Attempt casual MAC based re-recognition and assign a semi persistent identifier.

app/src/main/java/eu/darken/capod/pods/core/PodDevice.kt

@@ -2,13 +2,31 @@ package eu.darken.capod.pods.core
 
 import android.bluetooth.le.ScanResult
 import android.content.Context
+import androidx.annotation.DrawableRes
+import eu.darken.capod.R
+import java.time.Instant
+import java.util.*
+import kotlin.math.abs
 
 interface PodDevice {
 
+    val identifier: UUID
+
     val scanResult: ScanResult
 
+    val lastSeenAt: Instant
+
     val rssi: Int
         get() = scanResult.rssi
 
+    fun getSignalQuality(context: Context): String {
+        val percentage = (100 - abs(rssi))
+        return "~$percentage%"
+    }
+
     fun getLabel(context: Context): String
+
+    @get:DrawableRes
+    val iconRes: Int
+        get() = R.drawable.ic_baseline_earbuds_24
 }

app/src/main/java/eu/darken/capod/pods/core/airpods/AirPodsFactory.kt

@@ -1,10 +1,9 @@
 package eu.darken.capod.pods.core.airpods
 
 import android.bluetooth.le.ScanResult
-import dagger.Reusable
+import android.os.SystemClock
 import eu.darken.capod.common.debug.Bugs
-import eu.darken.capod.common.debug.logging.Logging.Priority.INFO
-import eu.darken.capod.common.debug.logging.Logging.Priority.WARN
+import eu.darken.capod.common.debug.logging.Logging.Priority.*
 import eu.darken.capod.common.debug.logging.asLog
 import eu.darken.capod.common.debug.logging.log
 import eu.darken.capod.common.debug.logging.logTag
@@ -15,28 +14,42 @@ import eu.darken.capod.pods.core.airpods.models.AirPodsPro
 import eu.darken.capod.pods.core.airpods.models.UnknownAppleDevice
 import eu.darken.capod.pods.core.airpods.protocol.ContinuityProtocol
 import eu.darken.capod.pods.core.airpods.protocol.ProximityPairing
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import java.time.Duration
+import java.util.*
 import javax.inject.Inject
+import javax.inject.Singleton
 
-@Reusable
+@Singleton
 class AirPodsFactory @Inject constructor(
     private val continuityProtocolDecoder: ContinuityProtocol.Decoder,
     private val proximityPairingDecoder: ProximityPairing.Decoder
 ) {
 
-    data class Message(
-        // 0x07 ; AirPods message1 byte
-        // 25; Length 1byte
-        // 0x01
-        val type: UByte,
-        val deviceModel: UShort,
-        val status: UByte,
-        val batteryIndicator: UShort,
-        val lidCount: UByte,
-        val deviceColor: UByte,
-        val encryptedData: UShort,
-    )
+    data class KnownDevice(
+        val identifier: UUID,
+        val scanResult: ScanResult
+    ) {
+        val address: String
+            get() = scanResult.device.address
 
-    suspend fun create(scanResult: ScanResult): PodDevice? {
+        val rssi: Int
+            get() = scanResult.rssi
+
+        val timestampNanos: Duration
+            get() = Duration.ofNanos(scanResult.timestampNanos)
+
+        fun isOlderThan(age: Duration): Boolean {
+            val now = Duration.ofNanos(SystemClock.elapsedRealtimeNanos())
+            return now - timestampNanos > age
+        }
+    }
+
+    private val knownDevs = mutableMapOf<UUID, KnownDevice>()
+    private val mutex = Mutex()
+
+    private suspend fun getMessage(scanResult: ScanResult): ProximityPairing.Message? {
         val messages = try {
             continuityProtocolDecoder.decode(scanResult)
         } catch (e: Exception) {
@@ -58,6 +71,58 @@ class AirPodsFactory @Inject constructor(
             return null
         }
 
+        return proximityMessage
+    }
+
+    private suspend fun recognizeDevice(scanResult: ScanResult): UUID {
+        val address = scanResult.device.address
+
+        var identifier: UUID? = null
+
+        knownDevs.values.firstOrNull { it.address == address }?.let {
+            log(TAG, VERBOSE) { "recognizeDevice: Recovered previous ID via address: $it" }
+            knownDevs[it.identifier] = it.copy(scanResult = scanResult)
+            identifier = it.identifier
+        }
+
+        if (identifier == null) {
+            knownDevs.values
+                .firstOrNull {
+                    it.rssi > -60 && !it.isOlderThan(Duration.ofSeconds(10))
+                }
+                ?.let {
+                    log(TAG, VERBOSE) { "recognizeDevice: Close match based on RSSI and timestamp." }
+                    knownDevs[it.identifier] = it.copy(scanResult = scanResult)
+                    identifier = it.identifier
+                }
+        }
+
+
+        if (identifier == null) {
+            log(TAG, VERBOSE) { "recognizeDevice: Mapping as new device" }
+            identifier = UUID.randomUUID()
+        }
+
+        knownDevs[identifier!!] = KnownDevice(
+            identifier = identifier!!,
+            scanResult = scanResult
+        )
+
+        knownDevs.values.toList().forEach { knownDevice ->
+            if (knownDevice.isOlderThan(Duration.ofSeconds(20))) {
+                log(TAG, VERBOSE) { "recognizeDevice: Removing stale known device: $knownDevice" }
+                knownDevs.remove(knownDevice.identifier)
+            }
+        }
+
+        return identifier!!
+    }
+
+    suspend fun create(scanResult: ScanResult): PodDevice? = mutex.withLock {
+        val pm = getMessage(scanResult) ?: return@withLock null
+
+        val identifier = recognizeDevice(scanResult)
+
         log(TAG, INFO) {
             val data = scanResult.scanRecord!!.getManufacturerSpecificData(
                 ContinuityProtocol.APPLE_COMPANY_IDENTIFIER
@@ -69,14 +134,26 @@ class AirPodsFactory @Inject constructor(
         }
 
         val dm = (
-                ((proximityMessage.data[1].toInt() and 255) shl 8) or (proximityMessage.data[2].toInt() and 255)
+                ((pm.data[1].toInt() and 255) shl 8) or (pm.data[2].toInt() and 255)
                 ).toUShort()
-        val dmDirty = proximityMessage.data[1]
+        val dmDirty = pm.data[1]
 
         return when {
-            dm == 0x0220.toUShort() || dmDirty == 2.toUByte() -> AirPodsGen1(scanResult, proximityMessage)
-            dm == 0x0F20.toUShort() || dmDirty == 15.toUByte() -> AirPodsGen2(scanResult, proximityMessage)
-            dm == 0x0e20.toUShort() || dmDirty == 14.toUByte() -> AirPodsPro(scanResult, proximityMessage)
+            dm == 0x0220.toUShort() || dmDirty == 2.toUByte() -> AirPodsGen1(
+                identifier = identifier,
+                scanResult = scanResult,
+                proximityMessage = pm
+            )
+            dm == 0x0F20.toUShort() || dmDirty == 15.toUByte() -> AirPodsGen2(
+                identifier = identifier,
+                scanResult = scanResult,
+                proximityMessage = pm
+            )
+            dm == 0x0e20.toUShort() || dmDirty == 14.toUByte() -> AirPodsPro(
+                identifier = identifier,
+                scanResult = scanResult,
+                proximityMessage = pm
+            )
 //            dmDirty == 10.toUByte() -> {
 //                TODO("Airpods Max")
 //            }
@@ -100,8 +177,12 @@ class AirPodsFactory @Inject constructor(
 //            }
             else -> {
                 log(TAG, WARN) { "Unknown proximity message type" }
-                Bugs.report(IllegalArgumentException("Unknown ProximityMessage: $proximityMessage"))
-                UnknownAppleDevice(scanResult, proximityMessage)
+                Bugs.report(IllegalArgumentException("Unknown ProximityMessage: $pm"))
+                UnknownAppleDevice(
+                    identifier = identifier,
+                    scanResult = scanResult,
+                    proximityMessage = pm
+                )
             }
         }
     }