wip msglist: Handle update_message_flags events in model

Author: chrisbobbe

lib/model/message_list.dart

@@ -341,6 +341,38 @@ class MessageListView with ChangeNotifier, _MessageSequence {
     notifyListeners();
   }
 
+  void maybeUpdateMessageFlags(UpdateMessageFlagsEvent event) {
+    final List<Message> messagesToProcess;
+    if (event.all) {
+      messagesToProcess = messages;
+    } else {
+      messagesToProcess = [];
+      for (final messageId in event.messages) {
+        // TODO(perf) could be more efficient?
+        final index = _findMessageWithId(messageId);
+        if (index != -1) {
+          messagesToProcess.add(messages[index]);
+        }
+      }
+    }
+    if (messagesToProcess.isEmpty) {
+      return;
+    }
+
+    switch (event) {
+      case UpdateMessageFlagsAddEvent():
+        for (final message in messagesToProcess) {
+          message.flags.add(event.flag);
+        }
+      case UpdateMessageFlagsRemoveEvent():
+        for (final message in messagesToProcess) {
+          message.flags.remove(event.flag);
+        }
+    }
+
+    notifyListeners();
+  }
+
   void maybeUpdateMessageReactions(ReactionEvent event) {
     final index = _findMessageWithId(event.messageId);
     if (index == -1) {

lib/model/store.dart

@@ -311,7 +311,9 @@ class PerAccountStore extends ChangeNotifier {
       // TODO handle
     } else if (event is UpdateMessageFlagsEvent) {
       assert(debugLog("server event: update_message_flags/${event.op} ${event.flag.toJson()}"));
-      // TODO handle
+      for (final view in _messageListViews) {
+        view.maybeUpdateMessageFlags(event);
+      }
     } else if (event is ReactionEvent) {
       assert(debugLog("server event: reaction/${event.op}"));
       for (final view in _messageListViews) {