api [nfc]: Rename StreamEvent to ChannelEvent, and subclasses

Fixes parts of zulip#631

Author: Khader-1

lib/api/model/events.dart

@@ -37,8 +37,8 @@ sealed class Event {
         }
       case 'stream':
         switch (json['op'] as String) {
-          case 'create': return StreamCreateEvent.fromJson(json);
-          case 'delete': return StreamDeleteEvent.fromJson(json);
+          case 'create': return ChannelCreateEvent.fromJson(json);
+          case 'delete': return ChannelDeleteEvent.fromJson(json);
           // TODO(#182): case 'update': …
           default: return UnexpectedEvent.fromJson(json);
         }
@@ -332,51 +332,51 @@ class RealmUserUpdateEvent extends RealmUserEvent {
 ///
 /// The corresponding API docs are in several places for
 /// different values of `op`; see subclasses.
-sealed class StreamEvent extends Event {
+sealed class ChannelEvent extends Event {
   @override
   @JsonKey(includeToJson: true)
   String get type => 'stream';
 
   String get op;
 
-  StreamEvent({required super.id});
+  ChannelEvent({required super.id});
 }
 
-/// A [StreamEvent] with op `create`: https://zulip.com/api/get-events#stream-create
+/// A [ChannelEvent] with op `create`: https://zulip.com/api/get-events#stream-create
 @JsonSerializable(fieldRename: FieldRename.snake)
-class StreamCreateEvent extends StreamEvent {
+class ChannelCreateEvent extends ChannelEvent {
   @override
   String get op => 'create';
 
   final List<ZulipStream> streams;
 
-  StreamCreateEvent({required super.id, required this.streams});
+  ChannelCreateEvent({required super.id, required this.streams});
 
-  factory StreamCreateEvent.fromJson(Map<String, dynamic> json) =>
-    _$StreamCreateEventFromJson(json);
+  factory ChannelCreateEvent.fromJson(Map<String, dynamic> json) =>
+    _$ChannelCreateEventFromJson(json);
 
   @override
-  Map<String, dynamic> toJson() => _$StreamCreateEventToJson(this);
+  Map<String, dynamic> toJson() => _$ChannelCreateEventToJson(this);
 }
 
-/// A [StreamEvent] with op `delete`: https://zulip.com/api/get-events#stream-delete
+/// A [ChannelEvent] with op `delete`: https://zulip.com/api/get-events#stream-delete
 @JsonSerializable(fieldRename: FieldRename.snake)
-class StreamDeleteEvent extends StreamEvent {
+class ChannelDeleteEvent extends ChannelEvent {
   @override
   String get op => 'delete';
 
   final List<ZulipStream> streams;
 
-  StreamDeleteEvent({required super.id, required this.streams});
+  ChannelDeleteEvent({required super.id, required this.streams});
 
-  factory StreamDeleteEvent.fromJson(Map<String, dynamic> json) =>
-    _$StreamDeleteEventFromJson(json);
+  factory ChannelDeleteEvent.fromJson(Map<String, dynamic> json) =>
+    _$ChannelDeleteEventFromJson(json);
 
   @override
-  Map<String, dynamic> toJson() => _$StreamDeleteEventToJson(this);
+  Map<String, dynamic> toJson() => _$ChannelDeleteEventToJson(this);
 }
 
-// TODO(#182) StreamUpdateEvent, for a [StreamEvent] with op `update`:
+// TODO(#182) ChannelUpdateEvent, for a [ChannelEvent] with op `update`:
 //   https://zulip.com/api/get-events#stream-update
 
 /// A Zulip event of type `subscription`.

lib/api/model/events.g.dart

@@ -129,9 +129,9 @@ class ChannelStoreImpl with ChannelStore {
     return false;
   }
 
-  void handleStreamEvent(StreamEvent event) {
+  void handleChannelEvent(ChannelEvent event) {
     switch (event) {
-      case StreamCreateEvent():
+      case ChannelCreateEvent():
         assert(event.streams.every((stream) =>
           !streams.containsKey(stream.streamId)
           && !streamsByName.containsKey(stream.name)));
@@ -140,7 +140,7 @@ class ChannelStoreImpl with ChannelStore {
         // (Don't touch `subscriptions`. If the user is subscribed to the stream,
         // details will come in a later `subscription` event.)
 
-      case StreamDeleteEvent():
+      case ChannelDeleteEvent():
         for (final stream in event.streams) {
           assert(identical(streams[stream.streamId], streamsByName[stream.name]));
           assert(subscriptions[stream.streamId] == null

lib/model/channel.dart

@@ -477,9 +477,9 @@ class PerAccountStore extends ChangeNotifier with ChannelStore, MessageStore {
         autocompleteViewManager.handleRealmUserUpdateEvent(event);
         notifyListeners();
 
-      case StreamEvent():
+      case ChannelEvent():
         assert(debugLog("server event: stream/${event.op}"));
-        _channels.handleStreamEvent(event);
+        _channels.handleChannelEvent(event);
         notifyListeners();
 
       case SubscriptionEvent():

lib/model/store.dart

@@ -134,7 +134,7 @@ extension PerAccountStoreTestExtension on PerAccountStore {
   }
 
   Future<void> addStreams(List<ZulipStream> streams) async {
-    await handleEvent(StreamCreateEvent(id: 1, streams: streams));
+    await handleEvent(ChannelCreateEvent(id: 1, streams: streams));
   }
 
   Future<void> addSubscription(Subscription subscription) async {

test/model/test_store.dart

@@ -406,7 +406,7 @@ void main() {
 
       testWidgets('show stream name from stream data when known', (tester) async {
         final streamBefore = eg.stream(name: 'old stream name');
-        // TODO(#182) this test would be more realistic using a StreamUpdateEvent
+        // TODO(#182) this test would be more realistic using a ChannelUpdateEvent
         final streamAfter = ZulipStream.fromJson({
           ...(deepToJson(streamBefore) as Map<String, dynamic>),
           'name': 'new stream name',