class Player():
    STOPPED = 0
    PLAYING = 1
    PAUSED = 2

    def __init__(self):
        self.state = Player.STOPPED
        self.rate = 1.0
        self.position = 0.0
        self.volume = 1.0
        self.currentSong = None
        self.playingStateChangedCallback = None
        self.playbackVolumeChangedCallback = None

    def play(self):
        previousState = self.state
        self.state = Player.PLAYING
        if previousState != Player.PLAYING:
            self.playingStateChangedCallback()

    def stop(self):
        previousState = self.state
        self.state = Player.STOPPED
        if previousState != Player.STOPPED:
            self.playingStateChangedCallback()

    def pause(self):
        previousState = self.state
        self.state = Player.PAUSED
        if previousState != Player.PAUSED:
            self.playingStateChangedCallback()

    def isPlaying(self):
        return self.state == Player.PLAYING

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

    def getPlaybackRate(self):
        return self.rate

    def setPlaybackPosition(self, position):
        self.position = position

    def getPlaybackPosition(self):
        return self.position

    def setPlaybackVolume(self, volume):
        changed = self.volume != volume
        self.volume = volume
        if changed:
            self.playbackVolumeChangedCallback()

    def getPlaybackVolume(self):
        return self.volume

    def setCurrentSong(self, path):
        self.currentSong = path

    def setPlayingStateChangedCallback(self, callback):
        self.playingStateChangedCallback = callback
    
    def simulatePlayingStateChanged(self):
        self.playingStateChangedCallback()

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

    def simulatePlaybackVolumeChanged(self):
        self.playbackVolumeChangedCallback()