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"""Native Password Authentication Plugin."""

import logging
import struct

from hashlib import sha1

from .. import errors
from . import BaseAuthPlugin

logging.getLogger(__name__).addHandler(logging.NullHandler())

_LOGGER = logging.getLogger(__name__)

AUTHENTICATION_PLUGIN_CLASS = "MySQLNativePasswordAuthPlugin"


class MySQLNativePasswordAuthPlugin(BaseAuthPlugin):
    """Class implementing the MySQL Native Password authentication plugin"""

    requires_ssl = False
    plugin_name = "mysql_native_password"

    def prepare_password(self):
        """Prepares and returns password as native MySQL 4.1+ password"""
        if not self._auth_data:
            raise errors.InterfaceError("Missing authentication data (seed)")

        if not self._password:
            return b""
        password = self._password

        if isinstance(self._password, str):
            password = self._password.encode("utf-8")
        else:
            password = self._password

        auth_data = self._auth_data

        hash4 = None
        try:
            hash1 = sha1(password).digest()
            hash2 = sha1(hash1).digest()
            hash3 = sha1(auth_data + hash2).digest()
            xored = [h1 ^ h3 for (h1, h3) in zip(hash1, hash3)]
            hash4 = struct.pack("20B", *xored)
        except (struct.error, TypeError) as err:
            raise errors.InterfaceError(f"Failed scrambling password; {err}") from err

        return hash4
