feat: render /clear events (#543)

lib/components/chat_history/chat_cleared_event.dart

@@ -0,0 +1,28 @@
+import 'package:flutter/material.dart';
+import 'package:intl/intl.dart';
+import 'package:rtchat/models/messages/message.dart';
+
+class ChatClearedEventWidget extends StatelessWidget {
+  final ChatClearedEventModel model;
+
+  const ChatClearedEventWidget(this.model, {Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    final date = DateFormat.yMMMMEEEEd().format(model.timestamp);
+    final time = DateFormat.jms().format(model.timestamp);
+    return Padding(
+        padding: const EdgeInsets.symmetric(vertical: 8),
+        child: Container(
+          color: Theme.of(context).dividerColor,
+          width: double.infinity,
+          child: Padding(
+              padding: const EdgeInsets.all(8),
+              child: Text(
+                "Chat cleared at $date, $time",
+                textAlign: TextAlign.center,
+                style: Theme.of(context).textTheme.caption,
+              )),
+        ));
+  }
+}

lib/components/chat_history/message.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:provider/provider.dart';
+import 'package:rtchat/components/chat_history/chat_cleared_event.dart';
 import 'package:rtchat/components/chat_history/stream_state_event.dart';
 import 'package:rtchat/components/chat_history/timeout_dialog.dart';
 import 'package:rtchat/components/chat_history/twitch/channel_point_event.dart';
@@ -257,8 +258,10 @@ class ChatHistoryMessage extends StatelessWidget {
         builder: (_, config, __) =>
             config.showEvent ? TwitchRaidingEventWidget(m) : Container(),
       );
+    } else if (m is ChatClearedEventModel) {
+      return ChatClearedEventWidget(m);
     } else {
-      throw AssertionError("invalid message type");
+      throw AssertionError("invalid message type $m");
     }
   }
 }

lib/models/adapters/messages.dart

@@ -35,6 +35,10 @@ class UpdateDeltaEvent extends DeltaEvent {
   const UpdateDeltaEvent(this.messageId, this.update);
 }
 
+class ClearDeltaEvent extends DeltaEvent {
+  const ClearDeltaEvent();
+}
+
 DeltaEvent? _toDeltaEvent(
     List<Emote> emotes, DocumentChange<Map<String, dynamic>> change) {
   final data = change.doc.data();
@@ -102,6 +106,8 @@ DeltaEvent? _toDeltaEvent(
           viewers: data['event']['viewers'],
           timestamp: data['timestamp'].toDate());
       return AppendDeltaEvent(model);
+    case "clear":
+      return const ClearDeltaEvent();
     case "host":
       if (data['hosterChannelId'] == null) {
         // Since we might have some events saved without this field.

lib/models/messages.dart

@@ -44,6 +44,9 @@ class MessagesModel extends ChangeNotifier {
               }
             }
           }
+        } else if (event is ClearDeltaEvent) {
+          _messages = [ChatClearedEventModel()];
+          _tts?.stop();
         }
         notifyListeners();
       });

lib/models/messages/message.dart

@@ -21,3 +21,7 @@ class SystemMessageModel extends MessageModel {
   SystemMessageModel({required this.text})
       : super(messageId: "", timestamp: DateTime.now());
 }
+
+class ChatClearedEventModel extends MessageModel {
+  ChatClearedEventModel() : super(messageId: "", timestamp: DateTime.now());
+}

lib/models/tts.dart

@@ -185,6 +185,10 @@ class TtsModel extends ChangeNotifier {
     _pending.remove(messageId);
   }
 
+  void stop() {
+    _pending.clear();
+  }
+
   TtsModel.fromJson(Map<String, dynamic> json) {
     if (json['isBotMuted'] != null) {
       _isBotMuted = json['isBotMuted'];