package de.danoeh.antennapod.fragment;

import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.GridView;
import android.widget.ProgressBar;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import de.danoeh.antennapod.R;
import de.danoeh.antennapod.activity.OnlineFeedViewActivity;
import de.danoeh.antennapod.adapter.itunes.ItunesAdapter;
import de.danoeh.antennapod.discovery.ItunesTopListLoader;
import de.danoeh.antennapod.discovery.PodcastSearchResult;
import io.reactivex.disposables.Disposable;

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

/**
 * Searches iTunes store for top podcasts and displays results in a list.
 */
public class DiscoveryFragment extends Fragment {

    private static final String TAG = "ItunesSearchFragment";

    /**
     * Adapter responsible with the search results.
     */
    private ItunesAdapter adapter;
    private GridView gridView;
    private ProgressBar progressBar;
    private TextView txtvError;
    private Button butRetry;
    private TextView txtvEmpty;

    /**
     * List of podcasts retreived from the search.
     */
    private List<PodcastSearchResult> searchResults;
    private List<PodcastSearchResult> topList;
    private Disposable disposable;

    /**
     * Replace adapter data with provided search results from SearchTask.
     * @param result List of Podcast objects containing search results
     */
    private void updateData(List<PodcastSearchResult> result) {
        this.searchResults = result;
        adapter.clear();
        if (result != null && result.size() > 0) {
            gridView.setVisibility(View.VISIBLE);
            txtvEmpty.setVisibility(View.GONE);
            for (PodcastSearchResult p : result) {
                adapter.add(p);
            }
            adapter.notifyDataSetInvalidated();
        } else {
            gridView.setVisibility(View.GONE);
            txtvEmpty.setVisibility(View.VISIBLE);
        }
    }

    public DiscoveryFragment() {
        // Required empty public constructor
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setHasOptionsMenu(true);
    }

    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View root = inflater.inflate(R.layout.fragment_itunes_search, container, false);
        ((AppCompatActivity) getActivity()).setSupportActionBar(root.findViewById(R.id.toolbar));
        gridView = root.findViewById(R.id.gridView);
        adapter = new ItunesAdapter(getActivity(), new ArrayList<>());
        gridView.setAdapter(adapter);

        //Show information about the podcast when the list item is clicked
        gridView.setOnItemClickListener((parent, view1, position, id) -> {
            PodcastSearchResult podcast = searchResults.get(position);
            if (podcast.feedUrl == null) {
                return;
            }
            Intent intent = new Intent(getActivity(), OnlineFeedViewActivity.class);
            intent.putExtra(OnlineFeedViewActivity.ARG_FEEDURL, podcast.feedUrl);
            startActivity(intent);
        });
        progressBar = root.findViewById(R.id.progressBar);
        txtvError = root.findViewById(R.id.txtvError);
        butRetry = root.findViewById(R.id.butRetry);
        txtvEmpty = root.findViewById(android.R.id.empty);

        loadToplist();

        return root;
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        if (disposable != null) {
            disposable.dispose();
        }
        adapter = null;
    }

    private void loadToplist() {
        if (disposable != null) {
            disposable.dispose();
        }
        gridView.setVisibility(View.GONE);
        txtvError.setVisibility(View.GONE);
        butRetry.setVisibility(View.GONE);
        txtvEmpty.setVisibility(View.GONE);
        progressBar.setVisibility(View.VISIBLE);

        ItunesTopListLoader loader = new ItunesTopListLoader(getContext());
        disposable = loader.loadToplist(25).subscribe(podcasts -> {
            progressBar.setVisibility(View.GONE);
            topList = podcasts;
            updateData(topList);
        }, error -> {
                Log.e(TAG, Log.getStackTraceString(error));
                progressBar.setVisibility(View.GONE);
                txtvError.setText(error.toString());
                txtvError.setVisibility(View.VISIBLE);
                butRetry.setOnClickListener(v -> loadToplist());
                butRetry.setVisibility(View.VISIBLE);
            });
    }
}