galleryviews.cpp

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#include "galleryviews.h"

#include <cmath> // for qsrand
#include <random>
#if QT_VERSION >= QT_VERSION_CHECK(5,10,0)
#include <QRandomGenerator>
#endif

#define LOC QString("Galleryviews: ")

const static int   kMaxFolderThumbnails = 4;

const double LEADING_BETA_SHAPE  = 0.175;
const double TRAILING_BETA_SHAPE = 0.31;

const double DEFAULT_WEIGHT = std::pow(0.5, TRAILING_BETA_SHAPE - 1) *
                              std::pow(0.5, LEADING_BETA_SHAPE - 1);
const qint64 BETA_CLIP = 60 * 60 * 24;


ImageListK FlatView::GetAllNodes() const
{
    ImageListK files;
    foreach (int id, m_sequence)
        files.append(m_images.value(id));
    return files;
}


ImagePtrK FlatView::GetSelected() const
{
    return m_active < 0 || m_active >= m_sequence.size()
            ? ImagePtrK() : m_images.value(m_sequence.at(m_active));
}


QString FlatView::GetPosition() const
{
    return QString("%1/%2").arg(m_active + 1).arg(m_sequence.size());
}


bool FlatView::Update(int id)
{
    ImagePtrK im = m_images.value(id);
    if (!im)
        return false;

    // Get updated image
    ImageList files, dirs;
    ImageIdList ids = ImageIdList() << id;
    if (m_mgr.GetImages(ids, files, dirs) != 1 || files.size() != 1)
        return false;

    bool active = (im == GetSelected());

    // Replace image
    m_images.insert(id, files.at(0));

    LOG(VB_FILE, LOG_DEBUG, LOC + QString("Modified id %1").arg(id));

    return active;
}


bool FlatView::Select(int id, int fallback)
{
    // Select first appearance of image
    int index = m_sequence.indexOf(id);
    if (index >= 0)
    {
        m_active = index;
        return true;
    }

    if (fallback >= 0)
        m_active = fallback;

    return false;
}


void FlatView::Clear(bool resetParent)
{
    m_images.clear();
    m_sequence.clear();
    m_active = -1;
    if (resetParent)
        m_parentId = GALLERY_DB_ID;
}


ImagePtrK FlatView::HasNext(int inc) const
{
    return m_sequence.isEmpty() || m_active + inc >= m_sequence.size()
            ? ImagePtrK() : m_images.value(m_sequence.at(m_active + inc));
}


ImagePtrK FlatView::Next(int inc)
{
    if (m_sequence.isEmpty())
        return ImagePtrK();

    // Preserve index as it may be reset when wrapping
    int next = m_active + inc;

    // Regenerate unordered views when wrapping
    if (next >= m_sequence.size() && m_order != kOrdered && !LoadFromDb(m_parentId))
        // Images have disappeared
        return ImagePtrK();

    m_active = next % m_sequence.size();
    return m_images.value(m_sequence.at(m_active));
}


ImagePtrK FlatView::HasPrev(int inc) const
{
    return m_sequence.isEmpty() || m_active < inc
            ? ImagePtrK() : m_images.value(m_sequence.at(m_active - inc));
}


ImagePtrK FlatView::Prev(int inc)
{
    if (m_sequence.isEmpty())
        return ImagePtrK();

    // Wrap avoiding modulo of negative uncertainty
    m_active -= inc % m_sequence.size();
    if (m_active < 0)
        m_active += m_sequence.size();

    return m_images.value(m_sequence.at(m_active));
}


void FlatView::Populate(ImageList &files)
{
    // Do not reset parent
    Clear(false);

    if (files.isEmpty())
        return;

    foreach (ImagePtrK im, files)
    {
        // Add image to view
        m_images.insert(im->m_id, im);

        // Cache all displayed images
        if (im->IsFile())
            Cache(im->m_id, im->m_parentId, im->m_url, im->m_thumbNails.at(0).second);
    }

    if (files.size() == 1 || m_order == kOrdered || m_order == kShuffle)
    {
        // Default sequence is ordered
        foreach (ImagePtrK im, files)
            m_sequence.append(im->m_id);
    }

    if (files.size() > 1)
    {
        // Modify viewing sequence
        if (m_order == kShuffle)
        {
            std::shuffle(m_sequence.begin(), m_sequence.end(),
                         std::mt19937(std::random_device()()));
        }
        else if (m_order == kRandom)
        {
#if QT_VERSION >= QT_VERSION_CHECK(5,10,0)
            QVector<quint32> rands;
            rands.resize(files.size());
            QRandomGenerator::global()->fillRange(rands.data(), rands.size());
#else
            qsrand(QTime::currentTime().msec());
#endif
            // An image is not a valid candidate for its successor
            int range = files.size() - 1;
            int index = range;
            for (int count = 0; count < files.size(); ++count)
            {
#if QT_VERSION >= QT_VERSION_CHECK(5,10,0)
                int rand = rands[count] % range;
#else
                int rand = qrand() % range;
#endif
                // Avoid consecutive repeats
                index = (rand < index) ? rand : rand + 1;
                m_sequence.append(files.at(index)->m_id);
            }
        }
        else if (m_order == kSeasonal)
        {
            WeightList weights   = CalculateSeasonalWeights(files);
            double     maxWeight = weights.last();

#if QT_VERSION >= QT_VERSION_CHECK(5,10,0)
            auto randgen = QRandomGenerator::global();
#else
            qsrand(QTime::currentTime().msec());
#endif
            for (int count = 0; count < files.size(); ++count)
            {
#if QT_VERSION >= QT_VERSION_CHECK(5,10,0)
                // generateDouble() returns in the range [0, 1)
                double randWeight = randgen->generateDouble() * maxWeight;
#else
                double randWeight = qrand() * maxWeight / RAND_MAX;
#endif
                WeightList::iterator it =
                        std::upper_bound(weights.begin(), weights.end(), randWeight);
                int    index      = std::distance(weights.begin(), it);
                m_sequence.append(files.at(index)->m_id);
            }
        }
    }
}


WeightList FlatView::CalculateSeasonalWeights(ImageList &files)
{
    WeightList weights(files.size());
    double     totalWeight = 0;
    QDateTime  now         = QDateTime::currentDateTime();

    for (int i = 0; i < files.size(); ++i)
    {
        ImagePtrK im = files.at(i);
        double weight = 0;

        if (im->m_date == 0)
            weight = DEFAULT_WEIGHT;
        else
        {
#if QT_VERSION < QT_VERSION_CHECK(5,8,0)
            QDateTime timestamp = QDateTime::fromTime_t(im->m_date);
#else
            QDateTime timestamp = QDateTime::fromSecsSinceEpoch(im->m_date);
#endif
            QDateTime curYearAnniversary =
                    QDateTime(QDate(now.date().year(),
                                    timestamp.date().month(),
                                    timestamp.date().day()),
                              timestamp.time());

            bool isAnniversaryPast = curYearAnniversary < now;

            QDateTime adjacentYearAnniversary =
                    QDateTime(QDate(now.date().year() +
                                    (isAnniversaryPast ? 1 : -1),
                                    timestamp.date().month(),
                                    timestamp.date().day()),
                              timestamp.time());

            double range = llabs(curYearAnniversary.secsTo(
                                   adjacentYearAnniversary)) + BETA_CLIP;

            // This calculation is not normalized, because that would require the
            // beta function, which isn't part of the C++98 libraries. Weights
            // that aren't normalized work just as well relative to each other.
            QDateTime d1(isAnniversaryPast ? curYearAnniversary
                                           : adjacentYearAnniversary);
            QDateTime d2(isAnniversaryPast ? adjacentYearAnniversary
                                           : curYearAnniversary);
            weight = std::pow(llabs(now.secsTo(d1) + BETA_CLIP) / range,
                              TRAILING_BETA_SHAPE - 1)
                    * std::pow(llabs(now.secsTo(d2) + BETA_CLIP) / range,
                               LEADING_BETA_SHAPE - 1);
        }
        totalWeight += weight;
        weights[i]   = totalWeight;
    }
    return weights;
}


bool FlatView::LoadFromDb(int parentId)
{
    m_parentId = parentId;

    // Load child images of the parent
    ImageList files, dirs;
    m_mgr.GetChildren(m_parentId, files, dirs);

    // Load gallery datastore with current dir
    Populate(files);

    return !files.isEmpty();
}


void FlatView::ClearCache()
{
    LOG(VB_FILE, LOG_DEBUG, LOC + "Cleared File cache");
    m_fileCache.clear();
}


QStringList FlatView::ClearImage(int id, bool remove)
{
    if (remove)
    {
        m_sequence.removeAll(id);
        m_images.remove(id);
    }

    QStringList urls;
    FileCacheEntry file = m_fileCache.take(id);

    if (!file.m_url.isEmpty())
        urls << file.m_url;

    if (!file.m_thumbUrl.isEmpty())
        urls << file.m_thumbUrl;

    LOG(VB_FILE, LOG_DEBUG, LOC + QString("Cleared %1 from file cache (%2)")
        .arg(id).arg(urls.join(",")));
    return urls;
}


void FlatView::Rotate(int id)
{
    // Rotate sequence so that (first appearance of) specified image is
    // at offset from front
    int index = m_sequence.indexOf(id);
    if (index >= 0)
    {
        int first = index % m_sequence.size();
        if (first > 0)
            m_sequence = m_sequence.mid(first) + m_sequence.mid(0, first);
    }
}


void FlatView::Cache(int id, int parent, const QString &url, const QString &thumb)
{
    // Cache parent dir so that dir thumbs are updated when a child changes.
    // Also store urls for image cache cleanup
    FileCacheEntry cached(parent, url, thumb);
    m_fileCache.insert(id, cached);
    LOG(VB_FILE, LOG_DEBUG, LOC + "Caching " + cached.ToString(id));
}


QString DirCacheEntry::ToString(int id) const
{
    QStringList ids;
    for (int i = 0; i < m_thumbs.size(); ++i)
        ids << QString::number(m_thumbs.at(i).first);
    return QString("Dir %1 (%2, %3) Thumbs %4 (%5) Parent %6")
            .arg(id).arg(m_fileCount).arg(m_dirCount).arg(ids.join(","))
            .arg(m_thumbCount).arg(m_parent);
}


DirectoryView::DirectoryView(SlideOrderType order)
    : FlatView(order)
{
    m_marked.Clear();
    m_prevMarked.Clear();
}


QString DirectoryView::GetPosition() const
{
    return QString("%1/%2").arg(m_active).arg(m_sequence.size() - 1);
}


bool DirectoryView::LoadFromDb(int parentId)
{
    // Determine parent (defaulting to ancestor) & get initial children
    ImageList files, dirs;
    ImagePtr parent;
    int count = 0;
    // Root is guaranteed to return at least 1 item
    while ((count = m_mgr.GetDirectory(parentId, parent, files, dirs)) == 0)
    {
        // Fallback if dir no longer exists
        // Ascend to Gallery for gallery subdirs, Root for device dirs & Gallery
        parentId = parentId > PHOTO_DB_ID ? PHOTO_DB_ID : GALLERY_DB_ID;
    }

    SetDirectory(parentId);
    m_parentId = parentId;

    // No SG & no devices uses special 'empty' screen
    if (!parent || (parentId == GALLERY_DB_ID && count == 1))
    {
        parent.clear();
        return false;
    }

    // Populate all subdirs
    foreach (ImagePtr im, dirs)
    {
        if (im)
            // Load sufficient thumbs from each dir as subsequent dirs may be empty
            LoadDirThumbs(*im, kMaxFolderThumbnails);
    }

    // Populate parent
    if (!PopulateFromCache(*parent, kMaxFolderThumbnails))
        PopulateThumbs(*parent, kMaxFolderThumbnails, files, dirs);

    // Dirs shown before images
    ImageList images = dirs + files;

    // Validate marked images
    if (!m_marked.isEmpty())
    {
        QSet<int> ids;
        foreach (ImagePtrK im, images)
            ids.insert(im->m_id);
        m_marked.intersect(ids);
    }

    // Parent is always first (for navigating up).
    images.prepend(parent);

    // Preserve current selection before view is destroyed
    ImagePtrK selected = GetSelected();
    int activeId = selected ? selected->m_id : 0;

    // Construct view
    Populate(images);

    // Reinstate selection, falling back to parent
    Select(activeId);

    return true;
}


void DirectoryView::LoadDirThumbs(ImageItem &parent, int thumbsNeeded, int level)
{
    // Use cached data, if available
    if (PopulateFromCache(parent, thumbsNeeded))
        return;

    // Load child images & dirs
    ImageList files, dirs;
    m_mgr.GetChildren(parent.m_id, files, dirs);

    PopulateThumbs(parent, thumbsNeeded, files, dirs, level);
}


void DirectoryView::PopulateThumbs(ImageItem &parent, int thumbsNeeded,
                                   const ImageList &files, const ImageList &dirs,
                                   int level)
{
    // Set parent stats
    parent.m_fileCount = files.size();
    parent.m_dirCount  = dirs.size();

    // Locate user assigned thumb amongst children, if defined
    ImagePtr userIm;
    if (parent.m_userThumbnail != 0)
    {
        foreach (ImagePtr im, files + dirs)
        {
            if (im && im->m_id == parent.m_userThumbnail)
            {
                userIm = im;
                break;
            }
        }
    }

    // Children to use as thumbnails
    ImageList thumbFiles, thumbDirs;

    if (!userIm)
    {
        // Construct multi-thumbnail from all children
        thumbFiles = files;
        thumbDirs  = dirs;
    }
    else if (userIm->IsFile())
    {
        thumbFiles.append(userIm);
        thumbsNeeded = 1;
    }
    else
        thumbDirs.append(userIm);

    // Fill parent thumbs from child files first
    // Whilst they're available fill as many as possible for cache
    for (int i = 0; i < qMin(kMaxFolderThumbnails, thumbFiles.size()); ++i)
    {
        parent.m_thumbNails.append(thumbFiles.at(i)->m_thumbNails.at(0));
        --thumbsNeeded;
    }

    // Only recurse if necessary
    if (thumbsNeeded > 0)
    {
        // Prevent lengthy/infinite recursion due to deep/cyclic folder
        // structures
        if (++level > 10)
            LOG(VB_GENERAL, LOG_NOTICE, LOC +
                "Directory thumbnails are more than 10 levels deep");
        else
        {
            // Recursively load subdir thumbs to try to get 1 thumb from each
            foreach (ImagePtr im, thumbDirs)
            {
                if (!im)
                    continue;

                // Load sufficient thumbs from each dir as subsequent dirs may
                // be empty
                LoadDirThumbs(*im, thumbsNeeded, level);

                if (!im->m_thumbNails.empty())
                {
                    // Add first thumbnail to parent thumb
                    parent.m_thumbNails.append(im->m_thumbNails.at(0));

                    // Quit when we have sufficient thumbs
                    if (--thumbsNeeded == 0)
                        break;
                }
            }

            // If insufficient dirs to supply 1 thumb per dir, use other dir
            // thumbs (indices 1-3) as well
            int i = 0;
            while (thumbsNeeded > 0 && ++i < kMaxFolderThumbnails)
            {
                foreach (ImagePtrK im, thumbDirs)
                {
                    if (i < im->m_thumbNails.size())
                    {
                        parent.m_thumbNails.append(im->m_thumbNails.at(i));
                        if (--thumbsNeeded == 0)
                            break;
                    }
                }
            }
        }
    }

    // Flag the cached entry with number of thumbs loaded. If future uses require
    // more, then the dir must be reloaded.
    // For user thumbs and dirs with insufficient child images, the cache is always valid
    int scanned = (userIm || thumbsNeeded > 0)
            ? kMaxFolderThumbnails
            : parent.m_thumbNails.size();

    // Cache result to optimize navigation
    Cache(parent, scanned);
}


void DirectoryView::Clear(bool /*resetParent*/)
{
    ClearMarked();
    ClearCache();
    FlatView::Clear();
}


void DirectoryView::MarkAll()
{
    // Any marking clears previous marks
    m_prevMarked.Clear();
    m_marked.Add(GetChildren());
}


void DirectoryView::Mark(int id, bool mark)
{
    if (mark)
    {
        // Any marking clears previous marks
        m_prevMarked.Clear();
        m_marked.Add(id);
    }
    else
    {
        m_prevMarked.remove(id);
        m_marked.remove(id);
    }
}


void DirectoryView::InvertMarked()
{
    // Any marking clears previous marks
    m_prevMarked.Clear();
    m_marked.Invert(GetChildren());
}


void DirectoryView::ClearMarked()
{
    m_marked.Clear();
    m_prevMarked.Clear();
}


void DirectoryView::SetDirectory(int newParent)
{
    if (m_marked.IsFor(newParent))
        // Directory hasn't changed
        return;

    // Markings are cleared on every dir change
    // Any current markings become previous markings
    // Only 1 set of previous markings are preserved
    if (m_prevMarked.IsFor(newParent))
    {
        // Returned to dir of previous markings: reinstate them
        m_marked = m_prevMarked;
        m_prevMarked.Clear();
        return;
    }

    if (!m_marked.isEmpty())
        // Preserve current markings
        m_prevMarked = m_marked;

    // Initialise current markings for new dir
    m_marked.Initialise(newParent);
}


MenuSubjects DirectoryView::GetMenuSubjects()
{
    // hiddenMarked is true if 1 or more marked items are hidden
    // unhiddenMarked is true if 1 or more marked items are not hidden
    bool hiddenMarked   = false;
    bool unhiddenMarked = false;
    foreach (int id, m_marked)
    {
        ImagePtrK im = m_images.value(id);
        if (!im)
            continue;

        if (im->m_isHidden)
            hiddenMarked = true;
        else
            unhiddenMarked = true;

        if (hiddenMarked && unhiddenMarked)
            break;
    }

    return MenuSubjects(GetSelected(), m_sequence.size() - 1,
                        m_marked,      m_prevMarked,
                        hiddenMarked,  unhiddenMarked);
}


bool DirectoryView::PopulateFromCache(ImageItem &dir, int required)
{
    DirCacheEntry cached(m_dirCache.value(dir.m_id));
    if (cached.m_dirCount == -1 || cached.m_thumbCount < required)
        return false;

    dir.m_fileCount  = cached.m_fileCount;
    dir.m_dirCount   = cached.m_dirCount;
    dir.m_thumbNails = cached.m_thumbs;

    LOG(VB_FILE, LOG_DEBUG, LOC + "Using cached " + cached.ToString(dir.m_id));
    return true;
}


void DirectoryView::Cache(ImageItemK &dir, int thumbCount)
{
    // Cache counts & thumbnails for each dir so that we don't need to reload its
    // children from Db each time it's displayed
    DirCacheEntry cacheEntry(dir.m_parentId, dir.m_dirCount, dir.m_fileCount,
                             dir.m_thumbNails, thumbCount);

    m_dirCache.insert(dir.m_id, cacheEntry);

    // Cache images used by dir thumbnails
    foreach (const ThumbPair &thumb, dir.m_thumbNails)
    {
        // Do not overwrite any existing image url nor parent.
        // Image url is cached when image is displayed as a child, but not as a
        // ancestor dir thumbnail
        // First cache attempt will be by parent. Subsequent attempts may be
        // by ancestor dirs.
        if (!m_fileCache.contains(thumb.first))
            FlatView::Cache(thumb.first, dir.m_id, "", thumb.second);
    }
    LOG(VB_FILE, LOG_DEBUG, LOC + "Caching " + cacheEntry.ToString(dir.m_id));
}


void DirectoryView::ClearCache()
{
    LOG(VB_FILE, LOG_DEBUG, LOC + "Cleared Dir cache");
    m_dirCache.clear();
    FlatView::ClearCache();
}


QStringList DirectoryView::RemoveImage(int id, bool deleted)
{
    QStringList urls;
    int dirId = id;

    if (deleted)
    {
        m_marked.remove(id);
        m_prevMarked.remove(id);
    }

    // If id is a file then start with its parent
    if (m_fileCache.contains(id))
    {
        // Clear file cache & start from its parent dir
        dirId = m_fileCache.value(id).m_parent;
        urls = FlatView::ClearImage(id, deleted);
    }

    // Clear ancestor dirs
    while (m_dirCache.contains(dirId))
    {
        LOG(VB_FILE, LOG_DEBUG, LOC + QString("Cleared %1 from dir cache").arg(dirId));
        DirCacheEntry dir = m_dirCache.take(dirId);
        dirId = dir.m_parent;
    }
    return urls;
}


bool TreeView::LoadFromDb(int parentId)
{
    m_parentId = parentId;

    // Load visible subtree of the parent
    // Ordered images of parent first, then breadth-first recursion of ordered dirs
    ImageList files;
    m_mgr.GetImageTree(m_parentId, files);

    // Load view
    Populate(files);

    return !files.isEmpty();
}