anime renumber

#!/usr/bin/env python

from optparse import OptionParser
import os
import re
import sys

VERSION = "0.1"
#compatible with Python v2.6.6+

def set_options():
    """
    parses command line options, checks source and destination directory existence.
    """
    global OPT, ARG, DEST
    usage = "%prog [option] dir1 [dir2] [dir3] [...]"
    version = "%prog " + VERSION
    description = "Creates season-based symlinks based for absolutely numbered animes."
    parser = OptionParser(usage=usage,version=version,description=description)
    parser.set_defaults(recursion=False,run=True,verbose=0)

    parser.add_option("-v", "--verbose",
        dest="verbose", action="store_const", const=2,
        help="increases output verbosity")

    parser.add_option("-n", "--dry-run",
        dest="run", action="store_false",
        help="simulate actions without making any changes.")

    (OPT, ARG) = parser.parse_args()

    #checks arguments
    if len(ARG) < 1:
        print "Not enough arguments"
        parser.print_help()
        sys.exit(2)

    for dir in ARG:
        if not os.path.exists(dir):
            print "ERROR:", dir, "does not exist."
            sys.exit(2)

    if OPT.verbose > 2:
        print "OPT =", OPT
        print "ARG =", ARG
        print


def abs2sep(series, aep):
    #if OPT.verbose > 1:
        #print "series =",series
        #print "abs ep =",aep

    anime = {
        'Bleach': [20, 21, 22, 28, 18, 22, 20, 16, 22, 16, 7, 17, 36, 51, 26, 999],
        'Naruto Shippuuden': [32, 21, 18, 17, 24, 31, 8, 24, 21, 22, 24, 999]
        }

    if not(series in anime):
        return (-1,-1)

    a = aep
    s = 0
    e = 0

    for num in anime[series]:
        if a <= 0:
            break
        if (a-num) <= 0:
            e = a
        a -= num
        s += 1

    return (s,e)

def create_symlink(source, target_dir, target_ext, series, season, ep):
    link_name = "%s %dx%d.%s" % (series, season, ep, target_ext)
    target_file = os.path.join(target_dir,link_name)

    # remove existing symlink conflicts in case paths change
    if (OPT.run == True):
        # only remove symlink if they point to different files
        if os.path.islink(target_file):
            if os.stat(source).st_ino != os.stat(target_file).st_ino:
                os.remove(target_file)
            else:
                return

        print source,
        print " ==> ",target_file
        os.symlink(source,target_file)

def main():
    set_options()

    for dir in ARG:
        for dir_path, dir_names, file_names in os.walk(dir):
            for file in file_names:
                match = re.search(r'\[.+\](.+)-\s+(\d+).*\.([^\.]+)$',str(file))

                if match == None:
                    if OPT.verbose > 1:
                        print "[SKIP]", file

                    continue

                series = match.group(1).strip()
                abs_ep = int(match.group(2))
                file_ext = match.group(3).strip()

                sep = abs2sep(series,abs_ep)
                if sep[0] != -1:
                    create_symlink(os.path.join(dir_path,file), dir_path, file_ext, series, sep[0], sep[1])

main()