NotificationToBuilder.kt

  private fun Notification.toBuilder(): NotificationCompat.Builder {
    val builder = NotificationCompat.Builder(app, CHANNEL_ID)
      .setSmallIcon(smallIcon.resId)
      .setAutoCancel(flags and Notification.FLAG_AUTO_CANCEL == Notification.FLAG_AUTO_CANCEL)
      .setCategory(category)
      .setStyle(messagingStyle())
      .setContentIntent(contentIntent)
    actions.forEach { action ->
      val actionBuilder = NotificationCompat.Action.Builder(
        action.icon,
        action.title,
        action.actionIntent
      )
      action.remoteInputs.forEach { input ->
        actionBuilder.addRemoteInput(
          RemoteInput.Builder(input.resultKey).setLabel(input.label).build()
        )
      }
      builder.addAction(actionBuilder.build())
    }
    return builder
  }

  private fun Notification.messagingStyle(): MessagingStyle {
    return MessagingStyle.extractMessagingStyleFromNotification(this)
      .require("No messagingStyle on notification?")
  }