import pymod
import sys
import numpy as np

mp3 = pymod._ysynth_mp3_open(sys.argv[1])
samplerate, channels = pymod._ysynth_mp3_get_format(mp3)
print "Samplerate:", samplerate, "Channels:", channels

x = pymod._ysynth_init(samplerate, channels)
first_time = True

def play_mp3(channels):
    """
    Play contents of MP3 file.
    """
    
    global first_time

    if first_time:
        print "First time callback occurred"
        print "Array shape is: %s" % str(channels.shape)
        first_time = False

    next_chunk = pymod._ysynth_mp3_read(mp3, channels.shape[0])
    next_chunk = np.minimum(np.maximum(next_chunk, -1.0), 1.0)
    # Using 32767.5 as a factor causes overflow, we need to fix this
    # in the most uniformly distributed way possible
    np.round(next_chunk * 32767, 0, out=channels)

    return

pymod._ysynth_set_callback(x, play_mp3)