# Copyright (C) 2001-2006 Python Software Foundation
# Author: Barry Warsaw
# Contact: email-sig@python.org

"""Encodings and related functions."""

__all__ = [
 'encode_7or8bit',
 'encode_base64',
 'encode_noop',
 'encode_quopri',
 ]


from base64 import encodebytes as _bencode
from quopri import encodestring as _encodestring



def _qencode(s):
 enc = _encodestring(s, quotetabs=True)
 # Must encode spaces, which quopri.encodestring() doesn't do
 return enc.replace(b' ', b'=20')


def encode_base64(msg):
 """Encode the message's payload in Base64.

 Also, add an appropriate Content-Transfer-Encoding header.
 """
 orig = msg.get_payload(decode=True)
 encdata = str(_bencode(orig), 'ascii')
 msg.set_payload(encdata)
 msg['Content-Transfer-Encoding'] = 'base64'



def encode_quopri(msg):
 """Encode the message's payload in quoted-printable.

 Also, add an appropriate Content-Transfer-Encoding header.
 """
 orig = msg.get_payload(decode=True)
 encdata = _qencode(orig)
 msg.set_payload(encdata)
 msg['Content-Transfer-Encoding'] = 'quoted-printable'



def encode_7or8bit(msg):
 """Set the Content-Transfer-Encoding header to 7bit or 8bit."""
 orig = msg.get_payload(decode=True)
 if orig is None:
 # There's no payload. For backwards compatibility we use 7bit
 msg['Content-Transfer-Encoding'] = '7bit'
 return
 # We play a trick to make this go fast. If decoding from ASCII succeeds,
 # we know the data must be 7bit, otherwise treat it as 8bit.
 try:
 orig.decode('ascii')
 except UnicodeError:
 msg['Content-Transfer-Encoding'] = '8bit'
 else:
 msg['Content-Transfer-Encoding'] = '7bit'



def encode_noop(msg):
 """Do nothing."""