From ecb559f687f38f99e60226370b823be9103baa33 Mon Sep 17 00:00:00 2001
From: Salvatore Giordano <salvatoregiordanoo@gmail.com>
Date: Mon, 1 Mar 2021 11:52:32 +0100
Subject: [PATCH] reduce calls to offlinestorage while uploading attachments
 using debounce

---
 packages/stream_chat/lib/src/api/channel.dart |  7 +++++-
 packages/stream_chat/lib/src/debounce.dart    | 23 +++++++++++++++++++
 packages/stream_chat_flutter/pubspec.yaml     |  4 ++++
 .../stream_chat_flutter_core/pubspec.yaml     |  4 ++++
 4 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 packages/stream_chat/lib/src/debounce.dart

diff --git a/packages/stream_chat/lib/src/api/channel.dart b/packages/stream_chat/lib/src/api/channel.dart
index 38f990b0..c45ec409 100644
--- a/packages/stream_chat/lib/src/api/channel.dart
+++ b/packages/stream_chat/lib/src/api/channel.dart
@@ -7,6 +7,7 @@ import 'package:dio/dio.dart';
 import 'package:logging/logging.dart';
 import 'package:rxdart/rxdart.dart';
 import 'package:stream_chat/src/api/retry_queue.dart';
+import 'package:stream_chat/src/debounce.dart';
 import 'package:stream_chat/src/event_type.dart';
 import 'package:stream_chat/src/models/attachment_file.dart';
 import 'package:stream_chat/src/models/channel_state.dart';
@@ -1685,7 +1686,11 @@ class ChannelClientState {
 
   set _channelState(ChannelState v) {
     _channelStateController.add(v);
-    _channel._client.chatPersistenceClient?.updateChannelState(v);
+    debounce(
+      timeout: Duration(milliseconds: 500),
+      target: _channel._client.chatPersistenceClient?.updateChannelState,
+      arguments: [v],
+    );
   }
 
   /// The channel threads related to this channel
diff --git a/packages/stream_chat/lib/src/debounce.dart b/packages/stream_chat/lib/src/debounce.dart
new file mode 100644
index 00000000..c0375cf5
--- /dev/null
+++ b/packages/stream_chat/lib/src/debounce.dart
@@ -0,0 +1,23 @@
+import 'dart:async';
+
+import 'package:meta/meta.dart';
+
+/// Map of timeouts being debounced
+Map timeouts = {};
+
+/// Runs a function avoiding calling it too many times in a [timeoutMS] window
+void debounce({
+  @required Duration timeout,
+  @required Function target,
+  @required List arguments,
+}) {
+  if (timeouts.containsKey(target)) {
+    timeouts[target].cancel();
+  }
+
+  final timer = Timer(timeout, () {
+    Function.apply(target, arguments);
+  });
+
+  timeouts[target] = timer;
+}
diff --git a/packages/stream_chat_flutter/pubspec.yaml b/packages/stream_chat_flutter/pubspec.yaml
index 36b561da..8ad0cd12 100644
--- a/packages/stream_chat_flutter/pubspec.yaml
+++ b/packages/stream_chat_flutter/pubspec.yaml
@@ -48,6 +48,10 @@ dependencies:
   path_provider: ^1.6.27
   video_thumbnail: ^0.2.5+1
 
+dependencies_override:
+  stream_chat_flutter_core:
+    path: ../stream_chat_flutter_core
+
 flutter:
   assets:
     - images/
diff --git a/packages/stream_chat_flutter_core/pubspec.yaml b/packages/stream_chat_flutter_core/pubspec.yaml
index 2896ece3..f9c9a650 100644
--- a/packages/stream_chat_flutter_core/pubspec.yaml
+++ b/packages/stream_chat_flutter_core/pubspec.yaml
@@ -15,6 +15,10 @@ dependencies:
     sdk: flutter
   rxdart: ^0.25.0
 
+dependencies_override:
+  stream_chat:
+    path: ../stream_chat
+
 dev_dependencies:
   mockito: ^4.1.4
   flutter_test: