sendToDeviceEncryptedChunked method

Implementation

Future<void> sendToDeviceEncryptedChunked(
  List<DeviceKeys> deviceKeys,
  String eventType,
  Map<String, dynamic> message,
) async {
  if (!encryptionEnabled) return;
  // be sure to copy our device keys list
  deviceKeys = List<DeviceKeys>.from(deviceKeys);
  deviceKeys.removeWhere((DeviceKeys k) =>
      k.blocked || (k.userId == userID && k.deviceId == deviceID));
  if (deviceKeys.isEmpty) return;
  message = message.copy(); // make sure we deep-copy the message
  // make sure all the olm sessions are loaded from database
  Logs().v('Sending to device chunked... (${deviceKeys.length} devices)');
  // sort so that devices we last received messages from get our message first
  deviceKeys.sort((keyA, keyB) => keyB.lastActive.compareTo(keyA.lastActive));
  // and now send out in chunks of 20
  const chunkSize = 20;

  // first we send out all the chunks that we await
  var i = 0;
  // we leave this in a for-loop for now, so that we can easily adjust the break condition
  // based on other things, if we want to hard-`await` more devices in the future
  for (; i < deviceKeys.length && i <= 0; i += chunkSize) {
    Logs().v('Sending chunk $i...');
    final chunk = deviceKeys.sublist(
        i,
        i + chunkSize > deviceKeys.length
            ? deviceKeys.length
            : i + chunkSize);
    // and send
    await sendToDeviceEncrypted(chunk, eventType, message);
  }
  // now send out the background chunks
  if (i < deviceKeys.length) {
    // ignore: unawaited_futures
    () async {
      for (; i < deviceKeys.length; i += chunkSize) {
        // wait 50ms to not freeze the UI
        await Future.delayed(Duration(milliseconds: 50));
        Logs().v('Sending chunk $i...');
        final chunk = deviceKeys.sublist(
            i,
            i + chunkSize > deviceKeys.length
                ? deviceKeys.length
                : i + chunkSize);
        // and send
        await sendToDeviceEncrypted(chunk, eventType, message);
      }
    }();
  }
}