#!/usr/bin/env python3
import sys
from os import rename
from argparse import ArgumentParser

from normalisename import Normalisename


if __name__ == '__main__':
    # parse arguments
    parser = ArgumentParser(description='Eliminate funky stuff from filenames.')
    parser.add_argument(
        '--separator', '-s', type=str, nargs='?', default='_',
        help='Set separator to use (to replace spaces with).'
    )
    parser.add_argument(
        '--allow', '-a', type=str, nargs='?', action='append',
        help='Specify a special character to allow (it will not be removed).'
    )
    parser.add_argument(
        '--disallow', '-d', type=str, nargs='?', action='append',
        help='Specify a special character to disallow (it will removed).'
    )
    parser.add_argument(
        '--whitelist', '-w', type=str,
        help='Overwrite default whitelist (format: whitespace separated string).'
    )

    mgroup = parser.add_mutually_exclusive_group()
    mgroup.add_argument(
        '--dryrun', '-n', action='store_true',
        help='Do not touch anything, just tell me what would change!'
    )
    mgroup.add_argument(
        '--funky', '-f', action='store_true',
        help='List filenames with special characters'
    )
    mgroup.add_argument(
        '--check', '-c', action='store_true',
        help='Check whether a name is normalised or not'
    )

    parser.add_argument(
        'files', type=str, nargs='+',
        help='File(s) to normalise the name of (relative or absolute path).'
    )

    args = parser.parse_args()

    # verify arguments
    if args.disallow:
        if args.separator in args.disallow:
            sys.exit('Disallowing your chosen separator makes no sense!')

    # declare special characters that will not be removed
    whitelist = {'.', '-'}
    if args.whitelist:
        whitelist = set(args.whitelist.split())

    # modify whitelist based on arguments
    if args.allow:
        whitelist = whitelist.union(set(args.allow))
    if args.disallow:
        whitelist = whitelist.difference(set(args.disallow))

    # define operations
    def listchanges(before, after):
        print(
            f'⤺ {before}\n'
            f'⤻ {after}\n'
        )

    def listfunky(before, _):
        print(before)

    def checkname(before, after):
        if before != after:
            sys.exit(1)
        sys.exit(0)

    operation = rename
    if args.dryrun:
        operation = listchanges
    elif args.funky:
        operation = listfunky
    elif args.check:
        operation = checkname

    # do what needs to be done
    Normalisename(args.separator, whitelist, operation)(args.files)