#!/usr/bin/env python3

# Builtin libraries
import sys
import struct
import urllib.request, urllib.parse, urllib.error
import os
import hashlib
import subprocess
import collections
import errno
import argparse
import shutil
import re
import tempfile
import signal

# External libraries
try:
    import mutagen
except ImportError:
    mutagen = None

audio_ext = (".mp3", ".m4a", ".m4b", ".m4p", ".aa", ".wav")
list_ext = (".pls", ".m3u")
def make_dir_if_absent(path):
    try:
        os.makedirs(path)
    except OSError as exc:
        if exc.errno != errno.EEXIST:
            raise

def raises_unicode_error(str):
    try:
        str.encode('latin-1')
        return False
    except (UnicodeEncodeError, UnicodeDecodeError):
        return True

def hash_error_unicode(item):
    item_bytes = item.encode('utf-8')
    return "".join(["{0:02X}".format(ord(x)) for x in reversed(hashlib.md5(item_bytes).hexdigest()[:8])])

def validate_unicode(path):
    path_list = path.split('/')
    last_raise = False
    for i in range(len(path_list)):
        if raises_unicode_error(path_list[i]):
            path_list[i] = hash_error_unicode(path_list[i])
            last_raise = True
        else:
            last_raise = False
    extension = os.path.splitext(path)[1].lower()
    return "/".join(path_list) + (extension if last_raise and extension in audio_ext else '')

def exec_exists_in_path(command):
    with open(os.devnull, 'w') as FNULL:
        try:
            with open(os.devnull, 'r') as RFNULL:
                subprocess.call([command], stdout=FNULL, stderr=subprocess.STDOUT, stdin=RFNULL)
                return True
        except OSError as e:
            return False

def splitpath(path):
    return path.split(os.sep)

def get_relpath(path, basepath):
    commonprefix = os.sep.join(os.path.commonprefix(list(map(splitpath, [path, basepath]))))
    return os.path.relpath(path, commonprefix)

def is_path_prefix(prefix, path):
    return prefix == os.sep.join(os.path.commonprefix(list(map(splitpath, [prefix, path]))))

def group_tracks_by_id3_template(tracks, template):
    grouped_tracks_dict = {}
    template_vars = set(re.findall(r'{.*?}', template))
    for track in tracks:
        try:
            id3_dict = mutagen.File(track, easy=True)
        except:
            id3_dict = {}

        key = template
        single_var_present = False
        for var in template_vars:
            val = id3_dict.get(var[1:-1], [''])[0]
            if len(val) > 0:
                single_var_present = True
            key = key.replace(var, val)

        if single_var_present:
            if key not in grouped_tracks_dict:
                grouped_tracks_dict[key] = []
            grouped_tracks_dict[key].append(track)

    return sorted(grouped_tracks_dict.items())

class Text2Speech(object):
    valid_tts = {'pico2wave': True, 'RHVoice': True, 'espeak': True}

    @staticmethod
    def check_support():
        voiceoverAvailable = False

        # Check for pico2wave voiceover
        if not exec_exists_in_path("pico2wave"):
            Text2Speech.valid_tts['pico2wave'] = False
            print("Warning: pico2wave not found, voicever won't be generated using it.")
        else:
            voiceoverAvailable = True

        # Check for espeak voiceover
        if not exec_exists_in_path("espeak"):
            Text2Speech.valid_tts['espeak'] = False
            print("Warning: espeak not found, voicever won't be generated using it.")
        else:
            voiceoverAvailable = True

        # Check for Russian RHVoice voiceover
        if not exec_exists_in_path("RHVoice"):
            Text2Speech.valid_tts['RHVoice'] = False
            print("Warning: RHVoice not found, Russian voicever won't be generated.")
        else:
            voiceoverAvailable = True

        # Return if we at least found one voiceover program.
        # Otherwise this will result in silent voiceover for tracks and "Playlist N" for playlists.
        return voiceoverAvailable

    @staticmethod
    def text2speech(out_wav_path, text):
        # Skip voiceover generation if a track with the same name is used.
        # This might happen with "Track001" or "01. Intro" names for example.
        if os.path.isfile(out_wav_path):
            verboseprint("Using existing", out_wav_path)
            return True

        # ensure we deal with unicode later
        if not isinstance(text, str):
            text = str(text, 'utf-8')
        lang = Text2Speech.guess_lang(text)
        if lang == "ru-RU":
            return Text2Speech.rhvoice(out_wav_path, text)
        else:
            if Text2Speech.pico2wave(out_wav_path, text):
                return True
            elif Text2Speech.espeak(out_wav_path, text):
                return True
            else:
                return False

    # guess-language seems like an overkill for now
    @staticmethod
    def guess_lang(unicodetext):
        lang = 'en-GB'
        if re.search("[А-Яа-я]", unicodetext) is not None:
            lang = 'ru-RU'
        return lang

    @staticmethod
    def pico2wave(out_wav_path, unicodetext):
        if not Text2Speech.valid_tts['pico2wave']:
            return False
        subprocess.call(["pico2wave", "-l", "en-GB", "-w", out_wav_path, unicodetext])
        return True

    @staticmethod
    def espeak(out_wav_path, unicodetext):
        if not Text2Speech.valid_tts['espeak']:
            return False
        subprocess.call(["espeak", "-v", "english_rp", "-s", "150", "-w", out_wav_path, unicodetext])
        return True

    @staticmethod
    def rhvoice(out_wav_path, unicodetext):
        if not Text2Speech.valid_tts['RHVoice']:
            return False

        tmp_file = tempfile.NamedTemporaryFile(suffix=".wav", delete=False)
        tmp_file.close()

        proc = subprocess.Popen(["RHVoice", "--voice=Elena", "--variant=Russian", "--volume=100", "-o", tmp_file.name], stdin=subprocess.PIPE)
        proc.communicate(input=unicodetext.encode('utf-8'))
        # make a little bit louder to be comparable with pico2wave
        subprocess.call(["sox", tmp_file.name, out_wav_path, "norm"])

        os.remove(tmp_file.name)
        return True


class Record(object):

    def __init__(self, parent):
        self.parent = parent
        self._struct = collections.OrderedDict([])
        self._fields = {}
        self.track_voiceover = parent.track_voiceover
        self.playlist_voiceover = parent.playlist_voiceover
        self.rename = parent.rename
        self.trackgain = parent.trackgain

    def __getitem__(self, item):
        if item not in list(self._struct.keys()):
            raise KeyError
        return self._fields.get(item, self._struct[item][1])

    def __setitem__(self, item, value):
        self._fields[item] = value

    def construct(self):
        output = bytes()
        for i in list(self._struct.keys()):
            (fmt, default) = self._struct[i]
            output += struct.pack("<" + fmt, self._fields.get(i, default))
        return output

    def text_to_speech(self, text, dbid, playlist = False):
        if self.track_voiceover and not playlist or self.playlist_voiceover and playlist:
            # Create the voiceover wav file
            fn = ''.join(format(x, '02x') for x in reversed(dbid))
            path = os.path.join(self.base, "iPod_Control", "Speakable", "Tracks" if not playlist else "Playlists", fn + ".wav")
            return Text2Speech.text2speech(path, text)
        return False

    def path_to_ipod(self, filename):
        if os.path.commonprefix([os.path.abspath(filename), self.base]) != self.base:
            raise IOError("Cannot get Ipod filename, since file is outside the IPOD path")
        baselen = len(self.base)
        if self.base.endswith(os.path.sep):
            baselen -= 1
        ipodname = "/".join(os.path.abspath(filename)[baselen:].split(os.path.sep))
        return ipodname

    def ipod_to_path(self, ipodname):
        return os.path.abspath(os.path.join(self.base, os.path.sep.join(ipodname.split("/"))))

    @property
    def shuffledb(self):
        parent = self.parent
        while parent.__class__ != Shuffler:
            parent = parent.parent
        return parent

    @property
    def base(self):
        return self.shuffledb.path

    @property
    def tracks(self):
        return self.shuffledb.tracks

    @property
    def albums(self):
        return self.shuffledb.albums

    @property
    def artists(self):
        return self.shuffledb.artists

    @property
    def lists(self):
        return self.shuffledb.lists

class TunesSD(Record):
    def __init__(self, parent):
        Record.__init__(self, parent)
        self.track_header = TrackHeader(self)
        self.play_header = PlaylistHeader(self)
        self._struct = collections.OrderedDict([
                           ("header_id", ("4s", b"bdhs")), # shdb
                           ("unknown1", ("I", 0x02000003)),
                           ("total_length", ("I", 64)),
                           ("total_number_of_tracks", ("I", 0)),
                           ("total_number_of_playlists", ("I", 0)),
                           ("unknown2", ("Q", 0)),
                           ("max_volume", ("B", 0)),
                           ("voiceover_enabled", ("B", int(self.track_voiceover))),
                           ("unknown3", ("H", 0)),
                           ("total_tracks_without_podcasts", ("I", 0)),
                           ("track_header_offset", ("I", 64)),
                           ("playlist_header_offset", ("I", 0)),
                           ("unknown4", ("20s", b"\x00" * 20)),
                                               ])

    def construct(self):
        # The header is a fixed length, so no need to calculate it
        self.track_header.base_offset = 64
        track_header = self.track_header.construct()

        # The playlist offset will depend on the number of tracks
        self.play_header.base_offset = self.track_header.base_offset + len(track_header)
        play_header = self.play_header.construct(self.track_header.tracks)
        self["playlist_header_offset"] = self.play_header.base_offset

        self["total_number_of_tracks"] = self.track_header["number_of_tracks"]
        self["total_tracks_without_podcasts"] = self.track_header.total_tracks_without_podcasts()
        self["total_number_of_playlists"] = self.play_header["number_of_playlists"]

        output = Record.construct(self)
        return output + track_header + play_header

class TrackHeader(Record):
    def __init__(self, parent):
        self.base_offset = 0
        self.total_podcasts = 0
        Record.__init__(self, parent)
        self._struct = collections.OrderedDict([
                           ("header_id", ("4s", b"hths")), # shth
                           ("total_length", ("I", 0)),
                           ("number_of_tracks", ("I", 0)),
                           ("unknown1", ("Q", 0)),
                                             ])

    def construct(self):
        self["number_of_tracks"] = len(self.tracks)
        self["total_length"] = 20 + (len(self.tracks) * 4)
        output = Record.construct(self)

        # Construct the underlying tracks
        track_chunk = bytes()
        for i in self.tracks:
            track = Track(self)
            verboseprint("[*] Adding track", i)
            track.populate(i)
            if track.is_podcast:
                self.total_podcasts += 1
            output += struct.pack("I", self.base_offset + self["total_length"] + len(track_chunk))
            track_chunk += track.construct()
        return output + track_chunk

    def total_tracks_without_podcasts(self):
        return self["number_of_tracks"] - self.total_podcasts

class Track(Record):

    def __init__(self, parent):
        Record.__init__(self, parent)
        self.is_podcast = False
        self._struct = collections.OrderedDict([
                           ("header_id", ("4s", b"rths")), # shtr
                           ("header_length", ("I", 0x174)),
                           ("start_at_pos_ms", ("I", 0)),
                           ("stop_at_pos_ms", ("I", 0)),
                           ("volume_gain", ("I", int(self.trackgain))),
                           ("filetype", ("I", 1)),
                           ("filename", ("256s", b"\x00" * 256)),
                           ("bookmark", ("I", 0)),
                           ("dontskip", ("B", 1)),
                           ("remember", ("B", 0)),
                           ("unintalbum", ("B", 0)),
                           ("unknown", ("B", 0)),
                           ("pregap", ("I", 0x200)),
                           ("postgap", ("I", 0x200)),
                           ("numsamples", ("I", 0)),
                           ("unknown2", ("I", 0)),
                           ("gapless", ("I", 0)),
                           ("unknown3", ("I", 0)),
                           ("albumid", ("I", 0)),
                           ("track", ("H", 1)),
                           ("disc", ("H", 0)),
                           ("unknown4", ("Q", 0)),
                           ("dbid", ("8s", 0)),
                           ("artistid", ("I", 0)),
                           ("unknown5", ("32s", b"\x00" * 32)),
                           ])

    def populate(self, filename):
        self["filename"] = self.path_to_ipod(filename).encode('utf-8')

        if os.path.splitext(filename)[1].lower() in (".m4a", ".m4b", ".m4p", ".aa"):
            self["filetype"] = 2

        if "/iPod_Control/Podcasts/" in filename:
            self.is_podcast = True
            self["dontskip"] = 0
            self["remember"] = 1

        text = os.path.splitext(os.path.basename(filename))[0]

        # Try to get album and artist information with mutagen
        if mutagen:
            audio = None
            try:
                audio = mutagen.File(filename, easy = True)
            except:
                print("Error calling mutagen. Possible invalid filename/ID3Tags (hyphen in filename?)")
            if audio:
                if "Podcast" in audio.get("genre", ["Unknown"]):
                    self.is_podcast = True
                    self["dontskip"] = 0
                    self["remember"] = 1

                # Note: Rythmbox IPod plugin sets this value always 0.
                self["stop_at_pos_ms"] = int(audio.info.length * 1000)

                artist = audio.get("artist", ["Unknown"])[0]
                if artist in self.artists:
                    self["artistid"] = self.artists.index(artist)
                else:
                    self["artistid"] = len(self.artists)
                    self.artists.append(artist)

                album = audio.get("album", ["Unknown"])[0]
                if album in self.albums:
                    self["albumid"] = self.albums.index(album)
                else:
                    self["albumid"] = len(self.albums)
                    self.albums.append(album)

                if audio.get("title", "") and audio.get("artist", ""):
                    text = " - ".join(audio.get("title", "") + audio.get("artist", ""))

        # Handle the VoiceOverData
        if isinstance(text, str):
            text = text.encode('utf-8', 'ignore')
        self["dbid"] = hashlib.md5(text).digest()[:8]
        self.text_to_speech(text, self["dbid"])

class PlaylistHeader(Record):
    def __init__(self, parent):
        self.base_offset = 0
        Record.__init__(self, parent)
        self._struct = collections.OrderedDict([
                          ("header_id", ("4s", b"hphs")), #shph
                          ("total_length", ("I", 0)),
                          ("number_of_playlists", ("I", 0)),
                          ("number_of_non_podcast_lists", ("H", 65535)),
                          ("number_of_master_lists", ("2s", b"\x01\x00")),
                          ("number_of_non_audiobook_lists", ("2s", b"\xFF\xFF")),
                          ("unknown2", ("2s", b"\x00" * 2)),
                                              ])

    def construct(self, tracks):
        # Build the master list
        masterlist = Playlist(self)
        verboseprint("[+] Adding master playlist")
        masterlist.set_master(tracks)
        chunks = [masterlist.construct(tracks)]

        # Build all the remaining playlists
        playlistcount = 1
        podcastlistcount = 0
        for i in self.lists:
            playlist = Playlist(self)
            verboseprint("[+] Adding playlist", (i[0] if type(i) == type(()) else i))
            playlist.populate(i)
            construction = playlist.construct(tracks)
            if playlist["number_of_songs"] > 0:
                if playlist["listtype"] == 3:
                    podcastlistcount += 1
                playlistcount += 1
                chunks += [construction]
            else:
                print("Error: Playlist does not contain a single track. Skipping playlist.")

        self["number_of_playlists"] = playlistcount
        if podcastlistcount > 0:
            self["number_of_non_podcast_lists"] = playlistcount - podcastlistcount
        self["total_length"] = 0x14 + (self["number_of_playlists"] * 4)
        # Start the header

        output = Record.construct(self)
        offset = self.base_offset + self["total_length"]

        for i in range(len(chunks)):
            output += struct.pack("I", offset)
            offset += len(chunks[i])

        return output + b"".join(chunks)

class Playlist(Record):
    def __init__(self, parent):
        self.listtracks = []
        Record.__init__(self, parent)
        self._struct = collections.OrderedDict([
                          ("header_id", ("4s", b"lphs")), # shpl
                          ("total_length", ("I", 0)),
                          ("number_of_songs", ("I", 0)),
                          ("number_of_nonaudio", ("I", 0)),
                          ("dbid", ("8s", b"\x00" * 8)),
                          ("listtype", ("I", 2)),
                          ("unknown1", ("16s", b"\x00" * 16))
                                              ])

    def set_master(self, tracks):
        # By default use "All Songs" builtin voiceover (dbid all zero)
        # Else generate alternative "All Songs" to fit the speaker voice of other playlists
        if self.playlist_voiceover and (Text2Speech.valid_tts['pico2wave'] or Text2Speech.valid_tts['espeak']):
            self["dbid"] = hashlib.md5(b"masterlist").digest()[:8]
            self.text_to_speech("All songs", self["dbid"], True)
        self["listtype"] = 1
        self.listtracks = tracks

    def set_podcast(self):
        self["listtype"] = 3

    def populate_m3u(self, data):
        listtracks = []
        for i in data:
            if not i.startswith("#"):
                path = i.strip()
                if self.rename:
                    path = validate_unicode(path)
                listtracks.append(path)
        return listtracks

    def populate_pls(self, data):
        sorttracks = []
        for i in data:
            dataarr = i.strip().split("=", 1)
            if dataarr[0].lower().startswith("file"):
                num = int(dataarr[0][4:])
                filename = urllib.parse.unquote(dataarr[1]).strip()
                if filename.lower().startswith('file://'):
                    filename = filename[7:]
                if self.rename:
                    filename = validate_unicode(filename)
                sorttracks.append((num, filename))
        listtracks = [ x for (_, x) in sorted(sorttracks) ]
        return listtracks

    def populate_directory(self, playlistpath, recursive = True):
        # Add all tracks inside the folder and its subfolders recursively.
        # Folders containing no music and only a single Album
        # would generate duplicated playlists. That is intended and "wont fix".
        # Empty folders (inside the music path) will generate an error -> "wont fix".
        if "/iPod_Control/Podcasts/" in playlistpath:
            self.set_podcast()
        listtracks = []
        for (dirpath, dirnames, filenames) in os.walk(playlistpath):
            dirnames.sort()

            # Ignore any hidden directories
            if "/." not in dirpath:
                for filename in sorted(filenames, key = lambda x: x.lower()):
                    # Only add valid music files to playlist
                    if os.path.splitext(filename)[1].lower() in (".mp3", ".m4a", ".m4b", ".m4p", ".aa", ".wav"):
                        fullPath = os.path.abspath(os.path.join(dirpath, filename))
                        listtracks.append(fullPath)
            if not recursive:
                break
        return listtracks

    def remove_relatives(self, relative, filename):
        base = os.path.dirname(os.path.abspath(filename))
        if not os.path.exists(relative):
            relative = os.path.join(base, relative)
        fullPath = relative
        return fullPath

    def populate(self, obj):
        # Create a playlist of the folder and all subfolders
        if type(obj) == type(()):
            self.listtracks = obj[1]
            text = obj[0]
        else:
            filename = obj
            if os.path.isdir(filename):
                self.listtracks = self.populate_directory(filename)
                text = os.path.splitext(os.path.basename(filename))[0]
            else:
                # Read the playlist file
                with open(filename, 'r', errors="replace") as f:
                    data = f.readlines()

                extension = os.path.splitext(filename)[1].lower()
                if extension == '.pls':
                    self.listtracks = self.populate_pls(data)
                elif extension == '.m3u':
                    self.listtracks = self.populate_m3u(data)
                else:
                    raise

                # Ensure all paths are not relative to the playlist file
                for i in range(len(self.listtracks)):
                    self.listtracks[i] = self.remove_relatives(self.listtracks[i], filename)
                text = os.path.splitext(os.path.basename(filename))[0]

        # Handle the VoiceOverData
        self["dbid"] = hashlib.md5(text.encode('utf-8')).digest()[:8]
        self.text_to_speech(text, self["dbid"], True)

    def construct(self, tracks):
        self["total_length"] = 44 + (4 * len(self.listtracks))
        self["number_of_songs"] = 0

        chunks = bytes()
        for i in self.listtracks:
            path = self.ipod_to_path(i)
            position = -1
            if self["listtype"] == 1 and "/iPod_Control/Podcasts/" in path:
                print ('not including podcast in master playlist: {}'.format(path))
                continue
            try:
                position = tracks.index(path)
            except:
                # Print an error if no track was found.
                # Empty playlists are handeled in the PlaylistHeader class.
                print("Error: Could not find track \"" + path + "\".")
                print("Maybe its an invalid FAT filesystem name. Please fix your playlist. Skipping track.")
            if position > -1:
                chunks += struct.pack("I", position)
                self["number_of_songs"] += 1
        self["number_of_nonaudio"] = self["number_of_songs"]

        output = Record.construct(self)
        return output + chunks

class Shuffler(object):
    def __init__(self, path, track_voiceover=False, playlist_voiceover=False, rename=False, trackgain=0, auto_dir_playlists=None, auto_id3_playlists=None):
        self.path = os.path.abspath(path)
        self.tracks = []
        self.albums = []
        self.artists = []
        self.lists = []
        self.tunessd = None
        self.track_voiceover = track_voiceover
        self.playlist_voiceover = playlist_voiceover
        self.rename = rename
        self.trackgain = trackgain
        self.auto_dir_playlists = auto_dir_playlists
        self.auto_id3_playlists = auto_id3_playlists

    def initialize(self):
      # remove existing voiceover files (they are either useless or will be overwritten anyway)
      for dirname in ('iPod_Control/Speakable/Playlists', 'iPod_Control/Speakable/Tracks'):
          shutil.rmtree(os.path.join(self.path, dirname), ignore_errors=True)
      for dirname in ('iPod_Control/iTunes', 'iPod_Control/Music', 'iPod_Control/Podcasts', 'iPod_Control/Speakable/Playlists', 'iPod_Control/Speakable/Tracks'):
          make_dir_if_absent(os.path.join(self.path, dirname))

    def dump_state(self):
        print("Shuffle DB state")
        print("Tracks", self.tracks)
        print("Albums", self.albums)
        print("Artists", self.artists)
        print("Playlists", self.lists)

    def populate(self):
        self.tunessd = TunesSD(self)
        for (dirpath, dirnames, filenames) in os.walk(self.path):
            dirnames.sort()
            relpath = get_relpath(dirpath, self.path)
            # Ignore the speakable directory and any hidden directories
            if not is_path_prefix("iPod_Control/Speakable", relpath) and "/." not in dirpath:
                for filename in sorted(filenames, key = lambda x: x.lower()):
                    # Ignore hidden files
                    if not filename.startswith("."):
                        fullPath = os.path.abspath(os.path.join(dirpath, filename))
                        if os.path.splitext(filename)[1].lower() in (".mp3", ".m4a", ".m4b", ".m4p", ".aa", ".wav"):
                            self.tracks.append(fullPath)
                        if os.path.splitext(filename)[1].lower() in (".pls", ".m3u"):
                            self.lists.append(fullPath)

            # Create automatic playlists in music directory.
            # Ignore the (music) root and any hidden directories.
            if self.auto_dir_playlists and ("iPod_Control/Music/" in dirpath or "iPod_Control/Podcasts/" in dirpath) and "/." not in dirpath:
                # Only go to a specific depth. -1 is unlimted, 0 is ignored as there is already a master playlist.
                depth = dirpath[len(self.path) + len(os.path.sep):].count(os.path.sep) - 1
                if self.auto_dir_playlists < 0 or depth <= self.auto_dir_playlists:
                    self.lists.append(os.path.abspath(dirpath))

        if self.auto_id3_playlists != None:
            if mutagen:
                for grouped_list in group_tracks_by_id3_template(self.tracks, self.auto_id3_playlists):
                    self.lists.append(grouped_list)
            else:
                print("Error: No mutagen found. Cannot generate auto-id3-playlists.")
                sys.exit(1)

    def write_database(self):
        print("Writing database. This may take a while...")
        with open(os.path.join(self.path, "iPod_Control", "iTunes", "iTunesSD"), "wb") as f:
            try:
                f.write(self.tunessd.construct())
            except IOError as e:
                print("I/O error({0}): {1}".format(e.errno, e.strerror))
                print("Error: Writing iPod database failed.")
                sys.exit(1)

        print("Database written successfully:")
        print("Tracks", len(self.tracks))
        print("Albums", len(self.albums))
        print("Artists", len(self.artists))
        print("Playlists", len(self.lists))

#
# Read all files from the directory
# Construct the appropriate iTunesDB file
# Construct the appropriate iTunesSD file
#   http://shuffle3db.wikispaces.com/iTunesSD3gen
# Use SVOX pico2wave and RHVoice to produce voiceover data
#

def check_unicode(path):
    ret_flag = False # True if there is a recognizable file within this level
    for item in os.listdir(path):
        if os.path.isfile(os.path.join(path, item)):
            if os.path.splitext(item)[1].lower() in audio_ext+list_ext:
                ret_flag = True
                if raises_unicode_error(item):
                    src = os.path.join(path, item)
                    dest = os.path.join(path, hash_error_unicode(item)) + os.path.splitext(item)[1].lower()
                    print('Renaming %s -> %s' % (src, dest))
                    os.rename(src, dest)
        else:
            ret_flag = (check_unicode(os.path.join(path, item)) or ret_flag)
            if ret_flag and raises_unicode_error(item):
                src = os.path.join(path, item)
                new_name = hash_error_unicode(item)
                dest = os.path.join(path, new_name)
                print('Renaming %s -> %s' % (src, dest))
                os.rename(src, dest)
    return ret_flag

def nonnegative_int(string):
    try:
        intval = int(string)
    except ValueError:
        raise argparse.ArgumentTypeError("'%s' must be an integer" % string)

    if intval < 0 or intval > 99:
        raise argparse.ArgumentTypeError("Track gain value should be in range 0-99")
    return intval

def checkPathValidity(path):
    if not os.path.isdir(result.path):
        print("Error finding IPod directory. Maybe it is not connected or mounted?")
        sys.exit(1)

    if not os.access(result.path, os.W_OK):
        print('Unable to get write permissions in the IPod directory')
        sys.exit(1)

def handle_interrupt(signal, frame):
    print("Interrupt detected, exiting...")
    sys.exit(1)

if __name__ == '__main__':
    signal.signal(signal.SIGINT, handle_interrupt)

    parser = argparse.ArgumentParser(description=
    'Python script for building the Track and Playlist database '
    'for the newer gen IPod Shuffle. Version 1.5')

    parser.add_argument('-t', '--track-voiceover', action='store_true',
    help='Enable track voiceover feature')

    parser.add_argument('-p', '--playlist-voiceover', action='store_true',
    help='Enable playlist voiceover feature')

    parser.add_argument('-u', '--rename-unicode', action='store_true',
    help='Rename files causing unicode errors, will do minimal required renaming')

    parser.add_argument('-g', '--track-gain', type=nonnegative_int, default='0',
    help='Specify volume gain (0-99) for all tracks; '
    '0 (default) means no gain and is usually fine; '
    'e.g. 60 is very loud even on minimal player volume')

    parser.add_argument('-d', '--auto-dir-playlists', type=int, default=None, const=-1, nargs='?',
    help='Generate automatic playlists for each folder recursively inside '
    '"IPod_Control/Music/". You can optionally limit the depth: '
    '0=root, 1=artist, 2=album, n=subfoldername, default=-1 (No Limit).')

    parser.add_argument('-i', '--auto-id3-playlists', type=str, default=None, metavar='ID3_TEMPLATE', const='{artist}', nargs='?',
    help='Generate automatic playlists based on the id3 tags of any music '
    'added to the iPod. You can optionally specify a template string '
    'based on which id3 tags are used to generate playlists. For eg. '
    '\'{artist} - {album}\' will use the pair of artist and album to group '
    'tracks under one playlist. Similarly \'{genre}\' will group tracks based '
    'on their genre tag. Default template used is \'{artist}\'')

    parser.add_argument('-v', '--verbose', action='store_true',
    help='Show verbose output of database generation.')

    parser.add_argument('path', help='Path to the IPod\'s root directory')

    result = parser.parse_args()

    # Enable verbose printing if desired
    verboseprint = print if result.verbose else lambda *a, **k: None

    checkPathValidity(result.path)

    if result.rename_unicode:
        check_unicode(result.path)

    if not mutagen:
        print("Warning: No mutagen found. Database will not contain any album nor artist information.")

    verboseprint("Playlist voiceover requested:", result.playlist_voiceover)
    verboseprint("Track voiceover requested:", result.track_voiceover)
    if (result.track_voiceover or result.playlist_voiceover):
        if not Text2Speech.check_support():
            print("Error: Did not find any voiceover program. Voiceover disabled.")
            result.track_voiceover = False
            result.playlist_voiceover = False
        else:
            verboseprint("Voiceover available.")

    shuffle = Shuffler(result.path,
                       track_voiceover=result.track_voiceover,
                       playlist_voiceover=result.playlist_voiceover,
                       rename=result.rename_unicode,
                       trackgain=result.track_gain,
                       auto_dir_playlists=result.auto_dir_playlists,
                       auto_id3_playlists=result.auto_id3_playlists)
    shuffle.initialize()
    shuffle.populate()
    shuffle.write_database()