#! /usr/bin/env python

import sys
import os
import os.path
import re
import tagpy
import tagpy.mpeg
import tagpy.ogg

from optparse import OptionParser

songs = sys.argv[1:]

patterns = [
 "${artist:7}-${album:7}/${track}-${title}.${ext}",
 "${artist}/${album}/${track}-${title}.${ext}",
 ]
mix_pattern = "AAAMIX/${artist:7}-${title}.${ext}"

opt_parse = OptionParser(usage="%prog [options] root_path")
opt_parse.add_option("-p", "--pattern", dest="pattern",
                     help="Use PATTERN as the rename pattern")
opt_parse.add_option("-m", "--use-mix", action="store_true", dest="use_mix",
                     help="Use aaamix directory")
opt_parse.add_option("-M", "--no-use-mix", action="store_false", dest="use_mix",
                     help="Do not use aaamix directory")

(options, remaining_args) = opt_parse.parse_args()

if options.pattern is not None:
    pattern = patterns[int(options.pattern)]
else:
    for i, p in enumerate(patterns):
        print i, p
    print

    pattern = patterns[int(raw_input("Select pattern: "))]
if options.use_mix is not None:
    use_mix = options.use_mix
else:
    use_mix = raw_input("Use AAAMIX directory? [n]y?") == "y"

def canonical_ext(song):
    if isinstance(song, tagpy.mpeg.File):
        aprops = song.audioProperties()
        if aprops is None:
            raise ValueError, "MPEG track %s has no audio properties" % song.name()
        return "mp%d" % aprops.layer
    elif isinstance(song, tagpy.ogg.File):
        return "ogg"
    else:
        raise ValueError, "unknown track type"

def is_directory(name):
    dirstat = os.stat(name)
    import stat
    return stat.S_ISDIR(dirstat.st_mode)

def force_us_ascii(str):
    result = ""
    for i in str:
        if 32 <= ord(i) < 128:
            result += chr(ord(i))
        else:
            result += "_"
    return result

def makedirs(name, mode=0777):
    # stolen and modified from os
    """makedirs(path [, mode=0777])

    Super-mkdir; create a leaf directory and all intermediate ones.
    Works like mkdir, except that any intermediate path segment (not
    just the rightmost) will be created if it does not exist.  This is
    recursive.

    """
    head, tail = os.path.split(name)
    while not tail:
        head, tail = os.path.split(head)
    if head and tail and not os.path.exists(head):
        makedirs(head, mode)
    try:
        os.mkdir(name, mode)
    except OSError:
        pass

def make_fn_suitable(str):
    return force_us_ascii(str
                          .replace("/", "_")
                          .replace("?", "_")
                          .replace("*", "_")
                          .replace("&", "_")
                          .replace(":", "_")
                          .replace("\"", "_")
                          .replace("\'", "_")
                          .replace("<", "_")
                          .replace(">", "_")
                          )

def expand_pattern(pattern, song):
    tag = song.tag()
    if tag is None:
        return None

    expr = re.compile(r"\$\{([a-z]+)(\:[0-9]+)?\}")

    def variable_function(match):
        meta_id = match.group(1)

        if meta_id == "artist": result =  tag.artist
        elif meta_id == "album": result =  tag.album
        elif meta_id == "title": result =  tag.title
        elif meta_id == "ext": result =  canonical_ext(song)
        elif meta_id == "track": result =  "%02d" % tag.track
        else: 
            raise ValueError, "invalid variable in pattern: "+meta_id

        if len(match.groups()) == 2 and match.group(2):
            result = result[:int(match.group(2)[1:])]
        return make_fn_suitable(result).strip()

    return expr.sub(variable_function, pattern)

def get_new_dir_and_name(pattern, song):
    dest_name = expand_pattern(pattern, song)
    if dest_name is None:
        return None

    dest_dir = os.path.dirname(dest_name).lower()
    dest_basename = os.path.basename(dest_name)
    return dest_dir, os.path.join(dest_dir, dest_basename)

# walk directory tree
all_songs = []
for dirpath, dirnames, filenames in os.walk(remaining_args[0]):
    all_songs += [os.path.join(dirpath, filename) for filename in filenames]

# find out all "canonical" renames, i.e. without mix directory
dest_dir_counts = {}
renames = []

for source_name in all_songs:
    try:
        song = tagpy.FileRef(source_name).file()
    except ValueError:
        print "WARNING: Not a media file:\n  %s" % source_name
        continue

    dir_and_name = get_new_dir_and_name(pattern, song)
    if dir_and_name is not None:
        dest_dir, dest_name = get_new_dir_and_name(pattern, song)

        renames.append((source_name, dest_name, dest_dir))
        dest_dir_counts[dest_dir] = 1 + dest_dir_counts.setdefault(dest_dir, 0)

# judge mix directory and perform moves
for source_name, dest_name, dest_dir in renames:
    if use_mix and dest_dir_counts[dest_dir] == 1:
        song = tagpy.FileRef(source_name).file()
        dest_dir, dest_name = get_new_dir_and_name(mix_pattern, song)

    try:
        if not is_directory(dest_dir):
            print "WARNING: %s exists, but is not a directory, skipping\n  %s" % \
                  (dest_dir, dest_name)
            continue
    except OSError:
        makedirs(dest_dir)

    try:
      os.rename(source_name, dest_name)
    except OSError, e:
      print "Couldn't rename `%s' to `%s': %s" % (source_name, dest_name, e)