Actually position the view at the end

It turns out that for whatever reason ListView.posiitionViewAtEnd() ignores any whitespace. This means that when we use the function it goes to the last delegate. This is no good as we have some padding at the bottom to make space for the typing indicator.

So the fix for this is stupid and involves adding a "spacer" delegate to the timeline beginning model which is completely invisible but qml see as a delegate so we can both leave the space and properly position the view at the end.

BUG: 501075

src/timeline/CMakeLists.txt

@@ -13,6 +13,7 @@ ecm_add_qml_module(Timeline GENERATE_PLUGIN_SOURCE
         LoadingDelegate.qml
         PredecessorDelegate.qml
         ReadMarkerDelegate.qml
+        SpacerDelegate.qml
         StateDelegate.qml
         SuccessorDelegate.qml
         TimelineEndDelegate.qml

src/timeline/EventDelegate.qml

@@ -62,6 +62,11 @@ DelegateChooser {
         }
     }
 
+    DelegateChoice {
+        roleValue: DelegateType.Spacer
+        delegate: SpacerDelegate {}
+    }
+
     DelegateChoice {
         roleValue: DelegateType.Other
         delegate: NeoChatConfig.showAllEvents ? hiddenDelegate : emptyDelegate

src/timeline/SpacerDelegate.qml

@@ -0,0 +1,11 @@
+// SPDX-FileCopyrightText: 2025 James Graham <james.h.graham@protonmail.com>
+// SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
+
+import QtQuick
+
+import org.kde.kirigami as Kirigami
+
+Item {
+    width: parent?.width
+    height: Kirigami.Units.largeSpacing + Math.round(Kirigami.Theme.defaultFont.pointSize * 2)
+}

src/timeline/TimelineView.qml

@@ -68,7 +68,6 @@ QQC2.ScrollView {
         verticalLayoutDirection: ListView.BottomToTop
         clip: true
         interactive: Kirigami.Settings.isMobile
-        bottomMargin: Kirigami.Units.largeSpacing + Math.round(Kirigami.Theme.defaultFont.pointSize * 2)
 
         model: root.messageFilterModel
 

src/timeline/enums/delegatetype.h

@@ -42,6 +42,7 @@ public:
         TimelineEnd, /**< A delegate to inform that all messages are loaded. */
         Predecessor, /**< A delegate to show a room predecessor. */
         Successor, /**< A delegate to show a room successor. */
+        Spacer, /**< A spacer because ListView.positionViewAtBeginning() is stupid and ignores white space. */
         Other, /**< Anything that cannot be classified as another type. */
     };
     Q_ENUM(Type);

src/timeline/models/timelinemodel.cpp

@@ -81,12 +81,14 @@ void TimelineBeginningModel::setRoom(NeoChatRoom *room)
 
 QVariant TimelineBeginningModel::data(const QModelIndex &idx, int role) const
 {
-    Q_UNUSED(idx)
     if (m_room == nullptr) {
         return {};
     }
 
     if (role == DelegateTypeRole) {
+        if (idx.row() == 0) {
+            return DelegateType::Spacer;
+        }
         return DelegateType::Successor;
     }
     return {};
@@ -98,7 +100,7 @@ int TimelineBeginningModel::rowCount(const QModelIndex &parent) const
     if (m_room == nullptr) {
         return 1;
     }
-    return m_room->successorId().isEmpty() ? 0 : 1;
+    return m_room->successorId().isEmpty() ? 1 : 2;
 }
 
 QHash<int, QByteArray> TimelineBeginningModel::roleNames() const