[fineoffsetweatherstation] Implement new measurand free-stack-size

Signed-off-by: Andreas Berger <andreas@berger-freelancer.com>

bundles/org.openhab.binding.fineoffsetweatherstation/README.md

@@ -19,15 +19,15 @@ Here is a product picture of how this Weather Station looks like:
 
 ![WH2650](doc/WH2650.png)
 
-This binding works offline by [implementing the wire protocol](https://osswww.ecowitt.net/uploads/20220407/WN1900%20GW1000,1100%20WH2680,2650%20telenet%20v1.6.4.pdf) of the WiFi gateway device.
+This binding works offline by [implementing the wire protocol](https://community.openhab.org/uploads/short-url/cuV8oOaCYHZhdm0hVJUN7hxMMfe.pdf) of the WiFi gateway device.
 
 ## Discussion
 
 If you have any issues or feedback, please feel free to [get in touch via the community forum](https://community.openhab.org/t/fine-offset-weather-station-binding-discussion/134167)
 
 ## Supported Things
 
-- `weatherstation`: A Fine Offset gateway device with the ThingTypeUID `fineoffsetweatherstation:weatherstation` which supports the [wire protocol](https://osswww.ecowitt.net/uploads/20220407/WN1900%20GW1000,1100%20WH2680,2650%20telenet%20v1.6.4.pdf) e.g.:
+- `weatherstation`: A Fine Offset gateway device with the ThingTypeUID `fineoffsetweatherstation:weatherstation` which supports the [wire protocol](https://community.openhab.org/uploads/short-url/cuV8oOaCYHZhdm0hVJUN7hxMMfe.pdf) e.g.:
   - HP2550
   - HP3500
   - GW1000
@@ -280,6 +280,7 @@ Valid sensors:
 | piezo-rain-week                       | Number:Length        | R          | Piezo - Rainfall this Week                     |
 | piezo-rain-month                      | Number:Length        | R          | Piezo - Rainfall this Month                    |
 | piezo-rain-year                       | Number:Length        | R          | Piezo - Rainfall this Year                     |
+| free-heap-size                        | Number:Dimensionless | R          | Free Stack Size                                |
 
 NOTE: Not every gateway provides all available data, even if they are displayed in the WS-View app.
 Especially the channels `temperature-dew-point` or `temperature-wind-chill` are derived from other measured values.

bundles/org.openhab.binding.fineoffsetweatherstation/src/main/java/org/openhab/binding/fineoffsetweatherstation/internal/FineOffsetWeatherStationBindingConstants.java

@@ -54,6 +54,8 @@ public class FineOffsetWeatherStationBindingConstants {
     public static final ChannelTypeUID CHANNEL_TYPE_LIGHTNING_DISTANCE = new ChannelTypeUID(BINDING_ID,
             "lightning-distance");
 
+    public static final ChannelTypeUID CHANNEL_TYPE_FREE_STACK_SIZE = new ChannelTypeUID(BINDING_ID, "free-stack-size");
+
     public static final Set<ThingTypeUID> SUPPORTED_THING_TYPES_UIDS = Set.of(THING_TYPE_GATEWAY, THING_TYPE_SENSOR);
 
     public static final String SENSOR_CHANNEL_SIGNAL = "signal";

bundles/org.openhab.binding.fineoffsetweatherstation/src/main/java/org/openhab/binding/fineoffsetweatherstation/internal/domain/Measurand.java

@@ -12,6 +12,7 @@
  */
 package org.openhab.binding.fineoffsetweatherstation.internal.domain;
 
+import static org.openhab.binding.fineoffsetweatherstation.internal.FineOffsetWeatherStationBindingConstants.CHANNEL_TYPE_FREE_STACK_SIZE;
 import static org.openhab.binding.fineoffsetweatherstation.internal.FineOffsetWeatherStationBindingConstants.CHANNEL_TYPE_MAX_WIND_SPEED;
 import static org.openhab.binding.fineoffsetweatherstation.internal.FineOffsetWeatherStationBindingConstants.CHANNEL_TYPE_MOISTURE;
 import static org.openhab.binding.fineoffsetweatherstation.internal.FineOffsetWeatherStationBindingConstants.CHANNEL_TYPE_UV_INDEX;
@@ -143,6 +144,9 @@ public enum Measurand {
             // skip battery-level, since it is read via Command.CMD_READ_SENSOR_ID_NEW
             new Skip(1)),
 
+    // This is for heap : the available stack top. If it is reducing, it means the stack is using up.
+    ITEM_HEAP_FREE("free-heap-size", 0x6c, "Free Heap Size", MeasureType.INTEGER, CHANNEL_TYPE_FREE_STACK_SIZE),
+
     ITEM_SENSOR_CO2(0x70,
             new MeasurandParser("sensor-co2-temperature", "Temperature (CO₂-Sensor)", MeasureType.TEMPERATURE),
             new MeasurandParser("sensor-co2-humidity", "Humidity (CO₂-Sensor)", MeasureType.PERCENTAGE),

bundles/org.openhab.binding.fineoffsetweatherstation/src/main/java/org/openhab/binding/fineoffsetweatherstation/internal/domain/MeasureType.java

@@ -122,6 +122,7 @@ public enum MeasureType {
             (data, offset) -> Utils.toUInt16(data, offset) / 10.),
 
     BYTE(1, null, (data, offset, context) -> new DecimalType(toUInt8(data[offset]))),
+    INTEGER(4, null, (data, offset, context) -> new DecimalType(toUInt32(data, offset))),
 
     DATE_TIME2(6, null, (data, offset, context) -> new DateTimeType(
             ZonedDateTime.ofInstant(Instant.ofEpochSecond(toUInt32(data, offset)), context.getZoneId())));

bundles/org.openhab.binding.fineoffsetweatherstation/src/main/resources/OH-INF/i18n/fineoffsetweatherstation.properties

@@ -30,6 +30,8 @@ channel-type.fineoffsetweatherstation.battery-voltage.label = Battery Voltage
 channel-type.fineoffsetweatherstation.battery-voltage.description = The voltage of the battery
 channel-type.fineoffsetweatherstation.co2.label = CO₂
 channel-type.fineoffsetweatherstation.co2.description = Air Quality Indicator
+channel-type.fineoffsetweatherstation.free-stack-size.description = The available stack size. If it is reducing, it means the stack is using up.
+channel-type.fineoffsetweatherstation.free-stack-size.label = Free Stack Size
 channel-type.fineoffsetweatherstation.humidity.label = Humidity
 channel-type.fineoffsetweatherstation.illumination.label = Illumination
 channel-type.fineoffsetweatherstation.lightning-counter.label = Lightning Counter
@@ -136,3 +138,4 @@ gateway.dynamic-channel.piezo-rain-day.label = Rain Day
 gateway.dynamic-channel.piezo-rain-week.label = Rain Week
 gateway.dynamic-channel.piezo-rain-month.label = Rain Month
 gateway.dynamic-channel.piezo-rain-year.label = Rain Year
+gateway.dynamic-channel.free-heap-size.label = Free Stack Size

bundles/org.openhab.binding.fineoffsetweatherstation/src/main/resources/OH-INF/thing/gateway.xml

@@ -180,4 +180,10 @@
 		<label>Lightning Distance</label>
 		<state pattern="%.0f %unit%" readOnly="true"/>
 	</channel-type>
+
+	<channel-type id="free-stack-size">
+		<item-type>Number:Dimensionless</item-type>
+		<label>Free Stack Size</label>
+		<description>The available stack size. If it is reducing, it means the stack is using up.</description>
+	</channel-type>
 </thing:thing-descriptions>

bundles/org.openhab.binding.fineoffsetweatherstation/src/test/java/org/openhab/binding/fineoffsetweatherstation/internal/service/FineOffsetDataParserTest.java

@@ -1,13 +1,13 @@
 /**
  * Copyright (c) 2010-2024 Contributors to the openHAB project
- *
+ * <p>
  * See the NOTICE file(s) distributed with this work for additional
  * information.
- *
+ * <p>
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
  * http://www.eclipse.org/legal/epl-2.0
- *
+ * <p>
  * SPDX-License-Identifier: EPL-2.0
  */
 package org.openhab.binding.fineoffsetweatherstation.internal.service;
@@ -123,6 +123,24 @@ void testLiveDataWH34AndWh45() {
                         new Tuple("sensor-co2-co2-24-hour-average", "891 ppm"));
     }
 
+    @Test
+    void testLiveDataWithHeapFreeMeasurand() {
+        byte[] bytes = HexUtils.hexToBytes(
+                "FFFF27002F01010B062A0826C10926C1020011074D0A004C0B000C0C000D15000226C816006317011900136C0001FED864");
+        DebugDetails debugDetails = new DebugDetails(bytes, Command.CMD_GW1000_LIVEDATA, Protocol.DEFAULT);
+        List<MeasuredValue> data = new FineOffsetDataParser(Protocol.DEFAULT).getMeasuredValues(bytes,
+                new ConversionContext(ZoneOffset.UTC), debugDetails);
+        Assertions.assertThat(data)
+                .extracting(MeasuredValue::getChannelId, measuredValue -> measuredValue.getState().toString())
+                .containsExactly(new Tuple("temperature-indoor", "26.7 °C"), new Tuple("humidity-indoor", "42 %"),
+                        new Tuple("pressure-absolute", "992.1 hPa"), new Tuple("pressure-relative", "992.1 hPa"),
+                        new Tuple("temperature-outdoor", "1.7 °C"), new Tuple("humidity-outdoor", "77 %"),
+                        new Tuple("direction-wind", "76 °"), new Tuple("speed-wind", "1.2 m/s"),
+                        new Tuple("speed-gust", "1.3 m/s"), new Tuple("illumination", "14100 lx"),
+                        new Tuple("irradiation-uv", "9.9 mW/m²"), new Tuple("uv-index", "1"),
+                        new Tuple("wind-max-day", "1.9 m/s"), new Tuple("free-heap-size", "130776"));
+    }
+
     @Test
     void testLiveDataELV() {
         byte[] data = HexUtils.hexToBytes(