Add aurora sensor (#6003)

* Add aurora sensor

* allow custom forecast threshold for aurora binary sensor

* move AuroraGateway functionality to Aurora data object to conform with HA standards

homeassistant/components/binary_sensor/aurora.py

@@ -0,0 +1,148 @@
+"""
+Support for aurora forecast data sensor.
+
+For more details about this platform, please refer to the documentation at
+https://home-assistant.io/components/binary_sensor.aurora/
+"""
+from datetime import timedelta
+import logging
+
+import requests
+import voluptuous as vol
+
+from homeassistant.components.binary_sensor \
+    import (BinarySensorDevice, PLATFORM_SCHEMA)
+from homeassistant.const import (CONF_NAME)
+import homeassistant.helpers.config_validation as cv
+from homeassistant.util import Throttle
+
+CONF_THRESHOLD = "forecast_threshold"
+
+_LOGGER = logging.getLogger(__name__)
+
+DEFAULT_NAME = 'Aurora Visibility'
+DEFAULT_DEVICE_CLASS = "visible"
+DEFAULT_THRESHOLD = 75
+
+MIN_TIME_BETWEEN_UPDATES = timedelta(minutes=5)
+
+PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
+    vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
+    vol.Optional(CONF_THRESHOLD, default=DEFAULT_THRESHOLD): cv.positive_int,
+})
+
+
+def setup_platform(hass, config, add_devices, discovery_info=None):
+    """Set up the aurora sensor."""
+    if None in (hass.config.latitude, hass.config.longitude):
+        _LOGGER.error("Lat. or long. not set in Home Assistant config")
+        return False
+
+    name = config.get(CONF_NAME)
+    threshold = config.get(CONF_THRESHOLD)
+
+    try:
+        aurora_data = AuroraData(
+            hass.config.latitude,
+            hass.config.longitude,
+            threshold
+        )
+        aurora_data.update()
+    except requests.exceptions.HTTPError as error:
+        _LOGGER.error(
+            "Connection to aurora forecast service failed: %s", error)
+        return False
+
+    add_devices([AuroraSensor(aurora_data, name)], True)
+
+
+class AuroraSensor(BinarySensorDevice):
+    """Implementation of an aurora sensor."""
+
+    def __init__(self, aurora_data, name):
+        """Initialize the sensor."""
+        self.aurora_data = aurora_data
+        self._name = name
+
+    @property
+    def name(self):
+        """Return the name of the sensor."""
+        return '{}'.format(self._name)
+
+    @property
+    def is_on(self):
+        """Return true if aurora is visible."""
+        return self.aurora_data.is_visible if self.aurora_data else False
+
+    @property
+    def device_class(self):
+        """Return the class of this device."""
+        return DEFAULT_DEVICE_CLASS
+
+    @property
+    def device_state_attributes(self):
+        """Return the state attributes."""
+        attrs = {}
+
+        if self.aurora_data:
+            attrs["visibility_level"] = self.aurora_data.visibility_level
+            attrs["message"] = self.aurora_data.is_visible_text
+
+        return attrs
+
+    def update(self):
+        """Get the latest data from Aurora API and updates the states."""
+        self.aurora_data.update()
+
+
+class AuroraData(object):
+    """Get aurora forecast."""
+
+    def __init__(self, latitude, longitude, threshold):
+        """Initialize the data object."""
+        self.latitude = latitude
+        self.longitude = longitude
+        self.number_of_latitude_intervals = 513
+        self.number_of_longitude_intervals = 1024
+        self.api_url = \
+            "http://services.swpc.noaa.gov/text/aurora-nowcast-map.txt"
+        self.headers = {"User-Agent": "Home Assistant Aurora Tracker v.0.1.0"}
+
+        self.threshold = int(threshold)
+        self.is_visible = None
+        self.is_visible_text = None
+        self.visibility_level = None
+
+    @Throttle(MIN_TIME_BETWEEN_UPDATES)
+    def update(self):
+        """Get the latest data from the Aurora service."""
+        try:
+            self.visibility_level = self.get_aurora_forecast()
+            if int(self.visibility_level) > self.threshold:
+                self.is_visible = True
+                self.is_visible_text = "visible!"
+            else:
+                self.is_visible = False
+                self.is_visible_text = "nothing's out"
+
+        except requests.exceptions.HTTPError as error:
+            _LOGGER.error(
+                "Connection to aurora forecast service failed: %s", error)
+            return False
+
+    def get_aurora_forecast(self):
+        """Get forecast data and parse for given long/lat."""
+        raw_data = requests.get(self.api_url, headers=self.headers).text
+        forecast_table = [
+            row.strip(" ").split("   ")
+            for row in raw_data.split("\n")
+            if not row.startswith("#")
+        ]
+
+        # convert lat and long for data points in table
+        converted_latitude = round((self.latitude / 180)
+                                   * self.number_of_latitude_intervals)
+        converted_longitude = round((self.longitude / 360)
+                                    * self.number_of_longitude_intervals)
+
+        return forecast_table[converted_latitude][converted_longitude]