Health Connect: Exclude bad-measurement sentinels from HR and SpO2 sync

PR #6195 widened the syncer guards to match Health Connect's enforced
bounds, but widened too much: it overlooked that some of Gadgetbridge's
in-band sentinel values fall inside HC's accepted range, so placeholder
readings leaked into Health Connect and showed up as spurious data points.

- HeartRate / RestingHeartRate: 255 is GB's "illegal value" marker for a
  bad measurement (ActivitySample.getHeartRate), and it sits inside HC's
  1..300 / 0..300 range. Exclude it explicitly while keeping HC's bounds.
- SpO2: 0 means "not measured" (sample providers return null on 0 and all
  SpO2 charts filter getSpo2() > 0). Raise the lower bound to 1.

Add HeartRateSyncerTest covering the HeartRateSyncer.sync() path (sentinel
255 and 0 are not inserted; valid range passes) and extend
SyncerRangeValidationTest with the new boundaries.

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/healthconnect/syncers/HeartRateSync.kt

@@ -52,11 +52,12 @@ internal object HeartRateSyncer : ActivitySampleSyncer {
             return SyncerStatistics(recordType = "HeartRate")
         }
 
-        // 2. Relevant Input Data Check (HC enforces 1..300 bpm)
+        // 2. Relevant Input Data Check. HC enforces 1..300 bpm; 255 is GB's documented
+        // "illegal value" sentinel (ActivitySample.getHeartRate) and lands inside that range.
         var droppedOutOfRange = 0
         val validHRSamples = deviceSamples
             .filter {
-                val inRange = it.heartRate in 1..300
+                val inRange = it.heartRate in 1..300 && it.heartRate != 255
                 // 0 means "not measured" - common, don't count as out-of-range
                 if (!inRange && it.heartRate != 0) {
                     droppedOutOfRange++
@@ -66,7 +67,7 @@ internal object HeartRateSyncer : ActivitySampleSyncer {
             .sortedBy { it.timestamp }
         if (droppedOutOfRange > 0) {
             LOG.info(
-                "${HealthConnectUtils.HC_SYNC_TAG} Dropped {} out-of-range HeartRate sample(s) for device '{}' in slice {} to {} (HC requires 1..300 bpm).",
+                "${HealthConnectUtils.HC_SYNC_TAG} Dropped {} out-of-range HeartRate sample(s) for device '{}' in slice {} to {} (HC requires 1..300 bpm, 255 excluded as bad-measurement sentinel).",
                 droppedOutOfRange, deviceName, sliceStartBoundary, sliceEndBoundary
             )
         }

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/healthconnect/syncers/RestingHeartRateSyncer.kt

@@ -45,8 +45,9 @@ internal object RestingHeartRateSyncer : AbstractTimeSampleSyncer<HeartRateSampl
         metadata: Metadata,
         deviceName: String
     ): RestingHeartRateRecord? {
-        if (sample.heartRate !in 0..300) {
-            logger.skipOutOfRange(deviceName, "RestingHeartRate", sample.heartRate, "0..300 bpm")
+        // HC enforces 0..300 bpm; exclude 255, the bad-measurement sentinel GB uses for HR values.
+        if (sample.heartRate !in 0..300 || sample.heartRate == 255) {
+            logger.skipOutOfRange(deviceName, "RestingHeartRate", sample.heartRate, "0..300 bpm (255 excluded)")
             return null
         }
 

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/healthconnect/syncers/Spo2Syncer.kt

@@ -48,8 +48,9 @@ internal object Spo2Syncer : AbstractTimeSampleSyncer<Spo2Sample, OxygenSaturati
     ): OxygenSaturationRecord? {
         val spo2AsDouble = sample.spo2.toDouble()
 
-        if (spo2AsDouble !in 0.0..100.0 || !spo2AsDouble.isFinite()) {
-            logger.skipOutOfRange(deviceName, "SpO2", spo2AsDouble, "0..100 %")
+        // 0 means "not measured" in GB (charts filter getSpo2() > 0); exclude it.
+        if (spo2AsDouble !in 1.0..100.0 || !spo2AsDouble.isFinite()) {
+            logger.skipOutOfRange(deviceName, "SpO2", spo2AsDouble, "1..100 %")
             return null
         }
 

app/src/test/java/nodomain/freeyourgadget/gadgetbridge/util/healthconnect/syncers/HeartRateSyncerTest.kt

@@ -0,0 +1,119 @@
+package nodomain.freeyourgadget.gadgetbridge.util.healthconnect.syncers
+
+import androidx.health.connect.client.HealthConnectClient
+import androidx.health.connect.client.PermissionController
+import androidx.health.connect.client.aggregate.AggregationResult
+import androidx.health.connect.client.aggregate.AggregationResultGroupedByDuration
+import androidx.health.connect.client.aggregate.AggregationResultGroupedByPeriod
+import androidx.health.connect.client.permission.HealthPermission
+import androidx.health.connect.client.records.HeartRateRecord
+import androidx.health.connect.client.records.Record
+import androidx.health.connect.client.records.metadata.Device
+import androidx.health.connect.client.records.metadata.Metadata
+import androidx.health.connect.client.request.AggregateGroupByDurationRequest
+import androidx.health.connect.client.request.AggregateGroupByPeriodRequest
+import androidx.health.connect.client.request.AggregateRequest
+import androidx.health.connect.client.request.ChangesTokenRequest
+import androidx.health.connect.client.request.ReadRecordsRequest
+import androidx.health.connect.client.response.ChangesResponse
+import androidx.health.connect.client.response.InsertRecordsResponse
+import androidx.health.connect.client.response.ReadRecordResponse
+import androidx.health.connect.client.response.ReadRecordsResponse
+import androidx.health.connect.client.time.TimeRangeFilter
+import kotlinx.coroutines.runBlocking
+import nodomain.freeyourgadget.gadgetbridge.impl.GBDevice
+import nodomain.freeyourgadget.gadgetbridge.model.ActivityKind
+import nodomain.freeyourgadget.gadgetbridge.model.ActivitySample
+import nodomain.freeyourgadget.gadgetbridge.model.DeviceType
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import java.time.Instant
+import java.time.ZoneId
+import kotlin.reflect.KClass
+
+class HeartRateSyncerTest {
+
+    private val zoneId: ZoneId = ZoneId.of("UTC")
+    private val gbDevice = GBDevice("00:11:22:33:44:55", "Testie", "Testie Alias", "Test Folder", DeviceType.TEST)
+    private val metadata: Metadata = Metadata.unknownRecordingMethod(
+        Device(type = Device.TYPE_WATCH, manufacturer = "test", model = "test")
+    )
+    private val grantedPermissions = setOf(HealthPermission.getWritePermission(HeartRateRecord::class))
+
+    private fun hrSample(ts: Int, bpm: Int): ActivitySample =
+        object : ActivitySample {
+            override fun getTimestamp(): Int = ts
+            override fun getProvider(): nodomain.freeyourgadget.gadgetbridge.devices.SampleProvider<*>? = null
+            override fun getRawKind(): Int = ActivityKind.UNKNOWN.code
+            override fun getKind(): ActivityKind = ActivityKind.UNKNOWN
+            override fun getRawIntensity(): Int = 0
+            override fun getIntensity(): Float = 0f
+            override fun getSteps(): Int = 0
+            override fun getDistanceCm(): Int = 0
+            override fun getActiveCalories(): Int = 0
+            override fun getHeartRate(): Int = bpm
+            override fun setHeartRate(value: Int) {}
+        }
+
+    private fun syncBpm(values: List<Int>): List<Long> {
+        val baseTs = 1_700_000_000
+        val samples = values.mapIndexed { i, bpm -> hrSample(baseTs + i * 60, bpm) }
+        val start = Instant.ofEpochSecond(baseTs.toLong())
+        val end = Instant.ofEpochSecond(baseTs.toLong() + values.size * 60L)
+        val client = CapturingClient()
+        runBlocking {
+            HeartRateSyncer.sync(client, gbDevice, metadata, zoneId, start, end, grantedPermissions, samples)
+        }
+        return client.inserted
+            .filterIsInstance<HeartRateRecord>()
+            .flatMap { it.samples }
+            .map { it.beatsPerMinute }
+    }
+
+    @Test
+    fun sentinel255_isNotSynced() {
+        val bpm = syncBpm(listOf(60, 255, 62))
+        assertTrue("255 sentinel must not reach Health Connect", 255L !in bpm)
+        assertEquals(listOf(60L, 62L), bpm)
+    }
+
+    @Test
+    fun zero_isNotSynced() {
+        val bpm = syncBpm(listOf(60, 0, 62))
+        assertEquals(listOf(60L, 62L), bpm)
+    }
+
+    @Test
+    fun validRange_isSynced() {
+        val bpm = syncBpm(listOf(1, 300))
+        assertEquals(listOf(1L, 300L), bpm)
+    }
+
+    @Test
+    fun aboveHcLimit_isNotSynced() {
+        val bpm = syncBpm(listOf(60, 301, 62))
+        assertEquals(listOf(60L, 62L), bpm)
+    }
+
+    private class CapturingClient : HealthConnectClient {
+        val inserted = mutableListOf<Record>()
+
+        override suspend fun insertRecords(records: List<Record>): InsertRecordsResponse {
+            inserted.addAll(records)
+            return InsertRecordsResponse(records.map { "id" })
+        }
+
+        override val permissionController: PermissionController get() = throw NotImplementedError()
+        override suspend fun updateRecords(records: List<Record>) = throw NotImplementedError()
+        override suspend fun deleteRecords(recordType: KClass<out Record>, recordIdsList: List<String>, clientRecordIdsList: List<String>) = throw NotImplementedError()
+        override suspend fun deleteRecords(recordType: KClass<out Record>, timeRangeFilter: TimeRangeFilter) = throw NotImplementedError()
+        override suspend fun <T : Record> readRecord(recordType: KClass<T>, recordId: String): ReadRecordResponse<T> = throw NotImplementedError()
+        override suspend fun <T : Record> readRecords(request: ReadRecordsRequest<T>): ReadRecordsResponse<T> = throw NotImplementedError()
+        override suspend fun aggregate(request: AggregateRequest): AggregationResult = throw NotImplementedError()
+        override suspend fun aggregateGroupByDuration(request: AggregateGroupByDurationRequest): List<AggregationResultGroupedByDuration> = throw NotImplementedError()
+        override suspend fun aggregateGroupByPeriod(request: AggregateGroupByPeriodRequest): List<AggregationResultGroupedByPeriod> = throw NotImplementedError()
+        override suspend fun getChangesToken(request: ChangesTokenRequest): String = throw NotImplementedError()
+        override suspend fun getChanges(changesToken: String): ChangesResponse = throw NotImplementedError()
+    }
+}

app/src/test/java/nodomain/freeyourgadget/gadgetbridge/util/healthconnect/syncers/SyncerRangeValidationTest.kt

@@ -158,7 +158,12 @@ class SyncerRangeValidationTest {
 
     @Test
     fun spo2_lowerBoundary_accepted() {
-        assertNotNull(Spo2Syncer.convertSample(spo2Sample(0), offset, metadata, device))
+        assertNotNull(Spo2Syncer.convertSample(spo2Sample(1), offset, metadata, device))
+    }
+
+    @Test
+    fun spo2_zero_dropped() {
+        assertNull(Spo2Syncer.convertSample(spo2Sample(0), offset, metadata, device))
     }
 
     @Test
@@ -199,6 +204,11 @@ class SyncerRangeValidationTest {
         assertNull(RestingHeartRateSyncer.convertSample(hrSample(301), offset, metadata, device))
     }
 
+    @Test
+    fun restingHr_sentinel255_dropped() {
+        assertNull(RestingHeartRateSyncer.convertSample(hrSample(255), offset, metadata, device))
+    }
+
     @Test
     fun restingHr_negative_dropped() {
         assertNull(RestingHeartRateSyncer.convertSample(hrSample(-1), offset, metadata, device))