view-mate/app-glasses/src/main/kotlin/pw/binom/viewmate/glasses/MovieController.kt

package pw.binom.viewmate.glasses

import android.content.Context
import android.os.Handler
import android.os.Looper
import com.google.android.exoplayer2.MediaItem
import com.google.android.exoplayer2.SimpleExoPlayer
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.flow.asStateFlow
import pw.binom.viewmate.core.MediaCommand
import pw.binom.viewmate.core.protocol.PlayVideo

/**
 * Держатель плеера фильма: создаёт/освобождает SimpleExoPlayer,
 * выполняет команды из WS-протокола. Сам плеер создаётся только по PlayVideo.
 */
class MovieController(private val context: Context) {

    private val _movieActive = MutableStateFlow(false)
    val movieActive: StateFlow<Boolean> = _movieActive.asStateFlow()

    private val _title = MutableStateFlow<String?>(null)
    val title: StateFlow<String?> = _title.asStateFlow()

    private var _player: SimpleExoPlayer? = null
    val player: SimpleExoPlayer? get() = _player

    private val mainHandler = Handler(Looper.getMainLooper())

    fun playVideo(msg: PlayVideo) {
        mainHandler.post {
            val player = _player ?: SimpleExoPlayer.Builder(context).build().also {
                _player = it
                log("glasses", "SimpleExoPlayer создан")
            }
            _title.value = msg.title
            log("glasses", "PlayVideo: «${msg.title}» — ${msg.videoUrl}")
            player.setMediaItem(MediaItem.fromUri(msg.videoUrl))
            player.prepare()
            player.seekTo(msg.startPositionMs)
            player.playWhenReady = true
            _movieActive.value = true
        }
    }

    fun applyMediaCommand(command: MediaCommand, seekMs: Long) {
        mainHandler.post {
            val player = _player ?: run {
                log("glasses", "MediaCommand $command проигнорирован: плеер не активен")
                return@post
            }
            when (command) {
                MediaCommand.PLAY -> player.play()

                MediaCommand.PAUSE -> player.pause()

                MediaCommand.TOGGLE -> {
                    if (player.isPlaying) player.pause() else player.play()
                }

                MediaCommand.SEEK_FORWARD -> {
                    val target = player.currentPosition + seekMs
                    player.seekTo(target)
                }

                MediaCommand.SEEK_BACKWARD -> {
                    val target = (player.currentPosition - seekMs).coerceAtLeast(0L)
                    player.seekTo(target)
                }

                // Звук — на телефоне, переключение аудио-дорожек очкам не нужно.
                MediaCommand.NEXT_AUDIO, MediaCommand.PREV_AUDIO -> {
                    log("glasses", "MediaCommand $command игнорируется (звук на телефоне)")
                }

                MediaCommand.CLOSE -> close()
            }
        }
    }

    fun close() {
        mainHandler.post {
            val player = _player
            _player = null
            if (player != null) {
                log("glasses", "CLOSE: плеер остановлен и освобождён")
                player.playWhenReady = false
                player.stop()
                player.release()
            }
            _movieActive.value = false
            _title.value = null
        }
    }

    /** Читать ТОЛЬКО с главного потока. */
    fun playbackPosition(): Pair<Long, Boolean> {
        val player = _player ?: return 0L to false
        return player.currentPosition to player.isPlaying
    }
}