Astro Background discovery for location changes

extensions/binding/org.eclipse.smarthome.binding.astro/README.md

@@ -10,17 +10,19 @@ This binding supports two Things: Sun and Moon
 
 ## Discovery
 
-Discovery is not necessary, because all calculations are done within the binding.
+If you have a location set (see for ex. PaperUI: "Configuration - System - Regional Settings - Location"), this will automatically create a "Local Sun" and a "Local Moon" item for this location.
+
+If you change your system location the background discovery detects this change and applies it to the "Local Sun" and a "Local Moon" items automatically.
 
 ## Binding Configuration
 
 No binding configuration required.
 
 ## Thing Configuration
 
-A thing requires the geolocation (latitude, longitude) for which the calculation is done.
+A thing requires the geolocation (latitude,longitude[,altitude]) for which the calculation is done.
 Optionally, a refresh interval (in seconds) can be defined to also calculate positional data like azimuth and elevation.
-An complementary altitude (optional) configuration item can also be specified to sharpen results provided by Radiation group.
+The complementary altitude part of the geolocation parameter is optional and sharpens results provided by the Radiation group.
 
 ## Channels
 
@@ -123,26 +125,26 @@ sunrise is 22:10 but `latest` is set to 20:00 so the event/datetime value is mov
 Things:
 
 ```
-astro:sun:home  [ geolocation="xx.xxxxxx,xx.xxxxxx", altitude=100, interval=60 ]
-astro:moon:home [ geolocation="xx.xxxxxx,xx.xxxxxx", interval=60 ]
+astro:sun:home  [ geolocation="xx.xxxxxx,xx.xxxxxx,xx.xxx", interval=60 ]
+astro:moon:home [ geolocation="xx.xxxxxx,xx.xxxxxx,xx.xxx", interval=60 ]
 ```
 
 or optionally with an event offset
 
 ```
-astro:sun:home [ geolocation="xx.xxxxxx,xx.xxxxxx", altitude=100, interval=60 ] {
+astro:sun:home [ geolocation="xx.xxxxxx,xx.xxxxxx,xx.xxx", interval=60 ] {
     Channels:
         Type rangeEvent : rise#event [
             offset=-30
         ]
 }
-astro:moon:home [ geolocation="xx.xxxxxx,xx.xxxxxx", interval=60 ]
+astro:moon:home [ geolocation="xx.xxxxxx,xx.xxxxxx,xx.xxx", interval=60 ]
 ```
 
 or a datetime offset
 
 ```
-astro:sun:home [ geolocation="xx.xxxxxx,xx.xxxxxx", altitude=100, interval=60 ] {
+astro:sun:home [ geolocation="xx.xxxxxx,xx.xxxxxx,xx.xxx", interval=60 ] {
     Channels:
         Type start : rise#start [
             offset=5
@@ -156,7 +158,7 @@ astro:sun:home [ geolocation="xx.xxxxxx,xx.xxxxxx", altitude=100, interval=60 ]
 or a offset and latest
 
 ```
-astro:sun:home [ geolocation="xx.xxxxxx,xx.xxxxxx", altitude=100, interval=60 ] {
+astro:sun:home [ geolocation="xx.xxxxxx,xx.xxxxxx,xx.xxx", interval=60 ] {
     Channels:
         Type rangeEvent : rise#event [
             offset=-10,
@@ -187,3 +189,7 @@ then
     ...
 end
 ```
+
+## Tipps
+
+Do not worry if for example the "astro dawn" is "-" in the place that you set for your item. The reason might be that you live in a northern country and it is summer, because then by definition the sun is not 18 degrees below the horizon in the morning. For details see: https://en.wikipedia.org/wiki/Dawn Also while reading this wikipedia article you might come to the conclusion that you want to use "civil dawn" anyway.

extensions/binding/org.eclipse.smarthome.binding.astro/src/main/java/org/eclipse/smarthome/binding/astro/discovery/AstroDiscoveryService.java

@@ -11,8 +11,9 @@
 
 import java.util.Arrays;
 import java.util.HashSet;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
 
-import org.eclipse.smarthome.binding.astro.AstroBindingConstants;
 import org.eclipse.smarthome.config.discovery.AbstractDiscoveryService;
 import org.eclipse.smarthome.config.discovery.DiscoveryResultBuilder;
 import org.eclipse.smarthome.core.i18n.LocationProvider;
@@ -31,39 +32,69 @@
 public class AstroDiscoveryService extends AbstractDiscoveryService {
     private final Logger logger = LoggerFactory.getLogger(AstroDiscoveryService.class);
     private static final int DISCOVER_TIMEOUT_SECONDS = 30;
+    private static final int LOCATION_CHANGED_CHECK_INTERVAL = 60;
     private LocationProvider locationProvider;
+    private ScheduledFuture<?> astroDiscoveryJob;
+    private PointType previousLocation;
+
+    private static ThingUID SUN_THING = new ThingUID(THING_TYPE_SUN, LOCAL);
+    private static ThingUID MOON_THING = new ThingUID(THING_TYPE_MOON, LOCAL);
 
     /**
-     * Creates a AstroDiscoveryService with disabled autostart.
+     * Creates a AstroDiscoveryService with enabled autostart.
      */
     public AstroDiscoveryService() {
-        super(new HashSet<>(Arrays.asList(new ThingTypeUID(BINDING_ID, "-"))), DISCOVER_TIMEOUT_SECONDS, false);
+        super(new HashSet<>(Arrays.asList(new ThingTypeUID(BINDING_ID, "-"))), DISCOVER_TIMEOUT_SECONDS, true);
     }
 
     @Override
     protected void startScan() {
         logger.debug("Starting Astro discovery scan");
-
         PointType location = locationProvider.getLocation();
-
         if (location == null) {
             logger.debug("LocationProvider.getLocation() is not set -> Will not provide any discovery results");
             return;
         }
+        createResults(location);
+    }
 
-        ThingUID sunThing = new ThingUID(AstroBindingConstants.THING_TYPE_SUN, LOCAL);
-        ThingUID moonThing = new ThingUID(AstroBindingConstants.THING_TYPE_MOON, LOCAL);
+    @Override
+    protected void startBackgroundDiscovery() {
+        if (astroDiscoveryJob == null) {
+            astroDiscoveryJob = scheduler.scheduleAtFixedRate(() -> {
+                PointType currentLocation = locationProvider.getLocation();
+                if ((currentLocation != null) && !currentLocation.equals(previousLocation)) {
+                    logger.info("Location has been changed from {} to {}: Creating new Discovery Results",
+                            previousLocation, currentLocation);
+                    createResults(currentLocation);
+                    previousLocation = currentLocation;
+                }
+            }, 0, LOCATION_CHANGED_CHECK_INTERVAL, TimeUnit.SECONDS);
+            logger.debug("Scheduled astro location-changed job every {} seconds", LOCATION_CHANGED_CHECK_INTERVAL);
+        }
+    }
+
+    @Override
+    protected void stopBackgroundDiscovery() {
+        logger.debug("Stopping Astro device background discovery");
+        if (astroDiscoveryJob != null && !astroDiscoveryJob.isCancelled()) {
+            astroDiscoveryJob.cancel(true);
+            astroDiscoveryJob = null;
+            logger.debug("Stopped Astro device background discovery");
+        }
+    }
 
+    public void createResults(PointType location) {
         String propGeolocation;
         if (location.getAltitude() != null) {
             propGeolocation = String.format("%s,%s,%s", location.getLatitude(), location.getLongitude(),
                     location.getAltitude());
         } else {
             propGeolocation = String.format("%s,%s", location.getLatitude(), location.getLongitude());
         }
-        thingDiscovered(DiscoveryResultBuilder.create(sunThing).withLabel("Local Sun")
+        thingDiscovered(DiscoveryResultBuilder.create(SUN_THING).withLabel("Local Sun")
                 .withProperty("geolocation", propGeolocation).build());
-        thingDiscovered(DiscoveryResultBuilder.create(moonThing).withLabel("Local Moon")
+        thingDiscovered(DiscoveryResultBuilder.create(MOON_THING).withLabel("Local Moon")
                 .withProperty("geolocation", propGeolocation).build());
     }