335 lines
12 KiB
Swift
335 lines
12 KiB
Swift
import Foundation
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import CoreBluetooth
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final class DeviceConnection: NSObject, CBCentralManagerDelegate, ObservableObject {
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static let serviceUUID = CBUUID(string: "22071991-cccc-cccc-cccc-000000000001")
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static let characteristicUUID = CBUUID(string: "22071991-cccc-cccc-cccc-000000000002")
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private var manager: CBCentralManager! = nil
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private(set) var lastRSSI: Int = 0 // TODO: Provide function to update
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@Published
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var state: DeviceState = .disconnected
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var isConnected: Bool {
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// Automatically updates with device state
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if case .configured = state {
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return true
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}
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return false
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}
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override init() {
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super.init()
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self.manager = CBCentralManager(delegate: self, queue: nil)
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}
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/**
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Allow the client to scan for devices and connect to the first device found with the correct characteristic
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*/
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@discardableResult
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func initiateDeviceConnection() -> Bool {
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switch state {
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case .bluetoothDisabled:
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log.info("Can't connect, bluetooth disabled")
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return false
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case .disconnected:
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break
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default:
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return true
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}
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guard !manager.isScanning else {
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state = .scanning
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return true
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}
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shouldConnectIfPossible = true
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state = .scanning
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manager.scanForPeripherals(withServices: [DeviceManager.serviceUUID])
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return true
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}
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@discardableResult
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func updateRSSIForConnectedDevice() -> Bool {
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guard let device = state.device else {
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return false
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}
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device.readRSSI()
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return true
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}
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/**
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Indicate that a connection should be attempted when found.
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This does not necessarily indicate that the phone is scanning for devices.
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*/
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@Published
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var shouldConnectIfPossible = true {
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didSet {
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guard oldValue != shouldConnectIfPossible else {
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return
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}
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updateConnectionOnChange()
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}
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}
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private func updateConnectionOnChange() {
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if shouldConnectIfPossible {
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ensureConnection()
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} else {
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disconnectIfNeeded()
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}
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}
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private func ensureConnection() {
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switch state {
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case .disconnected:
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initiateDeviceConnection()
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default:
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return
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}
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}
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private func disconnectIfNeeded() {
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switch state {
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case .bluetoothDisabled, .disconnected:
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return
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default:
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disconnect()
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}
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}
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func disconnect() {
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shouldConnectIfPossible = false
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switch state {
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case .bluetoothDisabled, .disconnected:
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return
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case .scanning:
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manager.stopScan()
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state = .disconnected
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return
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case .connecting(let device),
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.discoveringCharacteristic(let device),
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.discoveringServices(device: let device),
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.configured(let device, _):
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manager.cancelPeripheralConnection(device)
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manager.stopScan()
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state = .disconnected
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return
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}
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}
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private var requestContinuation: CheckedContinuation<Data?, Never>?
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func getInfo() async -> DeviceInfo? {
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await get(DeviceInfoRequest())
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}
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func getDeviceData(offset: Int, count: Int) async -> Data? {
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await get(DeviceDataRequest(offset: offset, count: count))
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}
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func deleteDeviceData(byteCount: Int) async -> Bool {
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await get(DeviceDataResetRequest(byteCount: byteCount)) != nil
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}
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private func get<Request>(_ request: Request) async -> Request.Response? where Request: DeviceRequest {
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guard requestContinuation == nil else {
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// Prevent parallel requests
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return nil
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}
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guard case .configured(let device, let characteristic) = state else {
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return nil
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}
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let requestData = Data([request.type.rawValue]) + request.payload
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let responseData: Data? = await withCheckedContinuation { continuation in
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requestContinuation = continuation
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device.writeValue(requestData, for: characteristic, type: .withResponse)
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device.readValue(for: characteristic)
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DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(5)) { [weak self] in
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guard let requestContinuation = self?.requestContinuation else { return }
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log.info("Timed out for request \(request.type)")
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requestContinuation.resume(returning: nil)
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self?.requestContinuation = nil
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}
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}
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guard let responseData else {
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return nil
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}
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guard let responseCode = responseData.first else {
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log.error("Request \(request.type) got response of zero bytes")
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return nil
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}
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guard let responseType = BluetoothResponseType(rawValue: responseCode) else {
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log.error("Request \(request.type) got unknown response code \(responseCode)")
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return nil
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}
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switch responseType {
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case .success, .responseTooLarge, .invalidNumberOfBytesToDelete:
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break
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case .invalidCommand:
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log.error("Request \(request.type) failed: Invalid command")
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return nil
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case .unknownCommand:
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log.error("Request \(request.type) failed: Unknown command")
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return nil
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case .responseInProgress:
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log.info("Request \(request.type) failed: Device is busy")
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return nil
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}
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return request.makeResponse(from: responseData.dropFirst(), responseType: responseType)
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}
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func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
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guard shouldConnectIfPossible else {
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return
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}
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peripheral.delegate = self
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manager.connect(peripheral)
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manager.stopScan()
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state = .connecting(device: peripheral)
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}
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func centralManagerDidUpdateState(_ central: CBCentralManager) {
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switch central.state {
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case .poweredOff:
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state = .bluetoothDisabled
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case .poweredOn:
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state = .disconnected
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initiateDeviceConnection()
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case .unsupported:
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state = .bluetoothDisabled
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log.info("Bluetooth is not supported")
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case .unknown:
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state = .bluetoothDisabled
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log.info("Bluetooth state is unknown")
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case .resetting:
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state = .bluetoothDisabled
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log.info("Bluetooth is resetting")
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case .unauthorized:
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state = .bluetoothDisabled
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log.info("Bluetooth is not authorized")
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@unknown default:
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state = .bluetoothDisabled
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log.warning("Unknown state \(central.state)")
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}
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}
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func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {
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log.info("Connected to " + peripheral.name!)
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peripheral.discoverServices([DeviceManager.serviceUUID])
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state = .discoveringServices(device: peripheral)
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}
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func centralManager(_ central: CBCentralManager, didDisconnectPeripheral peripheral: CBPeripheral, error: Error?) {
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log.info("Disconnected from " + peripheral.name!)
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state = .disconnected
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// Attempt to reconnect
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if shouldConnectIfPossible {
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initiateDeviceConnection()
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}
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}
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func centralManager(_ central: CBCentralManager, didFailToConnect peripheral: CBPeripheral, error: Error?) {
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log.warning("Failed to connect device '\(peripheral.name ?? "NO_NAME")'")
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if let error = error {
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log.warning(error.localizedDescription)
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}
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state = manager.isScanning ? .scanning : .disconnected
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// Attempt to reconnect
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if shouldConnectIfPossible {
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initiateDeviceConnection()
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}
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}
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}
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extension DeviceConnection: CBPeripheralDelegate {
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func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?) {
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guard let services = peripheral.services, !services.isEmpty else {
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log.error("No services found for device '\(peripheral.name ?? "NO_NAME")'")
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manager.cancelPeripheralConnection(peripheral)
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return
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}
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guard let service = services.first(where: { $0.uuid.uuidString == DeviceManager.serviceUUID.uuidString }) else {
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log.error("Required service not found for '\(peripheral.name ?? "NO_NAME")': \(services.map { $0.uuid.uuidString})")
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manager.cancelPeripheralConnection(peripheral)
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return
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}
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peripheral.discoverCharacteristics([DeviceManager.characteristicUUID], for: service)
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state = .discoveringCharacteristic(device: peripheral)
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}
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func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {
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if let error = error {
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log.error("Failed to discover characteristics: \(error)")
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manager.cancelPeripheralConnection(peripheral)
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return
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}
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guard let characteristics = service.characteristics, !characteristics.isEmpty else {
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log.error("No characteristics found for device")
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manager.cancelPeripheralConnection(peripheral)
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return
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}
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for characteristic in characteristics {
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guard characteristic.uuid == DeviceManager.characteristicUUID else {
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log.warning("Unused characteristic \(characteristic.uuid.uuidString)")
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continue
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}
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state = .configured(device: peripheral, characteristic: characteristic)
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peripheral.setNotifyValue(true, for: characteristic)
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}
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}
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func peripheral(_ peripheral: CBPeripheral, didWriteValueFor characteristic: CBCharacteristic, error: Error?) {
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if let error = error {
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log.error("Peripheral failed to write value for \(characteristic.uuid.uuidString): \(error)")
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}
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}
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func peripheral(_ peripheral: CBPeripheral, didReadRSSI RSSI: NSNumber, error: Error?) {
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if let error = error {
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log.warning("Failed to get RSSI: \(error)")
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return
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}
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lastRSSI = RSSI.intValue
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log.info("RSSI: \(lastRSSI)")
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}
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func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?) {
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if let error = error {
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log.error("Failed to read value update: \(error)")
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continueRequest(with: nil)
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return
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}
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guard case .configured(device: _, characteristic: let storedCharacteristic) = state else {
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log.warning("Received data while not properly configured")
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continueRequest(with: nil)
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return
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}
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guard characteristic.uuid == storedCharacteristic.uuid else {
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log.warning("Read unknown characteristic \(characteristic.uuid.uuidString)")
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continueRequest(with: nil)
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return
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}
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guard let data = characteristic.value else {
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log.warning("No data")
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continueRequest(with: nil)
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return
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}
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continueRequest(with: data)
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}
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private func continueRequest(with response: Data?) {
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guard let requestContinuation else {
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log.error("No continuation to handle request data (\(response?.count ?? 0) bytes)")
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return
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}
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requestContinuation.resume(returning: response)
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self.requestContinuation = nil
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}
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}
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