/* ============================================================
 *
 * 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 "AbstractDataPluginModel.h"

// C++ includes

#include <cmath>

// Qt includes

#include <QTimer>
#include <QPointF>
#include <QRectF>
#include <QtAlgorithms>
#include <QVariant>
#include <QAbstractListModel>
#include <QMetaProperty>

// Local includes

#include "AbstractDataPluginItem.h"
#include "CacheStoragePolicy.h"
#include "GeoDataCoordinates.h"
#include "GeoDataLatLonAltBox.h"
#include "HttpDownloadManager.h"
#include "MarbleModel.h"
#include "MarbleDirs.h"
#include "ViewportParams.h"
#include "digikam_debug.h"

namespace Marble
{

const QString descriptionPrefix(QString::fromUtf8("description_"));

// Time between two tried description file downloads (we decided not to download anything) in ms

const int timeBetweenTriedDownloads = 500;

// Time between two real description file downloads in ms

const int timeBetweenDownloads = 1500;

// The factor describing how much the box has to be changed to download a new description file.
// A higher factor means more downloads.

const qreal boxComparisonFactor = 16.0;

// Separator to separate the id of the item from the file type

const QChar fileIdSeparator = QLatin1Char('_');

class FavoritesModel;

class Q_DECL_HIDDEN AbstractDataPluginModelPrivate
{
public:

    AbstractDataPluginModelPrivate(const QString& name,
                                   const MarbleModel* marbleModel,
                                   AbstractDataPluginModel* parent);

    ~AbstractDataPluginModelPrivate();

    static QString generateFilename(const QString& id, const QString& type);
    QString generateFilepath(const QString& id, const QString& type) const;

    void updateFavoriteItems();

public:

    AbstractDataPluginModel*                    m_parent            = nullptr;
    const QString                               m_name;
    const MarbleModel* const                    m_marbleModel       = nullptr;
    GeoDataLatLonAltBox                         m_lastBox;
    GeoDataLatLonAltBox                         m_downloadedBox;
    qint32                                      m_lastNumber;
    qint32                                      m_downloadedNumber;
    QString                                     m_currentPlanetId;
    QList<AbstractDataPluginItem*>              m_itemSet;
    QHash<QString, AbstractDataPluginItem*>     m_downloadingItems;
    QList<AbstractDataPluginItem*>              m_displayedItems;
    QTimer                                      m_downloadTimer;
    quint32                                     m_descriptionFileNumber;
    QHash<QString, QVariant>                    m_itemSettings;
    QStringList                                 m_favoriteItems;
    bool                                        m_favoriteItemsOnly;

    CacheStoragePolicy                          m_storagePolicy;
    HttpDownloadManager                         m_downloadManager;
    FavoritesModel*                             m_favoritesModel    = nullptr;
    QMetaObject                                 m_metaObject;
    bool                                        m_hasMetaObject;
    bool                                        m_needsSorting;
};

class Q_DECL_HIDDEN FavoritesModel : public QAbstractListModel
{
    Q_OBJECT

public:

    AbstractDataPluginModelPrivate* d = nullptr;

public:

    explicit FavoritesModel(AbstractDataPluginModelPrivate* d, QObject* parent = nullptr);

    int rowCount(const QModelIndex& parent = QModelIndex()) const override;

    QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const override;

    void reset();

    QHash<int, QByteArray> roleNames() const override;

private:

    QHash<int, QByteArray> m_roleNames;
};

AbstractDataPluginModelPrivate::AbstractDataPluginModelPrivate(const QString& name,
                                                               const MarbleModel* marbleModel,
                                                               AbstractDataPluginModel* parent)
    : m_parent(parent),
      m_name(name),
      m_marbleModel(marbleModel),
      m_lastBox(),
      m_downloadedBox(),
      m_lastNumber(0),
      m_downloadedNumber(0),
      m_currentPlanetId(marbleModel->planetId()),
      m_downloadTimer(m_parent),
      m_descriptionFileNumber(0),
      m_itemSettings(),
      m_favoriteItemsOnly(false),
      m_storagePolicy(MarbleDirs::localPath() + QLatin1String("/cache/") + m_name + QLatin1Char('/')),
      m_downloadManager(&m_storagePolicy),
      m_favoritesModel(nullptr),
      m_hasMetaObject(false),
      m_needsSorting(false)
{
}

AbstractDataPluginModelPrivate::~AbstractDataPluginModelPrivate()
{
    QList<AbstractDataPluginItem*>::iterator lIt          = m_itemSet.begin();
    QList<AbstractDataPluginItem*>::iterator const lItEnd = m_itemSet.end();

    for ( ; lIt != lItEnd ; ++lIt)
    {
        (*lIt)->deleteLater();
    }

    QHash<QString, AbstractDataPluginItem*>::iterator hIt          = m_downloadingItems.begin();
    QHash<QString, AbstractDataPluginItem*>::iterator const hItEnd = m_downloadingItems.end();

    for ( ; hIt != hItEnd ; ++hIt)
    {
        (*hIt)->deleteLater();
    }

    m_storagePolicy.clearCache();
}

void AbstractDataPluginModelPrivate::updateFavoriteItems()
{
    if (m_favoriteItemsOnly)
    {
        for (const QString& id : m_favoriteItems)
        {
            if (!m_parent->findItem(id))
            {
                m_parent->getItem(id);
            }
        }
    }
}

void AbstractDataPluginModel::themeChanged()
{
    if (d->m_currentPlanetId != d->m_marbleModel->planetId())
    {
        clear();
        d->m_currentPlanetId = d->m_marbleModel->planetId();
    }
}

static bool lessThanByPointer(const AbstractDataPluginItem* item1,
                              const AbstractDataPluginItem* item2)
{
    if (item1 && item2)
    {
        // Compare by sticky and favorite status (sticky first, then favorites), last by operator<

        bool const sticky1   = item1->isSticky();
        bool const favorite1 = item1->isFavorite();

        if      (sticky1 != item2->isSticky())
        {
            return sticky1;
        }
        else if (favorite1 != item2->isFavorite())
        {
            return favorite1;
        }
        else
        {
            return item1->operator<(item2);
        }
    }

    else
    {
        return false;
    }
}

FavoritesModel::FavoritesModel(AbstractDataPluginModelPrivate* _d, QObject* parent) :
    QAbstractListModel(parent), d(_d)
{
    QHash<int, QByteArray> roles;
    int const size = d->m_hasMetaObject ? d->m_metaObject.propertyCount() : 0;

    for (int i = 0 ; i < size ; ++i)
    {
        QMetaProperty property  = d->m_metaObject.property(i);
        roles[Qt::UserRole + i] = property.name();
    }

    roles[Qt::DisplayRole]    = "display";
    roles[Qt::DecorationRole] = "decoration";
    m_roleNames               = roles;
}

int FavoritesModel::rowCount(const QModelIndex& parent) const
{
    if (parent.isValid())
    {
        return 0;
    }

    int count = 0;

    for (AbstractDataPluginItem* item : d->m_itemSet)
    {
        if (item->initialized() && item->isFavorite())
        {
            ++count;
        }
    }

    return count;
}

QVariant FavoritesModel::data(const QModelIndex& index, int role) const
{
    int const row = index.row();

    if ((row >= 0) && (row < rowCount()))
    {
        int count = 0;

        for (AbstractDataPluginItem* item : d->m_itemSet)
        {
            if (item->initialized() && item->isFavorite())
            {
                if (count == row)
                {
                    QString const roleName = QString::fromUtf8(roleNames().value(role));

                    return item->property(roleName.toLatin1().constData());
                }

                ++count;
            }
        }
    }

    return QVariant();
}

void FavoritesModel::reset()
{
    beginResetModel();
    endResetModel();
}

QHash<int, QByteArray> FavoritesModel::roleNames() const
{
    return m_roleNames;
}

AbstractDataPluginModel::AbstractDataPluginModel(const QString& name, const MarbleModel* marbleModel, QObject* parent)
    : QObject(parent),
      d      (new AbstractDataPluginModelPrivate(name, marbleModel, this))
{
    Q_ASSERT(marbleModel != nullptr);

    // Initializing file and download System

    connect(&d->m_downloadManager, SIGNAL(downloadComplete(QString,QString)),
            this, SLOT(processFinishedJob(QString,QString)));

    connect(marbleModel, SIGNAL(themeChanged(QString)),
            this, SLOT(themeChanged()));

    // We want to download a new description file every timeBetweenDownloads ms

    connect(&d->m_downloadTimer, SIGNAL(timeout()),
            this, SLOT(handleChangedViewport()),
            Qt::QueuedConnection);

    d->m_downloadTimer.start(timeBetweenDownloads);
}

AbstractDataPluginModel::~AbstractDataPluginModel()
{
    delete d;
}

const MarbleModel* AbstractDataPluginModel::marbleModel() const
{
    return d->m_marbleModel;
}

QList<AbstractDataPluginItem*> AbstractDataPluginModel::items(const ViewportParams* viewport,
                                                              qint32 number)
{
    GeoDataLatLonAltBox currentBox = viewport->viewLatLonAltBox();
    QList<AbstractDataPluginItem*> list;

    Q_ASSERT(!d->m_displayedItems.contains(nullptr) && "Null item in m_displayedItems. Please report a bug to marble-devel@kde.org");
    Q_ASSERT(!d->m_itemSet.contains(nullptr) && "Null item in m_itemSet. Please report a bug to marble-devel@kde.org");

    QList<AbstractDataPluginItem*> candidates = d->m_displayedItems + d->m_itemSet;

    if (d->m_needsSorting)
    {
        // Both the candidates list and the list of all items need to be sorted

        std::sort(candidates.begin(), candidates.end(), lessThanByPointer);
        std::sort(d->m_itemSet.begin(), d->m_itemSet.end(), lessThanByPointer);
        d->m_needsSorting =  false;
    }

    QList<AbstractDataPluginItem*>::const_iterator i   = candidates.constBegin();
    QList<AbstractDataPluginItem*>::const_iterator end = candidates.constEnd();

    // Items that are already shown have the highest priority

    for ( ; i != end && list.size() < number ; ++i)
    {
        // Only show items that are initialized

        if (!(*i)->initialized())
        {
            continue;
        }

        // Hide non-favorite items if necessary

        if (d->m_favoriteItemsOnly && !(*i)->isFavorite())
        {
            continue;
        }

        (*i)->setProjection(viewport);

        if ((*i)->positions().isEmpty())
        {
            continue;
        }

        if (list.contains(*i))
        {
            continue;
        }

        // If the item was added initially at a nearer position, they don't have priority,
        // because we zoomed out since then.

        bool const alreadyDisplayed = d->m_displayedItems.contains(*i);

        if (!alreadyDisplayed || (*i)->addedAngularResolution() >= viewport->angularResolution() || (*i)->isSticky())
        {
            bool collides = false;
            int const length = list.length();

            for (int j = 0 ; !collides && j < length ; ++j)
            {
                for (const QRectF& rect : list[j]->boundingRects())
                {
                    for (const QRectF& itemRect : (*i)->boundingRects())
                    {
                        if (rect.intersects(itemRect))
                        {
                            collides = true;
                        }
                    }
                }
            }

            if (!collides)
            {
                list.append(*i);
                (*i)->setSettings(d->m_itemSettings);

                // We want to save the angular resolution of the first time the item got added.

                if (!alreadyDisplayed)
                {
                    (*i)->setAddedAngularResolution(viewport->angularResolution());
                }
            }
        }

        // TODO: Do we have to cleanup at some point? The list of all items keeps growing
    }

    d->m_lastBox        = currentBox;
    d->m_lastNumber     = number;
    d->m_displayedItems = list;

    return list;
}

QList<AbstractDataPluginItem*> AbstractDataPluginModel::whichItemAt(const QPoint& curpos)
{
    QList<AbstractDataPluginItem*> itemsAt;

    const QPointF curposF(curpos);

    for (AbstractDataPluginItem* item : d->m_displayedItems)
    {
        if (item && item->contains(curposF))
        {
            itemsAt.append(item);
        }
    }

    return itemsAt;
}

void AbstractDataPluginModel::parseFile(const QByteArray& file)
{
    Q_UNUSED(file);
}

void AbstractDataPluginModel::downloadItem(const QUrl& url,
                                           const QString& type,
                                           AbstractDataPluginItem* item)
{
    if (!item)
    {
        return;
    }

    QString id = d->generateFilename(item->id(), type);

    d->m_downloadManager.addJob(url, id, id, DownloadBrowse);
    d->m_downloadingItems.insert(id, item);
}

void AbstractDataPluginModel::downloadDescriptionFile(const QUrl& url)
{
    if (!url.isEmpty())
    {
        QString name(descriptionPrefix);
        name += QString::number(d->m_descriptionFileNumber);

        d->m_downloadManager.addJob(url, name, name, DownloadBrowse);
        d->m_descriptionFileNumber++;
    }
}

void AbstractDataPluginModel::addItemToList(AbstractDataPluginItem* item)
{
    addItemsToList(QList<AbstractDataPluginItem*>() << item);
}

void AbstractDataPluginModel::addItemsToList(const QList<AbstractDataPluginItem*>& items)
{
    bool needsUpdate     = false;
    bool favoriteChanged = false;

    for (AbstractDataPluginItem* item : items)
    {
        if (!item)
        {
            continue;
        }

        // If the item is already in our list, don't add it.

        if (d->m_itemSet.contains(item))
        {
            continue;
        }

        if (itemExists(item->id()))
        {
            item->deleteLater();

            continue;
        }

        qCDebug(DIGIKAM_GEOENGINE_LOG) << "New item " << item->id();

        // This find the right position in the sorted to insert the new item

        QList<AbstractDataPluginItem*>::iterator i = std::lower_bound(d->m_itemSet.begin(),
                                                                      d->m_itemSet.end(),
                                                                      item,
                                                                      lessThanByPointer);
        // Insert the item on the right position in the list

        d->m_itemSet.insert(i, item);

        connect(item, SIGNAL(stickyChanged()),
                this, SLOT(scheduleItemSort()));

        connect(item, SIGNAL(destroyed(QObject*)),
                this, SLOT(removeItem(QObject*)));

        connect(item, SIGNAL(updated()),
                this, SIGNAL(itemsUpdated()));

        connect(item, SIGNAL(favoriteChanged(QString,bool)),
                this, SLOT(favoriteItemChanged(QString,bool)));

        if (!needsUpdate && item->initialized())
        {
            needsUpdate = true;
        }

        if (!favoriteChanged && item->initialized() && item->isFavorite())
        {
            favoriteChanged = true;
        }
    }

    if (favoriteChanged && d->m_favoritesModel)
    {
        d->m_favoritesModel->reset();
    }

    if (needsUpdate)
    {
        Q_EMIT itemsUpdated();
    }
}

void AbstractDataPluginModel::getItem(const QString&)
{
    qCWarning(DIGIKAM_GEOENGINE_LOG) << "Retrieving items by identifier is not implemented by this plugin";
}

void AbstractDataPluginModel::setFavoriteItems(const QStringList& list)
{
    if (d->m_favoriteItems != list)
    {
        d->m_favoriteItems = list;
        d->updateFavoriteItems();

        if (d->m_favoritesModel)
        {
            d->m_favoritesModel->reset();
        }

        Q_EMIT favoriteItemsChanged(d->m_favoriteItems);
    }
}

QStringList AbstractDataPluginModel::favoriteItems() const
{
    return d->m_favoriteItems;
}

void AbstractDataPluginModel::setFavoriteItemsOnly(bool favoriteOnly)
{
    if (isFavoriteItemsOnly() != favoriteOnly)
    {
        d->m_favoriteItemsOnly = favoriteOnly;
        d->updateFavoriteItems();

        Q_EMIT favoriteItemsOnlyChanged();
    }
}

bool AbstractDataPluginModel::isFavoriteItemsOnly() const
{
    return d->m_favoriteItemsOnly;
}

QObject* AbstractDataPluginModel::favoritesModel()
{
    if (!d->m_favoritesModel)
    {
        d->m_favoritesModel = new FavoritesModel(d, this);
        d->updateFavoriteItems();
    }

    return d->m_favoritesModel;
}

void AbstractDataPluginModel::favoriteItemChanged(const QString& id, bool isFavorite)
{
    QStringList favorites = d->m_favoriteItems;

    if (isFavorite)
    {
        if (!favorites.contains(id))
        {
            favorites.append(id);
        }
    }

    else
    {
        favorites.removeOne(id);
    }

    setFavoriteItems(favorites);
    scheduleItemSort();
}

void AbstractDataPluginModel::scheduleItemSort()
{
    d->m_needsSorting = true;
}

QString AbstractDataPluginModelPrivate::generateFilename(const QString& id, const QString& type)
{
    QString name;
    name += id;
    name += fileIdSeparator;
    name += type;

    return name;
}

QString AbstractDataPluginModelPrivate::generateFilepath(const QString& id, const QString& type) const
{
    return MarbleDirs::localPath() + QLatin1String("/cache/") + m_name + QLatin1Char('/') + generateFilename(id, type);
}

AbstractDataPluginItem* AbstractDataPluginModel::findItem(const QString& id) const
{
    for (AbstractDataPluginItem* item : d->m_itemSet)
    {
        if (item->id() == id)
        {
            return item;
        }
    }

    return nullptr;
}

bool AbstractDataPluginModel::itemExists(const QString& id) const
{
    return findItem(id);
}

void AbstractDataPluginModel::setItemSettings(const QHash<QString, QVariant>& itemSettings)
{
    d->m_itemSettings = itemSettings;
}

void AbstractDataPluginModel::handleChangedViewport()
{
    if (d->m_favoriteItemsOnly)
    {
        return;
    }

    // All this is to prevent to often downloads

    if (d->m_lastNumber != 0

        // We don't need to download if nothing changed

        && (!(d->m_downloadedBox == d->m_lastBox)
            || d->m_downloadedNumber != d->m_lastNumber)

        // We try to filter little changes of the bounding box

        && (fabs(d->m_downloadedBox.east() - d->m_lastBox.east()) * boxComparisonFactor
            > d->m_lastBox.width()
            || fabs(d->m_downloadedBox.south() - d->m_lastBox.south()) * boxComparisonFactor
            > d->m_lastBox.height()
            || fabs(d->m_downloadedBox.north() - d->m_lastBox.north()) * boxComparisonFactor
            > d->m_lastBox.height()
            || fabs(d->m_downloadedBox.west() - d->m_lastBox.west()) * boxComparisonFactor
            > d->m_lastBox.width()))
    {
        // We will wait a little bit longer to start the
        // next download as we will really download something now.

        d->m_downloadTimer.setInterval(timeBetweenDownloads);

        // Save the download parameter

        d->m_downloadedBox = d->m_lastBox;
        d->m_downloadedNumber = d->m_lastNumber;

        // Get items

        getAdditionalItems(d->m_lastBox, d->m_lastNumber);
    }
    else
    {
        // Don't wait to long to start the next download as we decided not to download anything.
        // This will enhance response.

        d->m_downloadTimer.setInterval(timeBetweenTriedDownloads);
    }
}

void AbstractDataPluginModel::processFinishedJob(const QString& relativeUrlString,
                                                 const QString& id)
{
    Q_UNUSED(relativeUrlString);

    if (id.startsWith(descriptionPrefix))
    {
        parseFile(d->m_storagePolicy.data(id));
    }
    else
    {
        // The downloaded file contains item data.

        // Splitting the id in itemId and fileType

        QStringList fileInformation = id.split(fileIdSeparator);

        if (fileInformation.size() < 2)
        {
            qCDebug(DIGIKAM_GEOENGINE_LOG) << "Strange file information " << id;
            return;
        }

        QString itemId   = fileInformation.at(0);
        fileInformation.removeAt(0);
        QString fileType = fileInformation.join(QString(fileIdSeparator));

        // Searching for the right item in m_downloadingItems

        QHash<QString, AbstractDataPluginItem*>::iterator i = d->m_downloadingItems.find(id);

        if (i != d->m_downloadingItems.end())
        {
            if (itemId != (*i)->id())
            {
                return;
            }

            (*i)->addDownloadedFile(d->generateFilepath(itemId, fileType),
                                    fileType);

            d->m_downloadingItems.erase(i);
        }
    }
}

void AbstractDataPluginModel::removeItem(QObject* item)
{
    AbstractDataPluginItem* pluginItem = qobject_cast<AbstractDataPluginItem*>(item);
    d->m_itemSet.removeAll(pluginItem);
    QHash<QString, AbstractDataPluginItem*>::iterator i;

    for (i = d->m_downloadingItems.begin(); i != d->m_downloadingItems.end(); ++i)
    {
        if (*i == pluginItem)
        {
            i = d->m_downloadingItems.erase(i);
        }
    }
}

void AbstractDataPluginModel::clear()
{
    d->m_displayedItems.clear();
    QList<AbstractDataPluginItem*>::iterator iter      = d->m_itemSet.begin();
    QList<AbstractDataPluginItem*>::iterator const end = d->m_itemSet.end();

    for (; iter != end; ++iter)
    {
        (*iter)->deleteLater();
    }

    d->m_itemSet.clear();
    d->m_lastBox          = GeoDataLatLonAltBox();
    d->m_downloadedBox    = GeoDataLatLonAltBox();
    d->m_downloadedNumber = 0;

    Q_EMIT itemsUpdated();
}

void AbstractDataPluginModel::registerItemProperties(const QMetaObject& item)
{
    d->m_metaObject    = item;
    d->m_hasMetaObject = true;
}

} // namespace Marble

#include "AbstractDataPluginModel.moc"
#include "moc_AbstractDataPluginModel.cpp"
