/*
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

package com.facebook.imagepipeline.producers;

import android.net.Uri;

import com.facebook.imagepipeline.image.EncodedImage;

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

/**
 * Network fetcher that uses the simplest Android stack.
 *
 * <p> Apps requiring more sophisticated networking should implement their own
 * {@link NetworkFetcher}.
 */
public class HttpUrlConnectionNetworkFetcher extends BaseNetworkFetcher<FetchState> {

  private static final int NUM_NETWORK_THREADS = 3;

  private final ExecutorService mExecutorService;

  public HttpUrlConnectionNetworkFetcher() {
    mExecutorService = Executors.newFixedThreadPool(NUM_NETWORK_THREADS);
  }

  @Override
  public FetchState createFetchState(Consumer<EncodedImage> consumer, ProducerContext context) {
    return new FetchState(consumer, context);
  }

  @Override
  public void fetch(final FetchState fetchState, final Callback callback) {
    final Future<?> future = mExecutorService.submit(
        new Runnable() {
          @Override
          public void run() {
            HttpURLConnection connection = null;
            Uri uri = fetchState.getUri();
            String scheme = uri.getScheme();
            String uriString = fetchState.getUri().toString();
            while (true) {
              String nextUriString;
              String nextScheme;
              InputStream is;
              try {
                URL url = new URL(uriString);
                connection = (HttpURLConnection) url.openConnection();
                nextUriString = connection.getHeaderField("Location");
                nextScheme = (nextUriString == null) ? null : Uri.parse(nextUriString).getScheme();
                if (nextUriString == null || nextScheme.equals(scheme)) {
                  is = connection.getInputStream();
                  callback.onResponse(is, -1);
                  break;
                }
                uriString = nextUriString;
                scheme = nextScheme;
              } catch (Exception e) {
                callback.onFailure(e);
                break;
              } finally {
                if (connection != null) {
                  connection.disconnect();
                }
              }
          }

          }
        });
    fetchState.getContext().addCallbacks(
        new BaseProducerContextCallbacks() {
          @Override
          public void onCancellationRequested() {
            if (future.cancel(false)) {
              callback.onCancellation();
            }
          }
        });
  }
}