#!/usr/bin/python
import sys, os, re, struct
DEBUGGING = True
CURRENT = {'db': '', 'title': '', 'location': '', 'album': '', 'artist': ''}
def main(itunesdb):
 db = readall(itunesdb)
 CURRENT['db'] = itunesdb
 i = 0
 while i < len(db):
  tag = db[i:i + 4]
  taglength = struct.unpack('<L', db[i + 4:i + 8])[0]
  recordlength = struct.unpack('<L', db[i + 8:i + 12])[0]
  record = db[i:i + recordlength]
  if tag == 'mhod':
   i += recordlength
   rectype = struct.unpack('<L', record[12:16])[0]
   debug((rectype, recordlength))
   if rectype == 1 and recordlength > 40:
    strlen = struct.unpack('<L', record[28:32])[0]
    string = record[40:].decode('utf-16').encode('latin1', 'replace')
    debug(('rectype 1', string))
    if CURRENT['title']: raise Exception, 'two titles for same mhit'
    else: CURRENT['title'] = string
   elif rectype == 3 and recordlength > 40:
    strlen = struct.unpack('<L', record[28:32])[0]
    string = record[40:].decode('utf-16').encode('latin1', 'replace')
    if CURRENT['album']: raise Exception, 'two album titles for same mhit'
    else: CURRENT['album'] = string
   elif rectype == 22 and recordlength > 40:
    strlen = struct.unpack('<L', record[28:32])[0]
    string = record[40:].decode('utf-16').encode('latin1', 'replace')
    if CURRENT['artist']: raise Exception, 'two album artists for same mhit'
    else: CURRENT['artist'] = string
   elif rectype == 2 and recordlength > 40:
    strlen = struct.unpack('<L', record[28:32])[0]
    string = record[40:].decode('utf-16').encode('latin1', 'replace')
    debug(('rectype 2', string, record.encode('hex')))
    if CURRENT['location']: raise Exception, 'two locations for same mhit'
    elif not CURRENT['title']: raise Exception, 'no title for mhit'
    else: symlink(translate(string), CURRENT['title'])
   else:
    debug('skipping record type %d' % rectype)
    debug((tag, taglength, recordlength, record.encode('hex'), record))
  elif tag == 'mhit':
   #debug((tag, taglength, recordlength, record.encode('hex'), record))
   for songdata in ['title', 'location', 'album', 'artist']:
    CURRENT[songdata] = ''
   i += taglength
  elif tag == 'mhyp':
   print >>sys.stderr, 'reached end of songs, found playlist'
   sys.exit(0)
  else:
   debug('skipping tag %s' % tag)
   i += taglength
def debug(message):
 if DEBUGGING:
  print >>sys.stderr, message
def readall(filename):
 input = open(filename, 'rb')
 data = input.read()
 input.close()
 return data
def translate(path):
 debug('translating %s into real path' % path)
 basedir = os.path.dirname(os.path.dirname(os.path.abspath(CURRENT['db'])))
 subdir = path.replace(':', os.sep)
 basedir, check = os.path.split(basedir)
 if check != subdir.split(os.sep)[1]:
  raise Exception, 'directory mismatch'
 else:
  debug('joining %s to %s' % (basedir, subdir))
  dirname = os.path.join(basedir, subdir.lstrip(os.sep))
  debug(('dirname', dirname))
  return dirname
def symlink(path, title):
 debug('linking %s to %s' % (path, title))
 outfile = os.path.join(CURRENT['artist'], CURRENT['album'], CURRENT['title'])
 outdir = '/tmp/ipod'
 if not os.path.isdir(outdir):
  os.mkdir(outdir)
 outpath = os.path.join(outdir, outfile) + os.path.splitext(path)[1]
 if not os.path.isdir(os.path.dirname(outpath)):
  os.makedirs(os.path.dirname(outpath))
 debug('output to %s' % outpath)
 try:
  os.symlink(path, outpath)
 except OSError:
  debug('ignoring duplicate')
  pass
if __name__ == '__main__':
 main((sys.argv + [os.path.join(
  os.getenv('HOME', '/var/mobile'),
  'Media/iTunes_Control/iTunes/iTunesDB')])[1])