#include "Thresholds.hpp"

#include "VariantVisitors.hpp"
#include "sensor.hpp"

#include <array>
#include <boost/algorithm/string/replace.hpp>
#include <boost/container/flat_map.hpp>
#include <boost/lexical_cast.hpp>
#include <cmath>
#include <fstream>
#include <iostream>
#include <memory>
#include <stdexcept>
#include <string>
#include <tuple>
#include <utility>
#include <variant>
#include <vector>

static constexpr bool DEBUG = false;
namespace thresholds
{
unsigned int toBusValue(const Level& level)
{
    switch (level)
    {
        case (Level::WARNING):
        {
            return 0;
        }
        case (Level::CRITICAL):
        {
            return 1;
        }
        default:
        {
            return -1;
        }
    }
}

std::string toBusValue(const Direction& direction)
{
    switch (direction)
    {
        case (Direction::LOW):
        {
            return "less than";
        }
        case (Direction::HIGH):
        {
            return "greater than";
        }
        default:
        {
            return "err";
        }
    }
}

bool parseThresholdsFromConfig(
    const SensorData& sensorData,
    std::vector<thresholds::Threshold>& thresholdVector,
    const std::string* matchLabel)
{
    for (const auto& item : sensorData)
    {
        if (item.first.find("Thresholds") == std::string::npos)
        {
            continue;
        }
        if (matchLabel != nullptr)
        {
            auto labelFind = item.second.find("Label");
            if (labelFind == item.second.end())
                continue;
            if (std::visit(VariantToStringVisitor(), labelFind->second) !=
                *matchLabel)
                continue;
        }
        auto directionFind = item.second.find("Direction");
        auto severityFind = item.second.find("Severity");
        auto valueFind = item.second.find("Value");
        if (valueFind == item.second.end() ||
            severityFind == item.second.end() ||
            directionFind == item.second.end())
        {
            std::cerr << "Malformed threshold in configuration\n";
            return false;
        }
        Level level;
        Direction direction;
        if (std::visit(VariantToUnsignedIntVisitor(), severityFind->second) ==
            0)
        {
            level = Level::WARNING;
        }
        else
        {
            level = Level::CRITICAL;
        }
        if (std::visit(VariantToStringVisitor(), directionFind->second) ==
            "less than")
        {
            direction = Direction::LOW;
        }
        else
        {
            direction = Direction::HIGH;
        }
        double val = std::visit(VariantToDoubleVisitor(), valueFind->second);

        thresholdVector.emplace_back(level, direction, val);
    }
    return true;
}

void persistThreshold(const std::string& path, const std::string& baseInterface,
                      const thresholds::Threshold& threshold,
                      std::shared_ptr<sdbusplus::asio::connection>& conn,
                      size_t thresholdCount, const std::string& labelMatch)
{
    for (size_t ii = 0; ii < thresholdCount; ii++)
    {
        std::string thresholdInterface =
            baseInterface + ".Thresholds" + std::to_string(ii);
        conn->async_method_call(
            [&, path, threshold, thresholdInterface, labelMatch](
                const boost::system::error_code& ec,
                const boost::container::flat_map<std::string, BasicVariantType>&
                    result) {
                if (ec)
                {
                    return; // threshold not supported
                }

                if (!labelMatch.empty())
                {
                    auto labelFind = result.find("Label");
                    if (labelFind == result.end())
                    {
                        std::cerr << "No label in threshold configuration\n";
                        return;
                    }
                    std::string label =
                        std::visit(VariantToStringVisitor(), labelFind->second);
                    if (label != labelMatch)
                    {
                        return;
                    }
                }

                auto directionFind = result.find("Direction");
                auto severityFind = result.find("Severity");
                auto valueFind = result.find("Value");
                if (valueFind == result.end() || severityFind == result.end() ||
                    directionFind == result.end())
                {
                    std::cerr << "Malformed threshold in configuration\n";
                    return;
                }
                unsigned int level = std::visit(VariantToUnsignedIntVisitor(),
                                                severityFind->second);

                std::string dir =
                    std::visit(VariantToStringVisitor(), directionFind->second);
                if ((toBusValue(threshold.level) != level) ||
                    (toBusValue(threshold.direction) != dir))
                {
                    return; // not the droid we're looking for
                }

                std::variant<double> value(threshold.value);
                conn->async_method_call(
                    [](const boost::system::error_code& ec) {
                        if (ec)
                        {
                            std::cerr << "Error setting threshold " << ec
                                      << "\n";
                        }
                    },
                    entityManagerName, path, "org.freedesktop.DBus.Properties",
                    "Set", thresholdInterface, "Value", value);
            },
            entityManagerName, path, "org.freedesktop.DBus.Properties",
            "GetAll", thresholdInterface);
    }
}

void updateThresholds(Sensor* sensor)
{
    if (sensor->thresholds.empty())
    {
        return;
    }

    for (const auto& threshold : sensor->thresholds)
    {
        std::shared_ptr<sdbusplus::asio::dbus_interface> interface;
        std::string property;
        if (threshold.level == thresholds::Level::CRITICAL)
        {
            interface = sensor->thresholdInterfaceCritical;
            if (threshold.direction == thresholds::Direction::HIGH)
            {
                property = "CriticalHigh";
            }
            else
            {
                property = "CriticalLow";
            }
        }
        else if (threshold.level == thresholds::Level::WARNING)
        {
            interface = sensor->thresholdInterfaceWarning;
            if (threshold.direction == thresholds::Direction::HIGH)
            {
                property = "WarningHigh";
            }
            else
            {
                property = "WarningLow";
            }
        }
        else
        {
            continue;
        }
        if (!interface)
        {
            continue;
        }
        interface->set_property(property, threshold.value);
    }
}

// Debugging counters
static int cHiTrue = 0;
static int cHiFalse = 0;
static int cHiMidstate = 0;
static int cLoTrue = 0;
static int cLoFalse = 0;
static int cLoMidstate = 0;
static int cDebugThrottle = 0;

static std::vector<std::pair<Threshold, bool>> checkThresholds(Sensor* sensor,
                                                               double value)
{
    std::vector<std::pair<Threshold, bool>> thresholdChanges;
    if (sensor->thresholds.empty())
    {
        return thresholdChanges;
    }

    for (auto& threshold : sensor->thresholds)
    {
        // Use "Schmitt trigger" logic to avoid threshold trigger spam,
        // if value is noisy while hovering very close to a threshold.
        // When a threshold is crossed, indicate true immediately,
        // but require more distance to be crossed the other direction,
        // before resetting the indicator back to false.
        if (threshold.direction == thresholds::Direction::HIGH)
        {
            if (value >= threshold.value)
            {
                thresholdChanges.push_back(std::make_pair(threshold, true));
                ++cHiTrue;
            }
            else if (value < (threshold.value - sensor->hysteresisTrigger))
            {
                thresholdChanges.push_back(std::make_pair(threshold, false));
                ++cHiFalse;
            }
            else
            {
                ++cHiMidstate;
            }
        }
        else if (threshold.direction == thresholds::Direction::LOW)
        {
            if (value <= threshold.value)
            {
                thresholdChanges.push_back(std::make_pair(threshold, true));
                ++cLoTrue;
            }
            else if (value > (threshold.value + sensor->hysteresisTrigger))
            {
                thresholdChanges.push_back(std::make_pair(threshold, false));
                ++cLoFalse;
            }
            else
            {
                ++cLoMidstate;
            }
        }
        else
        {
            std::cerr << "Error determining threshold direction\n";
        }
    }

    if constexpr (DEBUG)
    {
        // Throttle debug output, so that it does not continuously spam
        ++cDebugThrottle;
        if (cDebugThrottle >= 1000)
        {
            cDebugThrottle = 0;
            std::cerr << "checkThresholds: High T=" << cHiTrue
                      << " F=" << cHiFalse << " M=" << cHiMidstate
                      << ", Low T=" << cLoTrue << " F=" << cLoFalse
                      << " M=" << cLoMidstate << "\n";
        }
    }

    return thresholdChanges;
}

bool checkThresholds(Sensor* sensor)
{
    bool status = true;
    std::vector<std::pair<Threshold, bool>> changes =
        checkThresholds(sensor, sensor->value);
    for (const auto& [threshold, asserted] : changes)
    {
        assertThresholds(sensor, threshold.level, threshold.direction,
                         asserted);
        if (threshold.level == thresholds::Level::CRITICAL && asserted)
        {
            status = false;
        }
    }

    return status;
}

void checkThresholdsPowerDelay(Sensor* sensor, ThresholdTimer& thresholdTimer)
{

    std::vector<std::pair<Threshold, bool>> changes =
        checkThresholds(sensor, sensor->value);
    for (const auto& [threshold, asserted] : changes)
    {
        if (asserted)
        {
            thresholdTimer.startTimer(threshold);
        }
        else
        {
            thresholdTimer.stopTimer(threshold);
            assertThresholds(sensor, threshold.level, threshold.direction,
                             false);
        }
    }
}

void assertThresholds(Sensor* sensor, thresholds::Level level,
                      thresholds::Direction direction, bool assert)
{
    std::string property;
    std::shared_ptr<sdbusplus::asio::dbus_interface> interface;
    if (level == thresholds::Level::WARNING &&
        direction == thresholds::Direction::HIGH)
    {
        property = "WarningAlarmHigh";
        interface = sensor->thresholdInterfaceWarning;
    }
    else if (level == thresholds::Level::WARNING &&
             direction == thresholds::Direction::LOW)
    {
        property = "WarningAlarmLow";
        interface = sensor->thresholdInterfaceWarning;
    }
    else if (level == thresholds::Level::CRITICAL &&
             direction == thresholds::Direction::HIGH)
    {
        property = "CriticalAlarmHigh";
        interface = sensor->thresholdInterfaceCritical;
    }
    else if (level == thresholds::Level::CRITICAL &&
             direction == thresholds::Direction::LOW)
    {
        property = "CriticalAlarmLow";
        interface = sensor->thresholdInterfaceCritical;
    }
    else
    {
        std::cerr << "Unknown threshold, level " << level << "direction "
                  << direction << "\n";
        return;
    }
    if (!interface)
    {
        std::cout << "trying to set uninitialized interface\n";
        return;
    }
    interface->set_property(property, assert);
}

std::optional<double> readFile(const std::string& thresholdFile,
                               const double& scaleFactor)
{
    std::string line;
    std::ifstream labelFile(thresholdFile);
    if (labelFile.good())
    {
        std::getline(labelFile, line);
        labelFile.close();

        try
        {
            return std::stod(line) / scaleFactor;
        }
        catch (const std::invalid_argument&)
        {
            return std::nullopt;
        }
    }
    return std::nullopt;
}

std::optional<std::tuple<std::string, std::string, std::string>>
    splitFileName(const std::filesystem::path& filePath)
{
    if (filePath.has_filename())
    {
        const auto fileName = filePath.filename().string();
        const std::regex rx(R"((\w+)(\d+)_(.*))");
        std::smatch mr;

        if (std::regex_search(fileName, mr, rx))
        {
            if (mr.size() == 4)
            {
                return std::make_optional(std::make_tuple(mr[1], mr[2], mr[3]));
            }
        }
    }
    return std::nullopt;
}

bool parseThresholdsFromAttr(
    std::vector<thresholds::Threshold>& thresholdVector,
    const std::string& inputPath, const double& scaleFactor,
    const double& offset)
{
    const boost::container::flat_map<
        std::string, std::vector<std::tuple<const char*, thresholds::Level,
                                            thresholds::Direction, double>>>
        map = {
            {"average",
             {
                 std::make_tuple("average_min", Level::WARNING, Direction::LOW,
                                 0.0),
                 std::make_tuple("average_max", Level::WARNING, Direction::HIGH,
                                 0.0),
             }},
            {"input",
             {
                 std::make_tuple("min", Level::WARNING, Direction::LOW, 0.0),
                 std::make_tuple("max", Level::WARNING, Direction::HIGH, 0.0),
                 std::make_tuple("lcrit", Level::CRITICAL, Direction::LOW, 0.0),
                 std::make_tuple("crit", Level::CRITICAL, Direction::HIGH,
                                 offset),
             }},
        };

    if (auto fileParts = splitFileName(inputPath))
    {
        auto [type, nr, item] = *fileParts;
        if (map.count(item) != 0)
        {
            for (const auto& t : map.at(item))
            {
                auto [suffix, level, direction, offset] = t;
                auto attrPath =
                    boost::replace_all_copy(inputPath, item, suffix);
                if (auto val = readFile(attrPath, scaleFactor))
                {
                    *val += offset;
                    if (DEBUG)
                    {
                        std::cout << "Threshold: " << attrPath << ": " << *val
                                  << "\n";
                    }
                    thresholdVector.emplace_back(level, direction, *val);
                }
            }
        }
    }
    return true;
}

bool hasCriticalInterface(
    const std::vector<thresholds::Threshold>& thresholdVector)
{
    for (auto& threshold : thresholdVector)
    {
        if (threshold.level == Level::CRITICAL)
        {
            return true;
        }
    }
    return false;
}

bool hasWarningInterface(
    const std::vector<thresholds::Threshold>& thresholdVector)
{
    for (auto& threshold : thresholdVector)
    {
        if (threshold.level == Level::WARNING)
        {
            return true;
        }
    }
    return false;
}
} // namespace thresholds