import os

def indexer(folder):
    for idx,itm in enumerate(folder):
        print("{}: {}".format(idx, itm))  # print contents plus indices
    inp = int(input("Choice [0-{}]: ".format(len(folder))))  # choose index
    return inp

def songindex(folder):  # index chooser for MP3/M4A files
    files = [os.path.abspath(x) for x in os.listdir(folder) if x.endswith((".m4a", ".mp3"))]  # only music files, return absolute paths
    names = [os.path.basename(x) for x in files]  # get just filenames from absolute paths
    idx = indexer(names)  # get selected index
    return files[idx]

def dirindex(folder):  # index chooser for directories
    folders = [os.path.abspath(x) for x in os.listdir(folder) if os.path.isdir(x)]  # only folders, return absolute paths
    names = [os.path.basename(x) for x in folders]  # get last component of folder name (i.e. artist/album)
    idx = indexer(names)  # get selected index
    return folders[idx]

music_dir = os.path.join(os.path.expanduser("~"), "Music")  # C:\users\<yournamehere>\Music
# Alternatively:
# music_dir = os.path.join(os.path.expanduser("~"), "Music", "iTunes", "iTunes Media", "Music")
os.chdir(music_dir)
print("Please choose an artist")
artist = dirindex(music_dir)
os.chdir(artist)
print("\nPlease choose an album")
album = dirindex(artist)
os.chdir(album)
print("\nPlease choose a song")
song = songindex(album)
print("\nNow playing: {}".format(os.path.basename(song)))
os.startfile(song)