arlo: Add alarm control panel component (#9711)

* arlo: Add alarm control panel component

Allows importing arlo base stations as an alarm control panel
component in HA. Lets the users configure a custom home mode since
arlo does not have a built-in home mode.

* fix lint and houndci comments

* Use async_update to update the state

Move the state updating code from state() to update() since it does
I/O.

* Do not set state in __init__

Make sure that update is called by passing the second parameter to
async_add_devices.

* Order imports and fix dos-strings

homeassistant/components/alarm_control_panel/arlo.py

@@ -0,0 +1,117 @@
+"""
+This component provides HA alarm_control_panel support for Arlo.
+
+For more details about this platform, please refer to the documentation at
+https://home-assistant.io/components/alarm_control_panel.arlo/
+"""
+import asyncio
+import logging
+import voluptuous as vol
+
+from homeassistant.components.arlo import (DATA_ARLO, CONF_ATTRIBUTION)
+from homeassistant.components.alarm_control_panel import (AlarmControlPanel,
+                                                          PLATFORM_SCHEMA)
+from homeassistant.const import (ATTR_ATTRIBUTION, STATE_ALARM_ARMED_AWAY,
+                                 STATE_ALARM_ARMED_HOME, STATE_ALARM_DISARMED)
+from homeassistant.helpers import config_validation as cv
+
+DEPENDENCIES = ['arlo']
+
+_LOGGER = logging.getLogger(__name__)
+
+CONF_HOME_MODE_NAME = 'home_mode_name'
+ICON = 'mdi:security'
+ARMED = "armed"
+DISARMED = "disarmed"
+
+PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
+    vol.Optional(CONF_HOME_MODE_NAME, default=ARMED): cv.string,
+})
+
+
+@asyncio.coroutine
+def async_setup_platform(hass, config, async_add_devices, discovery_info=None):
+    """Set up Arlo Base Stations."""
+    data = hass.data[DATA_ARLO]
+
+    if not data.base_stations:
+        return
+
+    home_mode_name = config.get(CONF_HOME_MODE_NAME)
+    base_stations = []
+    for base_station in data.base_stations:
+        base_stations.append(ArloBaseStation(base_station, home_mode_name))
+    async_add_devices(base_stations, True)
+
+
+class ArloBaseStation(AlarmControlPanel):
+    """An AlarmControlPanel implementation for Arlo."""
+
+    def __init__(self, data, home_mode_name):
+        """Initialize the alarm control panel."""
+        self._base_station = data
+        self._home_mode_name = home_mode_name
+        self._state = None
+
+    @property
+    def icon(self):
+        """Return icon."""
+        return ICON
+
+    @property
+    def state(self):
+        """Return the state of the device."""
+        return self._state
+
+    @asyncio.coroutine
+    def async_update(self):
+        """Update the state of the device."""
+        # PyArlo sometimes returns None for mode. So retry 3 times before
+        # returning None.
+        num_retries = 3
+        i = 0
+        while i < num_retries:
+            mode = self._base_station.mode
+            if mode:
+                self._state = self._get_state_from_mode(mode)
+                return
+            i += 1
+        self._state = None
+
+    @asyncio.coroutine
+    def async_alarm_disarm(self, code=None):
+        """Send disarm command."""
+        self._base_station.mode = DISARMED
+
+    @asyncio.coroutine
+    def async_alarm_arm_away(self, code=None):
+        """Send arm away command."""
+        self._base_station.mode = ARMED
+
+    @asyncio.coroutine
+    def async_alarm_arm_home(self, code=None):
+        """Send arm home command. Uses custom mode."""
+        self._base_station.mode = self._home_mode_name
+
+    @property
+    def name(self):
+        """Return the name of the base station."""
+        return self._base_station.name
+
+    @property
+    def device_state_attributes(self):
+        """Return the state attributes."""
+        return {
+            ATTR_ATTRIBUTION: CONF_ATTRIBUTION,
+            'device_id': self._base_station.device_id
+        }
+
+    def _get_state_from_mode(self, mode):
+        """Convert Arlo mode to HA state."""
+        if mode == ARMED:
+            return STATE_ALARM_ARMED_AWAY
+        elif mode == DISARMED:
+            return STATE_ALARM_DISARMED
+        elif mode == self._home_mode_name:
+            return STATE_ALARM_ARMED_HOME
+        return None