# Copyright (C) 2017 Jan Jancar
#
# This file is a part of the Mailman PGP plugin.
#
# 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/>.

"""Strict inline PGP message wrapper."""

from pgpy import PGPMessage
from pgpy.types import Armorable
from public import public


@public
class InlineWrapper:
    """Inline PGP wrapper."""

    def __init__(self, msg):
        """
        Wrap the given message.

        :param msg: The message to wrap.
        :type msg: mailman.email.message.Message
        """
        self.msg = msg

    def _is_inline(self):
        return not self.msg.is_multipart()

    def _as_string(self):
        return str(self.msg.get_payload())

    def _has_armor(self, block_type):
        try:
            dearm = Armorable.ascii_unarmor(self._as_string())
            if dearm['magic'] == block_type:
                return True
        except:
            pass
        return False

    def is_signed(self):
        """
        Whether the message is inline signed (cleartext).

        :return: If the message is inline signed.
        :rtype: bool
        """
        # XXX: This doesnt handle non-cleartext signatures (gpg -s -a)
        return self._is_inline() and self._has_armor('SIGNATURE')

    def is_encrypted(self):
        """
        Whether the message is inline encrypted.

        :return: If the message is inline encrypted.
        :rtype: bool
        """
        # XXX: This mistakes non-cleartext signature as encrypted.
        return self._is_inline() and self._has_armor('MESSAGE')

    def verify(self, key):
        """
        Verify the signature of this message with key.

        :param key: The key to verify with.
        :type key: pgpy.PGPKey
        :return: The verified signature.
        :rtype: pgpy.types.SignatureVerification
        """
        message = PGPMessage.from_blob(self._as_string())
        return key.verify(message)

    def sign(self):
        pass

    def decrypt(self, key):
        """
        Decrypt this message with key.

        :param key: The key to decrypt with.
        :type key: pgpy.PGPKey
        :return: The decrypted message.
        :rtype: PGPMessage
        """
        message = PGPMessage.from_blob(self._as_string())
        return key.decrypt(message)

    def encrypt(self):
        pass