"""Independent AppDaemon worker monitoring the boiler climate heartbeat."""
import time

import appdaemon.plugins.hass.hassapi as hass
from logger_interface import LoggerInterface
from boilerregulator import finite


class BoilerWatchdog(hass.Hass, LoggerInterface):
    def initialize(self):
        self.initialize_logger_interface(self.get_ad_api(), ascii_encode=False)
        self.base = self.args.get('mqtt_topic', 'appdaemon/radiator_heating').rstrip('/')
        self.mqtt_namespace = self.args.get('mqtt_namespace', 'mqtt')
        self.timeout = finite(self.args.get('heartbeat_timeout', 180))
        if self.timeout < 60:
            raise ValueError('heartbeat_timeout must be at least 60 seconds')
        if self.AD.plugins.get_plugin_object(self.mqtt_namespace) is None:
            raise RuntimeError('MQTT plugin missing; configure it and restart AppDaemon')
        self.last_heartbeat = None
        self.waiting_since = time.monotonic()
        self.fault = False
        self.warned = False
        self.listen_event(self._mqtt_event, 'MQTT_MESSAGE', namespace=self.mqtt_namespace)
        self.run_every(self._check, 'now', 10)
        self._check()

    def _mqtt_event(self, event, data, kwargs):
        if data.get('topic') == self.base + '/heartbeat':
            self.last_heartbeat = time.monotonic()
            if self.warned:
                self.log_info('Boiler climate heartbeat recovered')
            self.fault = False
            self.warned = False
        elif data.get('topic') is None and data.get('state') == 'Connected':
            self.last_heartbeat = None
            self.waiting_since = time.monotonic()
            self.fault = False
            self.warned = False
            self._check()

    def _check(self, kwargs=None):
        age = time.monotonic() - (self.waiting_since if self.last_heartbeat is None else self.last_heartbeat)
        if self.last_heartbeat is None or age >= self.timeout:
            if not self.fault:
                self.call_service('mqtt/publish', namespace=self.mqtt_namespace,
                                  topic=self.base + '/availability', payload='offline', qos=0, retain=True)
                self.fault = True
            if age >= self.timeout and not self.warned:
                self.log_warning('Boiler climate unavailable: no heartbeat within the timeout')
                self.warned = True