import os
import logging

from landscape.lib.fs import read_file
from landscape.monitor.plugin import MonitorPlugin


REBOOT_REQUIRED_FILENAME = "/var/run/reboot-required"


class RebootRequired(MonitorPlugin):
"""
Report whether the system requires a reboot.

@param reboot_required_filename: The path to the flag file that indicates
if the system needs to be rebooted.
"""

persist_name = "reboot-required"
scope = "package"
run_interval = 900 # 15 minutes
run_immediately = True

def __init__(self, reboot_required_filename=REBOOT_REQUIRED_FILENAME):
self._flag_filename = reboot_required_filename
self._packages_filename = reboot_required_filename + ".pkgs"

def _get_flag(self):
"""Return a boolean indicating whether the computer needs a reboot."""
return os.path.exists(self._flag_filename)

def _get_packages(self):
"""Return the list of packages that required a reboot, if any."""
if not os.path.exists(self._packages_filename):
return []

lines = read_file(self._packages_filename).splitlines()
packages = set(line.strip().decode("utf-8") for line in lines if line)
return sorted(packages)

def _create_message(self):
"""Return the body of the reboot-required message to be sent."""
message = {}
flag = self._get_flag()
packages = self._get_packages()
for key, value in [("flag", flag), ("packages", packages)]:
if value == self._persist.get(key):
continue
self._persist.set(key, value)
message[key] = value
return message

def send_message(self):
"""Send a reboot-required message if needed.

A message will be sent only if the reboot-required status of the
system has changed.
"""
message = self._create_message()
if message:
message["type"] = "reboot-required-info"
logging.info("Queueing message with updated "
"reboot-required status.")
self.registry.broker.send_message(message, self._session_id,
urgent=True)

def run(self):
"""Send reboot-required messages if the server accepts them."""
return self.registry.broker.call_if_accepted(
"reboot-required-info", self.send_message)