Show old display name for name change events

BUG: 457664

imports/NeoChat/Component/Timeline/StateDelegate.qml

@@ -96,7 +96,7 @@ Control {
             Layout.preferredHeight: icon.height
             wrapMode: Text.WordWrap
             textFormat: Text.RichText
-            text: `<style>a {text-decoration: none;}</style><a href="https://matrix.to/#/${author.id}" style="color: ${author.color}">${currentRoom.htmlSafeMemberName(author.id)}</a> ${aggregateDisplay}`
+            text: `<style>a {text-decoration: none;}</style><a href="https://matrix.to/#/${author.id}" style="color: ${author.color}">${model.authorDisplayName}</a> ${aggregateDisplay}`
             onLinkActivated: userDetailDialog.createObject(ApplicationWindow.overlay, {room: currentRoom, user: author.object, displayName: author.displayName, avatarMediaId: author.avatarMediaId, avatarUrl: author.avatarUrl}).open()
         }
     }

src/messageeventmodel.cpp

@@ -60,6 +60,7 @@ QHash<int, QByteArray> MessageEventModel::roleNames() const
     roles[MediaUrlRole] = "mediaUrl";
     roles[VerifiedRole] = "verified";
     roles[DisplayNameForInitialsRole] = "displayNameForInitials";
+    roles[AuthorDisplayNameRole] = "authorDisplayName";
     return roles;
 }
 
@@ -840,6 +841,19 @@ QVariant MessageEventModel::data(const QModelIndex &idx, int role) const
         return user->displayname(m_currentRoom).remove(QStringLiteral(" (%1)").arg(user->id()));
     }
 
+    if (role == AuthorDisplayNameRole) {
+        if (!evt.unsignedJson()["prev_content"]["displayname"].isNull()) {
+            auto previousDisplayName = evt.unsignedJson()["prev_content"]["displayname"].toString().toHtmlEscaped();
+            if (previousDisplayName.isEmpty()) {
+                previousDisplayName = evt.senderId();
+            }
+            return previousDisplayName;
+        } else {
+            auto author = static_cast<NeoChatUser *>(isPending ? m_currentRoom->localUser() : m_currentRoom->user(evt.senderId()));
+            m_currentRoom->htmlSafeMemberName(author->id());
+        }
+    }
+
     return {};
 }
 

src/messageeventmodel.h

@@ -48,9 +48,10 @@ public:
         EventResolvedTypeRole,
         AuthorIdRole,
         VerifiedRole,
-
         // Sender's displayname, always without the matrix id
         DisplayNameForInitialsRole,
+        // The displayname for the event's sender; for name change events, the old displayname
+        AuthorDisplayNameRole,
         LastRole, // Keep this last
     };
     Q_ENUM(EventRoles)