From 53c75a8dbfffec694db426ba7cc7552226cfaa91 Mon Sep 17 00:00:00 2001
From: td <j.nirve@famedly.com>
Date: Sat, 22 Jun 2024 07:34:16 +0530
Subject: [PATCH] chore: allow clients to set their own voip key delays

---
 lib/src/voip/backend/livekit_backend.dart | 17 ++++++++++++++---
 lib/src/voip/utils/voip_constants.dart    |  2 +-
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/lib/src/voip/backend/livekit_backend.dart b/lib/src/voip/backend/livekit_backend.dart
index 8f0ff189..1a958416 100644
--- a/lib/src/voip/backend/livekit_backend.dart
+++ b/lib/src/voip/backend/livekit_backend.dart
@@ -10,6 +10,16 @@ class LiveKitBackend extends CallBackend {
   final String livekitServiceUrl;
   final String livekitAlias;
 
+  /// A delay after a member leaves before we create and publish a new key, because people
+  /// tend to leave calls at the same time
+  final Duration makeKeyDelay;
+
+  /// The delay between creating and sending a new key and starting to encrypt with it. This gives others
+  /// a chance to receive the new key to minimise the chance they don't get media they can't decrypt.
+  /// The total time between a member leaving and the call switching to new keys is therefore
+  /// makeKeyDelay + useKeyDelay
+  final Duration useKeyDelay;
+
   @override
   final bool e2eeEnabled;
 
@@ -18,6 +28,8 @@ class LiveKitBackend extends CallBackend {
     required this.livekitAlias,
     super.type = 'livekit',
     this.e2eeEnabled = true,
+    this.makeKeyDelay = CallTimeouts.makeKeyDelay,
+    this.useKeyDelay = CallTimeouts.useKeyDelay,
   });
 
   Timer? _memberLeaveEncKeyRotateDebounceTimer;
@@ -165,7 +177,7 @@ class LiveKitBackend extends CallBackend {
     if (delayBeforeUsingKeyOurself) {
       // now wait for the key to propogate and then set it, hopefully users can
       // stil decrypt everything
-      final useKeyTimeout = Future.delayed(CallTimeouts.useKeyDelay, () async {
+      final useKeyTimeout = Future.delayed(useKeyDelay, () async {
         Logs().i(
             '[VOIP E2EE] setting key changed event for ${participant.id} idx $encryptionKeyIndex key $encryptionKeyBin');
         await groupCall.voip.delegate.keyProvider?.onSetEncryptionKey(
@@ -421,8 +433,7 @@ class LiveKitBackend extends CallBackend {
     if (_memberLeaveEncKeyRotateDebounceTimer != null) {
       _memberLeaveEncKeyRotateDebounceTimer!.cancel();
     }
-    _memberLeaveEncKeyRotateDebounceTimer =
-        Timer(CallTimeouts.makeKeyDelay, () async {
+    _memberLeaveEncKeyRotateDebounceTimer = Timer(makeKeyDelay, () async {
       await _makeNewSenderKey(groupCall, true);
     });
   }
diff --git a/lib/src/voip/utils/voip_constants.dart b/lib/src/voip/utils/voip_constants.dart
index f003c0e6..5d20e6b3 100644
--- a/lib/src/voip/utils/voip_constants.dart
+++ b/lib/src/voip/utils/voip_constants.dart
@@ -35,7 +35,7 @@ class CallTimeouts {
   /// a chance to receive the new key to minimise the chance they don't get media they can't decrypt.
   /// The total time between a member leaving and the call switching to new keys is therefore
   /// makeKeyDelay + useKeyDelay
-  static const useKeyDelay = Duration(seconds: 6);
+  static const useKeyDelay = Duration(seconds: 4);
 }
 
 class CallConstants {