Loading and End of Timeline Delegates

Add delegate for showing the user a loading indicator and for the beginning of the timeline.

BUG: 455045
BUG: 465285

src/models/messageeventmodel.cpp

@@ -389,13 +389,7 @@ int MessageEventModel::rowCount(const QModelIndex &parent) const
         return 0;
     }
 
-    const auto firstIt = m_currentRoom->messageEvents().crbegin();
-    if (firstIt != m_currentRoom->messageEvents().crend()) {
-        const auto &firstEvt = **firstIt;
-        return m_currentRoom->timelineSize() + (lastReadEventId != firstEvt.id() ? 1 : 0);
-    } else {
-        return m_currentRoom->timelineSize();
-    }
+    return int(m_currentRoom->pendingEvents().size()) + m_currentRoom->timelineSize() + (m_lastReadEventIndex.isValid() ? 1 : 0);
 }
 
 bool MessageEventModel::canFetchMore(const QModelIndex &parent) const
@@ -422,7 +416,7 @@ QVariant MessageEventModel::data(const QModelIndex &idx, int role) const
     }
     const auto row = idx.row();
 
-    if (!m_currentRoom || row < 0 || row >= int(m_currentRoom->pendingEvents().size()) + m_currentRoom->timelineSize()) {
+    if (!m_currentRoom || row < 0 || row >= rowCount()) {
         return {};
     };
 
@@ -465,7 +459,6 @@ QVariant MessageEventModel::data(const QModelIndex &idx, int role) const
             return (reason.isEmpty()) ? i18n("<i>[This message was deleted]</i>")
                                       : i18n("<i>[This message was deleted: %1]</i>", evt.redactedBecause()->reason());
         }
-
         return eventHandler.getRichBody();
     }
 

src/models/messagefiltermodel.cpp

@@ -8,14 +8,15 @@
 #include "enums/delegatetype.h"
 #include "messageeventmodel.h"
 #include "neochatconfig.h"
+#include "timelinemodel.h"
 
 using namespace Quotient;
 
-MessageFilterModel::MessageFilterModel(QObject *parent, MessageEventModel *sourceMessageModel)
+MessageFilterModel::MessageFilterModel(QObject *parent, TimelineModel *sourceModel)
     : QSortFilterProxyModel(parent)
 {
-    Q_ASSERT(sourceMessageModel);
-    setSourceModel(sourceMessageModel);
+    Q_ASSERT(sourceModel);
+    setSourceModel(sourceModel);
 
     connect(NeoChatConfig::self(), &NeoChatConfig::ShowStateEventChanged, this, [this] {
         invalidateFilter();

src/models/messagefiltermodel.h

@@ -7,6 +7,7 @@
 #include <QSortFilterProxyModel>
 
 #include "messageeventmodel.h"
+#include "timelinemodel.h"
 
 /**
  * @class MessageFilterModel
@@ -36,7 +37,7 @@ public:
         LastRole, // Keep this last
     };
 
-    explicit MessageFilterModel(QObject *parent = nullptr, MessageEventModel *sourceMessageModel = nullptr);
+    explicit MessageFilterModel(QObject *parent = nullptr, TimelineModel *sourceModel = nullptr);
 
     /**
      * @brief Custom filter function to remove hidden messages.

src/models/timelinemodel.cpp

@@ -0,0 +1,95 @@
+// SPDX-FileCopyrightText: 2022 James Graham <james.h.graham@protonmail.com>
+// SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
+
+#include "timelinemodel.h"
+
+#include "delegatetype.h"
+
+TimelineModel::TimelineModel(QObject *parent)
+    : QConcatenateTablesProxyModel(parent)
+{
+    m_messageEventModel = new MessageEventModel(this);
+    addSourceModel(m_messageEventModel);
+    m_timelineEndModel = new TimelineEndModel(this);
+    addSourceModel(m_timelineEndModel);
+}
+
+NeoChatRoom *TimelineModel::room() const
+{
+    return m_messageEventModel->room();
+}
+
+void TimelineModel::setRoom(NeoChatRoom *room)
+{
+    // Both models do their own null checking so just pass along.
+    m_messageEventModel->setRoom(room);
+    m_timelineEndModel->setRoom(room);
+}
+
+MessageEventModel *TimelineModel::messageEventModel() const
+{
+    return m_messageEventModel;
+}
+
+QHash<int, QByteArray> TimelineModel::roleNames() const
+{
+    return m_messageEventModel->roleNames();
+}
+
+TimelineEndModel::TimelineEndModel(QObject *parent)
+    : QAbstractListModel(parent)
+{
+}
+
+void TimelineEndModel::setRoom(NeoChatRoom *room)
+{
+    if (room == m_room) {
+        return;
+    }
+
+    beginResetModel();
+
+    if (m_room != nullptr) {
+        m_room->disconnect(this);
+    }
+
+    m_room = room;
+
+    if (m_room != nullptr) {
+        connect(m_room, &Quotient::Room::eventsHistoryJobChanged, this, [this]() {
+            if (m_room->allHistoryLoaded()) {
+                // HACK: We have to do it this way because DelegateChooser doesn't update dynamically.
+                beginRemoveRows({}, 0, 0);
+                endRemoveRows();
+                beginInsertRows({}, 0, 0);
+                endInsertRows();
+            }
+        });
+    }
+
+    endResetModel();
+}
+
+QVariant TimelineEndModel::data(const QModelIndex &idx, int role) const
+{
+    Q_UNUSED(idx)
+    if (m_room == nullptr) {
+        return {};
+    }
+
+    if (role == DelegateTypeRole) {
+        return m_room->allHistoryLoaded() ? DelegateType::TimelineEnd : DelegateType::Loading;
+    }
+    return {};
+}
+
+int TimelineEndModel::rowCount(const QModelIndex &parent) const
+{
+    Q_UNUSED(parent)
+    return 1;
+}
+
+QHash<int, QByteArray> TimelineEndModel::roleNames() const
+{
+    return {{DelegateTypeRole, "delegateType"}};
+}

src/models/timelinemodel.h

@@ -0,0 +1,112 @@
+// SPDX-FileCopyrightText: 2022 James Graham <james.h.graham@protonmail.com>
+// SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
+
+#pragma once
+
+#include <QAbstractListModel>
+#include <QConcatenateTablesProxyModel>
+#include <QQmlEngine>
+
+#include "messageeventmodel.h"
+#include "neochatroom.h"
+
+/**
+ * @class TimelineEndModel
+ *
+ * A model to provide a single delegate to mark the end of the timeline.
+ *
+ * The delegate will either be a loading delegate if more events are being loaded
+ * or a timeline end delegate if all history is loaded.
+ */
+class TimelineEndModel : public QAbstractListModel
+{
+    Q_OBJECT
+    QML_ELEMENT
+
+public:
+    /**
+     * @brief Defines the model roles.
+     */
+    enum Roles {
+        DelegateTypeRole = MessageEventModel::DelegateTypeRole, /**< The delegate type of the message. */
+    };
+    Q_ENUM(Roles)
+
+    explicit TimelineEndModel(QObject *parent = nullptr);
+
+    /**
+     * @brief Set the room for the timeline.
+     */
+    void setRoom(NeoChatRoom *room);
+
+    /**
+     * @brief Get the given role value at the given index.
+     *
+     * @sa QAbstractItemModel::data
+     */
+    [[nodiscard]] QVariant data(const QModelIndex &idx, int role = Qt::DisplayRole) const override;
+
+    /**
+     * @brief 1, the answer is always 1.
+     *
+     * @sa  QAbstractItemModel::rowCount
+     */
+    [[nodiscard]] int rowCount(const QModelIndex &parent = QModelIndex()) const override;
+
+    /**
+     * @brief Returns a map with DelegateTypeRole it's the only one.
+     *
+     * @sa Roles, QAbstractItemModel::roleNames()
+     */
+    [[nodiscard]] QHash<int, QByteArray> roleNames() const override;
+
+private:
+    NeoChatRoom *m_room = nullptr;
+};
+
+/**
+ * @class TimelineModel
+ *
+ * A model to visualise a room timeline.
+ *
+ * This model combines a MessageEventModel with a TimelineEndModel.
+ *
+ * @sa MessageEventModel, TimelineEndModel
+ */
+class TimelineModel : public QConcatenateTablesProxyModel
+{
+    Q_OBJECT
+    QML_ELEMENT
+
+    /**
+     * @brief The current room that the model is getting its messages from.
+     */
+    Q_PROPERTY(NeoChatRoom *room READ room WRITE setRoom NOTIFY roomChanged)
+
+    /**
+     * @brief The MessageEventModel for the timeline.
+     */
+    Q_PROPERTY(MessageEventModel *messageEventModel READ messageEventModel CONSTANT)
+
+public:
+    TimelineModel(QObject *parent = nullptr);
+
+    [[nodiscard]] NeoChatRoom *room() const;
+    void setRoom(NeoChatRoom *room);
+
+    MessageEventModel *messageEventModel() const;
+
+    /**
+     * @brief Returns a mapping from Role enum values to role names.
+     *
+     * @sa Roles, QAbstractProxyModel::roleNames()
+     */
+    [[nodiscard]] QHash<int, QByteArray> roleNames() const override;
+
+Q_SIGNALS:
+    void roomChanged();
+
+private:
+    MessageEventModel *m_messageEventModel = nullptr;
+    TimelineEndModel *m_timelineEndModel = nullptr;
+};