NewPipe-app-android/app/src/main/java/org/schabi/newpipe/util/ListHelper.java

package org.schabi.newpipe.util;

import static org.schabi.newpipe.extractor.ServiceList.YouTube;

import android.content.Context;
import android.content.SharedPreferences;
import android.content.res.Resources;
import android.net.ConnectivityManager;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.StringRes;
import androidx.core.content.ContextCompat;
import androidx.preference.PreferenceManager;

import org.schabi.newpipe.R;
import org.schabi.newpipe.extractor.MediaFormat;
import org.schabi.newpipe.extractor.stream.AudioStream;
import org.schabi.newpipe.extractor.stream.AudioTrackType;
import org.schabi.newpipe.extractor.stream.DeliveryMethod;
import org.schabi.newpipe.extractor.stream.Stream;
import org.schabi.newpipe.extractor.stream.VideoStream;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Objects;
import java.util.Set;
import java.util.function.Predicate;
import java.util.stream.Collectors;

public final class ListHelper {
    // Video format in order of quality. 0=lowest quality, n=highest quality
    private static final List<MediaFormat> VIDEO_FORMAT_QUALITY_RANKING =
            List.of(MediaFormat.v3GPP, MediaFormat.WEBM, MediaFormat.MPEG_4);

    // Audio format in order of quality. 0=lowest quality, n=highest quality
    private static final List<MediaFormat> AUDIO_FORMAT_QUALITY_RANKING =
            List.of(MediaFormat.MP3, MediaFormat.WEBMA, MediaFormat.M4A);
    // Audio format in order of efficiency. 0=least efficient, n=most efficient
    private static final List<MediaFormat> AUDIO_FORMAT_EFFICIENCY_RANKING =
            List.of(MediaFormat.MP3, MediaFormat.M4A, MediaFormat.WEBMA);
    // Use a Set for better performance
    private static final Set<String> HIGH_RESOLUTION_LIST = Set.of("1440p", "2160p");
    // Audio track types in order of priority. 0=lowest, n=highest
    private static final List<AudioTrackType> AUDIO_TRACK_TYPE_RANKING =
            List.of(AudioTrackType.DESCRIPTIVE, AudioTrackType.DUBBED, AudioTrackType.ORIGINAL);
    // Audio track types in order of priority when descriptive audio is preferred.
    private static final List<AudioTrackType> AUDIO_TRACK_TYPE_RANKING_DESCRIPTIVE =
            List.of(AudioTrackType.ORIGINAL, AudioTrackType.DUBBED, AudioTrackType.DESCRIPTIVE);

    /**
     * List of supported YouTube Itag ids.
     * The original order is kept.
     * @see {@link org.schabi.newpipe.extractor.services.youtube.ItagItem#ITAG_LIST}
     */
    private static final List<Integer> SUPPORTED_ITAG_IDS =
            List.of(
                    17, 36, // video v3GPP
                    18, 34, 35, 59, 78, 22, 37, 38, // video MPEG4
                    43, 44, 45, 46, // video webm
                    171, 172, 139, 140, 141, 249, 250, 251, // audio
                    160, 133, 134, 135, 212, 136, 298, 137, 299, 266, // video only
                    278, 242, 243, 244, 245, 246, 247, 248, 271, 272, 302, 303, 308, 313, 315
            );

    private ListHelper() { }

    /**
     * @param context      Android app context
     * @param videoStreams list of the video streams to check
     * @return index of the video stream with the default index
     * @see #getDefaultResolutionIndex(String, String, MediaFormat, List)
     */
    public static int getDefaultResolutionIndex(final Context context,
                                                final List<VideoStream> videoStreams) {
        final String defaultResolution = computeDefaultResolution(context,
                R.string.default_resolution_key, R.string.default_resolution_value);
        return getDefaultResolutionWithDefaultFormat(context, defaultResolution, videoStreams);
    }

    /**
     * @param context           Android app context
     * @param videoStreams      list of the video streams to check
     * @param defaultResolution the default resolution to look for
     * @return index of the video stream with the default index
     * @see #getDefaultResolutionIndex(String, String, MediaFormat, List)
     */
    public static int getResolutionIndex(final Context context,
                                         final List<VideoStream> videoStreams,
                                         final String defaultResolution) {
        return getDefaultResolutionWithDefaultFormat(context, defaultResolution, videoStreams);
    }

    /**
     * @param context      Android app context
     * @param videoStreams list of the video streams to check
     * @return index of the video stream with the default index
     * @see #getDefaultResolutionIndex(String, String, MediaFormat, List)
     */
    public static int getPopupDefaultResolutionIndex(final Context context,
                                                     final List<VideoStream> videoStreams) {
        final String defaultResolution = computeDefaultResolution(context,
                R.string.default_popup_resolution_key, R.string.default_popup_resolution_value);
        return getDefaultResolutionWithDefaultFormat(context, defaultResolution, videoStreams);
    }

    /**
     * @param context           Android app context
     * @param videoStreams      list of the video streams to check
     * @param defaultResolution the default resolution to look for
     * @return index of the video stream with the default index
     * @see #getDefaultResolutionIndex(String, String, MediaFormat, List)
     */
    public static int getPopupResolutionIndex(final Context context,
                                              final List<VideoStream> videoStreams,
                                              final String defaultResolution) {
        return getDefaultResolutionWithDefaultFormat(context, defaultResolution, videoStreams);
    }

    public static int getDefaultAudioFormat(final Context context,
                                            final List<AudioStream> audioStreams) {
        return getAudioIndexByHighestRank(audioStreams,
                getAudioTrackComparator(context).thenComparing(getAudioFormatComparator(context)));
    }

    public static int getDefaultAudioTrackGroup(final Context context,
                                                final List<List<AudioStream>> groupedAudioStreams) {
        if (groupedAudioStreams == null || groupedAudioStreams.isEmpty()) {
            return -1;
        }

        final Comparator<AudioStream> cmp = getAudioTrackComparator(context);
        final List<AudioStream> highestRanked = groupedAudioStreams.stream()
                .max((o1, o2) -> cmp.compare(o1.get(0), o2.get(0)))
                .orElse(null);
        return groupedAudioStreams.indexOf(highestRanked);
    }

    public static int getAudioFormatIndex(final Context context,
                                          final List<AudioStream> audioStreams,
                                          @Nullable final String trackId) {
        if (trackId != null) {
            for (int i = 0; i < audioStreams.size(); i++) {
                final AudioStream s = audioStreams.get(i);
                if (s.getAudioTrackId() != null
                        && s.getAudioTrackId().equals(trackId)) {
                    return i;
                }
            }
        }
        return getDefaultAudioFormat(context, audioStreams);
    }

    /**
     * Return a {@link Stream} list which uses the given delivery method from a {@link Stream}
     * list.
     *
     * @param streamList     the original {@link Stream stream} list
     * @param deliveryMethod the {@link DeliveryMethod delivery method}
     * @param <S>            the item type's class that extends {@link Stream}
     * @return a {@link Stream stream} list which uses the given delivery method
     */
    @NonNull
    public static <S extends Stream> List<S> getStreamsOfSpecifiedDelivery(
            @Nullable final List<S> streamList,
            final DeliveryMethod deliveryMethod) {
        return getFilteredStreamList(streamList,
                stream -> stream.getDeliveryMethod() == deliveryMethod);
    }

    /**
     * Return a {@link Stream} list which only contains URL streams and non-torrent streams.
     *
     * @param streamList the original stream list
     * @param <S>        the item type's class that extends {@link Stream}
     * @return a stream list which only contains URL streams and non-torrent streams
     */
    @NonNull
    public static <S extends Stream> List<S> getUrlAndNonTorrentStreams(
            @Nullable final List<S> streamList) {
        return getFilteredStreamList(streamList,
                stream -> stream.isUrl() && stream.getDeliveryMethod() != DeliveryMethod.TORRENT);
    }

    /**
     * Return a {@link Stream} list which only contains streams which can be played by the player.
     *
     * <p>
     * Some formats are not supported, see {@link #SUPPORTED_ITAG_IDS} for more details.
     * Torrent streams are also removed, because they cannot be retrieved, like OPUS streams using
     * HLS as their delivery method, since they are not supported by ExoPlayer.
     * </p>
     *
     * @param <S>        the item type's class that extends {@link Stream}
     * @param streamList the original stream list
     * @param serviceId  the service ID from which the streams' list comes from
     * @return a stream list which only contains streams that can be played the player
     */
    @NonNull
    public static <S extends Stream> List<S> getPlayableStreams(
            @Nullable final List<S> streamList, final int serviceId) {
        final int youtubeServiceId = YouTube.getServiceId();
        return getFilteredStreamList(streamList,
                stream -> stream.getDeliveryMethod() != DeliveryMethod.TORRENT
                        && (stream.getDeliveryMethod() != DeliveryMethod.HLS
                        || stream.getFormat() != MediaFormat.OPUS)
                        && (serviceId != youtubeServiceId
                        || stream.getItagItem() == null
                        || SUPPORTED_ITAG_IDS.contains(stream.getItagItem().id)));
    }

    /**
     * Join the two lists of video streams (video_only and normal videos),
     * and sort them according with default format chosen by the user.
     *
     * @param context                the context to search for the format to give preference
     * @param videoStreams           the normal videos list
     * @param videoOnlyStreams       the video-only stream list
     * @param ascendingOrder         true -> smallest to greatest | false -> greatest to smallest
     * @param preferVideoOnlyStreams if video-only streams should preferred when both video-only
     *                               streams and normal video streams are available
     * @return the sorted list
     */
    @NonNull
    public static List<VideoStream> getSortedStreamVideosList(
            @NonNull final Context context,
            @Nullable final List<VideoStream> videoStreams,
            @Nullable final List<VideoStream> videoOnlyStreams,
            final boolean ascendingOrder,
            final boolean preferVideoOnlyStreams) {
        final SharedPreferences preferences =
                PreferenceManager.getDefaultSharedPreferences(context);

        final boolean showHigherResolutions = preferences.getBoolean(
                context.getString(R.string.show_higher_resolutions_key), false);
        final MediaFormat defaultFormat = getDefaultFormat(context,
                R.string.default_video_format_key, R.string.default_video_format_value);

        return getSortedStreamVideosList(defaultFormat, showHigherResolutions, videoStreams,
                videoOnlyStreams, ascendingOrder, preferVideoOnlyStreams);
    }

    /**
     * Get a sorted list containing a set of default resolution info
     * and additional resolution info if showHigherResolutions is true.
     *
     * @param resources the resources to get the resolutions from
     * @param defaultResolutionKey the settings key of the default resolution
     * @param additionalResolutionKey the settings key of the additional resolutions
     * @param showHigherResolutions if higher resolutions should be included in the sorted list
     * @return a sorted list containing the default and maybe additional resolutions
     */
    public static List<String> getSortedResolutionList(
            final Resources resources,
            final int defaultResolutionKey,
            final int additionalResolutionKey,
            final boolean showHigherResolutions) {
        final List<String> resolutions = new ArrayList<>(Arrays.asList(
                resources.getStringArray(defaultResolutionKey)));
        if (!showHigherResolutions) {
            return resolutions;
        }
        final List<String> additionalResolutions = Arrays.asList(
                resources.getStringArray(additionalResolutionKey));
        // keep "best resolution" at the top
        resolutions.addAll(1, additionalResolutions);
        return resolutions;
    }

    public static boolean isHighResolutionSelected(final String selectedResolution,
                                             final int additionalResolutionKey,
                                             final Resources resources) {
        return Arrays.asList(resources.getStringArray(
                        additionalResolutionKey))
                .contains(selectedResolution);
    }

    /**
     * Filter the list of audio streams and return a list with the preferred stream for
     * each audio track. Streams are sorted with the preferred language in the first position.
     *
     * @param context      the context to search for the track to give preference
     * @param audioStreams the list of audio streams
     * @return the sorted, filtered list
     */
    public static List<AudioStream> getFilteredAudioStreams(
            @NonNull final Context context,
            @Nullable final List<AudioStream> audioStreams) {
        if (audioStreams == null) {
            return Collections.emptyList();
        }

        final HashMap<String, AudioStream> collectedStreams = new HashMap<>();

        final Comparator<AudioStream> cmp = getAudioFormatComparator(context);

        for (final AudioStream stream : audioStreams) {
            if (stream.getDeliveryMethod() == DeliveryMethod.TORRENT
                    || (stream.getDeliveryMethod() == DeliveryMethod.HLS
                    && stream.getFormat() == MediaFormat.OPUS)) {
                continue;
            }

            final String trackId = Objects.toString(stream.getAudioTrackId(), "");

            final AudioStream presentStream = collectedStreams.get(trackId);
            if (presentStream == null || cmp.compare(stream, presentStream) > 0) {
                collectedStreams.put(trackId, stream);
            }
        }

        // Filter unknown audio tracks if there are multiple tracks
        if (collectedStreams.size() > 1) {
            collectedStreams.remove("");
        }

        // Sort collected streams by name
        return collectedStreams.values().stream().sorted(getAudioTrackNameComparator(context))
                .collect(Collectors.toList());
    }

    /**
     * Group the list of audioStreams by their track ID and sort the resulting list by track name.
     *
     * @param context      app context to get track names for sorting
     * @param audioStreams list of audio streams
     * @return list of audio streams lists representing individual tracks
     */
    public static List<List<AudioStream>> getGroupedAudioStreams(
            @NonNull final Context context,
            @Nullable final List<AudioStream> audioStreams) {
        if (audioStreams == null) {
            return Collections.emptyList();
        }

        final HashMap<String, List<AudioStream>> collectedStreams = new HashMap<>();

        for (final AudioStream stream : audioStreams) {
            final String trackId = Objects.toString(stream.getAudioTrackId(), "");
            if (collectedStreams.containsKey(trackId)) {
                collectedStreams.get(trackId).add(stream);
            } else {
                final List<AudioStream> list = new ArrayList<>();
                list.add(stream);
                collectedStreams.put(trackId, list);
            }
        }

        // Filter unknown audio tracks if there are multiple tracks
        if (collectedStreams.size() > 1) {
            collectedStreams.remove("");
        }

        // Sort tracks alphabetically, sort track streams by quality
        final Comparator<AudioStream> nameCmp = getAudioTrackNameComparator(context);
        final Comparator<AudioStream> formatCmp = getAudioFormatComparator(context);

        return collectedStreams.values().stream()
                .sorted((o1, o2) -> nameCmp.compare(o1.get(0), o2.get(0)))
                .map(streams -> streams.stream().sorted(formatCmp).collect(Collectors.toList()))
                .collect(Collectors.toList());
    }

    /*//////////////////////////////////////////////////////////////////////////
    // Utils
    //////////////////////////////////////////////////////////////////////////*/

    /**
     * Get a filtered stream list, by using Java 8 Stream's API and the given predicate.
     *
     * @param streamList          the stream list to filter
     * @param streamListPredicate the predicate which will be used to filter streams
     * @param <S>                 the item type's class that extends {@link Stream}
     * @return a new stream list filtered using the given predicate
     */
    private static <S extends Stream> List<S> getFilteredStreamList(
            @Nullable final List<S> streamList,
            final Predicate<S> streamListPredicate) {
        if (streamList == null) {
            return Collections.emptyList();
        }

        return streamList.stream()
                .filter(streamListPredicate)
                .collect(Collectors.toList());
    }

    private static String computeDefaultResolution(@NonNull final Context context, final int key,
                                                   final int value) {
        final SharedPreferences preferences =
                PreferenceManager.getDefaultSharedPreferences(context);

        // Load the preferred resolution otherwise the best available
        String resolution = preferences != null
                ? preferences.getString(context.getString(key), context.getString(value))
                : context.getString(R.string.best_resolution_key);

        final String maxResolution = getResolutionLimit(context);
        if (maxResolution != null
                && (resolution.equals(context.getString(R.string.best_resolution_key))
                || compareVideoStreamResolution(maxResolution, resolution) < 1)) {
            resolution = maxResolution;
        }
        return resolution;
    }

    /**
     * Return the index of the default stream in the list, that will be sorted in the process, based
     * on the parameters defaultResolution and defaultFormat.
     *
     * @param defaultResolution the default resolution to look for
     * @param bestResolutionKey key of the best resolution
     * @param defaultFormat     the default format to look for
     * @param videoStreams      a mutable list of the video streams to check (it will be sorted in
     *                          place)
     * @return index of the default resolution&format in the sorted videoStreams
     */
    static int getDefaultResolutionIndex(final String defaultResolution,
                                         final String bestResolutionKey,
                                         final MediaFormat defaultFormat,
                                         @Nullable final List<VideoStream> videoStreams) {
        if (videoStreams == null || videoStreams.isEmpty()) {
            return -1;
        }

        sortStreamList(videoStreams, false);
        if (defaultResolution.equals(bestResolutionKey)) {
            return 0;
        }

        final int defaultStreamIndex =
                getVideoStreamIndex(defaultResolution, defaultFormat, videoStreams);

        // this is actually an error,
        // but maybe there is really no stream fitting to the default value.
        if (defaultStreamIndex == -1) {
            return 0;
        }
        return defaultStreamIndex;
    }

    /**
     * Join the two lists of video streams (video_only and normal videos),
     * and sort them according with default format chosen by the user.
     *
     * @param defaultFormat          format to give preference
     * @param showHigherResolutions  show >1080p resolutions
     * @param videoStreams           normal videos list
     * @param videoOnlyStreams       video only stream list
     * @param ascendingOrder         true -> smallest to greatest | false -> greatest to smallest
     * @param preferVideoOnlyStreams if video-only streams should preferred when both video-only
     *                               streams and normal video streams are available
     * @return the sorted list
     */
    @NonNull
    static List<VideoStream> getSortedStreamVideosList(
            @Nullable final MediaFormat defaultFormat,
            final boolean showHigherResolutions,
            @Nullable final List<VideoStream> videoStreams,
            @Nullable final List<VideoStream> videoOnlyStreams,
            final boolean ascendingOrder,
            final boolean preferVideoOnlyStreams
    ) {
        // Determine order of streams
        // The last added list is preferred
        final List<List<VideoStream>> videoStreamsOrdered =
                preferVideoOnlyStreams
                        ? Arrays.asList(videoStreams, videoOnlyStreams)
                        : Arrays.asList(videoOnlyStreams, videoStreams);

        final List<VideoStream> allInitialStreams = videoStreamsOrdered.stream()
                // Ignore lists that are null
                .filter(Objects::nonNull)
                .flatMap(List::stream)
                // Filter out higher resolutions (or not if high resolutions should always be shown)
                .filter(stream -> showHigherResolutions
                        || !HIGH_RESOLUTION_LIST.contains(stream.getResolution()
                        // Replace any frame rate with nothing
                        .replaceAll("p\\d+$", "p")))
                .collect(Collectors.toList());

        final HashMap<String, VideoStream> hashMap = new HashMap<>();
        // Add all to the hashmap
        for (final VideoStream videoStream : allInitialStreams) {
            hashMap.put(videoStream.getResolution(), videoStream);
        }

        // Override the values when the key == resolution, with the defaultFormat
        for (final VideoStream videoStream : allInitialStreams) {
            if (videoStream.getFormat() == defaultFormat) {
                hashMap.put(videoStream.getResolution(), videoStream);
            }
        }

        // Return the sorted list
        return sortStreamList(new ArrayList<>(hashMap.values()), ascendingOrder);
    }

    /**
     * Sort the streams list depending on the parameter ascendingOrder;
     * <p>
     * It works like that:<br>
     * - Take a string resolution, remove the letters, replace "0p60" (for 60fps videos) with "1"
     * and sort by the greatest:<br>
     * <blockquote><pre>
     *      720p     ->  720
     *      720p60   ->  721
     *      360p     ->  360
     *      1080p    ->  1080
     *      1080p60  ->  1081
     * <br>
     * ascendingOrder  ? 360 < 720 < 721 < 1080 < 1081
     * !ascendingOrder ? 1081 < 1080 < 721 < 720 < 360</pre></blockquote>
     *
     * @param videoStreams   list that the sorting will be applied
     * @param ascendingOrder true -> smallest to greatest | false -> greatest to smallest
     * @return The sorted list (same reference as parameter videoStreams)
     */
    private static List<VideoStream> sortStreamList(final List<VideoStream> videoStreams,
                                                    final boolean ascendingOrder) {
        // Compares the quality of two video streams.
        final Comparator<VideoStream> comparator = Comparator.nullsLast(Comparator
                .comparing(VideoStream::getResolution, ListHelper::compareVideoStreamResolution)
                .thenComparingInt(s -> VIDEO_FORMAT_QUALITY_RANKING.indexOf(s.getFormat())));
        Collections.sort(videoStreams, ascendingOrder ? comparator : comparator.reversed());
        return videoStreams;
    }

    /**
     * Get the audio-stream from the list with the highest rank, depending on the comparator.
     * Format will be ignored if it yields no results.
     *
     * @param audioStreams List of audio streams
     * @param comparator   The comparator used for determining the max/best/highest ranked value
     * @return Index of audio stream that produces the highest ranked result or -1 if not found
     */
    static int getAudioIndexByHighestRank(@Nullable final List<AudioStream> audioStreams,
                                          final Comparator<AudioStream> comparator) {
        if (audioStreams == null || audioStreams.isEmpty()) {
            return -1;
        }

        final AudioStream highestRankedAudioStream = audioStreams.stream()
                .max(comparator).orElse(null);

        return audioStreams.indexOf(highestRankedAudioStream);
    }

    /**
     * Locates a possible match for the given resolution and format in the provided list.
     *
     * <p>In this order:</p>
     *
     * <ol>
     * <li>Find a format and resolution match</li>
     * <li>Find a format and resolution match and ignore the refresh</li>
     * <li>Find a resolution match</li>
     * <li>Find a resolution match and ignore the refresh</li>
     * <li>Find a resolution just below the requested resolution and ignore the refresh</li>
     * <li>Give up</li>
     * </ol>
     *
     * @param targetResolution the resolution to look for
     * @param targetFormat     the format to look for
     * @param videoStreams     the available video streams
     * @return the index of the preferred video stream
     */
    static int getVideoStreamIndex(@NonNull final String targetResolution,
                                   final MediaFormat targetFormat,
                                   @NonNull final List<VideoStream> videoStreams) {
        int fullMatchIndex = -1;
        int fullMatchNoRefreshIndex = -1;
        int resMatchOnlyIndex = -1;
        int resMatchOnlyNoRefreshIndex = -1;
        int lowerResMatchNoRefreshIndex = -1;
        final String targetResolutionNoRefresh = targetResolution.replaceAll("p\\d+$", "p");

        for (int idx = 0; idx < videoStreams.size(); idx++) {
            final MediaFormat format = targetFormat == null
                    ? null
                    : videoStreams.get(idx).getFormat();
            final String resolution = videoStreams.get(idx).getResolution();
            final String resolutionNoRefresh = resolution.replaceAll("p\\d+$", "p");

            if (format == targetFormat && resolution.equals(targetResolution)) {
                fullMatchIndex = idx;
            }

            if (format == targetFormat && resolutionNoRefresh.equals(targetResolutionNoRefresh)) {
                fullMatchNoRefreshIndex = idx;
            }

            if (resMatchOnlyIndex == -1 && resolution.equals(targetResolution)) {
                resMatchOnlyIndex = idx;
            }

            if (resMatchOnlyNoRefreshIndex == -1
                    && resolutionNoRefresh.equals(targetResolutionNoRefresh)) {
                resMatchOnlyNoRefreshIndex = idx;
            }

            if (lowerResMatchNoRefreshIndex == -1 && compareVideoStreamResolution(
                    resolutionNoRefresh, targetResolutionNoRefresh) < 0) {
                lowerResMatchNoRefreshIndex = idx;
            }
        }

        if (fullMatchIndex != -1) {
            return fullMatchIndex;
        }
        if (fullMatchNoRefreshIndex != -1) {
            return fullMatchNoRefreshIndex;
        }
        if (resMatchOnlyIndex != -1) {
            return resMatchOnlyIndex;
        }
        if (resMatchOnlyNoRefreshIndex != -1) {
            return resMatchOnlyNoRefreshIndex;
        }
        return lowerResMatchNoRefreshIndex;
    }

    /**
     * Fetches the desired resolution or returns the default if it is not found.
     * The resolution will be reduced if video chocking is active.
     *
     * @param context           Android app context
     * @param defaultResolution the default resolution
     * @param videoStreams      the list of video streams to check
     * @return the index of the preferred video stream
     */
    private static int getDefaultResolutionWithDefaultFormat(@NonNull final Context context,
                                                             final String defaultResolution,
                                                             final List<VideoStream> videoStreams) {
        final MediaFormat defaultFormat = getDefaultFormat(context,
                R.string.default_video_format_key, R.string.default_video_format_value);
        return getDefaultResolutionIndex(defaultResolution,
                context.getString(R.string.best_resolution_key), defaultFormat, videoStreams);
    }

    @Nullable
    private static MediaFormat getDefaultFormat(@NonNull final Context context,
                                                @StringRes final int defaultFormatKey,
                                                @StringRes final int defaultFormatValueKey) {
        final SharedPreferences preferences =
                PreferenceManager.getDefaultSharedPreferences(context);

        final String defaultFormat = context.getString(defaultFormatValueKey);
        final String defaultFormatString = preferences.getString(
                context.getString(defaultFormatKey),
                defaultFormat
        );

        return getMediaFormatFromKey(context, defaultFormatString);
    }

    @Nullable
    private static MediaFormat getMediaFormatFromKey(@NonNull final Context context,
                                                     @NonNull final String formatKey) {
        MediaFormat format = null;
        if (formatKey.equals(context.getString(R.string.video_webm_key))) {
            format = MediaFormat.WEBM;
        } else if (formatKey.equals(context.getString(R.string.video_mp4_key))) {
            format = MediaFormat.MPEG_4;
        } else if (formatKey.equals(context.getString(R.string.video_3gp_key))) {
            format = MediaFormat.v3GPP;
        } else if (formatKey.equals(context.getString(R.string.audio_webm_key))) {
            format = MediaFormat.WEBMA;
        } else if (formatKey.equals(context.getString(R.string.audio_m4a_key))) {
            format = MediaFormat.M4A;
        }
        return format;
    }

    private static int compareVideoStreamResolution(@NonNull final String r1,
                                                    @NonNull final String r2) {
        try {
            final int res1 = Integer.parseInt(r1.replaceAll("0p\\d+$", "1")
                    .replaceAll("[^\\d.]", ""));
            final int res2 = Integer.parseInt(r2.replaceAll("0p\\d+$", "1")
                    .replaceAll("[^\\d.]", ""));
            return res1 - res2;
        } catch (final NumberFormatException e) {
            // Consider the first one greater because we don't know if the two streams are
            // different or not (a NumberFormatException was thrown so we don't know the resolution
            // of one stream or of all streams)
            return 1;
        }
    }

    static boolean isLimitingDataUsage(@NonNull final Context context) {
        return getResolutionLimit(context) != null;
    }

    /**
     * The maximum resolution allowed.
     *
     * @param context App context
     * @return maximum resolution allowed or null if there is no maximum
     */
    private static String getResolutionLimit(@NonNull final Context context) {
        String resolutionLimit = null;
        if (isMeteredNetwork(context)) {
            final SharedPreferences preferences =
                    PreferenceManager.getDefaultSharedPreferences(context);
            final String defValue = context.getString(R.string.limit_data_usage_none_key);
            final String value = preferences.getString(
                    context.getString(R.string.limit_mobile_data_usage_key), defValue);
            resolutionLimit = defValue.equals(value) ? null : value;
        }
        return resolutionLimit;
    }

    /**
     * The current network is metered (like mobile data)?
     *
     * @param context App context
     * @return {@code true} if connected to a metered network
     */
    public static boolean isMeteredNetwork(@NonNull final Context context) {
        final ConnectivityManager manager =
                ContextCompat.getSystemService(context, ConnectivityManager.class);
        if (manager == null || manager.getActiveNetworkInfo() == null) {
            return false;
        }

        return manager.isActiveNetworkMetered();
    }

    /**
     * Get a {@link Comparator} to compare {@link AudioStream}s by their format and bitrate.
     *
     * <p>The preferred stream will be ordered last.</p>
     *
     * @param context app context
     * @return Comparator
     */
    private static Comparator<AudioStream> getAudioFormatComparator(
            final @NonNull Context context) {
        final MediaFormat defaultFormat = getDefaultFormat(context,
                R.string.default_audio_format_key, R.string.default_audio_format_value);
        return getAudioFormatComparator(defaultFormat, isLimitingDataUsage(context));
    }

    /**
     * Get a {@link Comparator} to compare {@link AudioStream}s by their format and bitrate.
     *
     * <p>The preferred stream will be ordered last.</p>
     *
     * @param defaultFormat  the default format to look for
     * @param limitDataUsage choose low bitrate audio stream
     * @return Comparator
     */
    static Comparator<AudioStream> getAudioFormatComparator(
            @Nullable final MediaFormat defaultFormat, final boolean limitDataUsage) {
        final List<MediaFormat> formatRanking = limitDataUsage
                ? AUDIO_FORMAT_EFFICIENCY_RANKING : AUDIO_FORMAT_QUALITY_RANKING;

        Comparator<AudioStream> bitrateComparator =
                Comparator.comparingInt(AudioStream::getAverageBitrate);
        if (limitDataUsage) {
            bitrateComparator = bitrateComparator.reversed();
        }

        return Comparator.comparing(AudioStream::getFormat, (o1, o2) -> {
            if (defaultFormat != null) {
                return Boolean.compare(o1 == defaultFormat, o2 == defaultFormat);
            }
            return 0;
        }).thenComparing(bitrateComparator).thenComparingInt(
                stream -> formatRanking.indexOf(stream.getFormat()));
    }

    /**
     * Get a {@link Comparator} to compare {@link AudioStream}s by their tracks.
     *
     * <p>Tracks will be compared this order:</p>
     * <ol>
     * <li>If {@code preferOriginalAudio}: use original audio</li>
     * <li>Language matches {@code preferredLanguage}</li>
     * <li>
     *     Track type ranks highest in this order:
     *     <i>Original</i> > <i>Dubbed</i> > <i>Descriptive</i>
     *     <p>If {@code preferDescriptiveAudio}:
     *     <i>Descriptive</i> > <i>Dubbed</i> > <i>Original</i></p>
     * </li>
     * <li>Language is English</li>
     * </ol>
     *
     * <p>The preferred track will be ordered last.</p>
     *
     * @param context App context
     * @return Comparator
     */
    private static Comparator<AudioStream> getAudioTrackComparator(
            @NonNull final Context context) {
        final SharedPreferences preferences =
                PreferenceManager.getDefaultSharedPreferences(context);
        final Locale preferredLanguage = Localization.getPreferredLocale(context);
        final boolean preferOriginalAudio =
                preferences.getBoolean(context.getString(R.string.prefer_original_audio_key),
                        false);
        final boolean preferDescriptiveAudio =
                preferences.getBoolean(context.getString(R.string.prefer_descriptive_audio_key),
                        false);

        return getAudioTrackComparator(preferredLanguage, preferOriginalAudio,
                preferDescriptiveAudio);
    }

    /**
     * Get a {@link Comparator} to compare {@link AudioStream}s by their tracks.
     *
     * <p>Tracks will be compared this order:</p>
     * <ol>
     * <li>If {@code preferOriginalAudio}: use original audio</li>
     * <li>Language matches {@code preferredLanguage}</li>
     * <li>
     *     Track type ranks highest in this order:
     *     <i>Original</i> > <i>Dubbed</i> > <i>Descriptive</i>
     *     <p>If {@code preferDescriptiveAudio}:
     *     <i>Descriptive</i> > <i>Dubbed</i> > <i>Original</i></p>
     * </li>
     * <li>Language is English</li>
     * </ol>
     *
     * <p>The preferred track will be ordered last.</p>
     *
     * @param preferredLanguage      Preferred audio stream language
     * @param preferOriginalAudio    Get the original audio track regardless of its language
     * @param preferDescriptiveAudio Prefer the descriptive audio track if available
     * @return Comparator
     */
    static Comparator<AudioStream> getAudioTrackComparator(
            final Locale preferredLanguage,
            final boolean preferOriginalAudio,
            final boolean preferDescriptiveAudio) {
        final String langCode = preferredLanguage.getISO3Language();
        final List<AudioTrackType> trackTypeRanking = preferDescriptiveAudio
                ? AUDIO_TRACK_TYPE_RANKING_DESCRIPTIVE : AUDIO_TRACK_TYPE_RANKING;

        return Comparator.comparing(AudioStream::getAudioTrackType, (o1, o2) -> {
                    if (preferOriginalAudio) {
                        return Boolean.compare(
                                o1 == AudioTrackType.ORIGINAL, o2 == AudioTrackType.ORIGINAL);
                    }
                    return 0;
                }).thenComparing(AudioStream::getAudioLocale,
                        Comparator.nullsFirst(Comparator.comparing(
                                locale -> locale.getISO3Language().equals(langCode))))
                .thenComparing(AudioStream::getAudioTrackType,
                        Comparator.nullsFirst(Comparator.comparingInt(trackTypeRanking::indexOf)))
                .thenComparing(AudioStream::getAudioLocale,
                        Comparator.nullsFirst(Comparator.comparing(
                                locale -> locale.getISO3Language().equals(
                                        Locale.ENGLISH.getISO3Language()))));
    }

    /**
     * Get a {@link Comparator} to compare {@link AudioStream}s by their languages and track types
     * for alphabetical sorting.
     *
     * @param context app context for localization
     * @return Comparator
     */
    private static Comparator<AudioStream> getAudioTrackNameComparator(
            @NonNull final Context context) {
        final Locale appLoc = Localization.getAppLocale(context);

        return Comparator.comparing(AudioStream::getAudioLocale, Comparator.nullsLast(
                        Comparator.comparing(locale -> locale.getDisplayName(appLoc))))
                .thenComparing(AudioStream::getAudioTrackType);
    }
}