# Copyright (c) 2016, 2018 Claudiu Popa <pcmanticore@gmail.com>
# Copyright (c) 2018 Ioana Tagirta <ioana.tagirta@gmail.com>

# Licensed under the LGPL: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html
# For details: https://github.com/PyCQA/astroid/blob/master/COPYING.LESSER
import sys

import six

import astroid

PY36 = sys.version_info >= (3, 6)


def _hashlib_transform():
    signature = "value=''"
    template = """
    class %(name)s(object):
      def __init__(self, %(signature)s): pass
      def digest(self):
        return %(digest)s
      def copy(self):
        return self
      def update(self, value): pass
      def hexdigest(self):
        return ''
      @property
      def name(self):
        return %(name)r
      @property
      def block_size(self):
        return 1
      @property
      def digest_size(self):
        return 1
    """
    algorithms_with_signature = dict.fromkeys(
        ["md5", "sha1", "sha224", "sha256", "sha384", "sha512"], signature
    )
    if PY36:
        blake2b_signature = "data=b'', *, digest_size=64, key=b'', salt=b'', \
                person=b'', fanout=1, depth=1, leaf_size=0, node_offset=0, \
                node_depth=0, inner_size=0, last_node=False"
        blake2s_signature = "data=b'', *, digest_size=32, key=b'', salt=b'', \
                person=b'', fanout=1, depth=1, leaf_size=0, node_offset=0, \
                node_depth=0, inner_size=0, last_node=False"
        new_algorithms = dict.fromkeys(
            ["sha3_224", "sha3_256", "sha3_384", "sha3_512", "shake_128", "shake_256"],
            signature,
        )
        algorithms_with_signature.update(new_algorithms)
        algorithms_with_signature.update(
            {"blake2b": blake2b_signature, "blake2s": blake2s_signature}
        )
    classes = "".join(
        template
        % {
            "name": hashfunc,
            "digest": 'b""' if six.PY3 else '""',
            "signature": signature,
        }
        for hashfunc, signature in algorithms_with_signature.items()
    )
    return astroid.parse(classes)


astroid.register_module_extender(astroid.MANAGER, "hashlib", _hashlib_transform)