BluetoothLeScanner — was es ist, Methoden und BLE-Scannen in Android

// BluetoothLeScanner erhalten
class BLEScannerManager(context: Context) {

    private val bluetoothManager: BluetoothManager =
        context.getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager
    private val adapter: BluetoothAdapter? = bluetoothManager.adapter
    private var scanner: BluetoothLeScanner? = null

    fun initScanner(): Boolean {
        // BLE-Verfügbarkeit prüfen
        if (!context.packageManager.hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
            return false
        }

        // Bluetooth aktiviert prüfen
        if (adapter?.isEnabled != true) {
            return false
        }

        // Scanner erhalten
        scanner = adapter?.bluetoothLeScanner
        return scanner != null
    }

    // Scanner-Verfügbarkeit prüfen
    val isAvailable: Boolean
        get() = scanner != null

    // Basis-Scan ohne Filter starten
    fun startBasicScan() {
        scanner?.startScan(object : ScanCallback() {
            override fun onScanResult(callbackType: Int, result: ScanResult) {
                handleResult(result)
            }
        })
    }

    private fun handleResult(result: ScanResult) {
        val device = result.device
        print("Device: ${device.name ?: "Unnamed"}, RSSI: ${result.rssi}, address: ${device.address}")
    }
}

// ScanSettings-Konfiguration für verschiedene Szenarien
class ScanSettingsProvider {

    // 1. Schneller Scan (aktive Suche)
    fun lowLatencyScan(): ScanSettings {
        return ScanSettings.Builder()
            .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
            .setCallbackType(ScanSettings.CALLBACK_TYPE_ALL_MATCHES)
            .setMatchMode(ScanSettings.MATCH_MODE_AGGRESSIVE)
            .setReportDelay(0)
            .setPhy(ScanSettings.PHY_LE_ALL_SUPPORTED)
            .build()
    }

    // 2. Energieeffizienter Scan (Hintergrundüberwachung)
    fun lowPowerScan(): ScanSettings {
        return ScanSettings.Builder()
            .setScanMode(ScanSettings.SCAN_MODE_LOW_POWER)
            .setCallbackType(ScanSettings.CALLBACK_TYPE_FIRST_MATCH)
            .setMatchMode(ScanSettings.MATCH_MODE_STICKY)
            .setReportDelay(2000)  // Stapel alle 2 Sekunden
            .build()
    }

    // 3. BLE Long Range Scan (Coded PHY)
    fun longRangeScan(): ScanSettings {
        return ScanSettings.Builder()
            .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
            .setPhy(ScanSettings.PHY_LE_CODED)
            .setCallbackType(ScanSettings.CALLBACK_TYPE_ALL_MATCHES)
            .build()
    }

    // 4. Nur auf 2M PHY scannen (BLE 5.0+)
    fun highSpeedScan(): ScanSettings {
        return ScanSettings.Builder()
            .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
            .setPhy(ScanSettings.PHY_LE_2M)
            .build()
    }
}

// ScanFilter-Erstellung für verschiedene Szenarien
class ScanFilterFactory {

    // 1. Nach Dienst-UUID filtern (Herzfrequenzmonitor)
    fun byHeartRateService(): ScanFilter {
        return ScanFilter.Builder()
            .setServiceUuid(
                ParcelUuid.fromString("0000180D-0000-1000-8000-00805F9B34FB")
            )
            .build()
    }

    // 2. Nach Gerätenamen filtern ( "iBeacon*")
    fun byDeviceName(): ScanFilter {
        return ScanFilter.Builder()
            .setDeviceName("Sensor")
            .build()
    }

    // 3.   MAC- ( Geräte)
    fun byMacAddress(mac: String): ScanFilter {
        return ScanFilter.Builder()
            .setDeviceAddress(mac)
            .build()
    }

    // 4. Kombinierter Filter (UUID + )
    fun combinedFilter(): List<ScanFilter> {
        return listOf(
            ScanFilter.Builder()
                .setServiceUuid(
                    ParcelUuid.fromString("0000A001-0000-1000-8000-00805F9B34FB")
                )
                .setDeviceName("MyDevice")
                .build()
        )
    }

    // 5.   Herstellerdaten
    fun byManufacturer(companyId: Int, data: ByteArray, mask: ByteArray): ScanFilter {
        return ScanFilter.Builder()
            .setManufacturerData(companyId, data, mask)
            .build()
    }
}

// Vollständige Scan-Ergebnisse und Fehlerbehandlung
class ScanResultHandler {

    private val results = mutableListOf<ScanResult>()

    val scanCallback = object : ScanCallback() {

        // 1. Einzelergebnis
        override fun onScanResult(callbackType: Int, result: ScanResult) {
            // callbackType: 1 = ALL_MATCHES, 2 = FIRST_MATCH, 4 = MATCH_LOST
            if (callbackType == ScanSettings.CALLBACK_TYPE_MATCH_LOST) {
                onDeviceLost(result)
                return
            }

            // Zur Liste hinzufügen (nach Adresse deduplizieren)
            val existingIndex = results.indexOfFirst {
                it.device.address == result.device.address
            }
            if (existingIndex >= 0) {
                results[existingIndex] = result  // RSSI aktualisieren
            } else {
                results.add(result)
            }

            // Daten aus Werbepaket extrahieren
            val record = result.scanRecord
            val serviceData = record?.serviceData
            val manufacturerData = record?.manufacturerSpecificData

            print("Found: ${result.device.name ?: "N/A"}, RSSI: ${result.rssi}")
        }

        // 2. Stapelergebnisse (reportDelay > 0)
        override fun onBatchScanResults(results: MutableList<ScanResult>?) {
            results?.let { batch ->
                print("Batch: ${batch.size} devices")
            }
        }

        // 3. Scan-Fehler
        override fun onScanFailed(errorCode: Int) {
            val error = when (errorCode) {
                ScanCallback.SCAN_FAILED_ALREADY_STARTED -> "Already scanning"
                ScanCallback.SCAN_FAILED_APPLICATION_REGISTRATION_FAILED -> "Registration failed"
                ScanCallback.SCAN_FAILED_INTERNAL_ERROR -> "Internal error"
                ScanCallback.SCAN_FAILED_FEATURE_UNSUPPORTED -> "BLE not supported"
                else -> "Unknown error: $errorCode"
            }
            print("Error: $error")
        }
    }

    private fun onDeviceLost(result: ScanResult) {
        results.removeAll { it.device.address == result.device.address }
        print("Device lost: ${result.device.address}")
    }
}

// Hintergrund-BLE-Scannen über PendingIntent
class BackgroundBLEScanner(private val context: Context) {

    private val scanner: BluetoothLeScanner? by lazy {
        val adapter = BluetoothAdapter.getDefaultAdapter()
        adapter?.bluetoothLeScanner
    }

    fun startBackgroundScan() {
        // PendingIntent für BroadcastReceiver erstellen
        val intent = Intent(context, BLEBroadcastReceiver::class.java)
        val pendingIntent = PendingIntent.getBroadcast(
            context,
            0,
            intent,
            PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE
        )

        // Hintergrund-Scan-Einstellungen
        val settings = ScanSettings.Builder()
            .setScanMode(ScanSettings.SCAN_MODE_LOW_POWER)
            .setCallbackType(ScanSettings.CALLBACK_TYPE_FIRST_MATCH)
            .setMatchMode(ScanSettings.MATCH_MODE_STICKY)
            .build()

        // Hintergrund-Scan starten
        scanner?.startScan(
            null,  // Filter
            settings,
            pendingIntent
        )
    }

    fun stopBackgroundScan() {
        val intent = Intent(context, BLEBroadcastReceiver::class.java)
        val pendingIntent = PendingIntent.getBroadcast(
            context, 0, intent,
            PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE
        )
        scanner?.stopScan(pendingIntent)
    }
}

// BroadcastReceiver   BLE-
class BLEBroadcastReceiver : BroadcastReceiver() {

    override fun onReceive(context: Context, intent: Intent) {
        // Scan-Ergebnisse abrufen
        val results = BluetoothLeScanner.getPendingIntentScanResults(intent)
        results?.let { scanResults ->
            for (result in scanResults) {
                // Benachrichtigung an Benutzer senden
                showNotification(context, result.device.name ?: " ")
            }
        }
    }

    private fun showNotification(context: Context, name: String) {
        val notification = Notification.Builder(context, "ble_channel")
            .setSmallIcon(android.R.drawable.ic_dialog_info)
            .setContentTitle("BLE devices")
            .setContentText("Found: $name")
            .setAutoCancel(true)
            .build()
        val manager = context.getSystemService(Context.NOTIFICATION_SERVICE)
                as NotificationManager
        manager.notify(System.currentTimeMillis().toInt(), notification)
    }
}

// Vollständiger BLE-Scanner mit Coroutinen in Kotlin
class DeviceScanner(private val context: Context) {

    private val adapter: BluetoothAdapter? by lazy {
        val manager = context.getSystemService(Context.BLUETOOTH_SERVICE)
                as BluetoothManager
        manager.adapter
    }

    private val scanner: BluetoothLeScanner? by lazy {
        adapter?.bluetoothLeScanner
    }

    fun startScan(duration: Long = 10000): Flow<ScanResult> = callbackFlow {
        // Bluetooth-Status prüfen
        if (adapter?.isEnabled != true) {
            close(IllegalStateException("Bluetooth disabled"))
            return@callbackFlow
        }

        // Scan-Konfiguration
        val settings = ScanSettings.Builder()
            .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
            .build()

        val filters = listOf(
            ScanFilter.Builder()
                .setServiceUuid(ParcelUuid.fromString("0000180D-0000-1000-8000-00805F9B34FB"))
                .build()
        )

        val callback = object : ScanCallback() {
            override fun onScanResult(callbackType: Int, result: ScanResult) {
                trySend(result)
            }

            override fun onScanFailed(errorCode: Int) {
                close(BLEException("Scan failed: $errorCode"))
            }
        }

        // Scannen starten
        scanner?.startScan(filters, settings, callback)

        // Automatischer Stopp nach Zeit
        delay(duration)
        scanner?.stopScan(callback)
        close()
    }.flowOn(Dispatchers.IO)

    fun stop() {
        scanner?.stopScan(object : ScanCallback() {})
    }
}

class BLEException(message: String) : Exception(message)