/*
// 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 "ADCSensor.hpp"
#include "Thresholds.hpp"
#include "Utils.hpp"
#include "VariantVisitors.hpp"

#include <boost/algorithm/string/case_conv.hpp>
#include <boost/asio/error.hpp>
#include <boost/asio/io_context.hpp>
#include <boost/asio/post.hpp>
#include <boost/asio/steady_timer.hpp>
#include <boost/container/flat_map.hpp>
#include <boost/container/flat_set.hpp>
#include <gpiod.hpp>
#include <sdbusplus/asio/connection.hpp>
#include <sdbusplus/asio/object_server.hpp>
#include <sdbusplus/bus.hpp>
#include <sdbusplus/bus/match.hpp>
#include <sdbusplus/message.hpp>
#include <sdbusplus/message/native_types.hpp>

#include <array>
#include <chrono>
#include <cstddef>
#include <filesystem>
#include <fstream>
#include <functional>
#include <iostream>
#include <memory>
#include <optional>
#include <regex>
#include <stdexcept>
#include <string>
#include <utility>
#include <variant>
#include <vector>

static constexpr bool debug = false;
static constexpr float pollRateDefault = 0.5;
static constexpr float gpioBridgeSetupTimeDefault = 0.02;

namespace fs = std::filesystem;

static constexpr auto sensorTypes{std::to_array<const char*>({"ADC"})};
static std::regex inputRegex(R"(in(\d+)_input)");

static boost::container::flat_map<size_t, bool> cpuPresence;

enum class UpdateType
{
    init,
    cpuPresenceChange
};

// filter out adc from any other voltage sensor
bool isAdc(const fs::path& parentPath)
{
    fs::path namePath = parentPath / "name";

    std::ifstream nameFile(namePath);
    if (!nameFile.good())
    {
        std::cerr << "Failure reading " << namePath.string() << "\n";
        return false;
    }

    std::string name;
    std::getline(nameFile, name);

    return name == "iio_hwmon";
}

void createSensors(
    boost::asio::io_context& io, sdbusplus::asio::object_server& objectServer,
    boost::container::flat_map<std::string, std::shared_ptr<ADCSensor>>&
        sensors,
    std::shared_ptr<sdbusplus::asio::connection>& dbusConnection,
    const std::shared_ptr<boost::container::flat_set<std::string>>&
        sensorsChanged,
    UpdateType updateType)
{
    auto getter = std::make_shared<GetSensorConfiguration>(
        dbusConnection,
        [&io, &objectServer, &sensors, &dbusConnection, sensorsChanged,
         updateType](const ManagedObjectType& sensorConfigurations) {
        bool firstScan = sensorsChanged == nullptr;
        std::vector<fs::path> paths;
        if (!findFiles(fs::path("/sys/class/hwmon"), R"(in\d+_input)", paths))
        {
            std::cerr << "No adc sensors in system\n";
            return;
        }

        // iterate through all found adc sensors, and try to match them with
        // configuration
        for (auto& path : paths)
        {
            if (!isAdc(path.parent_path()))
            {
                continue;
            }
            std::smatch match;
            std::string pathStr = path.string();

            std::regex_search(pathStr, match, inputRegex);
            std::string indexStr = *(match.begin() + 1);

            // convert to 0 based
            size_t index = std::stoul(indexStr) - 1;

            const SensorData* sensorData = nullptr;
            const std::string* interfacePath = nullptr;
            const std::pair<std::string, SensorBaseConfigMap>*
                baseConfiguration = nullptr;
            for (const auto& [path, cfgData] : sensorConfigurations)
            {
                // clear it out each loop
                baseConfiguration = nullptr;

                // find base configuration
                for (const char* type : sensorTypes)
                {
                    auto sensorBase = cfgData.find(configInterfaceName(type));
                    if (sensorBase != cfgData.end())
                    {
                        baseConfiguration = &(*sensorBase);
                        break;
                    }
                }
                if (baseConfiguration == nullptr)
                {
                    continue;
                }
                auto findIndex = baseConfiguration->second.find("Index");
                if (findIndex == baseConfiguration->second.end())
                {
                    std::cerr << "Base configuration missing Index"
                              << baseConfiguration->first << "\n";
                    continue;
                }

                unsigned int number = std::visit(VariantToUnsignedIntVisitor(),
                                                 findIndex->second);

                if (number != index)
                {
                    continue;
                }

                sensorData = &cfgData;
                interfacePath = &path.str;
                break;
            }
            if (sensorData == nullptr)
            {
                if constexpr (debug)
                {
                    std::cerr << "failed to find match for " << path.string()
                              << "\n";
                }
                continue;
            }

            if (baseConfiguration == nullptr)
            {
                std::cerr << "error finding base configuration for"
                          << path.string() << "\n";
                continue;
            }

            auto findSensorName = baseConfiguration->second.find("Name");
            if (findSensorName == baseConfiguration->second.end())
            {
                std::cerr << "could not determine configuration name for "
                          << path.string() << "\n";
                continue;
            }
            std::string sensorName =
                std::get<std::string>(findSensorName->second);

            // on rescans, only update sensors we were signaled by
            auto findSensor = sensors.find(sensorName);
            if (!firstScan && findSensor != sensors.end())
            {
                bool found = false;
                for (auto it = sensorsChanged->begin();
                     it != sensorsChanged->end(); it++)
                {
                    if (findSensor->second &&
                        it->ends_with(findSensor->second->name))
                    {
                        sensorsChanged->erase(it);
                        findSensor->second = nullptr;
                        found = true;
                        break;
                    }
                }
                if (!found)
                {
                    continue;
                }
            }

            auto findCPU = baseConfiguration->second.find("CPURequired");
            if (findCPU != baseConfiguration->second.end())
            {
                size_t index = std::visit(VariantToIntVisitor(),
                                          findCPU->second);
                auto presenceFind = cpuPresence.find(index);
                if (presenceFind == cpuPresence.end())
                {
                    continue; // no such cpu
                }
                if (!presenceFind->second)
                {
                    continue; // cpu not installed
                }
            }
            else if (updateType == UpdateType::cpuPresenceChange)
            {
                continue;
            }

            std::vector<thresholds::Threshold> sensorThresholds;
            if (!parseThresholdsFromConfig(*sensorData, sensorThresholds))
            {
                std::cerr << "error populating thresholds for " << sensorName
                          << "\n";
            }

            auto findScaleFactor =
                baseConfiguration->second.find("ScaleFactor");
            float scaleFactor = 1.0;
            if (findScaleFactor != baseConfiguration->second.end())
            {
                scaleFactor = std::visit(VariantToFloatVisitor(),
                                         findScaleFactor->second);
                // scaleFactor is used in division
                if (scaleFactor == 0.0F)
                {
                    scaleFactor = 1.0;
                }
            }

            float pollRate = getPollRate(baseConfiguration->second,
                                         pollRateDefault);
            PowerState readState = getPowerState(baseConfiguration->second);

            auto& sensor = sensors[sensorName];
            sensor = nullptr;

            std::optional<BridgeGpio> bridgeGpio;
            for (const auto& [key, cfgMap] : *sensorData)
            {
                if (key.find("BridgeGpio") != std::string::npos)
                {
                    auto findName = cfgMap.find("Name");
                    if (findName != cfgMap.end())
                    {
                        std::string gpioName = std::visit(
                            VariantToStringVisitor(), findName->second);

                        int polarity = gpiod::line::ACTIVE_HIGH;
                        auto findPolarity = cfgMap.find("Polarity");
                        if (findPolarity != cfgMap.end())
                        {
                            if (std::string("Low") ==
                                std::visit(VariantToStringVisitor(),
                                           findPolarity->second))
                            {
                                polarity = gpiod::line::ACTIVE_LOW;
                            }
                        }

                        float setupTime = gpioBridgeSetupTimeDefault;
                        auto findSetupTime = cfgMap.find("SetupTime");
                        if (findSetupTime != cfgMap.end())
                        {
                            setupTime = std::visit(VariantToFloatVisitor(),
                                                   findSetupTime->second);
                        }

                        bridgeGpio = BridgeGpio(gpioName, polarity, setupTime);
                    }

                    break;
                }
            }

            sensor = std::make_shared<ADCSensor>(
                path.string(), objectServer, dbusConnection, io, sensorName,
                std::move(sensorThresholds), scaleFactor, pollRate, readState,
                *interfacePath, std::move(bridgeGpio));
            sensor->setupRead();
        }
    });

    getter->getConfiguration(
        std::vector<std::string>{sensorTypes.begin(), sensorTypes.end()});
}

int main()
{
    boost::asio::io_context io;
    auto systemBus = std::make_shared<sdbusplus::asio::connection>(io);
    sdbusplus::asio::object_server objectServer(systemBus, true);
    objectServer.add_manager("/xyz/openbmc_project/sensors");

    systemBus->request_name("xyz.openbmc_project.ADCSensor");
    boost::container::flat_map<std::string, std::shared_ptr<ADCSensor>> sensors;
    auto sensorsChanged =
        std::make_shared<boost::container::flat_set<std::string>>();

    boost::asio::post(io, [&]() {
        createSensors(io, objectServer, sensors, systemBus, nullptr,
                      UpdateType::init);
    });

    boost::asio::steady_timer filterTimer(io);
    std::function<void(sdbusplus::message_t&)> eventHandler =
        [&](sdbusplus::message_t& message) {
        if (message.is_method_error())
        {
            std::cerr << "callback method error\n";
            return;
        }
        sensorsChanged->insert(message.get_path());
        // this implicitly cancels the timer
        filterTimer.expires_after(std::chrono::seconds(1));

        filterTimer.async_wait([&](const boost::system::error_code& ec) {
            if (ec == boost::asio::error::operation_aborted)
            {
                /* we were canceled*/
                return;
            }
            if (ec)
            {
                std::cerr << "timer error\n";
                return;
            }
            createSensors(io, objectServer, sensors, systemBus, sensorsChanged,
                          UpdateType::init);
        });
    };

    boost::asio::steady_timer cpuFilterTimer(io);
    std::function<void(sdbusplus::message_t&)> cpuPresenceHandler =
        [&](sdbusplus::message_t& message) {
        std::string path = message.get_path();
        boost::to_lower(path);

        sdbusplus::message::object_path cpuPath(path);
        std::string cpuName = cpuPath.filename();
        if (!cpuName.starts_with("cpu"))
        {
            return; // not interested
        }
        size_t index = 0;
        try
        {
            index = std::stoi(path.substr(path.size() - 1));
        }
        catch (const std::invalid_argument&)
        {
            std::cerr << "Found invalid path " << path << "\n";
            return;
        }

        std::string objectName;
        boost::container::flat_map<std::string, std::variant<bool>> values;
        message.read(objectName, values);
        auto findPresence = values.find("Present");
        if (findPresence != values.end())
        {
            cpuPresence[index] = std::get<bool>(findPresence->second);
        }

        // this implicitly cancels the timer
        cpuFilterTimer.expires_after(std::chrono::seconds(1));

        cpuFilterTimer.async_wait([&](const boost::system::error_code& ec) {
            if (ec == boost::asio::error::operation_aborted)
            {
                /* we were canceled*/
                return;
            }
            if (ec)
            {
                std::cerr << "timer error\n";
                return;
            }
            createSensors(io, objectServer, sensors, systemBus, nullptr,
                          UpdateType::cpuPresenceChange);
        });
    };

    std::vector<std::unique_ptr<sdbusplus::bus::match_t>> matches =
        setupPropertiesChangedMatches(*systemBus, sensorTypes, eventHandler);
    matches.emplace_back(std::make_unique<sdbusplus::bus::match_t>(
        static_cast<sdbusplus::bus_t&>(*systemBus),
        "type='signal',member='PropertiesChanged',path_namespace='" +
            std::string(cpuInventoryPath) +
            "',arg0namespace='xyz.openbmc_project.Inventory.Item'",
        cpuPresenceHandler));

    setupManufacturingModeMatch(*systemBus);
    io.run();
}