project.Sensor.Threshold.Critical");
    }
    setInitialProperties(conn);
    setupRead();
}

ADCSensor::~ADCSensor()
{
    // close the input dev to cancel async operations
    inputDev.close();
    waitTimer.cancel();
    objServer.remove_interface(thresholdInterfaceWarning);
    objServer.remove_interface(thresholdInterfaceCritical);
    objServer.remove_interface(sensorInterface);
}

void ADCSensor::setupRead(void)
{
    boost::asio::async_read_until(
        inputDev, readBuf, '\n',
        [&](const boost::system::error_code &ec,
            std::size_t /*bytes_transfered*/) { handleResponse(ec); });
}

void ADCSensor::handleResponse(const boost::system::error_code &err)
{
    if (err == boost::system::errc::bad_file_descriptor)
    {
        return; // we're being destroyed
    }
    std::istream responseStream(&readBuf);

    if (!err)
    {
        std::string response;
        std::getline(responseStream, response);

        // todo read scaling factors from configuration
        try
        {
            double nvalue = std::stof(response);

            nvalue = (nvalue / sensorScaleFactor) / scaleFactor;
            nvalue = std::round(nvalue * roundFactor) / roundFactor;

            if (!isnan(overriddenValue))
            {
                nvalue = overriddenValue;
            }

            if (nvalue != value)
            {
                updateValue(nvalue);
            }
            errCount = 0;
        }
        catch (std::invalid_argument)
        {
            errCount++;
        }
    }
    else
    {

        errCount++;
    }
    // only print once
    if (errCount == warnAfterErrorCount)
    {
        std::cerr << "Failure to read sensor " << name << " at " << path
                  << " ec:" << err << "\n";
    }

    if (errCount >= warnAfterErrorCount)
    {
        updateValue(0);
    }

    responseStream.clear();
    inputDev.close();
    int fd = open(path.c_str(), O_RDONLY);
    if (fd <= 0)
    {
        return; // we're no longer valid
    }
    inputDev.assign(fd);
    waitTimer.expires_from_now(boost::posix_time::milliseconds(sensorPollMs));
    waitTimer.async_wait([&](const boost::system::error_code &ec) {
        if (ec == boost::asio::error::operation_aborted)
        {
            return; // we're being canceled
        }
        setupRead();
    });
}

void ADCSensor::checkThresholds(void)
{
    thresholds::checkThresholds(this);
}