DroidFS/app/src/main/java/sushi/hardcore/droidfs/file_viewers/MediaPlayer.kt

package sushi.hardcore.droidfs.file_viewers

import android.view.WindowManager
import com.google.android.exoplayer2.*
import com.google.android.exoplayer2.extractor.DefaultExtractorsFactory
import com.google.android.exoplayer2.source.MediaSource
import com.google.android.exoplayer2.source.ProgressiveMediaSource
import sushi.hardcore.droidfs.ConstValues
import sushi.hardcore.droidfs.R
import sushi.hardcore.droidfs.widgets.CustomAlertDialogBuilder

abstract class MediaPlayer: FileViewerActivity() {
    private lateinit var player: ExoPlayer

    override fun viewFile() {
        initializePlayer()
    }

    abstract fun bindPlayer(player: ExoPlayer)
    protected open fun onPlaylistIndexChanged() {}
    protected open fun onPlayerReady() {}

    private fun createMediaSource(filePath: String): MediaSource {
        val dataSourceFactory = GocryptfsDataSource.Factory(gocryptfsVolume, filePath)
        return ProgressiveMediaSource.Factory(dataSourceFactory, DefaultExtractorsFactory())
            .createMediaSource(MediaItem.fromUri(ConstValues.fakeUri))
    }

    private fun initializePlayer(){
        player = ExoPlayer.Builder(this).build()
        bindPlayer(player)
        createPlaylist()
        for (e in mappedPlaylist) {
            player.addMediaSource(createMediaSource(e.fullPath))
        }
        player.repeatMode = Player.REPEAT_MODE_ALL
        player.seekToDefaultPosition(currentPlaylistIndex)
        player.playWhenReady = true
        player.addListener(object : Player.Listener{
            override fun onPlayerStateChanged(playWhenReady: Boolean, playbackState: Int) {
                if (playbackState == Player.STATE_READY) {
                    onPlayerReady()
                }
            }
            override fun onPlayerError(error: PlaybackException) {
                CustomAlertDialogBuilder(this@MediaPlayer, themeValue)
                        .setTitle(R.string.error)
                        .setMessage(getString(R.string.playing_failed, error.errorCodeName))
                        .setCancelable(false)
                        .setPositiveButton(R.string.ok) { _, _ -> goBackToExplorer()}
                        .show()
            }
            override fun onIsPlayingChanged(isPlaying: Boolean) {
                if (isPlaying){
                    window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
                } else {
                    window.clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
                }
            }
            override fun onPositionDiscontinuity(reason: Int) {
                if (player.currentMediaItemIndex != currentPlaylistIndex) {
                    playlistNext(player.currentMediaItemIndex == (currentPlaylistIndex+1) % mappedPlaylist.size)
                    onPlaylistIndexChanged()
                }
            }
        })
        player.prepare()
    }

    override fun onDestroy() {
        super.onDestroy()
        if (::player.isInitialized) {
            player.release()
        }
    }
}