# Copyright (C) 2015-2019 Virgil Security, Inc.
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# Lead Maintainer: Virgil Security Inc. <support@virgilsecurity.com>


from ctypes import *
from ._c_bridge import VscfKeyAsn1Serializer
from virgil_crypto_lib.common._c_bridge import Buffer
from ._c_bridge import VscfStatus
from ._c_bridge._vscf_error import vscf_error_t
from .key_serializer import KeySerializer


class KeyAsn1Serializer(KeySerializer):
    """Implements key serialization in the ASN.1 format (DER / PEM):
        - SEC1 - for EC private keys;
        - PKCS#8 - for other keys."""

    def __init__(self):
        """Create underlying C context."""
        self._lib_vscf_key_asn1_serializer = VscfKeyAsn1Serializer()
        self._c_impl = None
        self._ctx = None
        self.ctx = self._lib_vscf_key_asn1_serializer.vscf_key_asn1_serializer_new()

    def __delete__(self, instance):
        """Destroy underlying C context."""
        self._lib_vscf_key_asn1_serializer.vscf_key_asn1_serializer_delete(self.ctx)

    def set_asn1_writer(self, asn1_writer):
        self._lib_vscf_key_asn1_serializer.vscf_key_asn1_serializer_use_asn1_writer(self.ctx, asn1_writer.c_impl)

    def serialized_public_key_len(self, public_key):
        """Calculate buffer size enough to hold serialized public key.

        Precondition: public key must be exportable."""
        result = self._lib_vscf_key_asn1_serializer.vscf_key_asn1_serializer_serialized_public_key_len(self.ctx, public_key.ctx)
        return result

    def serialize_public_key(self, public_key):
        """Serialize given public key to an interchangeable format.

        Precondition: public key must be exportable."""
        out = Buffer(self.serialized_public_key_len(public_key=public_key))
        status = self._lib_vscf_key_asn1_serializer.vscf_key_asn1_serializer_serialize_public_key(self.ctx, public_key.ctx, out.c_buffer)
        VscfStatus.handle_status(status)
        return out.get_bytes()

    def serialized_private_key_len(self, private_key):
        """Calculate buffer size enough to hold serialized private key.

        Precondition: private key must be exportable."""
        result = self._lib_vscf_key_asn1_serializer.vscf_key_asn1_serializer_serialized_private_key_len(self.ctx, private_key.ctx)
        return result

    def serialize_private_key(self, private_key):
        """Serialize given private key to an interchangeable format.

        Precondition: private key must be exportable."""
        out = Buffer(self.serialized_private_key_len(private_key=private_key))
        status = self._lib_vscf_key_asn1_serializer.vscf_key_asn1_serializer_serialize_private_key(self.ctx, private_key.ctx, out.c_buffer)
        VscfStatus.handle_status(status)
        return out.get_bytes()

    def setup_defaults(self):
        """Setup predefined values to the uninitialized class dependencies."""
        self._lib_vscf_key_asn1_serializer.vscf_key_asn1_serializer_setup_defaults(self.ctx)

    def serialize_public_key_inplace(self, public_key):
        """Serialize Public Key by using internal ASN.1 writer.
        Note, that caller code is responsible to reset ASN.1 writer with
        an output buffer."""
        error = vscf_error_t()
        result = self._lib_vscf_key_asn1_serializer.vscf_key_asn1_serializer_serialize_public_key_inplace(self.ctx, public_key.ctx, error)
        VscfStatus.handle_status(error.status)
        return result

    def serialize_private_key_inplace(self, private_key):
        """Serialize Private Key by using internal ASN.1 writer.
        Note, that caller code is responsible to reset ASN.1 writer with
        an output buffer."""
        error = vscf_error_t()
        result = self._lib_vscf_key_asn1_serializer.vscf_key_asn1_serializer_serialize_private_key_inplace(self.ctx, private_key.ctx, error)
        VscfStatus.handle_status(error.status)
        return result

    @classmethod
    def take_c_ctx(cls, c_ctx):
        inst = cls.__new__(cls)
        inst._lib_vscf_key_asn1_serializer = VscfKeyAsn1Serializer()
        inst.ctx = c_ctx
        return inst

    @classmethod
    def use_c_ctx(cls, c_ctx):
        inst = cls.__new__(cls)
        inst._lib_vscf_key_asn1_serializer = VscfKeyAsn1Serializer()
        inst.ctx = inst._lib_vscf_key_asn1_serializer.vscf_key_asn1_serializer_shallow_copy(c_ctx)
        return inst

    @property
    def c_impl(self):
        return self._c_impl

    @property
    def ctx(self):
        return self._ctx

    @ctx.setter
    def ctx(self, value):
        self._ctx = self._lib_vscf_key_asn1_serializer.vscf_key_asn1_serializer_shallow_copy(value)
        self._c_impl = self._lib_vscf_key_asn1_serializer.vscf_key_asn1_serializer_impl(self.ctx)
