# Copyright 2016  Lars Wirzenius
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# =*= License: GPL-3+ =*=


import pgpwordlist

_words = pgpwordlist.pgp_word_list


def get_word(hex, offset):
    hex = hex.lower()
    t = _words.get(hex)
    if t is None:
        raise KeyError(hex)
    return t[offset % 2]


def get_hex(word):
    for hex, t in _words.items():
        if word.lower() in t:
            return hex.lower()


def hex_to_words(hexstr):
    words = [get_word(hex, i) for i, hex in enumerate(_hex_bytes(hexstr))]
    return ' '.join(words)


def _hex_bytes(hexstr):
    for i in range(0, len(hexstr), 2):
        yield hexstr[i:i+2]


def words_to_hex(wordstr):
    return ''.join(get_hex(w) for w in wordstr.split())