package de.danoeh.antennapod.fragment;

import android.content.Context;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.view.View;
import de.danoeh.antennapod.adapter.DownloadLogAdapter;
import de.danoeh.antennapod.feed.EventDistributor;
import de.danoeh.antennapod.service.download.DownloadStatus;
import de.danoeh.antennapod.storage.DBReader;

import java.util.List;

/**
 * Shows the download log
 */
public class DownloadLogFragment extends ListFragment {

    private List<DownloadStatus> downloadLog;
    private DownloadLogAdapter adapter;

    private boolean viewsCreated = false;
    private boolean itemsLoaded = false;

    @Override
    public void onStart() {
        super.onStart();
        EventDistributor.getInstance().register(contentUpdate);
        startItemLoader();
    }

    @Override
    public void onStop() {
        super.onStop();
        EventDistributor.getInstance().unregister(contentUpdate);
        stopItemLoader();
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        viewsCreated = true;
        if (itemsLoaded) {
            onFragmentLoaded();
        }
    }

    private void onFragmentLoaded() {
        if (adapter == null) {
            adapter = new DownloadLogAdapter(getActivity(), itemAccess);
            setListAdapter(adapter);
        }
        setListShown(true);
        adapter.notifyDataSetChanged();

    }

    private DownloadLogAdapter.ItemAccess itemAccess = new DownloadLogAdapter.ItemAccess() {

        @Override
        public int getCount() {
            return (downloadLog != null) ? downloadLog.size() : 0;
        }

        @Override
        public DownloadStatus getItem(int position) {
            return (downloadLog != null) ? downloadLog.get(position) : null;
        }
    };

    private EventDistributor.EventListener contentUpdate = new EventDistributor.EventListener() {

        @Override
        public void update(EventDistributor eventDistributor, Integer arg) {
            if ((arg & EventDistributor.DOWNLOADLOG_UPDATE) != 0) {
                startItemLoader();
            }
        }
    };

    private ItemLoader itemLoader;

    private void startItemLoader() {
        if (itemLoader != null) {
            itemLoader.cancel(true);
        }
        itemLoader = new ItemLoader();
        itemLoader.execute();
    }

    private void stopItemLoader() {
        if (itemLoader != null) {
            itemLoader.cancel(true);
        }
    }

    private class ItemLoader extends AsyncTask<Void, Void, List<DownloadStatus>> {

        @Override
        protected void onPostExecute(List<DownloadStatus> downloadStatuses) {
            super.onPostExecute(downloadStatuses);
            if (downloadStatuses != null) {
                downloadLog = downloadStatuses;
                itemsLoaded = true;
                if (viewsCreated) {
                    onFragmentLoaded();
                }
            }
        }

        @Override
        protected List<DownloadStatus> doInBackground(Void... params) {
            Context context = getActivity();
            if (context != null) {
                return DBReader.getDownloadLog(context);
            }
            return null;
        }
    }
}