🏡 index : quine-global-labs/plasma-desktop.git

/***************************************************************************
 *   Copyright (C) 2014 by Eike Hein <hein@kde.org>                   *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA .        *
 ***************************************************************************/

#include "positioner.h"
#include "foldermodel.h"

#include <QDebug>
#include <QTimer>

#include <cstdlib>

Positioner::Positioner(QObject *parent): QAbstractItemModel(parent)
, m_enabled(false)
, m_folderModel(0)
, m_perStripe(0)
, m_lastRow(-1)
, m_ignoreNextTransaction(false)
, m_pendingPositions(false)
, m_updatePositionsTimer(new QTimer(this))
{
    m_updatePositionsTimer->setSingleShot(true);
    m_updatePositionsTimer->setInterval(0);
    connect(m_updatePositionsTimer, SIGNAL(timeout()), this, SLOT(updatePositions()));
}

Positioner::~Positioner()
{
}

bool Positioner::enabled() const
{
    return m_enabled;
}

void Positioner::setEnabled(bool enabled)
{
    if (m_enabled != enabled) {
        m_enabled = enabled;

        beginResetModel();

        if (enabled && m_folderModel) {
            initMaps();
        }

        endResetModel();

        emit enabledChanged();

        if (!enabled) {
            m_updatePositionsTimer->start();
        }
    }
}

FolderModel* Positioner::folderModel() const
{
    return m_folderModel;
}

void Positioner::setFolderModel(QObject *folderModel)
{
    if (m_folderModel != folderModel) {
        beginResetModel();

        if (m_folderModel) {
            disconnectSignals(m_folderModel);
        }

        m_folderModel = qobject_cast<FolderModel *>(folderModel);
        connect(m_folderModel, SIGNAL(urlChanged()), this, SLOT(reset()), Qt::UniqueConnection);

        if (m_folderModel) {
            connectSignals(m_folderModel);

            if (m_enabled) {
                initMaps();
            }
        }

        endResetModel();

        emit folderModelChanged();
    }
}

int Positioner::perStripe() const
{
    return m_perStripe;
}

void Positioner::setPerStripe(int perStripe)
{
    if (m_perStripe != perStripe) {
        m_perStripe = perStripe;

        if (m_enabled && perStripe > 0 && !m_proxyToSource.isEmpty()) {
            applyPositions();
        }
    }
}

QStringList Positioner::positions() const
{
    return m_positions;
}

void Positioner::setPositions(QStringList positions)
{
    if (m_positions != positions) {
        m_positions = positions;

        emit positionsChanged();

        if (!m_proxyToSource.isEmpty()) {
            applyPositions();
        } else if (m_positions.size() >= 5) {
            m_pendingPositions = true;
        }
    }
}

int Positioner::map(int row) const
{
    if (m_enabled && m_folderModel) {
        if (m_proxyToSource.contains(row)) {
            return m_proxyToSource.value(row);
        } else {
            return -1;
        }
    }

    return row;
}

int Positioner::nearestItem(int currentIndex, Qt::ArrowType direction)
{
    if (!m_enabled || currentIndex >= rowCount()) {
        return -1;
    }

    if (currentIndex < 0) {
        return firstRow();
    }

    int hDirection = 0;
    int vDirection = 0;

    switch (direction) {
        case Qt::LeftArrow:
            hDirection = -1;
            break;
        case Qt::RightArrow:
            hDirection = 1;
            break;
        case Qt::UpArrow:
            vDirection = -1;
            break;
        case Qt::DownArrow:
            vDirection = 1;
            break;
        default:
            return -1;
    }

    QList<int> rows(m_proxyToSource.keys());
    qSort(rows);

    int nearestItem = -1;
    const QPoint currentPos(currentIndex % m_perStripe, currentIndex / m_perStripe);
    int lastDistance = -1;
    int distance = 0;

    foreach (int row, rows) {
        const QPoint pos(row % m_perStripe, row / m_perStripe);

        if (row == currentIndex) {
            continue;
        }

        if (hDirection == 0) {
            if (vDirection * pos.y() > vDirection * currentPos.y()) {
                distance = (pos - currentPos).manhattanLength();

                if (nearestItem == -1 || distance < lastDistance
                    || (distance == lastDistance && pos.x() == currentPos.x())) {
                    nearestItem = row;
                    lastDistance = distance;
                }
            }
        } else if (vDirection == 0) {
            if (hDirection * pos.x() > hDirection * currentPos.x()) {
                distance = (pos - currentPos).manhattanLength();

                if (nearestItem == -1 || distance < lastDistance
                    || (distance == lastDistance && pos.y() == currentPos.y())) {
                    nearestItem = row;
                    lastDistance = distance;
                }
            }
        }
    }

    return nearestItem;
}

bool Positioner::isBlank(int row) const
{
    if (!m_enabled && m_folderModel) {
        return m_folderModel->isBlank(row);
    }

    if (m_proxyToSource.contains(row) && !m_folderModel->isBlank(m_proxyToSource.value(row))) {
        return false;
    }

    return true;
}

int Positioner::indexForUrl(const QUrl &url) const
{
    if (!m_folderModel) {
        return -1;
    }

    const QString &name = url.fileName();

    int sourceIndex = -1;

    // TODO Optimize.
    for (int i = 0; i < m_folderModel->rowCount(); ++i) {
        if (m_folderModel->data(m_folderModel->index(i, 0), FolderModel::FileNameRole).toString() == name) {
            sourceIndex = i;

            break;
        }
    }

    if (m_sourceToProxy.contains(sourceIndex)) {
        return m_sourceToProxy.value(sourceIndex);
    }

    return -1;
}

void Positioner::setRangeSelected(int anchor, int to)
{
    if (!m_folderModel) {
        return;
    }

    if (m_enabled) {
        QVariantList indices;

        for (int i = qMin(anchor, to); i <= qMax(anchor, to); ++i) {
            if (m_proxyToSource.contains(i)) {
                indices.append(m_proxyToSource.value(i));
            }
        }

        if (indices.count()) {
            m_folderModel->updateSelection(indices, false);
        }
    } else {
        m_folderModel->setRangeSelected(anchor, to);
    }
}

QHash< int, QByteArray > Positioner::roleNames() const
{
    return FolderModel::staticRoleNames();
}

QModelIndex Positioner::index(int row, int column, const QModelIndex &parent) const
{
    if (parent.isValid()) {
        return QModelIndex();
    }

    return createIndex(row, column);
}

QModelIndex Positioner::parent(const QModelIndex &index) const
{
    if (m_folderModel) {
        m_folderModel->parent(index);
    }

    return QModelIndex();
}

QVariant Positioner::data(const QModelIndex &index, int role) const
{
    if (!index.isValid()) {
        return QVariant();
    }

    if (m_folderModel) {
        if (m_enabled) {
            if (m_proxyToSource.contains(index.row())) {
                return m_folderModel->data(m_folderModel->index(m_proxyToSource.value(index.row()), 0), role);
            } else if (role == FolderModel::BlankRole) {
                return true;
            }
        } else {
            return m_folderModel->data(m_folderModel->index(index.row(), 0), role);
        }
    }

    return QVariant();
}

int Positioner::rowCount(const QModelIndex& parent) const
{
    if (m_folderModel) {
        if (m_enabled) {
            return lastRow() + 1;
        } else {
            return m_folderModel->rowCount(parent);
        }
    }

    return 0;
}

int Positioner::columnCount(const QModelIndex& parent) const
{
    Q_UNUSED(parent)

    if (m_folderModel) {
        return 1;
    }

    return 0;
}

void Positioner::reset()
{
    beginResetModel();

    initMaps();

    endResetModel();

    m_positions = QStringList();
    emit positionsChanged();
}

void Positioner::move(const QVariantList &moves) {
    QVector<int> fromIndices;
    QVector<int> toIndices;
    QVector<int> sourceRows;

    for (int i = 0; i < moves.count(); ++i) {
        const int isFrom = (i % 2 == 0);
        const int v = moves[i].toInt();

        if (isFrom) {
            if (m_proxyToSource.contains(v)) {
                sourceRows.append(m_proxyToSource.value(v));
            } else {
                sourceRows.append(-1);
            }
        }

        (isFrom ? fromIndices : toIndices).append(v);
    }

    const int oldCount = rowCount();

    for (int i = 0; i < fromIndices.count(); ++i)
    {
        const int from = fromIndices[i];
        int to = toIndices[i];
        const int sourceRow = sourceRows[i];

        if (sourceRow == -1 || from == to) {
            continue;
        }

        if (to == -1) {
            to = firstFreeRow();

            if (to == -1) {
                to = lastRow() + 1;
            }
        }

        if (!fromIndices.contains(to) && !isBlank(to)) {
            continue;
        }

        toIndices[i] = to;

        if (!toIndices.contains(from)) {
            m_proxyToSource.remove(from);
        }

        updateMaps(to, sourceRow);

        const QModelIndex &fromIdx = index(from, 0);
        emit dataChanged(fromIdx, fromIdx);

        if (to < oldCount) {
            const QModelIndex &toIdx = index(to, 0);
            emit dataChanged(toIdx, toIdx);
        }
    }

    const int newCount = rowCount();

    if (newCount > oldCount) {
        beginInsertRows(QModelIndex(), oldCount, newCount - 1);
        endInsertRows();
    }

    if (newCount < oldCount) {
        beginRemoveRows(QModelIndex(), newCount, oldCount - 1);
        endRemoveRows();
    }

    m_updatePositionsTimer->start();
}

void Positioner::updatePositions()
{
    QStringList positions;

    if (m_enabled && !m_proxyToSource.isEmpty() && m_perStripe > 0) {
        positions.append(QString::number((1 + ((rowCount() - 1) / m_perStripe))));
        positions.append(QString::number(m_perStripe));

        QHashIterator<int, int> it(m_proxyToSource);

        while (it.hasNext()) {
            it.next();

            const QString &name = m_folderModel->data(m_folderModel->index(it.value(), 0),
                FolderModel::UrlRole).toString();

            if (name.isEmpty()) {
                qDebug() << this << it.value() << "Source model doesn't know this index!";

                return;
            }

            positions.append(name);
            positions.append(QString::number(qMax(0, it.key() / m_perStripe)));
            positions.append(QString::number(qMax(0, it.key() % m_perStripe)));
        }
    }

    if (positions != m_positions) {
        m_positions = positions;

        emit positionsChanged();
    }
}

void Positioner::sourceDataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight,
    const QVector<int>& roles)
{
    if (m_enabled) {
        int start = topLeft.row();
        int end = bottomRight.row();

        for (int i = start; i <= end; ++i) {
            if (m_sourceToProxy.contains(i)) {
                const QModelIndex &idx = index(m_sourceToProxy.value(i), 0);

                emit dataChanged(idx, idx);
            }
        }
    } else {
        emit dataChanged(topLeft, bottomRight, roles);
    }
}

void Positioner::sourceModelAboutToBeReset()
{
    emit beginResetModel();
}

void Positioner::sourceModelReset()
{
    if (m_enabled) {
        initMaps();
    }

    emit endResetModel();
}

void Positioner::sourceRowsAboutToBeInserted(const QModelIndex &parent, int start, int end)
{
    if (m_enabled) {
        if (m_proxyToSource.isEmpty()) {
            if (!m_pendingPositions) {
                emit beginInsertRows(parent, start, end);

                initMaps(end + 1);
            }

            return;
        }

        int free = -1;
        int rest = -1;

        for (int i = start; i <= end; ++i) {
            free = firstFreeRow();

            if (free != -1) {
                updateMaps(free, i);
                m_pendingChanges << createIndex(free, 0);
            } else {
                rest = i;
                break;
            }
        }

        if (rest != -1) {
            int firstNew = lastRow() + 1;
            int remainder = (end - rest);

            beginInsertRows(parent, firstNew, firstNew + remainder);

            for (int i = 0; i <= remainder; ++i) {
                updateMaps(firstNew + i, rest + i);
            }
        } else {
            m_ignoreNextTransaction = true;
        }
    } else {
        emit beginInsertRows(parent, start, end);
    }
}

void Positioner::sourceRowsAboutToBeMoved(const QModelIndex &sourceParent, int sourceStart,
    int sourceEnd, const QModelIndex& destinationParent, int destinationRow)
{
    emit beginMoveRows(sourceParent, sourceStart, sourceEnd, destinationParent, destinationRow);
}

void Positioner::sourceRowsAboutToBeRemoved(const QModelIndex &parent, int first, int last)
{
    if (m_enabled) {
        int oldLast = lastRow();

        for (int i = first; i <= last; ++i) {
            int proxyRow = m_sourceToProxy.take(i);
            m_proxyToSource.remove(proxyRow);
            m_pendingChanges << createIndex(proxyRow, 0);
        }

        QHash<int, int> newProxyToSource;
        QHash<int, int> newSourceToProxy;
        QHashIterator<int, int> it(m_sourceToProxy);
        int delta = std::abs(first - last) + 1;

        while (it.hasNext()) {
            it.next();

            if (it.key() > last) {
                newProxyToSource.insert(it.value(), it.key() - delta);
                newSourceToProxy.insert(it.key() - delta, it.value());
            } else {
                newProxyToSource.insert(it.value(), it.key());
                newSourceToProxy.insert(it.key(), it.value());
            }
        }

        m_proxyToSource = newProxyToSource;
        m_sourceToProxy = newSourceToProxy;

        m_lastRow = -1;
        int newLast = lastRow();

        if (oldLast > newLast) {
            int diff = oldLast - newLast;
            beginRemoveRows(QModelIndex(), ((oldLast - diff) + 1), oldLast);
        } else {
            m_ignoreNextTransaction = true;
        }
    } else {
        emit beginRemoveRows(parent, first, last);
    }
}

void Positioner::sourceLayoutAboutToBeChanged(const QList<QPersistentModelIndex> &parents,
    QAbstractItemModel::LayoutChangeHint hint)
{
    Q_UNUSED(parents)

    emit layoutAboutToBeChanged(QList<QPersistentModelIndex>(), hint);
}

void Positioner::sourceRowsInserted(const QModelIndex &parent, int first, int last)
{
    Q_UNUSED(parent)
    Q_UNUSED(first)
    Q_UNUSED(last)

    if (!m_ignoreNextTransaction) {
        if (!m_pendingPositions) {
            emit endInsertRows();
        } else {
            applyPositions();
        }
    } else {
        m_ignoreNextTransaction = false;
    }

    flushPendingChanges();

    m_updatePositionsTimer->start();
}

void Positioner::sourceRowsMoved(const QModelIndex &sourceParent, int sourceStart,
    int sourceEnd, const QModelIndex &destinationParent, int destinationRow)
{
    Q_UNUSED(sourceParent)
    Q_UNUSED(sourceStart)
    Q_UNUSED(sourceEnd)
    Q_UNUSED(destinationParent)
    Q_UNUSED(destinationRow)

    emit endMoveRows();
}

void Positioner::sourceRowsRemoved(const QModelIndex &parent, int first, int last)
{
    Q_UNUSED(parent)
    Q_UNUSED(first)
    Q_UNUSED(last)

    if (!m_ignoreNextTransaction) {
        emit endRemoveRows();
    } else {
        m_ignoreNextTransaction = false;
    }

    flushPendingChanges();

    m_updatePositionsTimer->start();
}

void Positioner::sourceLayoutChanged(const QList<QPersistentModelIndex>& parents,
    QAbstractItemModel::LayoutChangeHint hint)
{
    Q_UNUSED(parents)

    if (m_enabled) {
        initMaps();
    }

    emit layoutChanged(QList<QPersistentModelIndex>(), hint);
}

void Positioner::initMaps(int size)
{
    m_proxyToSource.clear();
    m_sourceToProxy.clear();

    if (size == -1) {
        size = m_folderModel->rowCount();
    }

    if (!size) {
        return;
    }

    for (int i = 0; i < size; ++i) {
        updateMaps(i, i);
    }
}

void Positioner::updateMaps(int proxyIndex, int sourceIndex)
{
    m_proxyToSource.insert(proxyIndex, sourceIndex);
    m_sourceToProxy.insert(sourceIndex, proxyIndex);
    m_lastRow = -1;
}

int Positioner::firstRow() const
{
    if (!m_proxyToSource.isEmpty()) {
        QList<int> keys(m_proxyToSource.keys());
        qSort(keys);

        return keys.first();
    }

    return -1;
}

int Positioner::lastRow() const
{
    if (!m_proxyToSource.isEmpty()) {
        if (m_lastRow != -1) {
            return m_lastRow;
        } else {
            QList<int> keys(m_proxyToSource.keys());
            qSort(keys);
            return keys.last();
        }
    }

    return 0;
}

int Positioner::firstFreeRow() const
{
    if (!m_proxyToSource.isEmpty()) {
        int last = lastRow();

        for (int i = 0; i <= last; ++i) {
            if (!m_proxyToSource.contains(i)) {
                return i;
            }
        }
    }

    return -1;
}

void Positioner::applyPositions()
{
    if (m_positions.size() < 5) {
        return;
    }

    beginResetModel();

    m_proxyToSource.clear();
    m_sourceToProxy.clear();

    const QStringList &positions = m_positions.mid(2);

    if (positions.count() % 3 != 0) {
        return;
    }

    QHash<QString, int> sourceIndices;

    for (int i = 0; i < m_folderModel->rowCount(); ++i) {
        sourceIndices.insert(m_folderModel->data(m_folderModel->index(i, 0),
            FolderModel::UrlRole).toString(), i);
    }

    QString name;
    int stripe = -1;
    int pos = -1;
    int sourceIndex = -1;
    int index = -1;
    bool ok = false;
    int offset = 0;

    // Restore positions for items that still fit.
    for (int i = 0; i < positions.count() / 3; ++i) {
        offset = i * 3;
        pos = positions.at(offset + 2).toInt(&ok);
        if (!ok) { return; }

        if (pos <= m_perStripe) {
            name = positions.at(offset);
            stripe = positions.at(offset + 1).toInt(&ok);
            if (!ok) { return; }

            if (!sourceIndices.contains(name)) {
                continue;
            } else {
                sourceIndex = sourceIndices.value(name);
            }

            index = (stripe * m_perStripe) + pos;

            if (m_proxyToSource.contains(index)) {
                continue;
            }

            updateMaps(index, sourceIndex);
            sourceIndices.remove(name);
        }
    }

    // Find new positions for items that didn't fit.
    for (int i = 0; i < positions.count() / 3; ++i) {
        offset = i * 3;
        pos = positions.at(offset + 2).toInt(&ok);
        if (!ok) { return; }

        if (pos > m_perStripe) {
            name = positions.at(offset);

            if (!sourceIndices.contains(name)) {
                continue;
            } else {
                sourceIndex = sourceIndices.take(name);
            }

            index = firstFreeRow();

            if (index == -1) {
                index = lastRow() + 1;
            }

            updateMaps(index, sourceIndex);
        }
    }

    QHashIterator<QString, int> it(sourceIndices);

    // Find positions for new source items we don't have records for.
    while (it.hasNext()) {
        it.next();

        index = firstFreeRow();

        if (index == -1) {
            index = lastRow() + 1;
        }

        updateMaps(index, it.value());
    }

    endResetModel();

    m_pendingPositions = false;

    m_updatePositionsTimer->start();
}

void Positioner::flushPendingChanges()
{
    if (m_pendingChanges.isEmpty()) {
        return;
    }

    int last = lastRow();

    foreach (const QModelIndex &idx, m_pendingChanges) {
        if (idx.row() <= last) {
            emit dataChanged(idx, idx);
        }
    }

    m_pendingChanges.clear();
}

void Positioner::connectSignals(FolderModel* model)
{
    connect(model, SIGNAL(dataChanged(QModelIndex,QModelIndex,QVector<int>)),
            this, SLOT(sourceDataChanged(QModelIndex,QModelIndex,QVector<int>)),
            Qt::UniqueConnection);
    connect(model, SIGNAL(rowsAboutToBeInserted(QModelIndex,int,int)),
            this, SLOT(sourceRowsAboutToBeInserted(QModelIndex,int,int)),
            Qt::UniqueConnection);
    connect(model, SIGNAL(rowsAboutToBeMoved(QModelIndex,int,int,QModelIndex,int)),
            this, SLOT(sourceRowsAboutToBeMoved(QModelIndex,int,int,QModelIndex,int)),
            Qt::UniqueConnection);
    connect(model, SIGNAL(rowsAboutToBeRemoved(QModelIndex,int,int)),
            this, SLOT(sourceRowsAboutToBeRemoved(QModelIndex,int,int)),
            Qt::UniqueConnection);
    connect(model, SIGNAL(layoutAboutToBeChanged(QList<QPersistentModelIndex>,QAbstractItemModel::LayoutChangeHint)),
            this, SLOT(sourceLayoutAboutToBeChanged(QList<QPersistentModelIndex>,QAbstractItemModel::LayoutChangeHint)),
            Qt::UniqueConnection);
    connect(model, SIGNAL(rowsInserted(QModelIndex,int,int)),
            this, SLOT(sourceRowsInserted(QModelIndex,int,int)),
            Qt::UniqueConnection);
    connect(model, SIGNAL(rowsMoved(QModelIndex,int,int,QModelIndex,int)),
            this, SLOT(sourceRowsMoved(QModelIndex,int,int,QModelIndex,int)),
            Qt::UniqueConnection);
    connect(model, SIGNAL(rowsRemoved(QModelIndex,int,int)),
            this, SLOT(sourceRowsRemoved(QModelIndex,int,int)),
            Qt::UniqueConnection);
    connect(model, SIGNAL(layoutChanged(QList<QPersistentModelIndex>,QAbstractItemModel::LayoutChangeHint)),
            this, SLOT(sourceLayoutChanged(QList<QPersistentModelIndex>,QAbstractItemModel::LayoutChangeHint)),
            Qt::UniqueConnection);
}

void Positioner::disconnectSignals(FolderModel* model)
{
    disconnect(model, SIGNAL(dataChanged(QModelIndex,QModelIndex,QVector<int>)),
            this, SLOT(sourceDataChanged(QModelIndex,QModelIndex,QVector<int>)));
    disconnect(model, SIGNAL(rowsAboutToBeInserted(QModelIndex,int,int)),
            this, SLOT(sourceRowsAboutToBeInserted(QModelIndex,int,int)));
    disconnect(model, SIGNAL(rowsAboutToBeMoved(QModelIndex,int,int,QModelIndex,int)),
            this, SLOT(sourceRowsAboutToBeMoved(QModelIndex,int,int,QModelIndex,int)));
    disconnect(model, SIGNAL(rowsAboutToBeRemoved(QModelIndex,int,int)),
            this, SLOT(sourceRowsAboutToBeRemoved(QModelIndex,int,int)));
    disconnect(model, SIGNAL(layoutAboutToBeChanged(QList<QPersistentModelIndex>,QAbstractItemModel::LayoutChangeHint)),
            this, SLOT(sourceLayoutAboutToBeChanged(QList<QPersistentModelIndex>,QAbstractItemModel::LayoutChangeHint)));
    disconnect(model, SIGNAL(rowsInserted(QModelIndex,int,int)),
            this, SLOT(sourceRowsInserted(QModelIndex,int,int)));
    disconnect(model, SIGNAL(rowsMoved(QModelIndex,int,int,QModelIndex,int)),
            this, SLOT(sourceRowsMoved(QModelIndex,int,int,QModelIndex,int)));
    disconnect(model, SIGNAL(rowsRemoved(QModelIndex,int,int)),
            this, SLOT(sourceRowsRemoved(QModelIndex,int,int)));
    disconnect(model, SIGNAL(layoutChanged(QList<QPersistentModelIndex>,QAbstractItemModel::LayoutChangeHint)),
            this, SLOT(sourceLayoutChanged(QList<QPersistentModelIndex>,QAbstractItemModel::LayoutChangeHint)));
}