TubeLab-App-Android/app/src/main/java/app/fedilab/fedilabtube/fragment/DisplayNotificationsFragment.java

package app.fedilab.fedilabtube.fragment;
/* Copyright 2020 Thomas Schneider
 *
 * This file is a part of TubeLab
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the
 * GNU General Public License as published by the Free Software Foundation; either version 3 of the
 * License, or (at your option) any later version.
 *
 * TubeLab is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
 * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
 * Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with TubeLab; if not,
 * see <http://www.gnu.org/licenses>. */

import android.content.Context;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.RelativeLayout;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.DividerItemDecoration;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;

import java.util.ArrayList;
import java.util.List;

import app.fedilab.fedilabtube.R;
import app.fedilab.fedilabtube.asynctasks.RetrievePeertubeNotificationsAsyncTask;
import app.fedilab.fedilabtube.client.APIResponse;
import app.fedilab.fedilabtube.client.entities.Account;
import app.fedilab.fedilabtube.client.entities.PeertubeNotification;
import app.fedilab.fedilabtube.drawer.PeertubeNotificationsListAdapter;
import app.fedilab.fedilabtube.interfaces.OnRetrievePeertubeNotificationsInterface;
import es.dmoral.toasty.Toasty;


public class DisplayNotificationsFragment extends Fragment implements OnRetrievePeertubeNotificationsInterface {

    private boolean flag_loading;
    private Context context;
    private AsyncTask<Void, Void, APIResponse> asyncTask;
    private PeertubeNotificationsListAdapter peertubeNotificationsListAdapter;
    private String max_id;
    private List<PeertubeNotification> notifications;
    private RelativeLayout mainLoader, nextElementLoader, textviewNoAction;
    private boolean firstLoad;
    private SwipeRefreshLayout swipeRefreshLayout;
    private boolean swiped;
    private RecyclerView lv_notifications;
    private View rootView;

    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        rootView = inflater.inflate(R.layout.fragment_recyclerview, container, false);

        context = getContext();
        notifications = new ArrayList<>();
        max_id = null;
        firstLoad = true;
        flag_loading = true;
        swiped = false;

        swipeRefreshLayout = rootView.findViewById(R.id.swipeContainer);


        lv_notifications = rootView.findViewById(R.id.lv_elements);
        lv_notifications.addItemDecoration(new DividerItemDecoration(context, DividerItemDecoration.VERTICAL));
        mainLoader = rootView.findViewById(R.id.loader);
        nextElementLoader = rootView.findViewById(R.id.loading_next);
        textviewNoAction = rootView.findViewById(R.id.no_action);
        mainLoader.setVisibility(View.VISIBLE);
        nextElementLoader.setVisibility(View.GONE);
        peertubeNotificationsListAdapter = new PeertubeNotificationsListAdapter(this.notifications);
        lv_notifications.setAdapter(peertubeNotificationsListAdapter);

        final LinearLayoutManager mLayoutManager;
        mLayoutManager = new LinearLayoutManager(context);
        lv_notifications.setLayoutManager(mLayoutManager);
        lv_notifications.addOnScrollListener(new RecyclerView.OnScrollListener() {
            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                if (dy > 0) {
                    int visibleItemCount = mLayoutManager.getChildCount();
                    int totalItemCount = mLayoutManager.getItemCount();
                    int firstVisibleItem = mLayoutManager.findFirstVisibleItemPosition();
                    if (firstVisibleItem + visibleItemCount == totalItemCount) {
                        if (!flag_loading) {
                            flag_loading = true;
                            asyncTask = new RetrievePeertubeNotificationsAsyncTask(context, null, max_id, DisplayNotificationsFragment.this).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
                            nextElementLoader.setVisibility(View.VISIBLE);
                        }
                    } else {
                        nextElementLoader.setVisibility(View.GONE);
                    }
                }
            }
        });
        swipeRefreshLayout.setOnRefreshListener(this::pullToRefresh);

        asyncTask = new RetrievePeertubeNotificationsAsyncTask(context, null, null, DisplayNotificationsFragment.this).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
        return rootView;
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        rootView = null;
    }

    @Override
    public void onCreate(Bundle saveInstance) {
        super.onCreate(saveInstance);
    }


    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        this.context = context;
    }

    public void onDestroy() {
        super.onDestroy();
        if (asyncTask != null && asyncTask.getStatus() == AsyncTask.Status.RUNNING)
            asyncTask.cancel(true);
    }

    public void scrollToTop() {
        if (lv_notifications != null)
            lv_notifications.setAdapter(peertubeNotificationsListAdapter);
    }


    public void pullToRefresh() {
        max_id = null;
        notifications = new ArrayList<>();
        firstLoad = true;
        flag_loading = true;
        swiped = true;
        swipeRefreshLayout.setRefreshing(true);
        asyncTask = new RetrievePeertubeNotificationsAsyncTask(context, null, null, DisplayNotificationsFragment.this).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
    }

    @Override
    public void onRetrievePeertubeNotifications(APIResponse apiResponse, Account account) {
        mainLoader.setVisibility(View.GONE);
        nextElementLoader.setVisibility(View.GONE);
        if (apiResponse.getError() != null) {
            Toasty.error(context, apiResponse.getError().getError(), Toast.LENGTH_LONG).show();
            flag_loading = false;
            swipeRefreshLayout.setRefreshing(false);
            swiped = false;
            return;
        }

        int previousPosition = notifications.size();
        max_id = apiResponse.getMax_id();
        List<PeertubeNotification> notifications = apiResponse.getPeertubeNotifications();
        if (!swiped && firstLoad && (notifications == null || notifications.size() == 0))
            textviewNoAction.setVisibility(View.VISIBLE);
        else
            textviewNoAction.setVisibility(View.GONE);
        if (swiped) {
            if (previousPosition > 0) {
                this.notifications.subList(0, previousPosition).clear();
                peertubeNotificationsListAdapter.notifyItemRangeRemoved(0, previousPosition);
            }
            swiped = false;
        }

        if (notifications != null && notifications.size() > 0) {
            this.notifications.addAll(notifications);
            peertubeNotificationsListAdapter.notifyItemRangeInserted(previousPosition, notifications.size());
        } else {
            if (firstLoad)
                textviewNoAction.setVisibility(View.VISIBLE);
        }
        swipeRefreshLayout.setRefreshing(false);
        firstLoad = false;
        //The initial call comes from a classic tab refresh
        flag_loading = (max_id == null);
    }
}