[hue] Lamp handler exposes min/max Colour Temperature in state description (#17637)

* [hue] provide color temperature min/max values dynamically in state description

Signed-off-by: AndrewFG <software@whitebear.ch>

bundles/org.openhab.binding.hue/src/main/java/org/openhab/binding/hue/internal/handler/Clip2StateDescriptionProvider.java

@@ -12,19 +12,32 @@
  */
 package org.openhab.binding.hue.internal.handler;
 
+import java.math.BigDecimal;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
 import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
 import org.openhab.core.events.EventPublisher;
+import org.openhab.core.thing.Channel;
+import org.openhab.core.thing.ChannelUID;
 import org.openhab.core.thing.binding.BaseDynamicStateDescriptionProvider;
+import org.openhab.core.thing.events.ThingEventFactory;
 import org.openhab.core.thing.i18n.ChannelTypeI18nLocalizationService;
 import org.openhab.core.thing.link.ItemChannelLinkRegistry;
 import org.openhab.core.thing.type.DynamicStateDescriptionProvider;
+import org.openhab.core.types.StateDescription;
+import org.openhab.core.types.StateDescriptionFragment;
+import org.openhab.core.types.StateDescriptionFragmentBuilder;
 import org.osgi.service.component.annotations.Activate;
 import org.osgi.service.component.annotations.Component;
 import org.osgi.service.component.annotations.Reference;
 
 /**
- * The {@link Clip2StateDescriptionProvider} provides dynamic state descriptions of scene channels whose list of options
+ * The {@link Clip2StateDescriptionProvider} provides dynamic state descriptions of alert, effect, scene, and colour
- * is determined at runtime.
+ * temperature channels whose capabilities are dynamically determined at runtime.
  *
  * @author Andrew Fiddian-Green - Initial contribution
  *
@@ -33,6 +46,8 @@ import org.osgi.service.component.annotations.Reference;
 @Component(service = { DynamicStateDescriptionProvider.class, Clip2StateDescriptionProvider.class })
 public class Clip2StateDescriptionProvider extends BaseDynamicStateDescriptionProvider {
 
+    private final Map<ChannelUID, StateDescriptionFragment> stateDescriptionFragments = new ConcurrentHashMap<>();
+
     @Activate
     public Clip2StateDescriptionProvider(final @Reference EventPublisher eventPublisher,
             final @Reference ItemChannelLinkRegistry itemChannelLinkRegistry,
@@ -41,4 +56,29 @@ public class Clip2StateDescriptionProvider extends BaseDynamicStateDescriptionPr
         this.itemChannelLinkRegistry = itemChannelLinkRegistry;
         this.channelTypeI18nLocalizationService = channelTypeI18nLocalizationService;
     }
+
+    @Override
+    public @Nullable StateDescription getStateDescription(Channel channel, @Nullable StateDescription original,
+            @Nullable Locale locale) {
+        StateDescriptionFragment stateDescriptionFragment = stateDescriptionFragments.get(channel.getUID());
+        return stateDescriptionFragment != null ? stateDescriptionFragment.toStateDescription()
+                : super.getStateDescription(channel, original, locale);
+    }
+
+    /**
+     * Set the state description minimum and maximum values and pattern in Kelvin for the given channel UID
+     */
+    public void setMinMaxKelvin(ChannelUID channelUID, long minKelvin, long maxKelvin) {
+        StateDescriptionFragment oldStateDescriptionFragment = stateDescriptionFragments.get(channelUID);
+        StateDescriptionFragment newStateDescriptionFragment = StateDescriptionFragmentBuilder.create()
+                .withMinimum(BigDecimal.valueOf(minKelvin)).withMaximum(BigDecimal.valueOf(maxKelvin))
+                .withStep(BigDecimal.valueOf(100)).withPattern("%.0f K").build();
+        if (!newStateDescriptionFragment.equals(oldStateDescriptionFragment)) {
+            stateDescriptionFragments.put(channelUID, newStateDescriptionFragment);
+            ItemChannelLinkRegistry itemChannelLinkRegistry = this.itemChannelLinkRegistry;
+            postEvent(ThingEventFactory.createChannelDescriptionChangedEvent(channelUID,
+                    itemChannelLinkRegistry != null ? itemChannelLinkRegistry.getLinkedItemNames(channelUID) : Set.of(),
+                    newStateDescriptionFragment, oldStateDescriptionFragment));
+        }
+    }
 }

bundles/org.openhab.binding.hue/src/main/java/org/openhab/binding/hue/internal/handler/Clip2ThingHandler.java

@@ -38,6 +38,7 @@ import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.eclipse.jdt.annotation.Nullable;
 import org.openhab.binding.hue.internal.action.DynamicsActions;
 import org.openhab.binding.hue.internal.api.dto.clip2.Alerts;
+import org.openhab.binding.hue.internal.api.dto.clip2.ColorTemperature;
 import org.openhab.binding.hue.internal.api.dto.clip2.ColorXy;
 import org.openhab.binding.hue.internal.api.dto.clip2.Dimming;
 import org.openhab.binding.hue.internal.api.dto.clip2.Effects;
@@ -945,6 +946,7 @@ public class Clip2ThingHandler extends BaseThingHandler {
             case LIGHT:
                 if (fullUpdate) {
                     updateEffectChannel(resource);
+                    updateColorTemperatureAbsoluteChannel(resource);
                 }
                 updateState(CHANNEL_2_COLOR_TEMP_PERCENT, resource.getColorTemperaturePercentState(), fullUpdate);
                 updateState(CHANNEL_2_COLOR_TEMP_ABSOLUTE, resource.getColorTemperatureAbsoluteState(), fullUpdate);
@@ -1114,6 +1116,24 @@ public class Clip2ThingHandler extends BaseThingHandler {
         }
     }
 
+    /**
+     * Process the incoming Resource to initialize the colour temperature absolute channel's state description based on
+     * the minimum and maximum values supported by the lamp's Mirek schema.
+     *
+     * @param resource a Resource possibly containing a color temperature element and respective Mirek schema element.
+     */
+    private void updateColorTemperatureAbsoluteChannel(Resource resource) {
+        ColorTemperature colorTemperature = resource.getColorTemperature();
+        if (colorTemperature != null) {
+            MirekSchema mirekSchema = colorTemperature.getMirekSchema();
+            if (mirekSchema != null) {
+                stateDescriptionProvider.setMinMaxKelvin(new ChannelUID(thing.getUID(), CHANNEL_2_COLOR_TEMP_ABSOLUTE),
+                        1000000 / mirekSchema.getMirekMaximum(), 1000000 / mirekSchema.getMirekMinimum());
+                logger.debug("{} -> updateColorTempAbsChannel() done", resource.getId());
+            }
+        }
+    }
+
     /**
      * Update the light properties.
      *