api: Add presence event

Author: chrisbobbe

lib/api/model/events.dart

@@ -74,6 +74,7 @@ sealed class Event {
         }
       case 'submessage': return SubmessageEvent.fromJson(json);
       case 'typing': return TypingEvent.fromJson(json);
+      case 'presence': return PresenceEvent.fromJson(json);
       case 'reaction': return ReactionEvent.fromJson(json);
       case 'heartbeat': return HeartbeatEvent.fromJson(json);
       // TODO add many more event types
@@ -1195,6 +1196,69 @@ enum TypingOp {
   String toJson() => _$TypingOpEnumMap[this]!;
 }
 
+/// A Zulip event of type `presence`.
+///
+/// See:
+///   https://zulip.com/api/get-events#presence
+@JsonSerializable(fieldRename: FieldRename.snake)
+class PresenceEvent extends Event {
+  @override
+  @JsonKey(includeToJson: true)
+  String get type => 'presence';
+
+  final int userId;
+  // final String email; // deprecated; ignore
+  final int serverTimestamp;
+  final Map<String, PerClientPresence> presence;
+
+  PresenceEvent({
+    required super.id,
+    required this.userId,
+    required this.serverTimestamp,
+    required this.presence,
+  });
+
+  factory PresenceEvent.fromJson(Map<String, dynamic> json) =>
+    _$PresenceEventFromJson(json);
+
+  @override
+  Map<String, dynamic> toJson() => _$PresenceEventToJson(this);
+}
+
+/// A value in [PresenceEvent.presence].
+///
+/// The "per client" name follows the event's structure,
+/// but that structure is already an API wart; see the doc's "Changes" note
+/// on [client] and on the `client_name` key of the map that holds these values:
+///
+/// https://zulip.com/api/get-events#presence
+/// > Starting with Zulip 7.0 (feature level 178), this will always be "website"
+/// > as the server no longer stores which client submitted presence updates.
+///
+/// This will probably be deprecated in favor of a form like [PerUserPresence].
+/// See #1611 and discussion:
+///   https://chat.zulip.org/#narrow/channel/378-api-design/topic/presence.20rewrite/near/2200812
+// TODO(#1611) update comment about #1611
+@JsonSerializable(fieldRename: FieldRename.snake)
+class PerClientPresence {
+  final String client; // always "website" (on 7.0+, so on all supported servers)
+  final PresenceStatus status;
+  final int timestamp;
+  final bool pushable; // always false (on 7.0+, so on all supported servers)
+
+  PerClientPresence({
+    required this.client,
+    required this.status,
+    required this.timestamp,
+    required this.pushable,
+  });
+
+  factory PerClientPresence.fromJson(Map<String, dynamic> json) =>
+    _$PerClientPresenceFromJson(json);
+
+  Map<String, dynamic> toJson() => _$PerClientPresenceToJson(this);
+}
+
 /// A Zulip event of type `reaction`, with op `add` or `remove`.
 ///
 /// See:

lib/api/model/events.g.dart

@@ -350,6 +350,15 @@ class PerUserPresence {
   Map<String, dynamic> toJson() => _$PerUserPresenceToJson(this);
 }
 
+/// As in [PerClientPresence.status].
+@JsonEnum(fieldRename: FieldRename.snake, alwaysCreate: true)
+enum PresenceStatus {
+  active,
+  idle;
+
+  String toJson() => _$PresenceStatusEnumMap[this]!;
+}
+
 /// An item in `saved_snippets` from the initial snapshot.
 ///
 /// For docs, search for "saved_snippets:"

lib/api/model/model.dart

@@ -952,6 +952,10 @@ class PerAccountStore extends PerAccountStoreBase with ChangeNotifier, EmojiStor
         assert(debugLog("server event: typing/${event.op} ${event.messageType}"));
         typingStatus.handleTypingEvent(event);
 
+      case PresenceEvent():
+        // TODO handle
+        break;
+
       case ReactionEvent():
         assert(debugLog("server event: reaction/${event.op}"));
         _messages.handleReactionEvent(event);