/* ============================================================
 *
 * This file is a part of digiKam project
 * https://www.digikam.org
 *
 * Date        : 2006-09-19
 * Description : GPS data file parser.
 *               (GPX format https://www.topografix.com/gpx.asp).
 *
 * SPDX-FileCopyrightText: 2006-2026 by Gilles Caulier <caulier dot gilles at gmail dot com>
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * ============================================================ */

#include "geodataparser.h"
#include "geodataparser_time.h"

// C++ includes

#include <cmath>
#include <cstdlib>

// Qt includes

#include <QDomDocument>
#include <QFile>
#include <QString>
#include <QIODevice>

// Local includes

#include "digikam_debug.h"
#include "digikam_globals.h"

namespace DigikamGenericGeolocationEditPlugin
{

GeoDataParser::GeoDataParser()
{
    clear();
}

void GeoDataParser::clear()
{
    m_GeoDataMap.clear();
}

int GeoDataParser::numPoints() const
{
    return m_GeoDataMap.count();
}

bool GeoDataParser::matchDate(const QDateTime& photoDateTime, int maxGapTime, int secondsOffset,
                              bool offsetContainsTimeZone,
                              bool interpolate, int interpolationDstTime,
                              GeoDataContainer* const gpsData)
{
    // GPS device are sync in time by satellite using GMT time.

    QDateTime cameraGMTDateTime = photoDateTime.addSecs(secondsOffset*(-1));

    if (offsetContainsTimeZone)
    {
        cameraGMTDateTime = Digikam::asDateTimeUTC(cameraGMTDateTime);
    }

    qCDebug(DIGIKAM_DPLUGIN_GENERIC_LOG) << "    photoDateTime: " << photoDateTime << photoDateTime.timeSpec();
    qCDebug(DIGIKAM_DPLUGIN_GENERIC_LOG) << "cameraGMTDateTime: " << cameraGMTDateTime << cameraGMTDateTime.timeSpec();

    // We are trying to find the right date in the GPS points list.

    bool findItem = false;
    int nbSecItem = maxGapTime;
    int nbSecs;

    for (GeoDataMap::ConstIterator it = m_GeoDataMap.constBegin() ; it != m_GeoDataMap.constEnd() ; ++it )
    {
        // Here we check a possible accuracy in seconds between the
        // Camera GMT time and the GPS device GMT time.

        nbSecs = qAbs(cameraGMTDateTime.secsTo( it.key() ));
/*
        qCDebug(DIGIKAM_DPLUGIN_GENERIC_LOG) << it.key() << cameraGMTDateTime << nbSecs;
        qCDebug(DIGIKAM_DPLUGIN_GENERIC_LOG) << it.key().timeSpec() << cameraGMTDateTime.timeSpec() << nbSecs;
*/
        // We're trying to find the minimal accuracy.

        if ((nbSecs < maxGapTime) && (nbSecs < nbSecItem))
        {
            if (gpsData)
            {
                *gpsData = m_GeoDataMap[it.key()];
            }

            findItem  = true;
            nbSecItem = nbSecs;
        }
    }

    if (findItem)
    {
        return true;
    }

    // If we cannot find it, we will trying to interpolate the GPS point.

    if (interpolate)
    {
        // The interpolate GPS point will be separate by at the maximum of 'interpolationDstTime'
        // seconds before and after the next and previous real GPS point found.

        QDateTime prevDateTime = findPrevDate(cameraGMTDateTime, interpolationDstTime);
        QDateTime nextDateTime = findNextDate(cameraGMTDateTime, interpolationDstTime);

        if (!nextDateTime.isNull() && !prevDateTime.isNull())
        {
            GeoDataContainer prevGPSPoint = m_GeoDataMap[prevDateTime];
            GeoDataContainer nextGPSPoint = m_GeoDataMap[nextDateTime];

            double alt1                   = prevGPSPoint.altitude();
            double lon1                   = prevGPSPoint.longitude();
            double lat1                   = prevGPSPoint.latitude();
            uint   t1                     = prevDateTime.toSecsSinceEpoch();
            double alt2                   = nextGPSPoint.altitude();
            double lon2                   = nextGPSPoint.longitude();
            double lat2                   = nextGPSPoint.latitude();
            uint   t2                     = nextDateTime.toSecsSinceEpoch();
            uint   tCor                   = cameraGMTDateTime.toSecsSinceEpoch();

            if ((tCor - t1) != 0)
            {
                if (gpsData)
                {
                    gpsData->setAltitude(alt1  + (alt2-alt1) * (tCor-t1)/(t2-t1));
                    gpsData->setLatitude(lat1  + (lat2-lat1) * (tCor-t1)/(t2-t1));
                    gpsData->setLongitude(lon1 + (lon2-lon1) * (tCor-t1)/(t2-t1));
                    gpsData->setInterpolated(true);
                }

                return true;
            }
        }
    }

    return false;
}

QDateTime GeoDataParser::findNextDate(const QDateTime& dateTime, int secs)
{
    // We will find the item in GPS data list where the time is
    // at the maximum bigger than 'secs' mn of the value to match.

    QDateTime itemFound = dateTime.addSecs(secs);
    bool found          = false;

    for (GeoDataMap::ConstIterator it = m_GeoDataMap.constBegin() ; it != m_GeoDataMap.constEnd() ; ++it)
    {
        if (it.key() > dateTime)
        {
            if (it.key() < itemFound)
            {
                itemFound = it.key();
                found = true;
            }
        }
    }

    if (found)
    {
        return itemFound;
    }

    return QDateTime();
}

QDateTime GeoDataParser::findPrevDate(const QDateTime& dateTime, int secs)
{
    // We will find the item in GPS data list where the time is
    // at the maximum smaller than 'secs' mn of the value to match.

    QDateTime itemFound = dateTime.addSecs((-1)*secs);
    bool found          = false;

    for (GeoDataMap::ConstIterator it = m_GeoDataMap.constBegin() ; it != m_GeoDataMap.constEnd() ; ++it)
    {
        if (it.key() < dateTime)
        {
            if (it.key() > itemFound)
            {
                itemFound = it.key();
                found     = true;
            }
        }
    }

    if (found)
    {
        return itemFound;
    }

    return QDateTime();
}

bool GeoDataParser::loadGPXFile(const QUrl& url)
{
    QFile gpxfile(url.toLocalFile());

    if (!gpxfile.open(QIODevice::ReadOnly))
    {
        return false;
    }

    QDomDocument gpxDoc(QLatin1String("gpx"));

    if (!gpxDoc.setContent(&gpxfile))
    {
        gpxfile.close();

        return false;
    }

    QDomElement gpxDocElem = gpxDoc.documentElement();

    if (gpxDocElem.tagName() != QLatin1String("gpx"))
    {
        gpxfile.close();

        return false;
    }

    for (QDomNode nTrk = gpxDocElem.firstChild(); !nTrk.isNull(); nTrk = nTrk.nextSibling())
    {
        QDomElement trkElem = nTrk.toElement();

        if (trkElem.isNull())
        {
            continue;
        }

        if (trkElem.tagName() != QLatin1String("trk"))
        {
            continue;
        }

        for (QDomNode nTrkseg = trkElem.firstChild() ; !nTrkseg.isNull() ; nTrkseg = nTrkseg.nextSibling())
        {
            QDomElement trksegElem = nTrkseg.toElement();

            if (trksegElem.isNull())
            {
                continue;
            }

            if (trksegElem.tagName() != QLatin1String("trkseg"))
            {
                continue;
            }

            for (QDomNode nTrkpt = trksegElem.firstChild() ; !nTrkpt.isNull() ; nTrkpt = nTrkpt.nextSibling())
            {
                QDomElement trkptElem = nTrkpt.toElement();

                if (trkptElem.isNull())
                {
                    continue;
                }

                if (trkptElem.tagName() != QLatin1String("trkpt"))
                {
                    continue;
                }

                QDateTime ptDateTime;
                double    ptAltitude  = 0.0;
                double    ptLatitude  = 0.0;
                double    ptLongitude = 0.0;

                // Get GPS position. If not available continue to next point.

                QString lat = trkptElem.attribute(QLatin1String("lat"));
                QString lon = trkptElem.attribute(QLatin1String("lon"));

                if (lat.isEmpty() || lon.isEmpty())
                {
                    continue;
                }

                ptLatitude  = lat.toDouble();
                ptLongitude = lon.toDouble();

                // Get metadata of track point (altitude and time stamp)

                for (QDomNode nTrkptMeta = trkptElem.firstChild() ; !nTrkptMeta.isNull() ; nTrkptMeta = nTrkptMeta.nextSibling())
                {
                    QDomElement trkptMetaElem = nTrkptMeta.toElement();

                    if (trkptMetaElem.isNull())
                    {
                        continue;
                    }

                    if (trkptMetaElem.tagName() == QLatin1String("time"))
                    {
                        // Get GPS point time stamp. If not available continue to next point.

                        const QString time = trkptMetaElem.text();

                        if (time.isEmpty())
                        {
                            continue;
                        }

                        ptDateTime = GeoDataParserParseTime(time);
                    }

                    if (trkptMetaElem.tagName() == QLatin1String("ele"))
                    {
                        // Get GPS point altitude. If not available continue to next point.

                        QString ele = trkptMetaElem.text();

                        if (!ele.isEmpty())
                        {
                            ptAltitude  = ele.toDouble();
                        }
                    }
                }

                if (ptDateTime.isNull())
                {
                    continue;
                }

                GeoDataContainer gpsData(ptAltitude, ptLatitude, ptLongitude, false);
                m_GeoDataMap.insert( ptDateTime, gpsData );
            }
        }
    }
/*
    qCDebug(DIGIKAM_DPLUGIN_GENERIC_LOG) << "GPX File " << url.fileName()
                                         << " parsed with " << numPoints()
                                         << " points extracted" ;
*/
    gpxfile.close();

    return true;
}

} // namespace DigikamGenericGeolocationEditPlugin
