Audinaut-subsonic-app-android/app/src/main/java/net/nullsum/audinaut/adapter/EntryInfiniteGridAdapter.java

/*
  This file is part of Subsonic.
    Subsonic 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.
    Subsonic 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 Subsonic. If not, see <http://www.gnu.org/licenses/>.
    Copyright 2015 (C) Scott Jackson
*/

package net.nullsum.audinaut.adapter;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import net.nullsum.audinaut.R;
import net.nullsum.audinaut.domain.MusicDirectory;
import net.nullsum.audinaut.domain.MusicDirectory.Entry;
import net.nullsum.audinaut.fragments.MainFragment;
import net.nullsum.audinaut.service.MusicService;
import net.nullsum.audinaut.service.MusicServiceFactory;
import net.nullsum.audinaut.util.ImageLoader;
import net.nullsum.audinaut.util.SilentBackgroundTask;
import net.nullsum.audinaut.view.UpdateView;

import java.util.List;

public class EntryInfiniteGridAdapter extends EntryGridAdapter {
    public static final int VIEW_TYPE_LOADING = 4;

    private String type;
    private String extra;
    private int size;

    private boolean loading = false;
    private boolean allLoaded = false;

    public EntryInfiniteGridAdapter(Context context, List<Entry> entries, ImageLoader imageLoader, boolean largeCell) {
        super(context, entries, imageLoader, largeCell);
    }

    @Override
    public UpdateView.UpdateViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        if (viewType == VIEW_TYPE_LOADING) {
            View progress = LayoutInflater.from(context).inflate(R.layout.tab_progress, null);
            progress.setVisibility(View.VISIBLE);
            return new UpdateView.UpdateViewHolder(progress);
        }

        return super.onCreateViewHolder(parent, viewType);
    }

    @Override
    public int getItemViewType(int position) {
        if (isLoadingView(position)) {
            return VIEW_TYPE_LOADING;
        }

        return super.getItemViewType(position);
    }

    @Override
    public void onBindViewHolder(UpdateView.UpdateViewHolder holder, int position) {
        if (!isLoadingView(position)) {
            super.onBindViewHolder(holder, position);
        }
    }

    @Override
    public int getItemCount() {
        int size = super.getItemCount();

        if (!allLoaded) {
            size++;
        }

        return size;
    }

    public void setData(String type, String extra, int size) {
        this.type = type;
        this.extra = extra;
        this.size = size;

        if (super.getItemCount() < size) {
            allLoaded = true;
        }
    }

    public void loadMore() {
        if (loading || allLoaded) {
            return;
        }
        loading = true;

        new SilentBackgroundTask<Void>(context) {
            private List<Entry> newData;

            @Override
            protected Void doInBackground() throws Throwable {
                newData = cacheInBackground();
                return null;
            }

            @Override
            protected void done(Void result) {
                appendCachedData(newData);
                loading = false;

                if (newData.size() < size) {
                    allLoaded = true;
                    notifyDataSetChanged();
                }
            }
        }.execute();
    }

    private List<Entry> cacheInBackground() throws Exception {
        MusicService service = MusicServiceFactory.getMusicService(context);
        MusicDirectory result;
        int offset = sections.get(0).size();
        if ("genres".equals(type) || "years".equals(type)) {
            result = service.getAlbumList(type, extra, size, offset, false, context, null);
        } else if ("genres".equals(type) || "genres-songs".equals(type)) {
            result = service.getSongsByGenre(extra, size, offset, context, null);
        } else if (type.contains(MainFragment.SONGS_LIST_PREFIX)) {
            result = service.getSongList(type, size, offset, context, null);
        } else {
            result = service.getAlbumList(type, size, offset, false, context, null);
        }
        return result.getChildren();
    }

    private void appendCachedData(List<Entry> newData) {
        if (newData.size() > 0) {
            int start = sections.get(0).size();
            sections.get(0).addAll(newData);
            this.notifyItemRangeInserted(start, newData.size());
        }
    }

    private boolean isLoadingView(int position) {
        return !allLoaded && position >= sections.get(0).size();
    }
}