// /****************************************************************************************
//  *                                                                                       *
//  * OpenSpace                                                                             *
//  *                                                                                       *
//  * Copyright (c) 2014-2018                                                               *
//  *                                                                                       *
//  * Permission is hereby granted, free of charge, to any person obtaining a copy of this  *
//  * software and associated documentation files (the "Software"), to deal in the Software *
//  * without restriction, including without limitation the rights to use, copy, modify,    *
//  * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to    *
//  * permit persons to whom the Software is furnished to do so, subject to the following   *
//  * conditions:                                                                           *
//  *                                                                                       *
//  * The above copyright notice and this permission notice shall be included in all copies *
//  * or substantial portions of the Software.                                              *
//  *                                                                                       *
//  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,   *
//  * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A         *
//  * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT    *
//  * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF  *
//  * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE  *
//  * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                                         *
//  ****************************************************************************************/
// #include <fstream>
// #include <chrono>
// #include <vector>


// #include <modules/space/rendering/renderablesatellites.h>
// #include <modules/space/translation/keplertranslation.h>
// #include <modules/space/translation/TLEtranslation.h>
// #include <modules/space/spacemodule.h>


// #include <modules/base/basemodule.h>

// #include <openspace/engine/openspaceengine.h>
// #include <openspace/rendering/renderengine.h>
// #include <openspace/engine/globals.h>
// #include <openspace/documentation/verifier.h>
// #include <openspace/util/time.h>
// #include <openspace/util/updatestructures.h>

// #include <ghoul/filesystem/filesystem.h>
// #include <ghoul/filesystem/file.h>
// #include <ghoul/misc/csvreader.h>
// #include <ghoul/opengl/programobject.h>


// #include <fstream>


// // Todo:
// // Parse epoch correctly
// // read distances using correct unit
// // ...

// namespace {
//     constexpr const char* ProgramName = "KeplerTrails";
//     constexpr const char* KeyFile = "File";
//     constexpr const char* KeyLineNum = "LineNumber";

    
//     static const openspace::properties::Property::PropertyInfo PathInfo = {
//         "Path",
//         "Path",
//         "The file path to the CSV file to read"
//     };
    
//     static const openspace::properties::Property::PropertyInfo SegmentsInfo = {
//         "Segments",
//         "Segments",
//         "The number of segments to use for each orbit ellipse"
//     };
    
//     static const openspace::properties::Property::PropertyInfo EccentricityColumnInfo = {
//         "EccentricityColumn",
//         "EccentricityColumn",
//         "The header of the column where the eccentricity is stored"
//     };
    
//     static const openspace::properties::Property::PropertyInfo SemiMajorAxisColumnInfo = {
//         "SemiMajorAxisColumn",
//         "SemiMajorAxisColumn",
//         "The header of the column where the semi-major axis is stored"
//     };
    
//     static const openspace::properties::Property::PropertyInfo SemiMajorAxisUnitInfo = {
//         "SemiMajorAxisUnit",
//         "SemiMajorAxisUnit",
//         "The unit of the semi major axis. For example: If specified in km, set this to 1000."
//     };
    
//     static const openspace::properties::Property::PropertyInfo InclinationColumnInfo = {
//         "InclinationColumn",
//         "InclinationColumn",
//         "The header of the column where the inclination is stored"
//     };
    
//     static const openspace::properties::Property::PropertyInfo AscendingNodeColumnInfo = {
//         "AscendingNodeColumn",
//         "AscendingNodeColumn",
//         "The header of the column where the ascending node is stored"
//     };
    
//     static const openspace::properties::Property::PropertyInfo ArgumentOfPeriapsisColumnInfo = {
//         "ArgumentOfPeriapsisColumn",
//         "ArgumentOfPeriapsisColumn",
//         "The header of the column where the argument of periapsis is stored"
//     };
    
//     static const openspace::properties::Property::PropertyInfo MeanAnomalyAtEpochColumnInfo = {
//         "MeanAnomalyAtEpochColumn",
//         "MeanAnomalyAtEpochColumn",
//         "The header of the column where the mean anomaly at epoch is stored"
//     };
    
//     static const openspace::properties::Property::PropertyInfo EpochColumnInfo = {
//         "EpochColumn",
//         "EpochColumn",
//         "The header of the column where the epoch is stored"
//     };
// }

// namespace openspace {
 
documentation::Documentation RenderableSatellites::Documentation() {
    using namespace documentation;
    return {
        "Renderable Kepler Orbits",
        "space_renderable_kepler_orbits",
        {
            {
                SegmentsInfo.identifier,
                new DoubleVerifier,
                Optional::No,
                SegmentsInfo.description
            },
            {
                PathInfo.identifier,
                new StringVerifier,
                Optional::No,
                PathInfo.description
            },
            {
                EccentricityColumnInfo.identifier,
                new StringVerifier,
                Optional::No,
                EccentricityColumnInfo.description
            },
            {
                SemiMajorAxisColumnInfo.identifier,
                new StringVerifier,
                Optional::No,
                SemiMajorAxisColumnInfo.description
            },
            {
                SemiMajorAxisUnitInfo.identifier,
                new DoubleVerifier,
                Optional::No,
                SemiMajorAxisUnitInfo.description
            },
            {
                InclinationColumnInfo.identifier,
                new StringVerifier,
                Optional::No,
                InclinationColumnInfo.description
            },
            {
                AscendingNodeColumnInfo.identifier,
                new StringVerifier,
                Optional::No,
                AscendingNodeColumnInfo.description
            },
            {
                ArgumentOfPeriapsisColumnInfo.identifier,
                new StringVerifier,
                Optional::No,
                ArgumentOfPeriapsisColumnInfo.description
            },
            {
                MeanAnomalyAtEpochColumnInfo.identifier,
                new StringVerifier,
                Optional::No,
                MeanAnomalyAtEpochColumnInfo.description
            },
            {
                EpochColumnInfo.identifier,
                new StringVerifier,
                Optional::No,
                EpochColumnInfo.description
            }
        }
    };
}
    
RenderableSatellites::RenderableSatellites(const ghoul::Dictionary& dictionary)
    : Renderable(dictionary)
    , _path(PathInfo)
    , _nSegments(SegmentsInfo)
    , _eccentricityColumnName(EccentricityColumnInfo)
    , _semiMajorAxisColumnName(SemiMajorAxisColumnInfo)
    , _semiMajorAxisUnit(SemiMajorAxisUnitInfo)
    , _inclinationColumnName(InclinationColumnInfo)
    , _ascendingNodeColumnName(AscendingNodeColumnInfo)
    , _argumentOfPeriapsisColumnName(ArgumentOfPeriapsisColumnInfo)
    , _meanAnomalyAtEpochColumnName(MeanAnomalyAtEpochColumnInfo)
    , _epochColumnName(EpochColumnInfo)
{
    documentation::testSpecificationAndThrow(
         Documentation(),
         dictionary,
         "RenderableSatellites"
         );

    _nSegments =
        static_cast<int>(dictionary.value<double>(SegmentsInfo.identifier));
    _path =
        dictionary.value<std::string>(PathInfo.identifier);
    _eccentricityColumnName =
        dictionary.value<std::string>(EccentricityColumnInfo.identifier);
    _semiMajorAxisColumnName =
        dictionary.value<std::string>(SemiMajorAxisColumnInfo.identifier);
    _inclinationColumnName =
        dictionary.value<std::string>(InclinationColumnInfo.identifier);
    _ascendingNodeColumnName =
        dictionary.value<std::string>(AscendingNodeColumnInfo.identifier);
    _argumentOfPeriapsisColumnName =
        dictionary.value<std::string>(ArgumentOfPeriapsisColumnInfo.identifier);
    _meanAnomalyAtEpochColumnName =
        dictionary.value<std::string>(MeanAnomalyAtEpochColumnInfo.identifier);
    _epochColumnName =
        dictionary.value<std::string>(EpochColumnInfo.identifier);
    _semiMajorAxisUnit =
        dictionary.value<double>(SemiMajorAxisUnitInfo.identifier);
    
    addPropertySubOwner(_appearance);
    addProperty(_path);
    addProperty(_nSegments);
    addProperty(_semiMajorAxisUnit);

/*
* test
*/

    const std::string& file = dictionary.value<std::string>(KeyFile);
    readTLEFile(file);

}
    // The list of leap years only goes until 2056 as we need to touch this file then
    // again anyway ;)
    const std::vector<int> LeapYears = {
        1956, 1960, 1964, 1968, 1972, 1976, 1980, 1984, 1988, 1992, 1996,
        2000, 2004, 2008, 2012, 2016, 2020, 2024, 2028, 2032, 2036, 2040,
        2044, 2048, 2052, 2056
    };

    // Count the number of full days since the beginning of 2000 to the beginning of
    // the parameter 'year'
    int countDays(int year) {
        // Find the position of the current year in the vector, the difference
        // between its position and the position of 2000 (for J2000) gives the
        // number of leap years
        constexpr const int Epoch = 2000;
        constexpr const int DaysRegularYear = 365;
        constexpr const int DaysLeapYear = 366;

        if (year == Epoch) {
            return 0;
        }

        // Get the position of the most recent leap year
        const auto lb = std::lower_bound(LeapYears.begin(), LeapYears.end(), year);

        // Get the position of the epoch
        const auto y2000 = std::find(LeapYears.begin(), LeapYears.end(), Epoch);

        // The distance between the two iterators gives us the number of leap years
        const int nLeapYears = static_cast<int>(std::abs(std::distance(y2000, lb)));

        const int nYears = std::abs(year - Epoch);
        const int nRegularYears = nYears - nLeapYears;

        // Get the total number of days as the sum of leap years + non leap years
        const int result = nRegularYears * DaysRegularYear + nLeapYears * DaysLeapYear;
        return result;
    }

    // Returns the number of leap seconds that lie between the {year, dayOfYear}
    // time point and { 2000, 1 }
    int countLeapSeconds(int year, int dayOfYear) {
        // Find the position of the current year in the vector; its position in
        // the vector gives the number of leap seconds
        struct LeapSecond {
            int year;
            int dayOfYear;
            bool operator<(const LeapSecond& rhs) const {
                return std::tie(year, dayOfYear) < std::tie(rhs.year, rhs.dayOfYear);
            }
        };

        const LeapSecond Epoch = { 2000, 1 };

        // List taken from: https://www.ietf.org/timezones/data/leap-seconds.list
        static const std::vector<LeapSecond> LeapSeconds = {
            { 1972,   1 },
            { 1972, 183 },
            { 1973,   1 },
            { 1974,   1 },
            { 1975,   1 },
            { 1976,   1 },
            { 1977,   1 },
            { 1978,   1 },
            { 1979,   1 },
            { 1980,   1 },
            { 1981, 182 },
            { 1982, 182 },
            { 1983, 182 },
            { 1985, 182 },
            { 1988,   1 },
            { 1990,   1 },
            { 1991,   1 },
            { 1992, 183 },
            { 1993, 182 },
            { 1994, 182 },
            { 1996,   1 },
            { 1997, 182 },
            { 1999,   1 },
            { 2006,   1 },
            { 2009,   1 },
            { 2012, 183 },
            { 2015, 182 },
            { 2017,   1 }
        };

        // Get the position of the last leap second before the desired date
        LeapSecond date { year, dayOfYear };
        const auto it = std::lower_bound(LeapSeconds.begin(), LeapSeconds.end(), date);

        // Get the position of the Epoch
        const auto y2000 = std::lower_bound(
            LeapSeconds.begin(),
            LeapSeconds.end(),
            Epoch
        );

        // The distance between the two iterators gives us the number of leap years
        const int nLeapSeconds = static_cast<int>(std::abs(std::distance(y2000, it)));
        return nLeapSeconds;
    }

    double calculateSemiMajorAxis(double meanMotion) {
        constexpr const double GravitationalConstant = 6.6740831e-11;
        constexpr const double MassEarth = 5.9721986e24;
        constexpr const double muEarth = GravitationalConstant * MassEarth;

        // Use Kepler's 3rd law to calculate semimajor axis
        // a^3 / P^2 = mu / (2pi)^2
        // <=> a = ((mu * P^2) / (2pi^2))^(1/3)
        // with a = semimajor axis
        // P = period in seconds
        // mu = G*M_earth
        double period = std::chrono::seconds(std::chrono::hours(24)).count() / meanMotion;

        const double pisq = glm::pi<double>() * glm::pi<double>();
        double semiMajorAxis = pow((muEarth * period*period) / (4 * pisq), 1.0 / 3.0);

        // We need the semi major axis in km instead of m
        return semiMajorAxis / 1000.0;
    }

double epochFromSubstring(const std::string& epochString) {
        // The epochString is in the form:
        // YYDDD.DDDDDDDD
        // With YY being the last two years of the launch epoch, the first DDD the day
        // of the year and the remaning a fractional part of the day

        // The main overview of this function:
        // 1. Reconstruct the full year from the YY part
        // 2. Calculate the number of seconds since the beginning of the year
        // 2.a Get the number of full days since the beginning of the year
        // 2.b If the year is a leap year, modify the number of days
        // 3. Convert the number of days to a number of seconds
        // 4. Get the number of leap seconds since January 1st, 2000 and remove them
        // 5. Adjust for the fact the epoch starts on 1st Januaray at 12:00:00, not
        // midnight

        // According to https://celestrak.com/columns/v04n03/
        // Apparently, US Space Command sees no need to change the two-line element
        // set format yet since no artificial earth satellites existed prior to 1957.
        // By their reasoning, two-digit years from 57-99 correspond to 1957-1999 and
        // those from 00-56 correspond to 2000-2056. We'll see each other again in 2057!

        // 1. Get the full year
        std::string yearPrefix = [y = epochString.substr(0, 2)](){
            int year = std::atoi(y.c_str());
            return year >= 57 ? "19" : "20";
        }();
        const int year = std::atoi((yearPrefix + epochString.substr(0, 2)).c_str());
        const int daysSince2000 = countDays(year);

        // 2.
        // 2.a
        double daysInYear = std::atof(epochString.substr(2).c_str());

        // 2.b
        const bool isInLeapYear = std::find(
            LeapYears.begin(),
            LeapYears.end(),
            year
        ) != LeapYears.end();
        if (isInLeapYear && daysInYear >= 60) {
            // We are in a leap year, so we have an effective day more if we are
            // beyond the end of february (= 31+29 days)
            --daysInYear;
        }

        // 3
        using namespace std::chrono;
        const int SecondsPerDay = static_cast<int>(seconds(hours(24)).count());
        //Need to subtract 1 from daysInYear since it is not a zero-based count
        const double nSecondsSince2000 = (daysSince2000 + daysInYear - 1) * SecondsPerDay;

        // 4
        // We need to remove additionbal leap seconds past 2000 and add them prior to
        // 2000 to sync up the time zones
        const double nLeapSecondsOffset = -countLeapSeconds(
            year,
            static_cast<int>(std::floor(daysInYear))
        );

        // 5
        const double nSecondsEpochOffset = static_cast<double>(
            seconds(hours(12)).count()
        );

        // Combine all of the values
        const double epoch = nSecondsSince2000 + nLeapSecondsOffset - nSecondsEpochOffset;
        return epoch;
    }
    
void RenderableSatellites::readTLEFile(const std::string& filename){
    ghoul_assert(FileSys.fileExists(filename), "The filename must exist");

    std::ifstream file;
    file.exceptions(std::ofstream::failbit | std::ofstream::badbit);
    file.open(filename);

    // All of the Kepler element information
    struct {
        double inclination = 0.0;
        double semiMajorAxis = 0.0;
        double ascendingNode = 0.0;
        double eccentricity = 0.0;
        double argumentOfPeriapsis = 0.0;
        double meanAnomaly = 0.0;
        double meanMotion = 0.0;
        double epoch = 0.0;
    } keplerElements;

    std::string line;
    // Loop through and throw out lines until getting to the linNum of interest
    for (int i = 1; i < lineNum; ++i) {
        std::getline(file, line);
    }
    std::getline(file, line); // Throw out the TLE title line (1st)

    std::getline(file, line); // Get line 1 of TLE format
    if (line[0] == '1') {
        // First line
        // Field Columns   Content
        //     1   01-01   Line number
        //     2   03-07   Satellite number
        //     3   08-08   Classification (U = Unclassified)
        //     4   10-11   International Designator (Last two digits of launch year)
        //     5   12-14   International Designator (Launch number of the year)
        //     6   15-17   International Designator(piece of the launch)    A
        //     7   19-20   Epoch Year(last two digits of year)
        //     8   21-32   Epoch(day of the year and fractional portion of the day)
        //     9   34-43   First Time Derivative of the Mean Motion divided by two
        //    10   45-52   Second Time Derivative of Mean Motion divided by six
        //    11   54-61   BSTAR drag term(decimal point assumed)[10] - 11606 - 4
        //    12   63-63   The "Ephemeris type"
        //    13   65-68   Element set  number.Incremented when a new TLE is generated
        //    14   69-69   Checksum (modulo 10)
        keplerElements.epoch = epochFromSubstring(line.substr(18, 14));
    } else {
        throw ghoul::RuntimeError(fmt::format(
            "File {} @ line {} does not have '1' header", filename, lineNum + 1
        ));
    }

    std::getline(file, line); // Get line 2 of TLE format
     if (line[0] == '2') {
        // Second line
        // Field    Columns   Content
        //     1      01-01   Line number
        //     2      03-07   Satellite number
        //     3      09-16   Inclination (degrees)
        //     4      18-25   Right ascension of the ascending node (degrees)
        //     5      27-33   Eccentricity (decimal point assumed)
        //     6      35-42   Argument of perigee (degrees)
        //     7      44-51   Mean Anomaly (degrees)
        //     8      53-63   Mean Motion (revolutions per day)
        //     9      64-68   Revolution number at epoch (revolutions)
        //    10      69-69   Checksum (modulo 10)

        std::stringstream stream;
        stream.exceptions(std::ios::failbit);

        // Get inclination
        stream.str(line.substr(8, 8));
        stream >> keplerElements.inclination;
        stream.clear();

        // Get Right ascension of the ascending node
        stream.str(line.substr(17, 8));
        stream >> keplerElements.ascendingNode;
        stream.clear();

        // Get Eccentricity
        stream.str("0." + line.substr(26, 7));
        stream >> keplerElements.eccentricity;
        stream.clear();

        // Get argument of periapsis
        stream.str(line.substr(34, 8));
        stream >> keplerElements.argumentOfPeriapsis;
        stream.clear();

        // Get mean anomaly
        stream.str(line.substr(43, 8));
        stream >> keplerElements.meanAnomaly;
        stream.clear();

        // Get mean motion
        stream.str(line.substr(52, 11));
        stream >> keplerElements.meanMotion;
    } else {
        throw ghoul::RuntimeError(fmt::format(
            "File {} @ line {} does not have '2' header", filename, lineNum + 2
        ));
    }
    file.close();

    // Calculate the semi major axis based on the mean motion using kepler's laws
    keplerElements.semiMajorAxis = calculateSemiMajorAxis(keplerElements.meanMotion);

    // Converting the mean motion (revolutions per day) to period (seconds per revolution)
    using namespace std::chrono;
    double period = seconds(hours(24)).count() / keplerElements.meanMotion;      
    

    /*
    KeplerTranslation setKeplerElements(
        keplerElements.eccentricity,
        keplerElements.semiMajorAxis,
        keplerElements.inclination,
        keplerElements.ascendingNode,
        keplerElements.argumentOfPeriapsis,
        keplerElements.meanAnomaly,
        period,
        keplerElements.epoch
    );
    */
}

/*
* !test
*/
RenderableSatellites::~RenderableSatellites() {

}
    
void RenderableSatellites::initialize() {
    readFromCsvFile();
    updateBuffers();

    _path.onChange([this]() {
        readFromCsvFile();
        updateBuffers();
    });
    
    _semiMajorAxisUnit.onChange([this]() {
        readFromCsvFile();
        updateBuffers();
    });

    _nSegments.onChange([this]() {
        updateBuffers();
    });
}

void RenderableSatellites::deinitialize() {
    
}
 
void RenderableSatellites::initializeGL() {
    glGenVertexArrays(1, &_vertexArray);
    glGenBuffers(1, &_vertexBuffer);
    glGenBuffers(1, &_indexBuffer);
    
    _programObject = SpaceModule::ProgramObjectManager.request(
       ProgramName,
       []() -> std::unique_ptr<ghoul::opengl::ProgramObject> {
           return global::renderEngine.buildRenderProgram(
               ProgramName,
               absPath("${MODULE_SPACE}/shaders/RenderableKeplerOrbits_vs.glsl"),
               absPath("${MODULE_SPACE}/shaders/RenderableKeplerOrbits_fs.glsl")
           );
       }
   );
    
    _uniformCache.opacity = _programObject->uniformLocation("opacity");
    _uniformCache.modelView = _programObject->uniformLocation("modelViewTransform");
    _uniformCache.projection = _programObject->uniformLocation("projectionTransform");
    _uniformCache.color = _programObject->uniformLocation("color");
    _uniformCache.useLineFade = _programObject->uniformLocation("useLineFade");
    _uniformCache.lineFade = _programObject->uniformLocation("lineFade");
    
    setRenderBin(Renderable::RenderBin::Overlay);
}
    
void RenderableSatellites::deinitializeGL() {
    SpaceModule::ProgramObjectManager.release(ProgramName);
    
    glDeleteBuffers(1, &_vertexBuffer);
    glDeleteBuffers(1, &_indexBuffer);
    glDeleteVertexArrays(1, &_vertexArray);
}

    
bool RenderableSatellites::isReady() const {
    return true;
}

void RenderableSatellites::update(const UpdateData&) {}
    
void RenderableSatellites::render(const RenderData& data, RendererTasks&) {
    _programObject->activate();
    _programObject->setUniform(_uniformCache.opacity, _opacity);
    
    glm::dmat4 modelTransform =
        glm::translate(glm::dmat4(1.0), data.modelTransform.translation) *
        glm::dmat4(data.modelTransform.rotation) *
        glm::scale(glm::dmat4(1.0), glm::dvec3(data.modelTransform.scale));

    _programObject->setUniform(
        _uniformCache.modelView,
        data.camera.combinedViewMatrix() * modelTransform
    );

    _programObject->setUniform(_uniformCache.projection, data.camera.projectionMatrix());
    _programObject->setUniform(_uniformCache.color, _appearance.lineColor);
    //_programObject->setUniform(_uniformCache.useLineFade, _appearance.useLineFade);

    /*if (_appearance.useLineFade) {
        _programObject->setUniform(_uniformCache.lineFade, _appearance.lineFade);
    }*/

    glDepthMask(false);
    //glBlendFunc(GL_SRC_ALPHA, GL_ONE);

    glBindVertexArray(_vertexArray);
    glDrawElements(GL_LINES,
                   static_cast<unsigned int>(_indexBufferData.size()),
                   GL_UNSIGNED_INT,
                   0);
    glBindVertexArray(0);
    _programObject->deactivate();
}

void RenderableSatellites::updateBuffers() {
    const size_t nVerticesPerOrbit = _nSegments + 1;
    _vertexBufferData.resize(_orbits.size() * nVerticesPerOrbit);
    _indexBufferData.resize(_orbits.size() * _nSegments * 2);
    
    size_t orbitIndex = 0;
    size_t elementIndex = 0;
    for (const auto& orbit : _orbits) { // _orbits blir TLEData
        // KeplerTranslation setKeplerElements(TLEData);
        KeplerTranslation keplerTranslation(orbit); // Existerar inte längre
        const double period = orbit.period();
        for (size_t i = 0; i <= _nSegments; ++i) {
            size_t index = orbitIndex * nVerticesPerOrbit + i;

            double timeOffset = period *
                static_cast<float>(i) / static_cast<float>(_nSegments);
            glm::vec3 position =
                keplerTranslation.position(Time(orbit.epoch + timeOffset));
                //keplerTranslation.position(orbit.epoch + timeOffset);


            _vertexBufferData[index].x = position.x;
            _vertexBufferData[index].y = position.y;
            _vertexBufferData[index].z = position.z;
            _vertexBufferData[index].time = timeOffset;
            if (i > 0) {
                _indexBufferData[elementIndex++] = static_cast<unsigned int>(index) - 1;
                _indexBufferData[elementIndex++] = static_cast<unsigned int>(index);
            }
        }
        ++orbitIndex;
    }
    
    glBindVertexArray(_vertexArray);
    
    glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer);
    glBufferData(GL_ARRAY_BUFFER,
                 _vertexBufferData.size() * sizeof(TrailVBOLayout),
                 _vertexBufferData.data(),
                 GL_STATIC_DRAW
                 );
    

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _indexBuffer);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER,
                 _indexBufferData.size() * sizeof(int),
                 _indexBufferData.data(),
                 GL_STATIC_DRAW
                 );
    
    glBindVertexArray(0);
}

void RenderableSatellites::readFromCsvFile() {
    std::vector<std::string> columns = {
        _eccentricityColumnName,
        _semiMajorAxisColumnName,
        _inclinationColumnName,
        _ascendingNodeColumnName,
        _argumentOfPeriapsisColumnName,
        _meanAnomalyAtEpochColumnName,
        _epochColumnName,
    };
    
    std::vector<std::vector<std::string>> data =
        ghoul::loadCSVFile(_path, columns, false);

    _orbits.resize(data.size());
    
    size_t i = 0;
    for (const std::vector<std::string>& line : data) {
        _orbits[i++] = KeplerTranslation::KeplerOrbit{
            std::stof(line[0]),
            _semiMajorAxisUnit * std::stof(line[1]) / 1000.0,
            std::stof(line[2]),
            std::stof(line[3]),
            std::stof(line[4]),
            std::stof(line[5]),
            std::stof(line[6])
        };
    }
}
    
}