feat: Add read marker

assets/l10n/intl_en.arb

@@ -2527,5 +2527,6 @@
             "path": {}
         }
     },
-    "jumpToLastReadMessage": "Jump to last read message"
+    "jumpToLastReadMessage": "Jump to last read message",
+    "readUpToHere": "Read up to here"
 }

lib/pages/chat/chat.dart

@@ -53,6 +53,8 @@ class ChatController extends State<Chat> {
 
   MatrixState? matrix;
 
+  String? readMarkerEventId;
+
   String? get roomId => context.vRouter.pathParameters['roomid'];
 
   final AutoScrollController scrollController = AutoScrollController();

lib/pages/chat/chat_event_list.dart

@@ -123,6 +123,8 @@ class ChatEventList extends StatelessWidget {
                     selected: controller.selectedEvents
                         .any((e) => e.eventId == event.eventId),
                     timeline: controller.timeline!,
+                    displayReadMarker:
+                        controller.readMarkerEventId == event.eventId,
                     nextEvent: i < controller.timeline!.events.length
                         ? controller.timeline!.events[i]
                         : null,

lib/pages/chat/chat_view.dart

@@ -143,6 +143,7 @@ class ChatView extends StatelessWidget {
     final client = controller.matrix!.client;
     controller.sendingClient ??= client;
     controller.room = controller.sendingClient!.getRoomById(controller.roomId!);
+    controller.readMarkerEventId ??= controller.room!.fullyRead;
     if (controller.room == null) {
       return Scaffold(
         appBar: AppBar(

lib/pages/chat/events/message.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 
+import 'package:flutter_gen/gen_l10n/l10n.dart';
 import 'package:matrix/matrix.dart';
 import 'package:swipe_to_action/swipe_to_action.dart';
 
@@ -18,6 +19,7 @@ import 'verification_request_content.dart';
 class Message extends StatelessWidget {
   final Event event;
   final Event? nextEvent;
+  final bool displayReadMarker;
   final void Function(Event)? onSelect;
   final void Function(Event)? onAvatarTab;
   final void Function(Event)? onInfoTab;
@@ -30,6 +32,7 @@ class Message extends StatelessWidget {
   const Message(
     this.event, {
     this.nextEvent,
+    this.displayReadMarker = false,
     this.longPressSelect = false,
     this.onSelect,
     this.onInfoTab,
@@ -303,7 +306,8 @@ class Message extends StatelessWidget {
     Widget container;
     if (event.hasAggregatedEvents(timeline, RelationshipTypes.reaction) ||
         displayTime ||
-        selected) {
+        selected ||
+        displayReadMarker) {
       container = Column(
         mainAxisSize: MainAxisSize.min,
         crossAxisAlignment:
@@ -347,6 +351,17 @@ class Message extends StatelessWidget {
               ),
               child: MessageReactions(event, timeline),
             ),
+          if (displayReadMarker)
+            Row(
+              children: [
+                const Expanded(child: Divider()),
+                Padding(
+                  padding: const EdgeInsets.all(8.0),
+                  child: Text(L10n.of(context)!.readUpToHere),
+                ),
+                const Expanded(child: Divider()),
+              ],
+            ),
         ],
       );
     } else {

lib/pages/chat/input_bar.dart

@@ -458,11 +458,12 @@ class InputBar extends StatelessWidget {
               buildSuggestion(c, s, Matrix.of(context).client),
           onSuggestionSelected: (Map<String, String?> suggestion) =>
               insertSuggestion(context, suggestion),
-          errorBuilder: (BuildContext context, Object? error) => const SizedBox.shrink(),
+          errorBuilder: (BuildContext context, Object? error) =>
+              const SizedBox.shrink(),
           loadingBuilder: (BuildContext context) => const SizedBox.shrink(),
           // fix loading briefly flickering a dark box
-          noItemsFoundBuilder: (BuildContext context) =>
+          noItemsFoundBuilder: (BuildContext context) => const SizedBox
-              const SizedBox.shrink(), // fix loading briefly showing no suggestions
+              .shrink(), // fix loading briefly showing no suggestions
         ),
       ),
     );

lib/pages/settings_multiple_emotes/settings_multiple_emotes_view.dart

@@ -35,7 +35,8 @@ class MultipleEmotesSettingsView extends StatelessWidget {
           final keys = packs.keys.toList();
           keys.sort();
           return ListView.separated(
-            separatorBuilder: (BuildContext context, int i) => const SizedBox.shrink(),
+            separatorBuilder: (BuildContext context, int i) =>
+                const SizedBox.shrink(),
             itemCount: keys.length,
             itemBuilder: (BuildContext context, int i) {
               final event = packs[keys[i]];