feat(android): add heart rate BLE diagnostics

CHANGELOG.md

@@ -9,6 +9,14 @@
   consumed ACK, after which those stopped captures remain local history but are
   excluded from ordinary re-publication. Desktop/Web remain sensor consumers
   only; Bluetooth Classic Trainlog synchronization is unchanged.
+- Added the Android Heart Rate Service diagnostic foundation. The independent
+  `0x2A37` parser covers 8/16-bit BPM, contact, energy and raw RR flags with
+  strict malformed-payload rejection. A settings diagnostic provides bounded
+  HRS-filtered and expanded BLE scans, GATT service discovery and notification
+  subscription without turning desktop/Web into sensor clients. Android 12+
+  scan/connect permissions and the Android 11-and-older scan-location boundary
+  are explicit. Real armband notification characterization remains a hardware
+  validation gate before persistent acquisition.
 
 Development opened after stable v0.1.4 release.
 

android/app/src/main/AndroidManifest.xml

@@ -12,6 +12,14 @@
     <uses-permission
         android:name="android.permission.BLUETOOTH_ADMIN"
         android:maxSdkVersion="30" />
+    <!-- BLE cardio discovery does not derive physical location. Android 11 and
+         lower still require fine location for direct BLE scans. -->
+    <uses-permission
+        android:name="android.permission.ACCESS_FINE_LOCATION"
+        android:maxSdkVersion="30" />
+    <uses-permission
+        android:name="android.permission.BLUETOOTH_SCAN"
+        android:usesPermissionFlags="neverForLocation" />
     <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
     <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
     <uses-permission android:name="android.permission.FOREGROUND_SERVICE_DATA_SYNC" />

android/app/src/main/java/com/labfytools/trainlog/data/HeartRateBleDiagnostics.kt

@@ -0,0 +1,482 @@
+/*
+ * Android-only BLE Heart Rate diagnostics.
+ *
+ * This owner is intentionally bounded and screen-scoped. Long-running capture
+ * belongs to the later foreground acquisition service, not this diagnostic.
+ */
+package com.labfytools.trainlog.data
+
+import android.Manifest
+import android.annotation.SuppressLint
+import android.bluetooth.BluetoothDevice
+import android.bluetooth.BluetoothGatt
+import android.bluetooth.BluetoothGattCallback
+import android.bluetooth.BluetoothGattCharacteristic
+import android.bluetooth.BluetoothGattDescriptor
+import android.bluetooth.BluetoothManager
+import android.bluetooth.BluetoothProfile
+import android.bluetooth.BluetoothStatusCodes
+import android.bluetooth.le.ScanCallback
+import android.bluetooth.le.ScanFilter
+import android.bluetooth.le.ScanResult
+import android.bluetooth.le.ScanSettings
+import android.content.Context
+import android.content.pm.PackageManager
+import android.os.Build
+import android.os.Handler
+import android.os.Looper
+import android.os.ParcelUuid
+import androidx.core.content.ContextCompat
+import java.util.UUID
+
+internal val HEART_RATE_SERVICE_UUID: UUID =
+    UUID.fromString("0000180d-0000-1000-8000-00805f9b34fb")
+internal val HEART_RATE_MEASUREMENT_UUID: UUID =
+    UUID.fromString("00002a37-0000-1000-8000-00805f9b34fb")
+internal val BATTERY_SERVICE_UUID: UUID =
+    UUID.fromString("0000180f-0000-1000-8000-00805f9b34fb")
+private val CLIENT_CHARACTERISTIC_CONFIG_UUID: UUID =
+    UUID.fromString("00002902-0000-1000-8000-00805f9b34fb")
+
+internal enum class HeartRateDiagnosticPhase {
+    IDLE,
+    SCANNING,
+    CONNECTING,
+    DISCOVERING,
+    SUBSCRIBING,
+    RECEIVING,
+    DISCONNECTED,
+    ERROR,
+}
+
+internal data class HeartRateDiagnosticDevice(
+    val address: String,
+    val name: String?,
+    val rssi: Int,
+    val advertisesHeartRate: Boolean,
+)
+
+internal data class HeartRateDiagnosticSnapshot(
+    val phase: HeartRateDiagnosticPhase = HeartRateDiagnosticPhase.IDLE,
+    val devices: List<HeartRateDiagnosticDevice> = emptyList(),
+    val selectedAddress: String? = null,
+    val serviceFound: Boolean = false,
+    val measurementFound: Boolean = false,
+    val batteryServiceFound: Boolean = false,
+    val notificationCount: Int = 0,
+    val latestMeasurement: ParsedHeartRateMeasurement? = null,
+    val diagnostic: String? = null,
+)
+
+internal fun heartRateBleRuntimePermissions(): Array<String> =
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
+        arrayOf(Manifest.permission.BLUETOOTH_SCAN, Manifest.permission.BLUETOOTH_CONNECT)
+    } else {
+        arrayOf(Manifest.permission.ACCESS_FINE_LOCATION)
+    }
+
+internal fun hasHeartRateBleRuntimePermissions(context: Context): Boolean =
+    heartRateBleRuntimePermissions().all {
+        ContextCompat.checkSelfPermission(context, it) == PackageManager.PERMISSION_GRANTED
+    }
+
+internal class HeartRateBleDiagnostics(
+    context: Context,
+    private val onSnapshot: (HeartRateDiagnosticSnapshot) -> Unit,
+) : AutoCloseable {
+    private val appContext = context.applicationContext
+    private val main = Handler(Looper.getMainLooper())
+    private val bluetoothManager =
+        appContext.getSystemService(BluetoothManager::class.java)
+    private val adapter get() = bluetoothManager?.adapter
+    private val devices = linkedMapOf<String, BluetoothDevice>()
+    private var snapshot = HeartRateDiagnosticSnapshot()
+    private var scannerCallback: ScanCallback? = null
+    private var scanStop: Runnable? = null
+    private var gatt: BluetoothGatt? = null
+    private var closed = false
+
+    private fun update(transform: (HeartRateDiagnosticSnapshot) -> HeartRateDiagnosticSnapshot) {
+        if (closed) return
+        if (Looper.myLooper() != Looper.getMainLooper()) {
+            main.post { update(transform) }
+            return
+        }
+        snapshot = transform(snapshot)
+        onSnapshot(snapshot)
+    }
+
+    @SuppressLint("MissingPermission")
+    fun startScan(includeAllBle: Boolean = false) {
+        if (!hasHeartRateBleRuntimePermissions(appContext)) {
+            update { it.copy(phase = HeartRateDiagnosticPhase.ERROR, diagnostic = "permission") }
+            return
+        }
+        val currentAdapter = adapter
+        if (currentAdapter == null) {
+            update { it.copy(phase = HeartRateDiagnosticPhase.ERROR, diagnostic = "bluetooth_unavailable") }
+            return
+        }
+        if (!currentAdapter.isEnabled) {
+            update { it.copy(phase = HeartRateDiagnosticPhase.ERROR, diagnostic = "bluetooth_disabled") }
+            return
+        }
+        val scanner = currentAdapter.bluetoothLeScanner
+        if (scanner == null) {
+            update { it.copy(phase = HeartRateDiagnosticPhase.ERROR, diagnostic = "scanner_unavailable") }
+            return
+        }
+
+        stopScan()
+        devices.clear()
+        update {
+            HeartRateDiagnosticSnapshot(
+                phase = HeartRateDiagnosticPhase.SCANNING,
+                diagnostic = if (includeAllBle) "scan_all" else "scan_heart_rate",
+            )
+        }
+
+        val callback =
+            object : ScanCallback() {
+                override fun onScanResult(callbackType: Int, result: ScanResult) {
+                    handleScanResult(result)
+                }
+
+                override fun onBatchScanResults(results: MutableList<ScanResult>) {
+                    results.forEach(::handleScanResult)
+                }
+
+                override fun onScanFailed(errorCode: Int) {
+                    update {
+                        it.copy(
+                            phase = HeartRateDiagnosticPhase.ERROR,
+                            diagnostic = "scan_failed:" + errorCode,
+                        )
+                    }
+                }
+            }
+        scannerCallback = callback
+        val filters =
+            if (includeAllBle) {
+                emptyList()
+            } else {
+                listOf(
+                    ScanFilter.Builder()
+                        .setServiceUuid(ParcelUuid(HEART_RATE_SERVICE_UUID))
+                        .build(),
+                )
+            }
+        scanner.startScan(
+            filters,
+            ScanSettings.Builder().setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY).build(),
+            callback,
+        )
+        val stopper =
+            Runnable {
+                if (snapshot.phase == HeartRateDiagnosticPhase.SCANNING) {
+                    stopScan()
+                    update { it.copy(phase = HeartRateDiagnosticPhase.IDLE, diagnostic = "scan_complete") }
+                }
+            }
+        scanStop = stopper
+        main.postDelayed(stopper, SCAN_DURATION_MS)
+    }
+
+    @SuppressLint("MissingPermission")
+    private fun handleScanResult(result: ScanResult) {
+        val record = result.scanRecord
+        val advertised =
+            record?.serviceUuids?.any { it.uuid == HEART_RATE_SERVICE_UUID } == true
+        val device = result.device
+        devices[device.address] = device
+        val row =
+            HeartRateDiagnosticDevice(
+                address = device.address,
+                name = record?.deviceName,
+                rssi = result.rssi,
+                advertisesHeartRate = advertised,
+            )
+        update { old ->
+            val rows =
+                (old.devices.filterNot { it.address == row.address } + row)
+                    .sortedWith(
+                        compareByDescending<HeartRateDiagnosticDevice> { it.advertisesHeartRate }
+                            .thenByDescending { it.rssi },
+                    )
+            old.copy(devices = rows)
+        }
+    }
+
+    @SuppressLint("MissingPermission")
+    fun connect(address: String) {
+        if (!hasHeartRateBleRuntimePermissions(appContext)) {
+            update { it.copy(phase = HeartRateDiagnosticPhase.ERROR, diagnostic = "permission") }
+            return
+        }
+        val device =
+            devices[address]
+                ?: runCatching { adapter?.getRemoteDevice(address) }.getOrNull()
+                ?: run {
+                    update { it.copy(phase = HeartRateDiagnosticPhase.ERROR, diagnostic = "device_missing") }
+                    return
+                }
+        stopScan()
+        closeGatt()
+        update {
+            it.copy(
+                phase = HeartRateDiagnosticPhase.CONNECTING,
+                selectedAddress = address,
+                serviceFound = false,
+                measurementFound = false,
+                batteryServiceFound = false,
+                notificationCount = 0,
+                latestMeasurement = null,
+                diagnostic = "connecting",
+            )
+        }
+        @Suppress("DEPRECATION")
+        runCatching {
+                device.connectGatt(
+                    appContext,
+                    false,
+                    gattCallback,
+                    BluetoothDevice.TRANSPORT_LE,
+                )
+            }
+            .onSuccess { gatt = it }
+            .onFailure { error ->
+                update {
+                    it.copy(
+                        phase = HeartRateDiagnosticPhase.ERROR,
+                        diagnostic = "connect_failed:" + error.javaClass.simpleName,
+                    )
+                }
+            }
+    }
+
+    private val gattCallback =
+        object : BluetoothGattCallback() {
+            @SuppressLint("MissingPermission")
+            override fun onConnectionStateChange(
+                callbackGatt: BluetoothGatt,
+                status: Int,
+                newState: Int,
+            ) {
+                main.post {
+                    if (closed || callbackGatt !== gatt) return@post
+                    if (status == BluetoothGatt.GATT_SUCCESS &&
+                        newState == BluetoothProfile.STATE_CONNECTED
+                    ) {
+                        update {
+                            it.copy(
+                                phase = HeartRateDiagnosticPhase.DISCOVERING,
+                                diagnostic = "connected",
+                            )
+                        }
+                        if (!callbackGatt.discoverServices()) {
+                            update {
+                                it.copy(
+                                    phase = HeartRateDiagnosticPhase.ERROR,
+                                    diagnostic = "discover_start_failed",
+                                )
+                            }
+                        }
+                    } else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
+                        update {
+                            it.copy(
+                                phase = HeartRateDiagnosticPhase.DISCONNECTED,
+                                diagnostic = "disconnected:" + status,
+                            )
+                        }
+                        closeGatt()
+                    } else if (status != BluetoothGatt.GATT_SUCCESS) {
+                        update {
+                            it.copy(
+                                phase = HeartRateDiagnosticPhase.ERROR,
+                                diagnostic = "gatt_status:" + status,
+                            )
+                        }
+                        closeGatt()
+                    }
+                }
+            }
+
+            @SuppressLint("MissingPermission")
+            override fun onServicesDiscovered(callbackGatt: BluetoothGatt, status: Int) {
+                main.post {
+                    if (closed || callbackGatt !== gatt) return@post
+                    if (status != BluetoothGatt.GATT_SUCCESS) {
+                        update {
+                            it.copy(
+                                phase = HeartRateDiagnosticPhase.ERROR,
+                                diagnostic = "service_discovery:" + status,
+                            )
+                        }
+                        return@post
+                    }
+                    val service = callbackGatt.getService(HEART_RATE_SERVICE_UUID)
+                    val measurement = service?.getCharacteristic(HEART_RATE_MEASUREMENT_UUID)
+                    val battery = callbackGatt.getService(BATTERY_SERVICE_UUID) != null
+                    update {
+                        it.copy(
+                            serviceFound = service != null,
+                            measurementFound = measurement != null,
+                            batteryServiceFound = battery,
+                        )
+                    }
+                    if (measurement == null) {
+                        update {
+                            it.copy(
+                                phase = HeartRateDiagnosticPhase.ERROR,
+                                diagnostic = "heart_rate_measurement_missing",
+                            )
+                        }
+                        return@post
+                    }
+                    subscribe(callbackGatt, measurement)
+                }
+            }
+
+            override fun onDescriptorWrite(
+                callbackGatt: BluetoothGatt,
+                descriptor: BluetoothGattDescriptor,
+                status: Int,
+            ) {
+                if (descriptor.uuid != CLIENT_CHARACTERISTIC_CONFIG_UUID) return
+                update {
+                    if (status == BluetoothGatt.GATT_SUCCESS) {
+                        it.copy(
+                            phase = HeartRateDiagnosticPhase.RECEIVING,
+                            diagnostic = "notifications_enabled",
+                        )
+                    } else {
+                        it.copy(
+                            phase = HeartRateDiagnosticPhase.ERROR,
+                            diagnostic = "descriptor_write:" + status,
+                        )
+                    }
+                }
+            }
+
+            @Deprecated("Deprecated by Android API 33 callback with explicit value")
+            override fun onCharacteristicChanged(
+                callbackGatt: BluetoothGatt,
+                characteristic: BluetoothGattCharacteristic,
+            ) {
+                @Suppress("DEPRECATION")
+                val value = characteristic.value ?: return
+                handleMeasurement(characteristic.uuid, value)
+            }
+
+            override fun onCharacteristicChanged(
+                callbackGatt: BluetoothGatt,
+                characteristic: BluetoothGattCharacteristic,
+                value: ByteArray,
+            ) {
+                handleMeasurement(characteristic.uuid, value)
+            }
+        }
+
+    @SuppressLint("MissingPermission")
+    private fun subscribe(
+        callbackGatt: BluetoothGatt,
+        measurement: BluetoothGattCharacteristic,
+    ) {
+        if (!callbackGatt.setCharacteristicNotification(measurement, true)) {
+            update {
+                it.copy(
+                    phase = HeartRateDiagnosticPhase.ERROR,
+                    diagnostic = "notification_enable_failed",
+                )
+            }
+            return
+        }
+        val descriptor = measurement.getDescriptor(CLIENT_CHARACTERISTIC_CONFIG_UUID)
+        if (descriptor == null) {
+            update {
+                it.copy(
+                    phase = HeartRateDiagnosticPhase.ERROR,
+                    diagnostic = "ccc_descriptor_missing",
+                )
+            }
+            return
+        }
+        update {
+            it.copy(
+                phase = HeartRateDiagnosticPhase.SUBSCRIBING,
+                diagnostic = "enabling_notifications",
+            )
+        }
+        val started =
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+                callbackGatt.writeDescriptor(
+                    descriptor,
+                    BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE,
+                ) == BluetoothStatusCodes.SUCCESS
+            } else {
+                @Suppress("DEPRECATION")
+                run {
+                    descriptor.value = BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE
+                    callbackGatt.writeDescriptor(descriptor)
+                }
+            }
+        if (!started) {
+            update {
+                it.copy(
+                    phase = HeartRateDiagnosticPhase.ERROR,
+                    diagnostic = "descriptor_write_start_failed",
+                )
+            }
+        }
+    }
+
+    private fun handleMeasurement(uuid: UUID, value: ByteArray) {
+        if (uuid != HEART_RATE_MEASUREMENT_UUID) return
+        when (val parsed = HeartRateMeasurementParser.parse(value)) {
+            is HeartRateMeasurementParseResult.Invalid ->
+                update {
+                    it.copy(
+                        phase = HeartRateDiagnosticPhase.ERROR,
+                        diagnostic = "measurement:" + parsed.reason,
+                    )
+                }
+            is HeartRateMeasurementParseResult.Parsed ->
+                update {
+                    it.copy(
+                        phase = HeartRateDiagnosticPhase.RECEIVING,
+                        notificationCount = it.notificationCount + 1,
+                        latestMeasurement = parsed.measurement,
+                        diagnostic = "measurement",
+                    )
+                }
+        }
+    }
+
+    @SuppressLint("MissingPermission")
+    fun stopScan() {
+        val callback = scannerCallback ?: return
+        scanStop?.let(main::removeCallbacks)
+        scanStop = null
+        runCatching { adapter?.bluetoothLeScanner?.stopScan(callback) }
+        scannerCallback = null
+    }
+
+    @SuppressLint("MissingPermission")
+    private fun closeGatt() {
+        val current = gatt
+        gatt = null
+        runCatching { current?.disconnect() }
+        runCatching { current?.close() }
+    }
+
+    override fun close() {
+        if (closed) return
+        stopScan()
+        closeGatt()
+        closed = true
+    }
+
+    private companion object {
+        const val SCAN_DURATION_MS = 10_000L
+    }
+}

android/app/src/main/java/com/labfytools/trainlog/data/HeartRateMeasurementParser.kt

@@ -0,0 +1,103 @@
+/*
+ * Bluetooth Heart Rate Measurement parser.
+ *
+ * This file deliberately has no Android Bluetooth dependency so protocol
+ * decoding can be exhaustively unit-tested independently of GATT transport.
+ */
+package com.labfytools.trainlog.data
+
+internal data class ParsedHeartRateMeasurement(
+    val bpm: Int,
+    val sensorContactDetected: Boolean?,
+    val energyExpended: Int?,
+    /** Raw Bluetooth Heart Rate Service units: 1/1024 second. */
+    val rrIntervals1024: List<Int>,
+)
+
+internal sealed interface HeartRateMeasurementParseResult {
+    data class Parsed(val measurement: ParsedHeartRateMeasurement) :
+        HeartRateMeasurementParseResult
+    data class Invalid(val reason: String) : HeartRateMeasurementParseResult
+}
+
+internal object HeartRateMeasurementParser {
+    private const val FLAG_HEART_RATE_16_BIT = 1 shl 0
+    private const val FLAG_CONTACT_DETECTED = 1 shl 1
+    private const val FLAG_CONTACT_SUPPORTED = 1 shl 2
+    private const val FLAG_ENERGY_PRESENT = 1 shl 3
+    private const val FLAG_RR_PRESENT = 1 shl 4
+    private const val KNOWN_FLAGS =
+        FLAG_HEART_RATE_16_BIT or FLAG_CONTACT_DETECTED or FLAG_CONTACT_SUPPORTED or
+            FLAG_ENERGY_PRESENT or FLAG_RR_PRESENT
+
+    fun parse(payload: ByteArray): HeartRateMeasurementParseResult {
+        if (payload.isEmpty()) return HeartRateMeasurementParseResult.Invalid("missing flags")
+        val flags = payload[0].toInt() and 0xff
+        if ((flags and KNOWN_FLAGS.inv()) != 0) {
+            return HeartRateMeasurementParseResult.Invalid("reserved flags are set")
+        }
+
+        var offset = 1
+        fun uint8(): Int? =
+            payload.getOrNull(offset)?.let {
+                offset += 1
+                it.toInt() and 0xff
+            }
+        fun uint16(): Int? {
+            if (offset + 2 > payload.size) return null
+            val value =
+                (payload[offset].toInt() and 0xff) or
+                    ((payload[offset + 1].toInt() and 0xff) shl 8)
+            offset += 2
+            return value
+        }
+
+        val bpm =
+            if ((flags and FLAG_HEART_RATE_16_BIT) != 0) {
+                uint16() ?: return HeartRateMeasurementParseResult.Invalid("truncated 16-bit BPM")
+            } else {
+                uint8() ?: return HeartRateMeasurementParseResult.Invalid("missing BPM")
+            }
+
+        val contact =
+            if ((flags and FLAG_CONTACT_SUPPORTED) == 0) {
+                null
+            } else {
+                (flags and FLAG_CONTACT_DETECTED) != 0
+            }
+
+        val energy =
+            if ((flags and FLAG_ENERGY_PRESENT) != 0) {
+                uint16()
+                    ?: return HeartRateMeasurementParseResult.Invalid(
+                        "truncated energy-expended value",
+                    )
+            } else {
+                null
+            }
+
+        val rr = mutableListOf<Int>()
+        if ((flags and FLAG_RR_PRESENT) != 0) {
+            if (offset == payload.size) {
+                return HeartRateMeasurementParseResult.Invalid("RR flag has no interval")
+            }
+            if ((payload.size - offset) % 2 != 0) {
+                return HeartRateMeasurementParseResult.Invalid("truncated RR interval")
+            }
+            while (offset < payload.size) {
+                rr += checkNotNull(uint16())
+            }
+        } else if (offset != payload.size) {
+            return HeartRateMeasurementParseResult.Invalid("unexpected trailing bytes")
+        }
+
+        return HeartRateMeasurementParseResult.Parsed(
+            ParsedHeartRateMeasurement(
+                bpm = bpm,
+                sensorContactDetected = contact,
+                energyExpended = energy,
+                rrIntervals1024 = rr,
+            ),
+        )
+    }
+}

android/app/src/main/java/com/labfytools/trainlog/ui/AndroidAppShell.kt

@@ -77,6 +77,7 @@ fun AndroidAppShell(
         AppRoute.BodyMeasurements -> R.string.route_body_measurements; AppRoute.LatestMaxima -> R.string.route_latest_maxima
         AppRoute.SleepDiary -> R.string.nav_sleep
         AppRoute.Sync -> R.string.nav_sync; AppRoute.Settings -> R.string.nav_settings
+        AppRoute.HeartRateDiagnostics -> R.string.route_heart_rate_diagnostics
     })
     val drawerState = rememberDrawerState(DrawerValue.Closed)
     val scope = rememberCoroutineScope()

android/app/src/main/java/com/labfytools/trainlog/ui/AppNavigation.kt

@@ -39,6 +39,7 @@ sealed interface AppRoute {
     data object LatestMaxima : AppRoute { override val section = AppSection.EXERCISES }
     data object Sync : AppRoute { override val section = AppSection.SYNC }
     data object Settings : AppRoute { override val section = AppSection.SETTINGS }
+    data object HeartRateDiagnostics : AppRoute { override val section = AppSection.SETTINGS }
 }
 
 fun AppSection.rootRoute(): AppRoute = when (this) {

android/app/src/main/java/com/labfytools/trainlog/ui/HeartRateDiagnosticsScreen.kt

@@ -0,0 +1,180 @@
+package com.labfytools.trainlog.ui
+
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.unit.dp
+import com.labfytools.trainlog.R
+import com.labfytools.trainlog.data.HeartRateBleDiagnostics
+import com.labfytools.trainlog.data.HeartRateDiagnosticPhase
+import com.labfytools.trainlog.data.HeartRateDiagnosticSnapshot
+import com.labfytools.trainlog.data.hasHeartRateBleRuntimePermissions
+import com.labfytools.trainlog.data.heartRateBleRuntimePermissions
+import com.labfytools.trainlog.ui.theme.LocalTrainlogColors
+
+@Composable
+fun HeartRateDiagnosticsScreen() {
+    val context = LocalContext.current
+    val strings = localizedContext()
+    val colors = LocalTrainlogColors.current
+    var snapshot by remember { mutableStateOf(HeartRateDiagnosticSnapshot()) }
+    var pendingExpandedScan by remember { mutableStateOf(false) }
+    var permissionDenied by remember { mutableStateOf(false) }
+    val diagnostics =
+        remember(context) {
+            HeartRateBleDiagnostics(context) { next -> snapshot = next }
+        }
+
+    DisposableEffect(diagnostics) {
+        onDispose { diagnostics.close() }
+    }
+
+    val permissionLauncher =
+        rememberLauncherForActivityResult(
+            ActivityResultContracts.RequestMultiplePermissions(),
+        ) { results ->
+            if (heartRateBleRuntimePermissions().all { results[it] == true }) {
+                permissionDenied = false
+                diagnostics.startScan(pendingExpandedScan)
+            } else {
+                permissionDenied = true
+            }
+        }
+
+    fun scan(expanded: Boolean) {
+        pendingExpandedScan = expanded
+        if (hasHeartRateBleRuntimePermissions(context)) {
+            permissionDenied = false
+            diagnostics.startScan(expanded)
+        } else {
+            permissionLauncher.launch(heartRateBleRuntimePermissions())
+        }
+    }
+
+    fun phaseLabel(): String =
+        strings.getString(
+            when (snapshot.phase) {
+                HeartRateDiagnosticPhase.IDLE -> R.string.hr_diag_idle
+                HeartRateDiagnosticPhase.SCANNING -> R.string.hr_diag_scanning
+                HeartRateDiagnosticPhase.CONNECTING -> R.string.hr_diag_connecting
+                HeartRateDiagnosticPhase.DISCOVERING -> R.string.hr_diag_discovering
+                HeartRateDiagnosticPhase.SUBSCRIBING -> R.string.hr_diag_subscribing
+                HeartRateDiagnosticPhase.RECEIVING -> R.string.hr_diag_receiving
+                HeartRateDiagnosticPhase.DISCONNECTED -> R.string.hr_diag_disconnected
+                HeartRateDiagnosticPhase.ERROR -> R.string.hr_diag_error
+            },
+        )
+
+    TrainlogScreen(strings.getString(R.string.route_heart_rate_diagnostics)) {
+        TrainlogFrame(strings.getString(R.string.hr_diag_status)) {
+            TrainlogInfo(
+                phaseLabel(),
+                when (snapshot.phase) {
+                    HeartRateDiagnosticPhase.RECEIVING -> colors.success
+                    HeartRateDiagnosticPhase.ERROR -> colors.error
+                    HeartRateDiagnosticPhase.CONNECTING,
+                    HeartRateDiagnosticPhase.DISCOVERING,
+                    HeartRateDiagnosticPhase.SUBSCRIBING,
+                    HeartRateDiagnosticPhase.SCANNING -> colors.warning
+                    else -> colors.muted
+                },
+            )
+            if (permissionDenied) {
+                TrainlogInfo(strings.getString(R.string.hr_diag_permission_denied), colors.error)
+            }
+            snapshot.diagnostic?.let {
+                TrainlogInfo(strings.getString(R.string.hr_diag_technical, it), colors.muted)
+            }
+            TrainlogInfo(
+                strings.getString(
+                    R.string.hr_diag_services,
+                    if (snapshot.serviceFound) strings.getString(R.string.yes) else strings.getString(R.string.no),
+                    if (snapshot.measurementFound) strings.getString(R.string.yes) else strings.getString(R.string.no),
+                    if (snapshot.batteryServiceFound) strings.getString(R.string.yes) else strings.getString(R.string.no),
+                ),
+            )
+            snapshot.latestMeasurement?.let { measurement ->
+                TrainlogInfo(
+                    strings.getString(R.string.hr_diag_bpm, measurement.bpm),
+                    colors.success,
+                )
+                TrainlogInfo(
+                    strings.getString(
+                        R.string.hr_diag_measurement_meta,
+                        measurement.rrIntervals1024.size,
+                        measurement.sensorContactDetected?.let { if (it) strings.getString(R.string.yes) else strings.getString(R.string.no) } ?: "—",
+                        measurement.energyExpended?.toString() ?: "—",
+                    ),
+                    colors.muted,
+                )
+            }
+            TrainlogInfo(
+                strings.getString(R.string.hr_diag_notifications, snapshot.notificationCount),
+                colors.muted,
+            )
+        }
+
+        TrainlogFrame(strings.getString(R.string.hr_diag_scan_section)) {
+            Row(
+                Modifier.fillMaxWidth(),
+                horizontalArrangement = Arrangement.spacedBy(8.dp),
+            ) {
+                TrainlogButton(
+                    strings.getString(R.string.hr_diag_scan),
+                    { scan(false) },
+                    Modifier.weight(1f),
+                    enabled = snapshot.phase != HeartRateDiagnosticPhase.SCANNING,
+                )
+                TrainlogButton(
+                    strings.getString(R.string.hr_diag_scan_all),
+                    { scan(true) },
+                    Modifier.weight(1f),
+                    enabled = snapshot.phase != HeartRateDiagnosticPhase.SCANNING,
+                )
+            }
+            TrainlogInfo(strings.getString(R.string.hr_diag_scan_description), colors.muted)
+        }
+
+        TrainlogFrame(
+            strings.getString(R.string.hr_diag_devices),
+            active = snapshot.devices.isNotEmpty(),
+        ) {
+            if (snapshot.devices.isEmpty()) {
+                TrainlogInfo(strings.getString(R.string.hr_diag_no_devices), colors.muted)
+            }
+            snapshot.devices.forEach { device ->
+                val title =
+                    device.name?.takeIf { it.isNotBlank() }
+                        ?: strings.getString(R.string.hr_diag_unnamed_device)
+                val advertised =
+                    strings.getString(
+                        if (device.advertisesHeartRate) {
+                            R.string.hr_diag_hrs_advertised
+                        } else {
+                            R.string.hr_diag_hrs_not_advertised
+                        },
+                    )
+                TrainlogAction(
+                    title,
+                    strings.getString(
+                        R.string.hr_diag_device_description,
+                        device.address,
+                        device.rssi,
+                        advertised,
+                    ),
+                    { diagnostics.connect(device.address) },
+                )
+            }
+        }
+    }
+}

android/app/src/main/java/com/labfytools/trainlog/ui/SectionScreens.kt

@@ -472,7 +472,12 @@ private fun catalogCountsText(context: android.content.Context, imported: Int, r
     ).joinToString(", ")
 
 @Composable
-fun SettingsScreen(repository: TrainlogRepository, inbox: SyncCatalogInbox, onCatalogChanged: () -> Unit) {
+fun SettingsScreen(
+    repository: TrainlogRepository,
+    inbox: SyncCatalogInbox,
+    onHeartRateDiagnostics: () -> Unit,
+    onCatalogChanged: () -> Unit,
+) {
     val colors = LocalTrainlogColors.current
     val context = LocalContext.current
     val language = LocalLanguagePresentation.current
@@ -533,6 +538,13 @@ fun SettingsScreen(repository: TrainlogRepository, inbox: SyncCatalogInbox, onCa
                 )
             }
         }
+        TrainlogFrame(strings.getString(R.string.settings_cardio_section)) {
+            TrainlogAction(
+                strings.getString(R.string.settings_cardio_diagnostics),
+                strings.getString(R.string.settings_cardio_diagnostics_description),
+                onHeartRateDiagnostics,
+            )
+        }
         TrainlogFrame(strings.getString(R.string.settings_exchange_folder)) {
             TrainlogInfo(strings.getString(if (authorized) R.string.settings_folder_granted else R.string.settings_folder_required), if (authorized) colors.success else colors.warning)
             TrainlogAction(strings.getString(if (authorized) R.string.settings_open_access else R.string.settings_authorize), strings.getString(R.string.settings_authorize_description), { launcher.launch(directStoragePermissionIntent(context)) })

android/app/src/main/java/com/labfytools/trainlog/ui/TrainlogApp.kt

@@ -195,7 +195,8 @@ fun TrainlogApp(repository: TrainlogRepository, exporter: SyncExporter, inbox: S
             AppRoute.SleepDiary -> SleepDiaryScreen(repository)
             AppRoute.LatestMaxima -> LatestMaximaScreen(repository)
             AppRoute.Sync -> SyncScreen(repository, inbox, exporter, requestOutbox, { exportSnapshot(); catalogRevision++ }, { back() })
-            AppRoute.Settings -> SettingsScreen(repository, inbox) { exportSnapshot(); catalogRevision++ }
+            AppRoute.Settings -> SettingsScreen(repository, inbox, { open(AppRoute.HeartRateDiagnostics) }) { exportSnapshot(); catalogRevision++ }
+            AppRoute.HeartRateDiagnostics -> HeartRateDiagnosticsScreen()
         }}
     }
 

android/app/src/main/res/values-en/strings.xml

@@ -480,4 +480,35 @@
     <string name="sleep_unit">Unit</string>
     <string name="sleep_deactivate">Deactivate</string>
     <string name="sleep_edit">Edit</string>
+    <string name="yes">Yes</string>
+    <string name="no">No</string>
+    <string name="route_heart_rate_diagnostics">BLE heart-rate diagnostics</string>
+    <string name="settings_cardio_section">Cardio</string>
+    <string name="settings_cardio_diagnostics">Heart-rate sensor diagnostics</string>
+    <string name="settings_cardio_diagnostics_description">Find and verify a Bluetooth Heart Rate Service sensor.</string>
+    <string name="hr_diag_status">Sensor status</string>
+    <string name="hr_diag_idle">Ready</string>
+    <string name="hr_diag_scanning">Scanning…</string>
+    <string name="hr_diag_connecting">Connecting…</string>
+    <string name="hr_diag_discovering">Discovering services…</string>
+    <string name="hr_diag_subscribing">Enabling measurements…</string>
+    <string name="hr_diag_receiving">Measurements received</string>
+    <string name="hr_diag_disconnected">Disconnected</string>
+    <string name="hr_diag_error">BLE error</string>
+    <string name="hr_diag_permission_denied">Bluetooth permission denied.</string>
+    <string name="hr_diag_technical">Diagnostic: %1$s</string>
+    <string name="hr_diag_services">Heart Rate Service: %1$s · measurement: %2$s · battery: %3$s</string>
+    <string name="hr_diag_bpm">%1$d BPM</string>
+    <string name="hr_diag_measurement_meta">%1$d RR · contact %2$s · energy %3$s</string>
+    <string name="hr_diag_notifications">Notifications received: %1$d</string>
+    <string name="hr_diag_scan_section">BLE scan</string>
+    <string name="hr_diag_scan">Find heart-rate</string>
+    <string name="hr_diag_scan_all">Expanded scan</string>
+    <string name="hr_diag_scan_description">Heart-rate scan lasts at most 10 seconds. Expanded scan is for sensors that do not advertise their service in BLE advertisements.</string>
+    <string name="hr_diag_devices">BLE devices</string>
+    <string name="hr_diag_no_devices">No device found yet.</string>
+    <string name="hr_diag_unnamed_device">Unnamed device</string>
+    <string name="hr_diag_hrs_advertised">Heart Rate advertised</string>
+    <string name="hr_diag_hrs_not_advertised">Heart Rate not advertised</string>
+    <string name="hr_diag_device_description">%1$s · %2$d dBm · %3$s</string>
 </resources>

android/app/src/main/res/values/strings.xml

@@ -490,4 +490,35 @@
     <string name="sleep_unit">Unité</string>
     <string name="sleep_deactivate">Désactiver</string>
     <string name="sleep_edit">Modifier</string>
+    <string name="yes">Oui</string>
+    <string name="no">Non</string>
+    <string name="route_heart_rate_diagnostics">Diagnostic cardio BLE</string>
+    <string name="settings_cardio_section">Cardio</string>
+    <string name="settings_cardio_diagnostics">Diagnostic du capteur cardio</string>
+    <string name="settings_cardio_diagnostics_description">Rechercher et vérifier un capteur Bluetooth Heart Rate Service.</string>
+    <string name="hr_diag_status">État du capteur</string>
+    <string name="hr_diag_idle">Prêt</string>
+    <string name="hr_diag_scanning">Recherche en cours…</string>
+    <string name="hr_diag_connecting">Connexion…</string>
+    <string name="hr_diag_discovering">Découverte des services…</string>
+    <string name="hr_diag_subscribing">Activation des mesures…</string>
+    <string name="hr_diag_receiving">Mesures reçues</string>
+    <string name="hr_diag_disconnected">Déconnecté</string>
+    <string name="hr_diag_error">Erreur BLE</string>
+    <string name="hr_diag_permission_denied">Autorisation Bluetooth refusée.</string>
+    <string name="hr_diag_technical">Diagnostic : %1$s</string>
+    <string name="hr_diag_services">Heart Rate Service : %1$s · mesure : %2$s · batterie : %3$s</string>
+    <string name="hr_diag_bpm">%1$d BPM</string>
+    <string name="hr_diag_measurement_meta">%1$d RR · contact %2$s · énergie %3$s</string>
+    <string name="hr_diag_notifications">Notifications reçues : %1$d</string>
+    <string name="hr_diag_scan_section">Recherche BLE</string>
+    <string name="hr_diag_scan">Rechercher cardio</string>
+    <string name="hr_diag_scan_all">Recherche élargie</string>
+    <string name="hr_diag_scan_description">La recherche cardio dure au maximum 10 secondes. La recherche élargie sert aux capteurs qui n’annoncent pas leur service dans la publicité BLE.</string>
+    <string name="hr_diag_devices">Périphériques BLE</string>
+    <string name="hr_diag_no_devices">Aucun périphérique trouvé pour l’instant.</string>
+    <string name="hr_diag_unnamed_device">Périphérique sans nom</string>
+    <string name="hr_diag_hrs_advertised">Heart Rate annoncé</string>
+    <string name="hr_diag_hrs_not_advertised">Heart Rate non annoncé</string>
+    <string name="hr_diag_device_description">%1$s · %2$d dBm · %3$s</string>
 </resources>

android/app/src/test/java/com/labfytools/trainlog/data/HeartRateMeasurementParserTest.kt

@@ -0,0 +1,95 @@
+package com.labfytools.trainlog.data
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNull
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class HeartRateMeasurementParserTest {
+    private fun parsed(vararg bytes: Int): ParsedHeartRateMeasurement {
+        val result =
+            HeartRateMeasurementParser.parse(
+                ByteArray(bytes.size) { index -> bytes[index].toByte() },
+            )
+        return (result as HeartRateMeasurementParseResult.Parsed).measurement
+    }
+
+    private fun invalid(vararg bytes: Int): HeartRateMeasurementParseResult.Invalid =
+        HeartRateMeasurementParser.parse(
+            ByteArray(bytes.size) { index -> bytes[index].toByte() },
+        ) as HeartRateMeasurementParseResult.Invalid
+
+    @Test
+    fun parsesEightBitBpm() {
+        val value = parsed(0x00, 72)
+        assertEquals(72, value.bpm)
+        assertNull(value.sensorContactDetected)
+        assertNull(value.energyExpended)
+        assertTrue(value.rrIntervals1024.isEmpty())
+    }
+
+    @Test
+    fun parsesSixteenBitBpmLittleEndian() {
+        assertEquals(300, parsed(0x01, 0x2c, 0x01).bpm)
+        assertEquals(65535, parsed(0x01, 0xff, 0xff).bpm)
+    }
+
+    @Test
+    fun contactIsNullableAndOnlyMeaningfulWhenSupported() {
+        assertNull(parsed(0x02, 80).sensorContactDetected)
+        assertEquals(false, parsed(0x04, 80).sensorContactDetected)
+        assertEquals(true, parsed(0x06, 80).sensorContactDetected)
+    }
+
+    @Test
+    fun parsesEnergyExpended() {
+        val value = parsed(0x08, 90, 0x34, 0x12)
+        assertEquals(0x1234, value.energyExpended)
+    }
+
+    @Test
+    fun parsesOneAndMultipleRawRrIntervals() {
+        assertEquals(listOf(1024), parsed(0x10, 60, 0x00, 0x04).rrIntervals1024)
+        assertEquals(
+            listOf(1024, 1000, 65535),
+            parsed(0x10, 60, 0x00, 0x04, 0xe8, 0x03, 0xff, 0xff).rrIntervals1024,
+        )
+    }
+
+    @Test
+    fun parsesCombinedKnownFlagsInWireOrder() {
+        val value =
+            parsed(
+                0x1f,
+                0x96,
+                0x00,
+                0x07,
+                0x00,
+                0xf0,
+                0x03,
+                0x00,
+                0x04,
+            )
+        assertEquals(150, value.bpm)
+        assertEquals(true, value.sensorContactDetected)
+        assertEquals(7, value.energyExpended)
+        assertEquals(listOf(1008, 1024), value.rrIntervals1024)
+    }
+
+    @Test
+    fun rejectsTruncatedAndIncoherentPayloads() {
+        assertEquals("missing flags", invalid().reason)
+        assertEquals("truncated 16-bit BPM", invalid(0x01, 0x2c).reason)
+        assertEquals("truncated energy-expended value", invalid(0x08, 70, 0x01).reason)
+        assertEquals("RR flag has no interval", invalid(0x10, 70).reason)
+        assertEquals("truncated RR interval", invalid(0x10, 70, 0x01).reason)
+        assertEquals("unexpected trailing bytes", invalid(0x00, 70, 0x01).reason)
+        assertEquals("reserved flags are set", invalid(0x20, 70).reason)
+    }
+
+    @Test
+    fun preservesBoundaryBpmValues() {
+        assertEquals(0, parsed(0x00, 0).bpm)
+        assertEquals(255, parsed(0x00, 255).bpm)
+    }
+}

docs/current_state.md

@@ -148,7 +148,8 @@ parallel implementation of its rules.
 | Local Web | `TRAINLOG_WEB_V1=CONTRACT_FROZEN / IMPLEMENTATION_STARTED` |
 | Web Exercises V1 | `TRAINLOG_WEB_EXERCISES_V1=PASS` |
 | Cardio persistence/sync | `TRAINLOG_CARDIO_PERSISTENCE_SYNC_V1=PASS`: Android v27 + desktop v30, strict optional `trainlog-heart-rate` V1 Android→desktop companion, generation relation and correlated ACK |
-| Current operational cursor | `TRAINLOG_CARDIO_BLE_DIAGNOSTICS_V1`: standard Heart Rate Service parser, Android BLE discovery and real-sensor characterization |
+| Cardio BLE diagnostics | `TRAINLOG_CARDIO_BLE_DIAGNOSTICS_V1=SOFTWARE_PASS / HARDWARE_VALIDATION_PENDING`: strict `0x2A37` parser, bounded HRS/expanded BLE scan, GATT service discovery and notification subscription are installed on Android 0.1.5 vc38; filtered real-device scan observed no advertising HRS device on 2026-09-23 |
+| Current operational cursor | `TRAINLOG_CARDIO_BLE_HARDWARE_VALIDATION_V1`: identify the real armband, confirm `0x180D/0x2A37`, notification cadence and optional RR/contact/energy fields before persistent acquisition |
 | Complete synchronization gap contract | Frozen dependency contract; operational USB/Drive slices required by v0.1.2 are delivered |
 | Isolated synchronization test environment | `TRAINLOG_SYNC_TEST_ENV_V1=PASS/FROZEN` |
 | Synchronization characterization | `TRAINLOG_SYNC_CHARACTERIZATION_V1=PASS/FROZEN` |

docs/roadmap.md

@@ -69,7 +69,7 @@ sensor. Heart-rate ingestion must not reuse or overload the frozen Trainlog
 Bluetooth synchronization transport contract.
 
 ```text
-CURRENT_OPERATIONAL_CURSOR=TRAINLOG_CARDIO_BLE_DIAGNOSTICS_V1
+CURRENT_OPERATIONAL_CURSOR=TRAINLOG_CARDIO_BLE_HARDWARE_VALIDATION_V1
 ```
 
 The focused `TRAINLOG_SYNC_CAUSAL_DELETE_V1_CLOSEOUT` is complete before this

docs/tests.md

@@ -1670,3 +1670,30 @@ The 2026-09-23 closeout passes the complete native Meson inventory:
 **258 tests: 253 passed, five skipped, zero failures/errors**. The five skips
 remain optional historical/external fixture gates and are not Cardio V1
 failures.
+
+## Cardio BLE diagnostics V1 validation
+
+`TRAINLOG_CARDIO_BLE_DIAGNOSTICS_V1=SOFTWARE_PASS / HARDWARE_VALIDATION_PENDING`
+keeps BLE protocol parsing separate from Android GATT transport. Unit coverage
+exercises 8-bit and 16-bit BPM, nullable sensor-contact semantics, cumulative
+energy, one/multiple raw RR intervals, combined flags, boundary BPM values,
+reserved flags, missing fields, truncated RR/energy values and unexpected
+trailing bytes.
+
+The Android diagnostic uses a 10-second Heart Rate Service-filtered scan with
+an explicit expanded BLE fallback, then discovers `0x180D`, locates `0x2A37`,
+checks optional Battery Service and enables the CCC notification descriptor.
+It is screen-scoped and does not implement the later persistent foreground
+acquisition owner.
+
+On 2026-09-23 the diagnostic APK was installed non-destructively on the
+authorized SM_G990B as Trainlog 0.1.5 versionCode 38 using the same Android
+debug signing certificate as the existing private installation. Application
+startup completed without SQLite/crash errors and the diagnostic route opened.
+The first real 10-second HRS-filtered scan completed cleanly but found no
+device advertising Heart Rate Service. Real armband identification, GATT HRS
+confirmation and notification-field characterization therefore remain
+`HARDWARE_VALIDATION_PENDING` and are not represented as PASS.
+
+The complete Android JVM inventory after this tranche reports **266 tests:
+261 passed, five skipped, zero failures/errors**, and `assembleDebug` succeeds.