motiontrackermodel.cpp

/*
 * Copyright (c) 2023-2026 Meltytech, LLC
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */

#include "motiontrackermodel.h"

#include "Logger.h"
#include "mltcontroller.h"
#include "qmltypes/qmlfilter.h"
#include "shotcut_mlt_properties.h"

#include <Mlt.h>
#include <QUuid>

// This is hard-coded for now (minimum viable product).
static const int KEYFRAME_INTERVAL_FRAMES = 5;

class FindTrackersParser : public Mlt::Parser
{
private:
    MotionTrackerModel &m_model;

public:
    FindTrackersParser(MotionTrackerModel &model)
        : Mlt::Parser()
        , m_model{model}
    {}

    int on_start_filter(Mlt::Filter *filter)
    {
        if (QString::fromUtf8(filter->get("mlt_service")) == "opencv.tracker") {
            auto results = QString::fromLatin1(filter->get("results"));
            if (!results.isEmpty()) {
                auto name = QString::fromUtf8(filter->get(kTrackNameProperty));
                if (name.isEmpty()) {
                    name = m_model.nextName();
                    filter->set(kTrackNameProperty, name.toUtf8().constData());
                }
                auto key = m_model.add(name, results);
                if (!key.isEmpty()) {
                    filter->set(kUuidProperty, key.toUtf8().constData());
                }
            }
        }
        return 0;
    }
    int on_start_producer(Mlt::Producer *) { return 0; }
    int on_end_producer(Mlt::Producer *) { return 0; }
    int on_start_playlist(Mlt::Playlist *) { return 0; }
    int on_end_playlist(Mlt::Playlist *) { return 0; }
    int on_start_tractor(Mlt::Tractor *) { return 0; }
    int on_end_tractor(Mlt::Tractor *) { return 0; }
    int on_start_multitrack(Mlt::Multitrack *) { return 0; }
    int on_end_multitrack(Mlt::Multitrack *) { return 0; }
    int on_start_track() { return 0; }
    int on_end_track() { return 0; }
    int on_end_filter(Mlt::Filter *) { return 0; }
    int on_start_transition(Mlt::Transition *) { return 0; }
    int on_end_transition(Mlt::Transition *) { return 0; }
    int on_start_chain(Mlt::Chain *) { return 0; }
    int on_end_chain(Mlt::Chain *) { return 0; }
    int on_start_link(Mlt::Link *) { return 0; }
    int on_end_link(Mlt::Link *) { return 0; }
};

/*!
    \qmltype MotionTrackerModel
    \inqmlmodule org.shotcut.qml
    \brief A list model of motion tracker entries attached to the current producer.

    \c MotionTrackerModel is available as the \c motionTrackerModel context property
    in the Filters panel. Each row represents one stored motion tracker (a named bounding-box
    trajectory recorded against the clip).
*/

/*!
    \qmlproperty string MotionTrackerModel::nameProperty
    \brief The MLT property name used to store the tracker's display name on a filter
    (value: \c "shotcut:motionTracker.name"). CONSTANT.
*/

/*!
    \qmlproperty string MotionTrackerModel::operationProperty
    \brief The MLT property name used to store the tracker's link operation on a filter
    (value: \c "shotcut:motionTracker.operation"). CONSTANT.
*/

MotionTrackerModel::MotionTrackerModel(QObject *parent)
    : QAbstractListModel(parent)
{
    m_data[""] = {""}; // To show nothing in a combo
}

void MotionTrackerModel::load(Mlt::Producer *producer, bool reset)
{
    if (!producer)
        producer = MLT.producer();
    if (reset) {
        beginResetModel();
        m_data.clear();
        beginInsertRows(QModelIndex(), 0, 0);
        m_data[""] = {""};
        endInsertRows();
    }
    if (producer && producer->is_valid()) {
        FindTrackersParser(*this).start(*producer);
        Mlt::Properties retainList((mlt_properties) producer->get_data("xml_retain"));
        if (retainList.is_valid()) {
            Mlt::Playlist playlist((mlt_playlist) retainList.get_data(kPlaylistTrackId));
            if (playlist.is_valid() && playlist.type() == mlt_service_playlist_type) {
                FindTrackersParser(*this).start(playlist);
            }
        }
    }
    if (reset)
        endResetModel();
}

QString MotionTrackerModel::add(const QString &name, const QString &data)
{
    auto key = QUuid::createUuid().toString();
    if (!m_data.contains(key)) {
        auto row = rowCount();
        beginInsertRows(QModelIndex(), row, row);
        m_data[key] = {name, data, KEYFRAME_INTERVAL_FRAMES};
        LOG_DEBUG() << key << m_data[key].name;
        endInsertRows();
        return key;
    }
    return QString();
}

void MotionTrackerModel::updateData(const QString &key, const QString &data)
{
    auto keys = m_data.keys();
    auto row = keys.indexOf(key);
    if (row >= 0) {
        m_data[key].trackingData = data;
        auto i = createIndex(row, 0);
        emit dataChanged(i, i, {TrackingDataRole});
    }
}

void MotionTrackerModel::remove(const QString &key)
{
    if (m_data.contains(key)) {
        auto i = m_data.constBegin();
        for (int row = 0; i != m_data.constEnd(); ++i, ++row) {
            if (i.key() == key) {
                beginRemoveRows(QModelIndex(), row, row);
                m_data.remove(key);
                endInsertRows();
                break;
            }
        }
    }
}

void MotionTrackerModel::removeFromService(Mlt::Service *service)
{
    // look for an attached filter with mlt_service = opencv.tracker
    if (service && service->is_valid()) {
        auto producer = Mlt::Producer(*service).parent();
        for (int i = 0; i < producer.filter_count(); i++) {
            auto filter = producer.filter(i);
            if (filter && filter->is_valid()) {
                if (QString::fromUtf8(filter->get("mlt_service")) == "opencv.tracker") {
                    auto key = keyForFilter(filter);
                    if (!key.isEmpty())
                        remove(key);
                }
            }
        }
    }
}

/*!
    \qmlmethod void MotionTrackerModel::setName(Filter filter, string name)
    \brief Sets the display \a name for the tracker linked to \a filter.
*/

void MotionTrackerModel::setName(QmlFilter *filter, const QString &name)
{
    if (filter && filter->service().is_valid()) {
        auto key = keyForFilter(&filter->service());
        if (!key.isEmpty() && m_data.contains(key)) {
            m_data[key].name = name;
        }
    }
}

/*!
    \qmlmethod string MotionTrackerModel::nextName()
    \brief Returns an auto-generated unique name for a new tracker (e.g. \c "Tracker 2").
*/

QString MotionTrackerModel::nextName() const
{
    return tr("Tracker %1").arg(rowCount());
}

QString MotionTrackerModel::keyForRow(int row) const
{
    QString key;
    auto keys = m_data.keys();
    if (row >= 0 && row < keys.size()) {
        key = keys.at(row);
    }
    return key;
}

QString MotionTrackerModel::keyForFilter(Mlt::Service *service)
{
    QString key;
    if (service && service->is_valid())
        key = service->get(kUuidProperty);
    return key;
}

/*!
    \qmlmethod void MotionTrackerModel::reset(Filter filter, string property, int row)
    \brief Clears the keyframes for \a property on \a filter that were written by the tracker
    at model row \a row.
*/

void MotionTrackerModel::reset(QmlFilter *filter, const QString &property, int row)
{
    auto key = keyForRow(row);
    if (!key.isEmpty() && filter && filter->service().is_valid() && !property.isEmpty()) {
        auto data = trackingData(key);

        if (!data.isEmpty()) {
            // Use a shotcut property to backup current values
            if (filter->get(kBackupProperty).isEmpty()) {
                filter->set(kBackupProperty, filter->get(property));
            } else {
                filter->set(property, filter->get(kBackupProperty));
            }
        }
    }
}

/*!
    \qmlmethod list<rect> MotionTrackerModel::trackingData(int row)
    \brief Returns the list of bounding-box rectangles recorded by the tracker at \a row,
    one entry per keyframe interval frame.
*/

QList<MotionTrackerModel::TrackingItem> MotionTrackerModel::trackingData(const QString &key) const
{
    QList<TrackingItem> result;
    auto s = m_data.value(key, {}).trackingData;
    auto l = s.split(';');
    Mlt::Properties props;
    auto consumer = MLT.consumer();

    for (const auto &i : l) {
        auto pair = i.split("~=");
        if (pair.size() == 2) {
            // The keyframe time is serialized either as a frame number ("5") or
            // as a clock value ("00:00:00.167"), depending on the time format
            // MLT used when the project was written (animated properties are
            // saved as time so they adapt to a frame-rate change). time_to_frames()
            // parses both forms to the correct frame using the project frame rate.
            int frame = consumer ? consumer->time_to_frames(pair.at(0).toUtf8().constData())
                                 : pair.at(0).toInt();
            props.set("", pair.at(1).toLatin1().constData());
            auto rect = props.get_rect("");
            result << TrackingItem{frame, QRectF(rect.x, rect.y, rect.w, rect.h)};
        }
    }
    return result;
}

QList<QRectF> MotionTrackerModel::trackingData(int row) const
{
    auto key = keyForRow(row);
    QList<QRectF> result;
    if (!key.isEmpty() && m_data.contains(key)) {
        for (const auto &a : trackingData(key)) {
            result << a.rect;
        }
    }
    return result;
}

/*!
    \qmlmethod int MotionTrackerModel::keyframeIntervalFrames(int row)
    \brief Returns the keyframe interval in frames for the tracker at \a row.
*/

int MotionTrackerModel::keyframeIntervalFrames(int row) const
{
    auto key = keyForRow(row);
    if (!key.isEmpty() && m_data.contains(key))
        return m_data.value(key).intervalFrames;
    return KEYFRAME_INTERVAL_FRAMES;
}

int MotionTrackerModel::rowCount(const QModelIndex &parent) const
{
    // For list models only the root node (an invalid parent) should return the list's size. For all
    // other (valid) parents, rowCount() should return 0 so that it does not become a tree model.
    if (parent.isValid())
        return 0;

    return m_data.size();
}

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

    auto key = keyForRow(index.row());
    if (!key.isEmpty()) {
        switch (role) {
        case Qt::DisplayRole:
            return m_data.value(key).name;
        case TrackingDataRole:
            return m_data.value(key).trackingData;
        default:
            break;
        }
    }
    return QVariant();
}

bool MotionTrackerModel::setData(const QModelIndex &index, const QVariant &value, int role)
{
    if (data(index, role) != value) {
        auto key = index.data(Qt::UserRole).toString();
        if (m_data.contains(key)) {
            switch (role) {
            case Qt::DisplayRole:
                m_data[key].name = value.toString();
                emit dataChanged(index, index, {role});
                break;
            case TrackingDataRole:
                m_data[key].trackingData = value.toString();
                emit dataChanged(index, index, {role});
                break;
            default:
                break;
            }
            return true;
        }
    }
    return false;
}

Qt::ItemFlags MotionTrackerModel::flags(const QModelIndex &index) const
{
    if (!index.isValid())
        return Qt::NoItemFlags;

    return QAbstractItemModel::flags(index) | Qt::ItemIsEditable;
}

/*!
    \qmlmethod void MotionTrackerModel::undo(Filter filter, string propertyName)
    \brief Static helper that removes motion-tracker–written keyframes for \a propertyName
    on \a filter, typically called before re-applying a tracker.
*/

void MotionTrackerModel::undo(QmlFilter *filter, const QString &propertyName)
{
    if (filter && !propertyName.isEmpty()) {
        filter->set(propertyName, filter->get(kBackupProperty));
        filter->resetProperty(kBackupProperty);
    }
}