Add support for copying & deleting multiple messages at once

BUG: 496458

src/timeline/DelegateContextMenu.qml

@@ -407,6 +407,13 @@ KirigamiComponents.ConvergentContextMenu {
         onTriggered: pinned ? root.room.unpinEvent(root.eventId) : root.room.pinEvent(root.eventId)
     }
 
+    Kirigami.Action {
+        visible: root.messageComponentType !== MessageComponentType.Other
+        text: root.room.selectedMessageCount > 0 && root.room.isMessageSelected(root.eventId) ? i18nc("@action:inmenu", "Deselect Message") : i18nc("@action:inmenu", "Select Message")
+        icon.name: "edit-select-all-symbolic"
+        onTriggered: root.room.toggleMessageSelection(root.eventId)
+    }
+
     Kirigami.Action {
         separator: true
         visible: viewSourceAction.visible

src/timeline/EventDelegate.qml

@@ -2,6 +2,8 @@
 // SPDX-FileCopyrightText: 2024 James Graham <james.h.graham@protonmail.com>
 // SPDX-License-Identifier: GPL-3.0-only
 
+pragma ComponentBehavior: Bound
+
 import QtQuick
 
 import Qt.labs.qmlmodels
@@ -16,6 +18,11 @@ DelegateChooser {
      */
     required property NeoChatRoom room
 
+    /**
+     * @brief Whether to show selection controls for message delegate.
+     */
+    property bool showSelectionControl: false
+
     role: "delegateType"
 
     DelegateChoice {
@@ -25,7 +32,9 @@ DelegateChooser {
 
     DelegateChoice {
         roleValue: DelegateType.Message
-        delegate: MessageDelegate {}
+        delegate: MessageDelegate {
+            showSelectionControl: root.showSelectionControl
+        }
     }
 
     DelegateChoice {

src/timeline/MessageDelegate.qml

@@ -5,6 +5,7 @@ pragma ComponentBehavior: Bound
 
 import QtQuick
 import QtQuick.Controls as QQC2
+import QtQuick.Layouts
 
 import org.kde.kirigami as Kirigami
 import org.kde.kirigamiaddons.components as KirigamiComponents
@@ -109,6 +110,16 @@ MessageDelegateBase {
      */
     property bool showHighlight: root.isHighlighted || isTemporaryHighlighted
 
+    /**
+     * @brief Whether the message is selected.
+     */
+    property bool selected: root.room.selectedMessageCount > 0 && room.isMessageSelected(eventId)
+
+    /**
+     * @brief Whether to show selection controls for this message.
+     */
+    property bool showSelectionControl: false
+
     Message.room: root.room
     Message.timeline: root.ListView.view
     Message.contentModel: root.contentModel
@@ -120,6 +131,7 @@ MessageDelegateBase {
     enableAvatars: NeoChatConfig?.showAvatarInTimeline ?? false
     compactMode: NeoChatConfig?.compactLayout ?? false
     showLocalMessagesOnRight: NeoChatConfig.showLocalMessagesOnRight
+    showSelection: root.showSelectionControl && room.selectedMessageCount > 0
 
     contentItem: Bubble {
         id: bubble
@@ -230,6 +242,20 @@ MessageDelegateBase {
         author: root.author
     }
 
+    selectionComponent: RowLayout {
+        spacing: Kirigami.Units.smallSpacing
+        implicitHeight: Kirigami.Units.gridUnit + Kirigami.Units.largeSpacing * 2
+
+        QQC2.CheckBox {
+            checked: root.selected
+            onClicked: root.room.toggleMessageSelection(root.eventId)
+        }
+
+        Kirigami.Separator {
+            Layout.fillHeight: true
+        }
+    }
+
     QtObject {
         id: _private
 

src/timeline/TimelineView.qml

@@ -213,6 +213,7 @@ QQC2.ScrollView {
         model: root.messageFilterModel
         delegate: EventDelegate {
             room: _private.room
+            showSelectionControl: true
         }
 
         ColumnLayout {

src/timeline/messagedelegate.cpp

@@ -138,7 +138,10 @@ void MessageDelegateBase::setPercentageValues(bool fillWidth)
 
 void MessageDelegateBase::setContentPadding()
 {
-    m_contentSizeHelper.setLeftPadding(m_sizeHelper.leftX() + (leaveAvatarSpace() ? m_avatarSize + m_spacing : 0));
+    qreal selectionOffset = (m_showSelection && m_selectionItem) ? m_selectionItem->implicitWidth() + (m_spacing * 2) : 0;
+    qreal avatarOffset = (leaveAvatarSpace() ? m_avatarSize + m_spacing : 0);
+
+    m_contentSizeHelper.setLeftPadding(m_sizeHelper.leftX() + selectionOffset + avatarOffset);
     m_contentSizeHelper.setRightPadding(m_sizeHelper.rightPadding());
 }
 
@@ -539,6 +542,77 @@ void MessageDelegateBase::updateQuickAction()
     m_quickActionComponent->create(*quickActionIncubator, qmlContext(m_quickActionComponent));
 }
 
+QQmlComponent *MessageDelegateBase::selectionComponent() const
+{
+    return m_selectionComponent;
+}
+
+void MessageDelegateBase::setSelectionComponent(QQmlComponent *selectionComponent)
+{
+    if (selectionComponent == m_selectionComponent) {
+        return;
+    }
+    m_selectionComponent = selectionComponent;
+    Q_EMIT selectionComponentChanged();
+
+    updateSelection();
+}
+
+bool MessageDelegateBase::showSelection() const
+{
+    return m_showSelection;
+}
+
+void MessageDelegateBase::setShowSelection(bool showSelection)
+{
+    if (showSelection == m_showSelection) {
+        return;
+    }
+    m_showSelection = showSelection;
+    Q_EMIT showSelectionChanged();
+
+    updateSelection();
+}
+
+void MessageDelegateBase::updateSelection()
+{
+    if (m_selectionComponent && showSelection() && !m_selectionItem && !m_selectionIncubating) {
+        const auto selectionIncubator = new MessageObjectIncubator(
+            m_objectInitialCallback,
+            [this](MessageObjectIncubator *incubator) {
+                if (!incubator) {
+                    return;
+                }
+                const auto selectionObject = qobject_cast<QQuickItem *>(incubator->object());
+                if (selectionObject) {
+                    // The setting may have changed during the incubation period.
+                    if (showSelection()) {
+                        m_selectionItem = selectionObject;
+                    } else {
+                        cleanupItem(selectionObject);
+                    }
+                    setContentPadding();
+                    markAsDirty();
+                }
+                m_selectionIncubating = false;
+                // We can't cleanup the incubator in the completedCallback otherwise
+                // we use after free when we return to the status changed function
+                // of that incubator
+                QTimer::singleShot(0, this, [this, incubator]() {
+                    cleanupIncubator(incubator);
+                });
+            },
+            m_errorCallback);
+        m_activeIncubators.push_back(selectionIncubator);
+        m_selectionComponent->create(*selectionIncubator, qmlContext(m_selectionComponent));
+        m_selectionIncubating = true;
+    } else if (!showSelection() && m_selectionItem) {
+        cleanupItem(m_selectionItem);
+        setContentPadding();
+        markAsDirty();
+    }
+}
+
 bool MessageDelegateBase::showLocalMessagesOnRight() const
 {
     return m_showLocalMessagesOnRight;
@@ -623,10 +697,17 @@ void MessageDelegateBase::resizeContent()
         nextY += m_sectionItem->implicitHeight() + m_spacing;
     }
     qreal yAdd = 0.0;
+    if (m_showSelection && m_selectionItem) {
+        m_selectionItem->setPosition(QPointF(m_sizeHelper.leftX(), nextY));
+        m_selectionItem->setSize(QSizeF(m_selectionItem->implicitWidth(), m_selectionItem->implicitHeight()));
+        yAdd = m_selectionItem->implicitHeight();
+    }
     if (showAvatar() && m_avatarItem) {
-        m_avatarItem->setPosition(QPointF(m_sizeHelper.leftX(), nextY));
+        m_avatarItem->setPosition(
+            QPointF(m_showSelection && m_selectionItem ? m_sizeHelper.leftX() + m_selectionItem->implicitWidth() + (m_spacing * 2) : m_sizeHelper.leftX(),
+                    nextY));
         m_avatarItem->setSize(QSizeF(m_avatarItem->implicitWidth(), m_avatarItem->implicitHeight()));
-        yAdd = m_avatarItem->implicitWidth();
+        yAdd = std::max(yAdd, m_avatarItem->implicitHeight());
     }
     if (m_contentItem) {
         const auto contentItemWidth =

src/timeline/messagedelegate.h

@@ -101,6 +101,16 @@ class MessageDelegateBase : public TimelineDelegate
      */
     Q_PROPERTY(QQmlComponent *quickActionComponent READ quickActionComponent WRITE setQuickActionComponent NOTIFY quickActionComponentChanged FINAL)
 
+    /**
+     * @brief The component to use to visualize message selection.
+     */
+    Q_PROPERTY(QQmlComponent *selectionComponent READ selectionComponent WRITE setSelectionComponent NOTIFY selectionComponentChanged FINAL)
+
+    /**
+     * @brief Whether to show the selection component.
+     */
+    Q_PROPERTY(bool showSelection READ showSelection WRITE setShowSelection NOTIFY showSelectionChanged FINAL REQUIRED)
+
     /**
      * @brief Whether to use the compact mode appearance.
      */
@@ -161,6 +171,11 @@ public:
     QQmlComponent *quickActionComponent() const;
     void setQuickActionComponent(QQmlComponent *quickActionComponent);
 
+    QQmlComponent *selectionComponent() const;
+    void setSelectionComponent(QQmlComponent *selectionComponent);
+    bool showSelection() const;
+    void setShowSelection(bool showSelection);
+
     bool showLocalMessagesOnRight() const;
     void setShowLocalMessagesOnRight(bool showLocalMessagesOnRight);
 
@@ -182,6 +197,8 @@ Q_SIGNALS:
     void showReadMarkersChanged();
     void compactBackgroundComponentChanged();
     void quickActionComponentChanged();
+    void selectionComponentChanged();
+    void showSelectionChanged();
     void compactModeChanged();
     void showLocalMessagesOnRightChanged();
     void isTemporaryHighlightedChanged();
@@ -227,6 +244,12 @@ private:
     bool m_quickActionIncubating = false;
     QPointer<QQuickItem> m_quickActionItem;
 
+    QPointer<QQmlComponent> m_selectionComponent;
+    bool m_selectionIncubating = false;
+    QPointer<QQuickItem> m_selectionItem;
+    bool m_showSelection = false;
+    void updateSelection();
+
     bool m_showLocalMessagesOnRight = true;
 
     bool m_hovered = false;