grouphandler.kt

class GroupHandler(){    

   private val messagesList = mutableListOf<GroupMessage>()

   private val groupIds = ArrayList<String>()

fun initListener(){
  val db = FirebaseFirestore.getInstance()
  val groupMsgCollection= db.collectionGroup("group_messages")
  groupMsgCollection.whereArrayContains("to", userId!!)
             .addSnapshotListener { snapshots, error ->
                 if (error != null || snapshots == null || snapshots.metadata.isFromCache) {
                      LogMessage.v("Error ${error?.localizedMessage}")
                      return@addSnapshotListener
                    }
                    onSnapShotChanged(snapshots)
             }
  }
  
fun onSnapShotChanged(snapshots: QuerySnapshot){
    messageList.clear()
    groupIds.clear()

   for(snapShot in snapshots){
      val message = snapShot.document.data.toDataClass<GroupMessage>()
      messagesList.add(message)
     if(!groupsIds.contains())
        groupIds.add(message.groupId)
  }
   groupMessageDao.insertMessages(messageList)
   updateUnReadCount()
 }

fun updateUnReadCount(){
    val groupsWithMsgs = dbRepository.getGroupWithMessagesList()
    for (groupWithMsg in groupsWithMsgs) {
       val unreadCount = groupWithMsg.messages.filter {
       val myMessageStatus = myMsgStatus(userId.toString(), it)
         it.from != userId && myMessageStatus < 3
      }.size
    groupWithMsg.group.unRead = unreadCount
  }

      val groups = groupsWithMsgs.map {
                it.group
            }
      dbRepository.insertMultipleGroup(groups)
      updateMessageStatus()
  }

fun updateMessageStatus(){
   val messageUpdater= MessageStatusUpdater()
   messageUpdater.updateToDeliveryOrSeen(myUserId,messageList,true,groupIds)
}

fun myMsgStatus(myUserId: String, msg: GroupMessage): Int{
    val indexOfMyStatus=msg.to.indexOf(myUserId)
    return msg.status[indexOfMyStatus]
 }
}