group_message_updater.kt

class GroupMsgStatusUpdater {

   fun updateToDeliveryOrSeen(myUserId: String, messageList: List<GroupMessage>,isSeen: Boolean, vararg groupId: String){
        try {
            val batch= firestore.batch()
            val db = FirebaseFirestore.getInstance()
            val groupCollection= db.collection("Groups")
            for (id in groupId){
                val msgSubCollection=groupCollection.document(id).collection("group_messages")
                val filterList=  messageList
                    .filter {
                        val indexOfMyStatus=it.to.indexOf(myUserId)
                        it.from!=myUserId && it.status[indexOfMyStatus]==0 && it.groupId==id }
                    .map {
                        val myIndex=it.to.indexOf(myUserId)
                        it.status[myIndex]=if(isSeen) 3 else 2
                       if(isSeen)
                        it.seenTime[myIndex]= Date()
                        it.deliveryTime[myIndex]=if(it.deliveryTime.length<myIndex) 
                                                    it.deliveryTime[myIndex] else Date()
                        it
                    }
                    for (msg in filterList){
                        batch.update(msgSubCollection
                            .document(msg.id),msg.asMap())
                    }
            }
            batch.commit().addOnSuccessListener {
                LogMessage.v("Batch update success from group")
            }.addOnFailureListener {
                LogMessage.v("Batch update failure ${it.message} from group")
            }
        } catch (e: Exception) {
            e.printStackTrace()
        }
    }

}