import logging
import os
from configparser import ConfigParser, NoOptionError

from landscape.client import GROUP, USER
from landscape.client.monitor.plugin import DataWatcher
from landscape.lib.fs import read_binary_file
from landscape.lib.persist import Persist

KEYSTONE_CONFIG_FILE = "/etc/keystone/keystone.conf"


class KeystoneToken(DataWatcher):
    """
    A plugin which pulls the admin_token from the keystone configuration file
    and sends it to the landscape server.
    """

    message_type = "keystone-token"
    message_key = "data"
    run_interval = 60 * 15
    scope = "openstack"

    def __init__(self, keystone_config_file=KEYSTONE_CONFIG_FILE):
        self._keystone_config_file = keystone_config_file

    def register(self, client):
        super().register(client)
        self._persist_filename = os.path.join(
            self.registry.config.data_path,
            "keystone.bpickle",
        )
        self._persist = Persist(
            filename=self._persist_filename,
            user=USER,
            group=GROUP,
        )
        self.registry.reactor.call_every(
            self.registry.config.flush_interval,
            self.flush,
        )

    def _reset(self):
        """
        Reset the persist.
        """
        self._persist.remove("data")

    def flush(self):
        self._persist.save(self._persist_filename)

    def get_data(self):
        """
        Return the Keystone administrative token.
        """
        if not os.path.exists(self._keystone_config_file):
            return None

        config = ConfigParser()
        # We need to use the surrogateescape error handler as the
        # admin_token my contain arbitrary bytes.
        config_str = read_binary_file(self._keystone_config_file).decode(
            "utf-8",
            "surrogateescape",
        )
        config.read_string(config_str)
        try:
            admin_token = config.get("DEFAULT", "admin_token")
        except NoOptionError:
            logging.error(
                f"KeystoneToken: No admin_token found in {self._keystone_config_file}",
            )
            return None

        admin_token = admin_token.encode("utf-8", "surrogateescape")

        return admin_token
