import os
import argparse

DEFAULT_K=32
DEFAULT_N_HT=4
DEFAULT_MIN_HASHSIZE=1e6

def build_construct_args():

    parser = argparse.ArgumentParser(description=
                                     'Build & load a counting Bloom filter.')

    env_ksize = os.environ.get('KHMER_KSIZE', DEFAULT_K)
    env_n_hashes = os.environ.get('KHMER_N_HASHES', DEFAULT_N_HT)
    env_hashsize = os.environ.get('KHMER_MIN_HASHSIZE', DEFAULT_MIN_HASHSIZE)

    parser.add_argument('-q', '--quiet', dest='quiet', default=False,
                        action='store_true')
    parser.add_argument('--ksize', '-k', type=int, dest='ksize',
                        default=env_ksize,
                        help='k-mer size to use')
    parser.add_argument('--n_hashes', '-N', type=int, dest='n_hashes',
                        default=env_n_hashes,
                        help='number of hash tables to use')
    parser.add_argument('--hashsize', '-x', type=float, dest='min_hashsize',
                        default=env_hashsize,
                        help='lower bound on hashsize to use')

    return parser

def build_counting_multifile_args():
    parser = argparse.ArgumentParser(description=
                                     'Use a counting Bloom filter.')

    parser.add_argument('input_table')
    parser.add_argument('input_filenames', nargs='+')

    return parser