msglist: Handle updated events in MessageListView (#118).

Processes an UpdateMessageEvent and hands it off to the MessageListView to update, if the message is visible in the MessageListView. This completes the changes required for issue #118.

lib/api/model/model.dart

@@ -250,13 +250,13 @@ class Subscription {
 sealed class Message {
   final String? avatarUrl;
   final String client;
-  final String content;
+  String content;
   final String contentType;
 
   // final List<MessageEditHistory> editHistory; // TODO handle
   final int id;
-  final bool isMeMessage;
-  final int? lastEditTimestamp;
+  bool isMeMessage;
+  int? lastEditTimestamp;
 
   // final List<Reaction> reactions; // TODO handle
   final int recipientId;
@@ -271,7 +271,7 @@ sealed class Message {
 
   // final List<TopicLink> topicLinks; // TODO handle
   // final string type; // handled by runtime type of object
-  final List<String> flags; // TODO enum
+  List<String> flags; // TODO enum
   final String? matchContent;
   final String? matchSubject;
 

lib/model/message_list.dart

@@ -1,5 +1,7 @@
+import 'package:collection/collection.dart';
 import 'package:flutter/foundation.dart';
 
+import '../api/model/events.dart';
 import '../api/model/model.dart';
 import '../api/route/messages.dart';
 import 'content.dart';
@@ -86,6 +88,67 @@ class MessageListView extends ChangeNotifier {
     notifyListeners();
   }
 
+  applyChangesToMessage(UpdateMessageEvent event, Message message) {
+    if (event.renderingOnly != null && event.renderingOnly == true) {
+      //TODO update inline preview
+      return;
+    }
+
+    if (!event.flags.equals(message.flags)) {
+      //TODO Possibly a new @alert on this message. Update alerts.
+      message.flags = event.flags;
+    }
+
+    if (event.renderedContent != null) {
+      message.content = event.renderedContent as String;
+    }
+
+    if (event.editTimestamp != null) {
+      message.lastEditTimestamp = event.editTimestamp;
+    }
+
+    if (event.isMeMessage != null) {
+      message.isMeMessage = event.isMeMessage as bool;
+    }
+
+  }
+
+  ///This is almost directly copied from package:collection/algorithms.dart.
+  ///The way that package was set up doesn't allow us to search
+  ///for a message ID among a bunch of message objects - this is a quick
+  ///modification of that method to work here for us.
+  int findMessageWithId(int messageId) {
+  var min = 0;
+  var max = messages.length;
+
+  while (min < max) {
+    var mid = min + ((max - min) >> 1);
+    Message message = messages[mid];
+    var comp = message.id.compareTo(messageId);
+    if (comp == 0) return mid;
+    if (comp < 0) {
+      min = mid + 1;
+    } else {
+      max = mid;
+    }
+  }
+  return -1;
+}
+
+  void maybeUpdateMessage(UpdateMessageEvent event) {
+    int idx = findMessageWithId(event.messageId);
+
+    if (idx == -1)  {
+      return;
+    }
+
+    Message message = messages[idx];
+    applyChangesToMessage(event, message);
+
+    contents[idx] = parseContent(message.content);
+    notifyListeners();
+  }
+
   /// Called when the app is reassembled during debugging, e.g. for hot reload.
   ///
   /// This will redo from scratch any computations we can, such as parsing

lib/model/store.dart

@@ -272,7 +272,9 @@ class PerAccountStore extends ChangeNotifier {
       }
     } else if (event is UpdateMessageEvent) {
       assert(debugLog("server event: update_message ${event.messageId}"));
-      // TODO handle
+      for (final view in _messageListViews) {
+        view.maybeUpdateMessage(event);
+      }
     } else if (event is DeleteMessageEvent) {
       assert(debugLog("server event: delete_message ${event.messageIds}"));
       // TODO handle