# -*- coding: utf-8 -*-
#
# Copyright (c) 2020-2021, Felix Fontein <felix@fontein.de>
# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
# SPDX-License-Identifier: GPL-3.0-or-later

from __future__ import absolute_import, division, print_function


__metaclass__ = type


import abc
import traceback

from ansible.module_utils import six
from ansible.module_utils.basic import missing_required_lib
from ansible.module_utils.common.text.converters import to_native
from ansible_collections.community.crypto.plugins.module_utils.crypto.basic import (
    CRYPTOGRAPHY_HAS_ED448,
    CRYPTOGRAPHY_HAS_ED25519,
    CRYPTOGRAPHY_HAS_X448,
    CRYPTOGRAPHY_HAS_X25519,
    OpenSSLObjectError,
)
from ansible_collections.community.crypto.plugins.module_utils.crypto.support import (
    get_fingerprint_of_bytes,
    load_publickey,
)
from ansible_collections.community.crypto.plugins.module_utils.version import (
    LooseVersion,
)


MINIMAL_CRYPTOGRAPHY_VERSION = "1.2.3"

CRYPTOGRAPHY_IMP_ERR = None
try:
    import cryptography
    from cryptography.hazmat.primitives import serialization

    CRYPTOGRAPHY_VERSION = LooseVersion(cryptography.__version__)
except ImportError:
    CRYPTOGRAPHY_IMP_ERR = traceback.format_exc()
    CRYPTOGRAPHY_FOUND = False
else:
    CRYPTOGRAPHY_FOUND = True


def _get_cryptography_public_key_info(key):
    key_public_data = dict()
    if isinstance(key, cryptography.hazmat.primitives.asymmetric.rsa.RSAPublicKey):
        key_type = "RSA"
        public_numbers = key.public_numbers()
        key_public_data["size"] = key.key_size
        key_public_data["modulus"] = public_numbers.n
        key_public_data["exponent"] = public_numbers.e
    elif isinstance(key, cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKey):
        key_type = "DSA"
        parameter_numbers = key.parameters().parameter_numbers()
        public_numbers = key.public_numbers()
        key_public_data["size"] = key.key_size
        key_public_data["p"] = parameter_numbers.p
        key_public_data["q"] = parameter_numbers.q
        key_public_data["g"] = parameter_numbers.g
        key_public_data["y"] = public_numbers.y
    elif CRYPTOGRAPHY_HAS_X25519 and isinstance(
        key, cryptography.hazmat.primitives.asymmetric.x25519.X25519PublicKey
    ):
        key_type = "X25519"
    elif CRYPTOGRAPHY_HAS_X448 and isinstance(
        key, cryptography.hazmat.primitives.asymmetric.x448.X448PublicKey
    ):
        key_type = "X448"
    elif CRYPTOGRAPHY_HAS_ED25519 and isinstance(
        key, cryptography.hazmat.primitives.asymmetric.ed25519.Ed25519PublicKey
    ):
        key_type = "Ed25519"
    elif CRYPTOGRAPHY_HAS_ED448 and isinstance(
        key, cryptography.hazmat.primitives.asymmetric.ed448.Ed448PublicKey
    ):
        key_type = "Ed448"
    elif isinstance(
        key, cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey
    ):
        key_type = "ECC"
        public_numbers = key.public_numbers()
        key_public_data["curve"] = key.curve.name
        key_public_data["x"] = public_numbers.x
        key_public_data["y"] = public_numbers.y
        key_public_data["exponent_size"] = key.curve.key_size
    else:
        key_type = "unknown ({0})".format(type(key))
    return key_type, key_public_data


class PublicKeyParseError(OpenSSLObjectError):
    def __init__(self, msg, result):
        super(PublicKeyParseError, self).__init__(msg)
        self.error_message = msg
        self.result = result


@six.add_metaclass(abc.ABCMeta)
class PublicKeyInfoRetrieval(object):
    def __init__(self, module, backend, content=None, key=None):
        # content must be a bytes string
        self.module = module
        self.backend = backend
        self.content = content
        self.key = key

    @abc.abstractmethod
    def _get_public_key(self, binary):
        pass

    @abc.abstractmethod
    def _get_key_info(self):
        pass

    def get_info(self, prefer_one_fingerprint=False):
        result = dict()
        if self.key is None:
            try:
                self.key = load_publickey(content=self.content, backend=self.backend)
            except OpenSSLObjectError as e:
                raise PublicKeyParseError(to_native(e), {})

        pk = self._get_public_key(binary=True)
        result["fingerprints"] = (
            get_fingerprint_of_bytes(pk, prefer_one=prefer_one_fingerprint)
            if pk is not None
            else dict()
        )

        key_type, key_public_data = self._get_key_info()
        result["type"] = key_type
        result["public_data"] = key_public_data
        return result


class PublicKeyInfoRetrievalCryptography(PublicKeyInfoRetrieval):
    """Validate the supplied public key, using the cryptography backend"""

    def __init__(self, module, content=None, key=None):
        super(PublicKeyInfoRetrievalCryptography, self).__init__(
            module, "cryptography", content=content, key=key
        )

    def _get_public_key(self, binary):
        return self.key.public_bytes(
            serialization.Encoding.DER if binary else serialization.Encoding.PEM,
            serialization.PublicFormat.SubjectPublicKeyInfo,
        )

    def _get_key_info(self):
        return _get_cryptography_public_key_info(self.key)


def get_publickey_info(
    module, backend, content=None, key=None, prefer_one_fingerprint=False
):
    if backend == "cryptography":
        info = PublicKeyInfoRetrievalCryptography(module, content=content, key=key)
    return info.get_info(prefer_one_fingerprint=prefer_one_fingerprint)


def select_backend(module, backend, content=None, key=None):
    if backend == "auto":
        # Detection what is possible
        can_use_cryptography = (
            CRYPTOGRAPHY_FOUND
            and CRYPTOGRAPHY_VERSION >= LooseVersion(MINIMAL_CRYPTOGRAPHY_VERSION)
        )

        # Try cryptography
        if can_use_cryptography:
            backend = "cryptography"

        # Success?
        if backend == "auto":
            module.fail_json(
                msg=(
                    "Cannot detect any of the required Python libraries "
                    "cryptography (>= {0})"
                ).format(MINIMAL_CRYPTOGRAPHY_VERSION)
            )

    if backend == "cryptography":
        if not CRYPTOGRAPHY_FOUND:
            module.fail_json(
                msg=missing_required_lib(
                    "cryptography >= {0}".format(MINIMAL_CRYPTOGRAPHY_VERSION)
                ),
                exception=CRYPTOGRAPHY_IMP_ERR,
            )
        return backend, PublicKeyInfoRetrievalCryptography(
            module, content=content, key=key
        )
    else:
        raise ValueError("Unsupported value for backend: {0}".format(backend))