/* ============================================================
 *
 * This file is a part of digiKam project
 * https://www.digikam.org
 *
 * Date        : 2023-05-15
 * Description : geolocation engine based on Marble.
 *               (c) 2007-2022 Marble Team
 *               https://invent.kde.org/education/marble/-/raw/master/data/credits_authors.html
 *
 * SPDX-FileCopyrightText: 2023-2026 by Gilles Caulier <caulier dot gilles at gmail dot com>
 *
 * SPDX-License-Identifier: LGPL-2.1-or-later
 *
 * ============================================================ */

#include "TileLoader.h"

// Qt includes

#include <QDateTime>
#include <QFileInfo>
#include <QMetaType>
#include <QImage>
#include <QUrl>

// Local includes

#include "GeoSceneTextureTileDataset.h"
#include "GeoSceneTileDataset.h"
#include "GeoSceneTypes.h"
#include "GeoSceneVectorTileDataset.h"
#include "GeoDataDocument.h"
#include "HttpDownloadManager.h"
#include "MarbleDirs.h"
#include "TileId.h"
#include "TileLoaderHelper.h"
#include "ParseRunnerPlugin.h"
#include "ParsingRunner.h"
#include "digikam_debug.h"

Q_DECLARE_METATYPE(Marble::DownloadUsage)

namespace Marble
{

TileLoader::TileLoader(HttpDownloadManager* const downloadManager, const PluginManager* pluginManager) :
    m_pluginManager(pluginManager)
{
    qRegisterMetaType<DownloadUsage>("DownloadUsage");

    connect(this, SIGNAL(downloadTile(QUrl,QString,QString,DownloadUsage)),
            downloadManager, SLOT(addJob(QUrl,QString,QString,DownloadUsage)));

    connect(downloadManager, SIGNAL(downloadComplete(QString,QString)),
            SLOT(updateTile(QString,QString)));

    connect(downloadManager, SIGNAL(downloadComplete(QByteArray,QString)),
            SLOT(updateTile(QByteArray,QString)));
}

TileLoader::~TileLoader()
{
    // nothing to do
}

// If the tile image file is locally available:
//     - if not expired: create ImageTile, set state to "uptodate", return it => done
//     - if expired: create TextureTile, state is set to Expired by default, trigger dl,
QImage TileLoader::loadTileImage(GeoSceneTextureTileDataset const* textureLayer, TileId const& tileId, DownloadUsage const usage)
{
    QString const fileName = tileFileName(textureLayer, tileId);
    TileStatus status      = tileStatus(textureLayer, tileId);

    if (status != Missing)
    {
        // check if an update should be triggered

        if (status == Available)
        {
            qCDebug(DIGIKAM_GEOENGINE_LOG) << Q_FUNC_INFO << tileId << "StateUptodate";
        }

        else
        {
            Q_ASSERT(status == Expired);

            qCDebug(DIGIKAM_GEOENGINE_LOG) << Q_FUNC_INFO << tileId << "StateExpired";
            triggerDownload(textureLayer, tileId, usage);
        }

        QImage const image(fileName);

        if (!image.isNull())
        {
            // file is there, so create and return a tile object in any case

            return image;
        }
    }

    // tile was not locally available => trigger download and look for tiles in other levels
    // for scaling

    QImage replacementTile = scaledLowerLevelTile(textureLayer, tileId);

    Q_ASSERT(!replacementTile.isNull());

    triggerDownload(textureLayer, tileId, usage);

    return replacementTile;
}

GeoDataDocument* TileLoader::loadTileVectorData(GeoSceneVectorTileDataset const* textureLayer, TileId const& tileId, DownloadUsage const usage)
{
    // FIXME: textureLayer->fileFormat() could be used in the future for use just that parser, instead of all available parsers

    QString const fileName = tileFileName(textureLayer, tileId);
    TileStatus status      = tileStatus(textureLayer, tileId);

    if (status != Missing)
    {
        // check if an update should be triggered

        if (status == Available)
        {
            qCDebug(DIGIKAM_GEOENGINE_LOG) << Q_FUNC_INFO << tileId << "StateUptodate";
        }

        else
        {
            Q_ASSERT(status == Expired);

            qCDebug(DIGIKAM_GEOENGINE_LOG) << Q_FUNC_INFO << tileId << "StateExpired";
            triggerDownload(textureLayer, tileId, usage);
        }

        QFile file(fileName);

        if (file.exists())
        {

            // File is ready, so parse and return the vector data in any case

            GeoDataDocument* document = openVectorFile(fileName);

            if (document)
            {
                return document;
            }
        }
    }

    else
    {
        // tile was not locally available => trigger download

        triggerDownload(textureLayer, tileId, usage);
    }

    return nullptr;
}

// This method triggers a download of the given tile (without checking
// expiration). It is called by upper layer (StackedTileLoader) when the tile
// that should be reloaded is currently loaded in memory.
//
// post condition
//     - download is triggered
void TileLoader::downloadTile(GeoSceneTileDataset const* tileData, TileId const& tileId, DownloadUsage const usage)
{
    triggerDownload(tileData, tileId, usage);
}

int TileLoader::maximumTileLevel(GeoSceneTileDataset const& tileData)
{
    // if maximum tile level is configured in the DGML files,
    // then use it, otherwise use old detection code.

    if (tileData.maximumTileLevel() >= 0)
    {
        return tileData.maximumTileLevel();
    }

    int maximumTileLevel   = -1;
    const QFileInfo themeStr(tileData.themeStr());
    const QString tilepath = themeStr.isAbsolute() ? themeStr.absoluteFilePath() : MarbleDirs::path(tileData.themeStr());
    //    qCDebug(DIGIKAM_GEOENGINE_LOG) << "StackedTileLoader::maxPartialTileLevel tilepath" << tilepath;
    QStringList leveldirs  = QDir(tilepath).entryList(QDir::AllDirs | QDir::NoSymLinks
                                                      | QDir::NoDotAndDotDot);

    QStringList::const_iterator it        = leveldirs.constBegin();
    QStringList::const_iterator const end = leveldirs.constEnd();

    for ( ; it != end ; ++it)
    {
        bool ok         = true;
        const int value = (*it).toInt(&ok, 10);

        if (ok && (value > maximumTileLevel))
        {
            maximumTileLevel = value;
        }
    }

    //    qCDebug(DIGIKAM_GEOENGINE_LOG) << "Detected maximum tile level that contains data: "
    //             << maxtilelevel;

    return maximumTileLevel + 1;
}

bool TileLoader::baseTilesAvailable(GeoSceneTileDataset const& tileData)
{
    const int  levelZeroColumns = tileData.levelZeroColumns();
    const int  levelZeroRows    = tileData.levelZeroRows();
    bool result                 = true;

    // Check whether the tiles from the lowest texture level are available

    for (int column = 0 ; result && column < levelZeroColumns ; ++column)
    {
        for (int row = 0 ; result && row < levelZeroRows ; ++row)
        {
            const TileId id(0, 0, column, row);
            const QString tilepath = tileFileName(&tileData, id);
            result                &= QFile::exists(tilepath);

            if (!result)
            {
                qCDebug(DIGIKAM_GEOENGINE_LOG) << "Base tile " << tileData.relativeTileFileName(id)
                                            << " is missing for source dir " << tileData.sourceDir();
            }
        }
    }

    return result;
}

TileLoader::TileStatus TileLoader::tileStatus(GeoSceneTileDataset const* tileData, const TileId& tileId)
{
    QString const fileName = tileFileName(tileData, tileId);
    QFileInfo fileInfo(fileName);

    if (!fileInfo.exists())
    {
        return Missing;
    }

    const QDateTime lastModified = fileInfo.lastModified();
    const int expireSecs = tileData->expire();
    const bool isExpired = lastModified.secsTo(QDateTime::currentDateTime()) >= expireSecs;

    return isExpired ? Expired : Available;
}

void TileLoader::updateTile(QByteArray const& data, QString const& idStr)
{
    QStringList const components = idStr.split(QLatin1Char(':'), Qt::SkipEmptyParts);

    Q_ASSERT(components.size() == 5);

    QString const origin    = components[0];
    QString const sourceDir = components[ 1 ];
    int const zoomLevel     = components[ 2 ].toInt();
    int const tileX         = components[ 3 ].toInt();
    int const tileY         = components[ 4 ].toInt();
    TileId const id         = TileId(sourceDir, zoomLevel, tileX, tileY);

    if (origin == QString::fromUtf8(GeoSceneTypes::GeoSceneTextureTileType))
    {
        QImage const tileImage = QImage::fromData(data);

        if (tileImage.isNull())
        {
            return;
        }

        Q_EMIT tileCompleted(id, tileImage);
    }
}

void TileLoader::updateTile(const QString& fileName, const QString& idStr)
{
    QStringList const components = idStr.split(QLatin1Char(':'), Qt::SkipEmptyParts);

    Q_ASSERT(components.size() == 5);

    QString const origin    = components[0];
    QString const sourceDir = components[ 1 ];
    int const zoomLevel     = components[ 2 ].toInt();
    int const tileX         = components[ 3 ].toInt();
    int const tileY         = components[ 4 ].toInt();
    TileId const id         = TileId(sourceDir, zoomLevel, tileX, tileY);

    if (origin == QString::fromUtf8(GeoSceneTypes::GeoSceneVectorTileType))
    {
        GeoDataDocument* document = openVectorFile(MarbleDirs::path(fileName));

        if (document)
        {
            Q_EMIT tileCompleted(id,  document);
        }
    }
}

QString TileLoader::tileFileName(GeoSceneTileDataset const* tileData, TileId const& tileId)
{
    QString const fileName = tileData->relativeTileFileName(tileId);
    QFileInfo const dirInfo(fileName);

    return dirInfo.isAbsolute() ? fileName : MarbleDirs::path(fileName);
}

void TileLoader::triggerDownload(GeoSceneTileDataset const* tileData, TileId const& id, DownloadUsage const usage)
{
    if (id.zoomLevel() > 0)
    {
        int minValue = (tileData->maximumTileLevel() == -1) ? id.zoomLevel()
                                                            : qMin(id.zoomLevel(), tileData->maximumTileLevel());

        if (id.zoomLevel() != qMax(tileData->minimumTileLevel(), minValue))
        {
            // Download only level 0 tiles and tiles between minimum and maximum tile level

            return;
        }
    }

    QUrl const sourceUrl       = tileData->downloadUrl(id);
    QString const destFileName = tileData->relativeTileFileName(id);
    QString const idStr        = QString::fromUtf8("%1:%2:%3:%4:%5").arg(QString::fromUtf8(tileData->nodeType()), tileData->sourceDir()).arg(id.zoomLevel()).arg(id.x()).arg(id.y());

    Q_EMIT downloadTile(sourceUrl, destFileName, idStr, usage);
}

QImage TileLoader::scaledLowerLevelTile(const GeoSceneTextureTileDataset* textureData, TileId const& id)
{
    qCDebug(DIGIKAM_GEOENGINE_LOG) << Q_FUNC_INFO << id;

    int const minimumLevel = textureData->minimumTileLevel();

    for (int level = qMax<int>(0, id.zoomLevel() - 1) ; level >= 0 ; --level)
    {
        if (level > 0 && level < minimumLevel)
        {
            continue;
        }

        int const deltaLevel = id.zoomLevel() - level;

        TileId const replacementTileId(id.mapThemeIdHash(), level,
                                       id.x() >> deltaLevel, id.y() >> deltaLevel);
        QString const fileName = tileFileName(textureData, replacementTileId);
        qCDebug(DIGIKAM_GEOENGINE_LOG) << "TileLoader::scaledLowerLevelTile" << "trying" << fileName;
        QImage toScale = (!fileName.isEmpty() && QFile::exists(fileName)) ? QImage(fileName) : QImage();

        if (level == 0 && toScale.isNull())
        {
            qCDebug(DIGIKAM_GEOENGINE_LOG) << "No level zero tile installed in map theme dir. Falling back to a transparent image for now.";
            QSize tileSize = textureData->tileSize();

            Q_ASSERT(!tileSize.isEmpty());   // assured by textureLayer

            toScale = QImage(tileSize, QImage::Format_ARGB32_Premultiplied);
            toScale.fill(qRgba(0, 0, 0, 0));
        }

        if (!toScale.isNull())
        {
            // which rect to scale?

            int const restTileX = id.x() % (1 << deltaLevel);
            int const restTileY = id.y() % (1 << deltaLevel);
            int const partWidth = qMax(1, toScale.width() >> deltaLevel);
            int const partHeight = qMax(1, toScale.height() >> deltaLevel);
            int const startX = restTileX * partWidth;
            int const startY = restTileY * partHeight;
            qCDebug(DIGIKAM_GEOENGINE_LOG) << "QImage::copy:" << startX << startY << partWidth << partHeight;
            QImage const part = toScale.copy(startX, startY, partWidth, partHeight);
            qCDebug(DIGIKAM_GEOENGINE_LOG) << "QImage::scaled:" << toScale.size();

            return part.scaled(toScale.size());
        }
    }

    Q_ASSERT_X(false, "scaled image", "level zero image missing");   // not reached

    return QImage();
}

GeoDataDocument* TileLoader::openVectorFile(const QString& fileName) const
{
    QList<const ParseRunnerPlugin*> plugins = m_pluginManager->parsingRunnerPlugins();
    const QFileInfo fileInfo(fileName);
    const QString suffix = fileInfo.suffix().toLower();
    const QString completeSuffix = fileInfo.completeSuffix().toLower();

    for (const ParseRunnerPlugin* plugin : plugins)
    {
        QStringList const extensions = plugin->fileExtensions();

        if (extensions.contains(suffix) || extensions.contains(completeSuffix))
        {
            ParsingRunner* runner = plugin->newRunner();
            QString error;
            GeoDataDocument* document = runner->parseFile(fileName, UserDocument, error);

            if (!document && !error.isEmpty())
            {
                qCDebug(DIGIKAM_GEOENGINE_LOG) << QString::fromUtf8("Failed to open vector tile %1: %2").arg(fileName, error);
            }

            delete runner;

            return document;
        }
    }

    qCDebug(DIGIKAM_GEOENGINE_LOG) << "Unable to open vector tile " << fileName << ": No suitable plugin registered to parse this file format";

    return nullptr;
}

} // namespace Digikam

#include "moc_TileLoader.cpp"
