main screen

class Home : Fragment() {
    lateinit var auth: FirebaseAuth
    lateinit var db:FirebaseFirestore
    lateinit var itemsCells: ArrayList<post_data?>
    lateinit var loadMoreItemsCells: ArrayList<post_data>
    lateinit var adapterLinear: Items_LinearRVAdapter
    lateinit var scrollListener: RecyclerViewLoadMoreScroll
    lateinit var mLayoutManager: RecyclerView.LayoutManager
    lateinit var root:View
    lateinit var lastVisable:DocumentSnapshot
    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        // Inflate the layout for this fragment
         root= inflater.inflate(R.layout.fragment_home, container, false)
        db=Firebase.firestore

        //** Set the data for our ArrayList
        setItemsData()

        //** Set the adapterLinear of the RecyclerView
       setAdapter()

        //** Set the Layout Manager of the RecyclerView
        setRVLayoutManager()

        //** Set the scrollListerner of the RecyclerView
        setRVScrollListener()


        return root
    }




    private fun setItemsData() {
        itemsCells = ArrayList()
        loadingData(10,itemsCells)

    }

    private fun setAdapter() {
        adapterLinear = Items_LinearRVAdapter(itemsCells)
        root.rc_posts.adapter = adapterLinear
        adapterLinear.notifyDataSetChanged()



    }

    private fun setRVLayoutManager() {
        mLayoutManager = LinearLayoutManager(activity!!)
        root.rc_posts.layoutManager = mLayoutManager
        root.rc_posts.setHasFixedSize(true)

    }

    private fun setRVScrollListener() {
        mLayoutManager = LinearLayoutManager(activity!!)
        scrollListener = RecyclerViewLoadMoreScroll(mLayoutManager as LinearLayoutManager)
        scrollListener.setOnLoadMoreListener(object :
            OnLoadMoreListener {
            override fun onLoadMore() {
                LoadMoreData()
            }
        })
        root.rc_posts.addOnScrollListener(scrollListener)
    }

    private fun LoadMoreData() {
        //Add the Loading View
        adapterLinear.addLoadingView()
        //Create the loadMoreItemsCells Arraylist
        loadMoreItemsCells=ArrayList()
        //Get the number of the current Items of the main Arraylist
       // val start = adapterLinear.itemCount.toLong()
        Log.e("arr","item_count $start")
        //Load 16 more items
        //val end:Long= start + 5
        //Use Handler if the items are loading too fast.
        //If you remove it, the data will load so fast that you can't even see the LoadingView

            auth=Firebase.auth

            db.collection("Users").limit(10).get().addOnSuccessListener {querySnapshot ->

                for (uid in querySnapshot){
                    val uid2=uid.getString("UserId").toString()

                    db.collection("Users").document(uid2).get().addOnSuccessListener { documentSnapshot ->
                        val username=documentSnapshot.getString("UserName").toString()
                        val profile_img=documentSnapshot.getString("Image_Url").toString()
                        Log.e("arr","p1")


                    db.collection("Users").document(uid2).collection("MyPosts").orderBy("post_time",Query.Direction.DESCENDING).startAfter(lastVisable).limit(10).get().addOnSuccessListener { querySnapshot ->
                        if (!querySnapshot.isEmpty){
                            lastVisable = querySnapshot.documents[querySnapshot.size() - 1]

                        }

                        for (doc in querySnapshot){
                            val time= doc.get("post_time").toString()
                            val description=doc.getString("post_details").toString()
                            val like_count=doc.get("like_count").toString()
                            val commint_count=doc.get("comment_count").toString()


                            val video:String
                            if (doc?.getString("post_video") == null) {
                                video = ""
                            } else {
                                video = doc.getString("post_video").toString()
                            }



                            val img:ArrayList<String>
                            if (doc.get("post_img")!=null){
                                img=doc.get("post_img") as ArrayList<String>
                            }else{
                                img=ArrayList()
                            }

                            val url=ArrayList<SlideModel>()
                            url.add(SlideModel("https://www.w3schools.com/w3css/img_lights.jpg"))
                            url.add(SlideModel("https://www.talkwalker.com/images/2020/blog-headers/image-analysis.png"))
                            Log.e("arr","p2")
                            loadMoreItemsCells.add(post_data(uid2,username,profile_img,time,description,
                                img,video,like_count,commint_count))

                        }
                        adapterLinear.removeLoadingView()
                        //We adding the data to our main ArrayList
                        adapterLinear.addData(loadMoreItemsCells)
                        //Change the boolean isLoading to false
                        scrollListener.setLoaded()
                        //Update the recyclerView in the main thread
                        root.rc_posts.post {
                            adapterLinear.notifyDataSetChanged()
                        }
                    }

                    }.addOnFailureListener {
                        Log.e("error",it.message.toString())
                    }
                }
            }

    }





    private fun loadingData(limit: Long,array: ArrayList<post_data?>){
    auth=Firebase.auth
    val user_array=ArrayList<String>()
    var user_id=""
    db.collection("Users").limit(limit).get().addOnSuccessListener {querySnapshot ->
        try {
            for (user in querySnapshot){
                user_id=user.getString("UserId").toString()
                user_array.add(user_id.toString())
            }
            for (uid in user_array){
                db.collection("Users").document(uid).collection("MyPosts").orderBy("post_time",Query.Direction.DESCENDING).limit(limit).get().addOnSuccessListener {querySnapshot ->
                   lastVisable = querySnapshot.documents[querySnapshot.size() - 1]
                    for (doc in querySnapshot){
                        val time= doc.get("post_time").toString()
                        val description=doc.getString("post_details").toString()
                        val like_count=doc.get("like_count").toString()
                        val commint_count=doc.get("comment_count").toString()


                        val video:String
                        if (doc?.getString("post_video") == null) {
                            video = ""
                        } else {
                            video = doc.getString("post_video").toString()
                        }


                        val img:ArrayList<String>
                        if (doc.get("post_img")!=null){
                            img=doc.get("post_img") as ArrayList<String>
                        }else{
                            img=ArrayList()
                        }



                        db.collection("Users").document(uid).get().addOnSuccessListener { documentSnapshot ->
                            val username=documentSnapshot.getString("UserName").toString()
                            val profile_img=documentSnapshot.getString("Image_Url").toString()
                            array.add(post_data(user_id,username,profile_img,time,description,img,video,like_count,commint_count))
                            adapterLinear.notifyDataSetChanged()
                        }
                    }
                }.addOnFailureListener {
                    Log.e("error",it.message.toString())
                }

            }
        }catch (r:RuntimeException){}

    }



}






}