trackorder.py

#!/usr/bin/env python

import os
import sys
from lxml import etree
from operator import itemgetter


metadata_dir = '.metadata'   

def is_album_dir(d):
    return len([f for f in os.listdir(d) if f[-4:] == ".mp3"])

def sort_by_values(d):
    return sorted(d.iteritems(), key=itemgetter(1))

def usage():
    print >> sys.stderr, "Usage: %s ALBUM_PATH" % sys.argv[0]
    sys.exit(1)

if __name__ == '__main__':
    if len(sys.argv) != 2:
        usage()
    album_dir = sys.argv[1]
    if not os.path.isdir(album_dir) or \
            not os.path.isdir(os.path.join(album_dir, metadata_dir)) or \
            not is_album_dir(album_dir):
        usage()
    trackmap = dict.fromkeys([f for f in os.listdir(album_dir) if f != metadata_dir])
    for track in trackmap:
        mdfile = os.path.join(album_dir, metadata_dir, track.replace('.mp3', '.xml'))
        doc = etree.parse(mdfile, etree.XMLParser(recover=True))
        try:
            trackmap[track] = int(doc.find('originalTrackNumber').text)
        except AttributeError:
            trackmap[track] = 1
    ordered_tracks =  [os.path.join(album_dir, t) for (t, i) in sort_by_values(trackmap)]
    print "\n".join(ordered_tracks)