/*
    SPDX-FileCopyrightText: 2010 Jens-Michael Hoffmann <jmho@c-xx.com>
    SPDX-FileCopyrightText: 2010-2012 Bernhard Beschow <bbeschow@cs.tu-berlin.de>

    SPDX-License-Identifier: LGPL-2.1-or-later
*/

#include "TileLoader.h"

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

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

Q_DECLARE_METATYPE(Marble::DownloadUsage)

namespace Marble
{

TileLoader::TileLoader(HttpDownloadManager *const downloadManager, const PluginManager *pluginManager)
    : m_pluginManager(pluginManager)
{
    qRegisterMetaType<DownloadUsage>("DownloadUsage");
    connect(this, &TileLoader::tileRequested, downloadManager, &HttpDownloadManager::addJob);
    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) {
            mDebug() << tileId << "StateUptodate";
        } else {
            Q_ASSERT(status == Expired);
            mDebug() << 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) {
            mDebug() << tileId << "StateUptodate";
        } else {
            Q_ASSERT(status == Expired);
            mDebug() << 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());
    //    mDebug() << "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;
    }

    //    mDebug() << "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) {
                mDebug() << "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::fromLatin1(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::fromLatin1(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::cacheFilePath(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 =
        QStringLiteral("%1:%2:%3:%4:%5").arg(QString::fromLatin1(tileData->nodeType()), tileData->sourceDir()).arg(id.zoomLevel()).arg(id.x()).arg(id.y());
    Q_EMIT tileRequested(sourceUrl, destFileName, idStr, usage);
}

QImage TileLoader::scaledLowerLevelTile(const GeoSceneTextureTileDataset *textureData, TileId const &id)
{
    mDebug() << 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);
        mDebug() << "TileLoader::scaledLowerLevelTile"
                 << "trying" << fileName;
        QImage toScale = (!fileName.isEmpty() && QFile::exists(fileName)) ? QImage(fileName) : QImage();

        if (level == 0 && toScale.isNull()) {
            mDebug() << "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;
            mDebug() << "QImage::copy:" << startX << startY << partWidth << partHeight;
            QImage const part = toScale.copy(startX, startY, partWidth, partHeight);
            mDebug() << "QImage::scaled:" << toScale.size();
            return part.scaled(toScale.size());
        }
    }

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

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 : std::as_const(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()) {
                mDebug() << QStringLiteral("Failed to open vector tile %1: %2").arg(fileName, error);
            }
            delete runner;
            return document;
        }
    }

    mDebug() << "Unable to open vector tile " << fileName << ": No suitable plugin registered to parse this file format";
    return nullptr;
}

}

#include "moc_TileLoader.cpp"
