Sample MediaItemConverter for google cast

MediaQueueItemMapper.kt

private const val KEY_EPISODE = "episode"
class MediaQueueItemMapper @Inject constructor(
    private val gson: Gson,
    private val mediaItemMapper: MediaItemMapper // Our custom implementation
) : MediaItemConverter {
    override fun toMediaQueueItem(mediaItem: MediaItem): MediaQueueItem {
        val episode = mediaItem.playbackProperties?.tag as Episode
        return toMediaQueueItem(episode)
    }

    override fun toMediaItem(mediaQueueItem: MediaQueueItem): MediaItem {
        return mediaItemMapper.toMediaItem(gson.fromJson(mediaQueueItem.customData.getString(KEY_EPISODE), Episode::class.java))
    }

    private fun toMediaQueueItem(episode: Episode): MediaQueueItem = with(episode) {
        val mediaMetaData = MediaMetadata(MediaMetadata.MEDIA_TYPE_AUDIOBOOK_CHAPTER)
        mediaMetaData.putString(MediaMetadata.KEY_SUBTITLE, author)
        mediaMetaData.putString(MediaMetadata.KEY_TITLE, title)
        val coverImage = if (coverImageWithFallback != null) {
            coverImageWithFallback
        } else {
            BuildConfig.CAST_FALLBACK_COVER_URL
        }
        mediaMetaData.addImage(WebImage(Uri.parse(coverImage)))
        val rawStreamUrl = Uri.parse(this.streamUrl).buildUrl()
        val mediaInfo = MediaInfo.Builder(rawStreamUrl).apply {
            setStreamType(MediaInfo.STREAM_TYPE_BUFFERED)
            setMetadata(mediaMetaData)
        }.build()

        val mediaQueueItem = MediaQueueItem.Builder(mediaInfo).build()
        mediaQueueItem.customData = JSONObject()
        mediaQueueItem.customData.put(KEY_EPISODE, gson.toJson(episode))
        return mediaQueueItem
    }
}