# 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 VscfSaltedKdfAlgInfo
from virgil_crypto_lib.common._c_bridge import Data
from ._c_bridge import VscfImplTag
from .alg_info import AlgInfo


class SaltedKdfAlgInfo(AlgInfo):
    """Handle KDF algorithms that are configured with salt and iteration count."""

    def __init__(self):
        """Create underlying C context."""
        self._lib_vscf_salted_kdf_alg_info = VscfSaltedKdfAlgInfo()
        self._c_impl = None
        self._ctx = None
        self.ctx = self._lib_vscf_salted_kdf_alg_info.vscf_salted_kdf_alg_info_new()

    def __delete__(self, instance):
        """Destroy underlying C context."""
        self._lib_vscf_salted_kdf_alg_info.vscf_salted_kdf_alg_info_delete(self.ctx)

    @classmethod
    def with_members(cls, alg_id, hash_alg_info, salt, iteration_count):
        """Create algorithm info with identificator, HASH algorithm info,
        salt and iteration count."""
        d_salt = Data(salt)
        inst = cls.__new__(cls)
        inst._lib_vscf_salted_kdf_alg_info = VscfSaltedKdfAlgInfo()
        inst.ctx = inst._lib_vscf_salted_kdf_alg_info.vscf_salted_kdf_alg_info_new_with_members(alg_id, hash_alg_info.c_impl, d_salt.data, iteration_count)
        return inst

    def alg_id(self):
        """Provide algorithm identificator."""
        result = self._lib_vscf_salted_kdf_alg_info.vscf_salted_kdf_alg_info_alg_id(self.ctx)
        return result

    def hash_alg_info(self):
        """Return hash algorithm information."""
        result = self._lib_vscf_salted_kdf_alg_info.vscf_salted_kdf_alg_info_hash_alg_info(self.ctx)
        instance = VscfImplTag.get_type(result)[0].use_c_ctx(cast(result, POINTER(VscfImplTag.get_type(result)[1])))
        return instance

    def salt(self):
        """Return KDF salt."""
        result = self._lib_vscf_salted_kdf_alg_info.vscf_salted_kdf_alg_info_salt(self.ctx)
        instance = Data.take_c_ctx(result)
        cleaned_bytes = bytearray(instance)
        return cleaned_bytes

    def iteration_count(self):
        """Return KDF iteration count.
        Note, can be 0 if KDF does not need the iteration count."""
        result = self._lib_vscf_salted_kdf_alg_info.vscf_salted_kdf_alg_info_iteration_count(self.ctx)
        return result

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

    @classmethod
    def use_c_ctx(cls, c_ctx):
        inst = cls.__new__(cls)
        inst._lib_vscf_salted_kdf_alg_info = VscfSaltedKdfAlgInfo()
        inst.ctx = inst._lib_vscf_salted_kdf_alg_info.vscf_salted_kdf_alg_info_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_salted_kdf_alg_info.vscf_salted_kdf_alg_info_shallow_copy(value)
        self._c_impl = self._lib_vscf_salted_kdf_alg_info.vscf_salted_kdf_alg_info_impl(self.ctx)
