api: Add updateMessage route

And move the PropagateMode definition from events.dart to
model.dart, since it's no longer specific to an event.

Author: chrisbobbe

lib/api/model/events.dart

@@ -766,14 +766,6 @@ class UpdateMessageEvent extends Event {
   Map<String, dynamic> toJson() => _$UpdateMessageEventToJson(this);
 }
 
-/// As in [UpdateMessageEvent.propagateMode].
-@JsonEnum(fieldRename: FieldRename.snake)
-enum PropagateMode {
-  changeOne,
-  changeLater,
-  changeAll;
-}
-
 /// A Zulip event of type `delete_message`: https://zulip.com/api/get-events#delete_message
 @JsonSerializable(fieldRename: FieldRename.snake)
 class DeleteMessageEvent extends Event {

lib/api/model/events.g.dart

@@ -939,3 +939,13 @@ enum MessageEditState {
     return MessageEditState.none;
   }
 }
+
+/// As in [updateMessage] or [UpdateMessageEvent.propagateMode].
+@JsonEnum(fieldRename: FieldRename.snake, alwaysCreate: true)
+enum PropagateMode {
+  changeOne,
+  changeLater,
+  changeAll;
+
+  String toJson() => _$PropagateModeEnumMap[this]!;
+}

lib/api/model/model.dart

@@ -258,6 +258,39 @@ class SendMessageResult {
   Map<String, dynamic> toJson() => _$SendMessageResultToJson(this);
 }
 
+/// https://zulip.com/api/update-message
+Future<UpdateMessageResult> updateMessage(
+  ApiConnection connection, {
+  required int messageId,
+  TopicName? topic,
+  PropagateMode? propagateMode,
+  bool? sendNotificationToOldThread,
+  bool? sendNotificationToNewThread,
+  String? content,
+  int? streamId,
+}) {
+  return connection.patch('updateMessage', UpdateMessageResult.fromJson, 'messages/$messageId', {
+    if (topic != null) 'topic': RawParameter(topic.apiName),
+    if (propagateMode != null) 'propagate_mode': RawParameter(propagateMode.toJson()),
+    if (sendNotificationToOldThread != null) 'send_notification_to_old_thread': sendNotificationToOldThread,
+    if (sendNotificationToNewThread != null) 'send_notification_to_new_thread': sendNotificationToNewThread,
+    if (content != null) 'content': RawParameter(content),
+    if (streamId != null) 'stream_id': streamId,
+  });
+}
+
+@JsonSerializable(fieldRename: FieldRename.snake)
+class UpdateMessageResult {
+  // final List<DetachedUpload> detachedUploads; // TODO handle
+
+  UpdateMessageResult();
+
+  factory UpdateMessageResult.fromJson(Map<String, dynamic> json) =>
+    _$UpdateMessageResultFromJson(json);
+
+  Map<String, dynamic> toJson() => _$UpdateMessageResultToJson(this);
+}
+
 /// https://zulip.com/api/upload-file
 Future<UploadFileResult> uploadFile(
   ApiConnection connection, {

lib/api/model/model.g.dart

@@ -420,6 +420,67 @@ void main() {
     });
   });
 
+  group('updateMessage', () {
+    Future<UpdateMessageResult> checkUpdateMessage(
+      FakeApiConnection connection, {
+      required int messageId,
+      TopicName? topic,
+      PropagateMode? propagateMode,
+      bool? sendNotificationToOldThread,
+      bool? sendNotificationToNewThread,
+      String? content,
+      int? streamId,
+      required Map<String, String> expected,
+    }) async {
+      final result = await updateMessage(connection,
+        messageId: messageId,
+        topic: topic,
+        propagateMode: propagateMode,
+        sendNotificationToOldThread: sendNotificationToOldThread,
+        sendNotificationToNewThread: sendNotificationToNewThread,
+        content: content,
+        streamId: streamId,
+      );
+      check(connection.lastRequest).isA<http.Request>()
+        ..method.equals('PATCH')
+        ..url.path.equals('/api/v1/messages/$messageId')
+        ..bodyFields.deepEquals(expected);
+      return result;
+    }
+
+    test('topic/content change', () {
+      // A separate test exercises `streamId`;
+      // the API doesn't allow changing channel and content at the same time.
+      return FakeApiConnection.with_((connection) async {
+        connection.prepare(json: UpdateMessageResult().toJson());
+        await checkUpdateMessage(connection,
+          messageId: eg.streamMessage().id,
+          topic: eg.t('new topic'),
+          propagateMode: PropagateMode.changeAll,
+          sendNotificationToOldThread: true,
+          sendNotificationToNewThread: true,
+          content: 'asdf',
+          expected: {
+            'topic': 'new topic',
+            'propagate_mode': 'change_all',
+            'send_notification_to_old_thread': 'true',
+            'send_notification_to_new_thread': 'true',
+            'content': 'asdf',
+          });
+      });
+    });
+
+    test('channel change', () {
+      return FakeApiConnection.with_((connection) async {
+        connection.prepare(json: UpdateMessageResult().toJson());
+        await checkUpdateMessage(connection,
+          messageId: eg.streamMessage().id,
+          streamId: 1,
+          expected: {'stream_id': '1'});
+      });
+    });
+  });
+
   group('uploadFile', () {
     Future<void> checkUploadFile(FakeApiConnection connection, {
       required List<List<int>> content,