Add live location tracking model

This can either watch a single live location beacon or all of those in
a given room.

src/models/livelocationsmodel.h

@@ -0,0 +1,67 @@
+// SPDX-FileCopyrightText: 2023 Tobias Fella <tobias.fella@kde.org>
+// SPDX-FileCopyrightText: 2023 Volker Krause <vkrause@kde.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "neochatroom.h"
+
+#include <QAbstractListModel>
+#include <QPointer>
+
+namespace Quotient
+{
+class RoomMessageEvent;
+}
+
+struct LiveLocationData {
+    QString eventId;
+    QString senderId;
+    QJsonObject beaconInfo;
+    QJsonObject beacon;
+};
+bool operator<(const LiveLocationData &lhs, const LiveLocationData &rhs);
+
+/** Accumulates live location beacon events in a given room
+ *  and provides the last known state for one or more live location beacons.
+ */
+class LiveLocationsModel : public QAbstractListModel
+{
+    Q_OBJECT
+    Q_PROPERTY(NeoChatRoom *room MEMBER m_room NOTIFY roomChanged)
+    /** The event id of the beacon start event, ie. the one all suspequent
+     *  events use to relate to the same beacon.
+     *  If this is set only this specific beacon will be coverd by this model,
+     *  if it is empty, all beacons in the room will be covered.
+     */
+    Q_PROPERTY(QString eventId MEMBER m_eventId NOTIFY eventIdChanged)
+
+public:
+    explicit LiveLocationsModel(QObject *parent = nullptr);
+
+    enum Roles {
+        LatitudeRole, /**< Latest latitude of a live locaction beacon. */
+        LongitudeRole, /**< Latest longitude of a live locaction beacon. */
+        AssetRole, /**< Type of location event, e.g. self pin of the user location. */
+        AuthorRole, /**< The author of the event. */
+        IsLiveRole, /**< Boolean that indicates whether a live location beacon is still live. */
+    };
+    Q_ENUM(Roles)
+
+    int rowCount(const QModelIndex &parent = {}) const override;
+    QVariant data(const QModelIndex &index, int roleName) const override;
+    QHash<int, QByteArray> roleNames() const override;
+
+Q_SIGNALS:
+    void roomChanged();
+    void eventIdChanged();
+
+private:
+    void addEvent(const Quotient::RoomEvent *event);
+    void updateLocationData(LiveLocationData &&data);
+
+    QPointer<NeoChatRoom> m_room;
+    QString m_eventId;
+
+    QList<LiveLocationData> m_locations;
+};