# Source code for M2Crypto.Engine

    # vim: sts=4 sw=4 et
    from __future__ import absolute_import

    """
    M2Crypto wrapper for OpenSSL ENGINE API.

    Pavel Shramov
    IMEC MSU
    """

    from M2Crypto import EVP, Err, X509, m2, six
    from typing import AnyStr, Callable, Optional  # noqa

    class EngineError(Exception):
        pass

    m2.engine_init_error(EngineError)

    class Engine(object):
        """Wrapper for ENGINE object."""

        m2_engine_free = m2.engine_free

        def __init__(self, id=None, _ptr=None, _pyfree=1):
            # type: (Optional[bytes], Optional[bytes], int) -> None
            """Create new Engine from ENGINE pointer or obtain by id"""
            if not _ptr and not id:
                raise ValueError("No engine id specified")
            self._ptr = _ptr
            if not self._ptr:
                self._ptr = m2.engine_by_id(id)
                if not self._ptr:
                    raise ValueError("Unknown engine: %s" % id)
            self._pyfree = _pyfree

        def __del__(self):
            # type: () -> None
            if getattr(self, '_pyfree', 0):
                self.m2_engine_free(self._ptr)

        def init(self):
            # type: () -> int
            """Obtain a functional reference to the engine.

            :return: 0 on error, non-zero on success."""
            return m2.engine_init(self._ptr)

        def finish(self):
            # type: () -> int
            """Release a functional and structural reference to the engine."""
            return m2.engine_finish(self._ptr)

        def ctrl_cmd_string(self, cmd, arg, optional=0):
            # type: (AnyStr, Optional[AnyStr], int) -> None
            """Call ENGINE_ctrl_cmd_string"""
            cmd = six.ensure_str(cmd)
            if arg is not None:
                arg = six.ensure_str(arg)
            if not m2.engine_ctrl_cmd_string(self._ptr, cmd, arg, optional):
                raise EngineError(Err.get_error())

        def get_name(self):
            # type: () -> bytes
            """Return engine name"""
            return m2.engine_get_name(self._ptr)

        def get_id(self):
            # type: () -> bytes
            """Return engine id"""
            return m2.engine_get_id(self._ptr)

        def set_default(self, methods=m2.ENGINE_METHOD_ALL):
            # type: (int) -> int
            """
            Use this engine as default for methods specified in argument

            :param methods: Possible values are bitwise OR of m2.ENGINE_METHOD_*
            """
            return m2.engine_set_default(self._ptr, methods)

        def _engine_load_key(self, func, name, pin=None):
            # type: (Callable, bytes, Optional[bytes]) -> EVP.PKey
            """Helper function for loading keys"""
            ui = m2.ui_openssl()
            cbd = m2.engine_pkcs11_data_new(pin)
            try:
                kptr = func(self._ptr, name, ui, cbd)
                if not kptr:
                    raise EngineError(Err.get_error())
                key = EVP.PKey(kptr, _pyfree=1)
            finally:
                m2.engine_pkcs11_data_free(cbd)
            return key

        def load_private_key(self, name, pin=None):
            # type: (bytes, Optional[bytes]) -> X509.X509
            """Load private key with engine methods (e.g from smartcard).
                If pin is not set it will be asked
            """
            return self._engine_load_key(m2.engine_load_private_key, name, pin)

        def load_public_key(self, name, pin=None):
            # type: (bytes, Optional[bytes]) -> EVP.PKey
            """Load public key with engine methods (e.g from smartcard)."""
            return self._engine_load_key(m2.engine_load_public_key, name, pin)

        def load_certificate(self, name):
            # type: (bytes) -> X509.X509
            """Load certificate from engine (e.g from smartcard).
            NOTE: This function may be not implemented by engine!"""
            cptr = m2.engine_load_certificate(self._ptr, name)
            if not cptr:
                raise EngineError("Certificate or card not found")
            return X509.X509(cptr, _pyfree=1)

    def load_dynamic_engine(id, sopath):
        # type: (bytes, AnyStr) -> Engine
        """Load and return dymanic engine from sopath and assign id to it"""
        if isinstance(sopath, six.text_type):
            sopath = sopath.encode('utf8')
        m2.engine_load_dynamic()
        e = Engine('dynamic')
        e.ctrl_cmd_string('SO_PATH', sopath)
        e.ctrl_cmd_string('ID', id)
        e.ctrl_cmd_string('LIST_ADD', '1')
        e.ctrl_cmd_string('LOAD', None)
        return e

    def load_dynamic():
        # type: () -> None
        """Load dynamic engine"""
        m2.engine_load_dynamic()

    def load_openssl():
        # type: () -> None
        """Load openssl engine"""
        m2.engine_load_openssl()

    def cleanup():
        # type: () -> None
        """If you load any engines, you need to clean up after your application
        is finished with the engines."""
        m2.engine_cleanup()