import torrent_parser as tp
import os
import argparse


def run(torrent_file, saved_location):
    data = tp.parse_torrent_file(torrent_file)
    dir_name = data['info']['name']
    os.chdir(os.path.join(saved_location, dir_name))
    files_torrent = set([os.path.join(*d['path'])
                         for d in data['info']['files']])
    files_actual = set()
    for root, directories, filenames in os.walk('.'):
        for filename in filenames:
            files_actual.add(os.path.join(root, filename)[2:])

    files_missing = set()
    for fname in files_torrent:
        if fname not in files_actual:
            files_missing.add(fname)
    files_useless = set()
    for fname in files_actual:
        if fname not in files_torrent:
            files_useless.add(fname)

    return files_useless, files_missing


def main():
    parser = argparse.ArgumentParser(
        description='remove useless files in the torrent download directory')
    parser.add_argument('-t', type=str, dest='torrent_file',
                        help='path to .torrent file', required=True)
    parser.add_argument('-d', type=str, dest='saved_location',
                        help='path to saved_location', required=True)
    parser.add_argument('-r', dest='remove_useless_files',
                        help='whether delete files', action='store_true')
    args = parser.parse_args()
    torrent_file = args.torrent_file
    saved_location = args.saved_location
    remove_useless_files = args.remove_useless_files
    files_useless, files_missing = run(torrent_file, saved_location)
    files_uselessQ, files_missingQ = len(
        files_useless) > 0, len(files_missing) > 0
    if not files_missingQ and not files_uselessQ:
        print('you have a perfect copy.')
        exit(0)
    if files_uselessQ:
        print('useless:', files_useless)
    if files_missingQ:
        print('missing:', files_missing)
    if remove_useless_files:
        if files_missingQ:
            print(
                'torrent file not complete or directory specification error, aborting for safety')
            exit(-1)
        for i in files_useless:
            os.remove(i)
        print('removed.')


if __name__ == '__main__':
    main()