import mpv

def _complexGraph(tracks):
    graph = ""
    for i, enabled in tracks.items():
        graph += f"[aid{i}]volume={"1.0" if enabled else "0.0"}[a{i}];"
    graph += "[a1][a2][a3][a4][a5][a6]amix=inputs=6:"
    graph += "duration=longest:normalize=0[ao]"
    return graph

def _simpleGraph():
    return (
        "[aid1]volume=1.0[a1];"
        "[a1]amix=inputs=1:"
        "duration=longest:normalize=1[ao]"
    )

class Player:
    VOCAL_TRACK = 1
    GUITAR_TRACK = 2
    BASS_TRACK = 3
    PIANO_TRACK =4
    DRUM_TRACK = 5
    OTHER_TRACK = 6

    def __init__(self):
        self._player = mpv.MPV(ao="jack")
        self._player.loop = "inf"
        self._player.lavfi_complex = _simpleGraph()
        self._playingStateCallback = self._dummyCallback
        self._volumeCallback = self._dummyCallback
        self._player.observe_property("pause", lambda name, value: self._playingStateCallback())
        self._player.observe_property("volume", lambda name, value: self._volumeCallback())
        self._player.observe_property("track-list/count", lambda name, value: self._updateGraph())
        self._tracks = {
            self.VOCAL_TRACK: True,
            self.GUITAR_TRACK: True,
            self.BASS_TRACK: True,
            self.PIANO_TRACK: True,
            self.DRUM_TRACK: True,
            self.OTHER_TRACK: True 
        }

    def __del__(self):
        self._player.close()

    def _dummyCallback(self):
        pass

    def _updateGraph(self):
        if self.tracksSupported():
            self._player.lavfi_complex = _complexGraph(self._tracks)
        else:
            self._player.lavfi_complex = _simpleGraph()

    def play(self):
        self._player.pause = False

    def pause(self):
        self._player.pause = True

    def isPlaying(self):
        return not self._player.pause

    def setPlaybackRate(self, rate):
        self._player.speed = rate

    def getPlaybackRate(self):
        return self._player.speed

    def setPlaybackPosition(self, position):
        self._player.percent_pos = position * 100

    def getPlaybackPosition(self):
        return float(self._player.percent_pos or 0.0) / 100.0

    def setPlaybackVolume(self, volume):
        self._player.volume = int(volume * 100)

    def getPlaybackVolume(self):
        return float(self._player.volume) / 100.0

    def setCurrentSong(self, path):
        self.pause()
        self._player.play(str(path))

    def setPlayingStateChangedCallback(self, callback):
        self._playingStateCallback = callback

    def setPlaybackVolumeChangedCallback(self, callback):
        self._volumeCallback = callback

    def tracksSupported(self):
        return len(self._player.track_list) == 6

    def trackEnabled(self, trackId):
        return self._tracks[trackId]

    def setTrackEnabled(self, trackId, enable):
        self._tracks[trackId] = enable
        self._updateGraph()