android: move ATT code to viewmodel from screens and enable notifications

android/app/src/main/java/me/kavishdevar/librepods/MainActivity.kt

@@ -466,7 +466,7 @@ fun Main() {
                         OpenSourceLicensesScreen(navController)
                     }
                     composable("update_hearing_test") {
-                        if (airPodsViewModel != null) UpdateHearingTestScreen()
+                        if (airPodsViewModel != null) UpdateHearingTestScreen(airPodsViewModel)
                     }
                     composable("version_info") {
                         if (airPodsViewModel != null) VersionScreen(airPodsViewModel)

android/app/src/main/java/me/kavishdevar/librepods/bluetooth/ATTManager.kt

@@ -16,247 +16,196 @@
     along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
- /* This is a very basic ATT (Attribute Protocol) implementation. I have only implemented
-  * what is necessary for LibrePods to function, i.e. reading and writing characteristics,
-  * and receiving notifications. It is not a complete implementation of the ATT protocol.
- */
-
 package me.kavishdevar.librepods.bluetooth
 
-import android.annotation.SuppressLint
-import android.bluetooth.BluetoothAdapter
-import android.bluetooth.BluetoothDevice
-import android.bluetooth.BluetoothSocket
-import android.os.ParcelUuid
 import android.util.Log
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.Job
-import kotlinx.coroutines.launch
-import java.io.InputStream
-import java.io.OutputStream
+import java.util.concurrent.ConcurrentHashMap
 import java.util.concurrent.LinkedBlockingQueue
 import java.util.concurrent.TimeUnit
+import java.util.concurrent.atomic.AtomicBoolean
+
+private const val TAG = "ATTManager"
 
 enum class ATTHandles(val value: Int) {
     TRANSPARENCY(0x18),
     LOUD_SOUND_REDUCTION(0x1B),
-    HEARING_AID(0x2A),
+    HEARING_AID(0x2A)
 }
 
 enum class ATTCCCDHandles(val value: Int) {
     TRANSPARENCY(ATTHandles.TRANSPARENCY.value + 1),
-    LOUD_SOUND_REDUCTION(ATTHandles.LOUD_SOUND_REDUCTION.value + 1),
-    HEARING_AID(ATTHandles.HEARING_AID.value + 1),
+//    LOUD_SOUND_REDUCTION(ATTHandles.LOUD_SOUND_REDUCTION.value + 1), // doesn't work
+    HEARING_AID(ATTHandles.HEARING_AID.value + 1)
 }
 
-class ATTManager(private val adapter: BluetoothAdapter, private val device: BluetoothDevice) {
-    companion object {
-        private const val OPCODE_READ_REQUEST: Byte = 0x0A
-        private const val OPCODE_WRITE_REQUEST: Byte = 0x12
-        private const val OPCODE_HANDLE_VALUE_NTF: Byte = 0x1B
+class ATTManagerv2 {
+    val characteristicList = mutableMapOf<ATTHandles, ByteArray>()
+
+    private val responseQueues = ConcurrentHashMap<Byte, LinkedBlockingQueue<ByteArray>>()
+
+    private val readerRunning = AtomicBoolean(false)
+    private var readerThread: Thread? = null
+
+    private var onNotificationReceived: ((handle: Byte, value: ByteArray) -> Unit)? = null
+
+    fun startReader() {
+        if (readerRunning.getAndSet(true)) return
+
+        readerThread = Thread {
+            try {
+                runReaderLoop()
+            } catch (t: Throwable) {
+                Log.e(TAG, "reader thread crashed: ${t.message}", t)
+            } finally {
+                readerRunning.set(false)
+                Log.d(TAG, "reader thread stopped")
+            }
+        }.also { it.name = "ATT-Reader"; it.isDaemon = true; it.start() }
+        Log.d(TAG, "reader started")
     }
-    private val id = System.identityHashCode(this)
-    @Suppress("PrivatePropertyName")
-    private val TAG = "ATTManager[$id]"
-    var socket: BluetoothSocket? = null
-    private var input: InputStream? = null
-    private var output: OutputStream? = null
-    private val listeners = mutableMapOf<Int, MutableList<(ByteArray) -> Unit>>()
-    private var notificationJob: Job? = null
 
-    // queue for non-notification PDUs (responses to requests)
-    private val responses = LinkedBlockingQueue<ByteArray>()
+    fun stopReader() {
+        readerRunning.set(false)
+        readerThread?.interrupt()
+        readerThread = null
+    }
 
-    @SuppressLint("MissingPermission")
-    fun connect() {
-        val uuid = ParcelUuid.fromString("00000000-0000-0000-0000-000000000000")
+    fun setOnNotificationReceived(listener: ((handle: Byte, value: ByteArray) -> Unit)?) {
+        onNotificationReceived = listener
+    }
 
-        if (socket == null) {
-            Log.d(TAG, "Socket doesn't exist, creating")
-            try {
-                socket = createBluetoothSocket(adapter, device, uuid)
-            } catch (e: Exception) {
-                Log.w(TAG, "Failed to create socket")
-                e.printStackTrace()
+    fun enableNotification(handle: ATTCCCDHandles) {
+        writeCharacteristic(handle.value.toByte(), byteArrayOf(0x01))
+    }
+
+    fun getCharacteristic(handle: ATTHandles): ByteArray? {
+        val storedValue = characteristicList[handle]
+        return if (storedValue?.isNotEmpty() != true) {
+            readCharacteristic(handle)
+        } else storedValue
+    }
+
+    fun readCharacteristic(handle: ATTHandles, timeoutMillis: Long = 2000): ByteArray? {
+        val socket = BluetoothConnectionManager.getATTSocket() ?: return null
+        try {
+            val output = socket.outputStream
+            val pdu = byteArrayOf(0x0A, handle.value.toByte(), 0x00)
+            synchronized(output) {
+                output.write(pdu)
+                output.flush()
+            }
+            Log.d(TAG, "sending read request: ${pdu.joinToString(" ") { String.format("%02X", it) }}")
+
+            val resp = waitForResponse(0x0B, timeoutMillis) ?: run {
+                Log.e(TAG, "Timeout waiting for Read Response (0x0B) for handle ${handle.value}")
+                return null
+            }
+
+            Log.d(TAG, "read response: ${resp.joinToString(" ") { String.format("%02X", it) }}")
+            val value = resp.copyOfRange(1, resp.size)
+            characteristicList[handle] = value
+            return value
+        } catch (e: Exception) {
+            Log.e(TAG, "error reading characteristic: ${e.message}")
+            return null
+        }
+    }
+
+    fun writeCharacteristic(handle: ATTHandles, data: ByteArray, timeoutMillis: Long = 2000) {
+        characteristicList[handle] = data
+        writeCharacteristic(handle.value.toByte(), data, timeoutMillis)
+    }
+
+    fun writeCharacteristic(handle: Byte, data: ByteArray, timeoutMillis: Long = 2000) {
+        val socket = BluetoothConnectionManager.getATTSocket() ?: return
+        try {
+            val output = socket.outputStream
+            val pdu = byteArrayOf(0x12, handle, 0x00) + data // 0x00 for LE
+            synchronized(output) {
+                output.write(pdu)
+                output.flush()
+            }
+            Log.d(TAG, "sending write request: ${pdu.joinToString(" ") { String.format("%02X", it) }}")
+
+            val resp = waitForResponse(0x13, timeoutMillis) ?: run {
+                Log.e(TAG, "timeout waiting for response (0x13) for handle ${String.format("%02X", handle)}")
                 return
             }
-        }
-        if (socket?.isConnected != true) {
-            Log.d(TAG, "Connection to socket")
-            try {
-                socket!!.connect()
-            } catch (e: Exception) {
-                Log.w(TAG, "ATT socket failed to connect")
-                e.printStackTrace()
-                return
-            }
-        }
-        input = socket!!.inputStream
-        output = socket!!.outputStream
-        Log.d(TAG, "Connected to ATT")
 
-        notificationJob = CoroutineScope(Dispatchers.IO).launch {
-            while (socket?.isConnected == true) {
-                try {
-                    val pdu = readPDU()
-                    if (pdu.isNotEmpty() && pdu[0] == OPCODE_HANDLE_VALUE_NTF) {
-                        // notification -> dispatch to listeners
-                        val handle = (pdu[1].toInt() and 0xFF) or ((pdu[2].toInt() and 0xFF) shl 8)
-                        val value = pdu.copyOfRange(3, pdu.size)
-                        listeners[handle]?.forEach { listener ->
-                            try {
-                                listener(value)
-                                Log.d(TAG, "Dispatched notification for handle $handle to listener, with value ${value.joinToString(" ") { String.format("%02X", it) }}")
-                            } catch (e: Exception) {
-                                Log.w(TAG, "Error in listener for handle $handle: ${e.message}")
-                            }
+            Log.d(TAG, "write respose: ${resp.joinToString(" ") { String.format("%02X", it) }}")
+        } catch (e: Exception) {
+            Log.e(TAG, "error writing characteristic: ${e.message}")
+        }
+    }
+
+    fun disconnected() {
+        characteristicList.clear()
+        stopReader()
+        val socket = BluetoothConnectionManager.getATTSocket() ?: return
+        try {
+            socket.close()
+        } catch (e: Exception) {
+            Log.w(TAG, "error closing socket: ${e.message}")
+        }
+        Log.d(TAG, "ATT disconnected")
+    }
+
+    private fun runReaderLoop() {
+        val socket = BluetoothConnectionManager.getATTSocket() ?: run {
+            Log.w(TAG, "ATT socket not available. stopping reader")
+            readerRunning.set(false)
+            return
+        }
+
+        val input = socket.inputStream
+        val buffer = ByteArray(512)
+
+        while (readerRunning.get()) {
+            try {
+                val len = input.read(buffer)
+                if (len == -1) {
+                    Log.w(TAG, "ATT input stream ended")
+                    break
+                }
+                val data = buffer.copyOfRange(0, len)
+                if (data.isEmpty()) continue
+
+                val opcode = data[0]
+                Log.d(TAG, "pdu received ${data.joinToString(" ") { String.format("%02X", it) }}")
+
+                val queue = responseQueues.computeIfAbsent(opcode) { LinkedBlockingQueue() }
+                queue.offer(data)
+
+                if (opcode == 0x1B.toByte()) {
+                    if (data.size >= 3) {
+                        val handle = data[1]
+                        val value = if (data.size > 3) data.copyOfRange(3, data.size) else ByteArray(0)
+                        Log.d(TAG, "notification/indication handle=0x${String.format("%02X", handle)} value=${value.toHexString()}")
+                        try {
+                            onNotificationReceived?.invoke(handle, value)
+                        } catch (t: Throwable) {
+                            Log.e(TAG, "onNotificationReceived threw: ${t.message}", t)
                         }
                     } else {
-                        // not a notification -> treat as a response for pending request(s)
-                        responses.put(pdu)
+                        Log.w(TAG, "notification PDU too short: ${data.joinToString(" ") { String.format("%02X", it) }}")
                     }
-                } catch (e: Exception) {
-                    Log.w(TAG, "Error reading notification/response: ${e.message}")
-                    if (socket?.isConnected != true) break
                 }
-            }
-        }
-        if (output != null) {
-            Log.d(TAG, "sending read req for hearing aid declaration")
-            output?.write(byteArrayOf(0x0A, 0x29, 0x00))
-        }
-    }
-
-    fun disconnect() {
-        try {
-            notificationJob?.cancel()
-            socket?.close()
-        } catch (e: Exception) {
-            Log.w(TAG, "Error closing socket: ${e.message}")
-        }
-    }
-
-    fun registerListener(handle: ATTHandles, listener: (ByteArray) -> Unit) {
-        listeners.getOrPut(handle.value) { mutableListOf() }.add(listener)
-    }
-
-    fun unregisterListener(handle: ATTHandles, listener: (ByteArray) -> Unit) {
-        listeners[handle.value]?.remove(listener)
-    }
-
-    fun enableNotifications(handle: ATTHandles) {
-        write(ATTCCCDHandles.valueOf(handle.name), byteArrayOf(0x01, 0x00))
-    }
-
-    fun read(handle: ATTHandles): ByteArray {
-        val lsb = (handle.value and 0xFF).toByte()
-        val msb = ((handle.value shr 8) and 0xFF).toByte()
-        val pdu = byteArrayOf(OPCODE_READ_REQUEST, lsb, msb)
-        writeRaw(pdu)
-        // wait for response placed into responses queue by the reader coroutine
-        return readResponse()
-    }
-
-    fun write(handle: ATTHandles, value: ByteArray) {
-        val lsb = (handle.value and 0xFF).toByte()
-        val msb = ((handle.value shr 8) and 0xFF).toByte()
-        val pdu = byteArrayOf(OPCODE_WRITE_REQUEST, lsb, msb) + value
-        writeRaw(pdu)
-        // usually a Write Response (0x13) will arrive; wait for it (but discard return)
-        try {
-            readResponse()
-        } catch (e: Exception) {
-            Log.w(TAG, "No write response received: ${e.message}")
-        }
-    }
-
-    fun write(handle: ATTCCCDHandles, value: ByteArray) {
-        val lsb = (handle.value and 0xFF).toByte()
-        val msb = ((handle.value shr 8) and 0xFF).toByte()
-        val pdu = byteArrayOf(OPCODE_WRITE_REQUEST, lsb, msb) + value
-        writeRaw(pdu)
-        // usually a Write Response (0x13) will arrive; wait for it (but discard return)
-        try {
-            readResponse()
-        } catch (e: Exception) {
-            Log.w(TAG, "No write response received: ${e.message}")
-        }
-    }
-
-    private fun writeRaw(pdu: ByteArray) {
-        if (output == null) return
-        output?.write(pdu)
-        output?.flush()
-        Log.d(TAG, "writeRaw: ${pdu.joinToString(" ") { String.format("%02X", it) }}")
-    }
-
-    // rename / specialize: read raw PDU directly from input stream (blocking)
-    private fun readPDU(): ByteArray {
-        val inp = input ?: throw IllegalStateException("Not connected")
-        val buffer = ByteArray(512)
-        val len = inp.read(buffer)
-        if (len == -1) {
-            disconnect()
-            throw IllegalStateException("End of stream reached")
-        }
-        val data = buffer.copyOfRange(0, len)
-        Log.d(TAG, "readPDU: ${data.joinToString(" ") { String.format("%02X", it) }}")
-        return data
-    }
-
-    // wait for a response PDU produced by the background reader
-    private fun readResponse(timeoutMs: Long = 2000): ByteArray {
-        try {
-            val resp = responses.poll(timeoutMs, TimeUnit.MILLISECONDS)
-                ?: throw IllegalStateException("No response read from ATT socket within $timeoutMs ms")
-            Log.d(TAG, "readResponse: ${resp.joinToString(" ") { String.format("%02X", it) }}")
-            return resp.copyOfRange(1, resp.size)
-        } catch (e: InterruptedException) {
-            Thread.currentThread().interrupt()
-            throw IllegalStateException("Interrupted while waiting for ATT response", e)
-        }
-    }
-
-    private fun createBluetoothSocket(adapter: BluetoothAdapter, device: BluetoothDevice, uuid: ParcelUuid): BluetoothSocket {
-        val type = 3 // L2CAP
-        val constructorSpecs = listOf(
-            arrayOf(adapter, device, type, true, true, 31, uuid),
-            arrayOf(device, type, true, true, 31, uuid),
-            arrayOf(device, type, 1, true, true, 31, uuid),
-            arrayOf(type, 1, true, true, device, 31, uuid),
-            arrayOf(type, true, true, device, 31, uuid)
-        )
-
-        val constructors = BluetoothSocket::class.java.declaredConstructors
-        Log.d(TAG, "BluetoothSocket has ${constructors.size} constructors:")
-
-        constructors.forEachIndexed { index, constructor ->
-            val params = constructor.parameterTypes.joinToString(", ") { it.simpleName }
-            Log.d(TAG, "Constructor $index: ($params)")
-        }
-
-        var lastException: Exception? = null
-        var attemptedConstructors = 0
-
-        for ((index, params) in constructorSpecs.withIndex()) {
-            try {
-                Log.d(TAG, "Trying constructor signature #${index + 1}")
-                attemptedConstructors++
-
-                val paramTypes = params.map { it::class.javaPrimitiveType ?: it::class.java }.toTypedArray()
-                val constructor = BluetoothSocket::class.java.getDeclaredConstructor(*paramTypes)
-                constructor.isAccessible = true
-                return constructor.newInstance(*params) as BluetoothSocket
-
             } catch (e: Exception) {
-                Log.e(TAG, "Constructor signature #${index + 1} failed: ${e.message}")
-                lastException = e
+                Log.e(TAG, "error in reader loop: ${e.message}", e)
+                break
             }
         }
 
-        val errorMessage = "Failed to create BluetoothSocket after trying $attemptedConstructors constructor signatures"
-        Log.e(TAG, errorMessage)
-        throw lastException ?: IllegalStateException(errorMessage)
+        readerRunning.set(false)
+    }
+
+    private fun waitForResponse(opcode: Byte, timeoutMillis: Long): ByteArray? {
+        val queue = responseQueues.computeIfAbsent(opcode) { LinkedBlockingQueue() }
+        return try {
+            queue.poll(timeoutMillis, TimeUnit.MILLISECONDS)
+        } catch (e: Exception) {
+            e.printStackTrace()
+            null
+        }
     }
 }

android/app/src/main/java/me/kavishdevar/librepods/bluetooth/ATTManagerv2.kt

@@ -1,63 +0,0 @@
-package me.kavishdevar.librepods.bluetooth
-
-import android.util.Log
-
-private const val TAG = "ATTManagerv2"
-
-// the random disconnects were because of ATT, apparently. seems like we will have to accept no notifications for external changes (mainly amplification in hearing aid)
-object ATTManagerv2 {
-     fun readCharacteristic(handle: ATTHandles): ByteArray? {
-        val socket = BluetoothConnectionManager.getATTSocket()?: return null
-        try {
-//            socket.connect()
-            val input = socket.inputStream
-            val output = socket.outputStream
-
-            val pdu = byteArrayOf(0x0A, handle.value.toByte(), 0x00)
-            output.write(pdu)
-            output.flush()
-            Log.d(TAG, "writeRaw: ${pdu.joinToString(" ") { String.format("%02X", it) }}")
-            val buffer = ByteArray(512)
-            val len = input.read(buffer)
-            if (len == -1) {
-                throw IllegalStateException("End of stream reached")
-            }
-            val data = buffer.copyOfRange(0, len)
-//            socket.close()
-            if (data[0] != 0x0B.toByte()) {
-                throw IllegalStateException("Invalid response: ${data.joinToString(" ") { String.format("%02X", it) }}")
-            }
-            Log.d(TAG, "readPDU: ${data.joinToString(" ") { String.format("%02X", it) }}")
-            return data.copyOfRange(1, data.size)
-        } catch (e: Exception) {
-            Log.e(TAG, "Error reading characteristic: ${e.message}")
-            return null
-        }
-    }
-
-    fun writeCharacteristic(handle: ATTHandles, data: ByteArray) {
-        val socket = BluetoothConnectionManager.getATTSocket()?: return
-        try {
-//            socket.connect()
-            val input = socket.inputStream
-            val output = socket.outputStream
-            val pdu = byteArrayOf(0x12, handle.value.toByte(), 0x00) + data // 0x0 because LE
-            output.write(pdu)
-            output.flush()
-            Log.d(TAG, "writeRaw: ${pdu.joinToString(" ") { String.format("%02X", it) }}")
-            val buffer = ByteArray(512)
-            val len = input.read(buffer)
-            if (len == -1) {
-                throw IllegalStateException("End of stream reached")
-            }
-            val resp = buffer.copyOfRange(0, len)
-//            socket.close()
-            if (!resp.contentEquals(byteArrayOf(0x13))) {
-                throw IllegalStateException("Invalid response: ${resp.joinToString(" ") { String.format("%02X", it) }}")
-            }
-            Log.d(TAG, "readPDU: ${resp.joinToString(" ") { String.format("%02X", it) }}")
-        } catch (e: Exception) {
-            Log.e(TAG, "Error writing characteristic: ${e.message}")
-        }
-    }
-}

android/app/src/main/java/me/kavishdevar/librepods/data/HearingAid.kt

@@ -26,8 +26,6 @@ import kotlinx.coroutines.Job
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 import me.kavishdevar.librepods.bluetooth.ATTHandles
-import me.kavishdevar.librepods.bluetooth.ATTManager
-import me.kavishdevar.librepods.bluetooth.ATTManagerv2
 import java.io.IOException
 import java.nio.ByteBuffer
 import java.nio.ByteOrder
@@ -139,15 +137,15 @@ fun parseHearingAidSettingsResponse(data: ByteArray): HearingAidSettings? {
 }
 
 fun sendHearingAidSettings(
-//    attManager: ATTManager,
+    currentData: ByteArray,
     hearingAidSettings: HearingAidSettings,
-    debounceJob: MutableState<Job?>
+    debounceJob: MutableState<Job?>,
+    sender: (ATTHandles, ByteArray) -> Unit
 ) {
     debounceJob.value?.cancel()
     debounceJob.value = CoroutineScope(Dispatchers.IO).launch {
         delay(100)
         try {
-            val currentData = ATTManagerv2.readCharacteristic(ATTHandles.HEARING_AID)?: return@launch
             Log.d(TAG, "Current data before update: ${currentData.joinToString(" ") { String.format("%02X", it) }}")
             if (currentData.size < 104) {
                 Log.w(TAG, "Current data size ${currentData.size} too small, cannot send settings")
@@ -185,7 +183,7 @@ fun sendHearingAidSettings(
 
             Log.d(TAG, "Sending updated settings: ${currentData.joinToString(" ") { String.format("%02X", it) }}")
 
-            ATTManagerv2.writeCharacteristic(ATTHandles.HEARING_AID, currentData)
+            sender(ATTHandles.HEARING_AID, currentData)
         } catch (e: IOException) {
             e.printStackTrace()
         }

android/app/src/main/java/me/kavishdevar/librepods/data/Transparency.kt

@@ -83,7 +83,8 @@ data class TransparencySettings(
     }
 }
 
-fun parseTransparencySettingsResponse(data: ByteArray): TransparencySettings {
+fun parseTransparencySettingsResponse(data: ByteArray): TransparencySettings? {
+    if (data.size < 50) return null // 50 is arbitrary, too lazy to count
     val buffer = ByteBuffer.wrap(data).order(ByteOrder.LITTLE_ENDIAN)
 
     val enabled = buffer.float

android/app/src/main/java/me/kavishdevar/librepods/presentation/screens/HearingAidAdjustmentsScreen.kt

@@ -32,13 +32,12 @@ import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
-import androidx.compose.runtime.MutableState
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableFloatStateOf
-import androidx.compose.runtime.mutableIntStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
@@ -48,24 +47,17 @@ import dev.chrisbanes.haze.HazeState
 import dev.chrisbanes.haze.hazeSource
 import dev.chrisbanes.haze.materials.ExperimentalHazeMaterialsApi
 import kotlinx.coroutines.Job
-import kotlinx.coroutines.delay
 import me.kavishdevar.librepods.R
-import me.kavishdevar.librepods.presentation.components.StyledScaffold
-import me.kavishdevar.librepods.presentation.components.StyledSlider
-import me.kavishdevar.librepods.presentation.components.StyledToggle
-import me.kavishdevar.librepods.services.ServiceManager
 import me.kavishdevar.librepods.bluetooth.AACPManager
-import me.kavishdevar.librepods.bluetooth.ATTHandles
-import me.kavishdevar.librepods.bluetooth.ATTManagerv2
 import me.kavishdevar.librepods.data.HearingAidSettings
 import me.kavishdevar.librepods.data.parseHearingAidSettingsResponse
 import me.kavishdevar.librepods.data.sendHearingAidSettings
+import me.kavishdevar.librepods.presentation.components.StyledScaffold
+import me.kavishdevar.librepods.presentation.components.StyledSlider
+import me.kavishdevar.librepods.presentation.components.StyledToggle
 import me.kavishdevar.librepods.presentation.viewmodel.AirPodsViewModel
-import java.io.IOException
 import kotlin.io.encoding.ExperimentalEncodingApi
-import kotlin.time.Duration.Companion.milliseconds
 
-private var debounceJob: MutableState<Job?> = mutableStateOf(null)
 private const val TAG = "HearingAidAdjustments"
 
 @SuppressLint("DefaultLocale")
@@ -76,14 +68,83 @@ fun HearingAidAdjustmentsScreen(viewModel: AirPodsViewModel) {
     isSystemInDarkTheme()
     val verticalScrollState = rememberScrollState()
     val hazeState = remember { HazeState() }
-//    val attManager = ServiceManager.getService()?.attManager ?: throw IllegalStateException("ATTManager not available")
-
     val state by viewModel.uiState.collectAsState()
-
     val backdrop = rememberLayerBackdrop()
-    StyledScaffold(
-        title = stringResource(R.string.adjustments)
-    ) { spacerHeight ->
+
+    val debounceJob = remember { mutableStateOf<Job?>(null) }
+
+    val amplificationSliderValue = rememberSaveable { mutableFloatStateOf(0.5f) }
+    val balanceSliderValue = rememberSaveable { mutableFloatStateOf(0.5f) }
+    val toneSliderValue = rememberSaveable { mutableFloatStateOf(0.5f) }
+    val ambientNoiseReductionSliderValue = rememberSaveable { mutableFloatStateOf(0.0f) }
+    val conversationBoostEnabled = rememberSaveable { mutableStateOf(false) }
+    val leftEQ = rememberSaveable { mutableStateOf(FloatArray(8)) }
+    val rightEQ = rememberSaveable { mutableStateOf(FloatArray(8)) }
+    val ownVoiceAmplification = rememberSaveable { mutableFloatStateOf(0.5f) }
+
+    val initialized = rememberSaveable { mutableStateOf(false) }
+
+    val hearingAidSettings = remember { mutableStateOf(
+        HearingAidSettings(
+            leftEQ = leftEQ.value,
+            rightEQ = rightEQ.value,
+            leftAmplification = 0f,
+            rightAmplification = 0f,
+            leftTone = 0f,
+            rightTone = 0f,
+            leftConversationBoost = false,
+            rightConversationBoost = false,
+            leftAmbientNoiseReduction = 0f,
+            rightAmbientNoiseReduction = 0f,
+            netAmplification = 0f,
+            balance = 0f,
+            ownVoiceAmplification = 0f
+        )
+    ) }
+
+    LaunchedEffect(state.hearingAidData) {
+        parseHearingAidSettingsResponse(state.hearingAidData)?.let { parsed ->
+            amplificationSliderValue.floatValue = parsed.netAmplification
+            balanceSliderValue.floatValue = parsed.balance
+            toneSliderValue.floatValue = parsed.leftTone
+            ambientNoiseReductionSliderValue.floatValue = parsed.leftAmbientNoiseReduction
+            conversationBoostEnabled.value = parsed.leftConversationBoost
+            leftEQ.value = parsed.leftEQ.copyOf()
+            rightEQ.value = parsed.rightEQ.copyOf()
+            ownVoiceAmplification.floatValue = parsed.ownVoiceAmplification
+            initialized.value = true
+        }
+    }
+
+    LaunchedEffect(
+        amplificationSliderValue.floatValue,
+        balanceSliderValue.floatValue,
+        toneSliderValue.floatValue,
+        conversationBoostEnabled.value,
+        ambientNoiseReductionSliderValue.floatValue,
+        ownVoiceAmplification.floatValue
+    ) {
+        if (!initialized.value) return@LaunchedEffect
+        hearingAidSettings.value = HearingAidSettings(
+            leftEQ = leftEQ.value,
+            rightEQ = rightEQ.value,
+            leftAmplification = amplificationSliderValue.floatValue + if (balanceSliderValue.floatValue < 0) -balanceSliderValue.floatValue else 0f,
+            rightAmplification = amplificationSliderValue.floatValue + if (balanceSliderValue.floatValue > 0) balanceSliderValue.floatValue else 0f,
+            leftTone = toneSliderValue.floatValue,
+            rightTone = toneSliderValue.floatValue,
+            leftConversationBoost = conversationBoostEnabled.value,
+            rightConversationBoost = conversationBoostEnabled.value,
+            leftAmbientNoiseReduction = ambientNoiseReductionSliderValue.floatValue,
+            rightAmbientNoiseReduction = ambientNoiseReductionSliderValue.floatValue,
+            netAmplification = amplificationSliderValue.floatValue,
+            balance = balanceSliderValue.floatValue,
+            ownVoiceAmplification = ownVoiceAmplification.floatValue
+        )
+        Log.d(TAG, "Updated settings: ${hearingAidSettings.value}")
+        sendHearingAidSettings(state.hearingAidData, hearingAidSettings.value, debounceJob, viewModel::setATTCharacteristicValue)
+    }
+
+    StyledScaffold(title = stringResource(R.string.adjustments)) { spacerHeight ->
         Column(
             modifier = Modifier
                 .hazeSource(hazeState)
@@ -95,136 +156,6 @@ fun HearingAidAdjustmentsScreen(viewModel: AirPodsViewModel) {
         ) {
             Spacer(modifier = Modifier.height(spacerHeight))
 
-            val amplificationSliderValue = remember { mutableFloatStateOf(0.5f) }
-            val balanceSliderValue = remember { mutableFloatStateOf(0.5f) }
-            val toneSliderValue = remember { mutableFloatStateOf(0.5f) }
-            val ambientNoiseReductionSliderValue = remember { mutableFloatStateOf(0.0f) }
-            val conversationBoostEnabled = remember { mutableStateOf(false) }
-            val leftEQ = remember { mutableStateOf(FloatArray(8)) }
-            val rightEQ = remember { mutableStateOf(FloatArray(8)) }
-            val ownVoiceAmplification = remember { mutableFloatStateOf(0.5f) }
-
-            val initialLoadComplete = remember { mutableStateOf(false) }
-
-            val initialReadSucceeded = remember { mutableStateOf(false) }
-            val initialReadAttempts = remember { mutableIntStateOf(0) }
-
-            val hearingAidSettings = remember {
-                mutableStateOf(
-                    HearingAidSettings(
-                        leftEQ = leftEQ.value,
-                        rightEQ = rightEQ.value,
-                        leftAmplification = amplificationSliderValue.floatValue + (0.5f - balanceSliderValue.floatValue) * amplificationSliderValue.floatValue * 2,
-                        rightAmplification = amplificationSliderValue.floatValue + (balanceSliderValue.floatValue - 0.5f) * amplificationSliderValue.floatValue * 2,
-                        leftTone = toneSliderValue.floatValue,
-                        rightTone = toneSliderValue.floatValue,
-                        leftConversationBoost = conversationBoostEnabled.value,
-                        rightConversationBoost = conversationBoostEnabled.value,
-                        leftAmbientNoiseReduction = ambientNoiseReductionSliderValue.floatValue,
-                        rightAmbientNoiseReduction = ambientNoiseReductionSliderValue.floatValue,
-                        netAmplification = amplificationSliderValue.floatValue,
-                        balance = balanceSliderValue.floatValue,
-                        ownVoiceAmplification = ownVoiceAmplification.floatValue
-                    )
-                )
-            }
-
-            val hearingAidATTListener = remember {
-                object : (ByteArray) -> Unit {
-                    override fun invoke(value: ByteArray) {
-                        val parsed = parseHearingAidSettingsResponse(value)
-                        if (parsed != null) {
-                            amplificationSliderValue.floatValue = parsed.netAmplification
-                            balanceSliderValue.floatValue = parsed.balance
-                            toneSliderValue.floatValue = parsed.leftTone
-                            ambientNoiseReductionSliderValue.floatValue = parsed.leftAmbientNoiseReduction
-                            conversationBoostEnabled.value = parsed.leftConversationBoost
-                            leftEQ.value = parsed.leftEQ.copyOf()
-                            rightEQ.value = parsed.rightEQ.copyOf()
-                            ownVoiceAmplification.floatValue = parsed.ownVoiceAmplification
-                            Log.d(TAG, "Updated hearing aid settings from notification")
-                        } else {
-                            Log.w(TAG, "Failed to parse hearing aid settings from notification")
-                        }
-                    }
-                }
-            }
-
-            LaunchedEffect(amplificationSliderValue.floatValue, balanceSliderValue.floatValue, toneSliderValue.floatValue, conversationBoostEnabled.value, ambientNoiseReductionSliderValue.floatValue, ownVoiceAmplification.floatValue, initialLoadComplete.value, initialReadSucceeded.value) {
-                if (!initialLoadComplete.value) {
-                    Log.d(TAG, "Initial device load not complete - skipping send")
-                    return@LaunchedEffect
-                }
-
-                if (!initialReadSucceeded.value) {
-                    Log.d(TAG, "Initial device read not successful yet - skipping send until read succeeds")
-                    return@LaunchedEffect
-                }
-
-                hearingAidSettings.value = HearingAidSettings(
-                    leftEQ = leftEQ.value,
-                    rightEQ = rightEQ.value,
-                    leftAmplification = amplificationSliderValue.floatValue + if (balanceSliderValue.floatValue < 0) -balanceSliderValue.floatValue else 0f,
-                    rightAmplification = amplificationSliderValue.floatValue + if (balanceSliderValue.floatValue > 0) balanceSliderValue.floatValue else 0f,
-                    leftTone = toneSliderValue.floatValue,
-                    rightTone = toneSliderValue.floatValue,
-                    leftConversationBoost = conversationBoostEnabled.value,
-                    rightConversationBoost = conversationBoostEnabled.value,
-                    leftAmbientNoiseReduction = ambientNoiseReductionSliderValue.floatValue,
-                    rightAmbientNoiseReduction = ambientNoiseReductionSliderValue.floatValue,
-                    netAmplification = amplificationSliderValue.floatValue,
-                    balance = balanceSliderValue.floatValue,
-                    ownVoiceAmplification = ownVoiceAmplification.floatValue
-                )
-                Log.d(TAG, "Updated settings: ${hearingAidSettings.value}")
-                sendHearingAidSettings(hearingAidSettings.value, debounceJob)
-            }
-
-            LaunchedEffect(Unit) {
-                Log.d(TAG, "Connecting to ATT...")
-                try {
-//                    attManager.enableNotifications(ATTHandles.HEARING_AID)
-//                    attManager.registerListener(ATTHandles.HEARING_AID, hearingAidATTListener)
-
-                    var parsedSettings: HearingAidSettings? = null
-                    for (attempt in 1..3) {
-                        initialReadAttempts.intValue = attempt
-                        try {
-                            val data = ATTManagerv2.readCharacteristic(ATTHandles.HEARING_AID) ?: return@LaunchedEffect
-                            parsedSettings = parseHearingAidSettingsResponse(data = data)
-                            if (parsedSettings != null) {
-                                Log.d(TAG, "Parsed settings on attempt $attempt")
-                                break
-                            } else {
-                                Log.d(TAG, "Parsing returned null on attempt $attempt")
-                            }
-                        } catch (e: Exception) {
-                            Log.w(TAG, "Read attempt $attempt failed: ${e.message}")
-                        }
-                        delay(200.milliseconds)
-                    }
-
-                    if (parsedSettings != null) {
-                        Log.d(TAG, "Initial hearing aid settings: $parsedSettings")
-                        amplificationSliderValue.floatValue = parsedSettings.netAmplification
-                        balanceSliderValue.floatValue = parsedSettings.balance
-                        toneSliderValue.floatValue = parsedSettings.leftTone
-                        ambientNoiseReductionSliderValue.floatValue = parsedSettings.leftAmbientNoiseReduction
-                        conversationBoostEnabled.value = parsedSettings.leftConversationBoost
-                        leftEQ.value = parsedSettings.leftEQ.copyOf()
-                        rightEQ.value = parsedSettings.rightEQ.copyOf()
-                        ownVoiceAmplification.floatValue = parsedSettings.ownVoiceAmplification
-                        initialReadSucceeded.value = true
-                    } else {
-                        Log.d(TAG, "Failed to read/parse initial hearing aid settings after ${initialReadAttempts.intValue} attempts")
-                    }
-                } catch (e: IOException) {
-                    e.printStackTrace()
-                } finally {
-                    initialLoadComplete.value = true
-                }
-            }
-
             StyledSlider(
                 label = stringResource(R.string.amplification),
                 valueRange = -1f..1f,
@@ -237,7 +168,6 @@ fun HearingAidAdjustmentsScreen(viewModel: AirPodsViewModel) {
                 independent = true,
             )
 
-
             StyledToggle(
                 label = stringResource(R.string.swipe_to_control_amplification),
                 checked = state.controlStates[AACPManager.Companion.ControlCommandIdentifiers.HPS_GAIN_SWIPE]?.getOrNull(0) == 0x01.toByte(),

android/app/src/main/java/me/kavishdevar/librepods/presentation/screens/HearingAidScreen.kt

@@ -259,6 +259,10 @@ fun HearingAidScreen(viewModel: AirPodsViewModel, navController: NavController)
                         return@launch
                     }
                     val parsed = parseTransparencySettingsResponse(state.hearingAidData)
+                    if (parsed == null) {
+                        Log.w(TAG, "transparency parse failed")
+                        return@launch
+                    }
                     val disabledSettings = parsed.copy(enabled = false)
                     sendTransparencySettings(viewModel::setATTCharacteristicValue, disabledSettings)
                 } catch (e: Exception) {

android/app/src/main/java/me/kavishdevar/librepods/presentation/screens/TransparencySettingsScreen.kt

@@ -46,9 +46,10 @@ import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableFloatStateOf
-import androidx.compose.runtime.mutableIntStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.Saver
+import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.shadow
@@ -64,17 +65,14 @@ import com.kyant.backdrop.backdrops.layerBackdrop
 import com.kyant.backdrop.backdrops.rememberLayerBackdrop
 import dev.chrisbanes.haze.hazeSource
 import dev.chrisbanes.haze.materials.ExperimentalHazeMaterialsApi
-import kotlinx.coroutines.delay
-import me.kavishdevar.librepods.BuildConfig
 import me.kavishdevar.librepods.R
-import me.kavishdevar.librepods.presentation.components.StyledScaffold
-import me.kavishdevar.librepods.presentation.components.StyledSlider
-import me.kavishdevar.librepods.presentation.components.StyledToggle
 import me.kavishdevar.librepods.data.TransparencySettings
 import me.kavishdevar.librepods.data.parseTransparencySettingsResponse
 import me.kavishdevar.librepods.data.sendTransparencySettings
+import me.kavishdevar.librepods.presentation.components.StyledScaffold
+import me.kavishdevar.librepods.presentation.components.StyledSlider
+import me.kavishdevar.librepods.presentation.components.StyledToggle
 import me.kavishdevar.librepods.presentation.viewmodel.AirPodsViewModel
-import java.io.IOException
 import kotlin.io.encoding.ExperimentalEncodingApi
 
 private const val TAG = "TransparencySettings"
@@ -112,19 +110,26 @@ fun TransparencySettingsScreen(viewModel: AirPodsViewModel) {
             Spacer(modifier = Modifier.height(topPadding))
             val backgroundColor = if (isDarkTheme) Color(0xFF1C1C1E) else Color(0xFFFFFFFF)
 
-            val enabled = remember { mutableStateOf(false) }
-            val amplificationSliderValue = remember { mutableFloatStateOf(0.5f) }
-            val balanceSliderValue = remember { mutableFloatStateOf(0.5f) }
-            val toneSliderValue = remember { mutableFloatStateOf(0.5f) }
-            val ambientNoiseReductionSliderValue = remember { mutableFloatStateOf(0.0f) }
-            val conversationBoostEnabled = remember { mutableStateOf(false) }
-            val eq = remember { mutableStateOf(FloatArray(8)) }
-            val phoneMediaEQ = remember { mutableStateOf(FloatArray(8) { 0.5f }) }
+            val enabled = rememberSaveable { mutableStateOf(false) }
+            val amplificationSliderValue = rememberSaveable { mutableFloatStateOf(0.5f) }
+            val balanceSliderValue = rememberSaveable { mutableFloatStateOf(0.5f) }
+            val toneSliderValue = rememberSaveable { mutableFloatStateOf(0.5f) }
+            val ambientNoiseReductionSliderValue = rememberSaveable { mutableFloatStateOf(0.0f) }
+            val conversationBoostEnabled = rememberSaveable { mutableStateOf(false) }
+            val eq = rememberSaveable(
+                saver = Saver(
+                    save = { it.value.toList() },
+                    restore = { mutableStateOf(it.toFloatArray()) }
+                )
+            ) { mutableStateOf(FloatArray(8)) }
+            val phoneMediaEQ = rememberSaveable(
+                saver = Saver(
+                    save = { it.value.toList() },
+                    restore = { mutableStateOf(it.toFloatArray()) }
+                )
+            ) { mutableStateOf(FloatArray(8) { 0.5f }) }
 
-            val initialLoadComplete = remember { mutableStateOf(false) }
-
-            val initialReadSucceeded = remember { mutableStateOf(false) }
-            val initialReadAttempts = remember { mutableIntStateOf(0) }
+            val initialized = rememberSaveable { mutableStateOf(false) }
 
             val transparencySettings = remember {
                 mutableStateOf(
@@ -153,23 +158,9 @@ fun TransparencySettingsScreen(viewModel: AirPodsViewModel) {
                 toneSliderValue.floatValue,
                 conversationBoostEnabled.value,
                 ambientNoiseReductionSliderValue.floatValue,
-                eq.value,
-                initialLoadComplete.value,
-                initialReadSucceeded.value
+                eq.value
             ) {
-                if (!initialLoadComplete.value) {
-                    Log.d(TAG, "Initial device load not complete - skipping send")
-                    return@LaunchedEffect
-                }
-
-                if (!initialReadSucceeded.value) {
-                    Log.d(
-                        TAG,
-                        "Initial device read not successful yet - skipping send until read succeeds"
-                    )
-                    return@LaunchedEffect
-                }
-
+                if (!initialized.value) return@LaunchedEffect
                 transparencySettings.value = TransparencySettings(
                     enabled = enabled.value,
                     leftEQ = eq.value,
@@ -189,59 +180,20 @@ fun TransparencySettingsScreen(viewModel: AirPodsViewModel) {
                 sendTransparencySettings(viewModel::setATTCharacteristicValue, transparencySettings.value)
             }
 
-            LaunchedEffect(Unit) {
-                Log.d(TAG, "Connecting to ATT...")
-                try {
-                    // If we have an AACP manager, prefer its EQ data to populate EQ controls first
-                    try {
-                        Log.d(TAG, "Found AACPManager, reading cached EQ data")
-                        val aacpEQ = state.eqData
-                        if (aacpEQ.isNotEmpty()) {
-                            eq.value = aacpEQ.copyOf()
-                            phoneMediaEQ.value = aacpEQ.copyOf()
-                            Log.d(TAG, "Populated EQ from AACPManager: ${aacpEQ.toList()}")
-                        } else {
-                            Log.d(TAG, "AACPManager EQ data empty")
-                        }
-                    } catch (e: Exception) {
-                        Log.w(TAG, "Error reading EQ from AACPManager: ${e.message}")
-                    }
-
-                    var parsedSettings: TransparencySettings? = null
-                    for (attempt in 1..3) {
-                        initialReadAttempts.intValue = attempt
-                        try {
-                            val data = state.transparencyData
-                            parsedSettings = parseTransparencySettingsResponse(data = data)
-                            Log.d(TAG, "Parsed settings on attempt $attempt")
-                        } catch (e: Exception) {
-                            Log.w(TAG, "Read attempt $attempt failed: ${e.message}")
-                        }
-                        delay(200)
-                    }
-
-                    if (parsedSettings != null) {
-                        Log.d(TAG, "Initial transparency settings: $parsedSettings")
-                        enabled.value = parsedSettings.enabled
-                        amplificationSliderValue.floatValue = parsedSettings.netAmplification
-                        balanceSliderValue.floatValue = parsedSettings.balance
-                        toneSliderValue.floatValue = parsedSettings.leftTone
-                        ambientNoiseReductionSliderValue.floatValue =
-                            parsedSettings.leftAmbientNoiseReduction
-                        conversationBoostEnabled.value = parsedSettings.leftConversationBoost
-                        eq.value = parsedSettings.leftEQ.copyOf()
-                        initialReadSucceeded.value = true
-                    } else {
-                        Log.d(
-                            TAG,
-                            "Failed to read/parse initial transparency settings after ${initialReadAttempts.intValue} attempts"
-                        )
-                    }
-                } catch (e: IOException) {
-                    e.printStackTrace()
-                } finally {
-                    initialLoadComplete.value = true
+            LaunchedEffect(state.transparencyData) {
+                val parsedSettings = parseTransparencySettingsResponse(data = state.transparencyData) ?: return@LaunchedEffect
+                Log.d(TAG, "Initial transparency settings: $parsedSettings")
+                enabled.value = parsedSettings.enabled
+                amplificationSliderValue.floatValue = parsedSettings.netAmplification
+                balanceSliderValue.floatValue = parsedSettings.balance
+                toneSliderValue.floatValue = parsedSettings.leftTone
+                ambientNoiseReductionSliderValue.floatValue =
+                    parsedSettings.leftAmbientNoiseReduction
+                conversationBoostEnabled.value = parsedSettings.leftConversationBoost
+                if (!eq.value.contentEquals(parsedSettings.leftEQ)) {
+                    eq.value = parsedSettings.leftEQ.copyOf()
                 }
+                initialized.value = true
             }
 
             if (state.vendorIdHook) {

android/app/src/main/java/me/kavishdevar/librepods/presentation/screens/UpdateHearingTestScreen.kt

@@ -35,13 +35,14 @@ import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
-import androidx.compose.runtime.MutableState
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableFloatStateOf
-import androidx.compose.runtime.mutableIntStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.Saver
+import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
@@ -57,35 +58,19 @@ import com.kyant.backdrop.backdrops.layerBackdrop
 import com.kyant.backdrop.backdrops.rememberLayerBackdrop
 import dev.chrisbanes.haze.hazeSource
 import kotlinx.coroutines.Job
-import kotlinx.coroutines.delay
 import me.kavishdevar.librepods.R
-import me.kavishdevar.librepods.presentation.components.StyledScaffold
-import me.kavishdevar.librepods.services.ServiceManager
-import me.kavishdevar.librepods.bluetooth.ATTHandles
-import me.kavishdevar.librepods.bluetooth.ATTManagerv2
 import me.kavishdevar.librepods.data.HearingAidSettings
 import me.kavishdevar.librepods.data.parseHearingAidSettingsResponse
 import me.kavishdevar.librepods.data.sendHearingAidSettings
-import java.io.IOException
+import me.kavishdevar.librepods.presentation.components.StyledScaffold
+import me.kavishdevar.librepods.presentation.viewmodel.AirPodsViewModel
 
-private var debounceJob: MutableState<Job?> = mutableStateOf(null)
 private const val TAG = "HearingAidAdjustments"
 
 @Composable
-fun UpdateHearingTestScreen() {
+fun UpdateHearingTestScreen(viewModel: AirPodsViewModel) {
     val verticalScrollState = rememberScrollState()
-//    val attManager = ServiceManager.getService()?.attManager
-//    if (attManager == null) {
-//        Text(
-//            text = stringResource(R.string.att_manager_is_null_try_reconnecting),
-//            modifier = Modifier
-//                .fillMaxSize()
-//                .padding(16.dp),
-//            textAlign = TextAlign.Center
-//        )
-//        return
-//    }
-
+    val state by viewModel.uiState.collectAsState()
     val backdrop = rememberLayerBackdrop()
     StyledScaffold(
         title = stringResource(R.string.hearing_test)
@@ -113,18 +98,31 @@ fun UpdateHearingTestScreen() {
                 ),
                 textAlign = TextAlign.Center,
             )
-            val tone = remember { mutableFloatStateOf(0.5f) }
-            val ambientNoiseReduction = remember { mutableFloatStateOf(0.0f) }
-            val ownVoiceAmplification = remember { mutableFloatStateOf(0.5f) }
-            val leftAmplification = remember { mutableFloatStateOf(0.5f) }
-            val rightAmplification = remember { mutableFloatStateOf(0.5f) }
-            val conversationBoostEnabled = remember { mutableStateOf(false) }
-            val leftEQ = remember { mutableStateOf(FloatArray(8)) }
-            val rightEQ = remember { mutableStateOf(FloatArray(8)) }
+            val tone = rememberSaveable { mutableFloatStateOf(0.5f) }
+            val ambientNoiseReduction = rememberSaveable { mutableFloatStateOf(0.0f) }
+            val ownVoiceAmplification = rememberSaveable { mutableFloatStateOf(0.5f) }
+            val leftAmplification = rememberSaveable { mutableFloatStateOf(0.5f) }
+            val rightAmplification = rememberSaveable { mutableFloatStateOf(0.5f) }
+            val conversationBoostEnabled = rememberSaveable { mutableStateOf(false) }
+            val leftEQ = rememberSaveable(
+                saver = Saver(
+                    save = { it.value.toList() },
+                    restore = { mutableStateOf(it.toFloatArray()) }
+                )
+            ) {
+                mutableStateOf(FloatArray(8))
+            }
+            val rightEQ = rememberSaveable(
+                saver = Saver(
+                    save = { it.value.toList() },
+                    restore = { mutableStateOf(it.toFloatArray()) }
+                )
+            ) {
+                mutableStateOf(FloatArray(8))
+            }
 
-            val initialLoadComplete = remember { mutableStateOf(false) }
-            val initialReadSucceeded = remember { mutableStateOf(false) }
-            val initialReadAttempts = remember { mutableIntStateOf(0) }
+            val debounceJob = remember { mutableStateOf<Job?>(null) }
+            val initialized = rememberSaveable { mutableStateOf(false) }
 
             val hearingAidSettings = remember {
                 mutableStateOf(
@@ -146,59 +144,35 @@ fun UpdateHearingTestScreen() {
                 )
             }
 
-            val hearingAidATTListener = remember {
-                object : (ByteArray) -> Unit {
-                    override fun invoke(value: ByteArray) {
-                        val parsed = parseHearingAidSettingsResponse(value)
-                        if (parsed != null) {
-                            leftEQ.value = parsed.leftEQ.copyOf()
-                            rightEQ.value = parsed.rightEQ.copyOf()
-                            conversationBoostEnabled.value = parsed.leftConversationBoost
-                            tone.floatValue = parsed.leftTone
-                            ambientNoiseReduction.floatValue = parsed.leftAmbientNoiseReduction
-                            ownVoiceAmplification.floatValue = parsed.ownVoiceAmplification
-                            leftAmplification.floatValue = parsed.leftAmplification
-                            rightAmplification.floatValue = parsed.rightAmplification
-                            Log.d(TAG, "Updated hearing aid settings from notification")
-                        } else {
-                            Log.w(TAG, "Failed to parse hearing aid settings from notification")
-                        }
-                    }
+            LaunchedEffect(state.hearingAidData) {
+                val parsed = parseHearingAidSettingsResponse(state.hearingAidData)
+                if (parsed != null) {
+                    leftEQ.value = parsed.leftEQ.copyOf()
+                    rightEQ.value = parsed.rightEQ.copyOf()
+                    conversationBoostEnabled.value = parsed.leftConversationBoost
+                    tone.floatValue = parsed.leftTone
+                    ambientNoiseReduction.floatValue = parsed.leftAmbientNoiseReduction
+                    ownVoiceAmplification.floatValue = parsed.ownVoiceAmplification
+                    leftAmplification.floatValue = parsed.leftAmplification
+                    rightAmplification.floatValue = parsed.rightAmplification
+                    initialized.value = true
+                    Log.d(TAG, "Updated hearing aid settings from notification")
+                } else {
+                    Log.w(TAG, "Failed to parse hearing aid settings from notification")
                 }
             }
 
-
-//            DisposableEffect(Unit) {
-//                onDispose {
-//                    attManager.unregisterListener(ATTHandles.HEARING_AID, hearingAidATTListener)
-//                }
-//            }
-
             LaunchedEffect(
                 leftEQ.value,
                 rightEQ.value,
                 conversationBoostEnabled.value,
-                initialLoadComplete.value,
-                initialReadSucceeded.value,
                 leftAmplification.floatValue,
                 rightAmplification.floatValue,
                 tone.floatValue,
                 ambientNoiseReduction.floatValue,
                 ownVoiceAmplification.floatValue
             ) {
-                if (!initialLoadComplete.value) {
-                    Log.d(TAG, "Initial device load not complete - skipping send")
-                    return@LaunchedEffect
-                }
-
-                if (!initialReadSucceeded.value) {
-                    Log.d(
-                        TAG,
-                        "Initial device read not successful yet - skipping send until read succeeds"
-                    )
-                    return@LaunchedEffect
-                }
-
+                if (!initialized.value) return@LaunchedEffect
                 hearingAidSettings.value = HearingAidSettings(
                     leftEQ = leftEQ.value,
                     rightEQ = rightEQ.value,
@@ -215,55 +189,7 @@ fun UpdateHearingTestScreen() {
                     ownVoiceAmplification = ownVoiceAmplification.floatValue
                 )
                 Log.d(TAG, "Updated settings: ${hearingAidSettings.value}")
-                sendHearingAidSettings(hearingAidSettings.value, debounceJob)
-            }
-
-            LaunchedEffect(Unit) {
-                Log.d(TAG, "Connecting to ATT...")
-                try {
-//                    attManager.enableNotifications(ATTHandles.HEARING_AID)
-//                    attManager.registerListener(ATTHandles.HEARING_AID, hearingAidATTListener)
-
-                    var parsedSettings: HearingAidSettings? = null
-                    for (attempt in 1..3) {
-                        initialReadAttempts.intValue = attempt
-                        try {
-                            val data = ATTManagerv2.readCharacteristic(ATTHandles.HEARING_AID)?: byteArrayOf()
-                            parsedSettings = parseHearingAidSettingsResponse(data = data)
-                            if (parsedSettings != null) {
-                                Log.d(TAG, "Parsed settings on attempt $attempt")
-                                break
-                            } else {
-                                Log.d(TAG, "Parsing returned null on attempt $attempt")
-                            }
-                        } catch (e: Exception) {
-                            Log.w(TAG, "Read attempt $attempt failed: ${e.message}")
-                        }
-                        delay(200)
-                    }
-
-                    if (parsedSettings != null) {
-                        Log.d(TAG, "Initial hearing aid settings: $parsedSettings")
-                        leftEQ.value = parsedSettings.leftEQ.copyOf()
-                        rightEQ.value = parsedSettings.rightEQ.copyOf()
-                        conversationBoostEnabled.value = parsedSettings.leftConversationBoost
-                        tone.floatValue = parsedSettings.leftTone
-                        ambientNoiseReduction.floatValue = parsedSettings.leftAmbientNoiseReduction
-                        ownVoiceAmplification.floatValue = parsedSettings.ownVoiceAmplification
-                        leftAmplification.floatValue = parsedSettings.leftAmplification
-                        rightAmplification.floatValue = parsedSettings.rightAmplification
-                        initialReadSucceeded.value = true
-                    } else {
-                        Log.d(
-                            TAG,
-                            "Failed to read/parse initial hearing aid settings after ${initialReadAttempts.intValue} attempts"
-                        )
-                    }
-                } catch (e: IOException) {
-                    e.printStackTrace()
-                } finally {
-                    initialLoadComplete.value = true
-                }
+                sendHearingAidSettings(state.hearingAidData, hearingAidSettings.value, debounceJob, viewModel::setATTCharacteristicValue)
             }
 
             val frequencies =

android/app/src/main/java/me/kavishdevar/librepods/presentation/viewmodel/AirPodsViewModel.kt

@@ -29,7 +29,6 @@ import androidx.core.content.edit
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
@@ -39,8 +38,8 @@ import me.kavishdevar.librepods.BuildConfig
 import me.kavishdevar.librepods.billing.BillingManager
 import me.kavishdevar.librepods.bluetooth.AACPManager
 import me.kavishdevar.librepods.bluetooth.AACPManager.Companion.ControlCommandIdentifiers
+import me.kavishdevar.librepods.bluetooth.ATTCCCDHandles
 import me.kavishdevar.librepods.bluetooth.ATTHandles
-import me.kavishdevar.librepods.bluetooth.ATTManagerv2
 import me.kavishdevar.librepods.data.AirPodsInstance
 import me.kavishdevar.librepods.data.AirPodsModels
 import me.kavishdevar.librepods.data.AirPodsNotifications
@@ -52,7 +51,6 @@ import me.kavishdevar.librepods.data.ControlCommandRepository
 import me.kavishdevar.librepods.data.StemAction
 import me.kavishdevar.librepods.data.XposedRemotePrefProvider
 import me.kavishdevar.librepods.services.AirPodsService
-import kotlin.time.Duration.Companion.milliseconds
 
 @Suppress("ArrayInDataClass")
 data class AirPodsUiState(
@@ -147,6 +145,7 @@ class AirPodsViewModel(
         loadSharedPreferences()
         setupControlObservers()
         loadControlList()
+        loadATT()
         observeATT()
         observeSharedPreferences()
         observeBilling()
@@ -527,27 +526,36 @@ class AirPodsViewModel(
     }
 
     fun setATTCharacteristicValue(handle: ATTHandles, value: ByteArray) {
-        if (handle == ATTHandles.LOUD_SOUND_REDUCTION) {
-            _uiState.update { it.copy(loudSoundReductionEnabled = value[0].toInt() == 0x01) }
+        when (handle) {
+            // ideally should be using a different viewmodel for ATT based things because there are a lot of values, and I am not going to add all to this state, but there's loudsoundreduction.
+            ATTHandles.LOUD_SOUND_REDUCTION -> {
+                _uiState.value = _uiState.value.copy(loudSoundReductionEnabled = value[0].toInt() == 0x01)
+            }
+            ATTHandles.HEARING_AID -> {
+                _uiState.value = _uiState.value.copy(hearingAidData = value)
+            }
+            ATTHandles.TRANSPARENCY -> {
+                _uiState.value = _uiState.value.copy(transparencyData = value)
+            }
         }
         viewModelScope.launch(Dispatchers.IO) {
             try {
-                ATTManagerv2.writeCharacteristic(handle, value)
+                service.attManager.writeCharacteristic(handle, value)
             } catch (e: Exception) {
                 e.printStackTrace()
             }
         }
     }
 
-    fun refreshATT() {
-        viewModelScope.launch(Dispatchers.IO) {
-            val loudSoundReduction = ATTManagerv2.readCharacteristic(ATTHandles.LOUD_SOUND_REDUCTION) ?: byteArrayOf()
-            val loudSoundReductionEnabled = if (loudSoundReduction.isNotEmpty()) {
-                    loudSoundReduction[0].toInt() == 1
-            } else false
-            val transparencyData = ATTManagerv2.readCharacteristic(ATTHandles.TRANSPARENCY)?: byteArrayOf()
-            val hearingAidData = ATTManagerv2.readCharacteristic(ATTHandles.HEARING_AID)?:byteArrayOf()
-            _uiState.value = _uiState.value.copy(
+    fun loadATT() {
+        val loudSoundReduction = service.attManager.getCharacteristic(ATTHandles.LOUD_SOUND_REDUCTION) ?: byteArrayOf()
+        val loudSoundReductionEnabled = if (loudSoundReduction.isNotEmpty()) {
+            loudSoundReduction[0].toInt() == 1
+        } else false
+        val hearingAidData = service.attManager.getCharacteristic(ATTHandles.HEARING_AID) ?: byteArrayOf()
+        val transparencyData = service.attManager.getCharacteristic(ATTHandles.TRANSPARENCY) ?: byteArrayOf()
+        _uiState.update {
+            it.copy(
                 loudSoundReductionEnabled = loudSoundReductionEnabled,
                 transparencyData = transparencyData,
                 hearingAidData = hearingAidData
@@ -557,9 +565,30 @@ class AirPodsViewModel(
 
     fun observeATT() {
         viewModelScope.launch(Dispatchers.IO) {
-            while (true) {
-                refreshATT()
-                delay(15000.milliseconds)
+            service.attManager.enableNotification(ATTCCCDHandles.HEARING_AID)
+            service.attManager.enableNotification(ATTCCCDHandles.TRANSPARENCY)
+//            service.attManager.enableNotification(ATTCCCDHandles.LOUD_SOUND_REDUCTION)
+        }
+        service.attManager.setOnNotificationReceived { handle, value ->
+            when (handle) {
+                ATTHandles.LOUD_SOUND_REDUCTION.value.toByte() -> {
+                    val loudSoundReductionEnabled = if (value.isNotEmpty()) {
+                        value[0].toInt() == 1
+                    } else false
+                    _uiState.update {
+                        it.copy(loudSoundReductionEnabled = loudSoundReductionEnabled)
+                    }
+                }
+                ATTHandles.HEARING_AID.value.toByte() -> {
+                    _uiState.update {
+                        it.copy(hearingAidData = value)
+                    }
+                }
+                ATTHandles.TRANSPARENCY.value.toByte() -> {
+                    _uiState.update {
+                        it.copy(transparencyData = value)
+                    }
+                }
             }
         }
     }

android/app/src/main/java/me/kavishdevar/librepods/services/AirPodsService.kt

@@ -85,7 +85,9 @@ import me.kavishdevar.librepods.MainActivity
 import me.kavishdevar.librepods.R
 import me.kavishdevar.librepods.bluetooth.AACPManager
 import me.kavishdevar.librepods.bluetooth.AACPManager.Companion.StemPressType
-import me.kavishdevar.librepods.bluetooth.ATTManager
+import me.kavishdevar.librepods.bluetooth.ATTCCCDHandles
+import me.kavishdevar.librepods.bluetooth.ATTHandles
+import me.kavishdevar.librepods.bluetooth.ATTManagerv2
 import me.kavishdevar.librepods.bluetooth.BLEManager
 import me.kavishdevar.librepods.bluetooth.BluetoothConnectionManager
 import me.kavishdevar.librepods.data.AirPodsInstance
@@ -126,7 +128,6 @@ import me.kavishdevar.librepods.utils.SystemApisUtils.METADATA_UNTETHERED_RIGHT_
 import me.kavishdevar.librepods.utils.SystemApisUtils.METADATA_UNTETHERED_RIGHT_LOW_BATTERY_THRESHOLD
 import java.nio.ByteBuffer
 import java.nio.ByteOrder
-import java.time.LocalDateTime
 import kotlin.io.encoding.Base64
 import kotlin.io.encoding.ExperimentalEncodingApi
 import kotlin.time.Duration.Companion.milliseconds
@@ -152,6 +153,7 @@ class AirPodsService : Service(), SharedPreferences.OnSharedPreferenceChangeList
     var macAddress = ""
     var localMac = ""
     lateinit var aacpManager: AACPManager
+    lateinit var attManager: ATTManagerv2
     var airpodsInstance: AirPodsInstance? = null
     var cameraActive = false
     private var disconnectedBecauseReversed = false
@@ -380,6 +382,8 @@ class AirPodsService : Service(), SharedPreferences.OnSharedPreferenceChangeList
         aacpManager = AACPManager()
         initializeAACPManagerCallback()
 
+        attManager = ATTManagerv2()
+
         sharedPreferences.registerOnSharedPreferenceChangeListener(this)
 
         localMac = config.selfMacAddress
@@ -693,7 +697,7 @@ class AirPodsService : Service(), SharedPreferences.OnSharedPreferenceChangeList
                     popupShown = false
                     updateNotificationContent(false)
                     aacpManager.disconnected()
-                    BluetoothConnectionManager.getATTSocket()?.close()
+                    attManager.disconnected()
                     BluetoothConnectionManager.setCurrentConnection(null, null)
                 }
             }
@@ -2702,6 +2706,15 @@ class AirPodsService : Service(), SharedPreferences.OnSharedPreferenceChangeList
                         } else null
                         attSocket?.connect()
                         BluetoothConnectionManager.setCurrentConnection(socket, attSocket)
+                        if (attSocket != null) {
+                            attManager.startReader()
+                            attManager.readCharacteristic(ATTHandles.LOUD_SOUND_REDUCTION)
+                            attManager.readCharacteristic(ATTHandles.TRANSPARENCY)
+                            attManager.readCharacteristic(ATTHandles.HEARING_AID)
+                            attManager.enableNotification(ATTCCCDHandles.HEARING_AID)
+//                            attManager.enableNotification(ATTCCCDHandles.LOUD_SOUND_REDUCTION)
+                            attManager.enableNotification(ATTCCCDHandles.TRANSPARENCY)
+                        }
 
                         // Create AirPodsInstance from stored config if available
                         if (airpodsInstance == null && config.airpodsModelNumber.isNotEmpty()) {
@@ -2906,7 +2919,7 @@ class AirPodsService : Service(), SharedPreferences.OnSharedPreferenceChangeList
         socket.close()
 //        isConnectedLocally = false
         aacpManager.disconnected()
-        BluetoothConnectionManager.getATTSocket()?.close()
+        attManager.disconnected()
         BluetoothConnectionManager.setCurrentConnection(null, null)
         updateNotificationContent(false)
         sendBroadcast(Intent(AirPodsNotifications.AIRPODS_DISCONNECTED).apply {